Air conditioning and hot water supply system

Abstract

An air-conditioning hot-water-supply system (1) includes: a refrigeration circuit (21) that includes a heating-medium heat exchanger (11) configured to exchange heat between a refrigerant and a heating medium and can perform heating and cooling of the heating medium by the refrigerant in the heating-medium heat exchanger (11); a common path (41a) connected to a utilization side of the heating-medium heat exchanger (11), allowing a cooled heating medium to flow through the common path (41a) during a cooling operation, and allowing a heated heating medium to flow through the common path (41a) during a hot water supply operation; a heater (13) heating the heating medium; and a controller (10) controlling the refrigeration circuit (21) and the heater (13). The controller (10) turns on the heater (13) for a predetermined period of time at a time of switching from the cooling operation to the hot water supply operation.

Description

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to an air-conditioning hot-water-supply system.BACKGROUND

[0002] A known heat source system can perform hot water supply, cooling and heating, and thermal storage and cooling using the same heat source. For example, such a heat source system uses a heat pump of a single heat source for performing: cooling and heating, thermal storage and cooling, hot water storage, hot water supply, and bath reheating. Furthermore, this heat source system controls these operations by a single control system.PRIOR ART DocumentPATENT DOCUMENT

[0003] [Patent Document 1] JP H07-253228 ASUMMARYPROBLEM TO BE SOLVED BY INVENTION

[0004] In an air-conditioning hot-water-supply system that includes a heat pump-type refrigeration cycle and performs air conditioning and hot water supply by using a heating medium such as water, the hot water stored in a hot water tank is heated by the heating medium that is heated by the heat pump. During a cooling operation or during a heating operation, the heating medium cooled or heated by the heat pump is supplied to air-conditioning equipment such as a fan coil unit provided indoors.

[0005] In such an air-conditioning hot-water-supply system, the cooling operation and the hot water supply operation may be set simultaneously during the summer. In this case, the heating medium is single, and accordingly, the cooling operation and the hot water supply operation cannot be performed at the same time. Hence, both indoor cooling and heating of the hot water stored in the hot water tank can be achieved by alternately performing the cooling operation and the heating operation by means of: (i) cooling and heating of the heating medium using the heat pump at predetermined time intervals; and (ii) switching of valves that change the flow path of the heating medium in conjunction therewith.

[0006] However, when it switches from the cooling operation to the hot water supply operation, the cooled heating medium (circulating water) remains in the path common to both the cooling path and the hot water supply path, through which the heating medium flows. In addition, during the cooling operation, pipes made of metal such as copper and located in the common path are also cooled and remain at a low temperature. Thus, when it switches from the cooling operation to the hot water supply operation, the cooled heating medium flows into the hot water tank, thereby lowering the temperature of the stored hot water in the hot water tank. In the following, the temperature of the stored hot water is abbreviated as "the stored hot water temperature".

[0007] Moreover, the cooling operation and the hot water supply operation are alternately switched at predetermined time intervals, and accordingly, the time available for heating the hot water tank during the hot water supply operation is limited. Consequently, each time it switches from the cooling operation to the hot water supply operation, the stored hot water temperature in the hot tank decreases and the time required for the stored hot water temperature to reach the hot-water-supply set temperature becomes longer.

[0008] The present invention aims to provide an air-conditioning hot-water-supply system that can suppress a decrease in the stored hot water temperature in the hot water tank so as to shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature at the time of switching from the cooling operation to the hot water supply operation.MEANS FOR SOLVING PROBLEM

[0009] To solve the above problems, an air-conditioning hot-water-supply system according to one embodiment of the present invention includes: a refrigeration circuit that includes a heating-medium heat exchanger configured to exchange heat between a refrigerant and a heating medium and can perform heating and cooling of the heating medium by the refrigerant in the heating-medium heat exchanger; a common path that is connected to a utilization side of the heating-medium heat exchanger, allows a cooled heating medium to flow through the common path during a cooling operation using the heating medium cooled by the refrigeration circuit, and allows a heated heating medium to flow through the common path during a hot water supply operation using the heating medium heated by the refrigeration circuit; a heater that heats the heating medium; and a controller that controls the refrigeration circuit and the heater, wherein the controller turns on the heater for a predetermined period of time at a time of switching from the cooling operation to the hot water supply operation.

[0010] Preferably, the air-conditioning hot-water-supply system according to the embodiment of the present invention further includes: a first heating-medium circulation circuit to which the common path is connected, and through which the cooled heating medium flows during the cooling operation; a second heating-medium circulation circuit to which the common path is connected, and through which the heated heating medium flows during the hot water supply operation; a flow-path switching device that is connected to the common path, the first heating-medium circulation circuit, and the second heating-medium circulation circuit and switches a flow of the heating medium from the common path to either the first heating-medium circulation circuit or the second heating-medium circulation circuit; and a pump that circulates the heating medium, wherein: the heater is provided in the common path or in the second heating-medium circulation circuit; and the controller is configured to further control the flow-path switching device and the pump.

[0011] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes: a hot water tank that is connected to the second heating-medium circulation circuit and exchanges heat between the heated heating medium and stored water; and a hot-water-tank temperature sensor that is provided in the hot water tank and detects the stored hot water temperature in the hot water tank.

[0012] Preferably, the air-conditioning hot-water-supply system according to the embodiment of the present invention further includes an inlet temperature sensor that is provided at an inlet of the heating medium of the heating-medium heat exchanger, wherein the predetermined period of time is set to be a period of time until a temperature of the heating medium detected by the inlet temperature sensor reaches or exceeds the stored hot water temperature detected by the hot-water-tank temperature sensor.

[0013] The heater and the pump of the air-conditioning hot-water-supply system according to the embodiment of the present invention are preferably provided in the common path.

[0014] The refrigeration circuit of the air-conditioning hot-water-supply system according to the embodiment of the present invention preferably includes a compressor configured to compress the refrigerant. The controller is preferably configured to temporarily turn off the pump at a time of switching from the cooling operation to the hot water supply operation, and turn on the heater after turning on the pump again and before turning on the compressor.

[0015] The refrigeration circuit of the air-conditioning hot-water-supply system according to the embodiment of the present invention preferably includes: an air heat exchanger configured to exchange heat between the refrigerant and ambient air; and a temperature sensor configured to detect an ambient temperature at a location where the air heat exchanger is installed. The controller is preferably configured to turn on the heater when the ambient temperature detected by the temperature sensor is equal to or below a predetermined temperature during the hot water supply operation.

[0016] The controller of the air-conditioning hot-water-supply system according to the embodiment of the present invention is preferably configured to perform switching between the cooling operation and the hot water supply operation alternately at predetermined time intervals, when simultaneous requests for the cooling operation and the hot water supply operation occur.

[0017] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, and the heater.

[0018] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, the heater, and the hot water tank.EFFECTS OF INVENTION

[0019] The present invention can provide an air-conditioning hot-water-supply system that can suppress a decrease in the stored hot water temperature in the hot water tank so as to shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature at the time of switching from the cooling operation to the hot water supply operation.BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a system configuration diagram of an air-conditioning hot-water-supply system according to one embodiment of the present invention. Fig. 2 is a conceptual diagram illustrating time-series changes in a stored hot water temperature, a water-heat-exchanger inlet temperature, and an operation of a heater during a cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 3 is a combination of: (i) a timing chart illustrating an operation of each component during the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention; and (ii) a diagram illustrating the corresponding time variations of the water-heat-exchanger inlet temperature and the stored hot water temperature. Fig. 4 is a diagram illustrating time variations of the stored hot water temperature and the water-heat-exchanger inlet temperature during the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 5 is a timing chart illustrating an operation of each component during a heating / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 6 is a diagram illustrating a control flow of each operation mode in the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 7 is a diagram illustrating a control flow of the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 8 is a diagram illustrating a control flow of the heating / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. DETAILED DESCRIPTION

[0021] An air-conditioning hot-water-supply system according to the present embodiment will be described by referring to Figs. 1 to 8.

[0022] As shown in Fig. 1, the air-conditioning hot-water-supply system 1 includes: an outdoor unit 2 serving as a heat pump unit configured to exchange heat between the surrounding (outdoor) air and a refrigerant; a heat exchange unit 3 (i.e., hydro unit) accommodating a heating-medium heat exchanger 11 that exchanges heat between the refrigerant and a utilization-side heating medium; a plurality of external apparatuses 5 connected to the heat exchange unit 3; a remote controller 9 serving as an input device for receiving user operations; and a controller 10 configured to control respective components of the outdoor unit 2 and the heat exchange unit 3 on the basis of operations inputted to the remote controller 9. The external apparatuses 5 include at least one of a radiator 6 of a floor heating / cooling system and a fan coil unit 7 serving as an indoor unit of an air-conditioning system. It is sufficient that the number of the external apparatuses 5 is one or more.

[0023] Although water is used as the utilization-side heating medium in the present embodiment, the utilization-side heating medium is not limited to water and may be another fluid such as an antifreeze solution. Hereinafter, the utilization-side heating medium is simply referred to as the heating medium, circulating water, or water, and the heating-medium heat exchanger 11 is referred to as the water heat exchanger 11. As to the refrigerant, any suitable refrigerant, such as R410A, R32, and CO 2 , may be used.

[0024] The air-conditioning hot-water-supply system 1 includes a refrigeration circuit 21 that circulates the refrigerant through the outdoor unit 2 and the heat exchange unit 3. The refrigeration circuit 21 includes: a compressor 23 that compresses and discharges the refrigerant; a four-way valve 29 that switches the direction of the refrigerant flow; an air heat exchanger 25 that functions as an evaporator and a condenser for exchanging heat between the refrigerant and the surrounding air; an expansion valve 27; the water heat exchanger 11 that functions as a condenser and an evaporator for exchanging heat between the refrigerant and the circulating water; and refrigerant piping 14 that connects these components to circulate the refrigerant. The water heat exchanger 11 is a plate-type heat exchanger or a heat exchanger such as a double-pipe type. The refrigeration circuit 21 may also be referred to as a heat pump.

[0025] Of the components of the refrigeration circuit 21, the compressor 23, the four-way valve 29, the air heat exchanger 25, the expansion valve 27, and a part of the refrigerant piping 14 are accommodated in the outdoor unit 2. The heat exchange unit 3 accommodates: a part of the refrigerant piping 14; a heater 13; a hot water tank 12; piping that serves as a flow path for the circulating water; a first pump 45 and a second pump 91, both of which circulate the circulating water as described below; a flow-path switching device 89 that switches the flow path of the circulating water; various sensors; and the controller 10. Water to be stored in the hot water tank 12 having a capacity of about 100 to 300 liters is generally tap water to be supplied from outside through a water supply pipe and is heated by the circulating water. Hot water heated in the hot water tank 12, i.e., stored hot water, is supplied to hot-water supply destinations such as a washroom, a kitchen, and a bathroom. The controller 10 may be accommodated not only in the heat exchange unit 3 but also in the outdoor unit 2 or in the remote controller 9. Additionally or alternatively, a plurality of controllers 10 may be distributed among the heat exchange unit 3, the outdoor unit 2, and / or the remote controller 9 so that the respective controllers 10 operate in coordination with each other.

[0026] In general, the outdoor unit 2 is installed outdoors, and the heat exchange unit 3 is installed indoors. The outdoor unit 2 and the heat exchange unit 3 are connected to each other via connecting pipes 15 and 16 of the refrigerant piping 14 and communication lines (not shown). That is, only the refrigerant flows between the outdoor unit 2 and the heat exchange unit 3, and thus, the air-conditioning hot-water-supply system 1 does not require any outdoor piping through which the circulating water flows. Accordingly, the air-conditioning hot-water-supply system 1 can avoid freezing of the circulating water in the outdoor piping under low ambient temperature conditions.

[0027] During the cooling operation, the air-conditioning hot-water-supply system 1 cools the circulating water with the refrigeration circuit 21, and circulates the circulating water having a temperature of 7°C to 25°C to the external apparatuses 5, for example.

[0028] During the heating operation and during a hot water supply operation, the air-conditioning hot-water-supply system 1 heats the circulating water with the heat pump to obtain the circulating water at a first temperature, for example, 20°C to 65°C.

[0029] During the heating operation, the air-conditioning hot-water-supply system 1 circulates the circulating water at the first temperature to the external apparatuses 5 without causing the circulating water to pass through the hot water tank 12. During the hot water supply operation, the air-conditioning hot-water-supply system 1 circulates the circulating water at the first temperature to the hot water tank 12 without causing the circulating water to pass through the external apparatuses 5.

[0030] During the hot water supply operation, the air-conditioning hot-water-supply system 1 can combine heating of the circulating water with the heat pump and heating of the circulating water with the heater 13, which is provided downstream of the water heat exchanger 11 in the heat exchange unit 3, and thereby can circulate the circulating water at a second temperature higher than the first temperature, for example, about 65°C, to the hot water tank 12. As a result, the air-conditioning hot-water-supply system 1 can store hot water at about 65°C in the hot water tank 12. When the ambient temperature around the outdoor unit 2, i.e., the outside air temperature, is extremely low, for example, below -20°C, heating of the circulating water by the heat pump becomes insufficient, and thus, the heater 13 is turned on to promote heating of the circulating water.

[0031] During the hot water supply operation, the air-conditioning hot-water-supply system 1 performs so-called boiling-up, i.e., heating of the water stored in the hot water tank 12, by using the circulating water circulating through the heat exchange unit 3.

[0032] The air-conditioning hot-water-supply system 1 having the above-described configuration includes, as its basic functions, the following: (1) A function of circulating the refrigerant between the outdoor unit 2 and the heat exchange unit 3 and thereby exchanging heat between the refrigerant and the circulating water in the water heat exchanger 11 of the heat exchange unit 3. (2) A function of circulating either the cooled circulating water or the heated circulating water between the heat exchange unit 3 and the plurality of external apparatuses 5 and thereby air-conditioning the rooms in which the external apparatuses 5 are installed. (3) A function of circulating the heated circulating water within the hot water tank 12 to heat the water stored therein to heat and produce hot water and thereby supplying the hot water to hot-water destinations as needed.

[0033] The outdoor unit 2 is provided with an outside-air temperature sensor 26. The outside-air temperature sensor 26 detects an outside air temperature To, which is defined as the upstream air temperature before passing through the air heat exchanger 25 and is the ambient temperature of the air heat exchanger 25, and outputs the outside air temperature To to the controller 10.

[0034] The compressor 23 compresses the refrigerant and discharges the refrigerant at an elevated pressure. It is preferred that the compressor 23 can vary its operating frequency by known inverter control through an inverter device (not shown). Increasing the rotational speed of the compressor 23 increases the amount of heat to be transferred to the high-temperature side, whereas decreasing the rotational speed reduces the amount of heat to be transferred to the high-temperature side. In this case, the controller 10 detects an air-conditioning load or a hot-water-supply load, and adjusts the operating frequency of the inverter device depending on the detection result, thereby enabling it to exhibit an appropriate refrigeration capacity corresponding to the load state.

[0035] The expansion valve 27 is, for example, an electronic expansion valve, such as a pulse motor valve (PMV), with an electrically adjustable degree of opening.

[0036] The four-way valve 29 switches the flow direction of the refrigerant that circulates through the compressor 23, the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11. When the circulating water is heated in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 to flow through the water heat exchanger 11, the expansion valve 27, and the air heat exchanger 25 in this order. The solid arrows in Fig. 1 indicate this flow of the refrigerant. In this case, the water heat exchanger 11 functions as a condenser.

[0037] The refrigerant having passed through the water heat exchanger 11 returns to the outdoor unit 2 via the connecting pipe 16, passes through the expansion valve 27 to be depressurized, and becomes a low-pressure gas-liquid two-phase refrigerant. Thereafter, the low-pressure gas-liquid two-phase refrigerant is sent to the air heat exchanger 25. The air heat exchanger 25 is ventilated with the outside air by a blower (not shown). The low-pressure gas-liquid two-phase refrigerant is heated by the outside air passing through the air heat exchanger 25 and becomes a gas-phase refrigerant. In this case, the air heat exchanger 25 functions as an evaporator. After passing through the air heat exchanger 25 and becoming a gas-phase refrigerant, the refrigerant returns to the compressor 23. The evaporator is also referred to as a heat absorber, and the condenser is also referred to as a radiator.

[0038] When the circulating water is cooled in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 to flow through the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11 in this order. The dashed arrows in Fig. 1 indicate this flow of the refrigerant. In this case, the high-temperature and high-pressure refrigerant discharged from the compressor 23 is sent to the air heat exchanger 25 via the four-way valve 29. The high-temperature and high-pressure refrigerant is cooled by the outside air passing through the air heat exchanger 25 and becomes a high-pressure liquid-phase refrigerant. In this case, the air heat exchanger 25 functions as a condenser.

[0039] The refrigerant having passed through the air heat exchanger 25 passes through the expansion valve 27 to be depressurized, thereby becomes a low-pressure gas-liquid two-phase refrigerant, is sent to the heat exchange unit 3 via the connecting pipe 16, and then enters the water heat exchanger 11. The water heat exchanger 11 cools the circulating water flowing through the water heat exchanger 11 by the refrigerant passing through the water heat exchanger 11. The refrigerant that has cooled the circulating water in the water heat exchanger 11 is heated and becomes a low-pressure gas-phase refrigerant. In this case, the water heat exchanger 11 functions as an evaporator. After passing through the water heat exchanger 11 and becoming gas-phase, the refrigerant returns to the outdoor unit 2 via the connecting pipe 15 and is then drawn into the compressor 23.

[0040] The heat exchange unit 3 includes a part of a heating-medium circulation circuit 41 that is a water circuit configured to: (i) circulate the circulating water subjected to heat exchange in the water heat exchanger 11 between the water heat exchanger 11 and the plurality of external apparatuses 5 during the cooling operation and during the heating operation; and (ii) circulate the circulating water heated in the water heat exchanger 11 between the water heat exchanger 11 and the hot water tank 12 during the hot water supply operation. The flow direction of the circulating water is selectively switched either toward the side of the external apparatuses 5 or toward the side of the hot water tank 12 by the flow-path switching device 89.

[0041] The heating-medium circulation circuit 41 is provided with: an outlet temperature sensor 51 installed at the outlet of the circulating water of the water heat exchanger 11; an inlet temperature sensor 52 installed at the inlet of the circulating water of the water heat exchanger 11; and a flow sensor 53 configured to measure a flow rate of the circulating water. The outputs of the outlet temperature sensor 51, the inlet temperature sensor 52, and the flow sensor 53 are supplied to the controller 10 in the same manner as the outputs of the other sensors. The circulating water circulates in one direction through the heating-medium circulation circuit 41 by the operation of the first pump 45. The heating-medium circulation circuit 41 includes a circulating-water pipe 43. The circulating-water pipe 43 and other pipes through which the circulating water flows are formed of metal pipes, such as a copper pipe and an iron pipe.

[0042] The outlet temperature sensor 51 detects the temperature of the circulating water immediately after heat exchange by the water heat exchanger 11 and outputs the detected temperature to the controller 10. The inlet temperature sensor 52 detects the temperature of the circulating water immediately before heat exchange by the water heat exchanger 11 and outputs the detected temperature to the controller 10. The temperature detected by the inlet temperature sensor 52 corresponds to the temperature of the circulating water returned after heat exchange with the indoor air by the plurality of external apparatuses 5 during the air-conditioning operation for heating or cooling, and corresponds to the temperature of the circulating water returned after heat exchange with feed water in the hot water tank 12 during the hot water supply operation. Hereinafter, the temperature of the circulating water detected by the inlet temperature sensor 52 is referred to as the water-heat-exchanger inlet temperature.

[0043] During the hot water supply operation, the circulating water heated by the water heat exchanger 11 is drawn by the driven first pump 45 and delivered through the circulating-water pipe 43 to the hot water tank 12. The circulating water exchanges heat with the feed water in the hot water tank 12 to heat the feed water. The circulating water, decreased in temperature due to the heat exchange, is returned to the water heat exchanger 11 so as to be heated by the refrigerant circulating in the refrigeration circuit 21, and then circulates again within the heating-medium circulation circuit 41.

[0044] The hot water tank 12 includes: a tank 61 that is made of stainless steel and can store the feed water; a feed water pipe 65 that supplies the feed water such as city water into the tank 61 through an outlet 63 of the feed water pipe 65 provided at the lower portion of the tank 61; a coil 67 that circulates the circulating water within the tank 61 and indirectly heats the feed water in the tank 61; a hot water tank temperature sensor 69 that detects the stored hot water temperature in the tank 61; a hot-water supply pipe 71 that guides the stored water heated in the tank 61 to the outside of the tank 61; and an insulation member 73 that covers the outer surface of the tank 61.

[0045] The tank 61 is a sealed container except for the feed water pipe 65 and the hot-water supply pipe 71. When the stored hot water is delivered to the hot-water supply destination connected to the hot-water supply pipe 71, water is supplied into the tank 61 through the outlet 63 of the feed water pipe 65 to compensate for the discharged amount of the hot water. Thus, the interior of the tank 61 is always maintained full of water. The hot-water supply pipe 71 for supplying the stored hot water in the tank 61 is provided in an upper end plate 75, which constitutes the top of the tank 61. In general, the hot water tank 12 supplies the stored hot water in the tank 61 to the destination connected to the hot-water supply pipe 71 by pushing out the stored hot water in the tank 61 using the water pressure of the tap water in the supply pipe connected to the feed water pipe 65.

[0046] The coil 67 includes: a circulating-water inlet pipe 67a that penetrates the upper end plate 75 in the vertical direction and extends linearly downward within the tank 61; a helical portion 67b that is helically wound following the circulating-water inlet pipe 67a; and a circulating-water return pipe 67c that extends linearly upward within the tank 61 from the end of the helical portion 67b and penetrates the upper end plate 75 in the vertical direction. The space around the coil 67 located in the tank 61 is filled with water. The feed water and / or the stored hot water are heated by heat exchange between: (i) the high-temperature circulating water circulating within the coil 67; and (ii) the feed water and / or the stored hot water in the hot water tank 12.

[0047] The hot-water-tank temperature sensor 69 detects a representative value of the stored hot water temperature in the tank 61. The output of the hot-water-tank temperature sensor 69 is inputted to the controller 10. The hot-water-tank temperature sensor 69 is provided in the interior of a thin tubular temperature-sensor holder 77, which protrudes downward from the upper end plate 75. The temperature-sensor holder 77 extends from a location suitable for detecting the stored hot water temperature in the tank 61, for example, from the upper end plate 75, downward toward the central portion of the tank 61. Specifically, the inner circumferential surface of the temperature-sensor holder 77 is connected to the outer surface of the tank 61, and the outer circumferential surface of the temperature-sensor holder 77 is connected to the inner surface of the tank 61. The hot-water-tank temperature sensor 69 detects the stored hot water temperature transmitted from the outer surface to the inner surface of the temperature-sensor holder 77.

[0048] The insulation member 73 is provided around the tank 61 and suppresses direct heat radiation to the atmosphere, thereby preventing a decrease in the stored hot water temperature in the tank 61. The material of the insulation member 73 is a foamed polystyrene material or a foamed urethane material having higher thermal insulation performance than the foamed polystyrene material. A vacuum insulation material having even higher thermal insulation performance may also be used. The lower portion of the tank 61 is supplied with tap water, which is unheated feed water, from the outlet 63 of the feed water pipe 65 provided at the lower portion, and has no insulation material because the need for heat retention is low.

[0049] Focusing on the circulation path of the circulating water, the heating-medium circulation circuit 41 includes: an external circulating-water pipe 87 that is located farther from the water heat exchanger 11 than the circulating-water pipe 43 and circulates the circulating water through the external apparatuses 5; a branching point Z where the circulating water flowing through the circulating-water pipe 43 branches off toward the external circulating-water pipe 87; and the flow-path switching device 89 that switches the circulation path of the circulating water to either the side of the hot water tank 12 or the side of the external apparatuses 5, in addition to the circulating-water pipe 43.

[0050] The circulating-water pipe 43 includes: a forward pipe 81 that directs the circulating water heated by the water heat exchanger 11 to the coil 67 of the hot water tank 12 or to the external apparatuses 5; and a return pipe 83 that directs the circulating water decreased in temperature after heating the feed water in the tank 61 or the circulating water having undergone heat exchange in the external apparatuses 5 to the water heat exchanger 11.

[0051] In the forward pipe 81, a first pump 45 configured to circulate the circulating water, a heater 13 configured to heat the circulating water passing therethrough, and an expansion tank 49 configured to absorb expansion (i.e., an increase in volume) of the heated circulating water are provided in this order. The expansion tank 49 is independently connected to a pipe branched from the forward pipe 81. The flow sensor 53 is provided in the middle of the return pipe 83.

[0052] The external circulating-water pipe 87 includes: an external forward pipe 95 configured to guide the circulating water toward the external apparatuses 5 in one of two directions branched from the branching point Z located at a terminal end of the forward pipe 81; and an external return pipe 97 configured to return the circulating water used in the external apparatuses 5 to the return pipe 83. The circulating-water inlet pipe 67a configured to introduce the circulating water into the hot water tank 12 is connected to the other branch from the branching point Z.

[0053] The external forward pipe 95 branches into two directions: a first forward pipe 95a that supplies the circulating water to the radiator 6 at an intermediate portion; and a second forward pipe 95b that supplies the circulating water to the indoor unit 7. In the external return pipe 97, a first return pipe 97a for returning the circulating water from the radiator 6 and a second return pipe 97b for returning the circulating water from the indoor unit 7 merge.

[0054] A mixing valve 93 and the second pump 91 are sequentially connected to the second forward pipe 95b. One end of the mixing valve 93 is connected to an intermediate portion of the second return pipe 97b. The opening degree of the mixing valve 93 is adjusted to vary the amount of mixing between a portion of the circulating water used by the indoor unit 7 and the circulating water supplied to the indoor unit 7, thereby controlling the temperature of the circulating water flowing through the indoor unit 7 to satisfy the temperature requirement that has been set for the indoor unit 7. The second pump 91 operates only when the indoor unit 7 requests the cooling operation or the heating operation and the requested operation can be performed, and remains stopped during other operating states, such as during the hot water supply operation. The circulating water used in the external apparatuses 5 is returned to the return pipe 83 of the heating-medium circulation circuit 41 between the hot water tank 12 and the water heat exchanger 11 through the external return pipe 97 of the external circulating-water pipe 87.

[0055] Although the air-conditioning hot-water-supply system 1 can supply the cooled or heated circulating water to two external apparatuses 5 (the radiator 6 and the indoor unit 7) in the present embodiment, the number of the external apparatus 5 may be only one.

[0056] At the branching point Z, the circulating water from the forward pipe 81 flows into the external forward pipe 95 during the cooling operation and during the heating operations, and flows into the other branch, i.e., the circulating-water inlet pipe 67a, during the hot water supply operation.

[0057] Although various forms such as a combination of a plurality of valves can be adopted as the flow-path switching device 89, in the present embodiment, a description will be given of a case of using a three-way valve 89, which allows the simplest piping configuration. The three-way valve 89 includes an outlet configured to be always open and two inlets configured to be switched such that only one of the two inlets is connected to the outlet. The outlet of the three-way valve 89 is connected to the return pipe 83, one of its inlets is connected to the external return pipe 97, and the other inlet is connected to the circulating-water return pipe 67c extending from the interior of the hot water tank 12. Accordingly, the flow path of the circulating water can be directed to either the side of the hot water tank 12 or the side of the external apparatuses 5 by switching the connection direction of the three-way valve 89 between the time of the cooling and heating operations and the time of the hot water supply operation.

[0058] As described above, the heating-medium circulation circuit 41 includes: a circulation path for the circulating water that circulates on the side of the external apparatuses 5; and another circulation path for the circulating water that circulates on the side of the hot water tank 12. These circulation paths share a common portion. The common path 41a serving as this common portion includes the following two segments: (i) the forward pipe 81 that is connected to the outlet pipe on the utilization side of the water heat exchanger 11 and extends from the water heat exchanger 11 to the branching point Z; and (ii) the return pipe 83 that is connected to the inlet pipe on the utilization side of the water heat exchanger 11 and extends from the three-way valve 89 to the water heat exchanger 11.

[0059] The portion of the circulation path for the circulating water circulating on the side of the external apparatuses 5 other than the common path 41a is hereinafter referred to as the first heating-medium circulation circuit 41b. The portion of the circulation path for the circulating water circulating on the side of the hot water tank 12 other than the common path 41a is hereinafter referred to as the second heating-medium circulation circuit 41c.

[0060] Accordingly, the outlet of the three-way valve 89 is connected to the common path 41a, one of the inlets of the three-way valve 89 is connected to the first heating-medium circulation circuit 41b, and the other inlet of the three-way valve 89 is connected to the second heating-medium circulation circuit 41c. The first heating-medium circulation circuit 41b substantially corresponds to the path of the external circulating-water pipe 87. Specifically, the second heating-medium circulation circuit 41c is a path extending from the branching point Z through the circulating-water inlet pipe 67a, the helical portion 67b within the hot water tank 12, and the circulating-water return pipe 67c to the three-way valve 89.

[0061] In accordance with instructions from the controller 10, the air-conditioning hot-water-supply system 1 can selectively switch the circulation path of the circulating water either toward the first heating-medium circulation circuit 41b or toward the second heating-medium circulation circuit 41c at predetermined time intervals in a time-division manner using the three-way valve 89 in such a manner that: (i) the cooling operation of the external apparatuses 5 and the hot water supply operation of the hot water tank 12 are concurrently performed; and / or (ii) the hot water supply operation and the heating operation of the external apparatuses 5 are concurrently performed.

[0062] The common path 41a includes the heater 13, the expansion tank 49, and the first pump 45 provided in the forward pipe 81. The heater 13 may be relocated to the second heating-medium circulation circuit 41c. In this case, however, the heater 13 cannot be used as an auxiliary heat source during the heating operation of the external apparatuses 5.

[0063] At least one remote controller 9 is provided. The remote controller(s) 9 may include a remote controller provided in the outdoor unit 2, another remote controller provided in the heat exchange unit 3, and still another remote controller installed on an indoor wall (not shown), for example.

[0064] The remote controller 9 includes: a setting unit (not shown) that serves as an input interface for setting the set temperature of the circulation water and / or the operation mode of the air-conditioning hot-water-supply system 1; and a display (not shown) that displays the contents of the settings as operation conditions of the outdoor unit 2, the heat exchange unit 3, and the external apparatuses 5 and the operating states of them. The remote controller 9 transmits the following three items to the controller 10 as control signals, which are set by the user via the setting unit: (i) the set temperature of the circulating water to be circulated to the external apparatuses 5; (ii) the set temperature for boiling water in the hot water tank 12 (i.e., the hot-water-supply set temperature); and (iii) the operation mode of the air-conditioning hot-water-supply system 1.

[0065] The controller 10 includes a microprocessor (not shown) and a storage device (not shown) that stores various parameters and computation programs to be executed by the microprocessor. The controller 10 reads the various control programs from an auxiliary storage device into a main storage device, and executes the control programs read into the main storage device in a central processing unit within the microprocessor. The controller 10 executes sequence control on the basis of: (i) instructions from the remote controller 9; and (ii) detection values from various sensors, such as the outlet temperature sensor 51, the inlet temperature sensor 52, and the flow sensor 53. The controller 10 may be configured with a logic circuit to execute the sequence control.

[0066] On the basis of the control signals received from the remote controller 9 via a wired or wireless communication line and outputs from various sensors, the controller 10 executes the operation control of the air-conditioning hot-water-supply system 1 including: (i) control of the four-way valve 29 and the compressor 23 of the refrigeration circuit 21; and (ii) control of the first pump 45, the three-way valve 89, and the heater 13 in the heat exchange unit 3. For example, the controller 10 executes the operation control of the air-conditioning hot-water-supply system 1 such that the temperature detected by the hot-water-tank temperature sensor 69 within the tank 61 becomes the hot-water-supply set temperature of the hot water tank 12.

[0067] The controller 10 switches the path of the circulating water from the common path 41a to either the first heating-medium circulation circuit 41b on the side of the external apparatuses 5 or the second heating-medium circulation circuit 41c on the side of the hot water tank 12 by controlling the switching of the three-way valve 89. Furthermore, the controller 10 alternately switches the circulation path of the circulating water between the side of the external apparatuses 5 and the side of the hot water tank 12, thereby enabling both boiling of the stored hot water in the hot water tank 12 and supply of the circulating water to the external apparatuses 5. The remote controller 9 allows a user to set an operation mode of switching these operating states via the operation unit. [Table 1]HOT WATER TANKTEMPERATURE-RISE REQUEST DURING HOT WATER SUPPLYPRESENTABSENTEXTERNAL APPARATUSESAIR-CONDITIONING REQUESTSCOOLING PRESENTMODE AMODE DHEATING PRESENTMODE BMODE ETHERMO-OFFMODE CSTOPOPERATION STOPCOMPLETE STOP

[0068] As shown in Table 1, the air-conditioning hot-water-supply system 1 preferably includes six or more operation modes that can be set via the remote controller 9 and are to be controlled by the controller 10, including at least a stop, for example. However, the heating operation in the air-conditioning operation may be omitted.

[0069] In Table 1, the air-conditioning request means that a user has set one of the air-conditioning operations including the cooling operation and the heating operation for the external apparatuses 5 (i.e., the radiator 6 and / or the indoor unit 7).

[0070] The term "cooling present" in the air-conditioning request indicates that the user has set the cooling operation and the room temperature or the like of the room having the external apparatuses 5 installed has not yet reached the set temperature for the cooling operation.

[0071] The term "heating present" in the air-conditioning requests indicates that the user has set the heating operation and the room temperature or the like of the room having the external apparatuses 5 installed has not yet reached the set temperature for the heating operation.

[0072] The term "thermo-OFF" in the air-conditioning requests indicates a state in which the user has set one of the air-conditioning operations including the cooling operation and the heating operation and the room temperature or the like of the room having the external apparatuses 5 installed has reached the set temperature for the cooling operation or the heating operation, i.e., a state in which the air-conditioning operation satisfies the air-conditioning conditions.

[0073] The term "complete stop" indicates a state in which none of the air-conditioning operations including the cooling operation and the heating operation is set by a user for the external apparatuses 5, i.e., a state in which the air-conditioning operation is not required.

[0074] The term "present" for the temperature-rise request during the hot water supply indicates a state in which a user has set the hot water supply operation and the stored hot water temperature in the hot water tank 12 has not reached the hot-water-supply set temperature.

[0075] In contrast, the term "absent" for the temperature-rise request during hot water supply indicates a state in which the hot water supply operation is not set by a user and hot water supply is not required or indicates a state in which the hot water supply operation is set by a user but the stored hot water temperature in the hot water tank 12 has reached the hot-water-supply set temperature.

[0076] On the basis of the combination of the operating states of the external apparatuses 5 and the hot water tank 12 and the user settings described above, the controller 10 determines one of six modes, including Mode A, Mode B, Mode C, Mode D, Mode E, and the stop.

[0077] Mode A is an operation mode to be selected when there is a cooling request for air conditioning in the external apparatus 5 and there is a temperature-rise request in the hot water supply operation. In Mode A, the controller 10 performs alternate switching between the cooling operation and the hot water supply operation at predetermined time intervals. The mode A is also referred to as a cooling / hot-water-supply switching operation or an alternating cooling and hot water supply operation.

[0078] Mode B is an operation mode to be selected when there is a heating request for air conditioning in the external apparatus 5 and there is a temperature-rise request in the hot water supply operation. In Mode B, the controller 10 performs alternate switching between the heating operation and the hot water supply operation at predetermined time intervals. Mode B is also referred to as a heating / hot-water-supply switching operation or an alternating heating and hot water supply operation.

[0079] Mode C is an operation mode in which the air-conditioning request in the external apparatuses 5 is in a thermo-OFF state or a complete stop state and the temperature-rise request is present in the hot water supply operation. In other words, Mode C is an operation mode in which only the hot water supply operation is performed.

[0080] Mode D is an operation mode in which the cooling request is present for the air-conditioning in the external apparatuses 5 and the temperature-rise request is absent in the hot water supply operation. In other words, Mode D is an operation mode in which only the cooling operation is performed.

[0081] Mode E is an operation mode in which the heating request is present for the air-conditioning in the external apparatuses 5 and the temperature-rise request is absent in the hot water supply operation. In other words, Mode E is an operation mode in which only the heating operation is performed.

[0082] Next, control of the heater 13 by the controller 10 will be described in more detail.

[0083] In the cooling / hot-water-supply switching operation in Mode A, it is alternately switched between the cooling operation and the hot water supply operation at predetermined time intervals. At this time, the cooled circulating water remains in the common path 41a of the heating-medium circulation circuit 41 when it is switched from the cooling operation to the hot water supply operation.

[0084] If the cooled circulating water is sent directly to the hot water tank 12 when it is switched from the cooling operation to the hot water supply operation, the stored hot water temperature in the hot water tank 12 significantly decreases due to the cooled circulating water. Since the pipes constituting the common path 41a of the heating-medium circulation circuit 41 are made of metal, these pipes remain at a low temperature due to the cooled circulating water, which further lowers the temperature of the circulating water. Consequently, it takes a longer time for the stored hot water temperature to reach the hot-water-supply set temperature.

[0085] Accordingly, when switching it from the cooling operation to the hot water supply operation, the controller 10 turns on the heater 13 for a predetermined period of time, thereby heating the circulating water, which passes through the forward pipe 81 provided with the heater 13 and flows into the hot water tank 12. This prevents the stored hot water temperature from being excessively lowered by the cooled circulating water remaining in the common path 41a when it is switched from the cooling operation to the hot water supply operation. Moreover, the time required for the stored hot water temperature to reach the hot-water-supply set temperature can be shortened. The predetermined period of time during which the heater 13 is turned on is preferably adjustable by a user. In such a case, the remote controller 9 may be configured such that the predetermined period of time during which the heater 13 is turned on can be set via its setting unit.

[0086] As shown in Fig. 2, in the air-conditioning hot-water-supply system 1 according to the present embodiment in which the heater 13 is turned on, when it is switched from the cooling operation to the hot water supply operation, the circulating water is heated by the heater 13 for a heater operation duration set value Tmh2 that is a predetermined period of time. In Fig. 2, the term "cooling" indicates the cooling operation, and the term "hot water supply" indicates the hot water supply operation. In addition, a cooling-operation duration set value in Mode A is defined as Tm1s, and a hot-water-supply-operation duration set value in Mode A is defined as Tm2s.

[0087] When the heater 13 is turned on, the water-heat-exchanger inlet temperature begins to rise. After the heater 13 is turned off, the water-heat-exchanger inlet temperature continues to rise gradually due to heating of the circulating water by the heat pump until the hot water supply operation ends. Thus, even if the cooled circulating water remaining in the common path 41a is delivered into the hot water tank 12, the decrease in the stored hot water temperature at the time of switching from the cooling operation to the hot water supply operation is suppressed as compared with the case where the heater 13 is not turned on. As a result, the air-conditioning hot-water-supply system 1 can shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature. In the case of Fig. 2, the stored hot water temperature reaches the hot-water-supply set temperature in the third cycle after starting Mode A as the operation mode. At this point, the hot water supply operation no longer requires a temperature increase, and the operation shifts from Mode A to Mode D in which only the cooling operation is performed.

[0088] With reference to Fig. 3, a description will be given of the case of switching from the cooling operation to the hot water supply operation in operation Mode A, regarding: (i): the operation of each component to be controlled by the controller 10; and (ii) the temporal changes in the stored hot water temperature and the water-heat-exchanger inlet temperature corresponding to the operation of each component. In the timing chart shown in the lower part of Fig. 3, the terms "hot water supply" and "cooling" for the operation states have the same meanings as in Fig. 2.

[0089] The term "heating of the four-way valve" refers to switching it to the refrigerant circulation path for heating the circulating water in the water heat exchanger 11, and the term "cooling" refers to switching it to the refrigerant circulation path for cooling the circulating water in the water heat exchanger 11.

[0090] The term "pump" refers to the first pump 45.

[0091] The term "hot water tank of the three-way valve" means that the circulation path of the circulating water is set to the side of the hot water tank 12 by the three-way valve 89.

[0092] The term "external apparatuses" means that the circulation path of the circulating water is set to the side of the external apparatuses 5 by the three-way valve 89.

[0093] These notations are used in the same manner as in the other figures described below.

[0094] At time t0, when the operation mode is switched from the cooling operation to the hot water supply operation, the compressor 23 is temporarily turned off. Thereafter, at time t1, the three-way valve 89 is already in a state where its flow path is switched from the side of the external apparatuses 5 to the side of the hot water tank 12, and the first pump 45 is turned on. Thus, at the time t1, even if the circulating water is not heated by the refrigerant in the water heat exchanger 11, the circulating water begins to be heated by the stored hot water in the hot water tank 12. That is, in the graph in the upper part of Fig. 3, the water-heat-exchanger inlet temperature begins to rise.

[0095] Subsequently, at time t2, the heater 13 is turned on, and the circulating water is further heated by the heater 13, thereby increasing the rate of rise of the water-heat-exchanger inlet temperature in the graph in the upper part of Fig. 3.

[0096] Subsequently, at time t3, the compressor 23 is turned on, the four-way valve 29 switches from the cooling side to the heating side almost simultaneously with this turn-on, and then the circulating water is heated by the refrigerant in the water heat exchanger 11, thereby further increasing the rate of rise of the water-heat-exchanger inlet temperature in the graph in the upper part of Fig. 3. That is, after the time t3, the circulating water is heated by three heat sources including: the stored hot water, the heater 13, and the refrigerant.

[0097] Under the condition where the water-heat-exchanger inlet temperature is lower than the stored hot water temperature as shown in the graph in the upper part of Fig. 3, the stored hot water continues to lose heat to the circulating water, and thus, the stored hot water temperature decreases slightly but continuously.

[0098] Referring further to Fig. 4, a description will be given of the changes in the rate of rise of the water-heat-exchanger inlet temperature in the case where the operation mode is switched from the cooling operation to the hot water supply operation and then the water-heat-exchanger inlet temperature becomes higher than the stored hot water temperature during the hot water supply operation. In the case of Fig. 4, the start of time interval T corresponds to the time t1 in Fig. 3.

[0099] As shown in Fig. 4, during the time interval T, the water-heat-exchanger inlet temperature is equal to or below the stored hot water temperature. Thus, the stored hot water continues to transfer heat to the circulating water, and the stored hot water temperature continues to decrease. After the end of the time interval T, the water-heat-exchanger inlet temperature becomes higher than the stored hot water temperature. As a result, the circulating water continues to transfer heat to the stored hot water such that the stored hot water temperature continues to rise and the rate of rise of the water-heat-exchanger inlet temperature decreases.

[0100] Referring back to Fig. 3, a description will be given of the timing at which the heater 13 is turned on with reference to the timing chart shown in the lower part of Fig. 3. As shown in the timing chart in Fig. 3, when the operation mode is switched from the cooling operation to the hot water supply operation, the compressor 23 turns off from its ON state, and thereafter, with a delay, the first pump 45 turns off from its ON state. The three-way valve 89 switches from the side of the external apparatuses 5 to the side of the hot water tank 12 when the first pump 45 is turned off. Subsequently, the first pump 45 is turned on again from its OFF state, and the heater 13 is turned on before the compressor 23 is turned on again.

[0101] In the hot water supply operation in Mode A to Mode C, the controller 10 turns on the heater 13 when the outside air temperature To is equal to or below a predetermined temperature. Although it depends on the characteristics of the refrigeration circuit including the refrigerant to be used, when the outside air temperature To falls to, for example, -10°C or below, the heat exchange efficiency between the air and the refrigerant in the air heat exchanger 25 is significantly reduced. Thus, it may not be possible to sufficiently heat the circulating water with the refrigerant in the water heat exchanger 11. In this case, the stored hot water in the hot water tank 12 is heated up to the hot-water-supply set temperature by turning on the heater 13 to further heat the circulating water, which prevents the time required for the stored hot water temperature in the hot water tank 12 to reach the hot-water-supply set temperature from becoming excessively long. Since the heater 13 is provided to compensate for insufficient heating by the heat pump as described above, it is also generally referred to as a backup heater.

[0102] Referring to Fig. 5 for reference, a description will be given of the timing of turning on the heater 13 when the outside air temperature To is equal to or below the predetermined temperature at the time of switching the operation mode from the heating operation to the hot water supply operation in operation Mode B. In this case, the heating-operation duration set value is defined as Tm3s, and the hot-water-supply-operation duration set value is defined as Tm4s.

[0103] After the elapse of the heating-operation duration set value Tm3s, only when the outside air temperature To is equal to or below the predetermined temperature after switching the operation mode from the heating operation to the hot water supply operation, the controller 10 turns on the heater 13 at the timing at which the first pump 45 is turned on. Thereafter, the compressor 23 is turned on. The controller 10 continues to keep the heater 13 turned on to heat the circulating water as long as the outside air temperature To does not exceed the predetermined temperature.

[0104] After the elapse of the hot-water-supply-operation duration set value Tm4s, the controller 10 turns off the heater 13 when the operation mode is switched from the hot water supply operation to the heating operation. Not only during the hot water supply operation but also during the heating operation, the heater 13 may be turned on if the outside air temperature To is at an even lower level.

[0105] The above-described series of operations in the air-conditioning hot-water-supply system 1 according to the present embodiment is executed by the controller 10 of the air-conditioning hot-water-supply system 1. The processing to be performed by the controller 10 will be described with reference to the flowcharts shown in Figs. 6 to 8. The signs and names shown in Figs. 6 to 8 are defined as follows.

[0106] A timer Tm1 measures a cooling-operation duration defined as a period of time during which the cooling operation is executed in Mode A. Mode A is an operation mode in which the operation mode is alternately switched between the cooling operation and the hot water supply operation at predetermined time intervals.

[0107] A timer Tm2 measures a hot-water-supply-operation duration defined as a period of time during which the hot water supply operation is executed in Mode A.

[0108] A timer Tm3 measures a heating-operation duration defined as a period of time during which the heating operation is executed in Mode B. Mode B is an operation mode in which the operation mode is alternately switched between the heating operation and the hot water supply operation at predetermined time intervals.

[0109] A timer Tm4 measures the hot-water-supply-operation duration defined as a period of time during which the hot water supply operation is executed in Mode B.

[0110] When Mode A is executed, the cooling-operation duration set value Tm1s is, for example, 30 minutes. When Mode A is executed, the hot-water-supply-operation duration set value Tm2s is, for example, 20 minutes. When Mode B is executed, the heating-operation duration set value Tm3s is, for example, 30 minutes. When Mode B is executed, the hot-water-supply-operation duration set value Tm4s is, for example, 15 minutes.

[0111] The compressor start-up delay time Tmc is the minimum time that must be ensured between the stop of the compressor 23 and its next start-up, and is, for example, 1 minute and 20 seconds. The compressor start-up delay time Tmc is provided to mitigate the pressure difference between the suction side and the discharge side when the compressor 23 is started.

[0112] The pump stop delay time Tmp1 of the first pump 45 is, for example, 20 seconds. When Mode A is executed, the pump start-up delay time Tmp2 of the first pump 45 is, for example, 25 seconds, which is obtained by adding 5 seconds to the pump stop delay time Tmp1. When Mode B is executed, the pump start-up delay time Tmp3 of the first pump 45 is, for example, 5 seconds.

[0113] The heater start-up delay time Tmh1 of the heater 13 is, for example, 30 seconds, which is obtained by adding 5 seconds to the pump start-up delay time Tmp2. That is, the heater 13 turns on 5 seconds after the first pump 45 is activated. The heater operation duration set value Tmh2 of the heater 13 is, for example, a value preset in the apparatus to approximately 3 to 5 minutes. The outside air temperature set value Tos is, for example, -10°C.

[0114] The stored hot water temperature Tt is detected by the hot-water-tank temperature sensor 69 and transmitted to the controller 10. The water-heat-exchanger inlet temperature Twi is detected by the inlet temperature sensor 52.

[0115] The compressor 23 is denoted as "COMP", and the four-way valve 29 is denoted as "FWV". Switching the four-way valve 29 to the heating position is denoted as "HEATING", and switching the four-way valve 29 to the cooling position is denoted as "COOLING". The first pump 45 is denoted as "P", and the three-way valve 89 is denoted as "TWV". Switching the three-way valve 89 to the side of the hot water tank 12 is denoted as "HWST", and switching the three-way valve 89 to the side of the external apparatuses 5 is denoted as "ED". The heater 13 is denoted as "H".

[0116] Step S1 is abbreviated as "S1". Steps S2 and thereafter are abbreviated in the same manner.

[0117] In Step S1 in Fig. 6, the controller 10 first determines whether there is a change in the operation mode or not. The operation mode is changed as shown in Table 1 depending on the user's operation, the statuses of the external apparatuses 5, and / or the status of the hot water tank 12. If there is a change in the operation mode (YES in Step S1), the routine proceeds to Step S2. If there is no change in the operation mode (NO in Step S1), the routine proceeds to Step S3.

[0118] In next Step S2 following the YES determination in Step S1, initialization processing is performed to change the operation mode by initializing the states of the control targets that are the compressor 23, the four-way valve 29, the first pump 45, the three-way valve 89, and the heater 13, and the routine then proceeds to Step S3. In the initialization processing, the compressor 23 is turned off, the four-way valve 29 is switched to the cooling position, the first pump 45 is turned off, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0119] In Step S3 following the NO determination in Step S1 or Step S2, the controller 10 determines the operation mode. If the operation mode is Mode A, the routine proceeds to Step S21 in Fig. 7. If the operation mode is Mode B, the routine proceeds to Step S51 in Fig. 8. If the operation mode is Mode C, the routine proceeds to Step S4. If the operation mode is Mode D, the routine proceeds to Step S5. If the operation mode is Mode E, the routine proceeds to Step S6. If the operation mode is the stop, the control targets have already been initialized to the stopped state in Step S2, and accordingly, the routine proceeds to Step S10.

[0120] In Step S4, that is, if the operation mode is Mode C, the compressor 23 is turned on, the four-way valve 29 is switched to the heating position, the first pump 45 is turned on, and the three-way valve 89 is switched to the side of the hot water tank 12.

[0121] In Step S5, that is, if the operation mode is Mode D, the compressor 23 is turned on, the four-way valve 29 is switched to the cooling position, the first pump 45 is turned on, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0122] In Step S6, that is, if the operation mode is Mode E, the compressor 23 is turned on, the four-way valve 29 is switched to the heating position, the first pump 45 is turned on, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0123] In Step S7 following Step S4, it is determined whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S7), the routine proceeds to Step S8 in which the heater 13 is turned on. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S7), the routine proceeds to Step S9 in which the heater 13 is turned off.

[0124] In Step S8, if the heater 13 has already been turned on in a step preceding Step S8, the ON state of the heater 13 is maintained.

[0125] Similarly, in Step S9, if the heater 13 has already been turned off in a step preceding Step S9, the OFF state of the heater 13 is maintained.

[0126] In Step S10 following Step S5, Step S6, Step S8, or Step S9, timers Tm1 to Tm4, which may be operating in the previous control, are reset to stop counting, and the routine returns to the start.

[0127] With reference to Fig. 7, the operation of each component in Mode A (i.e., the cooling / hot-water-supply switching operation) will be described.

[0128] In Step S21, the controller 10 first determines whether the timer Tm1 is operating or not. If the timer Tm1 is operating (YES in Step S21), the routine proceeds to Step S22. If the timer Tm1 is not operating (NO in Step S21), the routine proceeds to Step S37. Immediately after a change in the operation mode, each timer is reset in Step S10, and thus, the routine proceeds from Step S21 to Step S37.

[0129] In Step S22, it is determined whether the elapsed time of the operating timer Tm1 has reached or exceeded the cooling-operation duration set value Tm1s. If the elapsed time of the timer Tm1 has reached or exceeded the cooling-operation duration set value Tm1s (YES in Step S22), the routine proceeds to Step S23 to end the cooling operation and perform the hot water supply operation. If the elapsed time of the timer Tm1 is less than the cooling-operation duration set value Tm1s (NO in Step S22), the routine continues the cooling operation, returns to the beginning of Fig. 6, and proceeds to Step S1.

[0130] In Step S23, the controller 10 turns off the compressor 23 and the heater 13.

[0131] In subsequent Step S24, the timer Tm1 is reset to stop counting, and the timer Tm2 starts counting.

[0132] In subsequent Step S25, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1. If the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1 (YES in Step S25), the routine proceeds to Step S26. If the elapsed time of the timer Tm2 is less than the pump stop delay time Tmp1 (NO in Step S25), Step S25 is repeated to wait for the elapsed time of the timer Tm2.

[0133] In Step S26, the first pump 45 is turned off and the three-way valve 89 is switched to the side of the hot water tank 12.

[0134] In Step S27 following Step S26, the controller 10 determines whether the elapsed time of the timer Tm2 has reached or exceeded the pump start-up delay time Tmp2. If the elapsed time of the timer Tm2 has reached or exceeded the pump start-up delay time Tmp2 (YES in Step S27), the routine proceeds to Step S28 in which the first pump 45 is turned on. If the elapsed time of the timer Tm2 is less than the pump start-up delay time Tmp2 (NO in Step S27), Step S27 is repeated to wait for the elapsed time of the timer Tm2.

[0135] In Step S29 following Step S28, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the heater start-up delay time Tmh1. If the elapsed time of the timer Tm2 has reached or exceeded the heater start-up delay time Tmh1 (YES in Step S29), the routine proceeds to Step S30 in which the heater 13 is turned on. If the elapsed time of the timer Tm2 is less than the heater start-up delay time Tmh1 (NO in Step S29), Step S29 is repeated to wait for the elapsed time of the timer Tm2.

[0136] In Step S31 following Step S30, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the compressor start-up delay time Tmc. If the elapsed time of the timer Tm2 has reached or exceeded the compressor start-up delay time Tmc (YES in Step S31), the routine proceeds to Step S32 in which the compressor 23 is turned on and the four-way valve 29 is switched to the heating position. If the elapsed time of timer Tm2 is less than the compressor start-up delay time Tmc (NO in Step S31), Step S31 is repeated to wait for the elapsed time of the timer Tm2.

[0137] In Step S33 following Step S32, the controller 10 determines whether the elapsed time of the timer Tm2 has reached or exceeded the heater operation duration set value Tmh2. If the elapsed time of the timer Tm2 has reached or exceeded the heater operation duration set value Tmh2 (YES in Step S33), the routine proceeds to Step S34. If the elapsed time of the timer Tm2 is less than the heater operation duration set value Tmh2 (NO in Step S33), Step S33 is repeated to wait for the elapsed time of the timer Tm2.

[0138] In Step S34 following the YES determination in Step S33 or a NO determination in Step S38, the controller 10 determines whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S34), the routine proceeds to Step S35 in which the heater 13 is turned on or maintained in the ON state. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S34), the routine proceeds to Step S36 in which the heater 13 is turned off.

[0139] After Step S35 and Step S36, the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0140] If the determination in Step S21 is NO, that is, if the timer Tm1 is not operating, the routine proceeds to Step S37 in which the controller 10 determines whether the timer Tm2 is operating or not. If the timer Tm2 is operating (YES in Step S37), the routine proceeds to Step S38. If the timer Tm2 is not operating (NO in Step S37), the routine proceeds to Step S41. The case where the timer Tm2 is not operating in Step S37 corresponds to the state before the air-conditioning hot-water-supply system 1 starts Mode A, that is, the initial state when the air-conditioning hot-water-supply system 1 has just transitioned from another mode to Mode A.

[0141] In Step S38, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the hot-water-supply-operation duration set value Tm2s. If the elapsed time of the timer Tm2 has reached or exceeded the hot-water-supply-operation duration set value Tm2s (YES in Step S38), the routine proceeds to Step S39 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm2 is less than the hot-water-supply-operation duration set value Tm2s (NO in Step S38), the routine proceeds to Step S34.

[0142] In Step S40 following Step S39, the timer Tm2 is reset to stop counting. In subsequent Step S41, the timer Tm1 starts counting.

[0143] In subsequent Step S42, it is determined whether the elapsed time of the timer Tm1 has reached or exceeded the pump stop delay time Tmp1. If the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1 (YES in Step S42), in Step S43, the first pump 45 is turned off and the three-way valve 89 is switched to the side of the external apparatuses 5. If the elapsed time of the timer Tm1 is less than the pump stop delay time Tmp1 (NO in Step S42), Step S42 is repeated to wait for the elapsed time of the timer Tm1.

[0144] In Step S44 following Step S43, it is determined whether the elapsed time of the timer Tm1 has reached or exceeded the pump start-up delay time Tmp2. If the elapsed time of the timer Tm1 has reached or exceeded the pump start-up delay time Tmp2 (YES in Step S44), the routine proceeds to Step S45 in which the first pump 45 is turned on. If the elapsed time of the timer Tm1 is less than the pump start-up delay time Tmp2 (NO in Step S44), Step S44 is repeated to wait for the elapsed time of the timer Tm1.

[0145] In Step S46 following Step S45, the controller 10 determines whether the elapsed time of the timer Tm1 has reached or exceeded the compressor start-up delay time Tmc. If the elapsed time of the timer Tm1 has reached or exceeded the compressor start-up delay time Tmc (YES in Step S46), the routine proceeds to Step S47. If the elapsed time of the timer Tm1 is less than the compressor start-up delay time Tmc (NO in Step S46), Step S46 is repeated to wait for the elapsed time of the timer Tm1.

[0146] In Step S47, the compressor 23 is turned on, the four-way valve 29 is switched to the cooling position, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0147] Under the sequence control from Step S21 to Step S47, the cooling operation for the period defined by the cooling-operation duration set value Tm1s and the hot water supply operation for the period defined by the hot-water-supply-operation duration set value Tm2s are alternately repeated, and thereby, the operation of Mode A is executed.

[0148] With reference to Fig. 8, the operation of each component in Mode B (heating / hot-water-supply switching operation) will be described.

[0149] In Step S51, the controller 10 determines whether the timer Tm3 is operating or not. If the timer Tm3 is operating (YES in Step S51), the routine proceeds to Step S52. If the timer Tm3 is not operating (NO in Step S51), the routine proceeds to Step S61.

[0150] In Step S52, it is determined whether the elapsed time of the timer Tm3 has reached or exceeded the heating-operation duration set value Tm3s. If the elapsed time of the timer Tm3 has reached or exceeded the heating-operation duration set value Tm3s (YES in Step S52), the routine proceeds to Step S53 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm3 is less than the heating-operation duration set value Tm3s (NO in Step S52), the routine proceeds to Step S58.

[0151] In Step S54 following Step S53, the timer Tm3 is reset to stop counting, and the timer Tm4 starts counting.

[0152] In Step S55 following Step S54, the four-way valve 29 is maintained in the heating position, the first pump 45 is turned off, and the three-way valve 89 is switched to the side of the hot water tank 12.

[0153] In subsequent Step S56, it is determined whether the elapsed time of the timer Tm4 has reached or exceeded the pump start-up delay time Tmp3. If the elapsed time of the timer Tm4 has reached or exceeded the pump start-up delay time Tmp3 (YES in Step S56), the routine proceeds to Step S57 in which the first pump 45 is turned on. If the elapsed time of the timer Tm4 is less than the pump start-up delay time Tmp3 (NO in Step S56), Step S56 is repeated to wait for the elapsed time of the timer Tm4.

[0154] In Step S58 following the NO determination in Step S52 or Step S57, it is determined whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S58), the routine proceeds to Step S59 in which the heater 13 is turned on in response to the low outside air temperature, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S58), the routine proceeds to Step S60 in which the heater 13 is turned off or maintained in the OFF state, and then the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0155] If the timer Tm3 is not operating (NO in Step S51), in Step S61, it is determined whether the timer Tm4 is operating or not. If the timer Tm4 is operating (YES in Step S61), the routine proceeds to Step S62. If the timer Tm4 is not operating (NO in Step S61), the routine proceeds to Step S65. The case where the timer Tm4 is not operating corresponds to the state before the air-conditioning hot-water-supply system 1 starts Mode B, that is, the initial state when the air-conditioning hot-water-supply system 1 has just transitioned from another mode to Mode B.

[0156] In Step S62, the controller 10 determines whether the elapsed time of the timer Tm4 has reached or exceeded the hot-water-supply-operation duration set value Tm4s. If the elapsed time of the timer Tm4 has reached or exceeded the hot-water-supply-operation duration set value Tm4s (YES in Step S62), the routine proceeds to Step S63 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm4 is less than the hot-water-supply-operation duration set value Tm4s (NO in Step S62), the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0157] In Step S64 following Step S63, the timer Tm4 is reset to stop counting.

[0158] In Step S65 following the NO determination in Step S61 or Step S64, the timer Tm3 starts counting.

[0159] In Step S66 following Step S65, the four-way valve 29 is switched to the heating position or maintained in the heating position, the first pump 45 is turned off, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0160] In Step S67 following Step S66, the controller 10 determines whether the elapsed time of the timer Tm3 has reached or exceeded the pump start-up delay time Tmp3. If the elapsed time of the timer Tm3 has reached or exceeded the pump start-up delay time Tmp3 (YES in Step S67), the routine proceeds to Step S68 in which the first pump 45 is turned on, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1. If the elapsed time of the timer Tm3 is less than the pump start-up delay time Tmp3 (NO in Step S67), Step S67 is repeated to wait for the elapsed time of the timer Tm3.

[0161] In accordance with the control flows of Figs. 6 to 8 as described above, the controller 10 determines each operation mode and controls the respective components on the basis of the determination, whereby the air-conditioning hot-water-supply system 1 operates in the desired operation mode.

[0162] In the air-conditioning hot-water-supply system 1 of the present embodiment as described above, the controller 10 turns on the heater 13 for a predetermined period of time when switching it from the cooling operation to the hot water supply operation in operation Mode A. The heater 13 further heats the circulating water, which has been heated by the refrigerant in the water heat exchanger 11. That is, the air-conditioning hot-water-supply system 1 can increase the heating capacity for the circulating water serving as the heating medium by using the heater 13 in combination with the heat pump, prevent a decrease in the temperature of the stored hot water in the hot water tank 12, and shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature.

[0163] When switching it from the cooling operation to the hot water supply operation, the controller 10 turns on the heater 13 during the heater operation duration set value Tmh2 (Steps S29 to S33) after the elapse of the predetermined heater start-up delay time Tmh1. However, if the temperature of the circulating water is high, the power consumption of the heater 13 during that period may be wasted. Accordingly, Step S33 in Fig. 7 may be replaced with Step S33' to shorten the energization time of the heater 13. In Step S33', the heater 13 is turned off when the water-heat-exchanger inlet temperature Twi detected by the inlet temperature sensor 52 reaches or exceeds the stored hot water temperature Tt.

[0164] As described with reference to Fig. 4, once the water-heat-exchanger inlet temperature reaches or exceeds the stored hot water temperature, a decrease in the stored hot water temperature does not occur. Thus, the controller 10 turns off the heater 13 when the water-heat-exchanger inlet temperature reaches or exceeds the stored hot water temperature (point Q in Fig. 2), and shortens the energization time of the heater 13 while reducing the decrease in the stored hot water temperature, as compared with the case where the heater 13 is turned on for a predetermined time in Step S33. In this manner, the controller 10 suppresses an unnecessary rise in the temperature of the circulating water and reduces power consumption.

[0165] Although the first pump 45 and the heater 13 are turned on when it switches from the cooling operation to the hot water supply operation during the cooling / hot-water-supply switching operation in operation Mode A in the present embodiment, the first pump 45 and the heater 13 may similarly be turned on when it transitions from operation Mode D dedicated to the cooling operation to operation Mode C dedicated to the hot water supply operation, not limited to a running period of operation Mode A. However, in the actual operation of the air-conditioning hot-water-supply system 1, the possibility of transitioning from operation Mode D to operation Mode C is extremely low.

[0166] The heater 13 is provided primarily as a backup for assisting the heat pump in heating in order to: raise the temperature of the stored hot water in the hot water tank 12 to the hot-water-supply set temperature; and prevent the time required for the stored hot water temperature to reach the set temperature from becoming excessively long, even under a state where the heat output of the heat pump decreases due to a drop in the outside air temperature To during the hot water supply operation. Accordingly, it is configured such that the heater 13 is turned on when the outside air temperature To is equal to or below the predetermined outside air temperature set value Tos during the hot water supply operation (Step S34 to Step S36 in Fig. 7 and Step S58 to Step S60 in Fig. 8). This configuration avoids the so-called "hot water shortage", in which the stored hot water temperature in the hot water tank 12 falls and low-temperature water is delivered from faucets or showers.

[0167] Accordingly, the air-conditioning hot-water-supply system 1 of the present embodiment appropriately utilizes the heater 13 provided to assist the heating capacity of the heat pump when the outside air temperature To is equal to or below the predetermined outside air temperature set value Tos, and thereby achieves both of the following new effects: preventing a decrease in the stored hot water temperature in the hot water tank 12 during the transition from the cooling operation to the hot water supply operation; and shortening the time required for the stored hot water temperature to reach the hot-water-supply set temperature.

[0168] As another aspect of the air-conditioning hot-water-supply system 1, the outdoor unit 2 may include all the components that belong to the heat exchange unit 3 and are located on the side of the water heat exchanger 11 closer than the wavy lines P1 and P2 in Fig. 1. In this case, the outdoor unit 2 and the hot water tank 12 are connected only by piping through which the circulating water flows, and no piping for the refrigerant is connected. In this case, the piping through which the circulating water flows is exposed outdoors, and thus, there is a possibility that the circulating water in the piping may freeze while the air-conditioning hot-water-supply system 1 is stopped. Hence, when the outside air temperature To is low, the heater 13 and the first pump 45 provided in the outdoor unit 2 are operated, thereby preventing the circulating water in the outdoor piping from freezing under low outdoor temperature conditions.

[0169] As a further aspect of the air-conditioning hot-water-supply system 1, only the water heat exchanger 11 may be relocated from the heat exchange unit 3 to the outdoor unit 2. That is, the heat exchange unit 3 may be configured as an indoor unit including the expansion tank 49, the first pump 45, and the heater 13, which are located between the wavy lines P3 and P4 in Fig. 1, other than the water heat exchanger 11. In this case, the outdoor unit 2 and the indoor unit are connected by piping through which the circulating water flows, and thus, attention should be paid to the need for measures to prevent freezing of the circulating water in the piping, as in the above-described aspect. The hot water tank 12 may be disconnected from the heat exchange unit 3 at the portions of the wavy lines P5 and P6 in Fig. 1 so that the heat exchange unit 3 and the hot water tank 12 may be separated from each other, thereby allowing an increased degree of freedom in selecting installation locations for the heat exchange unit 3 and the hot water tank 12.

[0170] It may be configured such that: the position of the three-way valve 89 serving as a flow-path switching device for the circulating water is moved to the branching point Z; and the original position of the three-way valve 89 is changed to the branching (merging) point. That is, the positions of the branching point Z and the three-way valve 89 may be interchanged. In this case, the common path 41a is constituted by: the forward pipe 81 extending from the water heat exchanger 11 to the three-way valve 89; and the return pipe 83 extending from the branching point Z, which also serves as a merging point, to the water heat exchanger 11.

[0171] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.REFERENCE SIGNS LIST

[0172] 1air-conditioning hot-water-supply system 2outdoor unit 3heat exchange unit 5external apparatus 10controller 11water heat exchanger (heating-medium heat exchanger) 12hot water tank 13heater 14refrigerant piping 21refrigeration circuit 23compressor 25air heat exchanger 26outside-air temperature sensor (temperature sensor) 29four-way valve 41heating-medium circulation circuit 41acommon path 41bfirst heating-medium circulation circuit 41csecond heating-medium circulation circuit 45first pump 51outlet temperature sensor 52inlet temperature sensor 69hot-water-tank temperature sensor 89three-way valve (flow-path switching device)

Examples

Embodiment Construction

[0021]An air-conditioning hot-water-supply system according to the present embodiment will be described by referring to Figs. 1 to 8.

[0022]As shown in Fig. 1, the air-conditioning hot-water-supply system 1 includes: an outdoor unit 2 serving as a heat pump unit configured to exchange heat between the surrounding (outdoor) air and a refrigerant; a heat exchange unit 3 (i.e., hydro unit) accommodating a heating-medium heat exchanger 11 that exchanges heat between the refrigerant and a utilization-side heating medium; a plurality of external apparatuses 5 connected to the heat exchange unit 3; a remote controller 9 serving as an input device for receiving user operations; and a controller 10 configured to control respective components of the outdoor unit 2 and the heat exchange unit 3 on the basis of operations inputted to the remote controller 9. The external apparatuses 5 include at least one of a radiator 6 of a floor heating / cooling system and a fan coil unit 7 serving as an indoor...

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to an air-conditioning hot-water-supply system.BACKGROUND

[0002] A known heat source system can perform hot water supply, cooling and heating, and thermal storage and cooling using the same heat source. For example, such a heat source system uses a heat pump of a single heat source for performing: cooling and heating, thermal storage and cooling, hot water storage, hot water supply, and bath reheating. Furthermore, this heat source system controls these operations by a single control system.PRIOR ART DocumentPATENT DOCUMENT

[0003] [Patent Document 1] JP H07-253228 ASUMMARYPROBLEM TO BE SOLVED BY INVENTION

[0004] In an air-conditioning hot-water-supply system that includes a heat pump-type refrigeration cycle and performs air conditioning and hot water supply by using a heating medium such as water, the hot water stored in a hot water tank is heated by the heating medium that is heated by the heat pump. During a cooling operation or during a heating operation, the heating medium cooled or heated by the heat pump is supplied to air-conditioning equipment such as a fan coil unit provided indoors.

[0005] In such an air-conditioning hot-water-supply system, the cooling operation and the hot water supply operation may be set simultaneously during the summer. In this case, the heating medium is single, and accordingly, the cooling operation and the hot water supply operation cannot be performed at the same time. Hence, both indoor cooling and heating of the hot water stored in the hot water tank can be achieved by alternately performing the cooling operation and the heating operation by means of: (i) cooling and heating of the heating medium using the heat pump at predetermined time intervals; and (ii) switching of valves that change the flow path of the heating medium in conjunction therewith.

[0006] However, when it switches from the cooling operation to the hot water supply operation, the cooled heating medium (circulating water) remains in the path common to both the cooling path and the hot water supply path, through which the heating medium flows. In addition, during the cooling operation, pipes made of metal such as copper and located in the common path are also cooled and remain at a low temperature. Thus, when it switches from the cooling operation to the hot water supply operation, the cooled heating medium flows into the hot water tank, thereby lowering the temperature of the stored hot water in the hot water tank. In the following, the temperature of the stored hot water is abbreviated as "the stored hot water temperature".

[0007] Moreover, the cooling operation and the hot water supply operation are alternately switched at predetermined time intervals, and accordingly, the time available for heating the hot water tank during the hot water supply operation is limited. Consequently, each time it switches from the cooling operation to the hot water supply operation, the stored hot water temperature in the hot tank decreases and the time required for the stored hot water temperature to reach the hot-water-supply set temperature becomes longer.

[0008] The present invention aims to provide an air-conditioning hot-water-supply system that can suppress a decrease in the stored hot water temperature in the hot water tank so as to shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature at the time of switching from the cooling operation to the hot water supply operation.MEANS FOR SOLVING PROBLEM

[0009] To solve the above problems, an air-conditioning hot-water-supply system according to one embodiment of the present invention includes: a refrigeration circuit that includes a heating-medium heat exchanger configured to exchange heat between a refrigerant and a heating medium and can perform heating and cooling of the heating medium by the refrigerant in the heating-medium heat exchanger; a common path that is connected to a utilization side of the heating-medium heat exchanger, allows a cooled heating medium to flow through the common path during a cooling operation using the heating medium cooled by the refrigeration circuit, and allows a heated heating medium to flow through the common path during a hot water supply operation using the heating medium heated by the refrigeration circuit; a heater that heats the heating medium; and a controller that controls the refrigeration circuit and the heater, wherein the controller turns on the heater for a predetermined period of time at a time of switching from the cooling operation to the hot water supply operation.

[0010] Preferably, the air-conditioning hot-water-supply system according to the embodiment of the present invention further includes: a first heating-medium circulation circuit to which the common path is connected, and through which the cooled heating medium flows during the cooling operation; a second heating-medium circulation circuit to which the common path is connected, and through which the heated heating medium flows during the hot water supply operation; a flow-path switching device that is connected to the common path, the first heating-medium circulation circuit, and the second heating-medium circulation circuit and switches a flow of the heating medium from the common path to either the first heating-medium circulation circuit or the second heating-medium circulation circuit; and a pump that circulates the heating medium, wherein: the heater is provided in the common path or in the second heating-medium circulation circuit; and the controller is configured to further control the flow-path switching device and the pump.

[0011] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes: a hot water tank that is connected to the second heating-medium circulation circuit and exchanges heat between the heated heating medium and stored water; and a hot-water-tank temperature sensor that is provided in the hot water tank and detects the stored hot water temperature in the hot water tank.

[0012] Preferably, the air-conditioning hot-water-supply system according to the embodiment of the present invention further includes an inlet temperature sensor that is provided at an inlet of the heating medium of the heating-medium heat exchanger, wherein the predetermined period of time is set to be a period of time until a temperature of the heating medium detected by the inlet temperature sensor reaches or exceeds the stored hot water temperature detected by the hot-water-tank temperature sensor.

[0013] The heater and the pump of the air-conditioning hot-water-supply system according to the embodiment of the present invention are preferably provided in the common path.

[0014] The refrigeration circuit of the air-conditioning hot-water-supply system according to the embodiment of the present invention preferably includes a compressor configured to compress the refrigerant. The controller is preferably configured to temporarily turn off the pump at a time of switching from the cooling operation to the hot water supply operation, and turn on the heater after turning on the pump again and before turning on the compressor.

[0015] The refrigeration circuit of the air-conditioning hot-water-supply system according to the embodiment of the present invention preferably includes: an air heat exchanger configured to exchange heat between the refrigerant and ambient air; and a temperature sensor configured to detect an ambient temperature at a location where the air heat exchanger is installed. The controller is preferably configured to turn on the heater when the ambient temperature detected by the temperature sensor is equal to or below a predetermined temperature during the hot water supply operation.

[0016] The controller of the air-conditioning hot-water-supply system according to the embodiment of the present invention is preferably configured to perform switching between the cooling operation and the hot water supply operation alternately at predetermined time intervals, when simultaneous requests for the cooling operation and the hot water supply operation occur.

[0017] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, and the heater.

[0018] The air-conditioning hot-water-supply system according to the embodiment of the present invention preferably further includes a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, the heater, and the hot water tank.EFFECTS OF INVENTION

[0019] The present invention can provide an air-conditioning hot-water-supply system that can suppress a decrease in the stored hot water temperature in the hot water tank so as to shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature at the time of switching from the cooling operation to the hot water supply operation.BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a system configuration diagram of an air-conditioning hot-water-supply system according to one embodiment of the present invention. Fig. 2 is a conceptual diagram illustrating time-series changes in a stored hot water temperature, a water-heat-exchanger inlet temperature, and an operation of a heater during a cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 3 is a combination of: (i) a timing chart illustrating an operation of each component during the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention; and (ii) a diagram illustrating the corresponding time variations of the water-heat-exchanger inlet temperature and the stored hot water temperature. Fig. 4 is a diagram illustrating time variations of the stored hot water temperature and the water-heat-exchanger inlet temperature during the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 5 is a timing chart illustrating an operation of each component during a heating / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 6 is a diagram illustrating a control flow of each operation mode in the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 7 is a diagram illustrating a control flow of the cooling / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. Fig. 8 is a diagram illustrating a control flow of the heating / hot-water-supply switching operation of the air-conditioning hot-water-supply system according to the embodiment of the present invention. DETAILED DESCRIPTION

[0021] An air-conditioning hot-water-supply system according to the present embodiment will be described by referring to Figs. 1 to 8.

[0022] As shown in Fig. 1, the air-conditioning hot-water-supply system 1 includes: an outdoor unit 2 serving as a heat pump unit configured to exchange heat between the surrounding (outdoor) air and a refrigerant; a heat exchange unit 3 (i.e., hydro unit) accommodating a heating-medium heat exchanger 11 that exchanges heat between the refrigerant and a utilization-side heating medium; a plurality of external apparatuses 5 connected to the heat exchange unit 3; a remote controller 9 serving as an input device for receiving user operations; and a controller 10 configured to control respective components of the outdoor unit 2 and the heat exchange unit 3 on the basis of operations inputted to the remote controller 9. The external apparatuses 5 include at least one of a radiator 6 of a floor heating / cooling system and a fan coil unit 7 serving as an indoor unit of an air-conditioning system. It is sufficient that the number of the external apparatuses 5 is one or more.

[0023] Although water is used as the utilization-side heating medium in the present embodiment, the utilization-side heating medium is not limited to water and may be another fluid such as an antifreeze solution. Hereinafter, the utilization-side heating medium is simply referred to as the heating medium, circulating water, or water, and the heating-medium heat exchanger 11 is referred to as the water heat exchanger 11. As to the refrigerant, any suitable refrigerant, such as R410A, R32, and CO 2 , may be used.

[0024] The air-conditioning hot-water-supply system 1 includes a refrigeration circuit 21 that circulates the refrigerant through the outdoor unit 2 and the heat exchange unit 3. The refrigeration circuit 21 includes: a compressor 23 that compresses and discharges the refrigerant; a four-way valve 29 that switches the direction of the refrigerant flow; an air heat exchanger 25 that functions as an evaporator and a condenser for exchanging heat between the refrigerant and the surrounding air; an expansion valve 27; the water heat exchanger 11 that functions as a condenser and an evaporator for exchanging heat between the refrigerant and the circulating water; and refrigerant piping 14 that connects these components to circulate the refrigerant. The water heat exchanger 11 is a plate-type heat exchanger or a heat exchanger such as a double-pipe type. The refrigeration circuit 21 may also be referred to as a heat pump.

[0025] Of the components of the refrigeration circuit 21, the compressor 23, the four-way valve 29, the air heat exchanger 25, the expansion valve 27, and a part of the refrigerant piping 14 are accommodated in the outdoor unit 2. The heat exchange unit 3 accommodates: a part of the refrigerant piping 14; a heater 13; a hot water tank 12; piping that serves as a flow path for the circulating water; a first pump 45 and a second pump 91, both of which circulate the circulating water as described below; a flow-path switching device 89 that switches the flow path of the circulating water; various sensors; and the controller 10. Water to be stored in the hot water tank 12 having a capacity of about 100 to 300 liters is generally tap water to be supplied from outside through a water supply pipe and is heated by the circulating water. Hot water heated in the hot water tank 12, i.e., stored hot water, is supplied to hot-water supply destinations such as a washroom, a kitchen, and a bathroom. The controller 10 may be accommodated not only in the heat exchange unit 3 but also in the outdoor unit 2 or in the remote controller 9. Additionally or alternatively, a plurality of controllers 10 may be distributed among the heat exchange unit 3, the outdoor unit 2, and / or the remote controller 9 so that the respective controllers 10 operate in coordination with each other.

[0026] In general, the outdoor unit 2 is installed outdoors, and the heat exchange unit 3 is installed indoors. The outdoor unit 2 and the heat exchange unit 3 are connected to each other via connecting pipes 15 and 16 of the refrigerant piping 14 and communication lines (not shown). That is, only the refrigerant flows between the outdoor unit 2 and the heat exchange unit 3, and thus, the air-conditioning hot-water-supply system 1 does not require any outdoor piping through which the circulating water flows. Accordingly, the air-conditioning hot-water-supply system 1 can avoid freezing of the circulating water in the outdoor piping under low ambient temperature conditions.

[0027] During the cooling operation, the air-conditioning hot-water-supply system 1 cools the circulating water with the refrigeration circuit 21, and circulates the circulating water having a temperature of 7°C to 25°C to the external apparatuses 5, for example.

[0028] During the heating operation and during a hot water supply operation, the air-conditioning hot-water-supply system 1 heats the circulating water with the heat pump to obtain the circulating water at a first temperature, for example, 20°C to 65°C.

[0029] During the heating operation, the air-conditioning hot-water-supply system 1 circulates the circulating water at the first temperature to the external apparatuses 5 without causing the circulating water to pass through the hot water tank 12. During the hot water supply operation, the air-conditioning hot-water-supply system 1 circulates the circulating water at the first temperature to the hot water tank 12 without causing the circulating water to pass through the external apparatuses 5.

[0030] During the hot water supply operation, the air-conditioning hot-water-supply system 1 can combine heating of the circulating water with the heat pump and heating of the circulating water with the heater 13, which is provided downstream of the water heat exchanger 11 in the heat exchange unit 3, and thereby can circulate the circulating water at a second temperature higher than the first temperature, for example, about 65°C, to the hot water tank 12. As a result, the air-conditioning hot-water-supply system 1 can store hot water at about 65°C in the hot water tank 12. When the ambient temperature around the outdoor unit 2, i.e., the outside air temperature, is extremely low, for example, below -20°C, heating of the circulating water by the heat pump becomes insufficient, and thus, the heater 13 is turned on to promote heating of the circulating water.

[0031] During the hot water supply operation, the air-conditioning hot-water-supply system 1 performs so-called boiling-up, i.e., heating of the water stored in the hot water tank 12, by using the circulating water circulating through the heat exchange unit 3.

[0032] The air-conditioning hot-water-supply system 1 having the above-described configuration includes, as its basic functions, the following: (1) A function of circulating the refrigerant between the outdoor unit 2 and the heat exchange unit 3 and thereby exchanging heat between the refrigerant and the circulating water in the water heat exchanger 11 of the heat exchange unit 3. (2) A function of circulating either the cooled circulating water or the heated circulating water between the heat exchange unit 3 and the plurality of external apparatuses 5 and thereby air-conditioning the rooms in which the external apparatuses 5 are installed. (3) A function of circulating the heated circulating water within the hot water tank 12 to heat the water stored therein to heat and produce hot water and thereby supplying the hot water to hot-water destinations as needed.

[0033] The outdoor unit 2 is provided with an outside-air temperature sensor 26. The outside-air temperature sensor 26 detects an outside air temperature To, which is defined as the upstream air temperature before passing through the air heat exchanger 25 and is the ambient temperature of the air heat exchanger 25, and outputs the outside air temperature To to the controller 10.

[0034] The compressor 23 compresses the refrigerant and discharges the refrigerant at an elevated pressure. It is preferred that the compressor 23 can vary its operating frequency by known inverter control through an inverter device (not shown). Increasing the rotational speed of the compressor 23 increases the amount of heat to be transferred to the high-temperature side, whereas decreasing the rotational speed reduces the amount of heat to be transferred to the high-temperature side. In this case, the controller 10 detects an air-conditioning load or a hot-water-supply load, and adjusts the operating frequency of the inverter device depending on the detection result, thereby enabling it to exhibit an appropriate refrigeration capacity corresponding to the load state.

[0035] The expansion valve 27 is, for example, an electronic expansion valve, such as a pulse motor valve (PMV), with an electrically adjustable degree of opening.

[0036] The four-way valve 29 switches the flow direction of the refrigerant that circulates through the compressor 23, the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11. When the circulating water is heated in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 to flow through the water heat exchanger 11, the expansion valve 27, and the air heat exchanger 25 in this order. The solid arrows in Fig. 1 indicate this flow of the refrigerant. In this case, the water heat exchanger 11 functions as a condenser.

[0037] The refrigerant having passed through the water heat exchanger 11 returns to the outdoor unit 2 via the connecting pipe 16, passes through the expansion valve 27 to be depressurized, and becomes a low-pressure gas-liquid two-phase refrigerant. Thereafter, the low-pressure gas-liquid two-phase refrigerant is sent to the air heat exchanger 25. The air heat exchanger 25 is ventilated with the outside air by a blower (not shown). The low-pressure gas-liquid two-phase refrigerant is heated by the outside air passing through the air heat exchanger 25 and becomes a gas-phase refrigerant. In this case, the air heat exchanger 25 functions as an evaporator. After passing through the air heat exchanger 25 and becoming a gas-phase refrigerant, the refrigerant returns to the compressor 23. The evaporator is also referred to as a heat absorber, and the condenser is also referred to as a radiator.

[0038] When the circulating water is cooled in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 to flow through the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11 in this order. The dashed arrows in Fig. 1 indicate this flow of the refrigerant. In this case, the high-temperature and high-pressure refrigerant discharged from the compressor 23 is sent to the air heat exchanger 25 via the four-way valve 29. The high-temperature and high-pressure refrigerant is cooled by the outside air passing through the air heat exchanger 25 and becomes a high-pressure liquid-phase refrigerant. In this case, the air heat exchanger 25 functions as a condenser.

[0039] The refrigerant having passed through the air heat exchanger 25 passes through the expansion valve 27 to be depressurized, thereby becomes a low-pressure gas-liquid two-phase refrigerant, is sent to the heat exchange unit 3 via the connecting pipe 16, and then enters the water heat exchanger 11. The water heat exchanger 11 cools the circulating water flowing through the water heat exchanger 11 by the refrigerant passing through the water heat exchanger 11. The refrigerant that has cooled the circulating water in the water heat exchanger 11 is heated and becomes a low-pressure gas-phase refrigerant. In this case, the water heat exchanger 11 functions as an evaporator. After passing through the water heat exchanger 11 and becoming gas-phase, the refrigerant returns to the outdoor unit 2 via the connecting pipe 15 and is then drawn into the compressor 23.

[0040] The heat exchange unit 3 includes a part of a heating-medium circulation circuit 41 that is a water circuit configured to: (i) circulate the circulating water subjected to heat exchange in the water heat exchanger 11 between the water heat exchanger 11 and the plurality of external apparatuses 5 during the cooling operation and during the heating operation; and (ii) circulate the circulating water heated in the water heat exchanger 11 between the water heat exchanger 11 and the hot water tank 12 during the hot water supply operation. The flow direction of the circulating water is selectively switched either toward the side of the external apparatuses 5 or toward the side of the hot water tank 12 by the flow-path switching device 89.

[0041] The heating-medium circulation circuit 41 is provided with: an outlet temperature sensor 51 installed at the outlet of the circulating water of the water heat exchanger 11; an inlet temperature sensor 52 installed at the inlet of the circulating water of the water heat exchanger 11; and a flow sensor 53 configured to measure a flow rate of the circulating water. The outputs of the outlet temperature sensor 51, the inlet temperature sensor 52, and the flow sensor 53 are supplied to the controller 10 in the same manner as the outputs of the other sensors. The circulating water circulates in one direction through the heating-medium circulation circuit 41 by the operation of the first pump 45. The heating-medium circulation circuit 41 includes a circulating-water pipe 43. The circulating-water pipe 43 and other pipes through which the circulating water flows are formed of metal pipes, such as a copper pipe and an iron pipe.

[0042] The outlet temperature sensor 51 detects the temperature of the circulating water immediately after heat exchange by the water heat exchanger 11 and outputs the detected temperature to the controller 10. The inlet temperature sensor 52 detects the temperature of the circulating water immediately before heat exchange by the water heat exchanger 11 and outputs the detected temperature to the controller 10. The temperature detected by the inlet temperature sensor 52 corresponds to the temperature of the circulating water returned after heat exchange with the indoor air by the plurality of external apparatuses 5 during the air-conditioning operation for heating or cooling, and corresponds to the temperature of the circulating water returned after heat exchange with feed water in the hot water tank 12 during the hot water supply operation. Hereinafter, the temperature of the circulating water detected by the inlet temperature sensor 52 is referred to as the water-heat-exchanger inlet temperature.

[0043] During the hot water supply operation, the circulating water heated by the water heat exchanger 11 is drawn by the driven first pump 45 and delivered through the circulating-water pipe 43 to the hot water tank 12. The circulating water exchanges heat with the feed water in the hot water tank 12 to heat the feed water. The circulating water, decreased in temperature due to the heat exchange, is returned to the water heat exchanger 11 so as to be heated by the refrigerant circulating in the refrigeration circuit 21, and then circulates again within the heating-medium circulation circuit 41.

[0044] The hot water tank 12 includes: a tank 61 that is made of stainless steel and can store the feed water; a feed water pipe 65 that supplies the feed water such as city water into the tank 61 through an outlet 63 of the feed water pipe 65 provided at the lower portion of the tank 61; a coil 67 that circulates the circulating water within the tank 61 and indirectly heats the feed water in the tank 61; a hot water tank temperature sensor 69 that detects the stored hot water temperature in the tank 61; a hot-water supply pipe 71 that guides the stored water heated in the tank 61 to the outside of the tank 61; and an insulation member 73 that covers the outer surface of the tank 61.

[0045] The tank 61 is a sealed container except for the feed water pipe 65 and the hot-water supply pipe 71. When the stored hot water is delivered to the hot-water supply destination connected to the hot-water supply pipe 71, water is supplied into the tank 61 through the outlet 63 of the feed water pipe 65 to compensate for the discharged amount of the hot water. Thus, the interior of the tank 61 is always maintained full of water. The hot-water supply pipe 71 for supplying the stored hot water in the tank 61 is provided in an upper end plate 75, which constitutes the top of the tank 61. In general, the hot water tank 12 supplies the stored hot water in the tank 61 to the destination connected to the hot-water supply pipe 71 by pushing out the stored hot water in the tank 61 using the water pressure of the tap water in the supply pipe connected to the feed water pipe 65.

[0046] The coil 67 includes: a circulating-water inlet pipe 67a that penetrates the upper end plate 75 in the vertical direction and extends linearly downward within the tank 61; a helical portion 67b that is helically wound following the circulating-water inlet pipe 67a; and a circulating-water return pipe 67c that extends linearly upward within the tank 61 from the end of the helical portion 67b and penetrates the upper end plate 75 in the vertical direction. The space around the coil 67 located in the tank 61 is filled with water. The feed water and / or the stored hot water are heated by heat exchange between: (i) the high-temperature circulating water circulating within the coil 67; and (ii) the feed water and / or the stored hot water in the hot water tank 12.

[0047] The hot-water-tank temperature sensor 69 detects a representative value of the stored hot water temperature in the tank 61. The output of the hot-water-tank temperature sensor 69 is inputted to the controller 10. The hot-water-tank temperature sensor 69 is provided in the interior of a thin tubular temperature-sensor holder 77, which protrudes downward from the upper end plate 75. The temperature-sensor holder 77 extends from a location suitable for detecting the stored hot water temperature in the tank 61, for example, from the upper end plate 75, downward toward the central portion of the tank 61. Specifically, the inner circumferential surface of the temperature-sensor holder 77 is connected to the outer surface of the tank 61, and the outer circumferential surface of the temperature-sensor holder 77 is connected to the inner surface of the tank 61. The hot-water-tank temperature sensor 69 detects the stored hot water temperature transmitted from the outer surface to the inner surface of the temperature-sensor holder 77.

[0048] The insulation member 73 is provided around the tank 61 and suppresses direct heat radiation to the atmosphere, thereby preventing a decrease in the stored hot water temperature in the tank 61. The material of the insulation member 73 is a foamed polystyrene material or a foamed urethane material having higher thermal insulation performance than the foamed polystyrene material. A vacuum insulation material having even higher thermal insulation performance may also be used. The lower portion of the tank 61 is supplied with tap water, which is unheated feed water, from the outlet 63 of the feed water pipe 65 provided at the lower portion, and has no insulation material because the need for heat retention is low.

[0049] Focusing on the circulation path of the circulating water, the heating-medium circulation circuit 41 includes: an external circulating-water pipe 87 that is located farther from the water heat exchanger 11 than the circulating-water pipe 43 and circulates the circulating water through the external apparatuses 5; a branching point Z where the circulating water flowing through the circulating-water pipe 43 branches off toward the external circulating-water pipe 87; and the flow-path switching device 89 that switches the circulation path of the circulating water to either the side of the hot water tank 12 or the side of the external apparatuses 5, in addition to the circulating-water pipe 43.

[0050] The circulating-water pipe 43 includes: a forward pipe 81 that directs the circulating water heated by the water heat exchanger 11 to the coil 67 of the hot water tank 12 or to the external apparatuses 5; and a return pipe 83 that directs the circulating water decreased in temperature after heating the feed water in the tank 61 or the circulating water having undergone heat exchange in the external apparatuses 5 to the water heat exchanger 11.

[0051] In the forward pipe 81, a first pump 45 configured to circulate the circulating water, a heater 13 configured to heat the circulating water passing therethrough, and an expansion tank 49 configured to absorb expansion (i.e., an increase in volume) of the heated circulating water are provided in this order. The expansion tank 49 is independently connected to a pipe branched from the forward pipe 81. The flow sensor 53 is provided in the middle of the return pipe 83.

[0052] The external circulating-water pipe 87 includes: an external forward pipe 95 configured to guide the circulating water toward the external apparatuses 5 in one of two directions branched from the branching point Z located at a terminal end of the forward pipe 81; and an external return pipe 97 configured to return the circulating water used in the external apparatuses 5 to the return pipe 83. The circulating-water inlet pipe 67a configured to introduce the circulating water into the hot water tank 12 is connected to the other branch from the branching point Z.

[0053] The external forward pipe 95 branches into two directions: a first forward pipe 95a that supplies the circulating water to the radiator 6 at an intermediate portion; and a second forward pipe 95b that supplies the circulating water to the indoor unit 7. In the external return pipe 97, a first return pipe 97a for returning the circulating water from the radiator 6 and a second return pipe 97b for returning the circulating water from the indoor unit 7 merge.

[0054] A mixing valve 93 and the second pump 91 are sequentially connected to the second forward pipe 95b. One end of the mixing valve 93 is connected to an intermediate portion of the second return pipe 97b. The opening degree of the mixing valve 93 is adjusted to vary the amount of mixing between a portion of the circulating water used by the indoor unit 7 and the circulating water supplied to the indoor unit 7, thereby controlling the temperature of the circulating water flowing through the indoor unit 7 to satisfy the temperature requirement that has been set for the indoor unit 7. The second pump 91 operates only when the indoor unit 7 requests the cooling operation or the heating operation and the requested operation can be performed, and remains stopped during other operating states, such as during the hot water supply operation. The circulating water used in the external apparatuses 5 is returned to the return pipe 83 of the heating-medium circulation circuit 41 between the hot water tank 12 and the water heat exchanger 11 through the external return pipe 97 of the external circulating-water pipe 87.

[0055] Although the air-conditioning hot-water-supply system 1 can supply the cooled or heated circulating water to two external apparatuses 5 (the radiator 6 and the indoor unit 7) in the present embodiment, the number of the external apparatus 5 may be only one.

[0056] At the branching point Z, the circulating water from the forward pipe 81 flows into the external forward pipe 95 during the cooling operation and during the heating operations, and flows into the other branch, i.e., the circulating-water inlet pipe 67a, during the hot water supply operation.

[0057] Although various forms such as a combination of a plurality of valves can be adopted as the flow-path switching device 89, in the present embodiment, a description will be given of a case of using a three-way valve 89, which allows the simplest piping configuration. The three-way valve 89 includes an outlet configured to be always open and two inlets configured to be switched such that only one of the two inlets is connected to the outlet. The outlet of the three-way valve 89 is connected to the return pipe 83, one of its inlets is connected to the external return pipe 97, and the other inlet is connected to the circulating-water return pipe 67c extending from the interior of the hot water tank 12. Accordingly, the flow path of the circulating water can be directed to either the side of the hot water tank 12 or the side of the external apparatuses 5 by switching the connection direction of the three-way valve 89 between the time of the cooling and heating operations and the time of the hot water supply operation.

[0058] As described above, the heating-medium circulation circuit 41 includes: a circulation path for the circulating water that circulates on the side of the external apparatuses 5; and another circulation path for the circulating water that circulates on the side of the hot water tank 12. These circulation paths share a common portion. The common path 41a serving as this common portion includes the following two segments: (i) the forward pipe 81 that is connected to the outlet pipe on the utilization side of the water heat exchanger 11 and extends from the water heat exchanger 11 to the branching point Z; and (ii) the return pipe 83 that is connected to the inlet pipe on the utilization side of the water heat exchanger 11 and extends from the three-way valve 89 to the water heat exchanger 11.

[0059] The portion of the circulation path for the circulating water circulating on the side of the external apparatuses 5 other than the common path 41a is hereinafter referred to as the first heating-medium circulation circuit 41b. The portion of the circulation path for the circulating water circulating on the side of the hot water tank 12 other than the common path 41a is hereinafter referred to as the second heating-medium circulation circuit 41c.

[0060] Accordingly, the outlet of the three-way valve 89 is connected to the common path 41a, one of the inlets of the three-way valve 89 is connected to the first heating-medium circulation circuit 41b, and the other inlet of the three-way valve 89 is connected to the second heating-medium circulation circuit 41c. The first heating-medium circulation circuit 41b substantially corresponds to the path of the external circulating-water pipe 87. Specifically, the second heating-medium circulation circuit 41c is a path extending from the branching point Z through the circulating-water inlet pipe 67a, the helical portion 67b within the hot water tank 12, and the circulating-water return pipe 67c to the three-way valve 89.

[0061] In accordance with instructions from the controller 10, the air-conditioning hot-water-supply system 1 can selectively switch the circulation path of the circulating water either toward the first heating-medium circulation circuit 41b or toward the second heating-medium circulation circuit 41c at predetermined time intervals in a time-division manner using the three-way valve 89 in such a manner that: (i) the cooling operation of the external apparatuses 5 and the hot water supply operation of the hot water tank 12 are concurrently performed; and / or (ii) the hot water supply operation and the heating operation of the external apparatuses 5 are concurrently performed.

[0062] The common path 41a includes the heater 13, the expansion tank 49, and the first pump 45 provided in the forward pipe 81. The heater 13 may be relocated to the second heating-medium circulation circuit 41c. In this case, however, the heater 13 cannot be used as an auxiliary heat source during the heating operation of the external apparatuses 5.

[0063] At least one remote controller 9 is provided. The remote controller(s) 9 may include a remote controller provided in the outdoor unit 2, another remote controller provided in the heat exchange unit 3, and still another remote controller installed on an indoor wall (not shown), for example.

[0064] The remote controller 9 includes: a setting unit (not shown) that serves as an input interface for setting the set temperature of the circulation water and / or the operation mode of the air-conditioning hot-water-supply system 1; and a display (not shown) that displays the contents of the settings as operation conditions of the outdoor unit 2, the heat exchange unit 3, and the external apparatuses 5 and the operating states of them. The remote controller 9 transmits the following three items to the controller 10 as control signals, which are set by the user via the setting unit: (i) the set temperature of the circulating water to be circulated to the external apparatuses 5; (ii) the set temperature for boiling water in the hot water tank 12 (i.e., the hot-water-supply set temperature); and (iii) the operation mode of the air-conditioning hot-water-supply system 1.

[0065] The controller 10 includes a microprocessor (not shown) and a storage device (not shown) that stores various parameters and computation programs to be executed by the microprocessor. The controller 10 reads the various control programs from an auxiliary storage device into a main storage device, and executes the control programs read into the main storage device in a central processing unit within the microprocessor. The controller 10 executes sequence control on the basis of: (i) instructions from the remote controller 9; and (ii) detection values from various sensors, such as the outlet temperature sensor 51, the inlet temperature sensor 52, and the flow sensor 53. The controller 10 may be configured with a logic circuit to execute the sequence control.

[0066] On the basis of the control signals received from the remote controller 9 via a wired or wireless communication line and outputs from various sensors, the controller 10 executes the operation control of the air-conditioning hot-water-supply system 1 including: (i) control of the four-way valve 29 and the compressor 23 of the refrigeration circuit 21; and (ii) control of the first pump 45, the three-way valve 89, and the heater 13 in the heat exchange unit 3. For example, the controller 10 executes the operation control of the air-conditioning hot-water-supply system 1 such that the temperature detected by the hot-water-tank temperature sensor 69 within the tank 61 becomes the hot-water-supply set temperature of the hot water tank 12.

[0067] The controller 10 switches the path of the circulating water from the common path 41a to either the first heating-medium circulation circuit 41b on the side of the external apparatuses 5 or the second heating-medium circulation circuit 41c on the side of the hot water tank 12 by controlling the switching of the three-way valve 89. Furthermore, the controller 10 alternately switches the circulation path of the circulating water between the side of the external apparatuses 5 and the side of the hot water tank 12, thereby enabling both boiling of the stored hot water in the hot water tank 12 and supply of the circulating water to the external apparatuses 5. The remote controller 9 allows a user to set an operation mode of switching these operating states via the operation unit. [Table 1]HOT WATER TANKTEMPERATURE-RISE REQUEST DURING HOT WATER SUPPLYPRESENTABSENTEXTERNAL APPARATUSESAIR-CONDITIONING REQUESTSCOOLING PRESENTMODE AMODE DHEATING PRESENTMODE BMODE ETHERMO-OFFMODE CSTOPOPERATION STOPCOMPLETE STOP

[0068] As shown in Table 1, the air-conditioning hot-water-supply system 1 preferably includes six or more operation modes that can be set via the remote controller 9 and are to be controlled by the controller 10, including at least a stop, for example. However, the heating operation in the air-conditioning operation may be omitted.

[0069] In Table 1, the air-conditioning request means that a user has set one of the air-conditioning operations including the cooling operation and the heating operation for the external apparatuses 5 (i.e., the radiator 6 and / or the indoor unit 7).

[0070] The term "cooling present" in the air-conditioning request indicates that the user has set the cooling operation and the room temperature or the like of the room having the external apparatuses 5 installed has not yet reached the set temperature for the cooling operation.

[0071] The term "heating present" in the air-conditioning requests indicates that the user has set the heating operation and the room temperature or the like of the room having the external apparatuses 5 installed has not yet reached the set temperature for the heating operation.

[0072] The term "thermo-OFF" in the air-conditioning requests indicates a state in which the user has set one of the air-conditioning operations including the cooling operation and the heating operation and the room temperature or the like of the room having the external apparatuses 5 installed has reached the set temperature for the cooling operation or the heating operation, i.e., a state in which the air-conditioning operation satisfies the air-conditioning conditions.

[0073] The term "complete stop" indicates a state in which none of the air-conditioning operations including the cooling operation and the heating operation is set by a user for the external apparatuses 5, i.e., a state in which the air-conditioning operation is not required.

[0074] The term "present" for the temperature-rise request during the hot water supply indicates a state in which a user has set the hot water supply operation and the stored hot water temperature in the hot water tank 12 has not reached the hot-water-supply set temperature.

[0075] In contrast, the term "absent" for the temperature-rise request during hot water supply indicates a state in which the hot water supply operation is not set by a user and hot water supply is not required or indicates a state in which the hot water supply operation is set by a user but the stored hot water temperature in the hot water tank 12 has reached the hot-water-supply set temperature.

[0076] On the basis of the combination of the operating states of the external apparatuses 5 and the hot water tank 12 and the user settings described above, the controller 10 determines one of six modes, including Mode A, Mode B, Mode C, Mode D, Mode E, and the stop.

[0077] Mode A is an operation mode to be selected when there is a cooling request for air conditioning in the external apparatus 5 and there is a temperature-rise request in the hot water supply operation. In Mode A, the controller 10 performs alternate switching between the cooling operation and the hot water supply operation at predetermined time intervals. The mode A is also referred to as a cooling / hot-water-supply switching operation or an alternating cooling and hot water supply operation.

[0078] Mode B is an operation mode to be selected when there is a heating request for air conditioning in the external apparatus 5 and there is a temperature-rise request in the hot water supply operation. In Mode B, the controller 10 performs alternate switching between the heating operation and the hot water supply operation at predetermined time intervals. Mode B is also referred to as a heating / hot-water-supply switching operation or an alternating heating and hot water supply operation.

[0079] Mode C is an operation mode in which the air-conditioning request in the external apparatuses 5 is in a thermo-OFF state or a complete stop state and the temperature-rise request is present in the hot water supply operation. In other words, Mode C is an operation mode in which only the hot water supply operation is performed.

[0080] Mode D is an operation mode in which the cooling request is present for the air-conditioning in the external apparatuses 5 and the temperature-rise request is absent in the hot water supply operation. In other words, Mode D is an operation mode in which only the cooling operation is performed.

[0081] Mode E is an operation mode in which the heating request is present for the air-conditioning in the external apparatuses 5 and the temperature-rise request is absent in the hot water supply operation. In other words, Mode E is an operation mode in which only the heating operation is performed.

[0082] Next, control of the heater 13 by the controller 10 will be described in more detail.

[0083] In the cooling / hot-water-supply switching operation in Mode A, it is alternately switched between the cooling operation and the hot water supply operation at predetermined time intervals. At this time, the cooled circulating water remains in the common path 41a of the heating-medium circulation circuit 41 when it is switched from the cooling operation to the hot water supply operation.

[0084] If the cooled circulating water is sent directly to the hot water tank 12 when it is switched from the cooling operation to the hot water supply operation, the stored hot water temperature in the hot water tank 12 significantly decreases due to the cooled circulating water. Since the pipes constituting the common path 41a of the heating-medium circulation circuit 41 are made of metal, these pipes remain at a low temperature due to the cooled circulating water, which further lowers the temperature of the circulating water. Consequently, it takes a longer time for the stored hot water temperature to reach the hot-water-supply set temperature.

[0085] Accordingly, when switching it from the cooling operation to the hot water supply operation, the controller 10 turns on the heater 13 for a predetermined period of time, thereby heating the circulating water, which passes through the forward pipe 81 provided with the heater 13 and flows into the hot water tank 12. This prevents the stored hot water temperature from being excessively lowered by the cooled circulating water remaining in the common path 41a when it is switched from the cooling operation to the hot water supply operation. Moreover, the time required for the stored hot water temperature to reach the hot-water-supply set temperature can be shortened. The predetermined period of time during which the heater 13 is turned on is preferably adjustable by a user. In such a case, the remote controller 9 may be configured such that the predetermined period of time during which the heater 13 is turned on can be set via its setting unit.

[0086] As shown in Fig. 2, in the air-conditioning hot-water-supply system 1 according to the present embodiment in which the heater 13 is turned on, when it is switched from the cooling operation to the hot water supply operation, the circulating water is heated by the heater 13 for a heater operation duration set value Tmh2 that is a predetermined period of time. In Fig. 2, the term "cooling" indicates the cooling operation, and the term "hot water supply" indicates the hot water supply operation. In addition, a cooling-operation duration set value in Mode A is defined as Tm1s, and a hot-water-supply-operation duration set value in Mode A is defined as Tm2s.

[0087] When the heater 13 is turned on, the water-heat-exchanger inlet temperature begins to rise. After the heater 13 is turned off, the water-heat-exchanger inlet temperature continues to rise gradually due to heating of the circulating water by the heat pump until the hot water supply operation ends. Thus, even if the cooled circulating water remaining in the common path 41a is delivered into the hot water tank 12, the decrease in the stored hot water temperature at the time of switching from the cooling operation to the hot water supply operation is suppressed as compared with the case where the heater 13 is not turned on. As a result, the air-conditioning hot-water-supply system 1 can shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature. In the case of Fig. 2, the stored hot water temperature reaches the hot-water-supply set temperature in the third cycle after starting Mode A as the operation mode. At this point, the hot water supply operation no longer requires a temperature increase, and the operation shifts from Mode A to Mode D in which only the cooling operation is performed.

[0088] With reference to Fig. 3, a description will be given of the case of switching from the cooling operation to the hot water supply operation in operation Mode A, regarding: (i): the operation of each component to be controlled by the controller 10; and (ii) the temporal changes in the stored hot water temperature and the water-heat-exchanger inlet temperature corresponding to the operation of each component. In the timing chart shown in the lower part of Fig. 3, the terms "hot water supply" and "cooling" for the operation states have the same meanings as in Fig. 2.

[0089] The term "heating of the four-way valve" refers to switching it to the refrigerant circulation path for heating the circulating water in the water heat exchanger 11, and the term "cooling" refers to switching it to the refrigerant circulation path for cooling the circulating water in the water heat exchanger 11.

[0090] The term "pump" refers to the first pump 45.

[0091] The term "hot water tank of the three-way valve" means that the circulation path of the circulating water is set to the side of the hot water tank 12 by the three-way valve 89.

[0092] The term "external apparatuses" means that the circulation path of the circulating water is set to the side of the external apparatuses 5 by the three-way valve 89.

[0093] These notations are used in the same manner as in the other figures described below.

[0094] At time t0, when the operation mode is switched from the cooling operation to the hot water supply operation, the compressor 23 is temporarily turned off. Thereafter, at time t1, the three-way valve 89 is already in a state where its flow path is switched from the side of the external apparatuses 5 to the side of the hot water tank 12, and the first pump 45 is turned on. Thus, at the time t1, even if the circulating water is not heated by the refrigerant in the water heat exchanger 11, the circulating water begins to be heated by the stored hot water in the hot water tank 12. That is, in the graph in the upper part of Fig. 3, the water-heat-exchanger inlet temperature begins to rise.

[0095] Subsequently, at time t2, the heater 13 is turned on, and the circulating water is further heated by the heater 13, thereby increasing the rate of rise of the water-heat-exchanger inlet temperature in the graph in the upper part of Fig. 3.

[0096] Subsequently, at time t3, the compressor 23 is turned on, the four-way valve 29 switches from the cooling side to the heating side almost simultaneously with this turn-on, and then the circulating water is heated by the refrigerant in the water heat exchanger 11, thereby further increasing the rate of rise of the water-heat-exchanger inlet temperature in the graph in the upper part of Fig. 3. That is, after the time t3, the circulating water is heated by three heat sources including: the stored hot water, the heater 13, and the refrigerant.

[0097] Under the condition where the water-heat-exchanger inlet temperature is lower than the stored hot water temperature as shown in the graph in the upper part of Fig. 3, the stored hot water continues to lose heat to the circulating water, and thus, the stored hot water temperature decreases slightly but continuously.

[0098] Referring further to Fig. 4, a description will be given of the changes in the rate of rise of the water-heat-exchanger inlet temperature in the case where the operation mode is switched from the cooling operation to the hot water supply operation and then the water-heat-exchanger inlet temperature becomes higher than the stored hot water temperature during the hot water supply operation. In the case of Fig. 4, the start of time interval T corresponds to the time t1 in Fig. 3.

[0099] As shown in Fig. 4, during the time interval T, the water-heat-exchanger inlet temperature is equal to or below the stored hot water temperature. Thus, the stored hot water continues to transfer heat to the circulating water, and the stored hot water temperature continues to decrease. After the end of the time interval T, the water-heat-exchanger inlet temperature becomes higher than the stored hot water temperature. As a result, the circulating water continues to transfer heat to the stored hot water such that the stored hot water temperature continues to rise and the rate of rise of the water-heat-exchanger inlet temperature decreases.

[0100] Referring back to Fig. 3, a description will be given of the timing at which the heater 13 is turned on with reference to the timing chart shown in the lower part of Fig. 3. As shown in the timing chart in Fig. 3, when the operation mode is switched from the cooling operation to the hot water supply operation, the compressor 23 turns off from its ON state, and thereafter, with a delay, the first pump 45 turns off from its ON state. The three-way valve 89 switches from the side of the external apparatuses 5 to the side of the hot water tank 12 when the first pump 45 is turned off. Subsequently, the first pump 45 is turned on again from its OFF state, and the heater 13 is turned on before the compressor 23 is turned on again.

[0101] In the hot water supply operation in Mode A to Mode C, the controller 10 turns on the heater 13 when the outside air temperature To is equal to or below a predetermined temperature. Although it depends on the characteristics of the refrigeration circuit including the refrigerant to be used, when the outside air temperature To falls to, for example, -10°C or below, the heat exchange efficiency between the air and the refrigerant in the air heat exchanger 25 is significantly reduced. Thus, it may not be possible to sufficiently heat the circulating water with the refrigerant in the water heat exchanger 11. In this case, the stored hot water in the hot water tank 12 is heated up to the hot-water-supply set temperature by turning on the heater 13 to further heat the circulating water, which prevents the time required for the stored hot water temperature in the hot water tank 12 to reach the hot-water-supply set temperature from becoming excessively long. Since the heater 13 is provided to compensate for insufficient heating by the heat pump as described above, it is also generally referred to as a backup heater.

[0102] Referring to Fig. 5 for reference, a description will be given of the timing of turning on the heater 13 when the outside air temperature To is equal to or below the predetermined temperature at the time of switching the operation mode from the heating operation to the hot water supply operation in operation Mode B. In this case, the heating-operation duration set value is defined as Tm3s, and the hot-water-supply-operation duration set value is defined as Tm4s.

[0103] After the elapse of the heating-operation duration set value Tm3s, only when the outside air temperature To is equal to or below the predetermined temperature after switching the operation mode from the heating operation to the hot water supply operation, the controller 10 turns on the heater 13 at the timing at which the first pump 45 is turned on. Thereafter, the compressor 23 is turned on. The controller 10 continues to keep the heater 13 turned on to heat the circulating water as long as the outside air temperature To does not exceed the predetermined temperature.

[0104] After the elapse of the hot-water-supply-operation duration set value Tm4s, the controller 10 turns off the heater 13 when the operation mode is switched from the hot water supply operation to the heating operation. Not only during the hot water supply operation but also during the heating operation, the heater 13 may be turned on if the outside air temperature To is at an even lower level.

[0105] The above-described series of operations in the air-conditioning hot-water-supply system 1 according to the present embodiment is executed by the controller 10 of the air-conditioning hot-water-supply system 1. The processing to be performed by the controller 10 will be described with reference to the flowcharts shown in Figs. 6 to 8. The signs and names shown in Figs. 6 to 8 are defined as follows.

[0106] A timer Tm1 measures a cooling-operation duration defined as a period of time during which the cooling operation is executed in Mode A. Mode A is an operation mode in which the operation mode is alternately switched between the cooling operation and the hot water supply operation at predetermined time intervals.

[0107] A timer Tm2 measures a hot-water-supply-operation duration defined as a period of time during which the hot water supply operation is executed in Mode A.

[0108] A timer Tm3 measures a heating-operation duration defined as a period of time during which the heating operation is executed in Mode B. Mode B is an operation mode in which the operation mode is alternately switched between the heating operation and the hot water supply operation at predetermined time intervals.

[0109] A timer Tm4 measures the hot-water-supply-operation duration defined as a period of time during which the hot water supply operation is executed in Mode B.

[0110] When Mode A is executed, the cooling-operation duration set value Tm1s is, for example, 30 minutes. When Mode A is executed, the hot-water-supply-operation duration set value Tm2s is, for example, 20 minutes. When Mode B is executed, the heating-operation duration set value Tm3s is, for example, 30 minutes. When Mode B is executed, the hot-water-supply-operation duration set value Tm4s is, for example, 15 minutes.

[0111] The compressor start-up delay time Tmc is the minimum time that must be ensured between the stop of the compressor 23 and its next start-up, and is, for example, 1 minute and 20 seconds. The compressor start-up delay time Tmc is provided to mitigate the pressure difference between the suction side and the discharge side when the compressor 23 is started.

[0112] The pump stop delay time Tmp1 of the first pump 45 is, for example, 20 seconds. When Mode A is executed, the pump start-up delay time Tmp2 of the first pump 45 is, for example, 25 seconds, which is obtained by adding 5 seconds to the pump stop delay time Tmp1. When Mode B is executed, the pump start-up delay time Tmp3 of the first pump 45 is, for example, 5 seconds.

[0113] The heater start-up delay time Tmh1 of the heater 13 is, for example, 30 seconds, which is obtained by adding 5 seconds to the pump start-up delay time Tmp2. That is, the heater 13 turns on 5 seconds after the first pump 45 is activated. The heater operation duration set value Tmh2 of the heater 13 is, for example, a value preset in the apparatus to approximately 3 to 5 minutes. The outside air temperature set value Tos is, for example, -10°C.

[0114] The stored hot water temperature Tt is detected by the hot-water-tank temperature sensor 69 and transmitted to the controller 10. The water-heat-exchanger inlet temperature Twi is detected by the inlet temperature sensor 52.

[0115] The compressor 23 is denoted as "COMP", and the four-way valve 29 is denoted as "FWV". Switching the four-way valve 29 to the heating position is denoted as "HEATING", and switching the four-way valve 29 to the cooling position is denoted as "COOLING". The first pump 45 is denoted as "P", and the three-way valve 89 is denoted as "TWV". Switching the three-way valve 89 to the side of the hot water tank 12 is denoted as "HWST", and switching the three-way valve 89 to the side of the external apparatuses 5 is denoted as "ED". The heater 13 is denoted as "H".

[0116] Step S1 is abbreviated as "S1". Steps S2 and thereafter are abbreviated in the same manner.

[0117] In Step S1 in Fig. 6, the controller 10 first determines whether there is a change in the operation mode or not. The operation mode is changed as shown in Table 1 depending on the user's operation, the statuses of the external apparatuses 5, and / or the status of the hot water tank 12. If there is a change in the operation mode (YES in Step S1), the routine proceeds to Step S2. If there is no change in the operation mode (NO in Step S1), the routine proceeds to Step S3.

[0118] In next Step S2 following the YES determination in Step S1, initialization processing is performed to change the operation mode by initializing the states of the control targets that are the compressor 23, the four-way valve 29, the first pump 45, the three-way valve 89, and the heater 13, and the routine then proceeds to Step S3. In the initialization processing, the compressor 23 is turned off, the four-way valve 29 is switched to the cooling position, the first pump 45 is turned off, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0119] In Step S3 following the NO determination in Step S1 or Step S2, the controller 10 determines the operation mode. If the operation mode is Mode A, the routine proceeds to Step S21 in Fig. 7. If the operation mode is Mode B, the routine proceeds to Step S51 in Fig. 8. If the operation mode is Mode C, the routine proceeds to Step S4. If the operation mode is Mode D, the routine proceeds to Step S5. If the operation mode is Mode E, the routine proceeds to Step S6. If the operation mode is the stop, the control targets have already been initialized to the stopped state in Step S2, and accordingly, the routine proceeds to Step S10.

[0120] In Step S4, that is, if the operation mode is Mode C, the compressor 23 is turned on, the four-way valve 29 is switched to the heating position, the first pump 45 is turned on, and the three-way valve 89 is switched to the side of the hot water tank 12.

[0121] In Step S5, that is, if the operation mode is Mode D, the compressor 23 is turned on, the four-way valve 29 is switched to the cooling position, the first pump 45 is turned on, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0122] In Step S6, that is, if the operation mode is Mode E, the compressor 23 is turned on, the four-way valve 29 is switched to the heating position, the first pump 45 is turned on, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0123] In Step S7 following Step S4, it is determined whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S7), the routine proceeds to Step S8 in which the heater 13 is turned on. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S7), the routine proceeds to Step S9 in which the heater 13 is turned off.

[0124] In Step S8, if the heater 13 has already been turned on in a step preceding Step S8, the ON state of the heater 13 is maintained.

[0125] Similarly, in Step S9, if the heater 13 has already been turned off in a step preceding Step S9, the OFF state of the heater 13 is maintained.

[0126] In Step S10 following Step S5, Step S6, Step S8, or Step S9, timers Tm1 to Tm4, which may be operating in the previous control, are reset to stop counting, and the routine returns to the start.

[0127] With reference to Fig. 7, the operation of each component in Mode A (i.e., the cooling / hot-water-supply switching operation) will be described.

[0128] In Step S21, the controller 10 first determines whether the timer Tm1 is operating or not. If the timer Tm1 is operating (YES in Step S21), the routine proceeds to Step S22. If the timer Tm1 is not operating (NO in Step S21), the routine proceeds to Step S37. Immediately after a change in the operation mode, each timer is reset in Step S10, and thus, the routine proceeds from Step S21 to Step S37.

[0129] In Step S22, it is determined whether the elapsed time of the operating timer Tm1 has reached or exceeded the cooling-operation duration set value Tm1s. If the elapsed time of the timer Tm1 has reached or exceeded the cooling-operation duration set value Tm1s (YES in Step S22), the routine proceeds to Step S23 to end the cooling operation and perform the hot water supply operation. If the elapsed time of the timer Tm1 is less than the cooling-operation duration set value Tm1s (NO in Step S22), the routine continues the cooling operation, returns to the beginning of Fig. 6, and proceeds to Step S1.

[0130] In Step S23, the controller 10 turns off the compressor 23 and the heater 13.

[0131] In subsequent Step S24, the timer Tm1 is reset to stop counting, and the timer Tm2 starts counting.

[0132] In subsequent Step S25, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1. If the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1 (YES in Step S25), the routine proceeds to Step S26. If the elapsed time of the timer Tm2 is less than the pump stop delay time Tmp1 (NO in Step S25), Step S25 is repeated to wait for the elapsed time of the timer Tm2.

[0133] In Step S26, the first pump 45 is turned off and the three-way valve 89 is switched to the side of the hot water tank 12.

[0134] In Step S27 following Step S26, the controller 10 determines whether the elapsed time of the timer Tm2 has reached or exceeded the pump start-up delay time Tmp2. If the elapsed time of the timer Tm2 has reached or exceeded the pump start-up delay time Tmp2 (YES in Step S27), the routine proceeds to Step S28 in which the first pump 45 is turned on. If the elapsed time of the timer Tm2 is less than the pump start-up delay time Tmp2 (NO in Step S27), Step S27 is repeated to wait for the elapsed time of the timer Tm2.

[0135] In Step S29 following Step S28, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the heater start-up delay time Tmh1. If the elapsed time of the timer Tm2 has reached or exceeded the heater start-up delay time Tmh1 (YES in Step S29), the routine proceeds to Step S30 in which the heater 13 is turned on. If the elapsed time of the timer Tm2 is less than the heater start-up delay time Tmh1 (NO in Step S29), Step S29 is repeated to wait for the elapsed time of the timer Tm2.

[0136] In Step S31 following Step S30, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the compressor start-up delay time Tmc. If the elapsed time of the timer Tm2 has reached or exceeded the compressor start-up delay time Tmc (YES in Step S31), the routine proceeds to Step S32 in which the compressor 23 is turned on and the four-way valve 29 is switched to the heating position. If the elapsed time of timer Tm2 is less than the compressor start-up delay time Tmc (NO in Step S31), Step S31 is repeated to wait for the elapsed time of the timer Tm2.

[0137] In Step S33 following Step S32, the controller 10 determines whether the elapsed time of the timer Tm2 has reached or exceeded the heater operation duration set value Tmh2. If the elapsed time of the timer Tm2 has reached or exceeded the heater operation duration set value Tmh2 (YES in Step S33), the routine proceeds to Step S34. If the elapsed time of the timer Tm2 is less than the heater operation duration set value Tmh2 (NO in Step S33), Step S33 is repeated to wait for the elapsed time of the timer Tm2.

[0138] In Step S34 following the YES determination in Step S33 or a NO determination in Step S38, the controller 10 determines whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S34), the routine proceeds to Step S35 in which the heater 13 is turned on or maintained in the ON state. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S34), the routine proceeds to Step S36 in which the heater 13 is turned off.

[0139] After Step S35 and Step S36, the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0140] If the determination in Step S21 is NO, that is, if the timer Tm1 is not operating, the routine proceeds to Step S37 in which the controller 10 determines whether the timer Tm2 is operating or not. If the timer Tm2 is operating (YES in Step S37), the routine proceeds to Step S38. If the timer Tm2 is not operating (NO in Step S37), the routine proceeds to Step S41. The case where the timer Tm2 is not operating in Step S37 corresponds to the state before the air-conditioning hot-water-supply system 1 starts Mode A, that is, the initial state when the air-conditioning hot-water-supply system 1 has just transitioned from another mode to Mode A.

[0141] In Step S38, it is determined whether the elapsed time of the timer Tm2 has reached or exceeded the hot-water-supply-operation duration set value Tm2s. If the elapsed time of the timer Tm2 has reached or exceeded the hot-water-supply-operation duration set value Tm2s (YES in Step S38), the routine proceeds to Step S39 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm2 is less than the hot-water-supply-operation duration set value Tm2s (NO in Step S38), the routine proceeds to Step S34.

[0142] In Step S40 following Step S39, the timer Tm2 is reset to stop counting. In subsequent Step S41, the timer Tm1 starts counting.

[0143] In subsequent Step S42, it is determined whether the elapsed time of the timer Tm1 has reached or exceeded the pump stop delay time Tmp1. If the elapsed time of the timer Tm2 has reached or exceeded the pump stop delay time Tmp1 (YES in Step S42), in Step S43, the first pump 45 is turned off and the three-way valve 89 is switched to the side of the external apparatuses 5. If the elapsed time of the timer Tm1 is less than the pump stop delay time Tmp1 (NO in Step S42), Step S42 is repeated to wait for the elapsed time of the timer Tm1.

[0144] In Step S44 following Step S43, it is determined whether the elapsed time of the timer Tm1 has reached or exceeded the pump start-up delay time Tmp2. If the elapsed time of the timer Tm1 has reached or exceeded the pump start-up delay time Tmp2 (YES in Step S44), the routine proceeds to Step S45 in which the first pump 45 is turned on. If the elapsed time of the timer Tm1 is less than the pump start-up delay time Tmp2 (NO in Step S44), Step S44 is repeated to wait for the elapsed time of the timer Tm1.

[0145] In Step S46 following Step S45, the controller 10 determines whether the elapsed time of the timer Tm1 has reached or exceeded the compressor start-up delay time Tmc. If the elapsed time of the timer Tm1 has reached or exceeded the compressor start-up delay time Tmc (YES in Step S46), the routine proceeds to Step S47. If the elapsed time of the timer Tm1 is less than the compressor start-up delay time Tmc (NO in Step S46), Step S46 is repeated to wait for the elapsed time of the timer Tm1.

[0146] In Step S47, the compressor 23 is turned on, the four-way valve 29 is switched to the cooling position, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0147] Under the sequence control from Step S21 to Step S47, the cooling operation for the period defined by the cooling-operation duration set value Tm1s and the hot water supply operation for the period defined by the hot-water-supply-operation duration set value Tm2s are alternately repeated, and thereby, the operation of Mode A is executed.

[0148] With reference to Fig. 8, the operation of each component in Mode B (heating / hot-water-supply switching operation) will be described.

[0149] In Step S51, the controller 10 determines whether the timer Tm3 is operating or not. If the timer Tm3 is operating (YES in Step S51), the routine proceeds to Step S52. If the timer Tm3 is not operating (NO in Step S51), the routine proceeds to Step S61.

[0150] In Step S52, it is determined whether the elapsed time of the timer Tm3 has reached or exceeded the heating-operation duration set value Tm3s. If the elapsed time of the timer Tm3 has reached or exceeded the heating-operation duration set value Tm3s (YES in Step S52), the routine proceeds to Step S53 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm3 is less than the heating-operation duration set value Tm3s (NO in Step S52), the routine proceeds to Step S58.

[0151] In Step S54 following Step S53, the timer Tm3 is reset to stop counting, and the timer Tm4 starts counting.

[0152] In Step S55 following Step S54, the four-way valve 29 is maintained in the heating position, the first pump 45 is turned off, and the three-way valve 89 is switched to the side of the hot water tank 12.

[0153] In subsequent Step S56, it is determined whether the elapsed time of the timer Tm4 has reached or exceeded the pump start-up delay time Tmp3. If the elapsed time of the timer Tm4 has reached or exceeded the pump start-up delay time Tmp3 (YES in Step S56), the routine proceeds to Step S57 in which the first pump 45 is turned on. If the elapsed time of the timer Tm4 is less than the pump start-up delay time Tmp3 (NO in Step S56), Step S56 is repeated to wait for the elapsed time of the timer Tm4.

[0154] In Step S58 following the NO determination in Step S52 or Step S57, it is determined whether the outside air temperature To is equal to or below the outside air temperature set value Tos. If the outside air temperature To is equal to or below the outside air temperature set value Tos (YES in Step S58), the routine proceeds to Step S59 in which the heater 13 is turned on in response to the low outside air temperature, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1. If the outside air temperature To is above the outside air temperature set value Tos (NO in Step S58), the routine proceeds to Step S60 in which the heater 13 is turned off or maintained in the OFF state, and then the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0155] If the timer Tm3 is not operating (NO in Step S51), in Step S61, it is determined whether the timer Tm4 is operating or not. If the timer Tm4 is operating (YES in Step S61), the routine proceeds to Step S62. If the timer Tm4 is not operating (NO in Step S61), the routine proceeds to Step S65. The case where the timer Tm4 is not operating corresponds to the state before the air-conditioning hot-water-supply system 1 starts Mode B, that is, the initial state when the air-conditioning hot-water-supply system 1 has just transitioned from another mode to Mode B.

[0156] In Step S62, the controller 10 determines whether the elapsed time of the timer Tm4 has reached or exceeded the hot-water-supply-operation duration set value Tm4s. If the elapsed time of the timer Tm4 has reached or exceeded the hot-water-supply-operation duration set value Tm4s (YES in Step S62), the routine proceeds to Step S63 in which the compressor 23 and the heater 13 are turned off. If the elapsed time of the timer Tm4 is less than the hot-water-supply-operation duration set value Tm4s (NO in Step S62), the routine returns to the beginning of Fig. 6 and proceeds to Step S1.

[0157] In Step S64 following Step S63, the timer Tm4 is reset to stop counting.

[0158] In Step S65 following the NO determination in Step S61 or Step S64, the timer Tm3 starts counting.

[0159] In Step S66 following Step S65, the four-way valve 29 is switched to the heating position or maintained in the heating position, the first pump 45 is turned off, the three-way valve 89 is switched to the side of the external apparatuses 5, and the heater 13 is turned off.

[0160] In Step S67 following Step S66, the controller 10 determines whether the elapsed time of the timer Tm3 has reached or exceeded the pump start-up delay time Tmp3. If the elapsed time of the timer Tm3 has reached or exceeded the pump start-up delay time Tmp3 (YES in Step S67), the routine proceeds to Step S68 in which the first pump 45 is turned on, and the routine returns to the beginning of Fig. 6 and proceeds to Step S1. If the elapsed time of the timer Tm3 is less than the pump start-up delay time Tmp3 (NO in Step S67), Step S67 is repeated to wait for the elapsed time of the timer Tm3.

[0161] In accordance with the control flows of Figs. 6 to 8 as described above, the controller 10 determines each operation mode and controls the respective components on the basis of the determination, whereby the air-conditioning hot-water-supply system 1 operates in the desired operation mode.

[0162] In the air-conditioning hot-water-supply system 1 of the present embodiment as described above, the controller 10 turns on the heater 13 for a predetermined period of time when switching it from the cooling operation to the hot water supply operation in operation Mode A. The heater 13 further heats the circulating water, which has been heated by the refrigerant in the water heat exchanger 11. That is, the air-conditioning hot-water-supply system 1 can increase the heating capacity for the circulating water serving as the heating medium by using the heater 13 in combination with the heat pump, prevent a decrease in the temperature of the stored hot water in the hot water tank 12, and shorten the time required for the stored hot water temperature to reach the hot-water-supply set temperature.

[0163] When switching it from the cooling operation to the hot water supply operation, the controller 10 turns on the heater 13 during the heater operation duration set value Tmh2 (Steps S29 to S33) after the elapse of the predetermined heater start-up delay time Tmh1. However, if the temperature of the circulating water is high, the power consumption of the heater 13 during that period may be wasted. Accordingly, Step S33 in Fig. 7 may be replaced with Step S33' to shorten the energization time of the heater 13. In Step S33', the heater 13 is turned off when the water-heat-exchanger inlet temperature Twi detected by the inlet temperature sensor 52 reaches or exceeds the stored hot water temperature Tt.

[0164] As described with reference to Fig. 4, once the water-heat-exchanger inlet temperature reaches or exceeds the stored hot water temperature, a decrease in the stored hot water temperature does not occur. Thus, the controller 10 turns off the heater 13 when the water-heat-exchanger inlet temperature reaches or exceeds the stored hot water temperature (point Q in Fig. 2), and shortens the energization time of the heater 13 while reducing the decrease in the stored hot water temperature, as compared with the case where the heater 13 is turned on for a predetermined time in Step S33. In this manner, the controller 10 suppresses an unnecessary rise in the temperature of the circulating water and reduces power consumption.

[0165] Although the first pump 45 and the heater 13 are turned on when it switches from the cooling operation to the hot water supply operation during the cooling / hot-water-supply switching operation in operation Mode A in the present embodiment, the first pump 45 and the heater 13 may similarly be turned on when it transitions from operation Mode D dedicated to the cooling operation to operation Mode C dedicated to the hot water supply operation, not limited to a running period of operation Mode A. However, in the actual operation of the air-conditioning hot-water-supply system 1, the possibility of transitioning from operation Mode D to operation Mode C is extremely low.

[0166] The heater 13 is provided primarily as a backup for assisting the heat pump in heating in order to: raise the temperature of the stored hot water in the hot water tank 12 to the hot-water-supply set temperature; and prevent the time required for the stored hot water temperature to reach the set temperature from becoming excessively long, even under a state where the heat output of the heat pump decreases due to a drop in the outside air temperature To during the hot water supply operation. Accordingly, it is configured such that the heater 13 is turned on when the outside air temperature To is equal to or below the predetermined outside air temperature set value Tos during the hot water supply operation (Step S34 to Step S36 in Fig. 7 and Step S58 to Step S60 in Fig. 8). This configuration avoids the so-called "hot water shortage", in which the stored hot water temperature in the hot water tank 12 falls and low-temperature water is delivered from faucets or showers.

[0167] Accordingly, the air-conditioning hot-water-supply system 1 of the present embodiment appropriately utilizes the heater 13 provided to assist the heating capacity of the heat pump when the outside air temperature To is equal to or below the predetermined outside air temperature set value Tos, and thereby achieves both of the following new effects: preventing a decrease in the stored hot water temperature in the hot water tank 12 during the transition from the cooling operation to the hot water supply operation; and shortening the time required for the stored hot water temperature to reach the hot-water-supply set temperature.

[0168] As another aspect of the air-conditioning hot-water-supply system 1, the outdoor unit 2 may include all the components that belong to the heat exchange unit 3 and are located on the side of the water heat exchanger 11 closer than the wavy lines P1 and P2 in Fig. 1. In this case, the outdoor unit 2 and the hot water tank 12 are connected only by piping through which the circulating water flows, and no piping for the refrigerant is connected. In this case, the piping through which the circulating water flows is exposed outdoors, and thus, there is a possibility that the circulating water in the piping may freeze while the air-conditioning hot-water-supply system 1 is stopped. Hence, when the outside air temperature To is low, the heater 13 and the first pump 45 provided in the outdoor unit 2 are operated, thereby preventing the circulating water in the outdoor piping from freezing under low outdoor temperature conditions.

[0169] As a further aspect of the air-conditioning hot-water-supply system 1, only the water heat exchanger 11 may be relocated from the heat exchange unit 3 to the outdoor unit 2. That is, the heat exchange unit 3 may be configured as an indoor unit including the expansion tank 49, the first pump 45, and the heater 13, which are located between the wavy lines P3 and P4 in Fig. 1, other than the water heat exchanger 11. In this case, the outdoor unit 2 and the indoor unit are connected by piping through which the circulating water flows, and thus, attention should be paid to the need for measures to prevent freezing of the circulating water in the piping, as in the above-described aspect. The hot water tank 12 may be disconnected from the heat exchange unit 3 at the portions of the wavy lines P5 and P6 in Fig. 1 so that the heat exchange unit 3 and the hot water tank 12 may be separated from each other, thereby allowing an increased degree of freedom in selecting installation locations for the heat exchange unit 3 and the hot water tank 12.

[0170] It may be configured such that: the position of the three-way valve 89 serving as a flow-path switching device for the circulating water is moved to the branching point Z; and the original position of the three-way valve 89 is changed to the branching (merging) point. That is, the positions of the branching point Z and the three-way valve 89 may be interchanged. In this case, the common path 41a is constituted by: the forward pipe 81 extending from the water heat exchanger 11 to the three-way valve 89; and the return pipe 83 extending from the branching point Z, which also serves as a merging point, to the water heat exchanger 11.

[0171] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.REFERENCE SIGNS LIST

[0172] 1air-conditioning hot-water-supply system 2outdoor unit 3heat exchange unit 5external apparatus 10controller 11water heat exchanger (heating-medium heat exchanger) 12hot water tank 13heater 14refrigerant piping 21refrigeration circuit 23compressor 25air heat exchanger 26outside-air temperature sensor (temperature sensor) 29four-way valve 41heating-medium circulation circuit 41acommon path 41bfirst heating-medium circulation circuit 41csecond heating-medium circulation circuit 45first pump 51outlet temperature sensor 52inlet temperature sensor 69hot-water-tank temperature sensor 89three-way valve (flow-path switching device)

Examples

Embodiment Construction

[0021]An air-conditioning hot-water-supply system according to the present embodiment will be described by referring to Figs. 1 to 8.

[0022]As shown in Fig. 1, the air-conditioning hot-water-supply system 1 includes: an outdoor unit 2 serving as a heat pump unit configured to exchange heat between the surrounding (outdoor) air and a refrigerant; a heat exchange unit 3 (i.e., hydro unit) accommodating a heating-medium heat exchanger 11 that exchanges heat between the refrigerant and a utilization-side heating medium; a plurality of external apparatuses 5 connected to the heat exchange unit 3; a remote controller 9 serving as an input device for receiving user operations; and a controller 10 configured to control respective components of the outdoor unit 2 and the heat exchange unit 3 on the basis of operations inputted to the remote controller 9. The external apparatuses 5 include at least one of a radiator 6 of a floor heating / cooling system and a fan coil unit 7 serving as an indoor...

Claims

1. An air-conditioning hot-water-supply system comprising: a refrigeration circuit that includes a heating-medium heat exchanger configured to exchange heat between a refrigerant and a heating medium and can perform heating and cooling of the heating medium by the refrigerant in the heating-medium heat exchanger; a common path that is connected to a utilization side of the heating-medium heat exchanger, allows a cooled heating medium to flow through the common path during a cooling operation using the heating medium cooled by the refrigeration circuit, and allows a heated heating medium to flow through the common path during a hot water supply operation using the heating medium heated by the refrigeration circuit; a heater that heats the heating medium; and a controller that controls the refrigeration circuit and the heater, wherein the controller turns on the heater for a predetermined period of time at a time of switching from the cooling operation to the hot water supply operation.

2. The air-conditioning hot-water-supply system according to claim 1, further comprising: a first heating-medium circulation circuit to which the common path is connected, and through which the cooled heating medium flows during the cooling operation; a second heating-medium circulation circuit to which the common path is connected, and through which the heated heating medium flows during the hot water supply operation; a flow-path switching device that is connected to the common path, the first heating-medium circulation circuit, and the second heating-medium circulation circuit and switches a flow of the heating medium from the common path to either the first heating-medium circulation circuit or the second heating-medium circulation circuit; and a pump that circulates the heating medium, wherein: the heater is provided in the common path or in the second heating-medium circulation circuit; and the controller is configured to further control the flow-path switching device and the pump.

3. The air-conditioning hot-water-supply system according to claim 2, further comprising: a hot water tank that is connected to the second heating-medium circulation circuit and exchanges heat between the heated heating medium and stored water; and a hot-water-tank temperature sensor that is provided in the hot water tank and detects the stored hot water temperature in the hot water tank.

4. The air-conditioning hot-water-supply system according to claim 3, further comprising an inlet temperature sensor that is provided at an inlet of the heating medium of the heating-medium heat exchanger, wherein the predetermined period of time is set to be a period of time until a temperature of the heating medium detected by the inlet temperature sensor reaches or exceeds the stored hot water temperature detected by the hot-water-tank temperature sensor.

5. The air-conditioning hot-water-supply system according to any one of claim 2 to claim 4, wherein the heater and the pump are provided in the common path.

6. The air-conditioning hot-water-supply system according to any one of claim 2 to claim 5, wherein: the refrigeration circuit includes a compressor configured to compress the refrigerant; and the controller is configured to temporarily turn off the pump at a time of switching from the cooling operation to the hot water supply operation, and turn on the heater after turning on the pump again and before turning on the compressor.

7. The air-conditioning hot-water-supply system according to any one of claim 1 to claim 6, wherein: the refrigeration circuit comprises an air heat exchanger configured to exchange heat between the refrigerant and ambient air and a temperature sensor configured to detect an ambient temperature at a location where the air heat exchanger is installed; and the controller is configured to turn on the heater when the ambient temperature detected by the temperature sensor is equal to or below a predetermined temperature during the hot water supply operation.

8. The air-conditioning hot-water-supply system according to any one of claim 1 to claim 7, wherein the controller is configured to perform switching between the cooling operation and the hot water supply operation alternately at predetermined time intervals, when simultaneous requests for the cooling operation and the hot water supply operation occur.

9. The air-conditioning hot-water-supply system according to any one of claim 2 to claim 6, further comprising a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, and the heater.

10. The air-conditioning hot-water-supply system according to claim 3 or claim 4, further comprising a heat exchange unit that accommodates the heating-medium heat exchanger, the common path, a part of the first heating-medium circulation circuit, the second heating-medium circulation circuit, the flow-path switching device, the pump, the heater, and the hot water tank.

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