Air conditioning and hot water supply system

Abstract

An air conditioning and hot water supply system (1) comprises: a refrigeration circuit (21) which includes a heat medium heat exchanger (11) for exchanging heat between a refrigerant and a heat medium, and which is capable of heating and cooling the heat medium by means of the refrigerant in the heat medium heat exchanger (11); a common path (41a) which is connected to a utilization side of the heat medium heat exchanger (11), and through which the heat medium cooled during space cooling operation flows and the heat medium heated during hot water supply operation flows; a heater (13) for heating the heat medium; and a control unit (10) for controlling the refrigeration circuit (21) and the heater (13). Upon switching from the space cooling operation to the hot water supply operation, the control unit (10) turns the heater (13) on for a predetermined time.

Description

Air conditioning and hot water supply system

[0001] An embodiment of the present invention relates to an air conditioning and hot water supply system.

[0002] Heat source systems are known that can provide hot water, cooling and heating, and heat and cold storage using a single heat source. For example, such heat source systems use a single heat pump as a heat source to provide heating and cooling, heat and cold storage, hot water storage, hot water supply, and bath reheating. Furthermore, these heat source systems control these functions using a single control system.

[0003] Japanese Patent Application Publication No. 7-253228

[0004] In an air conditioning and hot water supply system equipped with a heat pump refrigeration cycle, which performs air conditioning and hot water supply using a heat medium such as water, the hot water stored in the hot water supply tank is heated by the heat medium heated by the heat pump. During heating and cooling operation, the heat medium cooled or heated by the heat pump is supplied to air conditioning equipment such as a fan coil unit installed in the room.

[0005] In such air conditioning and hot water supply systems, cooling and hot water supply operations can sometimes be set simultaneously in the summer. In this case, because only one heat medium is used, cooling and hot water supply operations cannot be performed simultaneously. Therefore, by alternating between cooling and hot water supply operations by using a heat pump to cool and heat the heat medium at predetermined intervals and switching a valve that changes the flow path of the heat medium in conjunction with this, cooling of the room and heating of the hot water stored in the hot water tank can both be achieved.

[0006] However, when switching from cooling operation to hot water supply operation, cooled heat transfer medium (circulating water) remains in the common path between the cooling and hot water supply paths. Furthermore, during cooling operation, metal piping, such as copper, located in the common path is also cooled and remains at a low temperature. Therefore, when switching from cooling operation to hot water supply operation, the cooled heat transfer medium flows into the hot water tank, lowering the temperature of the hot water stored in the tank. Furthermore, because the cooling and hot water supply operations are switched between at regular intervals, the time available for heating the hot water tank by the hot water supply operation is limited. Therefore, each time the system switches from cooling operation to hot water supply operation, the temperature of the hot water stored in the hot water tank drops, lengthening the time it takes for the hot water temperature to reach the hot water supply setting temperature.

[0007] Therefore, the present invention aims to provide an air conditioning and hot water supply system that can suppress a decrease in the temperature of stored hot water in the hot water tank when switching from air conditioning operation to hot water supply operation, and shorten the time it takes for the stored hot water temperature to reach the hot water supply set temperature.

[0008] In order to solve the above problem, an air conditioning and hot water supply system according to an embodiment of the present invention includes: a refrigeration circuit having a heat medium heat exchanger that exchanges heat between a refrigerant and a heat medium, and capable of heating and cooling the heat medium with the refrigerant in the heat medium heat exchanger; a common path connected to the user side of the heat medium heat exchanger, through which the cooled heat medium flows during air conditioning operation using the heat medium cooled in the refrigeration circuit, and through which the heated heat medium flows during hot water supply operation using the heat medium heated in the refrigeration circuit; a heater that heats the heat medium; and a control unit that controls the refrigeration circuit and the heater, wherein the control unit turns on the heater for a predetermined period of time when switching from the air conditioning operation to the hot water supply operation.

[0009] An air conditioning and hot water supply system according to an embodiment of the present invention includes: a first heat medium circulation circuit connected to the common path and through which cooled heat medium flows during cooling operation; a second heat medium circulation circuit connected to the common path and through which heated heat medium flows during hot water supply operation; a flow path switching device connected to the common path, the first heat medium circulation circuit, and the second heat medium circulation circuit and switching the flow of the heat medium from the common path to either the first heat medium circulation circuit or the second heat medium circulation circuit; and a pump that circulates the heat medium, wherein it is preferable that the heater is provided in the common path or the second heat medium circulation circuit, and the control unit further controls the flow path switching device and the pump.

[0010] It is preferable that the air conditioning and hot water supply system according to an embodiment of the present invention further comprises a hot water tank connected to the second heat medium circulation circuit for heat exchange between the heated heat medium and stored hot water, and a hot water tank temperature sensor provided in the hot water tank for detecting the temperature of the hot water stored in the hot water tank.

[0011] An air conditioning and hot water supply system according to an embodiment of the present invention preferably includes an inlet temperature sensor provided at the inlet of the heat medium of the heat medium heat exchanger, and the predetermined time is preferably the time required for the temperature of the heat medium detected by the inlet temperature sensor to become equal to or higher than the stored hot water temperature detected by the hot water tank temperature sensor.

[0012] In the air conditioning and hot water supply system according to the embodiment of the present invention, the heater and the pump are preferably provided in the common path.

[0013] The refrigeration circuit of the air conditioning and hot water supply system according to an embodiment of the present invention preferably includes a compressor that compresses the refrigerant, and when switching from the air conditioning operation to the hot water supply operation, the control unit preferably turns the pump OFF once and then ON again, and then turns the heater ON before turning the compressor ON.

[0014] The refrigeration circuit of the air conditioning and hot water supply system according to an embodiment of the present invention comprises an air heat exchanger that exchanges heat between the refrigerant and the surrounding air, and a temperature sensor that detects the ambient temperature of the location where the air heat exchanger is installed, and it is preferable that the control unit turns on the heater when the ambient temperature detected by the temperature sensor is below a predetermined temperature during the hot water supply operation.

[0015] In the air conditioning and hot water supply system according to an embodiment of the present invention, when simultaneous requests for the cooling operation and the hot water supply operation are made, it is preferable that the control unit alternates between the cooling operation and the hot water supply operation at predetermined time intervals.

[0016] The air conditioning and hot water supply system according to the embodiment of the present invention preferably includes a heat exchange unit that houses the heat medium heat exchanger, the common path, a part of the first heat medium circulation circuit, the second heat medium circulation circuit, the flow path switching device, the pump, and the heater.

[0017] It is preferable that the air conditioning and hot water supply system according to the embodiment of the present invention includes a heat exchange unit that houses the heat medium heat exchanger, the common path, a part of the first heat medium circulation circuit, the second heat medium circulation circuit, the flow path switching device, the pump, the heater, and the hot water tank.

[0018] According to the present invention, an air conditioning and hot water supply system can be provided that can suppress a decrease in the temperature of hot water stored in the hot water tank when switching from air conditioning operation to hot water supply operation, thereby shortening the time it takes for the stored hot water temperature to reach the hot water supply set temperature.

[0019] FIG. 1 is a system configuration diagram of an air conditioning hot water supply system according to an embodiment of the present invention. FIG. 2 is a conceptual diagram showing an example of time-series changes in the stored hot water temperature, the water heat exchanger inlet temperature, and the operation of the heater during cooling / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention. FIG. 3 is a timing chart showing the operation of each component during cooling / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention, and a diagram showing the corresponding changes in the water heat exchanger inlet temperature and stored hot water temperature over time. FIG. 4 is a diagram showing an example of changes in the stored hot water temperature and the water heat exchanger inlet temperature over time during cooling / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention. FIG. 5 is a timing chart showing the operation of each component during heating / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention. FIG. 6 is a diagram showing a control flow for each operation mode of the air conditioning hot water supply system according to an embodiment of the present invention. FIG. 7 is a diagram showing a control flow for cooling / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention. FIG. 8 is a diagram showing a control flow for heating / hot water supply switching operation of the air conditioning hot water supply system according to an embodiment of the present invention.

[0020] The air conditioning and hot water supply system according to this embodiment will be described with reference to FIGS. 1 to 8. FIG.

[0021] As shown in FIG. 1 , the air conditioning and hot water supply system 1 includes an outdoor unit 2 (Outdoor Unit) as a heat pump unit that exchanges heat between the surrounding (outdoor) air and a refrigerant, a heat exchange unit 3 (Hydro Unit) that houses a heat medium heat exchanger 11 that exchanges heat between the refrigerant and a user-side heat medium (heating medium), multiple outdoor devices 5 connected to the heat exchange unit 3, a remote controller 9 as an input device that accepts operations by a user, and a control unit 10 that controls each device of the outdoor unit 2 and the heat exchange unit 3 based on operations input to the remote controller 9. The outdoor devices 5 include, for example, at least one of a radiator 6 of a floor heating and cooling system and a fan coil unit 7 as an indoor unit of an air conditioning system. Note that the number of outdoor devices 5 may be one or more.

[0022] In this embodiment, water is used as the use-side heat medium, but the use-side heat medium is not limited to water and may be other fluids such as antifreeze. Hereinafter, the use-side heat medium will be simply referred to as heat medium, circulating water, or water, and the heat medium heat exchanger 11 will be referred to as water heat exchanger 11. The refrigerant may be R410A, R32, CO ２ A variety of refrigerants are available.

[0023] The air conditioning and hot water supply system 1 includes a refrigeration circuit 21 that circulates a refrigerant between 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 refrigerant flow direction, an air heat exchanger 25 that functions as an evaporator and condenser and exchanges heat between the refrigerant and the surrounding air, an expansion valve 27, a water heat exchanger 11 that functions as a condenser and evaporator and exchanges heat between the refrigerant and circulating water, and a refrigerant pipe 14 that connects these devices and circulates the refrigerant. The water heat exchanger 11 is a plate-type heat exchanger or a double-pipe heat exchanger. The refrigeration circuit 21 is sometimes referred to as a heat pump.

[0024] The outdoor unit 2 houses the compressor 23, four-way valve 29, air heat exchanger 25, expansion valve 27, and part of the refrigerant pipe 14 of the refrigeration circuit 21. Meanwhile, the heat exchange unit 3 houses part of the refrigerant pipe 14, the heater 13, the hot water tank 12, the piping that serves as the circulating water flow path, a first pump 45 and a second pump 91 (described below) that circulate the circulating water, a flow path switching device 89 that switches the flow path of the circulating water, various sensors, and a control unit 10. The water stored in the hot water tank 12, which has a volume of approximately 100 to 300 liters, is typically tap water supplied from outside the unit through a water pipe and heated by the circulating water. The water heated in the hot water tank 12, i.e., the stored hot water, is supplied to hot water destinations such as the washroom, kitchen, and bathroom. The control unit 10 is not limited to being housed in the heat exchange unit 3, but may also be housed in the outdoor unit 2 or the remote controller 9. Furthermore, a plurality of control units 10 may be distributed among the heat exchange unit 3, the outdoor unit 2 and / or the remote controller 9, and the respective control units 10 may operate in cooperation with each other.

[0025] Generally, 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 by connecting pipes 15 and 16 of the refrigerant pipe 14 and a communication line (not shown). In other words, only the refrigerant flows between the outdoor unit 2 and the heat exchange unit 3, and the air conditioning and hot water supply system 1 does not require outdoor piping for circulating water. Therefore, the air conditioning and hot water supply system 1 can avoid freezing of circulating water in the outdoor piping when the outside temperature is low.

[0026] During cooling operation, the air conditioning and hot water supply system 1 cools the circulating water using the refrigeration circuit 21 and circulates the circulating water at, for example, 7° C. to 25° C. to the external device 5.

[0027] Furthermore, during heating operation and hot water supply operation, the air conditioning and hot water supply system 1 heats the circulating water with the heat pump to obtain circulating water at a first temperature, for example, 20°C to 65°C.

[0028] The air conditioning and hot water supply system 1 circulates circulating water at a first temperature to an external device 5 without passing through a hot water tank 12 during heating operation, and circulates circulating water at a first temperature to the hot water tank 12 without passing through the external device 5 during hot water supply operation.

[0029] Furthermore, during hot water supply operation, the air conditioning and hot water supply system 1 can circulate circulating water at a second temperature higher than the first temperature, for example, approximately 65°C, to the hot water supply tank 12 by combining heating of the circulating water by the heat pump with heating of the circulating water by the heater 13 provided downstream of the water heat exchanger 11 in the heat exchange unit 3. This allows the air conditioning and hot water supply system 1 to store hot water at approximately 65°C in the hot water supply tank 12. When the ambient temperature where the outdoor unit 2 is installed, 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, so the heater 13 is turned on to promote heating of the circulating water.

[0030] Furthermore, during hot water supply operation, the air conditioning and hot water supply system 1 heats, or boils, the supply water stored in the hot water supply tank 12 by using the circulating water circulating in the heat exchange unit 3 .

[0031] The air conditioning and hot water supply system 1 configured as described above has the following basic functions: (1) A function for circulating a refrigerant between the outdoor unit 2 and the heat exchange unit 3 and exchanging heat between the refrigerant and circulating water in the water heat exchanger 11 in the heat exchange unit 3. (2) A function for circulating either cooled circulating water or heated circulating water between the heat exchange unit 3 and the multiple outdoor devices 5 to air-condition the room in which the outdoor devices 5 are installed. (3) A function for circulating heated circulating water in the hot water supply tank 12 to heat the water supply in the hot water supply tank 12 to produce stored hot water (hot water), and supply the water to a hot water supply destination as needed.

[0032] The outdoor unit 2 is equipped with an outdoor air temperature sensor 26. This outdoor air temperature sensor 26 detects the temperature of the air on the windward side before passing through the air heat exchanger 25 as the outdoor air temperature To, which is the ambient temperature of the air heat exchanger 25, and outputs it to the control unit 10.

[0033] The compressor 23 compresses the refrigerant, increases its pressure, and discharges it. The compressor 23 preferably has an operating frequency that can be changed by known inverter control via an inverter device (not shown). Increasing the rotation speed of the compressor 23 increases the amount of heat transferred to high-temperature areas, while decreasing the rotation speed of the compressor 23 decreases the amount of heat transferred to high-temperature areas. In this case, the control unit 10 detects the air conditioning load or hot water supply load and increases or decreases the operating frequency of the inverter device accordingly, thereby achieving an appropriate refrigeration capacity according to the load state.

[0034] The expansion valve 27 is, for example, an electronic expansion valve (Pulse Motor Valve, PMV) whose valve opening degree can be electrically adjusted.

[0035] The four-way valve 29 switches the flow direction of the refrigerant circulating through the compressor 23, the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11. When heating the circulating water in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 through the water heat exchanger 11, the expansion valve 27, and the air heat exchanger 25 in this order, as indicated by the solid arrows in FIG. 1 . In this case, the water heat exchanger 11 functions as a condenser. The refrigerant that has passed through the water heat exchanger 11 returns to the outdoor unit 2 via the crossover pipe 16, passes through the expansion valve 27, and is reduced in pressure, becoming a low-pressure two-phase gas-liquid refrigerant. It is then sent to the air heat exchanger 25. A blower (not shown) blows outside air through the air heat exchanger 25. The low-pressure two-phase gas-liquid refrigerant is heated by the outside air passing through the air heat exchanger 25, becoming a gas-phase refrigerant. In this case, the air heat exchanger 25 functions as an evaporator. The refrigerant that has passed through the air heat exchanger 25 and turned into a gas phase returns to the compressor 23. The evaporator is also called a heat absorber, and the condenser is also called a heat radiator.

[0036] On the other hand, when cooling circulating water in the refrigeration circuit 21, the four-way valve 29 directs the refrigerant discharged from the compressor 23 through the air heat exchanger 25, the expansion valve 27, and the water heat exchanger 11 in this order, as shown by the dashed arrows in FIG. 1 . Here, the high-temperature, 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, high-pressure refrigerant is cooled by outside air passing through the air heat exchanger 25 and becomes a high-pressure liquid-phase refrigerant. At this time, the air heat exchanger 25 functions as a condenser. The refrigerant that has passed through the air heat exchanger 25 is reduced in pressure by passing through the expansion valve 27 and becomes a low-pressure gas-liquid two-phase refrigerant. The refrigerant is then sent to the heat exchange unit 3 via the crossover pipe 16 and enters the water heat exchanger 11. The water heat exchanger 11 cools the circulating water passing through the water heat exchanger 11 with 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. At this time, the water heat exchanger 11 functions as an evaporator. The refrigerant that has passed through the water heat exchanger 11 and become a gas-phase refrigerant returns to the outdoor unit 2 via the connecting pipe 15 and is sucked into the compressor 23.

[0037] The heat exchange unit 3 includes a part of a heat medium circulation circuit 41, which is a water circuit that circulates circulating water that has undergone heat exchange in the water heat exchanger 11 between the water heat exchanger 11 and a plurality of external devices 5 during cooling and heating operations, and circulates circulating water that has been heated in the water heat exchanger 11 between the water heat exchanger 11 and the hot water tank 12 during hot water operation. The flow direction of the circulating water is selectively switched by a flow path switching device 89 to either the external device 5 side or the hot water tank 12 side.

[0038] The heat medium circulation circuit 41 is provided with an outlet temperature sensor 51 at the circulating water outlet of the water heat exchanger 11, an inlet temperature sensor 52 at the circulating water inlet of the water heat exchanger 11, and a flow rate sensor 53 for measuring the flow rate of the circulating water. The outputs of these outlet temperature sensor 51, inlet temperature sensor 52, and flow rate sensor 53 are supplied to the control unit 10, along with the outputs of the other sensors. The circulating water circulates unidirectionally through the heat medium circulation circuit 41 by operation of the first pump 45. The heat 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 made of metal pipes such as copper or iron.

[0039] The outlet temperature sensor 51 detects the temperature of the circulating water immediately after heat exchange in the water heat exchanger 11 and outputs the result to the control unit 10. The inlet temperature sensor 52 detects the temperature of the circulating water immediately before heat exchange in the water heat exchanger 11 and outputs the result to the control unit 10. The temperature detected by the inlet temperature sensor 52 is the temperature of the circulating water that has exchanged heat with the indoor air in the multiple external devices 5 and returned during air conditioning operation for heating and cooling, and is the temperature of the circulating water that has exchanged heat with supply water in the hot water tank 12 and returned during hot water supply operation. Hereinafter, the temperature of the circulating water detected by the inlet temperature sensor 52 will be referred to as the water heat exchanger inlet temperature.

[0040] During hot water supply operation, the circulating water heated by the water heat exchanger 11 is sucked into the driven first pump 45 and sent to the hot water supply tank 12 through the circulating water piping 43. The circulating water exchanges heat with the supply water in the hot water supply tank 12 to heat the supply water. The circulating water, whose temperature has been reduced by the heat exchange, is returned to the water heat exchanger 11, heated by the refrigerant circulating in the refrigeration circuit 21, and circulates again in the heat medium circulation circuit 41.

[0041] The hot water tank 12 comprises a stainless steel tank 61 capable of storing water supply, a water supply pipe 65 that supplies water supply such as city water into the tank 61 from an outlet 63 provided at the bottom of the tank, a coil 67 that circulates water within the tank 61 and indirectly heats the water supply in the tank 61, a hot water tank temperature sensor 69 that detects the temperature of the hot water stored in the tank 61, a hot water supply pipe 71 that leads the heated hot water stored in the tank 61 out of the tank 61, and insulation 73 that covers the outer surface of the tank 61.

[0042] Tank 61 is an airtight container except for water supply pipe 65 and hot water supply pipe 71. When stored hot water is supplied to the hot water supply destination connected to hot water supply pipe 71, water is supplied into tank 61 from outlet 63 of water supply pipe 65 to make up for the amount of hot water supplied. Therefore, tank 61 is always kept full of water. Hot water supply pipe 71, which supplies hot water stored in tank 61, is installed in upper mirror plate 75, which forms the ceiling of tank 61. Generally, hot water supply tank 12 uses the water pressure of tap water acting on a water pipe connected to water supply pipe 65 to push out stored hot water in tank 61 and supply hot water to the destination connected to hot water supply pipe 71.

[0043] Coil 67 has a circulating water inlet pipe 67a that penetrates upper head plate 75 in the vertical direction and extends linearly downward within tank 61, a spiral portion 67b that follows circulating water inlet pipe 67a and spirals, and a circulating water return pipe 67c that extends linearly upward within tank 61 from the end of spiral portion 67b and penetrates upper head plate 75 in the vertical direction. Coil 67 located within tank 61 is filled with feed water, and heat exchange occurs between the high-temperature circulating water circulating inside coil 67 and the feed water or stored hot water stored in hot water tank 12, thereby heating the feed water or stored hot water.

[0044] The hot water supply tank temperature sensor 69 detects a representative value of the temperature of the hot water stored in the tank 61. The output of the hot water supply tank temperature sensor 69 is input to the control unit 10. The hot water supply tank temperature sensor 69 is provided inside a thin, cylindrical temperature sensor holder 77 that protrudes downward from the upper head plate 75. The temperature sensor holder 77 extends downward from a location suitable for detecting the temperature of the hot water stored in the tank 61, for example, from the upper head plate 75 toward the center 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 supply tank temperature sensor 69 detects the temperature of the hot water transmitted from the outer surface of the temperature sensor holder 77 to its inner surface.

[0045] The insulating material 73 is provided around the tank 61 to prevent direct heat radiation into the atmosphere and prevent a drop in the temperature of the hot water stored in the tank 61. The insulating material 73 is made of polystyrene foam or a urethane foam material, which has better insulating properties than polystyrene foam. Vacuum insulating material, which has even better insulating properties, may also be used. The lower part of the tank 61 does not have any insulating material because tap water, which is the water supply before heating, is supplied from the outlet 63 of the water supply pipe 65 provided at the lower part, and there is little need to keep it warm.

[0046] Focusing on the circulation path of the circulating water, the heat medium circulation circuit 41 includes, in addition to the circulating water piping 43, an external circulating water piping 87 that is located farther from the water heat exchanger 11 than the circulating water piping 43 and that circulates the circulating water to the external device 5, a branch point Z that branches the circulating water that has flowed through the circulating water piping 43 into the external circulating water piping 87, and a flow path switching device 89 that switches the circulation path of the circulating water to either the hot water tank 12 side or the external device 5 side.

[0047] The circulating water piping 43 consists of an outward pipe 81 that leads the circulating water heated in the water heat exchanger 11 to the coil 67 of the hot water tank 12 or to the external device 5, and a return pipe 83 that leads the circulating water whose temperature has been reduced by heating the supply water in the tank 61 or the circulating water that has been heat exchanged in the external device 5 to the water heat exchanger 11.

[0048] The outward pipe 81 is provided with, in this order, a first pump 45 that circulates the circulating water, a heater 13 that heats the circulating water passing through it, and an expansion tank 49 that absorbs the expansion (increase in volume) of the heated circulating water. The expansion tank 49 is connected independently to a pipe branching off from the outward pipe 81. A flow rate sensor 53 is provided midway along the return pipe 83.

[0049] The external circulating water piping 87 includes an external outward pipe 95 that leads the circulating water toward the external device 5, which is one of the branches at branch point Z that branches in two directions at the end of the outward pipe 81, and an external return pipe 97 that returns the circulating water used in the external device 5 to the return pipe 83. The other end of branch point Z is connected to a circulating water inlet pipe 67a that introduces circulating water into the hot water supply tank 12.

[0050] The external outward pipe 95 branches into two directions: a first outward pipe 95a that sends circulating water to the radiator 6, and a second outward pipe 95b that sends circulating water to the indoor unit 7. Meanwhile, the external return pipe 97 is where a first return pipe 97a that returns circulating water from the radiator 6 and a second return pipe 97b that returns circulating water from the indoor unit 7 converge.

[0051] A mixing valve 93 and a second pump 91 are sequentially connected to the second outward pipe 95b. One end of the mixing valve 93 is connected to the middle of the second return pipe 97b, and by changing the opening of this mixing valve 93, the amount of circulating water used by the indoor unit 7 mixed with the circulating water heading toward the indoor unit 7 is changed, thereby controlling the temperature of the circulating water circulating through the indoor unit 7 to satisfy the temperature requirement set for the indoor unit 7. The second pump 91 operates only when the indoor unit 7 requests cooling or heating operation and is capable of such operation, and is stopped in other operating states (such as hot water supply operation). The circulating water after use in the external device 5 is returned to the return pipe 83 of the heat medium circulation circuit 41 between the hot water supply tank 12 and the water heat exchanger 11 via the external return pipe 97 of the external circulating water piping 87.

[0052] In this embodiment, the air conditioning and hot water supply system 1 is capable of supplying cooled or heated circulating water to two external devices 5 (a radiator 6 and an indoor unit 7), but the number of external devices 5 may be one.

[0053] At branch point Z, the circulating water from the outflow pipe 81 flows to the external outflow pipe 95 during cooling and heating operation, and flows to the other branch path, the circulating water inlet pipe 67a, during hot water supply operation.

[0054] Although various configurations of the flow path switching device 89 are conceivable, such as a combination of multiple valves, in this embodiment, an example using a three-way valve 89, which has the simplest piping configuration, will be described. The three-way valve 89 has a constantly open outlet and two inlets, one of which can be switched to connect to the outlet. The outlet of the three-way valve 89 is connected to the return pipe 83, one inlet is connected to the external return pipe 97, and the other inlet is connected to the circulating water return pipe 67c extending from the hot water tank 12. Therefore, by switching the connection direction of the three-way valve 89 between cooling operation, heating operation, and hot water operation, the circulating water path can be switched between the hot water tank 12 side and the external device 5 side.

[0055] As described above, the heat medium circulation circuit 41 includes a circulation path for circulating water through the external device 5 and a circulation path for circulating water through the hot water supply tank 12. These circulation paths share a portion in common. The common path 41a as this common portion includes two pipes: an outward pipe 81 connected to the outlet piping on the user side of the water heat exchanger 11 and extending from the water heat exchanger 11 to the branch point Z; and a return pipe 83 connected to the inlet piping on the user side of the water heat exchanger 11 and extending from the three-way valve 89 to the water heat exchanger 11. Hereinafter, the portion of the circulation path for circulating water through the external device 5 excluding the common path 41a will be referred to as a first heat medium circulation circuit 41b, and the portion of the circulation path for circulating water through the hot water supply tank 12 excluding the common path 41a will be referred to as a second heat medium circulation circuit 41c. Therefore, the outlet of the three-way valve 89 is connected to the common path 41a, one inlet of the three-way valve 89 is connected to the first heat medium circulation circuit 41b, and the other inlet of the three-way valve 89 is connected to the second heat medium circulation circuit 41c. The first heat medium circulation circuit 41b is essentially the path of the external circulating water piping 87. The second heat medium circulation circuit 41c is specifically a path that starts from the branch point Z, passes through the circulating water inlet piping 67a, the spiral portion 67b in the hot water tank 12, and the circulating water return piping 67c, and reaches the three-way valve 89.

[0056] The air conditioning and hot water supply system 1 can perform both cooling operation of the external device 5 and hot water supply operation of the hot water tank 12, or can perform both heating operation of the external device 5 and hot water supply operation, by switching the circulation path of the circulating water between the first heat medium circulation circuit 41b and the second heat medium circulation circuit 41c in a time-division manner at predetermined time intervals using the three-way valve 89 in response to instructions from the control unit 10.

[0057] The common path 41a includes a first pump 45, a heater 13, and an expansion tank 49, which are provided in the outgoing pipe 81. The heater 13 may be moved to the second heat medium circulation circuit 41c, but in this case, the heater 13 cannot be used as an auxiliary heat source during heating operation of the external device 5.

[0058] There is at least one remote controller 9. The remote controller 9 may include, for example, a remote controller provided in the outdoor unit 2, a remote controller provided in the heat exchange unit 3, and a remote controller (not shown) installed on a wall surface inside the room.

[0059] The remote controller 9 includes a setting unit (not shown) as an input interface for setting the set temperature of the circulating water and the operating mode of the air conditioning and hot water supply system 1, and a display unit (not shown) that displays the set contents and operating status as operating conditions of the outdoor unit 2, the heat exchange unit 3, and the outdoor device 5. The remote controller 9 transmits the set temperature of the circulating water to be circulated to the outdoor device 5, the set temperature for boiling hot water in the hot water tank 12 (hot water set temperature), and the operating mode of the air conditioning and hot water supply system 1, which are set by the user via the setting unit, to the control unit 10 as control signals.

[0060] The control unit 10 includes a microprocessor (not shown) and a storage device (not shown) that stores various calculation programs executed by the microprocessor, parameters, etc. The control unit 10 loads the various control programs from the auxiliary storage device to the main storage device, and executes the various control programs loaded into the main storage device using the central processing unit within the microprocessor. The control unit 10 executes sequence control based on detection values ​​from various sensors, such as the outlet temperature sensor 51, inlet temperature sensor 52, and flow rate sensor 53, and instructions from the remote controller 9. The control unit 10 may be configured with a logic circuit to execute this sequence control.

[0061] Based on control signals received from the remote controller 9 via a wired or wireless communication line and outputs from various sensors, the control unit 10 controls the operation of the air conditioning and hot water supply system 1, including the control of the compressor 23 and four-way valve 29 of the refrigeration circuit 21, and the control of the first pump 45, three-way valve 89, and heater 13 in the heat exchange unit 3. For example, the control unit 10 controls the operation of the air conditioning and hot water supply system 1 so that the temperature detected by the hot water tank temperature sensor 69 in the tank 61 becomes the hot water setting temperature of the hot water tank 12.

[0062] Furthermore, the control unit 10 switches the path of the circulating water from the common path 41a to either the first heat medium circulation circuit 41b on the external device 5 side or the second heat medium circulation circuit 41c on the hot water tank 12 side by controlling the switching of the three-way valve 89. Furthermore, the control unit 10 alternately switches the circulating water path between the external device 5 side and the hot water tank 12 side, thereby achieving both the heating of hot water stored in the hot water tank 12 and the supply of circulating water to the external device 5. The remote controller 9 allows the user to set the operating mode that switches between these operating states via the operation unit.

[0063]

[0064] As shown in Table 1, the air conditioning and hot water supply system 1 can be set by the remote controller 9, and preferably has, for example, at least six modes including stop as operating modes controlled by the control unit 10, but does not necessarily have to have heating operation during air conditioning operation.

[0065] In Table 1, an air conditioning request means that the user has set the external device 5 (radiator 6 and / or indoor unit 7) to either cooling or heating. The term "cooling on" in an air conditioning request indicates a state in which the user has set cooling and the room temperature, etc., in which the external device 5 is installed has not reached the set temperature for cooling. The term "heating on" in an air conditioning request indicates a state in which the user has set heating and the room temperature, etc., in which the external device 5 is installed has not reached the set temperature for heating. The term "thermo off" in an air conditioning request indicates a state in which the user has set either cooling or heating and the room temperature, etc., in which the external device 5 is installed has reached the set temperature for cooling or heating, i.e., a state in which the air conditioning operation satisfies the air conditioning conditions. Furthermore, the term "completely stopped" indicates a state in which the user has not set either cooling or heating for the external device 5 and no air conditioning operation is required.

[0066] On the other hand, a "yes" temperature increase request during hot water supply indicates a state in which the user has set the hot water supply operation and the temperature of the hot water stored in the hot water tank 12 has not reached the hot water supply set temperature. In contrast, a "no" temperature increase request during hot water supply indicates a state in which the user has not set the hot water supply operation and hot water supply is not required, or a state in which the user has set the hot water supply operation but the temperature of the hot water stored in the hot water tank 12 has reached the hot water supply set temperature.

[0067] Depending on the combination of the above user settings and the operating states of the external device 5 and the hot water tank 12, the control unit 10 determines one of six modes, Mode A to Mode E and Stop.

[0068] Mode A is an operation mode when the external device 5 has an air conditioning request for cooling and a request for increasing the temperature in hot water supply operation. In Mode A, the control unit 10 alternates between cooling operation and hot water supply operation at predetermined time intervals. Mode A is also called cooling / hot water supply switching operation or cooling / hot water supply combined operation.

[0069] Mode B is an operation mode when the external device 5 requests heating for air conditioning and a temperature increase in hot water supply operation. In Mode B, the control unit 10 alternates between heating operation and hot water supply operation at predetermined time intervals. Mode B is also called heating and hot water supply switching operation or combined heating and hot water supply operation.

[0070] Mode C is an operation mode when the air conditioning request is thermo-off or completely stopped in the external device 5 and there is a temperature increase request 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.

[0071] Mode D is an operation mode when the air conditioning request is for cooling and there is no request for increasing the temperature in the hot water supply operation in the external device 5. In other words, mode D is an operation mode in which only cooling operation is performed.

[0072] Mode E is an operation mode when the air conditioning request is for heating and there is no request for increasing the temperature in the hot water supply operation in the external device 5. In other words, mode E is an operation mode in which only the heating operation is performed.

[0073] Next, the control of the heater 13 by the control unit 10 will be described in more detail.

[0074] In the cooling / hot water supply switching operation of operation mode A, cooling operation and hot water supply operation are switched at predetermined time intervals. At this time, cooled circulating water remains in the common path 41a of the heat medium circulation circuit 41 when switching from cooling operation to hot water supply operation. If the cooled circulating water were sent directly to the hot water supply tank 12 when switching from cooling operation to hot water supply operation, the cooled circulating water would significantly reduce the temperature of the stored hot water in the hot water supply tank 12. Furthermore, because the piping constituting the common path 41a of the heat medium circulation circuit 41 is made of metal, these piping are kept at a low temperature by the cooled circulating water, which further reduces the temperature of the circulating water. As a result, it takes a longer time for the stored hot water temperature to reach the hot water supply setting temperature.

[0075] Therefore, when switching from cooling operation to hot water supply operation, the control unit 10 turns on the heater 13 for a predetermined time, thereby heating the circulating water that passes through the outflow pipe 81 in which the heater 13 is installed and flows to the hot water supply tank 12. This prevents the stored hot water temperature from dropping excessively due to cooled circulating water remaining in the common path 41a when switching from cooling operation to hot water supply operation. Furthermore, it is possible to shorten the time it takes for the stored hot water temperature to reach the hot water supply setting temperature. Note that it is preferable that the predetermined time for turning on the heater 13 can be set by the user. In this case, the predetermined time for turning on the heater 13 may be set via the setting unit of the remote controller 9.

[0076] As shown in Fig. 2, in the air conditioning and hot water supply system 1 according to this embodiment, in which the heater 13 is turned on, when the system switches from cooling operation to hot water supply operation, the circulating water is heated by the heater 13 for a predetermined heater operation time set value Tmh2. Note that in Fig. 2, the term "cooling" refers to cooling operation, and the term "hot water supply" refers to hot water supply operation. The cooling operation time set value in mode A is Tm1s, and the hot water supply operation time set value in mode A is Tm2s.

[0077] When the heater 13 is turned on, the water heat exchanger inlet temperature begins to rise. After the heater 13 is turned off, the heat pump heats the circulating water, gradually increasing the temperature until the hot water supply operation is terminated. Therefore, even if cooled circulating water remaining in the common path 41a is sent to the hot water supply tank 12, the decrease in the stored hot water temperature when switching from cooling operation to hot water supply operation is suppressed compared to when the heater 13 is not turned on. This allows the air conditioning and hot water supply system 1 to shorten the time it takes for the stored hot water temperature to reach the hot water supply set temperature. In the example 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 operating mode. At this point, the hot water supply operation is no longer requested to increase the temperature, and the operation transitions from mode A to mode D, which performs only cooling operation.

[0078] Here, referring to FIG. 3 , the operation of each component controlled by the control unit 10 and the time changes in the stored hot water temperature and the water heat exchanger inlet temperature corresponding to the operation of each component when switching from cooling operation to hot water operation in operation mode A will be described. In the timing chart shown in the lower part of FIG. 3 , the notations for the operating states "hot water supply" and "cooling" are the same as those in FIG. 2 . Furthermore, the notation "heating" of the four-way valve refers to switching the refrigerant in the water heat exchanger 11 to a refrigerant circulation path that heats the circulating water, and the notation "cooling" refers to switching the refrigerant in the water heat exchanger 11 to a refrigerant circulation path that cools the circulating water. Furthermore, the notation "pump" refers to the first pump 45. Furthermore, the notation "hot water tank" of the three-way valve refers to the three-way valve 89 setting the circulating water circulation path to the hot water tank 12 side, and the notation "external device" refers to the three-way valve 89 setting the circulating water circulation path to the external device 5 side. These notations are also used in the other figures described below.

[0079] At time t0, when the operation mode switches from cooling operation to hot water supply operation, the compressor 23 is temporarily turned OFF. After that, at time t1, the three-way valve 89 has already switched its flow path from the external device 5 side to the hot water supply tank 12 side, the first pump 45 is turned ON, and even though the circulating water is not being 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 supply tank 12. That is, in the upper graph of Figure 3, the water heat exchanger inlet temperature begins to rise.

[0080] Next, at time t2, the heater 13 is turned on, the circulating water is further heated by the heater 13, and the rate of increase in the water heat exchanger inlet temperature in the upper graph of FIG. 3 increases.

[0081] Next, at time t3, the compressor 23 is turned ON, and at almost the same time, the four-way valve 29 switches from cooling to heating, the circulating water is heated by the refrigerant in the water heat exchanger 11, and the rate of increase in the water heat exchanger inlet temperature in the upper graph in Figure 3 further increases. In other words, from time t3 onwards, the circulating water is heated by three heat sources: the stored hot water, the heater 13, and the refrigerant.

[0082] As shown in the upper graph of Figure 3, under conditions where the water heat exchanger inlet temperature is lower than the stored hot water temperature, the stored hot water continues to lose heat to the circulating water, and the stored hot water temperature continues to decrease, albeit very slightly.

[0083] 4, the change in the rate of increase of the water heat exchanger inlet temperature when the water heat exchanger inlet temperature becomes higher than the stored hot water temperature during the hot water supply operation after the operation mode is switched from the cooling operation to the hot water supply operation. In the example of FIG. 4, the start of the time interval T corresponds to time t1 in FIG. 3.

[0084] As shown in Figure 4, during time interval T, the water heat exchanger inlet temperature is below the stored hot water temperature. Therefore, the stored hot water continues to give heat to the circulating water, and the stored hot water temperature continues to decrease. On the other hand, after the end of time interval T, the water heat exchanger inlet temperature becomes higher than the stored hot water temperature. Therefore, the circulating water continues to give heat to the stored hot water, and the stored hot water temperature continues to increase, while the rate of increase of the water heat exchanger inlet temperature decreases.

[0085] Returning to Fig. 3 , the timing at which the heater 13 turns ON will be described with reference to the timing chart in the lower part of Fig. 3 . As shown in the timing chart in Fig. 3 , when the operation mode switches from cooling operation to hot water supply operation, the compressor 23 turns from ON to OFF, and then, with a delayed timing, the first pump 45 turns from ON to OFF. When the first pump 45 turns OFF, the three-way valve 89 switches from the external device 5 side to the hot water supply tank 12 side. Then, the first pump 45 turns from OFF to ON again, and the heater 13 turns ON before the compressor 23 turns ON again.

[0086] Furthermore, during hot water supply operation in modes A to C, the control unit 10 turns on the heater 13 when the outdoor air temperature To is below a predetermined temperature. While this depends on the characteristics of the refrigeration circuit, including the refrigerant used, when the outdoor air temperature To drops below, for example, -10°C, the heat exchange efficiency between the air and the refrigerant in the air heat exchanger 25 significantly decreases. This may result in the refrigerant not being able to sufficiently heat the circulating water in the water heat exchanger 11. In this case, turning on the heater 13 further heats the circulating water, thereby boiling the hot water stored in the hot water supply tank 12 to the hot water supply setting temperature and preventing the time it takes for the hot water stored in the hot water supply tank 12 to reach the hot water supply setting temperature from becoming excessively long. Because the heater 13 is provided to compensate for insufficient heating by the heat pump, it is also commonly referred to as a backup heater.

[0087] 5, the timing for turning on the heater 13 when the outdoor air temperature To is equal to or lower than a predetermined temperature upon switching from heating operation to hot water supply operation in operation mode B will be described. In this case, the heating operation time setting value is set to Tm3s, and the hot water supply operation time setting value is set to Tm4s.

[0088] When the heating operation time setting value Tm3s has elapsed, the control unit 10 switches the operation mode from heating operation to hot water supply operation, and then turns on the heater 13 at the timing when the first pump 45 is turned on only when the outside air temperature To is below a predetermined temperature. Then, the compressor 23 is turned on. The control unit 10 heats the circulating water by keeping the heater 13 on as long as the outside air temperature To does not exceed the predetermined temperature. Then, when the hot water supply operation time setting value Tm4s has elapsed, the control unit 10 turns off the heater 13 when the operation mode is switched from hot water supply operation to heating operation. The heater 13 may be turned on not only during hot water supply operation, but also during heating operation if the outside air temperature To is lower than the predetermined temperature.

[0089] The series of operations in the air conditioning and hot water supply system 1 according to this embodiment described above are executed by the control unit 10 of the air conditioning and hot water supply system 1. The processing in this control unit 10 will be described using the flowcharts shown in Figures 6 to 8. The symbols and names shown in Figures 6 to 8 are defined as follows:

[0090] Timer Tm1 measures the cooling operation time, which is the duration of cooling operation during execution of mode A, an operation mode that alternates between cooling operation and hot water supply operation at predetermined time intervals. Timer Tm2 measures the hot water supply operation time, which is the duration of hot water supply operation during execution of mode A. Timer Tm3 measures the heating operation time, which is the duration of heating operation during mode B, an operation mode that alternates between heating operation and hot water supply operation at predetermined time intervals. Timer Tm4 measures the hot water supply operation time, which is the duration of hot water supply operation during mode B.

[0091] The cooling operation time set value Tm1s when mode A is executed is, for example, 30 minutes. The hot water operation time set value Tm2s when mode A is executed is, for example, 20 minutes. The heating operation time set value Tm3s when mode B is executed is, for example, 30 minutes. The hot water operation time set value Tm4s when mode B is executed is, for example, 15 minutes.

[0092] The compressor start delay time Tmc is the minimum time required between the stoppage of the compressor 23 and the next start-up, and is set to, for example, 1 minute 20 seconds. The compressor start delay time Tmc is set to reduce the pressure difference between the suction side and the discharge side when the compressor 23 starts up.

[0093] The pump stop delay time Tmp1 of the first pump 45 is, for example, 20 seconds. The pump start delay time Tmp2 of the first pump 45 when mode A is executed is, for example, 25 seconds, which is the pump stop delay time Tmp1 plus 5 seconds. The pump start delay time Tmp3 of the first pump 45 when mode B is executed is, for example, 5 seconds.

[0094] 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. In other words, the heater 13 turns on 5 seconds after the first pump 45 turns on. The heater operation time setting value Tmh2 of the heater 13 is, for example, a value set in advance in the device, such as 3 to 5 minutes. The outside air temperature setting value Tos is, for example, -10°C.

[0095] The stored hot water temperature Tt is detected by the hot water tank temperature sensor 69 and sent to the control unit 10. The water heat exchanger inlet temperature Twi is detected by the inlet temperature sensor 52.

[0096] The compressor 23 is represented as "COMP" and the four-way valve 29 as "FWV". Switching the four-way valve 29 to heating is represented as "HEATING", and switching it to cooling is represented as "COOLING". The first pump 45 is represented as "P", and the three-way valve 89 is represented as "TWV". Switching the three-way valve 89 to the hot water tank 12 side is represented as "HWST", and switching it to the external device 5 side is represented as "ED". The heater 13 is represented as "H".

[0097] Step S1 will be abbreviated as "S1." Steps S2 and onward will be abbreviated in the same manner.

[0098] 6, first, in S1, the control unit 10 determines whether or not the operation mode has been changed. The operation mode is changed as shown in Table 1 depending on the operation of the user, the status of the external device 5, or the hot water tank 12. If the operation mode has been changed (YES in S1), the process proceeds to S2, and if the operation mode has not been changed (NO in S1), the process proceeds to S3.

[0099] In S2 following YES in S1, in order to change the operation mode, initialization processing is performed on the states of the respective control targets, namely the compressor 23, the four-way valve 29, the first pump 45, the three-way valve 89, and the heater 13, before proceeding to S3. In the initialization processing, the compressor 23 is turned off, the four-way valve 29 is switched to cooling, the first pump 45 is turned off, the three-way valve 89 is switched to the external device 5 side, and the heater 13 is turned off.

[0100] In S3 following NO in S1 or S2, the control unit 10 determines the operation mode. If the operation mode is mode A, the process proceeds to S21 in Fig. 7. If the operation mode is mode B, the process proceeds to S51 in Fig. 8. If the operation mode is mode C, the process proceeds to S4. If the operation mode is mode D, the process proceeds to S5. If the operation mode is mode E, the process proceeds to S6. If the operation mode is stop, the controlled object has already been initialized in S2 and is in a stop state, so the process proceeds to S10.

[0101] In S4, that is, when the operation mode is mode C, the compressor 23 is turned on, the four-way valve 29 is switched to heating, the first pump 45 is turned on, and the three-way valve 89 is switched to the hot water tank 12 side.

[0102] In S5, that is, when the operating mode is mode D, the compressor 23 is turned ON, the four-way valve 29 is switched to cooling, the first pump 45 is turned ON, the three-way valve 89 is switched to the external device 5 side, and the heater 13 is turned OFF.

[0103] In S6, that is, when the operation mode is mode E, the compressor 23 is turned ON, the four-way valve 29 is switched to heating, the first pump 45 is turned ON, the three-way valve 89 is switched to the external device 5 side, and the heater 13 is turned OFF.

[0104] In S7 following S4, it is determined whether the outside air temperature To is equal to or lower than the set outside air temperature Tos. If the outside air temperature To is equal to or lower than the set outside air temperature Tos (YES in S7), the process proceeds to S8, where the heater 13 is turned on. On the other hand, if the outside air temperature To is higher than the set outside air temperature Tos (NO in S7), the process proceeds to S9, where the heater 13 is turned off.

[0105] In S8, if the heater 13 has already been turned on in a step prior to S8, the heater 13 is maintained in the on state.

[0106] Similarly, in S9, if the heater 13 has already been turned off in a step prior to S9, the heater 13 remains in the off state.

[0107] In S10 following S5, S6, S8 or S9, the timers Tm1 to Tm4 that may have been operating in the previous control are reset to stop timing, and the process returns to the start.

[0108] Next, the operation of each component in mode A (cooling / hot water supply switching operation) will be described with reference to FIG.

[0109] First, in S21, the control unit 10 determines whether the timer Tm1 is operating. If the timer Tm1 is operating (YES in S21), the process proceeds to S22. If the timer Tm1 is not operating (NO in S21), the process proceeds to S37. Immediately after changing the operating mode, each timer is reset in S10, so the process proceeds from S21 to S37.

[0110] In S22, it is determined whether the time count of the timer Tm1 in operation is equal to or greater than the cooling operation time setting Tm1s. If the time count of the timer Tm1 is equal to or greater than the cooling operation time setting Tm1s (YES in S22), the process proceeds to S23 to terminate the cooling operation and start the hot water supply operation. If the time count of the timer Tm1 is less than the cooling operation time setting Tm1s (NO in S22), the cooling operation continues, and the process returns to the start of FIG. 6 and proceeds to S1.

[0111] In S23, the control unit 10 turns off the compressor 23 and the heater 13. In the following S24, the control unit 10 resets the timer Tm1 to stop timing, and starts timing of the timer Tm2.

[0112] In the next step S25, it is determined whether the time counted by the timer Tm2 is equal to or greater than the pump stop delay time Tmp1. If the time counted by the timer Tm2 is equal to or greater than the pump stop delay time Tmp1 (YES in S25), the process proceeds to S26. If the time counted by the timer Tm2 is less than the pump stop delay time Tmp1 (NO in S25), S25 is repeated to wait for the timer Tm2 to elapse.

[0113] In S26, the first pump 45 is turned OFF, and the three-way valve 89 is switched to the hot water tank 12 side. In S27 following S26, the control unit 10 determines whether the time counted by the timer Tm2 is equal to or greater than the pump start delay time Tmp2. If the time counted by the timer Tm2 is equal to or greater than the pump start delay time Tmp2 (YES in S27), the process proceeds to S28, where the first pump 45 is turned ON. On the other hand, if the time counted by the timer Tm2 is less than the pump start delay time Tmp2 (NO in S27), S27 is repeated to wait for the timer Tm2 to elapse.

[0114] In S29 following S28, it is determined whether the time counted by the timer Tm2 is equal to or greater than the heater startup delay time Tmh1. If the time counted by the timer Tm2 is equal to or greater than the heater startup delay time Tmh1 (YES in S29), the process proceeds to S30, where the heater 13 is turned on. If the time counted by the timer Tm2 is less than the heater startup delay time Tmh1 (NO in S29), S29 is repeated to wait for the timer Tm2 to elapse.

[0115] In S31 following S30, it is determined whether the time counted by the timer Tm2 is equal to or greater than the compressor start-up delay time Tmc. If the time counted by the timer Tm2 is equal to or greater than the compressor start-up delay time Tmc (YES in S31), the process proceeds to S32, where the compressor 23 is turned on and the four-way valve 29 is switched to heating. On the other hand, if the time counted by the timer Tm2 is less than the compressor start-up delay time Tmc (NO in S31), S31 is repeated to wait for the timer Tm2 to elapse.

[0116] In S33 following S32, the control unit 10 determines whether the time count of the timer Tm2 is equal to or greater than the heater operation time setting Tmh2. If the time count of the timer Tm2 is equal to or greater than the heater operation time setting Tmh2 (YES in S33), the control unit 10 proceeds to S34. If the time count of the timer Tm2 is less than the heater operation time setting Tmh2 (NO in S33), the control unit 10 repeats S33 and waits for the timer Tm2 to elapse.

[0117] In S34 following YES in S33 or NO in S38, the control unit 10 determines whether the outside air temperature To is equal to or lower than the set outside air temperature Tos. If the outside air temperature To is equal to or lower than the set outside air temperature Tos (YES in S34), the control unit 10 proceeds to S35, where the heater 13 is turned on or kept on. If the outside air temperature To is higher than the set outside air temperature Tos (NO in S34), the control unit 10 proceeds to S36, where the heater 13 is turned off.

[0118] After the processing of S35 and S36, the process returns to the start of FIG. 6 and proceeds to S1.

[0119] If S21 is NO, i.e., if timer Tm1 is not running, the process proceeds to S37, which determines whether timer Tm2 is running. If timer Tm2 is running (YES in S37), the process proceeds to S38. If timer Tm2 is not running (NO in S37), the process proceeds to S41. Note that if timer Tm2 is not running in S37, this means that the air conditioning and hot water supply system 1 has not yet started mode A, that is, this is the first time the system has switched to mode A from another mode.

[0120] In S38, it is determined whether the time count of the timer Tm2 is equal to or greater than the hot water supply operation time setting Tm2s. If the time count of the timer Tm2 is equal to or greater than the hot water supply operation time setting Tm2s (YES in S38), the process proceeds to S39, where the compressor 23 is turned off and the heater 13 is turned off. If the time count of the timer Tm2 is less than the hot water supply operation time setting Tm2s (NO in S38), the process proceeds to S34.

[0121] In S40 following S39, the timer Tm2 is reset to stop timing, and in the following S41, the timer Tm1 is started to count time.

[0122] Next, in S42, it is determined whether the time counted by the timer Tm1 is equal to or greater than the pump stop delay time Tmp1. If the time counted by the timer Tm2 is equal to or greater than the pump stop delay time Tmp1 (YES in S42), the first pump 45 is turned off and the three-way valve 89 is switched to the side of the external device 5 in S43. On the other hand, if the time counted by the timer Tm1 is less than the pump stop delay time Tmp1 (NO in S42), S42 is repeated to wait for the timer Tm1 to elapse.

[0123] In S44 following S43, it is determined whether the time counted by the timer Tm1 is equal to or greater than the pump start delay time Tmp2. If the time counted by the timer Tm1 is equal to or greater than the pump start delay time Tmp2 (YES in S44), the process proceeds to S45, where the first pump 45 is turned on. If the time counted by the timer Tm1 is less than the pump start delay time Tmp2 (NO in S44), S44 is repeated to wait for the timer Tm1 to elapse.

[0124] In S46 following S45, the control unit 10 determines whether the time counted by the timer Tm1 is equal to or greater than the compressor start-up delay time Tmc. If the time counted by the timer Tm1 is equal to or greater than the compressor start-up delay time Tmc (YES in S46), the control unit 10 proceeds to S47. If the time counted by the timer Tm1 is less than the compressor start-up delay time Tmc (NO in S46), the control unit 10 repeats S46 and waits for the timer Tm1 to elapse.

[0125] In S47, the compressor 23 is turned on, the four-way valve 29 is switched to cooling, and the process returns to the start of FIG. 6 and proceeds to S1.

[0126] By the sequence control of S21 to S47 described above, the cooling operation for the cooling operation time set value Tm1s and the hot water supply operation for the hot water supply operation time set value Tm2s are alternately repeated to execute the operation of mode A.

[0127] Next, the operation of each component in mode B (heating / hot water supply switching operation) will be described with reference to FIG.

[0128] First, in S51, the control unit 10 determines whether the timer Tm3 is running. If the timer Tm3 is running (YES in S51), the process proceeds to S52. If the timer Tm3 is not running (NO in S51), the process proceeds to S61.

[0129] In S52, it is determined whether the time count of the timer Tm3 is equal to or greater than the heating operation time setting value Tm3s. If the time count of the timer Tm3 is equal to or greater than the heating operation time setting value Tm3s (YES in S52), the process proceeds to S53, where the compressor 23 is turned off and the heater 13 is turned off. On the other hand, if the time count of the timer Tm3 is less than the heating operation time setting value Tm3s (NO in S52), the process proceeds to S58.

[0130] In S54 following S53, the timer Tm3 is reset to stop timing, and the timer Tm4 is started to start timing.

[0131] In S55 following 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 hot water supply tank 12 side.

[0132] Next, in S56, it is determined whether the time counted by the timer Tm4 is equal to or greater than the pump start delay time Tmp3. If the time counted by the timer Tm4 is equal to or greater than the pump start delay time Tmp3 (YES in S56), the process proceeds to S57, where the first pump 45 is turned on. If the time counted by the timer Tm4 is less than the pump start delay time Tmp3 (NO in S56), S56 is repeated to wait for the timer Tm4 to elapse.

[0133] In S58 following S52 (NO) or S57, it is determined whether the outside air temperature To is equal to or lower than the set outside air temperature Tos. If the outside air temperature To is equal to or lower than the set outside air temperature Tos (YES in S58), the process proceeds to S59, where the heater 13 is turned on as a measure against the low outside air temperature, and the process returns to START in Fig. 6 and proceeds to S1. If the outside air temperature To is higher than the set outside air temperature Tos (NO in S58), the process proceeds to S60, where the heater 13 is turned off or kept off, and the process returns to START in Fig. 6 and proceeds to S1.

[0134] If timer Tm3 is not operating (NO in S51), it is determined in S61 whether timer Tm4 is operating. If timer Tm4 is operating (YES in S61), the process proceeds to S62. If timer Tm4 is not operating (NO in S61), the process proceeds to S65. Note that when timer Tm4 is not operating, this means that the air conditioning and hot water supply system 1 has not yet started mode B, i.e., this is the first time the system has transitioned to mode B from another mode.

[0135] In S62, the control unit 10 determines whether the time count of the timer Tm4 is equal to or greater than the hot water supply operation time setting Tm4s. If the time count of the timer Tm4 is equal to or greater than the hot water supply operation time setting Tm4s (YES in S62), the process proceeds to S63, where the compressor 23 is turned off and the heater 13 is turned off. If the time count of the timer Tm4 is less than the hot water supply operation time setting Tm4s (NO in S62), the process returns to the start of FIG. 6 and proceeds to S1.

[0136] In S64 following S63, the timer Tm4 is reset to stop timing.

[0137] In S65 following NO in S61 or S64, the timer Tm3 is started to count time.

[0138] In S66 following S65, the four-way valve 29 is switched to heating or maintained in heating, the first pump 45 is turned off, the three-way valve 89 is switched to the external device 5 side, and the heater 13 is turned off.

[0139] In S67 following S66, the control unit 10 determines whether the time counted by the timer Tm3 is equal to or greater than the pump start delay time Tmp3. If the time counted by the timer Tm3 is equal to or greater than the pump start delay time Tmp3 (YES in S67), the first pump 45 is turned on in S68, and the process returns to START in Fig. 6 and proceeds to S1. If the time counted by the timer Tm3 is less than the pump start delay time Tmp3 (NO in S67), S67 is repeated to wait for the timer Tm3 to elapse.

[0140] As explained above, the control unit 10 determines each operating mode according to the control flows of Figures 6 to 8, and controls each component based on the determination result, so that the air conditioning and hot water supply system 1 operates in the desired operating mode.

[0141] As described above, the control unit 10 of the air conditioning and hot water supply system 1 according to this embodiment turns on the heater 13 for a predetermined time when switching from cooling operation to hot water supply operation in operation mode A. The heater 13 further heats the circulating water that has been heated by the refrigerant in the water heat exchanger 11. In other words, by using the heater 13 in combination with the heat pump, the air conditioning and hot water supply system 1 can increase the heating capacity of the circulating water, which is the heat medium, prevent a drop in the temperature of the hot water stored in the hot water tank 12, and shorten the time it takes for the stored hot water temperature to reach the hot water setting temperature.

[0142] Furthermore, when switching from cooling operation to hot water supply operation, the control unit 10 energizes (ON) the heater 13 for a period from a predetermined heater start delay time Tmh1 to a heater operation time setting value Tmh2 (S29 to S33). However, if the temperature of the circulating water is high, this amount of power consumption by the heater 13 may be wasted. Therefore, S33 in FIG. 7 may be changed to S33' to shorten the energization time of the heater 13. In S33', the heater 13 is turned OFF when the water heat exchanger inlet temperature Twi detected by the inlet temperature sensor 52 becomes equal to or higher than the stored hot water temperature Tt.

[0143] As explained in Figure 4, once the water heat exchanger inlet temperature becomes equal to or higher than the stored hot water temperature, the stored hot water temperature will not decrease. Therefore, when the water heat exchanger inlet temperature becomes equal to or higher than the stored hot water temperature (point Q in Figure 2), the control unit 10 turns off the heater 13. This shortens the time that power is supplied to the heater 13 compared to when the heater 13 is turned on for only a predetermined time in S33, while reducing the decrease in the stored hot water temperature, thereby suppressing unnecessary temperature rise of the circulating water and power consumption.

[0144] In this embodiment, the first pump 45 and the heater 13 are turned on when switching from cooling operation to hot water operation in the cooling / hot water switching operation of operation mode A. However, the first pump 45 and the heater 13 may be turned on in the same manner not only during operation in operation mode A, but also when transitioning from operation mode D, which performs only cooling operation, to operation mode C, which performs only hot water operation. However, in actual operation of the air conditioning and hot water supply system 1, there is almost no possibility of transitioning from operation mode D to operation mode C.

[0145] Originally, heater 13 was provided as a backup to supplement the heating capacity of the heat pump, even when the heating capacity of the heat pump is reduced due to a drop in the outdoor air temperature To during hot water supply operation, to heat the hot water stored in hot water tank 12 to the hot water supply setting temperature and prevent the time it takes for the stored hot water temperature to reach the hot water supply setting temperature from becoming excessively long. For this reason, when the outdoor air temperature To is equal to or lower than the outdoor air temperature setting Tos during hot water supply operation, heater 13 is turned on (S34 to S36 in FIG. 7 and S58 to S60 in FIG. 8). This prevents the temperature of the hot water stored in hot water tank 12 from dropping, resulting in low-temperature hot water being dispensed from faucets and showers, a situation known as "hot water shortage." Therefore, in the air conditioning and hot water supply system 1 of this embodiment, when the outside air temperature To is below the predetermined outside air temperature set value Tos, the heater 13 provided to supplement the heating capacity of the heat pump is effectively utilized to prevent the temperature of the stored hot water in the hot water supply tank 12 from dropping when switching from air conditioning operation to hot water supply operation, thereby achieving the new effect of shortening the time it takes for the stored hot water temperature to reach the hot water supply set temperature.

[0146] In another embodiment of the air conditioning and hot water supply system 1, the outdoor unit 2 may include all of the components of the heat exchange unit 3 located on the water heat exchanger 11 side of 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 circulating water flows, and no piping for refrigerant is connected. In this case, the piping through which circulating water flows is exposed to the outdoors, and there is a risk that the circulating water in the piping may freeze while the air conditioning and hot water supply system 1 is stopped. Therefore, by operating the heater 13 and first pump 45 provided in the outdoor unit 2 when the outdoor temperature To is low, the circulating water in the piping is prevented from freezing at low outdoor temperatures.

[0147] In yet another embodiment of the air conditioning and hot water supply system 1, only the water heat exchanger 11 may be moved 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 heater 13, first pump 45, and expansion tank 49 located between the wavy lines P3 and P4 in FIG. 1 , excluding the water heat exchanger 11. In this case, because the outdoor unit 2 and the indoor unit are connected by piping through which circulating water flows, it is important to note that measures to prevent the circulating water in the piping from freezing are required, as in the previous embodiment. Separating the hot water tank 12 from the heat exchange unit 3 at the wavy lines P5 and P6 in FIG. 1 may separate the heat exchange unit 3 and the hot water tank 12, thereby increasing the flexibility in the installation location of the heat exchange unit 3 and the hot water tank 12.

[0148] The position of the three-way valve 89, which is a flow path switching device for the circulating water, may be moved to the branch point Z, and the original position of the three-way valve 89 may be changed to the branch point (junction point). That is, the position of the branch point Z may be interchanged with the position of the three-way valve 89. In this case, the common path 41a is the outward pipe 81 from the water heat exchanger 11 to the three-way valve 89 and the return pipe 83 from the branch point Z, which is also the junction point, to the water heat exchanger 11.

[0149] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0150] 1...Air conditioning and hot water supply system, 2...Outdoor unit, 3...Heat exchange unit, 5...External device, 10...Control unit, 11...Water heat exchanger (heat medium heat exchanger), 12...Hot water supply tank, 13...Heater, 14...Refrigerant pipe, 21...Refrigeration circuit, 23...Compressor, 25...Air heat exchanger, 26...Outdoor air temperature sensor (temperature sensor), 29...Four-way valve, 41...Heat medium circulation circuit, 41a...Common path, 41b...First heat medium circulation circuit, 41c...Second heat medium circulation circuit, 45...First pump, 51...Outlet temperature sensor, 52...Inlet temperature sensor, 69...Hot water supply tank temperature sensor, 89...Three-way valve (flow path switching device).

Claims

1. An air conditioning and hot water supply system comprising: a refrigeration circuit having a heat medium heat exchanger that exchanges heat between a refrigerant and a heat medium, and capable of heating and cooling the heat medium by the refrigerant in the heat medium heat exchanger; a common path connected to the user side of the heat medium heat exchanger, through which the cooled heat medium flows during cooling operation using the heat medium cooled in the refrigeration circuit, and through which the heated heat medium flows during hot water supply operation using the heat medium heated in the refrigeration circuit; a heater that heats the heat medium; and a control unit that controls the refrigeration circuit and the heater, wherein the control unit turns on the heater for a predetermined period of time when switching from the cooling operation to the hot water supply operation.

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

3. An air conditioning and hot water system as described in claim 2, comprising: a hot water tank connected to the second heat medium circulation circuit for exchanging heat between the heated heat medium and stored hot water; and a hot water tank temperature sensor provided in the hot water tank for detecting the temperature of the hot water stored in the hot water tank.

4. An air conditioning and hot water system as described in claim 3, further comprising an inlet temperature sensor provided at the inlet of the heat medium of the heat medium heat exchanger, and the specified time is the time until the temperature of the heat medium detected by the inlet temperature sensor becomes equal to or higher than the stored hot water temperature detected by the hot water tank temperature sensor.

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

6. An air conditioning and hot water supply system as described in any one of claims 2 to 5, wherein the refrigeration circuit is provided with a compressor that compresses the refrigerant, and the control unit, when switching from the cooling operation to the hot water supply operation, turns the pump OFF once and then ON again, and then turns the heater ON before turning on the compressor.

7. An air conditioning and hot water supply system as described in any one of claims 1 to 6, wherein the refrigeration circuit is provided with an air heat exchanger that exchanges heat between the refrigerant and surrounding air, and a temperature sensor that detects the ambient temperature of the location where the air heat exchanger is installed, and the control unit turns on the heater when the ambient temperature detected by the temperature sensor during the hot water supply operation is equal to or lower than a predetermined temperature.

8. An air conditioning and hot water supply system as described in any one of claims 1 to 7, wherein when there is a simultaneous request for the cooling operation and the hot water supply operation, the control unit alternates between the cooling operation and the hot water supply operation at a predetermined time interval.

9. An air conditioning and hot water supply system as described in any one of claims 2 to 6, comprising a heat exchange unit that houses the heat medium heat exchanger, the common path, a part of the first heat medium circulation circuit, the second heat medium circulation circuit, the flow path switching device, the pump, and the heater.

10. An air conditioning and hot water supply system as described in claim 3 or claim 4, comprising a heat exchange unit that houses the heat medium heat exchanger, the common path, a part of the first heat medium circulation circuit, the second heat medium circulation circuit, the flow path switching device, the pump, the heater, and the hot water tank.

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