Air conditioning system

Abstract

To provide an air-conditioning system capable of: heating or cooling a heat medium to be distributed to an air-conditioning device using either one or both of two heat sources, a first heat source and a second heat source; and curbing radiation heat loss and pressure loss in a flow passage to circulate the heat medium through the air-conditioning device.SOLUTION: An air-conditioning system 1 comprises: a heat medium circuit 40 which connects a first heat source 10 and a second heat source 20 in parallel to each other with respect to air-conditioning devices 2 and 3 so as to circulate a heat medium between either one or both of the first heat source 10 and the second heat source 20 and the air-conditioning devices 2 and 3; and a flow passage switching device 45 which switches a flow passage in the heat medium circuit 40. By switching the flow passage, the air-conditioning system is capable of executing cooling operation with the heat medium cooled with the first heat source 10 and heating operation with the heat medium heated with either one or both of the first heat source 10 and the second heat source 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system that uses a heat medium. [Background technology]

[0002] Conventionally, as seen in Patent Documents 1 and 2, for example, air conditioning systems have been known in which a flow path for circulating a heat medium in an air conditioning device such as a heating terminal is configured so that the heat medium flows in series through a heat exchanger of a heat pump and a heat exchanger heated by a burner. Patent Documents 1 and 2 describe techniques in which, during heating operation of the air conditioning device, the heat medium supplied to the air conditioning device is normally heated only by a heat pump, and in cases such as when the amount of heat in the heat medium is insufficient, the heat medium is heated by both the heat pump and a burner. Patent Document 1 also describes heating the heat medium only by a burner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-287530 [Patent Document 2] Japanese Patent Application Publication No. 2019-49383 Summary of the Invention [Problem to be solved by the invention]

[0004] As seen in Patent Documents 1 and 2, when a heat transfer medium is circulated in series through a heat pump heat exchanger and a heat exchanger heated by a burner, the path length of the heat transfer medium discharged from the air conditioning device until it returns to the air conditioning device tends to be long, which is disadvantageous in that it is likely to cause heat radiation loss and pressure loss.

[0005] In particular, as seen in Patent Document 2, in an air conditioning system in which a heat medium always flows in series through a heat pump heat exchanger and a heat exchanger heated by a burner, even when the heat medium is heated by only one of the heat pump and the burner, the heat medium is forced to flow through the heat exchanger on the other side, which tends to result in large heat loss.In addition, when attempting to operate the air conditioning system in cooling mode, the heat medium cooled by the heat pump passes through the heat exchanger on the burner side, which tends to cause deterioration of the heat exchanger due to condensation, etc.

[0006] The present invention has been made in consideration of the above background, and aims to provide an air conditioning system that can heat or cool a heat medium circulating in an air conditioning device using one or both of two heat sources, a first heat source and a second heat source, and that can suppress heat dissipation loss and pressure loss in the flow path that circulates the heat medium through the air conditioning device. [Means for solving the problem]

[0007] In order to achieve the above object, the air conditioning system of the present invention comprises: A first heat source capable of heating or cooling a heat medium; a second heat source capable of heating the heat medium; an air conditioning device that performs heat exchange between the heat medium and the indoor space to air-condition the indoor space; a heat medium circuit that connects the first heat source and the second heat source in parallel to the air conditioner so as to circulate the heat medium between the air conditioner and one or both of the first heat source and the second heat source; a flow path switching device configured with one or more switching valves provided in the heat medium circuit, the flow path switching device being selectively operable between a first operating state forming a flow path for circulating the heat medium between the first heat source and the air conditioning device without passing through the second heat source, a second operating state forming a flow path for circulating the heat medium between the second heat source and the air conditioning device without passing through the first heat source, and a third operating state forming a flow path for circulating the heat medium between both the first heat source and the second heat source and the air conditioning device, The present invention is characterized in that it is configured to be able to perform the following operations: a cooling operation in which, with the flow path switching device operating in the first operating state, the heat medium is circulated between the first heat source and the air conditioning device and cooled by the first heat source; a first heating operation in which, with the flow path switching device operating in the first operating state, the heat medium is circulated between the first heat source and the air conditioning device and heated by the first heat source; a second heating operation in which, with the flow path switching device operating in the second operating state, the heat medium is circulated between the second heat source and the air conditioning device and heated by the second heat source; and a third heating operation in which, with the flow path switching device operating in the third operating state, the heat medium is circulated between both the first heat source and the second heat source and the air conditioning device and heated by the first heat source and the second heat source (first invention).

[0008] According to the first invention, the flow path of the heat medium in the heat medium circuit can be switched by switching the operating state of the flow path switching device, so it is possible to perform a cooling operation in which a heat medium cooled by a first heat source is circulated through an air conditioning device, a first heating operation in which a heat medium heated only by the first heat source of the first and second heat sources is circulated through an air conditioning device, a second heating operation in which a heat medium heated only by the second heat source of the first and second heat sources is circulated through an air conditioning device, and a third heating operation in which a heat medium heated by both the first and second heat sources is circulated through an air conditioning device.

[0009] In this case, since the first heat source and the second heat source are connected in parallel to the air conditioner, it is possible to configure the path length of the flow path for circulating the heat medium between the first heat source and the air conditioner and the path length of the flow path for circulating the heat medium between the second heat source and the air conditioner to be short, which in turn makes it possible to suppress heat radiation loss and pressure loss in these flow paths. Therefore, according to the first aspect of the present invention, it is possible to heat or cool the heat medium circulating in the air conditioner, and it is also possible to suppress heat radiation loss and pressure loss in the flow path that circulates the heat medium through the air conditioner.

[0010] In the first invention, the heat medium circuit can be configured as a circuit including: a first outbound path connected to the first heat source so as to send out the heat medium from the first heat source; a first return path connected to the first heat source so as to return the heat medium to the first heat source; a second outbound path connected to the second heat source so as to send out the heat medium from the second heat source; a second return path connected to the second heat source so as to return the heat medium to the second heat source; a heat medium supply path connected to the first outbound path and the second outbound path so as to merge the first outbound path and the second outbound path, and connected to the air conditioner so as to supply the heat medium to the air conditioner; and a heat medium discharge path connected to the air conditioner so as to discharge the heat medium from the air conditioner, and branched into the first return path and the second return path (second invention). This makes it possible to realize a heat medium circuit that connects the first heat source and the second heat source in parallel to the air conditioner.

[0011] In the first or second invention, it is preferable that the heat medium circuit includes a first pump provided in a flow path of the heat medium circuit that passes only the first heat source of the first and second heat sources, and a second pump provided in a flow path of the heat medium circuit that passes only the second heat source of the first and second heat sources (third invention).

[0012] This makes it possible to increase or decrease the flow rate of the heat medium passing through the first heat source and the flow rate of the heat medium passing through the second heat source separately depending on the operating state of the air conditioner, particularly in the third heating operation. Also, even if one of the first pump and the second pump breaks down, it is possible to supply the heat medium heated by the heat source corresponding to the other pump (normal pump) of the first heat source and the second heat source to the air conditioner, and to operate the air conditioner (heating operation).

[0013] The third invention described above may employ an embodiment in which the air conditioning system is provided with a required heat quantity determination unit that determines the required heat quantity of the air conditioning system in accordance with the temperature state requirements of the indoor space, and a control unit that controls the heat quantities of the first heat source and the second heat source and the operation of the first pump and the second pump, and when switching from the first heating operation to the third heating operation due to an increase in the required heat quantity of the air conditioning system during execution of the first heating operation, the control unit is configured to control the heat quantity of the second heat source and the rotation speed of the second pump so as to achieve the increased required heat quantity of the air conditioning system while maintaining the heat quantity of the first heat source and the rotation speed of the first pump at the same state as during the first heating operation (fourth invention).

[0014] According to this, when switching from the first heating operation to the third heating operation due to an increase in the heat demand of the air conditioner during the first heating operation, the heat demand of the second heat source and the rotation speed of the second pump are controlled to realize the increased heat demand of the air conditioner while maintaining the heat demand of the first heat source and the rotation speed of the first pump at the same levels as during the first heating operation. This allows for simple operation control of the first and second heat sources and the first and second pumps. Furthermore, the heat demand of the second heat source and the rotation speed of the second pump are increased while maintaining the heat demand of the first heat source and the rotation speed of the first pump. This makes it possible to suppress excessive transient fluctuations in the temperature of the heat medium supplied to the air conditioner, compared to changing not only the heat demand of the second heat source and the rotation speed of the second pump but also the heat demand of the first heat source and the rotation speed of the first pump. This ultimately allows for a smooth change in the operating state of the air conditioner due to an increase in the heat demand.

[0015] In the first to fourth aspects of the present invention, the second heat source may have a heating section for heating a heat medium, which includes a low-temperature heating section for heating the heat medium to a lower temperature and a high-temperature heating section for heating the heat medium to a higher temperature, and the heat medium circuit may include a flow path that passes through the second heat source and passes through the low-temperature heating section, and the high-temperature heating section may be connected to a heat dissipation device via a circulation path so as to circulate the heat medium between the heat medium heated to the high-temperature temperature and the heat dissipation device. In this case, it is preferable that the circulation path is configured so that the heat medium supplied from the high-temperature heating section to the heat dissipation device does not flow into the heat medium circuit (a fifth aspect of the present invention).

[0016] This prevents the high-temperature heat transfer medium supplied from the high-temperature heating section to the heat transfer device from flowing into the heat transfer medium circuit during operation of the heat transfer device, thereby preventing a heat transfer medium with a temperature higher than the low-temperature heat transfer medium from being supplied to the air conditioner during cooling or heating operation of the air conditioner. As a result, the heat transfer device can be operated while the air conditioner is operating properly in cooling or heating mode. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing the configuration of an air conditioning system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a configuration related to operation control of the air conditioning system according to the embodiment. [Figure 3] FIG. 4 is a diagram showing the configuration of an air conditioning system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] [First embodiment] A first embodiment of the present invention will be described below with reference to Figures 1 and 2. As shown in Figure 1, air conditioning system 1 of this embodiment is a system that includes, as air conditioning devices, a heating air conditioner 2, a cooling and heating air conditioner 3, and a bathroom heater 4, as well as a heat pump unit 10 as a first heat source that can heat or cool a heat medium, and a combustion heat source machine 20 as a second heat source that can heat the heat medium. The heat medium in this air conditioning system 1 can be, for example, water or antifreeze.

[0019] Heating air conditioner 2, cooling and heating air conditioner 3, and bathroom heating unit 4 are all well-known air conditioners that have flow paths (not shown) for circulating a heat transfer medium and heat or cool the indoor space in which they are located by exchanging heat between the heat transfer medium flowing through the flow path and the indoor space in which they are located. Heating air conditioner 2 is an air conditioner that heats the indoor space in which it is located and is composed of, for example, a fan convector, a panel heater, or a floor heating unit. Heating and cooling air conditioner 3 is an air conditioner that cools or cools the indoor space in which it is located and is composed of, for example, a fan coil unit. Bathroom heating unit 4 is an air conditioner that can heat, dry, ventilate, etc. the bathroom in which it is located.

[0020] In this embodiment, the elements corresponding to the air conditioners of the present invention are heating air conditioner 2 and cooling / heating air conditioner 3, and bathroom heating device 4 corresponds to the heat dissipation device of the present invention. In the following description, when there is no need to distinguish between heating air conditioner 2 and cooling / heating air conditioner 3, they will be simply referred to as air conditioners 2 and 3.

[0021] The heat pump unit 10 includes a heat pump 11 of known configuration. The heat pump 11 includes a heat medium-side heat exchanger 12 and a refrigerant circuit 13 including a compressor, an outdoor air-side heat exchanger, and an expansion mechanism (not shown). In this case, the refrigerant circuit 13 can circulate the refrigerant from the outdoor air-side heat exchanger through the compressor, the heat medium-side heat exchanger 12, and the expansion mechanism in this order. In this state, heat absorbed by the refrigerant from the outdoor air via the outdoor air-side heat exchanger is dissipated via the heat medium-side heat exchanger 12 to a heat medium flowing through a heat medium circuit 40 (described later), thereby heating the heat medium.

[0022] The refrigerant circuit 13 can also circulate the refrigerant from the heat medium-side heat exchanger 12 through the compressor, the outdoor air-side heat exchanger, and the expansion mechanism in that order. In this state, the heat medium can be cooled by radiating heat from the heat medium flowing through the heat medium circuit 40 (described later) absorbed by the refrigerant via the heat medium-side heat exchanger 12 to the outdoor air via the outdoor air-side heat exchanger. Therefore, the heat pump unit 10 functions as a heat source capable of heating or cooling the heat medium.

[0023] The combustion heat source machine 20 is equipped with a heating section for heating the heat medium, which includes a low-temperature side heating section 21a that heats the heat medium to a low-temperature side temperature (for example, a temperature of 40 to 60°C) and a high-temperature side heating section 21b that heats the heat medium to a high-temperature side temperature (for example, a temperature of 70 to 80°C) that is higher than the low-temperature side temperature.

[0024] The low-temperature side heating section 21a is composed of a first burner 22a and a first heat exchanger 23a heated by the heat of combustion thereof, and the high-temperature side heating section 21b is composed of a second burner 22b and a second heat exchanger 23b heated by the heat of combustion thereof. The first burner 22a and the second burner 22b are, for example, gas burners. A fuel supply device 24 that supplies fuel gas to the first burner 22a and the second burner 22b is configured to supply fuel gas to each of the first burner 22a and the second burner 22b from a fuel supply source (not shown) via a main fuel supply path 25 and separate secondary fuel supply paths 26a and 26b for the first burner 22a and the second burner 22b, respectively.

[0025] In this case, an on-off valve 27 capable of opening and closing main fuel supply passage 25 is installed in main fuel supply passage 25. Furthermore, an on-off valve 28a capable of opening and closing main fuel supply passage 26a on the first burner 22a side and a fuel adjustment valve 29a for adjusting the amount of fuel gas supplied to first burner 22a are installed in main fuel supply passage 26a. Similarly, an on-off valve 28b capable of opening and closing main fuel supply passage 26b on the second burner 22b side and a fuel adjustment valve 29b for adjusting the amount of fuel gas supplied to second burner 22b are installed in main fuel supply passage 26a. The on-off valves 27, 28a, 28b may be constituted by solenoid valves or the like, and the fuel adjustment valves 29a, 29b may be constituted by proportional valves or the like.

[0026] Therefore, the first burner 22a starts combustion operation by being ignited by an ignition device (not shown) while the on-off valves 27 and 28a are controlled to be open. During combustion operation of the first burner 22a, the combustion amount of the first burner 22a can be controlled by controlling the fuel adjustment valve 29a. Furthermore, the first burner 22a is extinguished by controlling the on-off valve 27 or 28a to be closed.

[0027] Similarly, the second burner 22b starts combustion operation by being ignited by an ignition device (not shown) while the on-off valves 27 and 28b are controlled to be open. During combustion operation of the second burner 22b, the combustion amount of the second burner 22b can be controlled by controlling the fuel adjustment valve 29b. Furthermore, the second burner 22b is extinguished by controlling the on-off valve 27 or 28b to be closed. The fuel for the first burner 22a and the second burner 22b is not limited to gaseous fuel, but may be liquid fuel such as kerosene.

[0028] The first heat exchanger 23a is connected to the heat medium circuit 40 described below so that the heat medium flows through the heat medium circuit 40, and is configured to heat the heat medium by radiating the combustion heat provided by the combustion operation of the first burner 22a to the heat medium.

[0029] Second heat exchanger 23b is connected to bathroom heating device 4 via circulation path 31, which circulates a heat medium between second heat exchanger 23b and bathroom heating device 4. Second heat exchanger 23b heats the heat medium returning from bathroom heating device 4 via circulation path 31 by radiating the combustion heat provided by the combustion operation of second burner 22b to the heat medium, and then sends the heated heat medium to bathroom heating device 4 via circulation path 31.

[0030] More specifically, the circulation path 31 includes an outbound path 31a that connects the downstream end of the second heat exchanger 23b (the downstream end of the heat medium flow path in the second heat exchanger 23b) to the bathroom heating device 4 so that the heat medium to be supplied to the bathroom heating device 4 flows from the second heat exchanger 23b to the bathroom heating device 4, and a return path 31b that connects the upstream end of the second heat exchanger 23b (the upstream end of the heat medium flow path in the second heat exchanger 23b) to the bathroom heating device 4 so that the heat medium discharged from the bathroom heating device 4 flows from the bathroom heating device 4 to the second heat exchanger 23b.

[0031] An electric pump 32 is attached to one of outgoing path 31a and return path 31b, for example return path 31b, as a power source for circulating the heat medium through circulation path 31. An on-off valve 33, such as a solenoid valve, is attached to one of outgoing path 31a and return path 31b, for example outgoing path 31a, to open and close it (and thus open and close circulation path 31). A temperature sensor 34 is attached to outgoing path 31a to detect the temperature of the heat medium supplied from second heat exchanger 23b to bathroom heating device 4.

[0032] The high-temperature side heating section 21b may be provided with a bypass path for flowing the heat medium from the return path 31b of the circulation path 31 to the outward path 31a, bypassing the second heat exchanger 23b, and a control valve for adjusting the ratio between the flow rate of the heat medium in the bypass path and the flow rate of the heat medium in the second heat exchanger 23b.

[0033] The heat medium-side heat exchanger 12 of the heat pump 11 and the first heat exchanger 23a of the low-temperature side heating section 21a of the combustion heat source unit 20 are connected in parallel to each of the air conditioners 2 and 3 via a heat medium circuit 40. The heat medium circuit 40 is configured to have a flow path that allows the heat medium to circulate between the heat medium-side heat exchanger 12 of the heat pump 11 and each of the air conditioners 2 and 3 without passing through the first heat exchanger 23a of the low-temperature side heating section 21a, and a flow path that allows the heat medium to circulate between the first heat exchanger 23a of the low-temperature side heating section 21a and each of the air conditioners 2 and 3 without passing through the heat medium-side heat exchanger 12 of the heat pump 11.

[0034] Specifically, the heat medium circuit 40 includes a first outward path 41a connected to the downstream end of the heat medium-side heat exchanger 12 (the downstream end of the heat medium flow path in the heat medium-side heat exchanger 12) as a flow path for sending out the heat medium from the heat medium-side heat exchanger 12, a first return path 41b connected to the upstream end of the heat medium-side heat exchanger 12 (the upstream end of the heat medium flow path in the heat medium-side heat exchanger 12) as a flow path for returning the heat medium to the heat medium-side heat exchanger 12, a second outward path 42a connected to the downstream end of the first heat exchanger 23a (the downstream end of the heat medium flow path in the first heat exchanger 23a) as a flow path for sending out the heat medium from the first heat exchanger 23a, and a first return path 41b connected to the upstream end of the heat medium-side heat exchanger 12 (the upstream end of the heat medium flow path in the first heat exchanger 23a). a second return path 42b connected to the upstream end of the first heat exchanger 23a (the upstream end of the heat medium flow path in the first heat exchanger 23a) as a flow path for returning the heat medium to the heat exchanger 23a; a heat medium supply path 43a connected to the upstream ends of the air conditioners 2 and 3 (the upstream ends of the heat medium flow path in each of the air conditioners 2 and 3) as a flow path for supplying the heat medium to each of the air conditioners 2 and 3; and a heat medium discharge path 43b connected to the downstream ends of the air conditioners 2 and 3 (the downstream ends of the heat medium flow path in each of the air conditioners 2 and 3) as a flow path for discharging the heat medium from each of the air conditioners 2 and 3.

[0035] In this case, the heat medium supply path 43a and the heat medium discharge path 43b are common flow paths for the air conditioners 2 and 3, and the air conditioners 2 and 3 are connected in parallel between the heat medium supply path 43a and the heat medium discharge path 43b. The first outward path 41a and the second outward path 42a are connected to the heat medium supply path 43a so as to merge with the heat medium supply path 43a, and the first return path 41b and the second return path 42b are connected to the heat medium discharge path 43b so as to branch off from the heat medium discharge path 43b. A check valve 49 is installed in the second outward path 42a.

[0036] Because the heat medium circuit 40 is configured as described above, the first outward path 41a, the heat medium supply path 43a, the heat medium discharge path 43b, and the first return path 41b constitute a flow path that allows the heat medium to circulate between the heat medium-side heat exchanger 12 of the heat pump 11 and each of the air conditioners 2 and 3 without passing through the first heat exchanger 23a of the low-temperature side heating section 21a. In addition, the second outward path 42a, the heat medium supply path 43a, the heat medium discharge path 43b, and the second return path 42b constitute a flow path that allows the heat medium to circulate between the first heat exchanger 23a of the low-temperature side heating section 21a and each of the air conditioners 2 and 3 without passing through the heat medium-side heat exchanger 12 of the heat pump 11.

[0037] Additionally, the low-temperature side heating section 21a may be provided with a bypass path for flowing the heat medium from the second return path 42b to the second outward path 42a, bypassing the first heat exchanger 23a, and a control valve for adjusting the ratio between the flow rate of the heat medium in the bypass path and the flow rate of the heat medium in the first heat exchanger 23a.

[0038] 1 shows one heating air conditioner 2 and one cooling and heating air conditioner 3, the air conditioning system 1 may include a plurality of heating air conditioners or a plurality of cooling and heating air conditioners. In this case, the plurality of heating air conditioners or the plurality of cooling and heating air conditioners are each connected in parallel between the heat medium supply path 43a and the heat medium discharge path 43b.

[0039] Although not shown, each of the air conditioners 2 and 3 is provided with an on-off valve such as a thermal valve that opens and closes the flow path of the heat medium therein, and when the on-off valve is controlled to be open, the heat medium can flow from the heat medium supply path 43a to the heat medium discharge path 43b, and when the on-off valve is controlled to be closed, the flow of the heat medium is blocked. The on-off valve of each of the air conditioners 2 and 3 is controlled to be open when the air conditioner 2 or 3 is operating.

[0040] The heat transfer medium circuit 40 further includes a bypass path 44 connected between the first outbound path 41a and the first inbound path 41b so as to branch off from the middle of the first outbound path 41a and merge with the middle of the first inbound path 41b, a flow path switching device 45 for switching the flow path, and two electric pumps 46, 47 as a power source for circulating the heat transfer medium.

[0041] In this embodiment, the flow path switching device 45 includes a first switching valve 45a assembled at a branching portion from the heat medium discharge path 43b to the first return path 41b and the second return path 42b (a connection portion between the heat medium discharge path 43b and the first return path 41b and the second return path 42b), and a second switching valve 45b assembled at a connection portion between the first return path 41b and the bypass path 44. Note that, although the first switching valve 45a and the second switching valve 45b are depicted in FIG. 1 as devices external to the heat pump unit 10 and the combustion type heat source apparatus 20, they may also be mounted on the heat pump unit 10 or the combustion type heat source apparatus 20.

[0042] The first switching valve 45a is, for example, an electrically operated three-way valve, and by controlling its operation, it can be selectively operated in a first operating state in which the heat transfer medium discharge path 43b is opened to the first return path 41b and closed to the second return path 42b, a second operating state in which the heat transfer medium discharge path 43b is opened to the second return path 42b and closed to the first return path 41b, and a third operating state in which the heat transfer medium discharge path 43b is opened to both the first return path 41b and the second return path 42b.

[0043] In this case, the first operating state of the first switching valve 45a is, in other words, an operating state in which a flow path is formed between the heat medium-side heat exchanger 12 of the heat pump 11 and each of the air conditioners 2 and 3, allowing the heat medium to circulate without passing through the first heat exchanger 23a of the low-temperature side heating section 21a. The second operating state of the first switching valve 45a is, in other words, an operating state in which a flow path is formed between the first heat exchanger 23a of the low-temperature side heating section 21a and each of the air conditioners 2 and 3, allowing the heat medium to circulate without passing through the heat medium-side heat exchanger 12 of the heat pump 11. The third operating state of the first switching valve 45a is, in other words, an operating state in which a flow path is formed between both the heat medium-side heat exchanger 12 of the heat pump 11 and the first heat exchanger 23a of the low-temperature side heating section 21a and each of the air conditioners 2 and 3.

[0044] The second switching valve 45b is configured, for example, as an electrically operated three-way valve, and by controlling its operation, it can selectively operate between an A operating state in which the bypass path 44 is blocked from the first return path 41b and the first return path 41b upstream of the second switching valve 45b is opened to the first return path 41b downstream, and a B operating state in which the bypass path 44 is opened to the first return path 41b downstream of the second switching valve 45b and the first return path 41b upstream of the second switching valve 45b is blocked from the first return path 41b downstream.

[0045] In this case, the A-operating state of the second switching valve 45b is, in other words, an operating state in which the heat medium discharged from the heat medium-side heat exchanger 12 of the heat pump 11 can be returned to the heat medium-side heat exchanger 12 via each of the air conditioning devices 2 and 3 without passing through the bypass path 44, and the B-operating state is, in other words, an operating state in which the entire amount of the heat medium discharged from the heat medium-side heat exchanger 12 of the heat pump 11 can be returned to the heat medium-side heat exchanger 12 via the bypass path 44.

[0046] Additionally, in this embodiment, the first switching valve 45a is provided at the branch point from the heat medium discharge path 43b to the first return path 41b and the second return path 42b, but instead of the first switching valve 45a, for example, a switching valve formed by a three-way valve or the like can be provided at the junction of the first outbound path 41a and the second outbound path 42a to the heat medium supply path 43a, and operational states equivalent to the first, second, and third operational states can be realized by controlling the operation of the switching valve. Alternatively, for example, an on-off valve or a flow control valve can be installed in each of the first outbound path 41a and the second outbound path 42a, or in each of the first return path 41b and the second return path 42b, and operational states equivalent to the first, second, and third operational states can be realized by controlling the on-off valve or the flow control valve.

[0047] Furthermore, instead of the second switching valve 45b, for example, a switching valve constituted by a three-way valve or the like may be provided at the connection between the first outbound path 41a and the bypass path 44, and operation control of the switching valve may be performed to realize operation states equivalent to the above-mentioned operation state A and operation state B. Alternatively, for example, an on-off valve or a flow control valve may be installed in each of the bypass path 44 and the flow path downstream of the connection between the bypass path 44 and the first outbound path 41a, or in each of the flow path upstream of the connection between the bypass path 44 and the first return path 41b, and operation states equivalent to the above-mentioned operation state A and operation state B may be realized by controlling the opening and closing of these on-off valves or flow control valves.

[0048] The pump 46 (hereinafter sometimes referred to as the first pump 46) is a pump mounted on the heat pump unit 10 as a power source for circulating the heat medium through a flow path in the heat medium circuit 40 that passes through the heat medium-side heat exchanger 12 of the heat pump 11, and is attached to one of the first outward path 41a and the first return path 41b, for example, the first outward path 41a. Operation of the first pump 46 enables the heat medium to circulate from the heat medium-side heat exchanger 12 through the first outward path 41a, the heat medium supply path 43a, each of the air conditioners 2 and 3, the heat medium discharge path 43b, and the first return path 41b in this order, and then return to the heat medium-side heat exchanger 12.

[0049] The pump 47 (hereinafter sometimes referred to as the second pump 47) is a pump mounted on the combustion-type heat source unit 20 as a power source for circulating the heat medium through a flow path that passes through the first heat exchanger 23a of the low-temperature side heating section 21a in the heat medium circuit 40, and is attached to one of the second outward path 42a and the second return path 42b, for example, the second outward path 42a. Operation of the second pump 47 makes it possible to circulate the heat medium so that the heat medium flows from the first heat exchanger 23a through the second outward path 42a, the heat medium supply path 43a, each of the air conditioners 2 and 3, the heat medium discharge path 43b, and the second return path 42b in this order, before returning to the first heat exchanger 23a.

[0050] Temperature sensors for detecting the temperature of the heat medium are also installed in the heat medium circuit 40. In this embodiment, for example, a temperature sensor 48a for detecting the temperature of the heat medium supplied from the heat pump unit 10 to the heat medium supply path 43a, a temperature sensor 48b for detecting the temperature of the heat medium supplied from the low-temperature side heating section 21a of the combustion type heat source unit 20 to the heat medium supply path 43a, a temperature sensor 48c for detecting the temperature of the heat medium supplied to the air conditioners 2 and 3, and a temperature sensor 48d for detecting the temperature of the heat medium discharged from the air conditioners 2 and 3 are installed in the first outward path 41a, the second outward path 42a, the heat medium supply path 43a, and the heat medium discharge path 43b, respectively.

[0051] 2, the air conditioning system 1 further includes a control device 60 that controls the operation of the air conditioning system 1, and a remote control 70 that allows a user to operate the air conditioning system 1. The control device 60 is configured with one or more electronic circuit units including, for example, a processor such as a microcomputer (not shown), memory (RAM, ROM, etc.), an interface circuit, a communication circuit, etc.

[0052] For example, control device 60 may be configured as an assembly of multiple electronic circuit units that are mounted on heating air conditioner 2, cooling and heating air conditioner 3, bathroom heating device 4, heat pump unit 10, combustion heat source unit 20, and flow path switching device 45, and that communicate with each other and cooperate to control the operation of air conditioning system 1. In this case, the assembly of electronic circuit units may be configured so that one of the electronic circuit units functions as a higher-level control device that oversees the overall operation of air conditioning system 1, and the other electronic circuit units function as control devices that perform local operation control of heating air conditioner 2, cooling and heating air conditioner 3, heat pump unit 10, combustion heat source unit 20, and flow path switching device 45, respectively.

[0053] The control device 60 receives sensing signals (detection signals) from a plurality of sensors, such as the temperature sensors 34, 48a to 48d, provided in the air conditioning system 1. The control device 60 can also communicate with a remote control 70 via wired or wireless communication. Through this communication, the control device 60 can receive command information related to the operation of the heating air conditioner 2, the cooling and heating air conditioner 3, and the bathroom heating device 4 from the remote control 70, and can transmit various notification information to the remote control 70 to output.

[0054] Air conditioning system 1 may include multiple remote controls rather than one remote control 70. For example, air conditioning system 1 may include separate remote controls for heating air conditioner 2, cooling and heating air conditioner 3, and bathroom heating device 4.

[0055] The control device 60 includes, as functions realized by the implemented hardware configuration and program (software configuration), an air conditioning operation control unit 61 that executes control processing related to the operation of the air conditioners 2 and 3, and a bathroom operation control unit 62 that executes control processing related to the operation of the bathroom heating device 4.

[0056] In this case, the elements to be controlled by the air conditioning operation control unit 61 include the first pump 46 of the heat pump unit 10 and a compressor (not shown) of the refrigerant circuit 13, the low-temperature side heating unit 21a and the second pump 47 of the combustion heat source unit 20, the first switching valve 45a and the second switching valve 45b of the flow path switching device 45, and the on-off valves (not shown) that open and close the flow paths of the heat medium in each of the air conditioners 2 and 3. More specifically, the operation of the low-temperature side heating unit 21a is controlled through the operation control of the on-off valves 27 and 28a and the fuel adjustment valve 29a of the fuel supply device 24, and the operation of an ignition device (not shown).

[0057] Furthermore, the elements controlled by bathroom operation control unit 62 include high-temperature side heating unit 21b, pump 32, and on-off valve 33 of combustion-type heat source unit 20, as well as a blower fan and air path switching device (not shown) mounted on bathroom heating unit 4. More specifically, operation control of high-temperature side heating unit 21b is performed through operation control of on-off valves 27, 28b and fuel adjustment valve 29b of fuel supply unit 24, and an ignition device (not shown). Supplementally, the air conditioning operation control unit 61 not only functions as the control unit in the present invention, but also includes the function of the requested heat quantity determining unit in the present invention.

[0058] Next, the operation of the air conditioning system 1 of this embodiment will be described. First, the cooling operation of the cooling and heating air conditioner 3 will be described. When an instruction to perform cooling operation of the cooling and heating air conditioner 3 is given by the remote control 70, the control device 60 controls the air conditioning operation control unit 61 to control the first switching valve 45a of the flow path switching device 45 to a first operating state and to control the second switching valve 45b to an A-operating state. As a result, the heat medium discharge path 43b of the heat medium circuit 40 is opened to the heat medium-side heat exchanger 12 of the heat pump 11 via the first return path 41b, and the flow of the heat medium through the second return path 42b and the bypass path 44 is blocked.

[0059] In this state, the air conditioning operation control unit 61 controls the opening of an on-off valve (not shown) in the heat medium flow path of the cooling and heating air conditioner 3, and also operates the first pump 46. At the same time, the air conditioning operation control unit 61 operates the heat pump 11 so that the refrigerant is returned from the heat medium side heat exchanger 12 of the heat pump 11 to the heat medium side heat exchanger 12 via a compressor (not shown), an outdoor air side heat exchanger, and an expansion mechanism in that order. The rotation speed of the first pump 46 and the rotation speed of the compressor (not shown) of the heat pump 11 are controlled according to the temperature level of the indoor space, which is set by the remote control 70, for example.

[0060] As a result, the heat medium circulates between the heat medium-side heat exchanger 12 of the heat pump 11 and the cooling and heating air conditioner 3 through the first outward path 41a, the heat medium supply path 43a, the heat medium discharge path 43b, and the first return path 41b, and the heat medium is cooled by heat exchange with the refrigerant (heat dissipation from the heat medium to the refrigerant) in the heat medium-side heat exchanger 12. The heat medium also absorbs heat from the air in the indoor space through heat exchange with the air in the cooling and heating air conditioner 3. This cools the indoor space in which the cooling and heating air conditioner 3 is located.

[0061] Next, the heating operation of the air conditioners 2, 3 (one or both of the heating air conditioner 2 and the cooling and heating air conditioner 3) will be described. In this embodiment, the heating operation modes of the air conditioners 2, 3 include a first heating operation mode in which the heat medium is heated by the heat pump 11, a second heating operation mode in which the heat medium is heated by the low-temperature side heating section 21a of the combustion heat source unit 20, and a third heating operation mode in which the heat medium is heated by both the heat pump 11 and the low-temperature side heating section 21a. The control device 60 causes the air conditioners 2, 3 to perform the heating operation in any of the first to third heating operation modes.

[0062] In this case, which of the first to third heating operation modes the air conditioners 2 and 3 will use for heating can be determined by reflecting various conditions such as the cost of using electricity as an energy source for the heat pump 11, the cost of using fuel as an energy source for the low-temperature side heating section 21a, the user's wishes, and the load on the air conditioners 2 and 3.

[0063] For example, the control device 60 can prioritize performing the heating operation of the air conditioners 2, 3 in the first heating operation mode during a time period when the cost of electricity usage is lower than the cost of fuel usage, and can cause the air conditioners 2, 3 to perform the heating operation in the third heating operation mode as a supplementary operation when, for example, the load on the air conditioners 2, 3 becomes large. Also, the control device 60 can prioritize performing the heating operation of the air conditioners 2, 3 in the second heating operation mode during a time period when the cost of electricity usage is higher than the cost of fuel usage, and can cause the air conditioners 2, 3 to perform the heating operation in the third heating operation mode as a supplementary operation when, for example, the load on the air conditioners 2, 3 becomes large.

[0064] Furthermore, the control device 60 can also cause the air conditioners 2 and 3 to perform the heating operation in, for example, one of the first to third heating operations, whichever mode the user specifies using the remote control 70. In this way, which of the first to third heating operations the air conditioners 2 and 3 should perform the heating operation in can be determined according to various conditions.

[0065] In the first heating operation mode, the control device 60 controls the air conditioning operation control unit 61 to control the first switching valve 45a of the flow path switching device 45 to the first operating state and the second switching valve 45b to the A-operating state, as in the cooling operation mode. In this state, the air conditioning operation control unit 61 controls the opening and closing valves (not shown) of the heat medium flow paths of each of the air conditioners 2 and 3 that are the targets of heating operation, and also operates the first pump 46. The air conditioning operation control unit 61 also operates the heat pump 11 to return the refrigerant from the heat pump 11 from the heat medium-side heat exchanger 12 to the heat medium-side heat exchanger 12 via an expansion mechanism, an outdoor air-side heat exchanger, and a compressor (not shown) in this order. The rotation speed of the first pump 46 and the rotation speed of the compressor (not shown) of the heat pump 11 are controlled according to the temperature of the indoor space, for example, as set by the remote control 70.

[0066] As a result, the heat medium circulates between the heat medium-side heat exchanger 12 of the heat pump 11 and the air conditioners 2 and 3 that are in heating operation through the first outward path 41a, the heat medium supply path 43a, the heat medium discharge path 43b, and the first return path 41b, and the heat medium is heated by heat exchange with the refrigerant in the heat medium-side heat exchanger 12 (heat dissipation from the refrigerant to the heat medium). The heat medium also dissipates heat to the air in the indoor space through heat exchange with the air in the air conditioners 2 and 3 that are in heating operation. This heats the indoor space in which the air conditioners 2 and 3 that are in heating operation are located.

[0067] Furthermore, in the second heating operation mode, the control device 60 controls the first switching valve 45a of the flow path switching device 45 to the second operating state and the second switching valve 45b to the A-operating state, via the air conditioning operation control unit 61. As a result, the heat medium discharge path 43b of the heat medium circuit 40 is opened to the first heat exchanger 23a of the low-temperature side heating section 21a via the second return path 42b, and the flow of the heat medium in the first return path 41b and the bypass path 44 is blocked.

[0068] In this state, the air conditioning operation control unit 61 controls the opening of the on-off valves (not shown) in the flow paths of the heat medium in each of the air conditioners 2 and 3 that are in heating operation, and also operates the second pump 47. At the same time, the air conditioning operation control unit 61 starts the combustion operation of the first burner 22a in the low-temperature side heating unit 21a. The rotation speed of the second pump 47 and the combustion amount of the first burner 22a are controlled according to the temperature level of the indoor space, which is set by the remote control 70, for example.

[0069] As a result, the heat medium circulates between the first heat exchanger 23a of the low-temperature side heating section 21a and the air conditioners 2 and 3 that are in heating operation through the second outward path 42a, the heat medium supply path 43a, the heat medium discharge path 43b, and the second return path 42b, and the heat medium is heated in the first heat exchanger 23a by the combustion heat of the first burner 22a. The heat medium also radiates heat to the air in the indoor space through heat exchange with the air in the air conditioners 2 and 3 that are in heating operation. This heats the indoor space in which the air conditioners 2 and 3 that are in heating operation are located.

[0070] Furthermore, in the third heating operation mode, the control device 60 controls the air conditioning operation control unit 61 to set the first switching valve 45a of the flow path switching device 45 to the third operating state and the second switching valve 45b to the A operating state. As a result, the heat medium discharge path 43b of the heat medium circuit 40 is opened to the heat medium-side heat exchanger 12 of the heat pump 11 via the first return path 41b and to the first heat exchanger 23a of the low-temperature side heating unit 21a via the second return path 42b. In addition, the flow of the heat medium through the bypass path 44 is blocked.

[0071] In this state, the air conditioning operation control unit 61 controls the opening and closing of the on-off valves (not shown) in the heat medium flow paths of each of the air conditioners 2 and 3 that are in heating operation, and further operates both the first pump 46 and the second pump 47. At the same time, the air conditioning operation control unit 61 operates the heat pump 11 so that the refrigerant of the heat pump 11 is returned to the heat medium side heat exchanger 12 from the heat medium side heat exchanger 12 via an expansion mechanism, an outdoor air side heat exchanger, and a compressor (not shown) in that order, and starts the combustion operation of the first burner 22a of the low-temperature side heating unit 21a. The rotation speeds of the first pump 46 and the second pump 47, the rotation speed of the compressor (not shown) of the heat pump 11, and the combustion amount of the first burner 22a are controlled according to the temperature level of the indoor space, which is set, for example, by the remote control 70.

[0072] As a result, the heat medium circulates between the heat medium-side heat exchanger 12 of the heat pump 11 and the air conditioners 2 and 3 that are in heating operation through the first outward path 41a, the heat medium supply path 43a, the heat medium discharge path 43b, and the first return path 41b, and the heat medium is heated by heat exchange with the refrigerant (heat dissipation from the refrigerant to the heat medium) in the heat medium-side heat exchanger 12. At the same time, the heat medium circulates between the first heat exchanger 23a of the low-temperature side heating section 21a and the air conditioners 2 and 3 that are in heating operation through the second outward path 42a, the heat medium supply path 43a, the heat medium discharge path 43b, and the second return path 42b, and the heat medium is heated in the first heat exchanger 23a by the combustion heat of the first burner 22a. The heat medium then dissipates heat to the air in the indoor space through heat exchange with the air in the indoor space in the air conditioners 2 and 3 that are in heating operation. As a result, the indoor space in which the air conditioners 2 and 3 that are the targets of heating operation are located is heated.

[0073] In this case, the flow rate of the heat medium passing through the heat medium-side heat exchanger 12 of the heat pump 11 and the flow rate of the heat medium passing through the first heat exchanger 23a of the low-temperature side heating section 21a can be adjusted separately by the first pump 46 and the second pump 47. Therefore, the flow rates of the heat medium supplied from the heat pump 11 and the low-temperature side heating section 21a to the air conditioners 2 and 3 can be appropriately changed in response to changes in the heat quantities required by the air conditioners 2 and 3, etc. In this embodiment, the heating operations of the air conditioners 2 and 3 in the first to third heating operation modes are performed as described above.

[0074] In this case, in the first heating operation mode, the heat medium does not flow through the first heat exchanger 23a of the low-temperature side heating section 21a or the second return path 42b and the second outward path 42a, so that heat radiation loss and pressure loss can be reduced. Similarly, in the second heating operation mode, the heat medium does not flow through the heat medium-side heat exchanger 12 of the heat pump 11 or the first return path 41b and the first outward path 41a, so that heat radiation loss and pressure loss can be reduced.

[0075] Next, we will explain the operation when the heating operation of the air conditioners 2, 3 is shifted from the first heating operation mode to the third heating operation mode. For example, if a user operates the remote control 70 to increase the temperature of the indoor space during heating operation in the first heating operation mode, the required heat amount of the air conditioners 2, 3 to be heated (the required value of the amount of heat to be supplied per unit time to the air conditioners 2, 3 to be heated) increases, and the output of the heat pump 11 (the amount of heat of the heat medium) becomes insufficient for the required heat amount, which may cause a shift from the first heating operation mode to the third heating operation mode.

[0076] In this case, in this embodiment, the control device 60 controls the operation of the heat pump 11 and the first pump 46, and the first burner 22a and second pump 47 of the low-temperature side heating section 21a so as to transition to the third heating operation mode while maintaining the amount of heat of the heat medium by the heat pump 11 (the output of the heat pump 11) and the rotation speed of the first pump 46 (and thus the flow rate of the heat medium by the first pump 46) in the first heating operation mode immediately before the mode transition.

[0077] Specifically, the air conditioning operation control unit 61 of the control device 60 sets the required heat quantity of the air conditioners 2 and 3 that are in heating operation before and after the mode transition in accordance with whether the required temperature value of the indoor space is high or low, as set by the remote control 70. The required heat quantity is set to be larger as the required temperature value of the indoor space is higher.

[0078] In this embodiment, in the first heating operation mode, when the required heat quantity of the air conditioners 2 and 3 is equal to or less than the predetermined upper limit output of the heat pump 11, the output Qhp1 of the heat pump 11 (the amount of heat of the heat medium per unit time) and the flow rate Fhp1 of the heat medium by the first pump 46 are controlled based on the following equation (1). Qhp1=Qr1=(Bti-Bto)·Fhp1 ……(1)

[0079] Here, Qr1 is the heat quantity required by the air conditioners 2 and 3 in the first heating operation mode, Bti is the target temperature of the heat transfer medium supplied to the air conditioners 2 and 3 (e.g., 60°C), and Bto is the temperature of the heat transfer medium discharged from the air conditioners 2 and 3 (the temperature detected by the temperature sensor 48d).

[0080] Therefore, the output Qhp1 of the heat pump 11 is controlled to match the heat quantity Qr1 required by the air conditioners 2 and 3, and the flow rate Fhp1 of the heat medium by the first pump 46 is controlled to match the value obtained by dividing the heat quantity Qr1 required by the temperature difference (Bti - Bto) (in other words, so that the heat medium discharged from the air conditioners 2 and 3 can be raised in temperature from Bto to Bti by the heat pump 11). The output of the heat pump 11 is adjusted by controlling the rotation speed of a compressor (not shown) in the refrigerant circuit 13, and the flow rate of the heat medium by the first pump 46 is adjusted by controlling the rotation speed of the first pump 46.

[0081] When the heat quantity required by the air conditioners 2 and 3 exceeds the predetermined upper limit output of the heat pump 11, the required heat quantity cannot be met by the output of the heat pump 11 in the first heating operation, so the air conditioning operation control unit 61 shifts the heating operation mode from the first heating operation mode to the third heating operation mode. In this case, the air conditioning operation control unit 61 controls the output Qhp2 of the heat pump 11 after the mode shift and the flow rate Fhp2 of the heat medium by the first pump 46 so as to maintain them at the output Qhp1 and flow rate Fhp1 before the mode shift, respectively, as shown in the following equations (2a) and (2b). Qhp2=Qhp1 ……(2a) Fhp2=Fhp1 ……(2b)

[0082] Furthermore, the air conditioning operation control unit 61 controls the amount of heat Qg2 of the heat medium by the first burner 22a after the mode change and the flow rate Fg2 of the heat medium by the second pump 47 based on the following equation (3). Qg2=Qr2-Qhp2=(Bti-Bto)·Fg2 ……(3)

[0083] Here, Qr2 is the heat quantity required by the air conditioners 2 and 3 after the mode change. Therefore, the heat quantity Qg2 of the heat medium by the first burner 22a after the mode change is controlled to be a value obtained by subtracting the output Qhp2 of the heat pump 11 (= the heat quantity Qr1 required immediately before the mode change) from the heat quantity Qr2 required by the air conditioners 2 and 3 after the mode change. In addition, the flow rate Fg2 of the heat medium by the second pump 47 is controlled to match the value obtained by dividing the heat quantity Qg2 of the heat medium by the first burner 22a by the temperature difference (Bti - Bto) (in other words, so that the heat medium discharged from the air conditioners 2 and 3 and flowing through the second return path 42b to the low-temperature side heating section 21a can be heated from Bto to Bti by the combustion operation of the first burner 22a). The amount of heat Qg2 of the heat transfer medium by the first burner 22a is adjusted by controlling the amount of fuel gas supplied to the first burner 22a, and the flow rate of the heat transfer medium by the second pump 47 is adjusted by controlling the rotation speed of the second pump 47.

[0084] To give an example of specific numerical values, for example, if the heat amount required by the air conditioners 2 and 3 before the mode change is, for example, 3 kW, the heat amount required by the air conditioners 2 and 3 after the mode change is, for example, 5 kW, the target temperature of the heat medium supplied to the air conditioners 2 and 3 is, for example, 60°C, and the temperature of the heat medium discharged from the air conditioners 2 and 3 is, for example, 40°C, then the output Qhp1 of the heat pump 11 before the mode change and the flow rate Fhp1 of the heat medium by the first pump 46 are, respectively, Qhp1 = 3 kW = 43 kcal / min and Fhp1 = 2.15 liters / min = 2150 cm 3After the mode change, the output Qhp2 of the heat pump 11, the flow rate Fhp2 of the heat medium by the first pump 46, the amount of heat Qg2 of the heat medium by the first burner 22a, and the flow rate Fg2 of the heat medium by the second pump 47 are respectively Qhp2=3 kW=43 kcal / min, Fhp2=2.15 liters / min=2150 cm 3 / min, Qg2=2kW=28.67kcal / min, Fg2=1.43 liters / min=1430cm 3 / min.

[0085] In the above numerical example, the temperature of the heat transfer medium discharged from the air conditioners 2 and 3 is constant before and after the mode transition, but even if the temperature changes before and after the mode transition, the amount of heat Qg2 of the heat transfer medium by the first burner 22a after the mode transition and the flow rate Fg2 of the heat transfer medium by the second pump 47 can be calculated based on the above formula (3).

[0086] In this embodiment, when the heating operation mode transitions from the first heating operation mode to the third heating operation mode, the operation of heat pump 11, first pump 46, low-temperature side heating unit 21a, and second pump 47 is controlled as described above, so that the operating states of heat pump 11 and first pump 46 can be kept constant before and after the mode transition. This increases the stability of the heating state of the heat medium by heat pump 11, and ultimately enables the heating operation mode to transition smoothly from the first heating operation mode to the third heating operation mode so as to minimize fluctuations in the temperature supplied to the air conditioners 2 and 3.

[0087] Next, we will explain the operation of the heat pump unit 10 when anti-freeze operation is performed during the heating operation of the air conditioners 2 and 3 in the second heating operation mode. In the second heating operation mode, the heat pump 11 is not operating, and the heat pump unit 10 is installed outdoors. Therefore, when the outdoor temperature drops to low, there is a risk that the heat pump 11 (heat medium-side heat exchanger 12, etc.), the first outward path 41a, and the first return path 41b may freeze. For this reason, the heat pump unit 10 performs anti-freeze operation to prevent these components from freezing. When performing anti-freeze operation of the heat pump unit 10, the air conditioning operation control unit 61 of the control device 60 maintains the heating operation of the air conditioners 2 and 3 in the second heating operation mode. At the same time, the air conditioning operation control unit 61 controls the second switching valve 45b to switch from the A operating state to the B operating state. As a result, the first outward path 41a is opened to the first return path 41b via the bypass path 44.

[0088] In this state, the air conditioning operation control unit 61 activates the first pump 46. This causes the heat medium to circulate through the heat medium-side heat exchanger 12, the first outward path 41a, the bypass path 44, and the first return path 41b, preventing freezing in various parts of the heat pump unit 10. If the outside temperature drops to a level where freezing cannot be prevented by circulating the heat medium alone, the heat pump 11 is operated to heat the refrigerant in the refrigerant circuit 13, and the heated refrigerant is supplied to the heat medium-side heat exchanger 12, thereby heating the heat medium circulating through the heat medium-side heat exchanger 12, the first outward path 41a, the bypass path 44, and the first return path 41b.

[0089] In this case, the heat medium flowing through the heat medium-side heat exchanger 12 returns to the heat medium-side heat exchanger 12 via the first outward path 41a, the bypass path 44, and the first return path 41b, thereby preventing the low-temperature heat medium from being supplied to the air conditioning devices 2 and 3.

[0090] It should be noted that this anti-freeze operation can be performed even when the air conditioners 2 and 3 are not performing heating operation. In this case, the air conditioning operation control unit 61 does not need to change the state of the first switching valve 45a, but simply controls the second switching valve 45b to switch from operation state A to operation state B, operates the first pump 46, and operates the heat pump 11 as necessary to heat the refrigerant in the refrigerant circuit 13 and supply the heated refrigerant to the heat medium-side heat exchanger 12.

[0091] Next, we will explain the heating operation (or drying operation) of bathroom heating device 4. When remote control 70 is used to instruct bathroom heating device 4 to operate in heating operation (or drying operation), control device 60 controls the operation of bathroom heating device 4 using bathroom operation control unit 62. Specifically, bathroom operation control unit 62 opens on-off valve 33 of circulation path 31 and activates pump 32. In this state, bathroom operation control unit 62 then starts the combustion operation of second burner 22b of high-temperature side heating unit 21b. The combustion amount of second burner 22b is controlled so that the temperature of the heat medium supplied to bathroom heating device 4 (the temperature detected by temperature sensor 34) reaches a predetermined target temperature (e.g., 80°C).

[0092] As a result, the heat medium circulates via circulation path 31 between second heat exchanger 23b of high-temperature side heating section 21b and bathroom heating device 4, and is heated in second heat exchanger 23b by the combustion operation of second burner 22b, and the heated heat medium is supplied to bathroom heating device 4. Then, bathroom operation control unit 62 controls the blower fan (not shown) of bathroom heating device 4, so that warm air heated by the heat medium supplied to bathroom heating device 4 is blown into the bathroom.

[0093] In this embodiment, circulation path 31, through which the heat transfer medium for bathroom heating device 4 flows, is a flow path independent (separate) from heat transfer medium circuit 40, so the high-temperature heat transfer medium supplied to bathroom heating device 4 does not flow into heat transfer medium circuit 40. Therefore, whether heating air conditioner 2 or cooling / heating air conditioner 3 is operating in heating mode, or cooling air conditioner 3 is operating in cooling mode, bathroom heating device 4 can operate in heating mode (or drying mode) without affecting the operating status of air conditioners 2, 3.

[0094] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 3. Note that an air conditioning system 1' of this embodiment differs only in part from the air conditioning system 1 of the first embodiment, and therefore, a description of the same matters as in the first embodiment will be omitted.

[0095] In the first embodiment, the circulation path 31, which is the flow path of the heat medium for the bathroom heating device 4, is configured as a flow path independent (separate) from the heat medium circuit 40 for the air conditioners 2 and 3. However, in the air conditioning system 1' of this embodiment, for example, as shown in Figure 3, a circulation path 31' is configured to circulate the heat medium between the bathroom heating device 4 and the second heat exchanger 23b of the high-temperature side heating section 21b.

[0096] In this air conditioning system 1′, the configuration of return line 31c of circulation line 31′ differs from that of the first embodiment. Specifically, return line 31c is configured to merge with second return line 42b of heat medium circuit 40 downstream of second pump 47 from bathroom heating device 4, then branch off from second return line 42b downstream of second pump 47, and reach second heat exchanger 23b of high-temperature-side heating section 21b.

[0097] Therefore, of the second return path 42b of the heat transfer medium circuit 40, the flow path between the junction and branch point of the return path 31c on the bathroom heating device 4 side (the flow path including the second pump 47) has the function of returning the heat transfer medium from the air conditioning devices 2, 3 to the first heat exchanger 23a of the low-temperature side heating section 21a, and the function of returning the heat transfer medium from the bathroom heating device 4 to the second heat exchanger 23b of the high-temperature side heating section 21b.

[0098] Additionally, in this embodiment, second pump 47 functions as a power source for circulating the heat medium between air conditioners 2, 3 and first heat exchanger 23a of low-temperature-side heating section 21a, and also as a power source for circulating the heat medium between bathroom heating unit 4 and second heat exchanger 23b of high-temperature-side heating section 21b. Therefore, no dedicated pump is provided in circulation path 31'.

[0099] Except for the points described above, the air conditioning system 1' of this embodiment is the same as that of the first embodiment. In this air conditioning system 1', the cooling operation of the cooling and heating air conditioner 3 and the heating operation of the air conditioners 2 and 3 are performed in the same manner as in the first embodiment.

[0100] Furthermore, when bathroom heating device 4 is in heating operation (or drying operation), second burner 22b of high-temperature side heating section 21b is operated in combustion mode with on-off valve 33 of circulation path 31' kept open and second pump 47 in operation. In this case, as in the first embodiment, the combustion amount of second burner 22b is controlled so that the temperature of the heat medium supplied to bathroom heating device 4 reaches a predetermined target temperature (e.g., 80°C).

[0101] When bathroom heating device 4 is in heating operation (or drying operation), the heat transfer medium after heat dissipation in bathroom heating device 4 flows into second return line 42b of heat transfer medium circuit 40, but the high-temperature heat transfer medium supplied to bathroom heating device 4 from second heat exchanger 23b of high-temperature side heating section 21b does not flow into heat transfer medium circuit 40. Therefore, whether heating air conditioner 2 or heating and cooling air conditioner 3 is in heating operation, or heating and cooling air conditioner 3 is in cooling operation, bathroom heating device 4 can be in heating operation (or drying operation) without affecting the operating state of air conditioners 2, 3.

[0102] The present invention is not limited to the first or second embodiment described above, and other embodiments may also be employed. For example, while air conditioning systems 1, 1' are equipped with combustion-type heat source unit 20 as the second heat source, the air conditioning system of the present invention may be equipped with, for example, an electric heat source unit instead of combustion-type heat source unit 20. The air conditioning system of the present invention may also be a system that does not include a heat dissipation device such as bathroom heating device 4. In this case, high-temperature-side heating unit 21b and circulation paths 31, 31' may be omitted.

[0103] In addition, while the above embodiments have exemplified bathroom heating device 4 as a heat dissipation device of the present invention, the heat dissipation device may also be, for example, a heat exchanger that dissipates heat from a heated heat medium to the water in the bathtub. Furthermore, to prevent heat pump unit 10 from freezing, a heater may be installed in heat pump unit 10. In this case, second switching valve 45b and bypass path 44 may be omitted.

[0104] Furthermore, in each of the above-described embodiments, a first pump 46 for the flow path passing through the heat medium-side heat exchanger 12 of the heat pump 11 and a second pump 47 for the flow path passing through the first heat exchanger 23a of the low-temperature side heating section 21a are provided, but instead of these pumps 46, 47, for example, a pump may be provided in the heat medium supply path 43a or the heat medium discharge path 43b. However, when the first pump 46 and the second pump 47 are provided as in each of the above-described embodiments, even if one of the pumps 46 or 47 fails, the heat medium heated by the other pump 47 or 46, either the heat pump 11 or the low-temperature side heating section 21a, can be supplied to the air conditioners 2, 3 to perform heating operation.

[0105] Furthermore, in each of the above embodiments, combustion heat source unit 20 is equipped with first burner 22a for heating the heat medium to be supplied to air conditioners 2 and 3, and second burner 22b for heating the heat medium to be supplied to bathroom heating unit 4 (heat dissipation unit), but, for example, a common burner may be provided for each unit, and a sensible heat heat exchanger that transfers sensible heat generated by the combustion operation of the burner to the heat medium, and a latent heat heat exchanger that transfers latent heat to the heat medium, may be provided.The heat medium flow path may be configured so that the heat medium heated by the sensible heat heat exchanger can be supplied to bathroom heating unit 4 (heat dissipation unit), and so that the heat medium heated by the latent heat heat exchanger can be supplied to air conditioners 2 and 3. [Explanation of symbols]

[0106] 1,1'...air conditioning system, 2,3...air conditioning device, 4...bathroom heating device (heat dissipation device), 10...heat pump unit (first heat source), 20...combustion type heat source machine (second heat source), 21a...low temperature side heating section, 21b...high temperature side heating section, 31,31'...circulation path, 40...heat medium circuit, 41a...first forward path, 41b...first return path, 42a...second forward path, 42b...second return path, 43a...heat medium supply path, 43b...heat medium discharge path, 45...flow path switching device, 45a,45b...switching valve, 46...first pump, 47...second pump, 61...air conditioning operation control unit (required heat quantity determination unit, control unit).

Claims

1. a first heat source capable of heating or cooling a heat medium; a second heat source capable of heating the heat medium; an air conditioning device that performs heat exchange between the heat medium and the indoor space to air-condition the indoor space; a heat medium circuit that connects the first heat source and the second heat source in parallel to the air conditioning device so as to circulate the heat medium between the air conditioning device and one or both of the first heat source and the second heat source; a flow path switching device configured by first and second switching valves provided in the heat medium circuit, and capable of selectively operating in a first operating state forming a flow path for circulating the heat medium between the first heat source and the air conditioning device without passing through the second heat source, a second operating state forming a flow path for circulating the heat medium between the second heat source and the air conditioning device without passing through the first heat source, and a third operating state forming a flow path for circulating the heat medium between both the first heat source and the second heat source and the air conditioning device; a control device; and a cooling operation in which the heat medium is cooled by the first heat source while circulating between the first heat source and the air conditioning device with the flow path switching device in the first operating state; a first heating operation in which the heat medium is heated by the first heat source while circulating between the first heat source and the air conditioning device with the flow path switching device in the first operating state; a second heating operation in which the heat medium is heated by the second heat source while circulating between the second heat source and the air conditioning device with the flow path switching device in the second operating state; and a third heating operation in which the heat medium is heated by the first heat source and the second heat source while circulating between both the first heat source and the second heat source and the air conditioning device with the flow path switching device in the third operating state, the heat medium circuit includes: a first outgoing path connected to the first heat source so as to send out the heat medium from the first heat source; a first returning path connected to the first heat source so as to return the heat medium to the first heat source; a second outgoing path connected to the second heat source so as to send out the heat medium from the second heat source; a second returning path connected to the second heat source so as to return the heat medium to the second heat source; a heat medium supply path connected to the first outgoing path and the second outgoing path so as to join the first outgoing path and the second outgoing path, and connected to the air conditioner so as to supply the heat medium to the air conditioner; a heat medium discharge path connected to the air conditioner so as to discharge the heat medium from the air conditioner, and branching into the first returning path and the second returning path; and a bypass path that bypasses the first outgoing path and the first returning path, The control device controls the first switching valve and the second switching valve of the flow path switching device to selectively execute (i) a first return operation state in which the heat medium discharged from the first heat source is returned from the air conditioner to the first heat source without passing through the bypass path, and (ii) a second return operation state in which the heat medium discharged from the first heat source is returned to the first heat source via the bypass path.

2. 2. The air conditioning system according to claim 1, an air conditioning system characterized in that the heat medium circuit includes a first pump provided in a flow path of the heat medium circuit that passes only the first heat source of the first heat source and the second heat source, and a second pump provided in a flow path of the heat medium circuit that passes only the second heat source of the first heat source and the second heat source.

3. 3. The air conditioning system according to claim 2, the control device executes a process of determining a required heat amount of the air conditioning device in accordance with a required temperature state of the indoor space, a process of controlling the heat amounts of the first heat source and the second heat source, and a process of controlling the operation of the first pump and the second pump, The air conditioning system is characterized in that, when switching from the first heating operation to the third heating operation due to an increase in the heat quantity required by the air conditioning device during execution of the first heating operation, the control device is configured to control the heat quantity of the second heat source and the rotation speed of the second pump so as to achieve the increased heat quantity required by the air conditioning device while maintaining the heat quantity of the first heat source and the rotation speed of the first pump at the same levels as during the first heating operation.

4. In the air conditioning system according to any one of claims 1 to 3, the second heat source includes, as a heating unit for heating the heat medium, a low-temperature side heating unit for heating the heat medium to a low-temperature side temperature and a high-temperature side heating unit for heating the heat medium to a high-temperature side temperature, the heat medium circuit includes a flow path passing through the low-temperature side heating unit as a flow path passing through the second heat source, the high-temperature-side heating section is connected to a heat dissipation device via a circulation path so as to circulate the heat medium between the high-temperature-side heating section and the heat dissipation device, which dissipates heat from the heat medium heated to the high-temperature-side temperature; The circulation path is configured to prevent the heat medium supplied from the high-temperature side heating portion to the heat dissipation device from flowing into the heat medium circuit.

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