GB2548309A

GB2548309A - Air conditioning and hot water supply combined system

Info

Publication number: GB2548309A
Application number: GB1710957.0A
Authority: GB
Inventors: Kawagoe Tomokazu; Morimoto Osamu
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-03-16
Filing date: 2015-03-16
Publication date: 2017-09-13
Anticipated expiration: 2035-03-16
Also published as: JP6289734B2; JPWO2016147305A1; GB201710957D0; GB2548309B; WO2016147305A1

Abstract

Provided is an air conditioning and hot water supply combined system (A) in which system COP is improved by suppressing the frequency of the occurrence of high-pressure suppression control by a bypass of a heat source unit (100), in a case where, in a heating operation, a heating load and a hot water supply load are small. The air conditioning and hot water supply combined system (A) is provided with the following: an air conditioning-side refrigerant circuit (20) in which formed is a refrigeration cycle where a load-side unit (200) equipped with a load-side heat exchanger (212) and a load-side restriction device (211) is connected, by refrigerant piping, to a heat source unit (100) equipped with a heat source-side compressor (111) for compressing air conditioning-use refrigerant and heat source-side heat exchangers (113a, 113b); a hot water supply-side refrigerant circuit (30) in which formed is a refrigeration cycle where a hot water supply unit compressor (321) for compressing hot water supply-use refrigerant, a water heat exchanger (322) for exchanging heat between hot water supply-use water and hot water supply-use refrigerant, a hot water supply-side refrigerant circuit restriction device (323), and a refrigerant-to-refrigerant heat exchanger (312) for exchanging heat between the air conditioning-use refrigerant and the hot water supply-use refrigerant are connected by refrigerant piping; and a hot water supply unit (300) equipped with the refrigerant-to-refrigerant heat exchanger (312) and an air conditioning-side refrigerant circuit restriction device (311) which are connected in parallel to the load-side unit (200) in the air conditioning-side refrigerant circuit (20). In a state where the heat operation cycle is operating, the hot water supply unit (300) causes the driving frequency of the hot water supply unit compressor (321) to increase if the pressure on the high-pressure side of the air conditioning-side refrigerant circuit (20) has exceeded a high-pressure threshold, or if the condensation temperature in the air conditioning-side refrigerant circuit (20) has exceeded a condensation temperature threshold.

Description

DESCRIPTION Title of Invention AIR-CONDITIONING AND HOT WATER SUPPLY COMPOSITE SYSTEM Technical Field [0001]

The present invention relates to an air-conditioning and hot water supply composite system including a heat pump cycle and configured to provide an air-conditioning load and a hot water supply load at the same time.

Background Art [0002]

An air-conditioning and hot water supply composite system is conventionally known that includes an air-conditioning refrigerant system including a compressor, an outdoor heat exchanger, an expansion device, a plurality of indoor heat exchangers, and an accumulator, and a hot water supply refrigerant system including a compressor, a water heat exchanger, an expansion device, and a refrigerant-to-refrigerant heat exchanger. The hot water supply refrigerant system is cascade-connected to a part of condensers of the air-conditioning refrigerant system, to provide a room heating load and a hot water supply load at the same time (see, for example, Patent Literature 1). Citation List Patent Literature [0003]

Patent Literature 1: International Publication No. 09/098751 (first page, Fig. 1, and others)

Summary of Invention Technical Problem [0004]

In the air-conditioning and hot water supply composite system disclosed in Patent Literature 1, the high-side pressure of the refrigerant in a lower stage (air-conditioning side refrigerant circuit) sharply increases when the hot water supply load is small because of a small or non-existent room heating load. Although thereafter the sharp increase of the high-side pressure is suppressed by protective control, for example, performed through a refrigerant bypass, the coefficient of performance (COP) of the system may be degraded because the operation through the bypass is inefficient. The mentioned phenomenon frequently takes place in a transitional phase between the activation and the stabilization of the system.

[0005]

The present invention has been accomplished to solve the foregoing problem, and an object of the present invention is to provide an air-conditioning and hot water supply composite system configured to lower the high-side pressure of the refrigerant in the lower stage and to improve the system COP without performing the protective control through the refrigerant bypass, when the room heating load and the hot water supply load are small.

Solution to Problem [0006]

An air-conditioning and hot water supply composite system according to an embodiment of the present invention includes an air-conditioning side refrigerant circuit in which a load-side unit including a load-side heat exchanger and a load-side expansion device is connected via a refrigerant pipe to a heat source unit including a heat source-side compressor that compresses air-conditioning refrigerant and a heat source-side heat exchanger, the air-conditioning side refrigerant circuit constituting a refrigeration cycle; a hot water supply side refrigerant circuit in which a hot water supply unit compressor that compresses hot water supply refrigerant, a water heat exchanger that exchanges heat between water used for hot water supply and the hot water supply refrigerant, a hot water supply side refrigerant circuit expansion device, and a refrigerant-to-refrigerant heat exchanger that exchanges heat between the air-conditioning refrigerant and the hot water supply refrigerant are connected to each other via a refrigerant pipe to constitute a refrigeration cycle; and a hot water supply unit including the refrigerant-to-refrigerant heat exchanger connected in parallel to the load-side unit in the air-conditioning side refrigerant circuit, and the air-conditioning side refrigerant circuit expansion device. The hot water supply unit is configured to increase a drive frequency of the hot water supply unit compressor, when a pressure on a high-pressure side of the air-conditioning side refrigerant circuit exceeds a high-pressure threshold or when a condensing temperature of the air-conditioning side refrigerant circuit exceeds a condensing temperature threshold, in a room heating operation cycle.

Advantageous Effects of Invention [0007]

With the air-conditioning and hot water supply composite system according to an embodiment of the present invention, increasing the load to be borne by the air-conditioning side refrigerant circuit (lower stage) suppresses the increase of the high-side pressure in the heat source-side refrigerant circuit, and also reduces the frequency at which the protective control is performed through the refrigerant bypass, thereby contributing to improving the system COP.

Brief Description of Drawings [0008] [Fig. 1] Fig. 1 is a circuit diagram showing an exemplary refrigerant circuit configuration of an air-conditioning and hot water supply composite system according to Embodiment 1.

[Fig. 2] Fig. 2 is a flowchart showing a process of protective control against excessive increase in high-side pressure, performed on the basis of self-decision of a hot water supply unit.

[Fig. 3] Fig. 3 is a flowchart showing a control process of instruction transmission from a heat source unit to the hot water supply unit.

[Fig. 4] Fig. 4 is a flowchart showing a control process for the hot water supply unit based on the instruction from the heat source unit.

[Fig. 5] Fig. 5 is a flowchart showing a control process of instruction transmission from the heat source unit to the hot water supply unit, according to Embodiment 3. Description of Embodiments [0009]

Embodiment 1

Hereafter, Embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a circuit diagram showing an exemplary refrigerant circuit configuration of an air-conditioning and hot water supply composite system A according to Embodiment 1 of the present invention. The air-conditioning and hot water supply composite system A is a system into which two refrigeration cycles (heat pump cycles), namely an air-conditioning side refrigerant circuit 20 and a hot water supply side refrigerant circuit 30, are integrated. In Fig. 1 and other drawings below, the dimensional relationship among the components may differ from the actual one.

[0010]

The air-conditioning and hot water supply composite system A according to Embodiment 1 is applicable for use in a building, a condominium, a hotel, or other facilities, and configured to supply a room heating load and a hot water supply load at the same time, utilizing a refrigeration cycle through which refrigerant (air-conditioning refrigerant, hot water supply refrigerant) circulates. The air-conditioning and hot water supply composite system A at least includes a heat source unit 100 (outdoor unit), a load-side unit 200 (indoor unit), and a hot water supply unit 300.

[0011] (Configuration of Air-Conditioning side refrigerant circuit 20)

The air-conditioning side refrigerant circuit 20 includes the heat source unit 100, the load-side unit 200, and a part of the hot water supply unit 300. The load-side unit 200 and the hot water supply unit 300 are connected in parallel to the heat source unit 100.

[0012]

The heat source unit 100 and the load-side unit 200 are connected to each other sequentially via a gas main pipe 1, a gas branch pipe 3a, a liquid branch pipe 4a, and a liquid main pipe 2, that each serve as a refrigerant pipe. The heat source unit 100 and the hot water supply unit 300 are connected to each other sequentially via the gas main pipe 1, a gas branch pipe 3b, a liquid branch pipe 4b, and the liquid main pipe 2, that each serve as the refrigerant pipe.

[0013] (Heat Source Unit 100)

The heat source unit 100 includes a heat source-side compressor 111, a flow switching valve 112, heat source-side heat exchangers 113a and 113b, and an accumulator 114, that are connected in series. In addition, though not illustrated, the heat source unit 100 also includes a non-i I lustrated air-sending device such as a fan for supplying air to the heat source-side heat exchangers 113a and 113b, located in the vicinity thereof. The heat source unit 100 supplies heating energy or cooling energy to the load-side unit 200 and the hot water supply unit 300.

[0014]

The heat source unit 100 includes a bypass valve 115a, a bypass valve 115b, and a bypass valve 115c for the purpose of protective control. The bypass valve 115a is located between the heat source-side heat exchanger 113b and the liquid main pipe 2. The bypass valve 115b is provided in a pipe connecting between a pipe provided from the bypass valve 115a to the heat source-side heat exchanger 113b and a pipe provided from the discharge port (high side) of the heat source-side compressor 111 to flow switching valve 112. The bypass valve 115c is located between the discharge port (high side) of the heat source-side compressor 111 and the suction side of the accumulator 114. The bypass valve 115b and the bypass valve 115c are intended to allow high-pressure gas refrigerant to circumvent to the low-pressure side.

Accordingly, the positions to set the high side of the bypass valve 115b and the bypass valve 115c may be varied as desired, provided that the high-pressure gas flows through those positions.

[0015]

The heat source-side compressor 111 sucks the air-conditioning refrigerant of a low-temperature and low-pressure state, and compresses the air-conditioning refrigerant thereby turning it into high-temperature and high-pressure state. The type of the heat source-side compressor 111 is not specifically limited provided that the sucked air-conditioning refrigerant can be compressed into high-pressure state. For example, the heat source-side compressor 111 may be of a reciprocating type, a rotary type, or a screw type. It is preferable that the heat source-side compressor 111 includes an inverter for variably controlling the rotation speed.

[0016]

The flow switching valve 112 switches the flow direction of the air-conditioning refrigerant according to a required operation mode. The flow switching valve 112 is connected to the discharge side of the heat source-side compressor 111, to switch the flow direction of the high-pressure refrigerant discharged from the heat source-side compressor 111.

The heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b serve as radiator (condenser) in a room cooling cycle, and as evaporator in a room heating cycle, and exchange heat between the air supplied from the non-illustrated air-sending device and the air-conditioning refrigerant to thereby condense and liquefy, or evaporate and gasify the air-conditioning refrigerant. The accumulator 114 is located on the suction side of the heat source-side compressor 111, to store a surplus amount of the air-conditioning refrigerant. The accumulator 114 may simply be a container capable of storing the surplus air-conditioning refrigerant. The gas main pipe 1 is connected to the accumulator 114, the heat source-side compressor 111, the heat source-side heat exchanger 113a, and the heat source-side heat exchanger 113b, via the flow switching valve 112. The liquid main pipe 2 is connected to the heat source-side heat exchanger 113a and the bypass valve 115a.

[0017]

The heat source unit 100 includes a heat source unit controller 131. The heat source unit controller 131 is, for example, constituted of a microcomputer, and serves to control the capacity control amount of the heat source-side compressor 111, or the heat exchanger capacity control amount (based on both heat exchange area and air volume) of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b, according to measured values acquired from a pressure sensor 116 or a temperature sensor 117. The heat source unit controller 131 also controls the opening and closing of the bypass valves 115, and the opening and closing of the flow switching valve 112 according to the operation mode.

Further, the heat source unit controller 131 transmits, if need be, internal information of the heat source unit 100 (e.g., measured values of pressure sensor 116 and temperature sensor 117) to a load-side unit controller 231 of the load-side unit 200 and a hot water supply unit controller 331 of the hot water supply unit 300, through communication devices 31 and 32. In addition, the heat source unit controller 131 can perform remote control of, for example, the air volume of the air-sending devices attached to the heat source-side heat exchangers 113 and a load-side heat exchanger 212, and the opening degree of a load-side expansion device 211 (expansion valve).

[0018] (Load-Side Unit 200)

The load-side unit 200 receives the heating energy or cooling energy from the heat source unit 100, to assume the room heating load or room cooling load. The load-side unit 200 includes the load-side expansion device 211 and the load-side heat exchanger 212 (indoor heat exchanger), that are connected in series. Although a single load-side unit 200 is illustrated in Fig. 1, the number of load-side units is not specifically limited. In addition, it is preferable that the load-side unit 200 includes a non-illustrated air-sending device such as a fan for supplying air to the load-side heat exchanger 212, located in the vicinity thereof.

[0019]

The load-side expansion device 211 has a function of a reducing valve or an expansion valve, to depressurize and expand the air-conditioning refrigerant. The load-side expansion device 211 may be constituted of a precise flow control device, for example, an electronic expansion valve the opening degree of which is variably controllable, or an inexpensive refrigerant flow control device such as capillary tubes.

The load-side heat exchanger 212 serves as radiator (condenser) in the room heating cycle, and as evaporator in the room cooling cycle. The load-side heat exchanger 212 exchanges heat between the air supplied from the non-illustrated airsending device provided close thereto and the air-conditioning refrigerant, to thereby condense and liquefy, or evaporate and gasify the air-conditioning refrigerant.

[0020]

The load-side unit 200 includes the load-side unit controller 231. The load-side unit 200 controls, for example, the opening degree of the load-side expansion device 211 and the air volume of the non-illustrated air-sending device attached to the load-side heat exchanger 212, according to a value from a non-illustrated pressure sensor, a value from a temperature sensor 216, and values according to the information from the heat source unit 100 acquired through the communication device 31. The load-side unit 200 is also configured to perform a controlling operation according to a signal indicating an operation command, upon receipt thereof from the heat source unit 100 through the communication device 31.

[0021] (Hot Water Supply Unit 300)

The hot water supply unit 300 supplies the heating energy or cooling energy received from the heat source unit 100 to the hot water supply side refrigerant circuit 30 through a refrigerant-to-refrigerant heat exchanger 312. The air-conditioning side of the hot water supply unit 300 includes the air-conditioning refrigerant side of the refrigerant-to-refrigerant heat exchanger 312 and the air-conditioning side refrigerant circuit expansion device 311, and constitutes a part of an air-conditioning refrigerant system. In other words, the air-conditioning side refrigerant circuit 20 and the hot water supply side refrigerant circuit 30 are connected to each other via the refrigerant-to-refrigerant heat exchanger 312.

[0022]

The refrigerant-to-refrigerant heat exchanger 312 serves to exchange heat between the hot water supply refrigerant circulating in the hot water supply side refrigerant circuit and the air-conditioning refrigerant circulating in the air-conditioning side refrigerant circuit.

The air-conditioning side refrigerant circuit expansion device 311 has a function of a reducing valve or an expansion valve like the load-side expansion device 211, to depressurize and expand the air-conditioning refrigerant. The air-conditioning side refrigerant circuit expansion device 311 may be constituted of a precise flow control device, for example, an electronic expansion valve the opening degree of which is variably controllable, or an inexpensive refrigerant flow control device such as capillary tubes.

[0023]

The hot water supply unit 300 includes the hot water supply unit controller 331. The hot water supply unit controller 331 is configured to control, for example, the air-conditioning side refrigerant circuit expansion device 311 and the air volume of the airsending device, according to the values from the pressure sensor 317 or temperature sensor 316, and the information from the heat source unit 100 received through the communication device 32. In addition, the hot water supply unit controller 331 is configured to perform a controlling operation according to a signal indicating an operation command, upon receipt thereof from the heat source unit 100 through the communication device 32.

[0024]

As described above, the air-conditioning side refrigerant circuit 20 includes the heat source-side compressor 111, the flow switching valve 112, the load-side heat exchanger 212, the load-side expansion device 211, and the heat source-side heat exchangers 113, that are sequentially connected in series, and the refrigerant-to-refrigerant heat exchanger 312 connected in parallel to the load-side heat exchanger 212, to allow the air-conditioning refrigerant to circulate through the mentioned components.

[0025] (Operation of Air-Conditioning and Hot Water Supply Composite System A)

The operation modes performed by the air-conditioning and hot water supply composite system A include a room cooling operation mode and a room heating operation mode. In the room cooling operation mode, the load-side unit 200 being driven to realize the room cooling operation cycle performs the room cooling operation. In the room heating operation mode, the load-side unit 200 being driven to realize the room heating operation cycle performs the room heating operation, and the hot water supply unit performs the hot water supplying operation. In the room heating operation mode, the load-side unit 200 and the hot water supply unit 300 may be operated at the same time, or individually operated under a restriction in priority order or other factors.

[0026] (Room Cooling Operation Mode)

The air-conditioning refrigerant, in a low-pressure gas state, is sucked into the heat source-side compressor 111. The air-conditioning refrigerant turned into high-temperature high-pressure gas in the heat source-side compressor 111 is discharged therefrom, and flows into the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b through the flow switching valve 112. The air-conditioning refrigerant in the high-temperature and high-pressure gas state, which has entered the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b, transfers heat through heat exchange with the air supplied from the air-sending device attached to the heat source-side heat exchangers 113, thereby turning into high-pressure liquid refrigerant, and flows out of the heat source unit 100 through the liquid main pipe 2.

[0027]

The high-pressure liquid state air-conditioning refrigerant that has flowed out through the liquid main pipe 2 flows into the load-side unit 200 through the liquid branch pipe 4a. The air-conditioning refrigerant that has entered the load-side unit 200 is depressurized in the load-side expansion device 211 thereby turning into low-pressure liquid and gas two-phase refrigerant, or low-pressure liquid refrigerant, and flows into the load-side heat exchanger 212.

[0028]

The low-pressure air-conditioning refrigerant that has entered the load-side heat exchanger 212 is evaporated in the load-side heat exchanger 212 thereby turning into low-pressure gas refrigerant, and flows out of the load-side heat exchanger 212. The low-pressure gas state air-conditioning refrigerant that has flowed out of the load-side heat exchanger 212 flows through the gas branch pipe 3a, and flows into the heat source unit 100 through the gas main pipe 1. The low-pressure gas state air-conditioning refrigerant that has entered the heat source unit 100 flows through the flow switching valve 112 and the accumulator 114, and is again sucked into the heat source-side compressor 111.

[0029] (Room Heating Operation Mode)

The low-pressure gas state air-conditioning refrigerant is sucked into the heat source-side compressor 111. The air-conditioning refrigerant turned into high-temperature high-pressure gas in the heat source-side compressor 111 is discharged therefrom, and flows out of the heat source unit 100 through the flow switching valve 112 and the gas main pipe 1. The high-pressure gas refrigerant that has flowed out through the gas main pipe 1 branches to flow into the gas branch pipe 3a and the gas branch pipe 3b.

[0030]

The high-pressure gas refrigerant that has entered the gas branch pipe 3a flows into the load-side unit 200. The refrigerant that has entered the load-side unit 200 flows into the load-side heat exchanger 212 to be condensed (transfer heat) through heat exchange with the air, and flows out in the form of high-pressure liquid refrigerant. After flowing out, the high-pressure liquid state air-conditioning refrigerant is depressurized in the load-side expansion device 211 thereby turning into low-pressure liquid and gas two-phase refrigerant, or low-pressure liquid refrigerant, and flows out of the load-side unit 200 through the liquid branch pipe 4a.

The high-pressure gas refrigerant that has entered the gas branch pipe 3b flows into the hot water supply unit 300. The refrigerant that has entered the hot water supply unit 300 flows into the refrigerant-to-refrigerant heat exchanger 312 to be condensed (transfer heat) through heat exchange with the hot water supply refrigerant, and flows out in the form of high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out of the refrigerant-to-refrigerant heat exchanger 312 is depressurized in the air-conditioning side refrigerant circuit expansion device 311 thereby turning into low-pressure liquid and gas two-phase refrigerant, or low-pressure liquid refrigerant, and flows out of the hot water supply unit 300 through the liquid branch pipe 4b.

[0031]

The flows of the low-pressure air-conditioning refrigerant from the liquid branch pipe 4a and the liquid branch pipe 4b are merged, and the merged refrigerant flow enters the heat source unit 100 through the liquid main pipe 2. The low-pressure air-conditioning refrigerant that has entered the heat source unit 100 branches to flow into the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b. The low-pressure refrigerant that has entered the heat source-side heat exchangers 113a and 113b exchanges heat with the air supplied from the air-sending device, thereby turning into low-pressure gas refrigerant, and flows out of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b. The refrigerant that has flowed out of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b is again sucked into the heat source-side compressor 111 through the flow switching valve 112 and the accumulator 114.

[0032] (Configuration of Hot Water Supply side refrigerant circuit 30)

The hot water supply unit 300 includes a section constituting a part of the air-conditioning side refrigerant circuit 20, the hot water supply side refrigerant circuit 30, and a section constituting a part of a water circuit including a water heat exchanger 322 for exchanging heat with the hot water supply refrigerant. The hot water supply side refrigerant circuit 30 supplies the heating energy or cooling energy received from the air-conditioning refrigerant through the refrigerant-to-refrigerant heat exchanger 312 to the water circuit through the water heat exchanger 322. The hot water supply side refrigerant circuit 30 includes a hot water supply unit compressor 321, the water heat exchanger 322, a hot water supply side refrigerant circuit expansion device 323, and the hot water supply refrigerant side of the refrigerant-to-refrigerant heat exchanger 312.

[0033]

Thus, the hot water supply unit 300 includes two types of refrigerant systems. A section of the hot water supply unit 300 on the side of the air-conditioning side refrigerant circuit 20 includes the air-conditioning side refrigerant circuit expansion device 311 provided between the liquid branch pipe 4b and the gas branch pipe 3b, and a section of the refrigerant-to-refrigerant heat exchanger 312 on the side of the air-conditioning side refrigerant circuit 20, that are connected to each other. The other section of the hot water supply unit 300 on the side of the hot water supply side refrigerant circuit 30 includes the hot water supply unit compressor 321, the water heat exchanger 322, the hot water supply side refrigerant circuit expansion device 323, and the hot water supply side refrigerant circuit of the refrigerant-to-refrigerant heat exchanger 312, that are connected to each other via the refrigerant pipe.

The refrigerant pipe includes gas pipes (discharge gas pipe 5, suction gas pipe 8) and liquid pipes (water heat exchanger outlet liquid pipe 6, expansion valve outlet liquid pipe 7) sequentially connected to each other.

[0034]

The hot water supply unit compressor 321 sucks the hot water supply refrigerant of a low-pressure gas state and compresses the hot water supply refrigerant thereby turning it into high-temperature and high-pressure gas state. The hot water supply unit compressor 321 may include an inverter for variably controlling the rotation speed.

The type of the hot water supply unit compressor 321 is not specifically limited provided that the sucked hot water supply refrigerant can be compressed into high-pressure gas. For example, the hot water supply unit compressor 321 may be of a reciprocating type, a rotary type, or a screw type.

[0035]

The water heat exchanger 322 serves to exchange heat between a heat medium circulating in the water circuit 40 (fluid such as water or antifreeze) and the hot water supply refrigerant circulating in the hot water supply side refrigerant circuit 30. Accordingly, the hot water supply side refrigerant circuit and the water circuit are connected to each other via the water heat exchanger 322 and water pipes 11 and 12. The hot water supply side refrigerant circuit expansion device 323 has a function of a reducing valve or an expansion valve, to depressurize and expand the hot water supply refrigerant. The hot water supply side refrigerant circuit expansion device 323 may be constituted of a precise flow control device, for example, an electronic expansion valve the opening degree of which is variably controllable, or an inexpensive refrigerant flow control device such as capillary tubes.

The refrigerant-to-refrigerant heat exchanger 312 exchanges heat, as mentioned above, between the hot water supply refrigerant circulating in the hot water supply side refrigerant circuit and the air-conditioning refrigerant circulating in the air-conditioning side refrigerant circuit. Referring to Fig. 1, the water pipe 11 serves as a return water pipe, and the water pipe 12 serves as a hot water delivery pipe. Accordingly, the water is made flow in an opposite direction to the hot water supply refrigerant to attain highest heat exchange efficiency. However, the water may be made to flow reversely by using the water pipe 11 as the hot water delivery pipe and the water pipe 12 as the return water pipe, depending on the situation or purpose.

[0036] (Operation of Hot Water Supply side refrigerant circuit 30)

First, the hot water supply refrigerant turned into the high-temperature and high-pressure gas state in the hot water supply unit compressor 321 is discharged therefrom and flows into the water heat exchanger 322 through the discharge gas pipe 5. In the water heat exchanger 322, the hot water supply refrigerant that has entered transfers heat to thereby heat the water flowing in through the water pipe 11, and the hot water flows out through the water pipe 12. The hot water supply refrigerant that has flowed out of the water heat exchanger 322 flows into the hot water supply side refrigerant circuit expansion device 323 through the water heat exchanger outlet liquid pipe 6, to be expanded to a level below the temperature at the outlet of the refrigerant-to-refrigerant heat exchanger 312 in the air-conditioning side refrigerant circuit 20. The expanded hot water supply refrigerant flows into the refrigerant-to-refrigerant heat exchanger 312 through the expansion valve outlet liquid pipe 7, to receive heat from the air-conditioning refrigerant flowing in the air-conditioning side refrigerant circuit 20, thereby being evaporated. The hot water supply refrigerant thus turned into low-pressure gas flows out of the refrigerant-to-refrigerant heat exchanger 312 and returns to the hot water supply unit compressor 321 through the suction gas pipe 8.

[0037] (Configuration of Water Circuit)

The water circuit includes a non-illustrated pump, a non-illustrated hot water tank, and a section of the water heat exchanger 322 on the side of the water circuit 40, that are connected via a pipe. Thus, the water circuit 40 serves to allow the water heated or cooled in the water heat exchanger 322 to circulate. The water pipe 11 and the water pipe 12 included in the water circuit may be constituted of a copper pipe, a stainless steel pipe, a steel pipe, a PVC-based pipe or a pipe of other suitable material. Although the term "water circuit 40" is herein employed, for example, an antifreeze may be made to circulate in the circuit, in place of water.

[0038]

Although not illustrated in Fig. 1, the air-conditioning and hot water supply composite system A may include a sensor that detects the discharge pressure of the air-conditioning refrigerant, a sensor that detects the suction pressure of the air-conditioning refrigerant, a sensor that detects the discharge temperature of the air-conditioning refrigerant, a sensor that detects the suction temperature of the air-conditioning refrigerant, a sensor that detects the temperature of the air-conditioning refrigerant flowing into and out of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b, a sensor that detects the temperature of outdoor air introduced into the heat source unit 100, a sensor that detects the temperature of the air-conditioning refrigerant flowing into and out of the load-side heat exchanger 212, and a sensor that detects the temperature of the water stored in the hot water tank connected to the water circuit 40. The information detected by the cited sensors is transmitted to the heat source unit controller 131, the load-side unit controller 231, and the hot water supply unit controller 331, to be utilized for controlling each of the actuators.

[0039] (Operation of Air-Conditioning and Hot Water Supply Composite System A in Room Heating Operation Mode)

First, the control process in the room heating operation mode will be described.

The heat source unit controller 131 changes the operation frequency of the heat source-side compressor 111, which is one of control commands, to match the condensing temperature of the air-conditioning side refrigerant circuit 20 with a target value preset as desired. The heat source unit controller 131 also changes the heat exchange capacity of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b, which is another control command, to match the evaporating temperature of the air-conditioning side refrigerant circuit 20 with a target value preset as desired. For example, the heat source unit controller 131 changes the heat exchange area of the heat source-side heat exchanger 113a and the heat source-side heat exchanger 113b, and the air volume from the air-sending device. Here, the control commands are determined according to measurement information acquired from the heat source unit 100 (e.g., values from pressure sensor 116 and temperature sensor 117).

[0040]

On the part of the hot water supply side refrigerant circuit 30, the water temperature at the inlet or outlet of the water heat exchanger 322 and the water temperature set by the hot water supply unit controller 331 are compared. When the difference in water temperature is large, a drive frequency BU_F of the hot water supply unit compressor 321 is increased. When the difference in water temperature is small, in other words when the hot water supply load is small, the drive frequency BU_F of the hot water supply unit compressor 321 is reduced.

[0041] (Conventional Protective Control against Excessive Increase in High-Side Pressure)

The description given below is based on the assumption that, for example, the heat source unit controller 131 and the hot water supply unit controller 331 perform the control independently from each other. When the hot water supply load is extremely small in the room heating operation mode, the drive frequency BU_F of the hot water supply unit compressor 321 in the hot water supply side refrigerant circuit 30 is reduced, and reaches a lower limit BU_Fmin of the capacity control range of the hot water supply unit compressor 321.

[0042]

Setting thus the drive frequency of the hot water supply unit compressor 321 to the lower limit BU_Fmin of the capacity control range in the air-conditioning side refrigerant circuit 20 reduces the load of the hot water supply unit 300 and increases the high-side pressure of the air-conditioning side refrigerant circuit 20, until reaching a bypass valve activation threshold Pbyp, which is a reference value that can be preset as desired. Then the heat source unit 100 performs a protective control against excessive increase in high-side pressure, utilizing the bypass valves 115a to 115c provided in the heat source unit 100, to bring the high-side pressure of the air-conditioning side refrigerant circuit 20 within an operation pressure range.

In the air-conditioning side refrigerant circuit 20 shown in Fig. 1, the protection against excessive increase in high-side pressure can be performed by two methods.

One is switching the bypass valve 115c to an open state from a closed state and releasing the high-pressure gas refrigerant to the low-pressure side, thereby reducing the high-side pressure. The other is switching the bypass valve 115a to the closed state from the open state and switching the bypass valve 115b to the open state from the closed state, to transfer the heat of the air-conditioning refrigerant to outside by utilizing the heat source-side heat exchanger 113b as condenser, thus reducing the high-side pressure.

[0043]

Although both of the mentioned methods serve to reduce the high-side pressure to a level within the operation range, on the other hand the efficiency of the system as a heat pump is degraded. In particular, by the latter method (utilizing the heat source-side heat exchanger 113b as condenser) the heating energy received by the air-conditioning refrigerant in the heat source-side heat exchanger 113a is returned to outside from the heat source-side heat exchanger 113b, and therefore the heat is unable to be effectively utilized and the efficiency is significantly degraded. For example, the coefficient of performance (COP) drops to a range between 1 and 2, which is no better than that of an electric heater.

[0044] (Protective Control against Excessive Increase in High-Side Pressure According to Embodiment 1)

To suppress the degradation of the COP during the protective control against excessive increase in high-side pressure, Embodiment 1 intends to increase the load on the hot water supply unit side, to thereby reduce the frequency at which the protective control is performed through the bypass valve and improve the COP. The detail of such a control will be described hereunder. Although control methods may differ in each control process, the purpose is to protect the heat source unit from the excessive increase in high-side pressure by increasing the load of the hot water supply unit 300.

[0045]

Fig. 2 is a flowchart showing a process of the protective control against excessive increase in high-side pressure, performed on the basis of self-decision of the hot water supply unit 300. Immediately after the hot water supply unit 300 is activated, the protective control is also started (step S101).

The hot water supply unit 300 acquires information of a condensing temperature Ts of the heat source unit 100 at a time period preset as desired (e.g., every several minutes), from the heat source unit 100 through the communication device 32. The hot water supply unit 300 decides whether the information of the condensing temperature Ts is higher than a condensing temperature threshold Tb preset as desired in the hot water supply unit 300 (step S102).

When the condition of step S102 is satisfied (Yes at S102), the operation proceeds to the next step, where it is decided whether the current drive frequency BU_Fnow of the hot water supply unit compressor 321 is lower than a maximum value (permissible value) BU_Fmax of the drive frequency of the hot water supply unit compressor 321 (step S103).

When the condition of step S103 is satisfied (Yes at S103), the hot water supply unit 300 increases the drive frequency of the hot water supply unit compressor 321 (step S104). More specifically, the current drive frequency BU_Fnow of the hot water supply unit compressor 321 is increased by an amount dF, thereby setting a new frequency BU_Fnew.

When the condition is not satisfied at step S102 or step S103 (No at S102 or S103), the control operation is repeated in a loop from step S102. After step S104 is completed, it is decided whether the hot water supply unit 300 is in operation, and in the affirmative case (Yes at S105) the control operation is repeated in a loop (step S105).

In the case where the hot water supply unit is no longer in operation (No at S105), the control operation is finished (step S106).

[0046]

Through the mentioned control process, the load to be borne by the air-conditioning side refrigerant circuit 20 is increased by controlling the hot water supply unit 300, to suppress the increase in high-side pressure in the heat source-side refrigerant circuit, even though the high-side pressure of the air-conditioning side refrigerant circuit 20 increases. For example, even when the heat source-side compressor 111 is operating at a minimum drive frequency and hence the pressure is unable to be reduced any further by controlling the heat source-side compressor 111 in the air-conditioning side refrigerant circuit 20, the pressure increase on the high-pressure can be suppressed by increasing the load of the air-conditioning side refrigerant circuit 20. In the heat source unit 100, accordingly, the frequency at which the protective control against excessive increase in high-side pressure is performed through the bypass valves 115a to 115c can be reduced, and therefore the COP of the air-conditioning and hot water supply composite system A can be improved.

[0047]

Embodiment 2

While the protective control against excessive increase in high-side pressure is performed by the hot water supply unit 300 alone in Embodiment 1, the heat source unit 100 and the hot water supply unit 300 collaborate with each other in the control operation in Embodiment 2.

Fig. 3 is a flowchart showing a control process of instruction transmission from the heat source unit 100 to the hot water supply unit 300.

Immediately after the hot water supply unit 300 is activated while the heat source unit 100 is in operation, the protective control is started (step S211). Then the heat source unit 100 decides whether a high-side pressure sensor value Pd of the pressure sensor 116 provided on the high side of the air-conditioning side refrigerant circuit 20 is higher than a high-pressure threshold Pb preset as desired (step S212). When the condition of step S212 is satisfied (Yes at S212), the heat source unit 100 transmits a drive frequency speed-up signal (hereinafter, Fup signal) for the hot water supply unit compressor 321, to the hot water supply unit 300 through the communication device 32 (step S213). When the condition of step S212 is not satisfied, the control operation is repeated in a loop. In the case where the hot water supply unit 300 is in operation after step S213 is completed (Yes at S214) the control operation is repeated in a loop from step S212 (step S214). In the case where the hot water supply unit 300 is no longer in operation, the control operation is finished (step S215).

[0048]

Fig. 4 is a flowchart showing a control process for the hot water supply unit 300 based on the instruction from the heat source unit 100.

In the hot water supply unit 300, the protective control is started immediately after the hot water supply unit 300 is activated (step S221). The hot water supply unit 300 then decides whether the Fup signal has been received from the heat source unit 100 through the communication device 32 (step S222). In the case where the hot water supply unit has received the Fup signal (Yes at S222), it is decided whether the drive frequency BU_Fnow of the hot water supply unit compressor 321 is lower than the maximum drive frequency BU_Fmax of the hot water supply unit compressor 321 (step S223). When the condition of step S223 is satisfied (Yes at S223), the drive frequency of the hot water supply unit compressor 321 is increased (step S224). More specifically, the current drive frequency BU_Fnow of the hot water supply unit compressor 321 is increased by an amount dF, thereby setting a new frequency BU_Fnew. When the condition is not satisfied at step S222 or step S223, the control operation is repeated in a loop from step S222. After step S224 is completed, it is decided whether the hot water supply unit 300 is in operation (step S225). In the case where the hot water supply unit 300 is in operation (Yes at S225) the control operation is repeated in a loop from step S222, and in the case where the hot water supply unit is no longer in operation (No at S225), the control operation is finished (step S226).

[0049]

Thus, the load to be borne by the air-conditioning side refrigerant circuit 20 is increased by controlling the hot water supply unit 300, to suppress the increase in high-side pressure in the heat source-side refrigerant circuit, even though the high-side pressure of the air-conditioning side refrigerant circuit 20 increases. In addition, in the heat source unit 100 the frequency at which the protective control against excessive increase in high-side pressure is performed through the bypass valves 115a to 115c can be reduced, and therefore the COP of the air-conditioning and hot water supply composite system A can be improved.

[0050]

The foregoing control process improves, as in Embodiment 1, the COP of the air-conditioning and hot water supply composite system A, while performing the protection against excessive increase in high-side pressure.

Here, the control process shown in Fig. 2 and the control process shown in Fig. 3 and Fig. 4 may both be performed at the same time, or either thereof may be selectively performed. In the control process of Embodiment 1 shown in Fig. 2, however, the control period depends on the period at which the hot water supply unit 300 receives the information of the condensing temperature Ts from the heat source unit 100. Accordingly, the control of the hot water supply unit 300 may fail to effectively follow up a sharp increase in high-side pressure in the heat source unit 100. In contrast, in the control process according to Embodiment 2 the drive frequency of the hot water supply unit compressor 321 is increased when the Fup signal is received from the heat source unit 100, and therefore the control operation can effectively follow up a sharp increase in high-side pressure. Accordingly, the control methods may be selectively adopted, for example, such that the control process shown in Fig. 2 is utilized in a periodical control performed at a predetermined time interval, and the control process shown in Fig. 3 and Fig. 4 is performed as a backup protective control in the case where the high-side pressure has sharply increased in the heat source unit 100.

[0051]

Embodiment 3

In Embodiment 3, the setting of thresholds used for the control will be described, with respect to the case where the conventional protective control against excessive increase in high-side pressure, the control process of Embodiment 1, and the control process of Embodiment 2 are adopted in combination.

It is preferable to set the thresholds used for the control (condensing temperature threshold Tb of air-conditioning side refrigerant circuit 20, high-pressure threshold Pb of air-conditioning side refrigerant circuit 20), so as to satisfy such a relationship as "condensing temperature control target Tm < condensing temperature threshold Tb < saturation temperature TPb converted from high-pressure threshold Pb < saturation temperature TPbyp converted from bypass valve activation threshold Pbyp."

Normally, the control process shown in Fig. 2 is employed for the periodical control, utilizing the condensing temperature threshold Tb, which is lower than the saturation temperature TPb converted from the high-pressure threshold Pb. In the case where the high-side pressure has sharply increased, the control is performed utilizing the high-pressure threshold Pb, and in case that even the high-pressure threshold Pb is exceeded the control is performed utilizing the bypass valves 115.

[0052]

Fig. 5 is a flowchart showing a control process of instruction transmission from the heat source unit to the hot water supply unit, according to Embodiment 3.

Immediately after the hot water supply unit 300 is activated while the heat source unit 100 is in operation, the protective control is started (step S311). Then the heat source unit 100 decides whether the high-side pressure sensor value Pd of the pressure sensor 116 provided on the high side of the air-conditioning side refrigerant circuit 20 is higher than the high-pressure threshold Pb preset as desired (step S312). When the condition of step S312 is satisfied (Yes at S312), the heat source unit 100 transmits the drive frequency speed-up signal (hereinafter, Fup signal) for the hot water supply unit compressor 321, to the hot water supply unit 300 through the communication device 32 (step S313). When the condition of step S312 is not satisfied, the control operation is repeated in a loop. After step S313 is completed, the heat source unit 100 again decides whether the high-side pressure sensor value Pd is higher than the bypass valve activation threshold Pbyp preset as desired (step S314). In the case where the value Pd has not dropped and is higher than the value Pbyp (Yes at S314), the heat source unit 100 opens the bypass valves 115 (step S315), and then repeats the control operation from step S312 in a loop. When the value Pd is lower than the value Pbyp (No at S314), the heat source unit 100 closes the bypass valves 115 if they are open, and keeps the bypass valves 115 as they are if they are closed (step S316). Then the heat source unit 100 confirms the operation status of the hot water supply unit 300 (step S317). In the case where the hot water supply unit 300 is in operation (Yes at S317) the control operation is repeated in a loop from step S312 (step S317). In the case where the hot water supply unit 300 is no longer in operation, the control operation is finished (step S318).

[0053]

Performing the control operation on the basis of the thresholds set as above reduces the frequency at which the protective control against excessive increase in high-side pressure is performed through the bypass valves 115 in a transitional phase of the operation of the hot water supply unit 300, to thereby improve the COP of the air-conditioning and hot water supply composite system A.

[0054]

Hereunder, refrigerants applicable to the air-conditioning side refrigerant circuit 20 and the hot water supply side refrigerant circuit 30 will be described. The refrigerant applicable to the refrigeration cycle in the air-conditioning side refrigerant circuit 20 and the hot water supply side refrigerant circuit 30 include, for example, non-azeotropic refrigerant mixtures, near-azeotropic refrigerant mixtures, and single refrigerants.

Examples of the non-azeotropic refrigerant mixture include R407C (R32/R125/R134a), which is a hydrofluorocarbon (HFC) refrigerant. The non-azeotropic refrigerant mixture is a mixture of refrigerants different in boiling point, and therefore has a characteristic that the composition ratio differs between liquid-phase refrigerant and gas-phase refrigerant. Examples of the near-azeotropic refrigerant mixture include R410A (R32/R125) and R404A (R125/R143a/R134a), which are HFC refrigerants. The near-azeotropic refrigerant mixture has a characteristic that a working pressure approximately 60% higher than that of R22 can be obtained, in addition to the characteristic similar to that of the non-azeotropic refrigerant mixture.

[0055]

Examples of the single refrigerant include R22, which is a hydrochlorofluorocarbon (HCFC) refrigerant, and R134a, which is a FIFC refrigerant.

The single refrigerant is easy to handle, because of not being a mixture. Alternatively, carbon dioxide, which is a natural refrigerant, propane, isobutane, ammonium or similar substance may be employed. Flere, R22 represents chlorodifluoromethane, R32 represents difluoromethane, R125 represents pentafluoromethane, R134a represents 1, 1,1,2-tetrafluoromethane, and R143a represents 1,1, 1-trifluoroethane. Accordingly, it is preferable to select the refrigerant according to the condition and purpose of use of the air-conditioning side refrigerant circuit 20 and the hot water supply side refrigerant circuit 30.

[0056]

Since the air-conditioning side refrigerant circuit 20 and the hot water supply side refrigerant circuit 30 each include the refrigerant circuit independent from each other as described above, the same refrigerant, or different refrigerants may be employed for circulation in each of the refrigerant circuits. In the case where a refrigerant having a low critical temperature is employed as the hot water supply refrigerant, the hot water supply refrigerant may turn into a supercritical state during heat transfer in the water heat exchanger 322, when hot water of a high temperature is being supplied.

Flowever, when the refrigerant in a heat transfer phase is in the supercritical state, in general, the COP largely fluctuates owing to variations of the radiator pressure or the temperature at the outlet of the radiator, and therefore a highly precise control is required to perform the operation to achieve a high COP.

On the other hand, generally the refrigerant having a low critical temperature provides a higher saturation pressure at the same temperature and hence the pipe and the compressor have to have a thicker wall to withstand the higher pressure, which leads to an increase in cost.

[0057]

Further, from the viewpoint that the recommended temperature of the water stored in the non-illustrated hot water tank is stipulated as equal to or higher than 62 degrees Celsius, to suppress multiplication of Legionella bacteria or other germs, it is assumed that the target temperature of the hot water supply is at least 62 degrees Celsius, or higher. On the basis of the above, it is preferable to employ a refrigerant having a critical temperature of at least equal to, or higher than, 62 degrees Celsius, as the hot water supply refrigerant. This is because employing such a refrigerant as the hot water supply refrigerant for the hot water supply refrigerant system enables a higher COP to be achieved, at a lower cost and more stably.

[0058]

Although the surplus refrigerant is stored in a receptacle (accumulator 114) in the air-conditioning side refrigerant circuit 20 in foregoing Embodiments, the surplus refrigerant may instead be stored in the heat exchanger that serves as radiator in the refrigeration cycle, in which case the accumulator 114 may be omitted.

Further, although a single load-side unit 200 is connected to the system in Fig. 1, the number of load-side units is not specifically limited, and one or any desired number of load-side units 200 may be connected to the system. In the case where a plurality of load-side units 200 are installed, the load-side units 200 may all have the same capacity, or may each have a different capacity from a larger one to a smaller one. Reference Signs List [0059] 1: gas main pipe, 2: liquid main pipe, 3a: gas branch pipe, 3b: gas branch pipe, 4a: liquid branch pipe, 4b: liquid branch pipe, 5: discharge gas pipe, 6: water heat exchanger outlet liquid pipe, 7: expansion valve outlet liquid pipe, 8: suction gas pipe, 11: water pipe, 12: water pipe, 20: air-conditioning side refrigerant circuit, 30: hot water supply side refrigerant circuit, 31: communication device, 32: communication device, 40: water circuit, 100: heat source unit, 111: heat source-side compressor, 112: flow switching valve, 113: heat source-side heat exchanger, 113a: heat source-side heat exchanger, 113b: heat source-side heat exchanger, 114: accumulator, 115: bypass valve, 115a: bypass valve, 115b: bypass valve, 115c: bypass valve, 116: pressure sensor, 117: temperature sensor, 131: heat source unit controller, 200: load-side unit, 211: load-side expansion device, 212: load-side heat exchanger, 216: temperature sensor, 231: load-side unit controller, 300: hot water supply unit, 311: air-conditioning side refrigerant circuit expansion device, 312: refrigerant-to-refrigerant heat exchanger, 316: temperature sensor, 317: pressure sensor, 321: hot water supply unit compressor, 322: water heat exchanger, 323: hot water supply side refrigerant circuit expansion device, 331: hot water supply unit controller, A: air-conditioning and hot water supply composite system, BU_F: drive frequency, BU_Fmax: maximum drive frequency, BU_Fmin: lower limit (of drive frequency), BU_Fnew: new frequency, BU_Fnow: drive frequency, Pb: high-pressure threshold, Pbyp: bypass valve activation threshold, Pd: high-side pressure sensor value, TPb: value converted to saturation temperature from high-pressure threshold Pb, TPbyp: value converted to saturation temperature from bypass valve activation threshold Pbyp, Tb: condensing temperature threshold, Tm: condensing temperature control target, Ts: condensing temperature, dF: frequency.

Claims

CLAIMS [Claim 1] An air-conditioning and hot water supply composite system comprising: an air-conditioning side refrigerant circuit in which a load-side unit including a load-side heat exchanger and a load-side expansion device is connected via a refrigerant pipe to a heat source unit including a heat source-side compressor configured to compress air-conditioning refrigerant and a heat source-side heat exchanger, the air-conditioning side refrigerant circuit constituting a refrigeration cycle; a hot water supply side refrigerant circuit in which a hot water supply unit compressor configured to compress hot water supply refrigerant, a water heat exchanger configured to exchange heat between water used for hot water supply and the hot water supply refrigerant, a hot water supply side refrigerant circuit expansion device, and a refrigerant-to-refrigerant heat exchanger configured to exchange heat between the air-conditioning refrigerant and the hot water supply refrigerant are connected to each other via a refrigerant pipe to constitute a refrigeration cycle; and a hot water supply unit including the refrigerant-to-refrigerant heat exchanger connected in parallel to the load-side unit in the air-conditioning side refrigerant circuit, and an air-conditioning side refrigerant circuit expansion device, wherein a drive frequency of the hot water supply unit compressor is increased, when a pressure on a high-pressure side of the air-conditioning side refrigerant circuit exceeds a high-pressure threshold or when a condensing temperature of the air-conditioning side refrigerant circuit exceeds a condensing temperature threshold, in a room heating operation cycle state. [Claim 2] The air-conditioning and hot water supply composite system of claim 1, wherein the heat source unit further includes: a bypass pipe connecting between the high-pressure side and a low-pressure side of the air-conditioning side refrigerant circuit in the room heating operation cycle; and a bypass valve provided in the bypass pipe, and the heat source unit opens the bypass valve when the pressure on the high-pressure side of the air-conditioning side refrigerant circuit exceeds a bypass valve activation threshold. [Claim 3] The air-conditioning and hot water supply composite system of claim 2, wherein the condensing temperature threshold is set to a value higher than a condensing temperature control target of the air-conditioning side refrigerant circuit, and the high-pressure threshold is set to a value lower than the bypass valve activation threshold, and higher than a pressure of the air-conditioning refrigerant converted from the condensing temperature threshold assumed as saturation temperature. [Claim 4] The air-conditioning and hot water supply composite system of any one of claims 1 to 3, wherein the heat source unit further includes a heat source unit controller configured to control the heat source-side compressor, the hot water supply unit further includes a hot water supply unit controller configured to control the hot water supply unit compressor and the hot water supply side refrigerant circuit expansion device, and the heat source unit controller is configured to receive measurement information of the pressure on the high-pressure side in the air-conditioning side refrigerant circuit, and transmit a high-pressure signal for increasing the drive frequency of the hot water supply unit compressor to the hot water supply unit controller, when the pressure on the high-pressure side exceeds the high-pressure threshold.