JP5893151B2 - Air conditioning and hot water supply complex system - Google Patents

Description

  The present invention relates to an air conditioning and hot water supply combined system capable of performing air conditioning and hot water supply using a heat pump cycle.

  An air-conditioning and hot-water supply complex system has been proposed in which heat is transferred from a heat source such as air or water using a heat pump cycle (refrigeration cycle) and supplied to a plurality of indoor units (indoor units) and hot water heaters (hot water supply units). Yes. (For example, refer to Patent Document 1). In this system, a branch unit is connected to the heat source unit. In addition, at least one indoor unit and at least one hot water supply unit are connected to the branch unit. Thereby, air conditioning and hot water supply can be performed simultaneously with one heat source.

WO2009 / 098751 (first page, FIG. 1 etc.)

  In the air conditioning and hot water supply combined system described in Patent Document 1 described above, for example, at a time when the heating load is high, at least one indoor unit is heated, and when at least one hot water supply unit is stopped, the system is stopped. The throttle device in the hot water supply unit is closed to prevent the refrigerant from passing through.

  At this time, for example, if the valve constituting the throttle device is not tight, the refrigerant may flow through the refrigerant-water heat exchanger inside the hot water supply unit. At this time, if the temperature of the refrigerant passing through the refrigerant-water heat exchanger is equal to or lower than the freezing temperature of water, water freezes and expands in the refrigerant-water heat exchanger, and the refrigerant-water heat exchanger is There was a risk of damage.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air-conditioning and hot water supply combined system capable of preventing freezing in a refrigerant-water heat exchanger in a hot water supply unit.

An air conditioning and hot water supply combined system according to the present invention includes at least one heat source unit having a compressor and a heat source side heat exchanger, at least one indoor unit having an indoor side heat exchanger and an indoor side expansion device, At least one hot water supply unit having a refrigerant-water heat exchanger and a hot water supply side expansion device, an indoor unit that heats the heat exchange target, and / or a room that supplies gaseous refrigerant to the hot water supply unit and cools the heat exchange target A refrigerant circuit in which a gas-liquid separator for supplying a liquid refrigerant to the unit and / or the hot water supply unit and a branch unit having a refrigerant flow path control device for controlling the passage of the refrigerant to the indoor unit and the hot water supply unit are connected by piping. And when it is determined that water in the water-side flow path in the refrigerant-water heat exchanger may freeze while the hot water supply unit is stopped, the refrigerant-side heat flow in the refrigerant-water heat exchanger That the pressure, the refrigerant - are those comprising a pressure pipe connected via a refrigerant-side flow path and the hot water supply-side throttle device of the water heat exchanger, a control processing unit for performing control to reduce the pressure difference.

  According to the combined air conditioning and hot water supply system according to the present invention, when the control processing device determines that water in the water-side flow path in the refrigerant-water heat exchanger may freeze, the refrigerant of the refrigerant-water heat exchanger Since the pressure in the side flow path is increased, water freezing in the refrigerant-water heat exchanger can be prevented.

It is a figure which shows an example of a structure of the air-conditioning / hot-water supply complex system 000 which concerns on Embodiment 1 of this invention. It is a figure which shows the flow of the refrigerant | coolant of air_conditionaing | cooling operation mode. It is a figure which shows the flow of the refrigerant | coolant of heating operation mode. It is a figure which shows the flow of the refrigerant | coolant of a cooling main operation mode. It is a figure which shows the flow of the refrigerant | coolant of heating main operation mode. It is a figure which shows the procedure of the freeze prevention process which concerns on Embodiment 1 of this invention. It is a figure which shows the procedure of the freeze prevention process which concerns on Embodiment 2 of this invention. It is a figure which shows the procedure of the freeze prevention process which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, the configuration of the air-conditioning and hot water supply complex system described in the embodiment is an example, and is not limited to such a configuration. In addition, when there is no need to particularly distinguish or specify a device, device, or the like with a suffix added to the reference numeral, the suffix may be omitted.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of a configuration of an air conditioning and hot water supply complex system 000 according to Embodiment 1 of the present invention. The configuration of the system will be described with reference to FIG. The air conditioning and hot water supply complex system 000 according to the present embodiment is installed in, for example, a building, a condominium, a hotel, and the like, configures a refrigerant circuit by connecting devices with piping, and uses an air pump load (refrigeration cycle) to load air conditioning. Heat (hot and cold) can be supplied simultaneously to the hot water supply load.

[System configuration]
The combined air conditioning and hot water supply system 000 of the present embodiment includes at least a heat source unit (outdoor unit) 110, a branch unit (relay unit) 210, an indoor unit (indoor unit) 310, and a hot water supply unit 410. Among these, the indoor unit 310 serving as a load unit and the hot water supply unit 410 are connected to the heat source unit 110 in parallel via the branch unit 210. And the flow of a refrigerant | coolant is switched in the branch unit 210 installed between the heat source unit 110, the indoor unit 310, and the hot water supply unit 410, etc., and the function of the hot water or cold water supply in the indoor unit 310 and the hot water supply unit 410 To demonstrate. Here, FIG. 1 shows an example in which one indoor unit 310 and one hot water supply unit 410 are connected to each branch unit 210, but the number of connections is not limited to this.

  Further, the air conditioning and hot water supply complex system 000 connects the heat source unit 110 and the branch unit 210 with a high-pressure main pipe 001 and a low-pressure main pipe 002 that are refrigerant pipes so that the refrigerant flows. Further, the branch unit 210 and the indoor unit 310 are connected by gas branch pipes 003a and 003b which are refrigerant pipes. The branch unit 210 and the hot water supply unit 410 are connected by liquid branch pipes 004a and 004b that are refrigerant pipes.

  Here, the refrigerant used for the air conditioning and hot water supply complex system 000 will be described. Examples of the refrigerant that can be used in the refrigeration cycle of the air conditioning and hot water supply complex system 000 include a non-azeotropic refrigerant mixture, a pseudo-azeotropic refrigerant mixture, and a single refrigerant. There are various types of non-azeotropic refrigerants such as R407C (R32 / R125 / R134a) which is an HFC (hydrofluorocarbon) refrigerant. Therefore, it is good to use the refrigerant | coolant according to the use and objective of the air-conditioning / hot-water supply complex system 000.

  Here, since the non-azeotropic refrigerant mixture is a mixture of refrigerants having different boiling points, it has a characteristic that the composition ratio of the liquid phase refrigerant and the gas phase refrigerant is different. The pseudo azeotropic refrigerant mixture includes R410A (R32 / R125) and R404A (R125 / R143a / R134a) which are HFC refrigerants. The pseudo azeotrope refrigerant has the same characteristics as the non-azeotrope refrigerant and has an operating pressure of about 1.6 times that of R22. The single refrigerant includes R22, which is an HCFC (hydrochlorofluorocarbon) refrigerant, R134a, which is an HFC refrigerant, and the like. Since the single refrigerant is not a mixture, it has a characteristic that it is easy to handle. In addition, natural refrigerants such as carbon dioxide, propane, isobutane, and ammonia can be used. Here, R22 represents chlorodifluoromethane, R32 represents difluoromethane, R125 represents pentafluoromethane, R134a represents 1,1,1,2-tetrafluoromethane, and R143a represents 1,1,1-trifluoroethane. ing.

[Heat source unit 110]
The heat source unit 110 has a function of sending a refrigerant to the indoor unit 310 and the hot water supply unit 410 via the branch unit 210 and supplying hot and cold heat to the load. The heat source unit 110 according to the present embodiment includes a compressor 111, a flow path switching valve 112, a heat source side heat exchanger 113, and an accumulator (liquid reservoir container) 115, which are connected in series as shown in FIG. It is composed.

  The compressor 111 compresses the sucked refrigerant and discharges it in a high temperature / high pressure state. Here, the type of the compressor is not particularly limited. For example, various types of compressors such as reciprocating, rotary, scroll, and screw can be used as the compressor 111. The compressor 111 may be of a type that can be variably controlled by an inverter.

  The heat source side heat exchanger 113 functions as a radiator (condenser) or an evaporator. And heat exchange between the air used as the heat exchange object of a refrigerant | coolant and a refrigerant | coolant is performed, and a refrigerant | coolant is liquefied or evaporated gas. Here, when performing an air-conditioning mixed operation in which hot and cold supply is performed simultaneously, the heat source side heat exchanger 113 may be used as a radiator. At this time, adjustment is made so that only a part of the gaseous refrigerant (gas refrigerant) from the compressor 111 is condensed into a refrigerant in a two-phase region state of a gas refrigerant and a liquid refrigerant (liquid refrigerant). In the present embodiment, in the heat source side heat exchanger 113, heat is exchanged between the air from the blower 114 and the refrigerant. However, for example, heat is exchanged between water, brine, and the refrigerant. Also good. The blower 114 configured by a fan or the like supplies air to be heat exchanged with the refrigerant to the heat source side heat exchanger 113. The accumulator 115 is a container that is disposed on the suction side of the compressor 111 and stores excess refrigerant.

  The check valve group 116 flows in a direction in which the refrigerant flowing through the high pressure main pipe 001 flows out of the heat source unit 110 and into the branch unit 210, and the refrigerant flowing through the low pressure main pipe 002 flows out of the branch unit 210 and flows into the heat source unit 110. The flow of the refrigerant is adjusted so as to flow in the direction of flowing into the tank.

  The discharge pressure sensor 117H detects the discharge pressure of the refrigerant. The suction pressure sensor 117L detects the suction pressure of the refrigerant. The discharge temperature sensor 118H detects the discharge temperature of the refrigerant. The suction temperature sensor 118L detects the suction temperature of the refrigerant. The heat source heat exchanger temperature sensor 119a detects the temperature of the refrigerant flowing into and out of the heat source side heat exchanger 113. The outside air temperature sensor 119b detects the temperature of outside air taken into the heat source unit 110. Based on the temperature, pressure, and the like related to the detection of these various sensors, the heat source control processing device 120 controls each actuator.

[Branch unit 210]
The branch unit 210 adjusts the flow of the refrigerant between the load unit (the indoor unit 310 and the hot water supply unit 410) and the heat source unit 110. Then, the indoor heat exchanger 311 of the indoor unit 310 and the refrigerant-water heat exchanger 411 of the hot water supply unit 410 function as a radiator or an evaporator, respectively. The branch unit 210 has at least a gas-liquid separator 211, an electromagnetic valve 213a and an electromagnetic valve 213b, a liquid refrigerant throttle device 212, a bypass throttle device 214, and a branch pressure sensor 215 for detecting intermediate pressure.

  The electromagnetic valve 213a serving as the refrigerant flow control device is connected to the low-pressure main pipe 002, the gas branch pipe 003a, and the gas-liquid separator 211, and flows into and out of the indoor unit 310 based on instructions from the branch control processing device 220. The refrigerant flow path is switched to control the passage of the refrigerant. In addition, the solenoid valve 213b serving as the hot water supply unit flow path switching device is connected to the low pressure main pipe 002, the gas branch pipe 003a, and the gas-liquid separator 211, and is connected to the hot water supply unit 410 based on instructions from the branch control processing device 220. The flow path of the refrigerant flowing in and out is switched to control the passage of the refrigerant. Here, the number of electromagnetic valves 213 is not particularly limited, and the number of electromagnetic valves may be determined as necessary. In FIG. 1, two two-way solenoid valves are combined, but a three-way valve or the like may be combined.

  The gas-liquid separator 211 separates the refrigerant flowing from the high-pressure main pipe 001 into a gas refrigerant and a liquid refrigerant. The gas refrigerant flows to the solenoid valve 213 (213a, 213b) side. Further, the liquid refrigerant related to the separation of the gas-liquid separator 211 flows to the liquid refrigerant expansion device 212 side. The liquid refrigerant throttling device 212 decompresses and expands the liquid refrigerant flowing from the gas-liquid separator 211. Further, the bypass expansion device 214 adjusts the pressure and the amount of refrigerant flowing out of the indoor unit 310 and the hot water supply unit 410 and flowing into the low-pressure main pipe 002, for example. Here, the liquid refrigerant throttling device 212 and the bypass throttling device 214 are flow rate control means that can change the opening degree by precise control using, for example, an electronic expansion valve, and inexpensive refrigerant flow rate control means such as capillaries. Configure.

  The branch pressure sensor 215 is a sensor that detects an intermediate pressure. Here, in the branching unit 210, three pressure zones, that is, the pressure of the refrigerant flowing from the heat source unit 110 (high pressure), the pressure of the refrigerant flowing into the heat source unit 110 (low pressure), and the intermediate pressure between the high pressure and the low pressure, Have. The intermediate pressure can be changed by changing the opening degree of the liquid refrigerant throttle device 212 and the bypass throttle device 214. When the intermediate pressure changes, the ratio of the refrigerant flow rate flowing to the heating (hot water supply) side and the cooling (cooling) side changes, and the capacity ratio of heating (hot water supply) and cooling (cooling) changes. The branch control processing device 220 controls the opening degrees of the liquid refrigerant throttle device 212 and the bypass throttle device 214 based on the pressure related to the detection by the branch pressure sensor 215.

[Indoor unit 310]
The indoor unit 310 has a function of extracting hot or cold heat from the refrigerant sent from the heat source unit 110 and supplying it to the air conditioning load. The indoor unit 310 of the present embodiment includes an indoor unit expansion device 312 and an indoor heat exchanger 311 and is configured to be connected in series as shown in FIG. Here, although not particularly shown in FIG. 1, the indoor unit 310 may be provided with a blower such as a fan for supplying air to the indoor heat exchanger 311 in the vicinity of the indoor heat exchanger 311.

  The indoor heat exchanger 311 functions as a radiator (condenser) during heating, and functions as an evaporator during cooling. Then, heat exchange between the air in the air-conditioning target space and the refrigerant is performed, and the refrigerant is condensed into liquefied or evaporated gas. The indoor unit throttle device 312 is constituted by, for example, a pressure reducing valve (expansion valve) or the like, and expands the refrigerant by reducing the pressure. As the pressure reducing valve, for example, a flow rate control unit capable of changing the opening degree by precise control using an electronic expansion valve or the like, an inexpensive refrigerant flow rate control unit such as a capillary tube, or the like may be used.

  An indoor unit gas pipe temperature detection sensor 313G and an indoor unit liquid pipe temperature detection sensor 313L are installed in the front and rear pipes through which the refrigerant flows into and out of the indoor heat exchanger 311. The indoor air temperature sensor 314 detects the temperature of at least one of the air that the indoor heat exchanger 311 sucks or blows out. Based on the temperature related to the detection of these temperature sensors, the indoor control processing device 320 controls the opening degree of the indoor unit expansion device 312 to adjust the refrigerant flow rate.

[Hot water supply unit 410]
The hot water supply unit 410 has a function of extracting hot or cold heat from the refrigerant sent from the heat source unit 110 and supplying it to the hot water supply load. The hot water supply unit 410 of the present embodiment includes a hot water supply unit expansion device 412 and a refrigerant-water heat exchanger 411, and is configured to be connected in series as shown in FIG.

  The refrigerant-water heat exchanger 411 functions as a radiator (condenser) or an evaporator. Then, heat exchange is performed between the refrigerant and the water passing through the water pipe 010, and the refrigerant is condensed or liquefied. The hot water supply unit throttle device 412 is constituted by, for example, a pressure reducing valve (expansion valve) or the like, and decompresses the refrigerant to expand it. The hot water supply unit throttling device 412 may be composed of flow rate control means, refrigerant flow rate control means, and the like, similar to the indoor unit throttling device 312.

  A hot water supply unit gas pipe temperature detection sensor 413G and a hot water supply unit liquid pipe temperature detection sensor 413L are installed on the front and rear pipes through which the refrigerant flows into and out of the refrigerant-water heat exchanger 411. In addition, an inlet water temperature detection sensor 414I and an outlet water temperature detection sensor 414O are installed in the front and rear pipes through which water flows into and out of the refrigerant-water heat exchanger 411. Based on the temperature related to the detection of these temperature sensors, the hot water supply control processing device 420 controls the opening degree of the hot water supply unit expansion device 412 to adjust the refrigerant flow rate. In addition, a sensor or the like for detecting the temperature of water stored in a hot water storage tank (not shown) may be provided.

  The water pipe 010 is a pipe that configures a water circuit by connecting a pump, a hot water storage tank, a refrigerant-water heat exchanger 411, and the like (not shown). In the water circuit, water heated or cooled by heat exchange in the refrigerant-water heat exchanger 411 circulates. The water pipe 010 may be constituted by, for example, a copper pipe, a stainless pipe, a steel pipe, a vinyl chloride pipe, or the like. Here, in the present embodiment, water is circulated in the water circuit. However, for example, antifreeze or the like may be circulated.

  The heat source unit 110, the branch unit 210, the indoor unit 310, and the hot water supply unit 410 have a heat source control processing device 120, a branch control processing device 220, an indoor control processing device 320, and a hot water supply control processing device 420, respectively. Here, each unit is provided with a control processing device, but may be integrated into one or more units.

  The heat source control processing device 120 included in the heat source unit 110 performs, for example, a process of controlling the refrigerant pressure state and the refrigerant temperature state in the air conditioning and hot water supply complex system 000. Specifically, for example, processing relating to control of the driving frequency of the compressor 111, control of the fan rotation speed of the blower 114, switching of the flow path switching valve 112, and the like are performed.

  Further, the branch control processing device 220 included in the branch unit 210 performs processes such as opening control of the liquid refrigerant throttle device 212 and bypass throttle device 214, and opening / closing control of the electromagnetic valves 213 (electromagnetic valves 213a and 213b). Do.

  The indoor control processing device 320 included in the indoor unit 310 performs processing for controlling each device in order to air-condition the air-conditioning target space. For example, when the indoor unit 310 is cooled, a process of controlling the degree of superheating of the refrigerant is performed, and when performing heating, a process of controlling the degree of supercooling of the refrigerant is performed. Specifically, the indoor control processing device 320 performs processing such as control of the fan rotation speed of a blower (not shown) and control of the opening degree of the indoor unit expansion device 312.

  The hot water supply control processing device 420 of the hot water supply unit 410 is based on the temperature obtained from the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L, and the like. 410 has a function of controlling the degree of supercooling during heating (hot water supply) 410. Specifically, the hot water supply control processing device 420 has a function of changing the heat exchange area of the refrigerant-water heat exchanger 411 and controlling the opening degree of the hot water supply unit expansion device 412. In addition, here, a freeze prevention process is performed on the water-side flow path of the refrigerant-water heat exchanger 411 while the hot water supply unit 410 is stopped. And it is assumed that it has time measuring means (timer) for processing.

“System operation”
Next, the operation | movement which concerns on the driving | operation of the air-conditioning / hot-water supply complex system 000 is demonstrated. There are four types of operation modes that can be performed by the air conditioning and hot water supply complex system 000 of the present embodiment. First, there is a cooling operation mode in which all the indoor units 310 that are moving are cooled and the hot water supply unit 410 performs cooling. In addition, there is a heating operation mode in which all the indoor units 310 that are in operation are heated and the hot water supply unit 410 performs hot water supply (heating).

  Furthermore, when the indoor unit 310 that is heating and the indoor unit 310 that is cooling are mixed, and cooling or hot water supply is performed by the hot water supply unit 410, there is a cooling main operation mode in which the cooling and cooling loads are larger. When the indoor unit 310 that is heating and the indoor unit 310 that is cooling are mixed and the hot water supply unit 410 performs cooling or hot water supply, there is a heating main operation mode in which heating and hot water supply load are larger. With regard to the cooling main operation mode and the heating main operation mode, for example, by comparing the condensation temperature and evaporation temperature of the refrigerant of the air conditioning and hot water supply combined system 000 with target values set in the heat source unit 110, the capacity or efficiency is improved. Switch the operation mode to the highest level.

[Cooling operation mode]
FIG. 2 is a diagram showing the flow of the refrigerant in the cooling operation mode. First, the refrigerant flow and operation details in the cooling operation mode when all the indoor units 310 in operation are in the cooling operation and the hot water supply unit 410 is in the cooling operation will be described.

  In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows into the heat source side heat exchanger 113 through the flow path switching valve 112. The high-pressure gas refrigerant flowing into the heat source side heat exchanger 113 is condensed by exchanging heat with the air supplied to the heat source side heat exchanger 113 to become a high pressure liquid refrigerant, and flows out from the heat source side heat exchanger 113. . The high-pressure liquid refrigerant that has flowed out of the heat source side heat exchanger 113 flows out of the heat source unit 110 through the check valve group 116. Then, it flows through the high-pressure main pipe 001 and flows into the branch unit 210.

  In the branch unit 210, the high-pressure liquid refrigerant flowing from the high-pressure main pipe 001 flows out of the branch unit 210 through the gas-liquid separator 211 and the liquid refrigerant throttle device 212. The refrigerant flowing out from the branch unit 210 flows through the liquid branch pipe 004 and flows into the indoor unit 310 and the hot water supply unit 410. In the indoor unit 310, the indoor unit expansion device 312 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant and flows to the indoor heat exchanger 311. The low-pressure two-phase refrigerant or low-pressure liquid refrigerant that has flowed into the indoor heat exchanger 311 evaporates in the indoor heat exchanger 311, becomes a low-pressure gas refrigerant, and flows out of the indoor heat exchanger 311.

  In the hot water supply unit 410, the hot water supply unit expansion device 412 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant and flows to the refrigerant-water heat exchanger 411. The low-pressure two-phase refrigerant or low-pressure liquid refrigerant that has flowed into the refrigerant-water heat exchanger 411 evaporates in the refrigerant-water heat exchanger 411, becomes a low-pressure gas refrigerant, and flows out of the refrigerant-water heat exchanger 411.

  The low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 311 and the refrigerant-water heat exchanger 411 flows out of the indoor unit 310 and the hot water supply unit 410, then flows through the gas branch pipe 003 and flows into the branch unit 210. The low-pressure gas refrigerant that has flowed into the branch unit 210 flows to the low-pressure main pipe 002 through the electromagnetic valve 213. The low-pressure gas refrigerant that has flowed into the low-pressure main pipe 002 flows out of the branch unit 210 and then flows into the heat source unit 110. The low-pressure gas refrigerant that has flowed into the heat source unit 110 passes through the check valve group 116, the flow path switching valve 112, and the accumulator 115 and is again sucked into the compressor 111.

[Heating operation mode]
FIG. 3 is a diagram showing the flow of the refrigerant in the heating operation mode. Next, the refrigerant flow and the operation contents in the heating operation mode when all the indoor units 310 in operation are in the heating operation and the hot water supply unit 410 is in the hot water supply operation will be described.

  In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows out of the heat source unit 110 through the flow path switching valve 112 and the check valve group 116. The refrigerant that has flowed through the high-pressure main pipe 001 flows into the branch unit 210. In the branch unit 210, the high-pressure gas refrigerant flowing from the high-pressure main pipe 001 flows out of the branch unit 210 through the gas-liquid separator 211 and the electromagnetic valve 213. Then, the gas flows through the gas branch pipe 003 and flows into the indoor unit 310 and the hot water supply unit 410.

  The high-pressure gas refrigerant that has flowed into the indoor unit 310 flows into the indoor heat exchanger 311 and is condensed in the indoor heat exchanger 311. Further, in the indoor unit expansion device 312, it becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant, flows out from the indoor unit 310, flows through the liquid branch pipe 004 a, and flows into the branch unit 210.

  The high-pressure gas refrigerant that has flowed into the hot water supply unit 410 flows into the refrigerant-water heat exchanger 411, is condensed in the refrigerant-water heat exchanger 411, becomes a high-pressure liquid refrigerant, and the refrigerant-water heat exchanger. 411 flows out. The high-pressure liquid refrigerant that has flowed out of the refrigerant-water heat exchanger 411 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant in the hot water supply unit expansion device 412, and flows out of the hot water supply unit 410. It flows through the liquid branch pipe 004b and flows into the branch unit 210.

  The low-pressure refrigerant that has flowed into the branch unit 210 is merged, and then flows to the low-pressure main pipe 002 via the bypass expansion device 214. The low-pressure refrigerant flowing from the low-pressure main pipe 002 flows out from the branch unit 210 and then flows into the heat source unit 110. The refrigerant flowing into the heat source unit 110 is sucked into the compressor 111 again via the check valve group 116, the heat source side heat exchanger 113, the flow path switching valve 112, and the accumulator 115.

[Cooling operation mode]
FIG. 4 is a diagram illustrating the refrigerant flow in the cooling main operation mode. For example, the refrigerant flow and operation details in the cooling main operation mode in which the indoor unit 310 is cooling, the hot water supply unit 410 is supplying hot water, and the cooling load is larger than the heating load will be described.

  In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows into the heat source side heat exchanger 113 through the flow path switching valve 112. The high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 113 is condensed by exchanging heat with the air supplied to the heat source side heat exchanger 113 to form a two-phase refrigerant of high pressure liquid and gas, and heat source side heat exchange. Out of the vessel 113. The high-pressure two-phase refrigerant that has flowed out of the heat source side heat exchanger 113 flows out of the heat source unit 110 through the check valve group 116. Then, it flows through the high-pressure main pipe 001 and flows into the branch unit 210.

  In the branch unit 210, the high-pressure two-phase refrigerant flowing from the high-pressure main pipe 001 is separated into a high-pressure saturated gas and a high-pressure saturated liquid by the gas-liquid separator 211. The high-pressure saturated gas separated by the gas-liquid separator 211 flows out of the branch unit 210 through the electromagnetic valve 213b, flows into the hot water supply unit 410 through the gas branch pipe 003b. The refrigerant that has flowed into the hot water supply unit 410 is condensed in the refrigerant-water heat exchanger 411, becomes a high-pressure liquid refrigerant, and flows out of the refrigerant-water heat exchanger 411. The high-pressure liquid refrigerant that has flowed out of the refrigerant-water heat exchanger 411 becomes an intermediate-pressure liquid and gas two-phase refrigerant or an intermediate-pressure liquid refrigerant in the hot water supply unit expansion device 412 and flows out of the hot water supply unit 410. . Then, it flows through the liquid branch pipe 004 b and flows into the branch unit 210. The refrigerant flowing into the branch unit 210 is reused when the indoor unit 310 performs cooling.

  On the other hand, the high-pressure saturated liquid separated by the gas-liquid separator 211 merges with the refrigerant flowing from the hot water supply unit 410 via the liquid refrigerant throttling device 212. Then, the refrigerant flowing out from the branch unit 210 flows through the liquid branch pipe 004a and flows into the indoor unit 310. In the indoor unit 310, the indoor unit expansion device 312 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant and flows to the indoor heat exchanger 311. The low-pressure two-phase refrigerant or low-pressure liquid refrigerant that has flowed into the indoor heat exchanger 311 evaporates in the indoor heat exchanger 311, becomes a low-pressure gas refrigerant, and flows out of the indoor heat exchanger 311. The low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 311 flows into the branch unit 210 through the gas branch pipe 003a.

  Here, when the amount of the liquid refrigerant accumulated in the section of the liquid branch pipe 004 increases, the pressure of the liquid pipe increases. At this time, for example, if there is a heated indoor unit 310, the differential pressure with respect to the liquid pipe decreases, so the amount of refrigerant flowing through the heated indoor unit 310 decreases, and the heating capacity decreases. Therefore, in order to release the liquid accumulated in the liquid line, the bypass throttling device 214 is appropriately opened, and the liquid accumulated in the liquid line is flowed to the low-pressure main pipe 002 to adjust the pressure of the liquid line. At this time, for example, the refrigerant flowing out of the branch unit 210 is mixed with the low-pressure gas refrigerant flowing in from the indoor unit 310 and the liquid refrigerant flowing in from the bypass expansion device 214 to become a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant that has flowed into the branch unit 210 flows out of the branch unit 210 via the electromagnetic valve 213a. Then, it flows through the low pressure main pipe 002 and flows into the heat source unit 110. The low-pressure two-phase refrigerant that has flowed into the heat source unit 110 is again sucked into the compressor 111 via the check valve group 116, the flow path switching valve 112, and the accumulator 115.

[Heating main operation mode]
FIG. 5 is a diagram showing the refrigerant flow in the heating main operation mode. For example, the refrigerant flow and operation contents in the heating main operation mode in which the indoor unit 310 is heated and the hot water supply unit 410 is cooling and the heating load is larger than the cooling load will be described.

  In the heat source unit 110, the low-pressure gas refrigerant is sucked into the compressor 111, becomes a high-temperature / high-pressure gas refrigerant, and flows out of the heat source unit 110 through the flow path switching valve 112 and the check valve group 116. Then, it flows through the high-pressure main pipe 001 and flows into the branch unit 210. In the branch unit 210, the high-pressure gas refrigerant flowing from the high-pressure main pipe 001 flows out of the branch unit 210 through the gas-liquid separator 211 and the electromagnetic valve 213a, then flows in the gas branch pipe 003a, and flows into the air conditioning unit 310. To do.

  The high-pressure gas refrigerant that has flowed into the indoor unit 310 flows into the indoor heat exchanger 311 and is condensed in the indoor heat exchanger 311. Further, in the indoor unit throttle device 312, it becomes a two-phase refrigerant of medium pressure liquid and gas, or a liquid refrigerant of intermediate pressure, flows out of the indoor unit 310, flows through the liquid branch pipe 004 a, and flows into the branch unit 210. To do.

  The intermediate-pressure refrigerant flowing into the branch unit 210 flows out of the branch unit 210, flows through the liquid branch pipe 004b, and flows into the hot water supply unit 410. The refrigerant flowing into the hot water supply unit 410 becomes a low-pressure liquid and gas two-phase refrigerant or a low-pressure liquid refrigerant in the hot water supply unit expansion device 412 and flows into the refrigerant-water heat exchanger 411. The low-pressure liquid refrigerant flowing into the refrigerant-water heat exchanger 411 evaporates to become a low-pressure gas refrigerant and flows out from the hot water supply unit 410. Then, it flows through the liquid branch pipe 004 b and flows into the branch unit 210.

  Here, as in the cooling main operation mode, when the amount of liquid refrigerant accumulated in the section of the liquid branch pipe 004 increases, the pressure of the liquid pipe rises and the amount of refrigerant flowing into the indoor unit 310 that is heated decreases. , Heating capacity is reduced. Therefore, the bypass throttling device 214 is appropriately opened to adjust the liquid line pressure. At this time, for example, the low-pressure gas refrigerant flowing from the hot water supply unit 410 and the liquid refrigerant flowing from the bypass expansion device 214 are mixed to form a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant flows out of the branch unit 210 through the electromagnetic valve 213a. Then, it flows through the low pressure main pipe 002 and flows into the heat source unit 110. The low-pressure two-phase refrigerant that has flowed into the heat source unit 110 is again sucked into the compressor 111 via the check valve group 116, the flow path switching valve 112, and the accumulator 115.

[Control example 1 of hot water supply unit 410]
FIG. 6 is a diagram showing a procedure of antifreezing processing according to Embodiment 1 of the present invention. The antifreezing process in the water circuit (refrigerant-water heat exchanger 411) according to the present embodiment will be described based on FIG. This process is performed while water heating or cooling is stopped in the hot water supply unit 410, for example.

  The hot water supply control processing device 420 starts control related to the freeze prevention processing (S01i). At this time, the electromagnetic valve 213b is in a closed state, and the opening degree of the hot water supply unit expansion device 412 is basically zero.

  Then, the temperature related to detection by each temperature sensor (hot water supply unit gas pipe temperature detection sensor 413G, hot water supply unit liquid pipe temperature detection sensor 413L, inlet water temperature detection sensor 414I, outlet water temperature detection sensor 414O) provided in the hot water supply unit 410 is taken in. (S02i).

  It is determined whether or not the refrigerant pipe temperature related to detection by the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L is lower than the water circuit freezing temperature TCOLD (refrigerant pipe temperature <TCOLD) (S03i). Here, in the determination, it is determined whether any one of the refrigerant pipe temperatures related to detection by the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L is lower than the water circuit freezing temperature TCOLD. Alternatively, it may be determined whether or not both are lower than the water circuit freezing temperature TCOLD. If it is determined in the process of S03i that each refrigerant pipe temperature is not lower than the water circuit freezing temperature TCOLD (the refrigerant pipe temperature is equal to or higher than the water circuit freezing temperature TCOLD), the process ends (S08i).

  On the other hand, for example, when cooling is performed in the indoor unit 310, the pressure of the liquid refrigerant may be high. When the hot water supply unit expansion device 412 is not fully closed, the refrigerant decompressed in the hot water supply unit expansion device 412 flows into the refrigerant-water heat exchanger 411. For this reason, the water in the refrigerant-water heat exchanger 411 is cooled by the refrigerant. Therefore, in the process of S03i, if it is determined that the refrigerant pipe temperature is lower than the water circuit freezing temperature TCOLD, the hot water supply unit expansion device 412 is raised (opened) to an arbitrary opening A (A> 0) (S04i). By increasing the opening, pressure loss in the pipe between the branch unit 210 and the hot water supply unit 410 can be reduced. Thereby, the pressure of the refrigerant in the refrigerant-water heat exchanger 411 is increased from a low pressure to an intermediate pressure. Since the refrigerant piping temperature rises due to the increase in pressure, it is possible to avoid heat exchanger damage due to freezing of the water circuit portion of the refrigerant-water heat exchanger 411 in the hot water supply unit 410.

  Here, even if the hot water supply unit expansion device 412 is opened to an arbitrary opening degree, the refrigerant pipe temperature does not rise instantaneously. Therefore, it is determined whether or not an elapsed time after opening the opening of the hot water supply unit expansion device 412 is equal to or longer than an arbitrary set time (S05i). Then, the opening degree is maintained at the current state until it is determined that the set time is exceeded (S07i). If it is determined that the set time has elapsed, the opening degree of the hot water supply unit expansion device 412 is returned to the original state (S06i), and the process is terminated (S08i). The above processing is performed while water heating or cooling is stopped in the hot water supply unit 410.

  As described above, according to the air conditioning and hot water supply combined system of the first embodiment, when the hot water supply unit 410 is stopped, for example, the opening degree of the hot water supply unit expansion device 412 is not closed and there is a refrigerant leak or the like. If the refrigerant temperature in the refrigerant-water heat exchanger 411 decreases and the refrigerant pipe temperature is determined to be lower than the water circuit freezing temperature TCOLD, the opening of the hot water supply unit expansion device 412 is opened to the opening A. Since the temperature on the refrigerant side in the refrigerant-water heat exchanger 411 is increased to increase the temperature, water freezing in the refrigerant-water heat exchanger 411 can be prevented. For this reason, breakage of the refrigerant-water heat exchanger 411 can be prevented.

Embodiment 2. FIG.
[Control example 2 of hot water supply unit 410]
FIG. 7 is a diagram showing a procedure of anti-freezing processing according to Embodiment 2 of the present invention. In the processing related to prevention of freezing of water in the refrigerant-water heat exchanger 411 in the first embodiment described above, for example, in FIG. 6, when the set time elapses based on the processing of S05i, S06i, and S07i, The expansion device 412 was closed.

  However, closing the open hot water supply unit expansion device 412 may impair the stability of the refrigeration cycle in the refrigerant circuit. Further, when the hot water supply unit expansion device 412 is closed, there is a concern that the hot water supply unit 410 (refrigerant-water heat exchanger 411) may be damaged because the refrigerant is sealed in the refrigerant-water heat exchanger 411. . Therefore, in this embodiment, when the hot water supply unit expansion device 412 is opened to an arbitrary opening degree, the processing of S06i, S07i, and S08i is not performed, and the hot water supply unit 410 is closed while the heating or cooling of water is stopped. Do not do.

Embodiment 3 FIG.
[Control example 3 of hot water supply unit 410]
FIG. 8 is a diagram showing a procedure of anti-freezing processing according to Embodiment 3 of the present invention. In the above-described first and second embodiments, when the temperature of the water in the refrigerant-water heat exchanger 411 decreases, the opening degree of the hot water supply unit expansion device 412 is adjusted to prevent freezing. In this embodiment, the solenoid valve 213b is switched to prevent freezing.

  The hot water supply control processing device 420 starts control related to the freeze prevention processing (S11i). At this time, the electromagnetic valve 213b is in a closed state, and the opening degree of the hot water supply unit expansion device 412 is basically zero.

  Then, the temperature related to detection by each temperature sensor (hot water supply unit gas pipe temperature detection sensor 413G, hot water supply unit liquid pipe temperature detection sensor 413L, inlet water temperature detection sensor 414I, outlet water temperature detection sensor 414O) provided in the hot water supply unit 410 is taken in. (S12i).

  It is determined whether or not the refrigerant pipe temperatures related to detection by the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L are both lower than the water circuit freezing temperature TCOLD (S13i). Here, in the determination, as in the process of S03i described in the first embodiment, one of the refrigerant pipe temperatures related to detection by the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L is water. It may be determined whether the temperature is lower than the circuit freezing temperature TCOLD or whether both are lower than the water circuit freezing temperature TCOLD. If it is determined in S13i that each refrigerant pipe temperature is not lower than the water circuit freezing temperature TCOLD (the refrigerant pipe temperature is equal to or higher than the water circuit freezing temperature TCOLD), the process ends (S18i).

  On the other hand, when it is determined that the refrigerant pipe temperature is lower than the water circuit freezing temperature TCOLD, an instruction is sent to the branch control processing device 220 of the branch unit 210, and the gas branch pipe 003b (refrigerant-water heat exchanger 411) and the gas-liquid separator are sent. The opening and closing of the electromagnetic valve 213b is controlled so as to communicate with the 211 (S14i). For example, the pressure in the refrigerant-water heat exchanger 411 is set to an intermediate pressure by connecting the gas-liquid separator 211 -the solenoid valve 213b -the gas branch pipe 003b -the hot water supply unit 410 (refrigerant-water heat exchanger 411). Can do. As the pressure in the refrigerant-water heat exchanger 411 changes from a low pressure to an intermediate pressure and the pressure rises, the refrigerant piping temperature rises. For this reason, damage to the heat exchanger due to freezing of water in the refrigerant-water heat exchanger 411 of the hot water supply unit 410 can be avoided.

  Here, even if the gas branch pipe 003b and the gas-liquid separator 211 communicate with each other, the refrigerant pipe temperature does not rise instantaneously. Therefore, it is determined whether the elapsed time after controlling the electromagnetic valve 213b is longer than an arbitrary set time (S15i). Then, the solenoid valve 213b is maintained at the current state until it is determined that the set time has been exceeded (S17i). If it is determined that the set time has elapsed, the solenoid valve 213b is closed (S16i), and the process is terminated (S18i). The above processing is performed while water heating or cooling is stopped in the hot water supply unit 410. Here, as in the above-described second embodiment, the processing of S15i to S17i may not be performed depending on circumstances.

  As described above, according to the combined air conditioning and hot water supply system of Embodiment 3, for example, when the hot water supply unit 410 is stopped, if it is determined that the refrigerant pipe temperature is lower than the water circuit freezing temperature TCOLD, the branch unit 210 The solenoid valve 213 is controlled so that the gas-liquid separator 211 and the refrigerant-water heat exchanger 411 are opened to increase the pressure on the refrigerant side in the refrigerant-water heat exchanger 411 so as to increase the temperature. Therefore, freezing of water in the refrigerant-water heat exchanger 411 can be prevented. For this reason, breakage of the refrigerant-water heat exchanger 411 can be prevented.

Embodiment 4 FIG.
In the above-described embodiment, it is determined whether or not the temperature of the hot water supply unit gas pipe temperature detection sensor 413G and the hot water supply unit liquid pipe temperature detection sensor 413L is lower than the water circuit freezing temperature TCOLD. is not. For example, it may be determined whether the inlet water temperature detection sensor 414I and the outlet water temperature detection sensor 414O are smaller than the water circuit freezing temperature TCOLD.

Embodiment 5 FIG.
In the above-described embodiment, in order to perform hot water supply (water supply), water is used as an object for heat exchange with the refrigerant in the refrigerant-water heat exchanger 411. However, the present invention is not limited to this. For example, when there is a possibility that the water pipe 010 will freeze in an environment where the water in the refrigerant-water heat exchanger 411 has a low water temperature, an antifreeze (brine) may be added to the water. The type of antifreeze is not particularly limited, and may be selected according to availability and use, such as ethylene glycol and propylene glycol.

  000 air-conditioning hot water supply complex system, 001 high pressure main pipe, 002 low pressure main pipe, 003, 003a, 003b gas branch pipe, 004, 004a, 004b liquid branch pipe, 010 water pipe, 110 heat source unit, 111 compressor, 112 flow path switching valve, 113 heat source side heat exchanger, 114 blower, 115 accumulator, 116 check valve group, 117H discharge pressure sensor, 117L suction pressure sensor, 118H discharge temperature sensor, 118L suction temperature sensor, 119a heat source heat exchanger temperature sensor, 119b outside air Temperature sensor, 120 Heat source control processing device, 210 Branch unit, 211 Gas-liquid separator, 212 Liquid refrigerant throttle device, 213, 213a, 213b Solenoid valve, 214 Bypass throttle device, 215 Branch pressure sensor, 220 Branch control processing device, 3 0 indoor unit, 311 indoor heat exchanger, 312 indoor unit expansion device, 313G indoor unit gas pipe temperature detection sensor, 313L indoor unit liquid pipe temperature detection sensor, 314 indoor air temperature sensor, 320 indoor control processing device, 410 hot water supply unit, 411 Refrigerant-water heat exchanger, 412 Hot water supply unit throttle device, 413G Hot water supply unit gas pipe temperature detection sensor, 413L Hot water supply unit liquid pipe temperature detection sensor, 414I Inlet water temperature detection sensor, 414O Outlet water temperature detection sensor, 420 Hot water supply control processing device.

Claims (6)

At least one heat source unit having a compressor and a heat source side heat exchanger;
At least one indoor unit having an indoor heat exchanger and an indoor expansion device;
At least one hot water supply unit having a refrigerant-water heat exchanger and a hot water supply side throttle device;
A gas-liquid separator that supplies a gaseous refrigerant to the indoor unit and / or the hot water supply unit that heats the heat exchange target, and supplies a liquid refrigerant to the indoor unit and / or the hot water supply unit that cools the heat exchange target; A refrigerant circuit is constructed by pipe-connecting a branch unit having a refrigerant flow path control device that controls passage of the refrigerant to the indoor unit and the hot water supply unit,
When it is determined that the water in the water-side flow path in the refrigerant-water heat exchanger may freeze while the hot water supply unit is stopped, the pressure in the refrigerant-side flow path of the refrigerant-water heat exchanger , An air conditioning and hot water supply complex system including a control processing device that performs control to reduce a pressure difference between a refrigerant side flow path of the refrigerant-water heat exchanger and a pressure of a pipe connected via the hot water supply side throttle device .   The said control processing apparatus performs the process which opens the opening degree of the said hot water supply side expansion apparatus to a predetermined opening degree, when it judges that the water in the said refrigerant | coolant-water heat exchanger may freeze. Air conditioning and hot water supply combined system.   When the control processing device determines that there is a possibility that water in the refrigerant-water heat exchanger is frozen, the refrigerant-side flow channel of the refrigerant-water heat exchanger and the gas-liquid are added to the refrigerant flow control device. The combined air conditioning and hot water supply system according to claim 1, wherein the gas supply side of the separator is in communication.   The air conditioning and hot water supply complex system according to any one of claims 1 to 3, wherein when the control processing device determines that a predetermined time has elapsed after performing control to increase pressure, the control processing device performs processing to return to a state before control. Refrigerant side temperature detection means for detecting the temperature in the refrigerant side flow path in the refrigerant-water heat exchanger is further provided,
The said control processing apparatus is an air-conditioning hot-water supply complex system in any one of Claims 1-4 which judges the possibility of freezing based on the temperature which the said refrigerant | coolant side temperature detection means detects. The refrigerant - further comprising a water-side temperature detection means for detecting the temperature in the water-side flow channel in the water heat exchanger,
The said control processing apparatus is an air-conditioning hot-water supply complex system in any one of Claims 1-4 which determines the possibility of freezing based on the temperature which the said water side temperature detection means detects.

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