JP4075072B2 - Heat pump circuit for air conditioning - Google Patents

Description

  The present invention relates to a heat pump circuit for air conditioning.

  A heat source side heat exchanger, a compressor, and a plurality of air supply side heat exchangers are provided. For example, air cooling (cooling) is performed with one air supply side heat exchanger, and air heating (heating) is performed with the other air supply side heat exchanger. As a heat pump circuit for air conditioning, there is one disclosed in JP-A-61-110859. The refrigerant outlet of the compressor is connected to the high-pressure gas pipe, the refrigerant inlet is connected to the low-pressure gas pipe, and one of the refrigerant inlets and outlets of the heat source side heat exchanger is switchably connected to the high-pressure gas pipe and the low-pressure gas pipe. The other of the refrigerant inlet / outlet of the heat source side heat exchanger is connected to the liquid pipe via an expansion valve, and one of the refrigerant inlet / outlet of each air supply side heat exchanger is connected to the high pressure gas pipe and the low pressure gas pipe in a switchable manner, The other refrigerant inlet / outlet of each air supply side heat exchanger is connected to a liquid pipe via an expansion valve.

JP-A-61-110859

  In such a configuration, there is a problem that an expansion valve is required for each heat exchanger, the circuit is complicated, and it takes time and effort to manufacture. In addition, when an electronic expansion valve is used, control of each expansion valve is necessary and the control becomes complicated.

  In order to solve the above-described problems, the present invention provides a heat source side heat exchanger and a plurality of air supply side heat exchangers that perform an evaporation process and a condensation process of the circulating refrigerant, a compressor that compresses the circulating refrigerant, and the circulating refrigerant is expanded. An expansion valve, a low-pressure liquid pipe and a high-pressure liquid pipe, and a low-pressure gas pipe and a high-pressure gas pipe. The refrigerant outlet of the compressor is connected to the high-pressure gas pipe and the refrigerant inlet of the compressor is connected to the low-pressure gas pipe. Connected to a gas pipe, one of the refrigerant inlets and outlets of the heat source side heat exchanger is switchably connected to the high pressure gas pipe and the low pressure gas pipe, and the other of the refrigerant inlets and outlets of the heat source side heat exchanger is connected to the high pressure gas A liquid pipe and a low-pressure liquid pipe are switchably connected, and one of the refrigerant inlets and outlets of each of the supply-side heat exchangers is switchably connected to the high-pressure gas pipe and the low-pressure gas pipe. The other side of the refrigerant inlet / outlet of the heat exchanger is connected to the high pressure liquid pipe and the low pressure liquid. Switching freely connected to the most important feature that the said low-pressure liquid pipe between the high pressure liquid pipe is connected through the expansion valve.

According to the first aspect of the present invention, only one expensive expansion valve is required, the structure is simplified and piping work is facilitated, so that the size can be reduced, the cost can be reduced, and the control can be simplified. Control of connection switching between the other refrigerant inlet / outlet of each air supply side heat exchanger, the high pressure liquid pipe and the low pressure liquid pipe, and connection between the other refrigerant inlet / outlet of the heat source side heat exchanger, the high pressure liquid pipe and the low pressure liquid pipe Switching control is unnecessary, and it is not necessary to use expensive three-way valves or electromagnetic on-off valves, thereby reducing costs.

  FIG. 1 shows an embodiment of an air conditioning heat pump circuit according to the present invention. This air conditioning heat pump circuit repeats the steps of evaporation, compression, condensation, and expansion with respect to the circulating refrigerant. In the refrigerant evaporation process, heat is absorbed in the refrigerant evaporation process with respect to the air or heat source water to be exchanged, and at least one heat source side heat exchanger 1 and a plurality of supply air that perform the evaporation process and the condensation process of the circulating refrigerant A side heat exchanger 2... A compressor 3 that compresses the circulating refrigerant, an expansion valve 4 such as a temperature automatic expansion valve or an electronic expansion valve that expands the circulating refrigerant, a low pressure liquid pipe A and a high pressure liquid pipe B, and a low pressure At least a gas pipe C and a high-pressure gas pipe D are provided. For example, an air conditioner 10 as shown in FIG. To supply air to the air-conditioning zone. It rolling only, carried out simultaneous heating and cooling operation, the freely switching. The supply-side heat exchanger 2 is an air-cooling type that exchanges heat with supply air, and the heat-source-side heat exchanger 1 exchanges heat using a water-cooling type that exchanges heat using a water heat source medium and an air heat source medium. Although the air cooling method may be used, the drawing illustrates the water cooling method.

  As shown in FIG. 1, the refrigerant outlet of the compressor 3 is connected to the high-pressure gas pipe D, the refrigerant inlet of the compressor 3 is connected to the low-pressure gas pipe C, and one of the refrigerant inlets and outlets of the heat source side heat exchanger 1 is The high-pressure gas pipe D and the low-pressure gas pipe C are branched and connected via the on-off valves 8a and 8b, and are connected to the high-pressure gas pipe D and the low-pressure gas pipe C so as to be switchable. The other is branchedly connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A, and the first check valve 5a for flowing the refrigerant only in the direction of the high-pressure liquid pipe is provided in the first branch pipe on the high-pressure liquid pipe side. The second branch pipe on the pipe side is provided with a second check valve 5b that allows the refrigerant to flow only in the direction of the heat source side heat exchanger, and is connected to the high pressure liquid pipe B and the low pressure liquid pipe A in a switchable manner, and heat source side heat exchange is performed. An on-off valve 9 is provided between the other refrigerant inlet / outlet of the vessel 1 and the first and second branch pipes.

  Furthermore, one of the refrigerant inlets and outlets of each supply side heat exchanger 2 is branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via the on-off valves 8a and 8b, so that the high-pressure gas pipe D and the low-pressure gas pipe C are connected. The other refrigerant inlet / outlet of each air supply side heat exchanger 2 is branched and connected to the high pressure liquid pipe B and the low pressure liquid pipe A, and the third branch pipe on the high pressure liquid pipe side is connected to the high pressure liquid. A third check valve 6a for flowing the refrigerant only in the pipe direction is provided, and a fourth check valve 6b for flowing the refrigerant only in the direction of the supply air heat exchanger is provided in the fourth branch pipe on the low pressure liquid pipe side, A high-pressure liquid pipe B and a low-pressure liquid pipe A are switchably connected, and an on-off valve 7 is provided between the other refrigerant inlet / outlet of each air supply side heat exchanger 2 and the third and fourth branch pipes. The pipe B and the low-pressure liquid pipe A are connected via the expansion valve 4. Although not shown, when the expansion valve 4 is an electronic expansion valve, the expansion valve is operated and controlled by the refrigerant temperature and refrigerant pressure of the compressor 3. As the on-off valves 7, 8a, 8b, 9, solenoid valves or the like are used.

  When the cooling operation is performed by the air conditioner 10 provided with the heat pump circuit for air conditioning, the on-off valve 8a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of the heat source side heat exchanger 1 is opened and the low-pressure gas pipe as shown in FIG. Side open / close valve 8b is closed, one open / close valve 8b on the high-pressure gas pipe side of the refrigerant inlet / outlet of the two supply-side heat exchangers 2 is closed, and open / close valve 8b on the low-pressure gas pipe side is opened. , 9 is opened. As a result, the refrigerant flows from the compressor 3 to the heat source side heat exchanger 1 in a high pressure gas state, condenses and flows to the expansion valve 4 in a high pressure liquid state, and is decompressed to one supply side heat exchanger in a low pressure liquid state. 2 and the other supply air side heat exchanger 2, each of which is evaporated and merged in a low-pressure gas state and returned to the compressor 3, and this cycle is repeated. In this way, the air supply air is cooled by the air supply side heat exchanger 2 to perform the cooling operation. When only one of the air supply side heat exchangers 2 is to be cooled, the opening / closing valve 7 on the operation side is opened. The on-off valve 7 on the open and stop sides is closed. In the illustrated example, a closed state is indicated by a solid on-off valve, an open state is indicated by an unopened on-off valve, a refrigerant flow state is indicated by a solid line, and a refrigerant stop state is indicated by a dotted line.

  Next, in the case of heating operation, as shown in FIG. 4, one of the refrigerant inlets and outlets of the heat source side heat exchanger 1 is closed on the high pressure gas pipe side on-off valve 8 a and the low pressure gas pipe side on-off valve 8 b is opened, The on-off valve 8a on the high-pressure gas pipe side of the refrigerant inlet / outlet of the two supply-side heat exchangers 2 is opened, the on-off valve 8b on the low-pressure gas pipe side is closed, and the on-off valves 7 and 9 are opened. As a result, the refrigerant is diverted from the compressor 3 to the one supply side heat exchanger 2 and the other supply side heat exchanger 2 in the high pressure gas state, condenses and merges in the high pressure liquid state to expand the expansion valve 4. Then, the pressure is reduced and flows to the heat source side heat exchanger 1 in a low-pressure liquid state, evaporates and returns to the compressor 3 in a low-pressure gas state, and this cycle is repeated. In this way, the air supply side heat exchanger 2 heats the supply air to perform the heating operation. When only one of the air supply side heat exchangers 2 performs the heating operation, the operation side on-off valve 7 is turned on. The on-off valve 7 on the open and stop sides is closed.

  Next, when the heating operation and the cooling operation are performed at the same time and there is a difference between the heating load and the cooling load and the cooling load is larger, one high-pressure gas pipe at the refrigerant inlet / outlet of the heat source side heat exchanger 1 as shown in FIG. The open / close valve 8a on the side and the open / close valve 8b on the low-pressure gas pipe side are closed, and the open / close valve 8a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of one supply-side heat exchanger 2 (left side in the figure) is opened. The on-off valve 8b on the open and low-pressure gas pipe side is closed, and the on-off valve 8a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of the other air supply side heat exchanger 2 (right side in the example) is closed and on the low-pressure gas pipe side The on-off valve 8b is opened, and the on-off valves 7 and 9 are opened. As a result, the refrigerant is split from the compressor 3 into the heat source side heat exchanger 1 and one of the air supply side heat exchangers 2 in a high pressure gas state, condensed and joined in a high pressure liquid state to the expansion valve 4. The pressure is reduced and the refrigerant flows into the other supply-side heat exchanger 2 in the low-pressure liquid state, evaporates and returns to the compressor 3 in the low-pressure gas state, and this cycle is repeated. In this way, one of the supply-side heat exchangers 2 heats the supply air to perform heating operation, and the other supply-side heat exchanger 2 cools the supply air to perform cooling operation. Do.

  Next, when the heating operation and the cooling operation are performed at the same time and there is a difference between the heating load and the cooling load and the heating load is larger, as shown in FIG. 6, one high-pressure gas pipe at the refrigerant inlet / outlet of the heat source side heat exchanger 1 Side open / close valve 8a is closed and low pressure gas pipe side open / close valve 8b is opened, and one high pressure gas pipe side open / close valve 8a on the refrigerant inlet / outlet side of one air supply side heat exchanger 2 (left side in the figure) is opened. The on-off valve 8b on the open and low-pressure gas pipe side is closed, and the on-off valve 8a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of the other air supply side heat exchanger 2 (right side in the example) is closed and on the low-pressure gas pipe side The on-off valve 8b is opened, and the on-off valves 7 and 9 are opened. As a result, the refrigerant flows from the compressor 3 to the one supply side heat exchanger 2 in the high pressure gas state, condenses and flows to the expansion valve 4 in the high pressure liquid state, and is decompressed to the heat source side heat exchanger in the low pressure liquid state. 1 and the other air supply side heat exchanger 2 are diverted, and each is evaporated and merged in a low-pressure gas state and returned to the compressor 3, and this cycle is repeated. In this way, one of the supply-side heat exchangers 2 heats the supply air to perform heating operation, and the other supply-side heat exchanger 2 cools the supply air to perform cooling operation. Do.

  Although not shown in the drawings, when the heating load and the cooling load are balanced in the operations shown in FIGS. 5 and 6, by simultaneously closing the on-off valve 9, the simultaneous cooling and heating operation can be performed without using the heat source side heat exchanger 1. Energy saving. Further, a plurality of heat source side heat exchangers 1 are provided, and one of the refrigerant inlets and outlets of each heat source side heat exchanger 1 is branched and connected to the high pressure gas pipe D and the low pressure gas pipe C via the on-off valves 8a and 8b. The high-pressure gas pipe D and the low-pressure gas pipe C are switchably connected, and the other refrigerant inlet / outlet of each heat source side heat exchanger 1 is branched and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A. A first check valve 5a that allows the refrigerant to flow only in the direction of the high-pressure liquid pipe is provided in the first branch pipe, and a second reverse flow in which the refrigerant flows only in the direction of the heat source side heat exchanger in the second branch pipe on the low-pressure liquid pipe side. A stop valve 5b is provided and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A in a switchable manner, and the on-off valve 9 is provided between the other refrigerant inlet / outlet of each heat source side heat exchanger 1 and the first and second branch pipes. May be provided. Furthermore, the number of the supply side heat exchanger 2, the on-off valves 7, 8a, 8b, 9 and the check valves 6a, 6b can be increased or decreased, and the on-off valve 9 can be omitted. One of the refrigerant inlets and outlets of the supply side heat exchanger 2 is branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via a three-way valve so that the high-pressure gas pipe D and the low-pressure gas pipe C can be switched. Can be connected, or one of the refrigerant inlets and outlets of the heat source side heat exchanger 1 can be branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via a three-way valve to switch between the high-pressure gas pipe D and the low-pressure gas pipe C. You may connect to. Similarly, the other refrigerant inlet / outlet of the supply side heat exchanger 2 is branched and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A via a three-way valve so that the high-pressure liquid pipe B and the low-pressure liquid pipe A can be switched. Or the other refrigerant inlet / outlet of the heat source side heat exchanger 1 is branched and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A via a three-way valve to switch to the high-pressure liquid pipe B and the low-pressure liquid pipe A. You may connect freely.

An example of a heat pump circuit for air conditioning. Explanatory drawing of the air conditioner using this invention. Explanatory drawing of air_conditionaing | cooling operation. Explanatory drawing of heating operation. Explanatory drawing of air-conditioning simultaneous operation. Explanatory drawing of other air-conditioning simultaneous operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat source side heat exchanger 2 Supply air side heat exchanger 3 Compressor 4 Expansion valve 5a First check valve 5b Second check valve 6a Third check valve 6b Fourth check valve A Low pressure liquid pipe B High pressure liquid Pipe C Low pressure gas pipe D High pressure gas pipe

Claims (1)

A heat source side heat exchanger 1 and a plurality of air supply side heat exchangers 2 that perform an evaporation process and a condensation process of the circulating refrigerant, a compressor 3 that compresses the circulating refrigerant, an expansion valve 4 that expands the circulating refrigerant, and a low pressure At least a liquid pipe A and a high-pressure liquid pipe B, a low-pressure gas pipe C, and a high-pressure gas pipe D. The refrigerant outlet of the compressor 3 is connected to the high-pressure gas pipe D and the refrigerant inlet of the compressor 3 is connected. Connected to the low-pressure gas pipe C, one of the refrigerant inlets and outlets of the heat source side heat exchanger 1 is branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via on-off valves 8a and 8b, The high pressure gas pipe D and the low pressure gas pipe C are switchably connected, and the other refrigerant inlet / outlet of the heat source side heat exchanger 1 is branched and connected to the high pressure liquid pipe B and the low pressure liquid pipe A. The first branch pipe on the pipe side is provided with a first check valve 5a that allows the refrigerant to flow only in the direction of the high-pressure liquid pipe. And the second branch of the low-pressure liquid pipe side is provided a second check valve 5b to flow only refrigerant to the heat source-side heat exchanger direction, switching freely connected to the high pressure liquid pipe B and the low-pressure liquid pipe A One of the refrigerant inlets and outlets of each supply side heat exchanger 2 is branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via on-off valves 8a and 8b, and the high-pressure gas pipe D and the The low-pressure gas pipe C is switchably connected, and the other refrigerant inlet / outlet of each of the supply-side heat exchangers 2 is branched and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A, and the high-pressure liquid pipe side The third branch valve is provided with a third check valve 6a for flowing the refrigerant only in the direction of the high-pressure liquid pipe, and the fourth reverse flow of the refrigerant in the fourth branch pipe on the low-pressure liquid pipe side only in the direction of the air supply side heat exchanger. provided check valve 6b, the high pressure liquid pipe connected switching freely B and the low-pressure liquid pipe a, the expansion of said high pressure liquid pipe B and the low-pressure liquid pipe a Air-conditioning heat pump circuit, characterized in 4 via the connected.

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