JP4203758B2 - Water-cooled heat pump type ground-heated air conditioning system - Google Patents

Description

  The present invention relates to a water-cooled heat pump type underground heat utilization air conditioning system.

  As a system for air conditioning using geothermal heat, equipped with a water-cooled heat pump type air conditioner, and a ground heat exchanger (ground heat exchange well) that adjusts the temperature of the heat medium used in the air conditioner with ground heat Some air conditioners and underground heat exchangers are directly connected by piping and circulated, and a heat medium whose temperature is adjusted by the underground heat exchanger is flowed to the air conditioners for air conditioning. In this system, a water-cooled heat pump type air conditioner is individually provided for each air-conditioning zone, and individual air-conditioning is possible by dividing the heat medium.

JP 2003-207174 A JP-A-61-110859

  However, since there are always vacant rooms even in hospitals and hotels that require individual air conditioning, it is not necessary to air-condition all the zones. Moreover, since antifreeze is used for the heat medium, water quality management and disposal are troublesome. Also, 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 is heated with the other air supply side heat exchanger. As a heat pump circuit for air conditioning that can be (heated), 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. 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, individual expansion valve control is required and the control becomes complicated.

  In order to solve the above problems, the present invention is a water-cooled heat pump type air conditioner that divides air and supplies air to a plurality of zones individually as air volume controllable, a geothermal heat exchanger that adjusts the water temperature by underground heat, Was piped so that the heat source water circulated. In addition, the heat source water circulates in the water tank, a water-cooled heat pump air conditioner that divides the air and supplies air to the multiple zones individually as air volume control is possible, and an underground heat exchanger that adjusts the water temperature using underground heat. Piping was done. In addition, the first and second water tanks, the heat source water circuit for sending water from the first water tank to the second water tank, the water in the heat source water circuit is passed, and the air is diverted to a plurality of zones. A water-cooled heat pump type air conditioner that individually feeds air volume as freely controllable, and a geothermal exchange channel that sends water from the second water tank to the first water tank in a flow-adjustable manner and adjusts the water temperature by geothermal heat, and The main feature is that the two water tanks and the first water tank are communicated with each other through a bypass water channel, and an open / close valve is provided in the bypass water channel.

According to the invention of claim 1 , since the total air-conditioning capacity may be small compared with the case where a water-cooled heat pump type air conditioner is individually provided for each air-conditioning zone, the cost can be reduced by eliminating waste of equipment and operation. You can save. It is only necessary to provide a water tank between the air conditioner and the underground heat exchanger, and the structure is simple and the equipment cost is low. Depending on the load condition of the air conditioner operation, the water supply to the geothermal exchange channel can be stopped and the heat source water can be circulated only between the water tank and the air conditioner, so that the operation cost can be reduced and the energy is saved. In addition, when warming up to bring the heat source water to the specified water temperature range before operating the air conditioner, the water supply to the heat source water circuit is stopped and the heat source water can be circulated only between the water tank and the geothermal exchange water channel. Costs can be saved and energy can be saved. Since the return water whose temperature has changed due to heat exchange with the air conditioner is sent to the second tank, the water temperature in the first tank does not change due to the mixing of the return water, the air source heat temperature is stabilized, and the compressor load of the water-cooled heat pump In addition, since the temperature difference between the water from the second tank and the ground becomes large, more natural geothermal energy can be used and energy saving can be achieved.
According to the invention of claim 2 , stable water temperature control can be performed by both geothermal and auxiliary heat sources, and troubles due to water freezing can be prevented. Since water is used as heat source water, it is troublesome in water quality management and disposal processing compared to antifreeze liquid. It does not take. It is also possible to use only one of geothermal and auxiliary heat sources and use the other for backup in the event of a failure. Since the water temperature of only one of the first water tanks may be adjusted supplementarily, the capacity of the auxiliary heat source machine can be reduced and energy can be saved.
According to the invention of claim 3 , 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 is simplified.

  1 to 3 show a first embodiment of a water-cooled heat pump type underground heat-use air conditioning system according to the present invention. This water-cooled heat pump type underground heat-use air conditioning system is configured to divide air into a plurality of zones. A water-cooled heat pump type air conditioner 3 that supplies air so that the air volume can be controlled individually and a ground heat exchanger 9 that adjusts the water temperature by underground heat are piped so that the heat source water circulates. The heat source water is sent in the direction of the arrow so that the flow rate can be adjusted by a water pump, and after heat exchange is performed in the heat source side water heat exchanger 14 of the water-cooled heat pump type air conditioner 3, the water temperature is adjusted in the underground heat exchanger 9. Circulate. The underground heat exchanger 9 is buried in the ground and heat-exchanges the heat source water by underground heat. In the illustrated example, the underground heat exchanger 9 shows a U-shaped underground heat exchange well, but may be other.

  The casing 11 of the water-cooled heat pump type air conditioner 3 is provided with a plurality of air supply side air passages 15 (two in the illustrated example), and refrigerant evaporation / refrigerant condensation switching is individually performed for each air supply side air passage 15. A free air supply side air heat exchanger 12 and a blower 13 are provided so that one water-cooled heat pump type air conditioner 3 can be cooled and heated simultaneously in one zone and heated in another zone. Each air supply side air passage 15 is provided with a return air port, an outside air intake port that can control the air volume, and a plurality of air supply ports, and communicates with each zone through a duct, an air outlet, and a suction port, and circulates in a central manner. Ventilation is performed with the exhaust port 16 and the ventilation fan 17 while air conditioning. In the example shown in the figure, an air conditioning system using variable air volume (VAV) is illustrated, but other systems may be freely used. Further, the humidifier 18 performs humidity adjustment as a separate installation (not shown) in the casing 11 or in the room.

  The water-cooled heat pump of the water-cooled heat pump type air conditioner 3 repeats the steps of evaporation, compression, condensation, and expansion with respect to the circulating refrigerant, and the refrigerant absorbs heat in the refrigerant evaporation step with respect to air and heat source water that exchanges heat with the circulating refrigerant. Each of them performs heat dissipation in the condensation process, and includes a heat source side water heat exchanger 14 and a plurality of air supply side air heat exchangers 12 that perform the evaporation process and the condensation process of the circulating refrigerant, and a compressor 19 that compresses the circulating refrigerant. And an expansion valve 20 such as an automatic temperature expansion valve or an electronic expansion valve for expanding the circulating refrigerant, a low pressure liquid pipe A and a high pressure liquid pipe B, a low pressure gas pipe C and a high pressure gas pipe D, and a compressor 19. The refrigerant outlet of the compressor 19 is connected to the high pressure gas pipe D, the refrigerant inlet of the compressor 19 is connected to the low pressure gas pipe C, and one of the refrigerant inlets and outlets of the heat source side water heat exchanger 14 is connected to the high pressure gas pipe D and the low pressure gas pipe C. And through the on-off valves 23a and 23b. The high-pressure gas pipe D and the low-pressure gas pipe C are switchably connected, the other refrigerant inlet / outlet of the heat source side water heat exchanger 14 is branched and connected to the high-pressure liquid pipe B and the low-pressure liquid pipe A. The first branch pipe on the liquid pipe side is provided with a first check valve 21a that allows the refrigerant to flow only in the direction of the high pressure liquid pipe, and the second branch pipe on the low pressure liquid pipe side has the refrigerant only in the direction of the heat source side water heat exchanger. The second check valve 21b is provided to connect the high-pressure liquid pipe B and the low-pressure liquid pipe A so that they can be switched, and the other refrigerant inlet / outlet of the heat source side water heat exchanger 14 is connected to the first and second branch pipes. An on-off valve 25 is provided between them.

  One of the refrigerant inlets and outlets of each air supply side air heat exchanger 12 is branched and connected to the high-pressure gas pipe D and the low-pressure gas pipe C via the open / close valves 23a and 23b, and is connected to the high-pressure gas pipe D and the low-pressure gas pipe C. The other refrigerant inlet / outlet of each air supply side air heat exchanger 12 is branched and connected to the high pressure liquid pipe B and the low pressure liquid pipe A, and the high pressure liquid is connected to the third branch pipe on the high pressure liquid pipe side. A third check valve 22a for flowing the refrigerant only in the pipe direction is provided, and a fourth check valve 22b for flowing the refrigerant only in the direction of the air supply side air heat exchanger is provided in the fourth branch pipe on the low pressure liquid pipe side. The high-pressure liquid pipe B and the low-pressure liquid pipe A are switchably connected, and an on-off valve 24 is provided between the other refrigerant inlet / outlet of each air supply side air heat exchanger 12 and the third and fourth branch pipes, The high pressure liquid pipe B and the low pressure liquid pipe A are connected via the expansion valve 20. If the first, second, third, and fourth check valves 21a, 21b, 22a, and 22b are thus provided, the other refrigerant inlet / outlet of each air supply side air heat exchanger 12 and the high-pressure liquid pipe are provided. Control of connection switching between B and the low-pressure liquid pipe A, and control of connection switching between the other refrigerant inlet / outlet of the heat source side water heat exchanger 14, the high-pressure liquid pipe B, and the low-pressure liquid pipe A are not necessary, and This eliminates the need for expensive three-way valves and electromagnetic on-off valves, thus reducing costs. Although not shown, when the expansion valve 20 is an electronic expansion valve, the expansion valve is operated and controlled by the refrigerant temperature and the refrigerant pressure of the compressor 19. As the on-off valves 24, 23a, 23b, 25, electromagnetic valves or the like are used. The heat source side water heat exchanger 14 is configured such that, for example, a number of heat transfer plates (plates) are stacked and heat source water and two refrigerants alternately flow between the heat transfer plates and the heat transfer plates to exchange heat with each other. A plate heat exchanger is used. The air-conditioning air is cooled or heated by the air supply side air heat exchanger 12 of this water-cooled heat pump, and the cooling operation and the heating operation can be switched freely to supply air to each zone for air conditioning.

  When performing cooling operation with this water-cooled heat pump type air conditioner 3, the high-pressure gas pipe side on-off valve 23a on the refrigerant inlet / outlet of the heat source side water heat exchanger 14 is opened and the low-pressure gas pipe on-off valve 23b is closed, The on-off valve 23a on the high-pressure gas pipe side of the refrigerant inlet / outlet of the two supply-side air heat exchangers 12 is closed, the on-off valve 23b on the low-pressure gas pipe side is opened, and the on-off valves 24 and 25 are opened. As a result, the refrigerant flows from the compressor 19 to the heat source side water heat exchanger 14 in the high pressure gas state, condenses and flows to the expansion valve 20 in the high pressure liquid state, and is decompressed to one of the air supply side air heat in the low pressure liquid state. The flow is divided into the exchanger 12 and the other air supply side air heat exchanger 12, and each of them is evaporated and merged in a low-pressure gas state to return to the compressor 19, and this cycle is repeated. In this way, the supply air air heat exchanger 12 cools the supply air and performs the cooling operation. When only one of the supply air air heat exchangers 12 performs the cooling operation, the operation side on-off valve is operated. 24 is opened and the on-off valve 24 on the stop side is closed.

  Next, when heating operation is performed, two supply-side air is formed by closing one high-pressure gas pipe side opening / closing valve 23a and opening the low-pressure gas pipe side opening / closing valve 23b at the refrigerant inlet / outlet of the heat source side water heat exchanger 14. The on / off valve 23a on the high pressure gas pipe side of the refrigerant inlet / outlet of the heat exchanger 12 is opened, the on / off valve 23b on the low pressure gas pipe side is closed, and the on / off valves 24 and 25 are opened. As a result, the refrigerant is diverted from the compressor 19 to the one air supply side air heat exchanger 12 and the other air supply side air heat exchanger 12 in the high pressure gas state, and condenses and expands by condensing in the high pressure liquid state. It flows to the valve 20, is decompressed and flows to the heat source side water heat exchanger 14 in the low pressure liquid state, evaporates and returns to the compressor 19 in the low pressure gas state, and this cycle is repeated. In this way, the supply air air heat exchanger 12 heats the supply air to perform the heating operation, but when only one supply air air heat exchanger 12 performs the heating operation, the operation side on-off valve 24 is opened and the on-off valve 24 on the stop side 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, the on-off valve 23a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of the heat source side water heat exchanger 14 Open and close the open / close valve 23b on the low pressure gas pipe side, open the open / close valve 23a on the high pressure gas pipe side of the refrigerant inlet / outlet of one supply side air heat exchanger 12, and open / close valve 23b on the low pressure gas pipe side Is closed, one open / close valve 23a on the high pressure gas pipe side of the refrigerant inlet / outlet of the other air supply side air heat exchanger 12 is closed, and the open / close valve 23b on the low pressure gas pipe side is opened, and the open / close valves 24 and 25 are opened. To. As a result, the refrigerant is split from the compressor 19 into the heat source side water heat exchanger 14 and one of the air supply side air heat exchangers 12 in a high pressure gas state, condensed and joined in the high pressure liquid state to the expansion valve 20. Flow, depressurize and flow to the other air supply side air heat exchanger 12 in the low pressure liquid state, evaporate and return to the compressor 19 in the low pressure gas state, and repeat this cycle. In this way, one of the air supply side air heat exchangers 12 heats the air for supply air to perform a heating operation, and the other air supply side air heat exchanger 12 cools the air for supply air and cools it. Do the driving.

  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, the on-off valve 23a on the one high-pressure gas pipe side of the refrigerant inlet / outlet of the heat source side water heat exchanger 14 Is closed and the open / close valve 23b on the low-pressure gas pipe side is opened, the open / close valve 23a on the high-pressure gas pipe side of the refrigerant inlet / outlet of the one air supply side air heat exchanger 12 is opened, and the open / close valve 23b on the low-pressure gas pipe side Is closed, one open / close valve 23a on the high pressure gas pipe side of the refrigerant inlet / outlet of the other air supply side air heat exchanger 12 is closed, and the open / close valve 23b on the low pressure gas pipe side is opened, and the open / close valves 24 and 25 are opened. To. Thus, the refrigerant flows from the compressor 19 to the one air supply side air heat exchanger 12 in the high pressure gas state, condenses and flows to the expansion valve 20 in the high pressure liquid state, and decompresses to heat source side water heat in the low pressure liquid state. The flow is divided into the exchanger 14 and the other air supply side air heat exchanger 12, and each of them is evaporated and merged in a low-pressure gas state to return to the compressor 19, and this cycle is repeated. In this way, one of the air supply side air heat exchangers 12 heats the air for supply air to perform a heating operation, and the other air supply side air heat exchanger 12 cools the air for supply air and cools it. Do the driving. Further, when the heating load and the cooling load are balanced in the cooling and heating simultaneous operation, by closing the on-off valve 25, the cooling and heating simultaneous operation can be performed without using the heat source side water heat exchanger 14, thereby saving energy.

  The number of the supply air air heat exchanger 12, the on-off valves 24, 23a, 23b, the third and fourth check valves 22a, 22b can be increased or decreased, and the on-off valve 25 can be omitted. One of the refrigerant inlets and outlets of the air supply side air heat exchanger 12 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. Or one of the refrigerant inlets and outlets of the heat source side water heat exchanger 14 is branched and connected to the high pressure gas pipe D and the low pressure gas pipe C via a three-way valve to connect the high pressure gas pipe D and the low pressure gas pipe C to each other. You may connect so that switching is possible. Similarly, the other refrigerant inlet / outlet of the air supply side air heat exchanger 12 is branched and connected to the high pressure liquid pipe B and the low pressure liquid pipe A via a three-way valve, and switched to the high pressure liquid pipe B and the low pressure liquid pipe A. The other side of the refrigerant inlet / outlet of the heat source side water heat exchanger 14 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 are connected. May be connected to be switchable.

  FIG. 4 shows a second embodiment of the present invention. This water-cooled heat pump type ground heat-use air-conditioning system is a water-cooled heat pump type that divides the water into the water tank 1 and supplies the air to a plurality of zones individually for controllable air volume. When the heat source water is circulated through the air conditioner 3 and the underground heat exchanger 9 that adjusts the water temperature by underground heat, and the water temperature adjusted by the underground heat exchanger 9 is outside a predetermined range. An auxiliary heat source machine 5 for adjusting the water temperature of the water tank 1 is provided. The heat source water is sent in the direction of the arrow so that the flow rate can be adjusted by a water pump, and after heat exchange is performed in the heat source side water heat exchanger 14 of the water-cooled heat pump type air conditioner 3, the water temperature is adjusted in the underground heat exchanger 9. Return to the water tank 1 and circulate them. As the auxiliary heat source device 5, various devices that can be freely heated and cooled such as a boiler, a chiller, an electric heater, and a solar water heater can be used. When the water temperature adjusted by the underground heat exchanger 9 is lower than a predetermined water temperature, the auxiliary heat source device 5 is assisted. The heat source device 5 is heated and adjusted within a predetermined range, so that the heat source water can be prevented from freezing and the use of an antifreeze liquid can be avoided. Since the water-cooled heat pump type air conditioner 3 and the underground heat exchanger 9 are the same as those in the above embodiment, the description is omitted.

  FIG. 5 shows a third embodiment of the present invention. This water-cooled heat pump type geothermal heat-use air conditioning system supplies water to the first and second water tanks 1a and 1b and from the first water tank 1a to the second water tank 1b. A heat source water circuit 2 to be sent, a water-cooled heat pump air conditioner 3 through which the water of the heat source water circuit 2 is passed and the air is diverted and individually supplied to a plurality of zones so that the air volume can be controlled, and a second water tank 1b And a geothermal heat exchange water channel 4 for controlling the water temperature by geothermal heat and supplying water to the first water tank 1a in a flow-adjustable manner. The second water tank 1b and the first water tank 1a are communicated by a bypass water channel 8 and this bypass water channel 8 is provided with an on-off valve 10 and an auxiliary heat source device 5 for adjusting the water temperature of the first water tank 1a when the water temperature adjusted in the geothermal exchange channel 4 is outside a predetermined range. Since the water-cooled heat pump type air conditioner 3, the underground heat exchanger 9, and the auxiliary heat source unit 5 are the same as those in the above embodiment, the description thereof is omitted.

  The heat source water circuit 2 includes a forward pipe 2a, a return pipe 2b, and a water pump 6. The first water tank 1a and the water-cooled heat pump air conditioner 3 are connected to the second water tank 1b and the water-cooled heat pump air conditioner via the forward pipe 2a. 3 is made to communicate freely through the return pipe 2b. The heat source water is sent from the first water tank 1a in the direction of the arrow so that the flow rate can be adjusted by the water pump 6, enters the air conditioner 3 from the forward pipe 2a, is heat-exchanged by the water-cooled heat pump, and then goes out to the return pipe 2b. It goes out to the 2nd water tank 1b. The geothermal exchange water channel 4 includes a forward pipe 4a, a return pipe 4b, a water pump 7, and a ground heat exchanger 9, and the second water tank 1b and the ground heat exchanger 9 are connected to the first water tank via the forward pipe 4a. 1a and the underground heat exchanger 9 are communicated freely through the return pipe 4b. The heat source water is sent from the second water tank 1b in the direction of the arrow so that the flow rate can be adjusted by the water pump 7, enters the underground heat exchanger 9 from the forward pipe 4a, and is exchanged by underground heat. It goes out to 4b and goes out to the 1st water tank 1a.

  For example, in the normal operation of the air conditioner, the on-off valve 10 is closed to circulate the water in the first and second water tanks 1a, 1b between the heat source water circuit 2 and the geothermal exchange water channel 4. If the heat source water is circulated only between the first and second water tanks 1a, 1b and the heat source water circuit 2 according to the load condition of the air conditioner operation, the water supply pump 7 is stopped and the on-off valve 10 is opened. Well, to circulate the heat source water only between the water tanks 1a, 1b and the geothermal exchange water channel 4 as in the case of warming up to bring the heat source water into a predetermined water temperature range before operating the air conditioner, the water pump 6 is stopped. Thus, it is sufficient to open the on-off valve 10 and useless transport power is not required.

  In each of the above-described embodiments, the structure of the water-cooled heat pump type air conditioner 3 can be freely changed, and the number of the air supply side air passages 15 can be freely increased or decreased.

1st Example of a water-cooled heat pump type ground heat utilization air conditioning system. The front view of a water cooling heat pump type air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS FIG. The 2nd Example of a water-cooling heat pump type underground heat utilization air-conditioning system. 3rd Example of a water-cooled heat pump type underground heat utilization air-conditioning system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 1a 1st water tank 1b 2nd water tank 2 Heat source water circuit 3 Water-cooled heat pump type air conditioner 4 Geothermal exchange water channel 5 Auxiliary heat source device 8 Bypass channel 9 Ground heat exchanger 10 On-off valve 11 Casing 12 Supply side air heat exchanger 14 Heat source side water heat exchanger 15 Supply air side air passage 19 Compressor 20 Expansion valve A Low pressure liquid pipe B High pressure liquid pipe C Low pressure gas pipe D High pressure gas pipe

Claims (3)

First and second water tanks (1a, 1b), a heat source water circuit (2) for sending water from the first water tank (1a) to the second water tank (1b), and water in the heat source water circuit (2) And a water-cooled heat pump air conditioner (3) for supplying air to each of the plurality of zones for individually controlling the air volume, and from the second water tank (1b) to the first water tank (1a). A geothermal exchange water channel (4) that feeds water with adjustable flow rate and adjusts the water temperature by geothermal heat, and communicates the second water tank (1b) and the first water tank (1a) with a bypass water channel (8). In addition , a water-cooled heat pump type underground heat-use air conditioning system characterized in that an open / close valve (10) is provided in the bypass water channel (8) . The water-cooled heat pump type ground heat utilization according to claim 1, further comprising an auxiliary heat source device (5) for adjusting the water temperature of the first water tank (1a) when the water temperature adjusted in the geothermal exchange channel (4) is outside a predetermined range. Air conditioning system. A plurality of air supply side air passages (15) are provided in the casing (11) of the water-cooled heat pump air conditioner (3), and refrigerant evaporation / refrigerant condensation switching is individually performed for each air supply side air passage (15). A free air supply side air heat exchanger (12) is provided, and the water-cooled heat pump of the water-cooled heat pump type air conditioner (3) includes a heat-source-side water heat exchanger (14) for performing an evaporation process and a condensation process of the circulating refrigerant, and a plurality of , A compressor (19) for compressing the circulating refrigerant, an expansion valve (20) for expanding the circulating refrigerant, a low-pressure 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 (19) is connected to the high-pressure gas pipe (D), and the compressor (19) A refrigerant inlet is connected to the low-pressure gas pipe (C), and the heat source side water heat exchanger (14 One of the refrigerant inlets and outlets is switchably connected to the high pressure gas pipe (D) and the low pressure gas pipe (C), and the other refrigerant inlet and outlet of the heat source side water heat exchanger (14) is connected to the high pressure liquid pipe. (B) and the low pressure liquid pipe (A) are switchably connected, and one of the refrigerant inlets and outlets of each of the air supply side air heat exchangers (12) is connected to the high pressure gas pipe (D) and the low pressure gas pipe ( C), and the other refrigerant inlet / outlet of each air supply side air heat exchanger (12) is switchably connected to the high pressure liquid pipe (B) and the low pressure liquid pipe (A), The water-cooled heat pump type underground heat utilization air conditioning system according to claim 1 or 2, wherein the high-pressure liquid pipe (B) and the low-pressure liquid pipe (A) are connected via the expansion valve (20) .

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