JP2008170044A - Phase change refrigerant circulation unit and air conditioning system - Google Patents

Abstract

A phase change refrigerant circulation unit that prevents pump cavitation, enables smooth and stable refrigerant circulation during both cooling and heating, and enables stable refrigerant circulation even when heating is stopped or restarted. And providing an air conditioning system.
A pump unit 1 according to the present invention circulates a phase change refrigerant in an air conditioning system having a cold / hot water side heat exchanger 2 and an indoor unit 3, and includes a liquid receiver 12, a pump 11, and a receiver. It has flow paths 15, 16 connected to the inlet of the liquid device 12, and flow paths 17, 18 connected to the outlet of the pump 11, and an open / close valve 21 and a check valve 22 are arranged in the flow path 15, An opening / closing valve 24 and a check valve 23 are disposed in the flow path 16, an opening / closing valve 26 and a check valve 25 are disposed in the flow path 17, and an opening / closing valve 27 is disposed in the flow path 18.
[Selection] Figure 1

Description

  The present invention relates to a phase change refrigerant circulation unit used in an air conditioning facility in a building and an air conditioning system using the phase change refrigerant circulation unit. More specifically, the present invention relates to a phase change refrigerant circulation unit and an air conditioning system including a pump for circulating phase change refrigerant, which is used in an air conditioning facility using cold / hot water on the primary side and phase change refrigerant on the secondary side. It is.

  Conventionally, air conditioning in buildings has been performed by circulating heat exchange media such as water and phase change refrigerant to exchange heat with room air. Here, air-conditioning equipment for multi-storey buildings is greatly affected by gravity with respect to vertical circulation. Therefore, the present applicant has proposed a cooling / heating facility using a water circulation circuit using water in the vertical direction and a refrigerant circulation circuit using a gas-liquid phase change refrigerant in the horizontal direction (see Patent Document 1). In this way, the influence of gravity in the refrigerant circuit can be avoided.

  In such an air conditioning system, cold water or hot water is circulated in a water circulation circuit that is a primary heat transfer path, and heat exchange is performed with a gas-liquid phase change refrigerant. In the secondary heat transfer path, the gas-liquid phase change refrigerant is circulated to exchange heat with room air in the indoor unit for air conditioning. In order to realize smooth refrigerant circulation in the secondary heat transfer path, it is important to reliably supply liquid phase refrigerant to the pump in the secondary transfer path without interruption. For this reason, it is considered preferable to arrange the heat exchanger near the downstream side of the heat exchanger acting as a condenser.

  However, in the refrigerant circulation circuit, the refrigerant circulation direction is opposite between cooling and heating, and the heat exchanger acting as a condenser is different. That is, the cold / hot water side heat exchanger acts as a condenser during cooling, and the indoor unit acts as a condenser during heating. These are generally arranged at a great distance, but it is not realistic to provide pumps for cooling and heating. For this reason, as shown in FIGS. 8 and 9, a pump is arranged at a position approximately halfway between the cold / hot water side heat exchanger and the indoor unit, and the circulation direction of the refrigerant is switched by four on-off valves. It was.

  In the conventional air conditioning equipment shown in these drawings, a refrigerant gas pipe 103 and refrigerant liquid pipes 104 and 105 are connected to a cold / hot water side heat exchanger 101 and an indoor unit 102. A pump 106 is provided between the refrigerant liquid pipes 104 and 105. A liquid receiver 107 is provided upstream of the pump 106, and four on-off valves 108, 109, 110, and 111 that connect these to the refrigerant liquid pipes 104 and 105 are provided. A cold / hot water pipe is connected to the cold / hot water side heat exchanger 101 to supply cold water or hot water.

  Here, FIG. 8 shows a state during heating operation, and FIG. 9 shows a state during cooling operation. In these drawings, among the on-off valves 108 to 111, those that are in an open state are outlined in white, those that are in a closed state are black, and closed channels are indicated by broken lines. Also, the white arrow in the figure indicates the direction of refrigerant circulation.

In addition, the on-off valve used in such a refrigerant circulation circuit needs to be of a size that can ensure the refrigerant flow rate. Therefore, a pilot valve is generally used for reasons such as energy required for opening and closing and pressure resistance. A normally closed solenoid valve of the pilot valve type can be closed reliably when the pressure on the input side is higher than that on the output side, but leakage cannot be completely prevented if the pressure relationship is reversed. Therefore, each on-off valve is arranged in a direction that can reliably open and close the original flow direction of the refrigerant at that location. That is, the leakage direction of the closed on-off valve is opposite to the original flow direction of the refrigerant at that location. In each figure, the leak direction is indicated by a dashed arrow below the closed on-off valve.
Japanese Patent No. 3680043

  However, in the above-described conventional equipment, the refrigerant may be heated and vaporized in the refrigerant liquid pipe 104 by the ambient air between the cold / hot water side heat exchanger 101 and the pump 106 during cooling. In that case, since gas is mixed into the suction side of the pump 106 and cavitation occurs, the circulation performance of the pump 106 is deteriorated. Further, at the time of heating, it is necessary to prepare an amount of liquid phase refrigerant that satisfies the refrigerant liquid pipe 104 from the pump 106 to the cold / hot water side heat exchanger 101. For this reason, there is a problem that a large-capacity liquid receiver 107 is required.

  Furthermore, after the heating is stopped such as after the end of winter, the temperature around the indoor unit 102 may decrease and become lower than the liquid receiver 107. In this case, the refrigerant pressure on the liquid receiver 107 side becomes higher than the indoor unit 102 side, and the liquid-phase refrigerant in the liquid receiver 107 leaks the closed electromagnetic valve 109 to the indoor unit 102 side. There is a risk of spillage. Further, if the supply of hot water to the cold / hot water side heat exchanger 101 is stopped, the liquid-phase refrigerant leaks through the closed electromagnetic valve 108 and passes through the cold / hot water side heat exchanger 101 to the indoor unit. There is a risk of flowing out to the 102 side. If the amount of the liquid-phase refrigerant in the liquid receiver 107 decreases due to these leaks, there is a problem that the pump 106 cannot be operated normally at the start of the next heating.

  In addition, the temperature of the indoor unit 102, the refrigerant gas pipe 103, and the like may decrease after the heating stop in winter, and the refrigerant may be liquefied therein. Therefore, at the start of the heating operation in the morning in winter, the on-off valve 110 is once opened, and the liquid refrigerant is sent to the cold / hot water side heat exchanger 101 by the pump 106. Thereafter, the on-off valve 110 is closed and only the on-off valve 109 is opened. The pump 106 supplies hot water to the cold / hot water side heat exchanger 101 in a stopped state. As a result, the cold / hot water side heat exchanger 101 is set to the highest pressure, a pressure difference is created in the order of the refrigerant gas pipe 103, the indoor unit 102, the refrigerant liquid pipe 105, and the liquid receiver 107, and the intermediate refrigerant is transferred to the liquid receiver 107. The process of collecting is performed. At this time, since the leakage direction of the closed on-off valve 110 is rightward in FIG. 8, the refrigerant may leak from the cold / hot water side heat exchanger 101 to the on-off valve 110 and flow into the outlet side of the pump 106. It was.

  The present invention has been made to solve the above-described problems of the prior art. In other words, the problem is that, even when cavitation occurs on the suction side of the pump, it is possible to smoothly and stably circulate the refrigerant both during cooling and during heating, and also when heating is stopped or restarted. An object is to provide a phase change refrigerant circulation unit and an air conditioning system capable of refrigerant circulation.

  In order to solve this problem, the phase change refrigerant circulation unit of the present invention circulates a phase change refrigerant in an air-conditioning system having a primary heat exchanger and a secondary heat exchanger. A liquid receiver that contains the change refrigerant, a pump that sends out the phase change refrigerant in the liquid phase of the liquid receiver, first and second inflow passages connected to the inlet of the liquid receiver, and an outlet of the pump A first inflow channel and a first outflow channel are connected to the primary heat exchanger, and the second inflow channel and the second outflow channel are secondary. A phase change refrigerant circulation unit connected to the heat exchanger, the first outflow on-off valve arranged in the first outflow passage, the second outflow on-off valve arranged in the second outflow passage, It is arranged in the inflow channel and allows flow in both directions in the open state and from the primary heat exchanger in the closed state. The first inflow on-off valve that does not allow leakage to the vessel and allows leakage from the receiver to the primary heat exchanger, and the first inflow passage, and receives the liquid from the primary heat exchanger. Is arranged in the first check valve and the second inflow passage that allow the flow to the vessel and block the flow from the receiver to the primary heat exchanger, and allows the flow in both directions in the open state. In the closed state, a second inflow opening / closing valve that does not allow leakage from the secondary heat exchanger to the liquid receiver and permits leakage from the liquid receiver to the secondary heat exchanger, and a second inflow channel And a second check valve that allows the flow from the secondary heat exchanger to the liquid receiver and prevents the flow from the liquid receiver to the secondary heat exchanger.

  According to the phase change refrigerant circulation unit of the present invention, the liquid phase change refrigerant flowing into the inlet of the receiver from the first and second inflow passages is sent to the first and second outflow passages by the pump. Is done. The first inflow channel and the first outflow channel are connected to the primary heat exchanger, and the second inflow channel and the second outflow channel are connected to the secondary heat exchanger. The phase change of the phase change refrigerant is performed by the exchanger, and air conditioning is performed. Here, the first outflow channel is opened / closed by the first outflow on / off valve, and the second outflow channel is opened / closed by the second outflow on / off valve. The first inflow channel is opened and closed by the first inflow on / off valve, and the second inflow channel is opened and closed by the second inflow on / off valve. These first inflow on-off valve and second inflow on-off valve allow leakage from the receiver to the primary heat exchanger or the secondary heat exchanger in the closed state. However, in the present invention, these leak-wise flows are blocked by the first check valve and the second check valve. Therefore, the phase change refrigerant is prevented from flowing out of the receiver.

  Furthermore, in the present invention, it is desirable that the first check valve is disposed between the first inflow on-off valve and the liquid receiver, and the second check valve includes the second inflow on-off valve, the liquid receiver, It is desirable to arrange | position between. If it becomes like this, the outflow pressure from a liquid receiver will be blocked | prevented by each check valve, and it will not be added to each inflow on-off valve.

  The phase change refrigerant circulation unit of the present invention circulates a phase change refrigerant in an air conditioning system having a primary heat exchanger and a secondary heat exchanger, and stores a liquid phase change refrigerant. A pump for delivering a phase change refrigerant in the liquid phase of the liquid receiver, first and second inflow passages connected to the inlet of the liquid receiver, and first and second outflows connected to the outlet of the pump A phase in which the first inflow channel and the first outflow channel are connected to the primary heat exchanger, and the second inflow channel and the second outflow channel are connected to the secondary heat exchanger. A change refrigerant circulation unit, a first inflow opening / closing valve disposed in the first inflow passage, a second inflow opening / closing valve disposed in the second inflow passage, and a second inflow passage disposed in the second outflow passage. 2 Outflow on-off valve and the first outflow passage, both permit flow in the open state and pump in the closed state Are disposed in the first outflow on / off valve that does not allow leakage to the primary heat exchanger and allows leakage from the primary heat exchanger to the pump, and the first heat flow from the pump. A third check valve that allows flow to the exchanger and blocks flow from the primary heat exchanger to the pump.

  According to the phase change refrigerant circulation unit of the present invention, since the first outflow passage is provided with the first outflow on-off valve and the third check valve, even when the pump is stopped, 1 The flow from the secondary heat exchanger to the pump is blocked. Therefore, there is no possibility that the refrigerant flows from the primary heat exchanger to the pump even when the system is stopped.

  Furthermore, in the present invention, it is desirable that the third check valve is disposed between the first outflow on-off valve and the primary heat exchanger. In this case, the flow from the primary heat exchanger is blocked by the third check valve and is not added to the first outflow on / off valve.

  The phase change refrigerant circulation unit of the present invention circulates a phase change refrigerant in an air conditioning system having a primary heat exchanger and a secondary heat exchanger, and stores a liquid phase change refrigerant. A pump for delivering a phase change refrigerant in the liquid phase of the liquid receiver, first and second inflow passages connected to the inlet of the liquid receiver, and first and second outflows connected to the outlet of the pump A phase in which the first inflow channel and the first outflow channel are connected to the primary heat exchanger, and the second inflow channel and the second outflow channel are connected to the secondary heat exchanger. A change refrigerant circulation unit, a first inflow opening / closing valve disposed in the first inflow passage, a second inflow opening / closing valve disposed in the second inflow passage, and a first inflow passage disposed in the first outflow passage. 1 outflow on-off valve, a second outflow on-off valve arranged in the second outflow passage, a circulation path connecting the inlet of the liquid receiver and the outlet of the pump, A circulation path on-off valve disposed in the circulation path, provided in the circulation path, and has an air heat exchanger for exchanging heat between the air which is not heated and the phase change coolant.

  According to the phase change refrigerant circulation unit of the present invention, in addition to the circulation of the phase change refrigerant via the primary heat exchanger and the secondary heat exchanger, the circulation can be made via the air heat exchanger and the circulation path. it can. Thereby, the state of a liquid receiver can be changed temporarily.

  Furthermore, in the present invention, it is desirable that the air heat exchanger be installed in an unheated space. It is desirable to install a liquid level sensor in the receiver. And a circuit controller for closing the circuit opening / closing valve during normal operation and opening the circuit opening / closing valve when the liquid level sensor detects a drop in the liquid level during the heating operation. Is desirable. If it becomes like this, if the liquid level fall of a liquid receiver is detected, the refrigerant | coolant will be circulated through a circulation path. Accordingly, the liquid level of the liquid receiver can be restored by temporarily changing the state of the liquid receiver.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, The first and second inflow passages connected to the inlet of the liquid device, and the first and second outflow passages connected to the outlet of the pump, the first inflow passage and the first outflow passage being An air conditioning system connected to a primary heat exchanger and having a second inflow channel and a second outflow channel connected to a secondary heat exchanger, wherein the first outflow on-off valve is disposed in the first outflow channel And a second outflow on-off valve disposed in the second outflow passage and a first inflow passage, and allows flow in both directions in the open state and from the primary heat exchanger in the closed state. A first inflow on-off valve that does not allow leakage to the receiver and allows leakage from the receiver to the primary heat exchanger, and a first inflow passage; The first check valve that allows the flow from the primary heat exchanger to the liquid receiver and prevents the flow from the liquid receiver to the primary heat exchanger, and the second check valve, In the open state, the flow is allowed in both directions, and in the closed state, the second inflow does not allow leakage from the secondary heat exchanger to the receiver, but allows leakage from the receiver to the secondary heat exchanger. A second check that is arranged in the on-off valve and the second inflow channel, allows flow from the secondary heat exchanger to the liquid receiver, and blocks flow from the liquid receiver to the secondary heat exchanger. Also extends to air conditioning systems with valves.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, The first and second inflow passages connected to the inlet of the liquid device, and the first and second outflow passages connected to the outlet of the pump, the first inflow passage and the first outflow passage being An air conditioning system connected to a primary heat exchanger and having a second inflow channel and a second outflow channel connected to a secondary heat exchanger, wherein the first inflow on / off valve is disposed in the first inflow channel And a second inflow on / off valve disposed in the second inflow channel, a second outflow on / off valve disposed in the second outflow channel, and a first outflow channel, and in a bidirectional state in the open state In the closed state, the first flow that allows leakage from the primary heat exchanger to the pump and does not allow leakage from the pump to the primary heat exchanger. An on-off valve and a third check valve that is disposed in the first outflow passage and that allows the flow from the pump to the primary heat exchanger and prevents the flow from the primary heat exchanger to the pump. It extends to air conditioning systems.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, The first and second inflow passages connected to the inlet of the liquid device, and the first and second outflow passages connected to the outlet of the pump, the first inflow passage and the first outflow passage being An air conditioning system connected to a primary heat exchanger and having a second inflow channel and a second outflow channel connected to a secondary heat exchanger, wherein the first inflow on / off valve is disposed in the first inflow channel A second inflow opening / closing valve disposed in the second inflow passage, a first outflow opening / closing valve disposed in the first outflow passage, a second outflow opening / closing valve disposed in the second outflow passage, A circulation path connecting the inlet of the liquid receiver and the outlet of the pump, a circulation path opening / closing valve disposed in the circulation path, and a phase change refrigerant and unheated air provided in the circulation path Also extends to an air conditioning system having an air heat exchanger for exchanging heat between.

  The air conditioning system of the present invention includes a primary heat exchanger, a secondary heat exchanger, a liquid receiver that stores a liquid phase change refrigerant, and a pump that sends out the liquid phase change refrigerant of the liquid receiver. And first and second inflow channels connected to the inlet of the liquid receiver, and first and second outflow channels connected to the outlet of the pump, the first inflow channel and the first outflow channel An air conditioning system in which a flow path is connected to a primary heat exchanger, and a second inflow path and a second outflow path are connected to a secondary heat exchanger, wherein the first inflow path is disposed in the first inflow path An inflow on-off valve, a second inflow on-off valve disposed in the second inflow passage, a first outflow on-off valve disposed in the first outflow passage, and a second outflow on-off disposed in the second outflow passage The volume of the pipe from the outlet of the pump to the inlet of the primary heat exchanger is smaller than the volume of the portion through which the phase change refrigerant passes in the secondary heat exchanger. It is the casting.

  According to the air conditioning system of the present invention, the volume of the pipe from the outlet of the pump to the inlet of the primary heat exchanger is made smaller than the capacity of the phase change refrigerant that can be accumulated in the secondary heat exchanger. Yes. Furthermore, it is desirable to make it smaller than the capacity of the liquid phase change refrigerant accumulated in the secondary heat exchanger. Normally, not only liquid phase change refrigerant but also gas phase change refrigerant is present in the secondary heat exchanger. For example, the liquid phase change refrigerant often occupies about 50% of the volume of the portion through which the phase change refrigerant passes. In that case, the volume of the pipe from the outlet of the pump to the inlet of the primary heat exchanger may be smaller than 50% of the volume of the portion through which the phase change refrigerant passes in the secondary heat exchanger. In this way, there is no possibility that the phase change refrigerant in the gas phase is mixed into the inlet side of the pump. In addition, when there are a plurality of secondary heat exchangers, the volume may be smaller than the smallest one of them.

  According to the phase change refrigerant circulation unit and the air conditioning system of the present invention, even when cavitation occurs on the suction side of the pump, the refrigerant can be circulated smoothly and stably during both cooling and heating, and when heating is stopped. Stable refrigerant circulation is possible even when restarting.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a pump unit used in a cooling / heating facility using cold / hot water on the primary side and phase change refrigerant (hereinafter simply referred to as refrigerant) on the secondary side. In this embodiment, the pump unit corresponds to a phase change refrigerant circulation unit, which includes a primary side heat exchanger (here, a cold / hot water side heat exchanger) and a secondary side heat exchanger (here, an indoor unit). ) Is equivalent to an air conditioning system.

  In an air conditioning system using cold / hot water on the primary side and refrigerant on the secondary side, two types of heat exchangers, a cold / hot water side heat exchanger 2 and an indoor unit 3, are used as shown in FIG. A cold / hot water pipe 4 and a refrigerant pipe 5 are passed through the cold / hot water side heat exchanger 2, and heat exchange is performed between the cold / hot water flowing through these and the refrigerant. And at the time of cooling, cold water flows into the cold / hot water piping 4, and in the cold / hot water side heat exchanger 2, a refrigerant changes phase from a gaseous phase to a liquid phase. In addition, hot water is caused to flow through the cold / hot water pipe 4 during heating, and in the cold / hot water side heat exchanger 2, the refrigerant changes phase from a liquid phase to a vapor phase. The cold / hot water side heat exchanger 2 corresponds to a primary heat exchanger, and the indoor unit 3 corresponds to a secondary heat exchanger.

  The indoor unit 3 is connected to a refrigerant gas pipe 6 through which a gas-phase refrigerant flows and a refrigerant liquid pipe 7 through which a liquid-phase refrigerant flows. At the time of cooling, the liquid-phase refrigerant flowing from the refrigerant liquid pipe 7 takes heat from the indoor air in the indoor unit 3, changes the phase to the gas phase, and flows out to the refrigerant gas pipe 6. During heating, the gas-phase refrigerant flowing from the refrigerant gas pipe 6 is deprived of heat by the indoor air in the indoor unit 3, changes to the liquid phase, and flows out to the refrigerant liquid pipe 7.

  The pump unit 1 of this embodiment has a pump 11 and a liquid receiver 12 upstream thereof, and is unitized by incorporating a plurality of valves and flow paths. As shown in FIG. 1, this is connected to the refrigerant liquid pipe 7 through the connection ports 13 and 14, and liquid phase refrigerant is input and output therefrom. The connection port 13 is provided on the cold / hot water side heat exchanger 2 side, and the connection port 14 is provided on the indoor unit 3 side. In the pump unit 1, flow paths 15, 16, 17, 18 and a circulation path 19 are provided centering on the pump 11 and the liquid receiver 12.

  The flow path 15 connects the connection port 13 and the inlet of the liquid receiver 12, and an open / close valve 21 and a check valve 22 are arranged in the flow path 15 in that order from the connection port 13 side. The flow path 16 connects the inlet of the liquid receiver 12 and the connection port 14, and a check valve 23 and an opening / closing valve 24 are disposed in the flow path 16 in order from the liquid receiver 12 side. . The flow path 17 connects the connection port 13 and the outlet of the pump 11, and a check valve 25 and an on-off valve 26 are arranged in the flow path 17 in order from the connection port 13 side. The flow path 18 connects the outlet of the pump 11 and the connection port 14, and an open / close valve 27 is disposed in the flow path 18. The direction of each on-off valve and check valve will be described later.

  That is, the flow path 15 corresponds to the first inflow flow path, the flow path 16 corresponds to the second inflow flow path, the on-off valve 21 corresponds to the first inflow on-off valve, and the check valve 22 corresponds to the first check valve. The on-off valve 24 corresponds to a second inflow on-off valve, and the check valve 23 corresponds to a second check valve. The flow path 17 corresponds to the first outflow flow path, the flow path 18 corresponds to the second outflow flow path, the open / close valve 26 corresponds to the first outflow open / close valve, and the check valve 25 corresponds to the third check valve. The on-off valve 27 corresponds to a second outflow on-off valve.

  The circulation path 19 is a flow path that connects the inlet of the liquid receiver 12 and the outlet of the pump 11 and circulates. Each container 29 is arranged. In addition, each flow path 15-18 and the circulation path 19 are merged in the location shown by the black circle in FIG. 1, and are not merged in other intersections. The pump 11 pushes liquid phase refrigerant into the flow paths 17 and 18 or the circulation path 19 as indicated by arrows in the figure.

  The liquid receiver 12 is provided with a liquid level sensor 31 for detecting the liquid level of the stored refrigerant. Further, the pump unit 1 includes a control unit 32 that controls each unit. That is, the control unit 32 controls the opening / closing of the on-off valves 21, 24, 26, 27, 28, the driving / stopping of the pump 11, and the driving / stopping of the air heat exchanger 29. The result is entered.

  Here, the on-off valves 21, 24, 26, 27, and 28 are all normally closed electromagnetic on-off valves of a pilot valve type similar to the conventional one, and generally the directions of the input port and the output port are determined. When the fluid pressure on the input port side is larger than the external pressure on the output port side, the fluid flow from the input port to the output port can be appropriately opened and closed. That is, in this case, there is no leak of the valve in the closed state. However, when reverse pressure is applied, it cannot be reliably closed. In a flow path with higher external pressure on the output port side, leakage from the output port side to the input port side cannot be completely prevented even if the valve is closed. For this reason, each on-off valve is arranged so that the input port faces the high pressure side under normal conditions.

  In this embodiment, during normal cooling and heating, the liquid-phase refrigerant flows into the liquid receiver 12 via the flow path 15 or the flow path 16 and flows out of the pump 11 via the flow path 17 or the flow path 18. Further, in the circulation path 19, the circulation path 19 circulates from the outlet of the pump 11 to the inlet of the liquid receiver 12. Therefore, any on-off valve is arranged in a direction along the flow in this direction. That is, the on-off valves 21, 24, 28 are arranged with the output port on the liquid receiver 12 side. Therefore, in the closed state, leakage in the direction of flowing into the liquid receiver 12 is not allowed. The on-off valves 26 and 27 are arranged with the input port on the pump 11 side. Therefore, the leak in the direction of flowing out from the pump 11 in the closed state is not allowed.

  In this embodiment, the reverse flow is prevented by arranging a check valve on the output port side of each on-off valve. For example, in FIG. 1, the input port of the on-off valve 21 is on the connection port 13 side, and the flow from the connection port 13 to the liquid receiver 12 can be reliably opened and closed by the on-off valve 21. On the other hand, when the liquid receiver 12 side becomes high pressure, the check valve 22 prevents the flow from the liquid receiver 12 toward the on-off valve 21. That is, the check valve 22 allows only the flow in the direction from the on-off valve 21 to the inlet of the liquid receiver 12. In addition, the arrow shown in the lower part of each check valve in FIG. 1 shows the direction in which the flow in the valve is permitted. In addition, at the bottom of each on-off valve, the leak direction of the valve is indicated by a broken line arrow.

  Further, the input port of the on-off valve 24 is on the connection port 14 side, and a check valve 23 is disposed between the on-off valve 24 and the liquid receiver 12. The check valve 23 prevents the flow from the liquid receiver 12 toward the on-off valve 24. Further, the input port of the on-off valve 26 is on the pump 11 side, and a check valve 25 is provided between the on-off valve 26 and the connection port 13. The check valve 25 prevents a flow from the connection port 13 toward the on-off valve 26.

  Next, the arrangement relationship between the pump 11 and the chilled / hot water side heat exchanger 2 when the pump unit 1 is used in a cooling / heating facility as shown in FIG. 1 will be described. The pump unit 1 according to the present embodiment is not disposed at a position intermediate between the cold / hot water side heat exchanger 2 and the indoor unit 3 as in the prior art, but the cold / hot water side heat exchanger 2 that functions as a condenser during cooling. Place in the vicinity of In particular, the pump 11 and the liquid receiver 12 and the cold / hot water side heat exchanger 2 are arranged as close as possible.

  On the other hand, the indoor unit 3 functions as a condenser during heating operation. In this embodiment, the distance between the indoor unit 3 and the pump 11 or the liquid receiver 12 is increased, but it is only necessary that the indoor unit 3 can be reliably liquefied before the inlet of the pump 11. For this purpose, the volume of the pipe between the outlet of the pump 11 and the inlet of the cold / hot water side heat exchanger 2 is reduced. In particular, the volume of the smallest indoor unit 3 is made smaller. More specifically, it is preferable to make the amount smaller than the amount of liquid refrigerant stored in the indoor unit 3. In general, the proportion of the refrigerant in the liquid phase is about 50%, and the amount of the refrigerant in the liquid phase is about half of the total internal volume.

Here, a range P1 indicated by a bold line in FIG. 2 is a pipe from the outlet of the pump 11 to the inlet of the cold / hot water-side heat exchanger 2, and this internal volume is the capacity C1. The range P2 schematically shows piping passing through the indoor unit 3, and about 50% of the internal volume is the capacity C2. And these satisfy the following relationship.
Capacity C1 <capacity C2

  For example, the refrigerant amount in the case of a 28 kW built-in duct type R-407C indoor unit is calculated as follows. The piping for passing the refrigerant of the indoor unit is composed of a plurality of fin tubes, and each fin tube has an outer diameter of 9.5 mm and a wall thickness of 0.8 mm. Therefore, the internal volume per 1 m length is about 0.049 L (liter). In this indoor unit, since 54 fin tubes with a length of 1.55 m are used, the total internal volume is about 4.1 L. Assuming that 50% of the total is occupied by a liquid-phase refrigerant, the capacity C2 is about 0.2L.

  On the other hand, the volume of the pipe from the outlet of the pump 11 to the inlet of the cold / hot water side heat exchanger 2 is obtained by multiplying the inner sectional area of the pipe by the pipe length. For example, when φ6 / 8B is used as the pipe, the inner diameter per meter of length is about 0.228 L because the outer diameter is 19.05 mm and the wall thickness is 1.00 mm. When this is multiplied by the length of the pipe, a capacity C1 is obtained. Therefore, in order to make the pipe capacity C1 smaller than the capacity C2, the length of the pipe should be within about 0.9 m.

  In this way, the amount of the liquid-phase refrigerant accumulated between the outlet of the pump 11 and the inlet of the cold / hot water side heat exchanger 2 is smaller than that of each indoor unit 3. Accordingly, the drainage of liquid on the suction side of the pump 11 is prevented. Therefore, cavitation of the pump 11 is reliably prevented.

  Next, the operation | movement at the time of the air conditioning by the air conditioning equipment which connected the pump unit 1 of this form is demonstrated. First, the heating operation will be described with reference to FIG. In this case, the on-off valves 21, 27, and 28 are closed, and the on-off valve 24 and the on-off valve 26 are opened. Accordingly, the flow paths 16 and 17 are opened, and the flow paths 15 and 18 and the circulation path 19 are closed. In the following figures, open / closed valves are indicated by white symbols, and closed open / close valves are indicated by black symbols. In addition, the communication channel is indicated by a solid line and the closed channel is indicated by a broken line. Note that hot water is supplied to the cold / hot water pipe 4 from the outside during heating.

  When the heating operation is started, the pump 11 is driven, and the liquid-phase refrigerant pushed out by the pump 11 is input to the cold / hot water side heat exchanger 2 through the flow path 17 and the opening / closing valve 26. Furthermore, in the cold / hot water side heat exchanger 2, it receives heat from warm water and is vaporized. The gas-phase refrigerant that has become a gas phase is input to the indoor unit 3 via the refrigerant gas pipe 6. The indoor unit 3 releases heat to the indoor air, and the refrigerant is liquefied. Further, the liquefied refrigerant is input to the pump unit 1 from the connection port 14 via the refrigerant liquid pipe 7. Then, the liquid is returned to the liquid receiver 12 through the flow path 16 and the on-off valve 24 and supplied to the pump 11 again. Note that the open / close valves 21, 27, 28 in the closed state all have high pressure on the input port side, so that leakage does not cause a problem.

  When the refrigerant circulates in this way, in the cold / hot water-side heat exchanger 2, a gas-phase refrigerant having a saturation temperature of about 2 ° C. lower than the temperature of the hot water is generated. Based on the state of the refrigerant in the gas phase, the refrigerant in the refrigerant liquid pipe 7 to the flow path 16 from the indoor unit 3 through the liquid receiver 12 to the inlet of the pump 11 is relatively supercooled. . Therefore, the refrigerant is reliably liquefied between the indoor unit 3 and the liquid receiver 12.

  Therefore, liquid phase refrigerant without cavitation is stably supplied to the inlet side of the pump 11. Thereby, even if the distance between the indoor unit 3 that functions as a condenser during heating and the pump 11 is separated, smooth and stable refrigerant circulation is possible. In addition, if only measures against cavitation of the pump 11 can be achieved to some extent by increasing the size of the liquid receiver 12, it is not preferable because the equipment becomes larger.

  During the heating operation period, when the heating operation is started at the start of the morning, etc., start-up processing is first performed. During the heating operation period, the outside air temperature is low. In particular, the equipment is cooled by cold air at night, and the temperatures of the indoor unit 3 and the refrigerant gas pipe 6 are lowered, and the refrigerant may be liquefied therein. Then, from the state where everything is stopped, the on-off valve 26 is opened, and the liquid refrigerant is sent to the cold / hot water side heat exchanger 2. Thereafter, as shown in FIG. 4, the on-off valve 26 is closed and the on-off valve 24 is opened. And hot water is supplied to the cold / hot water side heat exchanger 2 with the other on-off valves 21, 27, 28 closed. At this time, the pump 11 is also stopped.

  Thereby, the refrigerant | coolant which remained in the cold / hot water side heat exchanger 2 is vaporized, and the pressure in the cold / hot water side heat exchanger 2 rises. As a result, the refrigerant gas pipe 6, the indoor unit 3, the refrigerant liquid pipe 7, and the liquid receiver 12 are reduced in order in the cold / hot water side heat exchanger 2 as the maximum pressure. Due to this pressure difference, the refrigerant on the way flows in the above order and is collected in the liquid receiver 12.

  At this time, since the cold / hot water side heat exchanger 2 has a higher pressure than the flow path 17, the refrigerant in the cold / hot water side heat exchanger 2 tends to flow not only to the refrigerant gas pipe 6 but also to the flow path 17. . However, in this embodiment, since the check valve 25 is disposed in the flow path 17, the check valve 25 prevents the flow from the cold / hot water side heat exchanger 2 toward the outlet of the pump 11. The refrigerant does not flow through the flow path indicated by the broken line in FIG. As a result, the liquid-phase refrigerant is reliably recovered in the liquid receiver 12.

  Next, the processing when the operation is stopped after the end of work during the heating operation period will be described. When the operation is stopped in the air conditioning equipment of this embodiment, the pump 11 is stopped and all on-off valves (on-off valves 21, 24, 26, 27, 28) are closed, and the circulation of the refrigerant is stopped. Here, the outside air temperature is low during the heating operation period, and the temperature in the vicinity of the indoor unit 3 after the heating operation is stopped decreases. On the other hand, the liquid receiver 12 in which the refrigerant is stored is in a state where heat is stored to some extent in the refrigerant, and the temperature does not decrease immediately. For this reason, the receiver 12 may be hotter than the indoor unit 3. In that case, the periphery of the liquid receiver 12 has a higher pressure than the periphery of the indoor unit 3.

  Even if the on-off valve 21 and the on-off valve 24 are closed, the leakage of the refrigerant from the inlet of the liquid receiver 12 cannot be prevented by itself. However, since the pump unit 1 of this embodiment has check valves 22 and 23 as shown in FIG. 5, the refrigerant flows out from the inlet side of the liquid receiver 12 by the check valves 22 and 23. It is blocked. Therefore, even when the liquid receiver 12 has a higher pressure than the indoor unit 3, leakage of the refrigerant through the flow paths 15 and 16 is prevented. That is, the refrigerant flows through the flow path indicated by the solid line in FIG. 5, but the refrigerant does not flow through the flow path indicated by the broken line. As a result, the refrigerant in the liquid receiver 12 does not decrease at night. Therefore, at the start of operation on the next day, a sufficient amount of refrigerant is held in the liquid receiver 12, and the liquid phase refrigerant can be reliably supplied to the pump 11.

  Next, the heating operation process in the extremely cold season will be described. In the extremely cold season, the refrigerant gas pipe 6 and the surroundings of the indoor unit 3 may be extremely cooled despite the heating operation. Then, the gas-phase refrigerant may be liquefied at that portion. When the gas-phase refrigerant is liquefied, the pressure is reduced, and further refrigerant flows into that portion and condenses. If this process is repeated, liquid phase refrigerant accumulates in that part, and a so-called “sleeping” state occurs. Even if the normal operation is continued as it is, the stagnation refrigerant cannot be returned to the liquid receiver 12.

  If it becomes like this, since the refrigerant | coolant amount stored in the liquid receiver 12 will reduce, a liquid level will fall. In this embodiment, since the liquid level sensor 31 is provided in the liquid receiver 12, it can be detected by the control unit 32 when the liquid level falls. When it is detected that a predetermined amount or more of the refrigerant has stagnated and the liquid level has been lowered to a predetermined position, the on-off valve 28 is opened and the fan of the air heat exchanger 29 is opened as shown in FIG. Is activated. The air heat exchanger 29 is disposed at a position where the air heat exchanger 29 is surely at a low temperature as compared with other flow paths during the heating operation period. For example, it is preferably arranged outside the range of the air conditioning equipment. In the case of extremely cold areas, it may be one without a fan.

  If it does in this way, a refrigerant will flow through a channel shown by a solid line in FIG. The refrigerant does not flow through the flow path indicated by the broken line. That is, the refrigerant also flows through the circulation path 19. The refrigerant that has flowed through the circulation path 19 is cooled by the air heat exchanger 29. Accordingly, the refrigerant temperature in the circulation path 19 is lowered, and the pressure in the circulation path 19 is lowered. As a result, the refrigerant temperature in the liquid receiver 12 decreases and the pressure in the liquid receiver 12 decreases. And since the liquid receiver 12 becomes a negative pressure with respect to the refrigerant | coolant liquid pipe | tube 7, the indoor unit 3, and the refrigerant | coolant gas pipe | tube 6, the stagnation refrigerant | coolant is drawn in the liquid receiver 12. FIG. Accordingly, the amount of refrigerant stored in the liquid receiver 12 increases. When the liquid level sensor 31 detects that a predetermined liquid level position has been reached, the on-off valve 28 is closed and the fan of the air heat exchanger 29 is stopped. And normal heating operation should just be continued.

  Next, in the air conditioning equipment using the pump unit 1 of the present embodiment, processing during cooling operation will be described with reference to FIG. At the time of cooling, the on-off valves 24, 26, 28 are closed, and the on-off valves 21, 27 are opened. Accordingly, the flow paths 15 and 18 are opened, and the flow paths 16 and 17 and the circulation path 19 are closed. As in FIG. 3, in FIG. 7, the open / closed valve is indicated by a white symbol, and the closed open / close valve is indicated by a black symbol. A closed flow path is indicated by a broken line. During cooling, cold water is supplied to the cold / hot water pipe 4 from the outside.

  When the cooling operation is started, the liquid-phase refrigerant pushed out from the pump 11 is sent from the flow path 18 and the on-off valve 27 to the refrigerant liquid pipe 7 through the connection port 14. And in the indoor unit 3, it takes heat from indoor air and is vaporized. Further, the gas phase refrigerant that has become a gas phase is input to the cold / hot water side heat exchanger 2 through the refrigerant gas pipe 6, and is condensed by releasing heat into the cold water in the cold / hot water pipe 4. The refrigerant in the liquid phase state is input to the pump unit 1 from the connection port 13. Further, the liquid is returned to the liquid receiver 12 through the flow path 15.

  Here, since the pump 11 and the liquid receiver 12 and the cold / hot water side heat exchanger 2 are arranged close to each other, at the time of cooling, the liquid phase refrigerant condensed in the cold / hot water side heat exchanger 2 is received by the liquid receiver. In the middle of reaching 12, there is almost no pressure loss. Accordingly, the liquid phase state is maintained even in the flow path from the pump 11 to the indoor unit 3. Thus, smooth and stable refrigerant circulation is possible even during cooling operation.

  As described above in detail, according to the pump unit 1 of the present embodiment, the check valve for preventing the backflow is provided in the on-off valve in the flow path. Is prevented. In particular, backflow from the pressure difference is prevented while the equipment is shut down. Further, since the circulation path 19 and the air heat exchanger 29 are provided, the refrigerant that has stagnated in the flow path can be easily recovered. Further, the pump 11 is disposed in the vicinity of the cold / hot water side heat exchanger 2 and the volume of the pipe from the outlet of the pump 11 to the inlet of the cold / hot water side heat exchanger 2 is the smallest among the indoor units 3. The amount of refrigerant in the liquid phase is smaller. Therefore, cavitation is prevented both during heating and during cooling, and a smooth and stable refrigerant circulation can be achieved. Therefore, even when cavitation occurs on the suction side of the pump, it is possible to smoothly and stably circulate the refrigerant both during cooling and heating, and to enable stable refrigerant circulation even when heating is stopped or restarted. It is a facility.

  In addition, since each check valve is provided on the upstream side with respect to the leak direction of the corresponding on-off valve, the flow in the leak direction does not reach each on-off valve. Therefore, no pressure is applied to the output port side of the on-off valve.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, although the cold / hot water pipe 4 is provided on the primary side and the cold / hot water is used as the heat medium, it is not limited to pure water. Any liquid heat medium that can utilize sensible heat may be used. In each figure, only one indoor unit 3 is shown, but the present invention can also be applied to facilities to which a plurality of indoor units 3 are connected.

It is a block diagram which shows schematic structure of the pump unit of this form. It is explanatory drawing which shows the relationship between the indoor unit of a pump unit, and a pump. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of heating. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of heating starting. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of a heating stop. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of heating in an extremely cold season. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of air_conditioning | cooling. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of the heating operation by the conventional air conditioning equipment. It is explanatory drawing which shows the circulation of the refrigerant | coolant at the time of the air_conditionaing | cooling operation by the conventional air conditioning equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump unit 2 Cold / hot water side heat exchanger 3 Indoor unit 11 Pump 12 Receiving device 15, 16, 17, 18 Flow path 19 Circulation path 21,24,26,27,28 Check valve 22,23,25 Check valve 29 Air Heat Exchanger 31 Liquid Level Sensor 32 Control Unit

Claims (10)

A phase change refrigerant is circulated in an air conditioning system having a primary heat exchanger and a secondary heat exchanger, and a liquid receiver that stores the liquid phase change refrigerant, and a liquid phase of the liquid receiver. A pump for delivering a change refrigerant; first and second inflow passages connected to an inlet of the receiver; and first and second outflow passages connected to an outlet of the pump; In a phase change refrigerant circulation unit in which a first inflow channel and a first outflow channel are connected to a primary heat exchanger, and the second inflow channel and the second outflow channel are connected to a secondary heat exchanger,
A first outflow on-off valve disposed in the first outflow passage;
A second outflow on-off valve disposed in the second outflow channel;
Disposed in the first inflow channel,
When open, it allows flow in both directions,
In a closed state, a first inflow on-off valve that does not allow leakage from the primary heat exchanger to the receiver and permits leakage from the receiver to the primary heat exchanger;
Disposed in the first inflow channel,
Allowing the flow from the primary heat exchanger to the receiver,
A first check valve that blocks flow from the receiver to the primary heat exchanger;
Disposed in the second inflow channel,
When open, it allows flow in both directions,
In the closed state, a second inflow on-off valve that does not allow leakage from the secondary heat exchanger to the liquid receiver and permits leakage from the liquid receiver to the secondary heat exchanger;
Disposed in the second inflow channel,
Allowing flow from the secondary heat exchanger to the receiver,
A phase change refrigerant circulation unit comprising: a second check valve for preventing flow from the liquid receiver to the secondary heat exchanger. The phase change refrigerant circulation unit according to claim 1,
The first check valve is disposed between the first inflow on-off valve and the liquid receiver;
The phase change refrigerant circulation unit, wherein the second check valve is disposed between the second inflow opening / closing valve and the liquid receiver. A phase change refrigerant is circulated in an air conditioning system having a primary heat exchanger and a secondary heat exchanger, and a liquid receiver that stores the liquid phase change refrigerant, and a liquid phase of the liquid receiver. A pump for delivering a change refrigerant; first and second inflow passages connected to an inlet of the receiver; and first and second outflow passages connected to an outlet of the pump; In a phase change refrigerant circulation unit in which a first inflow channel and a first outflow channel are connected to a primary heat exchanger, and the second inflow channel and the second outflow channel are connected to a secondary heat exchanger,
A first inflow opening / closing valve disposed in the first inflow channel;
A second inflow on-off valve disposed in the second inflow channel;
A second outflow on-off valve disposed in the second outflow channel;
Disposed in the first outflow channel,
When open, it allows flow in both directions,
In a closed state, a first outflow on-off valve that does not allow leakage from the pump to the primary heat exchanger and allows leakage from the primary heat exchanger to the pump;
Disposed in the first outflow channel,
Allowing flow from the pump to the primary heat exchanger;
A phase change refrigerant circulation unit comprising: a third check valve for preventing flow from the primary heat exchanger to the pump. The phase change refrigerant circulation unit according to claim 3,
The phase change refrigerant circulation unit, wherein the third check valve is disposed between the first outflow on-off valve and the primary heat exchanger. A phase change refrigerant is circulated in an air conditioning system having a primary heat exchanger and a secondary heat exchanger, and a liquid receiver that stores the liquid phase change refrigerant, and a liquid phase of the liquid receiver. A pump for delivering a change refrigerant; first and second inflow passages connected to an inlet of the receiver; and first and second outflow passages connected to an outlet of the pump; In a phase change refrigerant circulation unit in which a first inflow channel and a first outflow channel are connected to a primary heat exchanger, and the second inflow channel and the second outflow channel are connected to a secondary heat exchanger,
A first inflow opening / closing valve disposed in the first inflow channel;
A second inflow on-off valve disposed in the second inflow channel;
A first outflow on-off valve disposed in the first outflow passage;
A second outflow on-off valve disposed in the second outflow channel;
A circulation path connecting the inlet of the receiver and the outlet of the pump;
A circuit opening and closing valve disposed in the circuit,
A phase change refrigerant circulation unit comprising an air heat exchanger provided in the circulation path and performing heat exchange between the phase change refrigerant and unheated air. The phase change refrigerant circulation unit according to claim 5,
The air heat exchanger is installed in an unheated space,
A liquid level sensor provided in the liquid receiver;
A circulation path control unit that closes the circulation path opening / closing valve at a normal time and opens the circulation path opening / closing valve when a drop in the liquid level in the liquid receiver is detected by the liquid level sensor during heating operation. A phase change refrigerant circulation unit characterized by that. A primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, First and second inflow channels connected to the inlet, and first and second outflow channels connected to the outlet of the pump, wherein the first inflow channel and the first outflow channel are the An air conditioning system connected to a primary heat exchanger, wherein the second inflow channel and the second outflow channel are connected to the secondary heat exchanger;
A first outflow on-off valve disposed in the first outflow passage;
A second outflow on-off valve disposed in the second outflow channel;
Disposed in the first inflow channel,
When open, it allows flow in both directions,
In a closed state, a first inflow opening / closing valve that does not allow leakage from the primary heat exchanger to the liquid receiver and permits leakage from the liquid receiver to the primary heat exchanger;
Disposed in the first inflow channel,
Allowing flow from the primary heat exchanger to the receiver;
A first check valve that blocks flow from the receiver to the primary heat exchanger;
Disposed in the second inflow channel,
When open, it allows flow in both directions,
In a closed state, a second inflow on-off valve that does not allow leakage from the secondary heat exchanger to the liquid receiver and permits leakage from the liquid receiver to the secondary heat exchanger;
Disposed in the second inflow channel,
Allowing flow from the secondary heat exchanger to the receiver;
An air conditioning system comprising: a second check valve that blocks a flow from the liquid receiver to the secondary heat exchanger. A primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, First and second inflow channels connected to the inlet, and first and second outflow channels connected to the outlet of the pump, wherein the first inflow channel and the first outflow channel are the An air conditioning system connected to a primary heat exchanger, wherein the second inflow channel and the second outflow channel are connected to the secondary heat exchanger;
A first inflow opening / closing valve disposed in the first inflow channel;
A second inflow on-off valve disposed in the second inflow channel;
A second outflow on-off valve disposed in the second outflow channel;
Disposed in the first outflow channel,
When open, it allows flow in both directions,
In a closed state, a first outflow on-off valve that does not allow leakage from the pump to the primary heat exchanger and allows leakage from the primary heat exchanger to the pump;
Disposed in the first outflow channel,
Allowing flow from the pump to the primary heat exchanger;
An air conditioning system comprising: a third check valve that blocks flow from the primary heat exchanger to the pump. A primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, First and second inflow channels connected to the inlet, and first and second outflow channels connected to the outlet of the pump, wherein the first inflow channel and the first outflow channel are the An air conditioning system connected to a primary heat exchanger, wherein the second inflow channel and the second outflow channel are connected to the secondary heat exchanger;
A first inflow opening / closing valve disposed in the first inflow channel;
A second inflow on-off valve disposed in the second inflow channel;
A first outflow on-off valve disposed in the first outflow passage;
A second outflow on-off valve disposed in the second outflow channel;
A circulation path connecting the inlet of the receiver and the outlet of the pump;
A circuit opening and closing valve disposed in the circuit,
An air conditioning system comprising an air heat exchanger that is provided in the circulation path and performs heat exchange between the phase change refrigerant and unheated air. A primary heat exchanger, a secondary heat exchanger, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, First and second inflow channels connected to the inlet, and first and second outflow channels connected to the outlet of the pump, wherein the first inflow channel and the first outflow channel are the An air conditioning system connected to a primary heat exchanger, wherein the second inflow channel and the second outflow channel are connected to the secondary heat exchanger;
A first inflow opening / closing valve disposed in the first inflow channel;
A second inflow on-off valve disposed in the second inflow channel;
A first outflow on-off valve disposed in the first outflow passage;
A second outflow on-off valve disposed in the second outflow passage,
An air conditioning system, wherein a volume of a pipe from an outlet of the pump to an inlet of the primary heat exchanger is smaller than a volume of a portion through which the phase change refrigerant is passed in the secondary heat exchanger.

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