JP2008170045A - Air-conditioning system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioning system and its operation method capable of preventing stagnation of a refrigerant, and surely circulating the refrigerant even with a small liquid receiver. <P>SOLUTION: This air-conditioning system comprising a cold/hot water-side heat exchanger 2, an indoor machine 3, the liquid receiver 12, a pump 11, inflow channels 15, 16, outflow channels 17, 18, a refrigerant gas pipe 6 connecting a gas-phase refrigerant opening of the cold/hot water-side heat exchanger 2 and a gas-phase refrigerant opening of the indoor machine 3, outflow opening and closing valves 26, 27 disposed in the outflow channels, and inflow opening and closing valves 21, 24 disposed in the inflow channels, further comprises a heating operation start control portion performing a liquid recovering processing for recovering the liquid-phase phase-change refrigerant from the refrigerant gas pipe 6 and the cold/hot water-side heat exchanger 2 to the liquid receiver 12 by charging the hot water into the cold/hot water-side heat exchanger 2 and evaporating the liquid-phase phase-change refrigerant in a state that the outflow opening and closing valve 26 is closed, the inflow opening and closing valve 24 is opened, and the pump 11 is stopped in starting the heating operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air-conditioning system used for air-conditioning equipment in a building and an operation method thereof. More specifically, the present invention relates to an air conditioning system that uses cold / hot water on the primary side and a phase change refrigerant on the secondary side and circulates the phase change refrigerant using a pump, and an operation method thereof. .

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.
Japanese Patent No. 3680043

  However, the above-described conventional equipment has a problem that refrigerant stagnation occurs after the heating operation is stopped during the heating period. For example, the temperature around the indoor unit becomes low at night, and the gas refrigerant in the flow path and indoor unit liquefies and accumulates. When the heating operation is started in this state, there is a possibility that the refrigerant cannot be circulated because there is not a sufficient amount of refrigerant in the receiver. Further, even during the cooling operation period, when the load is relatively small, the gas refrigerant may liquefy in the refrigerant gas pipe and fall asleep.

  In addition, in a cooling / heating facility such as a building, the connection is generally made so that the total capacity of the indoor unit on the secondary side is slightly larger than the heat exchange capacity on the primary side. Therefore, especially when many indoor units are used at the same time with high output during the cooling operation period, there is a possibility that the heat exchange capacity on the primary side may be exceeded. In this case, there is a problem that the supercooling of the liquid refrigerant is reduced, which causes poor refrigerant circulation.

  Further, in the refrigerant circulation unit in which such refrigerant circulation equipment is unitized, the size of the liquid receiver dominates the overall size, which is an obstacle to miniaturization. Therefore, there has been a demand for a device that can use a smaller liquid receiver without causing poor circulation.

  The present invention has been made in order to solve the problems of the conventional equipment described above. That is, an object of the present invention is to provide an air-conditioning system and a method for operating the same that prevent refrigerant stagnation and can reliably circulate the refrigerant even with a small liquid receiver.

  The air conditioning system of the present invention, which has been made for the purpose of solving this problem, includes a primary heat exchanger, a secondary heat exchanger, a receiver that contains a liquid phase change refrigerant, and a liquid phase of the receiver. A pump for delivering the phase change refrigerant, an outlet passage connecting the outlet of the pump and the liquid phase refrigerant port of the primary heat exchanger, an inlet of the liquid receiver, and a liquid phase refrigerant port of the secondary heat exchanger A connecting inflow channel, a gas channel connecting a gas phase refrigerant port of the primary heat exchanger and a gas phase refrigerant port of the secondary heat exchanger, an outflow on-off valve disposed in the outflow channel, and an inflow channel An air-conditioning system having an inflow on-off valve arranged at the same time, when heating operation is started, with the outflow on-off valve closed, the inflow on-off valve opened and the pump stopped, hot water is charged into the primary heat exchanger A liquid recovery process for recovering the liquid phase change refrigerant from the gas flow path and the secondary heat exchanger to the receiver by vaporizing the phase change refrigerant. And it has a heating operation startup control unit that performs.

  In the air conditioning system of the present invention, the liquid phase change refrigerant accommodated in the liquid receiver is sent out by the pump and flows to the primary heat exchanger via the outflow channel. During the heating operation, a heat source is prepared in the primary heat exchanger, where the phase change refrigerant is vaporized. The phase change refrigerant that has become a gas phase flows through the gas flow path to the secondary heat exchanger, where it is liquefied. Further, the phase change refrigerant that has become a liquid phase is accommodated in the liquid receiver via the inflow channel.

  In such a system, according to the present invention, since the heating operation start control unit is provided, the liquid recovery process is performed when the heating operation is started. That is, warm water is poured into the primary heat exchanger with the outflow on-off valve closed, the inflow on-off valve opened and the pump stopped. As a result, the phase change refrigerant remaining in the primary heat exchanger is vaporized, and the pressure of the refrigerant is highest in the primary heat exchanger. And since a pressure becomes low in order of a gas channel, a secondary heat exchanger, an inflow channel, and a liquid receiver, a refrigerant flows in this order and is collected by a liquid receiver. Furthermore, in the part after the gas flow path, the refrigerant pressure is higher than the saturation pressure corresponding to the temperature, so the refrigerant is in a supercooled state. Therefore, the inflow channel and the liquid receiver are filled with the liquid phase change refrigerant, and the phase change refrigerant is collected in the liquid receiver.

  Further, in the present invention, the heating operation start-up control unit drives the pump for a predetermined time from the liquid receiver to the primary heat exchanger with the outflow on-off valve opened and the inflow on-off valve closed before the liquid recovery process. It is desirable to perform a preliminary liquid feeding process for sending a liquid phase change refrigerant. This ensures that the liquid phase change refrigerant is present in the primary heat exchanger at the start of the liquid recovery process.

  Furthermore, in the present invention, the liquid level sensor for detecting the liquid level of the liquid receiver is provided, and the controller at the start of heating operation finishes the liquid recovery process when the liquid level of the liquid receiver reaches a predetermined value. It is desirable to shift to normal heating operation. In this way, a predetermined amount of phase change refrigerant is recovered in the liquid receiver, so that good refrigerant circulation is possible.

  Furthermore, in the present invention, it is desirable that the heating operation start-up control unit stop the operation when the liquid level of the liquid receiver does not reach a predetermined value within a predetermined time after the liquid recovery process is started. In this way, it can be easily seen that a predetermined amount of phase change refrigerant does not exist in the system for some reason.

  Further, in the present invention, it is desirable that the secondary heat exchanger is provided with a blower fan, and that the heating operation start time control unit prohibits driving of the blower fan until the liquid recovery process is completed at the start of the heating operation. In this way, the phase change refrigerant is prevented from being liquefied in the secondary heat exchanger, and the phase change refrigerant can be reliably recovered.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, a liquid receiver that houses a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, An outflow passage that connects the outlet of the liquid and the liquid phase refrigerant port of the primary heat exchanger, an inflow passage that connects the inlet of the liquid receiver and the liquid phase refrigerant port of the secondary heat exchanger, and the primary heat exchanger Air conditioner having a gas flow path connecting the gas-phase refrigerant port of the secondary heat exchanger and the gas-phase refrigerant port of the secondary heat exchanger, an outflow on-off valve arranged in the outflow passage, and an inflow on-off valve arranged in the inflow passage The system operation method, when heating operation is started, with the outflow on-off valve closed, the inflow on-off valve opened and the pump stopped, hot water is poured into the primary heat exchanger to vaporize the liquid phase change refrigerant Therefore, the operation method of the air conditioning system that performs the liquid recovery process for recovering the liquid phase change refrigerant from the gas flow path and the secondary heat exchanger to the receiver is also included. Department.

  Further, in the operation method of the air conditioning system of the present invention, prior to the liquid recovery process, the pump is driven for a predetermined time with the outflow on-off valve opened and the inflow on-off valve closed, and the liquid phase is transferred from the liquid receiver to the primary heat exchanger. It is desirable to perform preliminary liquid feeding processing for sending the phase change refrigerant.

  The air-conditioning system of the present invention also delivers a primary heat exchanger, a plurality of secondary heat exchangers, a receiver that contains a liquid phase change refrigerant, and a liquid phase change refrigerant of the receiver. , An inflow flow connecting the outlet of the pump and the liquid refrigerant port of the primary heat exchanger, and the inlet of the receiver and the liquid refrigerant ports of the secondary heat exchangers And an air conditioning system having a gas flow path connecting the gas-phase refrigerant ports of the primary heat exchanger and the gas-phase refrigerant ports of the plurality of secondary heat exchangers. It has an overload control unit that performs forced reduction processing to reduce the operation load of a plurality of secondary heat exchangers when the total operation load of the heat exchanger exceeds the capacity of the primary heat exchanger. .

  According to the present invention, the overload control unit is provided, so that the forced reduction process is performed when the total operation load of the plurality of secondary heat exchangers exceeds the capacity of the primary heat exchanger during the heating operation. Is called. That is, by reducing the operating load of the secondary heat exchanger, the total operating load of the secondary heat exchanger is adjusted so as not to exceed the capacity of the primary heat exchanger. Therefore, the liquid phase change refrigerant is brought into a supercooled state, and refrigerant circulation failure is prevented.

  Furthermore, in the present invention, a water temperature sensor that detects the temperature of the cold water outlet of the primary heat exchanger, a pressure sensor that detects the pressure of the gas flow path, a gas temperature sensor that detects the temperature of the gas flow path, A target temperature setting unit for setting a target temperature of the gas flow path based on the pressure of the passage and the temperature of the cold water outlet of the primary heat exchanger. When the gas flow path temperature is lower than the target temperature, the liquid phase phase change refrigerant delivery amount from the liquid receiver is increased, and when the gas flow path temperature is higher than the target temperature, It is desirable to perform a refrigerant flow rate adjustment process that reduces the amount of liquid phase change refrigerant delivered. In this way, the saturation conversion temperature of the phase change refrigerant is adjusted, and the liquid phase change refrigerant can be sufficiently subcooled.

  The present invention also includes a primary heat exchanger, a plurality of secondary heat exchangers, a receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the receiver, , An outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the primary heat exchanger, an inflow passage connecting the inlet of the liquid receiver and the liquid phase refrigerant ports of the plurality of secondary heat exchangers, An operation method of an air conditioning system having a gas flow path connecting a gas phase refrigerant port of a primary heat exchanger and gas phase refrigerant ports of a plurality of secondary heat exchangers, This also extends to an operation method of an air conditioning system that performs forced reduction processing to reduce the operation load of a plurality of secondary heat exchangers when the total operation load of the heat exchanger exceeds the capacity of the primary heat exchanger.

  Further, in the operation method of the air conditioning system according to the present invention, the target temperature of the gas flow path is set based on the pressure of the gas flow path and the water temperature of the cold / hot water outlet of the primary heat exchanger, and after the forced reduction process, When the flow path temperature is lower than the target temperature, the liquid-phase phase change refrigerant delivery amount from the receiver is increased, and when the gas flow path temperature is higher than the target temperature, the liquid phase from the receiver is increased. It is desirable to perform refrigerant flow rate adjustment processing that reduces the amount of phase change refrigerant delivered.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger, a liquid receiver that accommodates a liquid phase change refrigerant, , A pump for sending the liquid phase phase change refrigerant of the receiver, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchanger An air-conditioning system having an inflow channel connecting a liquid-phase refrigerant port of the gas and a gas channel connecting a gas-phase refrigerant port of a primary heat exchanger and a gas-phase refrigerant port of a secondary heat exchanger, A gas temperature sensor for detecting the temperature of the flow channel, a gas pressure sensor for detecting the pressure of the gas flow channel, a saturation converted temperature acquisition unit for acquiring the saturated converted temperature based on the pressure of the gas flow channel, and during cooling operation When the temperature of the gas flow path becomes lower than the saturation conversion temperature, the gas flow is achieved by closing the on-off valve for a predetermined time and then opening it. A phase change refrigerant in the inner liquid phase are those having a retentate recovery control unit which performs vaporization recovery process for recovering vaporized.

  According to the present invention, since the retained liquid recovery control unit is provided, the liquid phase phase change refrigerant in the gas channel is vaporized when the temperature of the gas channel becomes lower than the saturation conversion temperature during the cooling operation. The vaporization recovery process is performed. That is, when the on-off valve is closed for a predetermined time and then opened, the liquid phase change refrigerant in the secondary heat exchanger is surely vaporized and recovered. Accordingly, the liquid phase change refrigerant in the gas flow path is also vaporized and recovered.

  Furthermore, in the present invention, a plurality of sets of secondary heat exchangers and on-off valves for the liquid-phase refrigerant ports are provided, and the staying liquid recovery control unit sequentially evaporates and collects the plurality of sets of secondary heat exchangers and on-off valves. It is desirable to perform processing. By performing in order, the phase change refrigerant in the gas flow path is recovered little by little without greatly changing the state of the entire system.

  Furthermore, in the present invention, it is desirable that the staying liquid recovery control unit performs the vaporization recovery process in order from the set of secondary heat exchangers with a large operating load. Since the secondary heat exchanger with a larger operating load is more likely to have a liquid phase change refrigerant, it can be processed efficiently by performing the vaporization recovery process in order.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger, a liquid receiver that accommodates a liquid phase change refrigerant, , A pump for sending the liquid phase phase change refrigerant of the receiver, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchanger The air-conditioning system has an inflow channel connecting the liquid-phase refrigerant port of the gas generator and a gas channel connecting the gas-phase refrigerant port of the primary heat exchanger and the gas-phase refrigerant port of the secondary heat exchanger. When the temperature of the gas flow path becomes lower than the saturation conversion temperature during cooling operation, the liquid-phase phase change refrigerant in the gas flow path is vaporized by closing and opening the on-off valve for a predetermined time. It extends to the operation method of the air-conditioning system which performs the vaporization collection processing to collect.

  Further, the air conditioning system operating method of the present invention is directed to an air conditioning system having a plurality of sets of secondary heat exchangers and on / off valves for the liquid-phase refrigerant ports. Therefore, it is desirable to perform a vaporization recovery process.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger, a liquid receiver that accommodates a liquid phase change refrigerant, , A pump for sending the liquid phase phase change refrigerant of the receiver, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchanger An inflow channel connecting the liquid phase refrigerant port of the gas, a gas channel connecting the gas phase refrigerant port of the primary heat exchanger and the gas phase refrigerant port of the secondary heat exchanger, and an outflow channel disposed in the outflow channel An air-conditioning system having an on-off valve, and after cooling operation is stopped, the pump is driven for a predetermined time with the outflow on-off valve opened to send a liquid phase change refrigerant from the receiver to the secondary heat exchanger, Thereafter, a liquid refrigerant transfer process is performed to close the outflow on-off valve so that the secondary heat exchanger stores the liquid phase change refrigerant during the cooling period. Parts and has a.

  According to the present invention, since the suspension storage control unit is provided, the liquid refrigerant transfer process is performed after the cooling operation is stopped, and the liquid phase change refrigerant is stored in the secondary heat exchanger during the suspension during the cooling period. Therefore, even if the receiver has a small capacity, the liquid phase change refrigerant is reliably stored.

  Further, in the present invention, it is preferable that the secondary storage control unit has a plurality of secondary heat exchangers and the liquid refrigerant transfer processing is performed when the operation of all the secondary heat exchangers is stopped. This will have no effect on normal operating conditions.

  Furthermore, in the present invention, it is desirable that the resting storage control unit stop the cold water charging to the primary heat exchanger after the liquid refrigerant transfer process is completed.

  The present invention also includes a primary heat exchanger, a secondary heat exchanger, an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger, a liquid receiver that accommodates a liquid phase change refrigerant, , A pump for sending the liquid phase phase change refrigerant of the receiver, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchanger An inflow channel connecting the liquid phase refrigerant port of the gas, a gas channel connecting the gas phase refrigerant port of the primary heat exchanger and the gas phase refrigerant port of the secondary heat exchanger, and an outflow channel disposed in the outflow channel A method of operating an air conditioning system having an on-off valve, wherein after a cooling operation is stopped, the pump is driven for a predetermined time with the outflow on-off valve opened and a liquid phase change refrigerant is transferred from the receiver to the secondary heat exchanger. And then the liquid refrigerant transfer process is performed to close the outflow on-off valve, thereby allowing the secondary heat exchanger to store the liquid phase change refrigerant during the cooling period. Also extends to system method of operation.

  According to the air-conditioning system and the operation method thereof of the present invention, it is possible to prevent refrigerant stagnation and to reliably circulate the refrigerant even with a small liquid receiver.

  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 an air conditioning system having a refrigerant circulation unit that uses cold / hot water on the primary side and phase change refrigerant on the secondary side.

  The air conditioning system of this embodiment is a system that uses cold / hot water on the primary side and phase change refrigerant (hereinafter simply referred to as refrigerant) on the secondary side. In such an air conditioning system, as shown in FIG. 1, it has the refrigerant | coolant circulation unit 1, and the cold / hot water side heat exchanger 2 and the indoor unit 3 are connected to this. 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 cold / hot water side heat exchanger 2 is provided with a cold / hot water pipe 4, and the cold / hot water pipe 4 is opened and closed by an electric valve 5. And at the time of air_conditioning | cooling, cold water is poured into the cold / hot water piping 4, and in the cold / hot water side heat exchanger 2, a refrigerant | coolant changes a phase from a gas to a liquid. In addition, hot water flows through the cold / hot water pipe 4 during heating, and the refrigerant changes phase from liquid to gas in the cold / hot water side heat exchanger 2.

  Each indoor unit 3 is connected with 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. This refrigerant gas pipe 6 corresponds to a gas flow path. Each refrigerant liquid pipe 7 is provided with an opening / closing valve 8 and can be switched between open and closed for each indoor unit 3. During the cooling operation, the liquid-phase refrigerant flowing from the refrigerant liquid pipe 7 takes the heat of 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 the heating operation, the gas-phase refrigerant flowing from the refrigerant gas pipe 6 releases heat into the indoor air in the indoor unit 3, changes to the liquid phase, and flows out to the refrigerant liquid pipe 7. In addition, all the indoor units 3 have a ventilation fan.

  Furthermore, in this embodiment, a controller 9 that controls the refrigerant circulation unit 1 is provided. This controller 9 controls the motor-operated valve 5 and the on-off valves 8 in addition to the refrigerant circulation unit 1. Thereby, circulation of the heat medium in the cold / hot water side heat exchanger 2 and each indoor unit 3 is controlled. The controller 9 can always grasp the operation load of each indoor unit 3. An operation signal from the user in the indoor unit 3 is also transmitted to the controller 9. Furthermore, the control from the controller 9 can also control the blower fan and the on-off valve 8 of each indoor unit 3 independently of the user's operation.

  The refrigerant circulation 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. In the refrigerant circulation unit 1, flow paths 15, 16, 17, and 18 are formed around the pump 11 and the liquid receiver 12.

  The flow path 15 connects the connection port 13 and 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 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 pump 11, and a check valve 25 and an opening / closing valve 26 are disposed in the flow path 17 in this order from the connection port 13 side. The flow path 18 connects the pump 11 and the connection port 14, and an open / close valve 27 is disposed in the flow path 18.

  In addition, each flow path 15-18 is merged in the location shown by the black circle in FIG. 1, and is not merged in the other crossing location. The pump 11 pushes liquid phase refrigerant from the liquid receiver 12 to the flow paths 17 and 18 as indicated by arrows in the figure. Accordingly, the channels 15 and 16 correspond to inflow channels, and the channels 17 and 18 correspond to outflow channels. On-off valves 21 and 24 correspond to inflow on-off valves, and on-off valves 26 and 27 correspond to outflow on-off valves.

  The liquid receiver 12 is provided with a liquid level sensor 31 for detecting the liquid level of the stored refrigerant. Further, the refrigerant gas pipe 6 is provided with a gas temperature sensor 32 and a gas pressure sensor 33 in order to measure the temperature and pressure of the internal refrigerant gas. These are arranged near the cold / hot water side heat exchanger 2 in the refrigerant gas pipe 6. A water temperature sensor 34 is provided on the outlet side of the cold / hot water pipe 4 of the cold / hot water side heat exchanger 2.

  Next, a control method of the refrigerant circulation unit 1 in such an air conditioning system will be described. During normal heating operation, the on-off valves 21 and 27 are closed and the on-off valves 24 and 26 are opened. Accordingly, the channels 16 and 17 are opened, and the channels 15 and 18 are closed. The liquid-phase refrigerant sent out from the pump 11 is vaporized by the cold / hot water side heat exchanger 2 through the flow path 17. Furthermore, the refrigerant is introduced into the indoor unit 3 through the refrigerant gas pipe 6. Furthermore, heat is released from the indoor unit 3 to be liquefied and returned to the liquid receiver 12 through the flow path 16.

  In the cooling operation, the on-off valves 24 and 26 are closed and the on-off valves 21 and 27 are opened. Accordingly, the flow paths 15 and 18 are opened, and the flow paths 16 and 17 are closed. The liquid-phase refrigerant sent out from the pump 11 is introduced into the indoor unit 3 through the flow path 18. Heat is taken away by the indoor unit 3 and vaporized, and liquefied by the cold / hot water side heat exchanger 2 through the refrigerant gas pipe 6. Further, the liquid is returned to the liquid receiver 12 through the flow path 15.

In the air conditioning system of this embodiment, in addition to these controls during normal operation, one of the following processes is executed depending on the situation. That is,
[1] Liquid recovery process performed at system startup during heating operation
[2] Operation load monitoring processing (including forced reduction processing and refrigerant flow rate adjustment processing) that is performed particularly during the extremely cold season during heating operation,
[3] Vaporization recovery processing performed at low load during cooling operation,
[4] Liquid refrigerant transfer processing performed during cooling operation in a system having a small liquid receiver,
These are the four types of control methods.

  First, the liquid recovery process performed when the system is started during the heating operation period [1] will be described with reference to the flowchart of FIG. During the heating operation period in winter, the temperature around the pipes and indoor units may be low during operation stoppages such as at night, and liquefied refrigerant may accumulate in the indoor units. Therefore, in this embodiment, at the time of starting the system, first, a liquid recovery process for recovering the refrigerant in the liquid receiver 12 is performed. This processing is started from a state in which all the devices of the system are stopped before the heating operation of each room is started, for example, in the morning of winter. That is, at the start of the execution of this process, all of the motor operated valves 5 and the on-off valves 8, 21, 24, 26, 27 are closed, and the operation of all the indoor units 3 and the pumps 11 are also stopped. Then, when the operation switch of any one of the indoor units in the system is pressed, this processing is started first.

  While the system is stopped, the controller 9 stands by until the operation switch of any indoor unit 3 is turned on (S101). If even one of the indoor units 3 is turned on (S101: Yes), the process proceeds to the next. Then, the fans of all the indoor units 3 that are turned on are forcibly stopped by the controller 9 (S102). That is, the on-off valve 8 of the indoor unit 3 is opened and the fan is not driven. As a result, the refrigerant is circulated through the indoor unit 3, but the indoor unit 3 is not blown. Therefore, the pressure of the refrigerant system does not drop because the gaseous refrigerant is liquefied in the indoor unit 3. The forced stop state of the fan continues even if the user performs any operation on each indoor unit 3 until it is canceled during this process.

  Subsequently, the on-off valve 26 is opened (S103), and the pump 11 is operated for about 30 seconds (S104). Stop for about 30 seconds. Thereby, a small amount of the liquid-phase refrigerant stored in the liquid receiver 12 is sent from the pump 11 to the cold / hot water side heat exchanger 2 via the on-off valve 26. Next, the on-off valve 26 is closed and the on-off valve 24 is opened (S105). Furthermore, the motor-operated valve 5 is controlled, and hot water of, for example, 45 ° C. or more is poured into the cold / hot water pipe 4 (S106).

Thereby, the refrigerant | coolant sent in the cold / hot water side heat exchanger 2 by S104 is vaporized. Assuming that the temperature of the hot water charged in S106 is T1, the refrigerant becomes a saturated gas slightly lower in temperature than the temperature T1 of the hot water. Let this saturated gas temperature be T2. At this time, since the surroundings of the indoor unit 3 (here, temperature T3) and the receiver 12 (temperature T4) are not warmed, the saturated gas temperature T2 is compared with these temperatures T3, T4. High enough. That is, T1, T2, T3, and T4 have the following relationship.
T1 >> T2 >> T3≈T4

Further, since the pressure in the system is based on the saturation pressure at the temperature T2, the portion up to the receiver 12 through the indoor unit 3 and the refrigerant liquid pipe 7 that are sufficiently cooler than this is in a supercooled state. Therefore, all refrigerants in this range are in a liquid phase state. The relationship between the pressures at each part is as follows.
Internal pressure of the cold / hot water side heat exchanger 2> Internal pressure of the indoor unit 3> Internal pressure of the liquid receiver 12 Accordingly, a liquid refrigerant flow of the cold / hot water side heat exchanger 2 → the indoor unit 3 → the liquid receiver 12 can be made, Liquid phase refrigerant is recovered in the liquid receiver 12.

  Accordingly, the height of the liquid level in the liquid receiver 12 is detected by the liquid level sensor 31, and when a sufficient amount of refrigerant is recovered in the liquid receiver 12 (S107: Yes), the refrigerant recovery operation is terminated and the normal operation is performed. Transition to operation. That is, first, the on-off valve 26 is opened (S108), and the pump 11 is operated (S109). Furthermore, the forced stop state of the fan of the indoor unit 3 is canceled (S110). Thereby, the fan of the indoor unit 3 whose operation switch is first turned on starts to rotate. In addition, if there is one in which the operation switch is turned on during this processing, the fan starts to rotate for the first time at the same time for the indoor unit 3 as well. Thereafter, each indoor unit 3 follows the user's operation. This is the end of this process.

  Here, if the liquid level sensor 31 cannot detect the liquid level even after 10 minutes have passed since the start of charging hot water into the cold / hot water pipe 4 of the cold / hot water side heat exchanger 2 (S111: Yes), It is determined that the above refrigerant recovery is impossible. It is thought that the total amount of refrigerant is decreasing due to leakage of refrigerant from somewhere in the system. Therefore, in this case, the administrator is notified of the abnormality (S112), and all system operations are stopped (S113). This concludes the description of this process.

  Next, the operation load monitoring process during the heating operation of [2] will be described with reference to the flowchart of FIG. This process is always performed during the heating operation during the winter heating operation. In general, in a building air conditioner such as a residential building, it is often installed such that the total capacity of the indoor unit 3 is about 150% of the capacity of the cold / hot water side heat exchanger 2 corresponding to the heat source unit. Actually, since all the indoor units 3 are rarely operated at the maximum load, there is almost no problem even if they are installed in this way.

  The state change of the refrigerant in the general heating operation is governed by the cold / hot water side heat exchanger 2 as an evaporator, and is roughly circulated as shown by the cycle A in the Mollier diagram of FIG. That is, at the left end of the cycle A diagram, the pressure is increased due to compression by the pump 11. Next, by receiving the heat of the hot water in the cold / hot water side heat exchanger 2 and evaporating, the upper side in the figure moves from the left to the right, and the specific enthalpy increases. Next, the right end in the figure shows the pressure loss in the middle of flowing through the refrigerant gas pipe 6. Then, the indoor unit 3 releases heat to the indoor air to condense, and the specific enthalpy decreases. At this time, the lower side of the cycle A diagram is moved from right to left. In the range of this figure, the upper part in the figure is the high temperature region and the lower part in the figure is the low temperature region.

  However, if the indoor unit 3 is operated exceeding the capacity of the heat source unit, the refrigerant temperature and pressure are controlled by the indoor unit 3 functioning as a condenser. That is, the cycle A is changed to the cycle B as shown in the Mollier diagram of FIG. Therefore, the pressure and temperature of the refrigerant decrease as a whole cycle, and the blowing temperature of the indoor unit 3 during operation decreases. Furthermore, since the degree of supercooling is reduced from about 4 ° C. to about 1 ° C., an unstable operating state is likely to cause refrigerant circulation failure. If a refrigerant circulation failure occurs, heating operation cannot be performed. In view of this, the present process is to appropriately monitor the operating load of the indoor unit 3 and adjust it to an appropriate operating state so that the operating state under the control of the indoor unit 3 does not occur.

  When the heating operation is started, the processing is started. Then, as shown in FIG. 3, the controller 9 constantly monitors changes in the operation state such as operation switches being operated in each indoor unit 3 or heating output being switched (S201). If there is no change (S201: No), monitoring is continued as it is. When the operation state is changed (S201: Yes), the operation loads of the indoor units 3 in operation are totaled, and the total is compared with the capacity of the cold / hot water side heat exchanger 2 (S202). If the total operation load of the indoor unit 3 in operation does not exceed the capacity of the cold / hot water side heat exchanger 2 (S202: No), the operation is continued and there is no problem. Therefore, the process returns to S201 and is continuously monitored.

  On the other hand, when the total operation load of the indoor unit 3 during operation exceeds the capacity of the cold / hot water side heat exchanger 2 (S202: Yes), the operation load of the indoor unit 3 during operation is determined by the controller 9. Forcible lowering processing for forced control is performed (S203). That is, the operation state of each indoor unit 3 is changed so that the total operation load of the indoor units 3 during operation does not exceed the capacity of the cold / hot water side heat exchanger 2. For example, the fan air volume of the indoor unit 3 during operation is forcibly lowered by one rank. In general, the fan air volume of the indoor unit 3 can be changed to about 3 to 5 stages. If the degree of surpassing is large, it may be changed more drastically.

  When the operation state of each indoor unit 3 is controlled in S203, a refrigerant flow rate adjusting process for adjusting the refrigerant flow rate is further performed. For this purpose, first, the refrigerant pressure at the outlet of the cold / hot water side heat exchanger 2 is obtained from the detection result of the gas pressure sensor 33 (S204). Next, the saturation conversion temperature Tg is acquired based on the pressure obtained in S204 (S205). The relationship between the gas pressure and its saturation temperature is determined for each type of refrigerant and may be stored in the controller 9 as a table, for example. An example of the relationship between the refrigerant gas pressure and the refrigerant saturation temperature is shown in FIG.

  Further, the hot water outlet temperature Tw of the cold / hot water side heat exchanger 2 is obtained from the detection result of the water temperature sensor 34. These temperatures are compared, and it is determined whether or not the saturation conversion temperature Tg at the gas pressure is about 2 ° C. lower than the hot water outlet temperature Tw (S206). This temperature of 2 ° C. is the minimum temperature, and is an optimum temperature under this situation that tends to be overloaded. If Tg = Tw−2 (° C.), the optimum refrigerant circulation amount is obtained so that the optimum gas pressure can be obtained. Therefore, it is only necessary to return to S201 and continue monitoring.

  On the other hand, if the saturation conversion temperature Tg at the gas pressure is not the optimum temperature as a result of S206, the refrigerant circulation amount is adjusted so as to be an appropriate refrigerant gas pressure. For example, if the saturation conversion temperature Tg is too low compared to the optimum temperature and Tg <Tw−2 (° C.) in S206, it means that the gas pressure is too low. Accordingly, in this case, the saturation conversion temperature Tg is increased by increasing the refrigerant flow rate and increasing the refrigerant pressure (S207).

  Alternatively, if the saturation conversion temperature Tg is too high compared to the optimum temperature and Tg> Tw−2 (° C.) in S206, it means that the gas pressure is too high. Therefore, the saturation conversion temperature Tg is lowered by decreasing the refrigerant flow rate to reduce the refrigerant gas pressure (S208).

  In addition, the process of S207 and S208 should just change the driving | running rotation speed of the pump 11 with an inverter specifically ,. Alternatively, an adjustment valve capable of adjusting the opening degree may be provided between the pump 11 and the cold / hot water side heat exchanger 2 instead of the on-off valve 26 or in addition to the on-off valve 26. If it does in this way, the flow volume of a refrigerant | coolant can be adjusted with the opening degree of this adjustment valve. After adjusting the flow rate of the refrigerant, the process returns to the monitoring state of S201 again.

  In this way, it is always monitored whether the total operation load of the indoor unit 3 exceeds the capacity of the cold / hot water heat exchanger 2, and if it exceeds, the fan air volume of the indoor unit 3 is controlled. , Forcibly reduce the operation load of the indoor unit 3. Therefore, it is possible to maintain the state in which the evaporator side dominates the refrigerant cycle (the state of cycle A in FIG. 4). Further, by controlling the supercooling to about 2 ° C., it is possible to obtain as high a heating capacity as possible while avoiding poor refrigerant circulation. As a result, it is a monitoring process that prevents the blowing temperature from decreasing and avoids poor circulation only by slightly suppressing the air flow.

  Next, the vaporization recovery process during the cooling operation of [3] will be described with reference to the flowchart of FIG. There are days when the temperature is relatively low even during the cooling period. On such days, the thermal load is small, and the entire system becomes very cold. For this reason, the refrigerant sometimes liquefies and accumulates in the pipe in the range where the gas-phase refrigerant such as the refrigerant gas pipe exists. In this case, the flow path of the refrigerant gas pipe becomes narrow, and the pressure loss increases, which causes a decrease in dehumidification performance. In this embodiment, the state of the refrigerant gas pipe during the cooling operation is monitored to prevent liquid refrigerant from accumulating. This process is automatically started at appropriate time intervals during the cooling operation.

  When this process is started, the controller 9 first acquires the temperature and pressure of the refrigerant gas in the refrigerant gas pipe 6. For this purpose, the temperature is measured by the gas temperature sensor 32 (S301). This temperature is defined as temperature T. Further, the pressure is measured by the gas pressure sensor 33 (S302). Subsequently, based on the pressure obtained in S302, the saturation conversion temperature Ts is obtained from the same table as [2] (S303).

  Next, the temperature T resulting from S301 is compared with the temperature Ts resulting from S303 (S304). If the gas temperature T is higher than the saturation conversion temperature Ts (S304: Yes), the refrigerant gas pipe 6 is superheated and there is no possibility that liquid-phase refrigerant is accumulated. Therefore, in this case, it is a normal state, and it is only necessary to continue the cooling operation in this state.

  However, when the gas temperature T is equal to or lower than the saturation conversion temperature Ts (S304: No), there is no degree of superheat. Therefore, there is a possibility that the liquid phase refrigerant is accumulated in the refrigerant gas pipe 6. Here, the refrigerant gas pipe 6 is generally thicker than the refrigerant liquid pipe 7 and is often covered with a heat insulating material. In such a case, once the liquid-phase refrigerant has accumulated, it cannot be evaporated and collected by itself while continuing the cooling operation in that state.

  Therefore, in this embodiment, when T−Ts ≦ 0 (S304: No), the liquid refrigerant recovery process is performed. First, of the indoor units 3 that are in operation, the indoor unit that is operating with the highest load is selected. That is, one indoor unit 3 having the lowest set temperature and the large fan air flow is selected. Then, the on-off valve 8 of the indoor unit 3 is temporarily closed, and is opened again after about 5 minutes (S305). As a result, the refrigerant remaining in the liquid phase in the indoor unit 3 can be vaporized and recovered. At this time, the fan of the indoor unit 3 is not stopped. If it is about 5 minutes, the room temperature will not increase so much, so there is no problem in terms of experience.

  By doing so, the liquid-phase refrigerant remaining in the indoor unit 3 is vaporized and recovered. At that time, it becomes a relatively high-temperature gas-phase refrigerant, passes through the refrigerant gas pipe 6, and touches the liquid-phase refrigerant accumulated in the refrigerant gas pipe 6 on the way. Therefore, the temperature of the liquid phase refrigerant in the refrigerant gas pipe 6 also rises and is vaporized and recovered together.

  Subsequently, the on-off valve 8 of the indoor unit 3 performing the operation with the second largest load is once closed and opened again after 5 minutes (S306). Thus, the on-off valve 8 of the indoor unit 3 is closed one by one in order from the largest load, and the liquid refrigerant inside is evaporated. Finally, the on-off valve 8 of the indoor unit 3 with the smallest load is closed for 5 minutes and then opened again (S307). In addition, although it is desirable to carry out one unit at a time in this way, in a system with a large number of connected indoor units 3 or an indoor unit 3 with a small capacity, two or three units may be simultaneously performed.

  By doing in this way, the liquid-phase refrigerant | coolant which remained in each indoor unit 3 is vaporized in order, and is collect | recovered in order. In the course of the recovery, the liquid phase refrigerant in the refrigerant gas pipe 6 is also vaporized and recovered together. When valve opening / closing of all the indoor units 3 is completed, the process returns to S301 again.

  Then, the gas pipe temperature T and the gas pipe pressure are measured, and the saturation conversion temperature Ts and the gas pipe temperature T are compared. If T-Ts> 0 is satisfied (S304: Yes), this process is terminated. If not, the process from S305 to S307 is repeated once again. In this air conditioning system, this vaporization recovery process is executed as appropriate during the cooling operation.

  Next, the liquid refrigerant transfer process performed during the cooling operation period in the system having the small liquid receiver of [4] will be described with reference to the flowchart of FIG. In general, in an air conditioning system using refrigerant, the total amount of refrigerant required for cooling operation and heating operation differs. During cooling operation, it is sufficient to circulate a smaller amount of refrigerant than during heating operation. This is because the operating temperature level is different and the amount of refrigerant required to maintain the pressure corresponding to that temperature is different.

  In the case of using a predetermined amount of refrigerant sealed in the system as in the system of this embodiment, a larger amount of refrigerant required for heating operation is prepared. For this reason, the refrigerant becomes surplus during the cooling operation period, and the surplus is basically stored and stored in the liquid receiver 12. In particular, since many liquid-phase refrigerants are collected during shutdown, the total amount is considerable. In order to collect all the excess refrigerant in the liquid receiver 12, a large liquid receiver 12 is required, and the size of the entire refrigerant circulation unit 1 is also increased. In this embodiment, the space for storing the excess liquid-phase refrigerant during the cooling operation period, particularly during the operation stop, is secured in a place other than the liquid receiver 12 in the system, thereby reducing the size of the liquid receiver 12. Things can be adopted.

  This process is mainly executed after the cooling operation is completed during the cooling operation period. That is, as shown in FIG. 7, first, the cooling operation of the day is started, and the normal cooling operation is performed (S401). The normal operation is continued until the switches of all the indoor units 3 are turned off at the end of work (S402: No).

  When the switches of all the indoor units 3 are turned off (S402: Yes), the open / close valves 8 of the refrigerant liquid pipes 7 of all the indoor units 3 are opened without changing the state of each open / close valve of the refrigerant circulation unit 1 (S403). . Then, the pump 11 is rated for about 1 minute (S404). As a result, the refrigerant is sent to the refrigerant liquid pipe 7, and the liquid-phase refrigerant is sent into each indoor unit 3 through the on-off valve 8.

  In this state, the on-off valve 8 of the refrigerant liquid pipe 7 of all the indoor units 3 is closed (S405). As a result, a liquid phase refrigerant is accumulated in each indoor unit 3. Further, all the on-off valves of the refrigerant circulation unit 1 are closed (S406), and the refrigerant circulation is stopped. Subsequently, the supply of cold water to the cold / hot water pipe 4 of the cold / hot water side heat exchanger 2 is stopped (S407). By stopping the cold water last, it is possible to prevent the refrigerant from being vaporized and cavitation during the process. This is the end of the process, and it is held in this state until it is started again the next morning.

  When starting in the morning of the next day, operation may be started as usual. For example, even if the heat exchanger of the indoor unit 3 is submerged in a liquid phase refrigerant of about 300 mm, this amount of head is less than 1 ° C. in terms of temperature. Therefore, it does not have a great influence on the room temperature. In addition, here, this process is executed after the cooling operation is completed. However, if the refrigerant becomes excessive during the cooling operation, the liquid refrigerant is stored in the indoor unit 3 to some extent as in this process. Also good. Even if the heat exchanger of the indoor unit 3 is submerged in the liquid refrigerant to some extent, there is almost no problem. In particular, if there is an indoor unit 3 that is stopped, it is preferable to select it and open the on-off valve 8.

  By doing so, a liquid receiver 12 having a size about 1/3 of the conventional one can be selected. Therefore, according to the present embodiment, since the refrigerant circulation unit 1 using the small liquid receiver 12 can be obtained, the overall size of the refrigerant circulation unit 1 can be reduced.

As described in detail above, according to the control method of the refrigerant circulation unit 1 of the present embodiment, the following four processes are performed.
[1] Liquid recovery processing is performed when the system is started during the heating operation period. [2] Operation load monitoring processing (including forced reduction processing and refrigerant flow rate adjustment processing) is performed particularly during severe cold periods during heating operation. [3] Cooling [4] Especially in a system with a small liquid receiver, the liquid refrigerant transfer process is performed during the cooling operation period. This is a heat exchanger pump system that can reliably circulate the refrigerant.

  In the present system, during the heating operation period, [1] is executed at the time of startup, and [2] is executed during the operation. Further, during the cooling operation period, [3] is executed during operation, and [4] is executed when operation is stopped. The controller 9 detects the system status and selects and executes an appropriate process.

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, numerical values such as time and temperature are examples and are not limited thereto. In the operational load monitoring process [2], the operational load is compared when the operational state is changed. However, the comparative monitoring may be performed at an appropriate timing at any time regardless of changes in the operational state.

It is a lineblock diagram showing a schematic structure of an air-conditioning system concerning this form. It is a flowchart which shows the liquid collection | recovery process at the time of heating starting. It is a flowchart which shows the load adjustment process in heating operation. It is a Mollier diagram which shows the state change of the refrigerant | coolant during heating operation. It is a graph which shows the relationship between the pressure of a refrigerant | coolant, and saturation temperature. It is a flowchart which shows the monitoring process in air_conditionaing | cooling operation. It is a flowchart which shows the process at the time of the cooling operation completion | finish in the system which has a small liquid receiver.

Explanation of symbols

2 Heating / cooling water side heat exchanger 3 Indoor unit 6 Refrigerant gas pipe 8 Open / close valve 9 Controller 11 Pump 12 Receiver 15, 16 Inflow channel 17, 18 Outflow channel 21, 24 Inflow on / off valve 26, 27 Outflow on / off valve 31 Liquid level sensor 32 Gas temperature sensor 33 Gas pressure sensor 34 Water temperature sensor

Claims (20)

A primary heat exchanger; a secondary heat exchanger; a receiver that contains a liquid phase change refrigerant; a pump that delivers the liquid phase change refrigerant of the receiver; an outlet of the pump; An outflow channel connecting the liquid phase refrigerant port of the primary heat exchanger, an inflow channel connecting the inlet of the receiver and the liquid phase refrigerant port of the secondary heat exchanger, and the primary heat exchange A gas flow path connecting the gas phase refrigerant port of the storage unit and the gas phase refrigerant port of the secondary heat exchanger, an outflow on-off valve disposed in the outflow channel, and an inflow on-off valve disposed in the inflow channel In an air conditioning system having
When heating operation is started, the outflow on-off valve is closed, the inflow on-off valve is opened and the pump is stopped, and hot water is introduced into the primary heat exchanger to vaporize the liquid phase change refrigerant, An air conditioning system comprising: a heating operation start-up control unit that performs a liquid recovery process of recovering a liquid phase change refrigerant from the gas flow path and the secondary heat exchanger to the liquid receiver. The air conditioning system according to claim 1, wherein the heating operation start-up control unit includes:
Prior to the liquid recovery process, with the outflow on-off valve opened and the inflow on-off valve closed, the pump is driven for a predetermined time to supply liquid phase change refrigerant from the receiver to the primary heat exchanger. An air conditioning system characterized by performing preliminary liquid feeding processing. The air conditioning system according to claim 1 or 2,
A liquid level sensor for detecting a liquid level of the liquid receiver;
When the liquid level of the liquid receiver reaches a predetermined value, the heating operation start-up control unit ends the liquid recovery process and shifts to a normal heating operation. The air conditioning system according to claim 3, wherein the heating operation start-up control unit includes:
An air conditioning system characterized in that the operation is stopped when the liquid level of the liquid receiver does not reach a predetermined value within a predetermined time after the liquid recovery process is started. In the air conditioning system according to any one of claims 1 to 4,
The secondary heat exchanger is provided with a blower fan,
The heating operation start time control unit prohibits driving of the blower fan at the time of heating operation start until the liquid recovery process is completed. A primary heat exchanger; a secondary heat exchanger; a receiver that contains a liquid phase change refrigerant; a pump that delivers the liquid phase change refrigerant of the receiver; an outlet of the pump; An outflow channel connecting the liquid phase refrigerant port of the primary heat exchanger, an inflow channel connecting the inlet of the receiver and the liquid phase refrigerant port of the secondary heat exchanger, and the primary heat exchange A gas flow path connecting the gas phase refrigerant port of the storage unit and the gas phase refrigerant port of the secondary heat exchanger, an outflow on-off valve disposed in the outflow channel, and an inflow on-off valve disposed in the inflow channel In the operation method of the air conditioning system having
When heating operation is started, the outflow on-off valve is closed, the inflow on-off valve is opened and the pump is stopped, and hot water is introduced into the primary heat exchanger to vaporize the liquid phase change refrigerant, A method of operating an air conditioning system, wherein a liquid recovery process is performed to recover a liquid phase change refrigerant from the gas flow path and the secondary heat exchanger to the liquid receiver. The operation method of the air conditioning system according to claim 6,
Prior to the liquid recovery process, with the outflow on-off valve opened and the inflow on-off valve closed, the pump is driven for a predetermined time to supply liquid phase change refrigerant from the receiver to the primary heat exchanger. An operation method of an air conditioning system, characterized in that preliminary liquid feeding processing is performed. A primary heat exchanger, a plurality of secondary heat exchangers, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, An outflow channel connecting an outlet and a liquid phase refrigerant port of the primary heat exchanger, an inflow channel connecting an inlet of the receiver and the liquid phase refrigerant ports of the plurality of secondary heat exchangers, In the air conditioning system having a gas flow path connecting the gas phase refrigerant port of the primary heat exchanger and the gas phase refrigerant ports of the plurality of secondary heat exchangers,
When the total operating load of the plurality of secondary heat exchangers exceeds the capacity of the primary heat exchanger during heating operation, a forced reduction process is performed to reduce the operating load of the plurality of secondary heat exchangers. An air conditioning system comprising an overload control unit for performing the operation. The air conditioning system according to claim 8,
A water temperature sensor for detecting a water temperature at a cold / hot water outlet of the primary heat exchanger;
A pressure sensor for detecting the pressure of the gas flow path;
A gas temperature sensor for detecting the temperature of the gas flow path;
A target temperature setting unit for setting a target temperature of the gas flow path based on the pressure of the gas flow path and the water temperature of the cold water outlet of the primary heat exchanger;
The overload control unit, after the forced reduction process,
When the temperature of the gas flow path is lower than the target temperature, increase the delivery amount of the liquid phase change refrigerant from the receiver,
An air conditioning system that performs a refrigerant flow rate adjusting process for reducing a delivery amount of a liquid phase change refrigerant from the liquid receiver when a temperature of the gas flow path is higher than a target temperature. A primary heat exchanger, a plurality of secondary heat exchangers, a liquid receiver that contains a liquid phase change refrigerant, a pump that delivers the liquid phase change refrigerant of the liquid receiver, An outflow channel connecting an outlet and a liquid phase refrigerant port of the primary heat exchanger, an inflow channel connecting an inlet of the receiver and the liquid phase refrigerant ports of the plurality of secondary heat exchangers, In an operating method of an air conditioning system having a gas flow path connecting a gas phase refrigerant port of the primary heat exchanger and gas phase refrigerant ports of the plurality of secondary heat exchangers,
When the total operating load of the plurality of secondary heat exchangers exceeds the capacity of the primary heat exchanger during heating operation, a forced reduction process is performed to reduce the operating load of the plurality of secondary heat exchangers. An operation method of an air conditioning system characterized by being performed. In the operating method of the air conditioning system of Claim 10,
Based on the pressure of the gas flow path and the temperature of the cold heat outlet of the primary heat exchanger, a target temperature of the gas flow path is set,
After the forced reduction process,
When the temperature of the gas flow path is lower than the target temperature, increase the delivery amount of the liquid phase change refrigerant from the receiver,
An operation method of an air conditioning system, wherein a refrigerant flow rate adjustment process is performed to reduce a delivery amount of a liquid phase change refrigerant from the receiver when a temperature of the gas flow path is higher than a target temperature. A primary heat exchanger; a secondary heat exchanger; an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger; a liquid receiver containing a liquid phase change refrigerant; A pump for sending the liquid phase phase change refrigerant of the vessel, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchange An air-conditioning system having an inflow channel connecting a liquid-phase refrigerant port of a storage unit, and a gas channel connecting a gas-phase refrigerant port of the primary heat exchanger and a gas-phase refrigerant port of the secondary heat exchanger,
A gas temperature sensor for detecting the temperature of the gas flow path;
A gas pressure sensor for detecting the pressure of the gas flow path;
A saturation conversion temperature acquisition unit that acquires the saturation conversion temperature based on the pressure of the gas flow path;
When the temperature of the gas flow path becomes lower than the saturation conversion temperature during cooling operation, the phase change refrigerant in the liquid phase in the gas flow path is vaporized by closing and opening the on-off valve for a predetermined time. An air-conditioning system, comprising: a staying liquid recovery control unit that performs a vaporization recovery process of recovering the liquid. The air conditioning system according to claim 12,
It has multiple sets of secondary heat exchangers and on / off valves for the liquid phase refrigerant ports,
The staying liquid recovery control unit sequentially performs the vaporization recovery process on the plurality of sets of secondary heat exchangers and on-off valves. The air conditioning system according to claim 13,
The said staying liquid collection | recovery control part performs the said vaporization collection | recovery process in an order from the group of the secondary heat exchanger with a large operation load. A primary heat exchanger; a secondary heat exchanger; an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger; a liquid receiver containing a liquid phase change refrigerant; A pump for sending the liquid phase phase change refrigerant of the vessel, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchange Of an air-conditioning system having an inflow channel connecting a liquid phase refrigerant port of the storage unit and a gas channel connecting a gas phase refrigerant port of the primary heat exchanger and a gas phase refrigerant port of the secondary heat exchanger In the method,
When the temperature of the gas flow path becomes lower than the saturation conversion temperature during cooling operation, the phase change refrigerant in the liquid phase in the gas flow path is vaporized by closing and opening the on-off valve for a predetermined time. A method of operating an air conditioning system, characterized by performing a vaporization recovery process for recovery. The operation method of the air conditioning system according to claim 15,
Targeting air conditioning systems with multiple sets of secondary heat exchangers and on / off valves for their liquid refrigerant ports,
An operation method of an air conditioning system, wherein the vaporization recovery process is sequentially performed on the plurality of sets of secondary heat exchangers and on-off valves. A primary heat exchanger; a secondary heat exchanger; an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger; a liquid receiver containing a liquid phase change refrigerant; A pump for sending the liquid phase phase change refrigerant of the vessel, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchange An inflow channel connecting the liquid phase refrigerant port of the storage unit, a gas channel connecting the gas phase refrigerant port of the primary heat exchanger and the gas phase refrigerant port of the secondary heat exchanger, and the outflow channel In an air conditioning system having an outflow on-off valve arranged,
After the cooling operation is stopped, the pump is driven for a predetermined time with the outflow on-off valve opened to send a liquid phase change refrigerant from the receiver to the secondary heat exchanger, and then the outflow on-off valve An air conditioning system comprising: a resting storage control unit that stores a liquid phase change refrigerant in the secondary heat exchanger during a resting period during a cooling period by performing a liquid coolant transfer process to be closed. The air conditioning system according to claim 17,
Having a plurality of secondary heat exchangers,
The air-conditioning system, wherein the resting storage control unit performs the liquid refrigerant transfer process when the operation of all the secondary heat exchangers is stopped. The air conditioning system according to claim 17 or claim 18, wherein the resting storage control unit includes:
An air conditioning system characterized in that, after the liquid refrigerant transfer process is finished, the introduction of cold water into the primary heat exchanger is stopped. A primary heat exchanger; a secondary heat exchanger; an on-off valve provided at a liquid phase refrigerant port of the secondary heat exchanger; a liquid receiver containing a liquid phase change refrigerant; A pump for sending the liquid phase phase change refrigerant of the vessel, an outflow passage connecting the outlet of the pump and the liquid phase refrigerant port of the secondary heat exchanger, the inlet of the receiver and the primary heat exchange An inflow channel connecting the liquid phase refrigerant port of the storage unit, a gas channel connecting the gas phase refrigerant port of the primary heat exchanger and the gas phase refrigerant port of the secondary heat exchanger, and the outflow channel In an operating method of an air conditioning system having an outflow on-off valve arranged,
After the cooling operation is stopped, the pump is driven for a predetermined time with the outflow on-off valve opened to send a liquid phase change refrigerant from the receiver to the secondary heat exchanger, and then the outflow on-off valve An operating method of an air conditioning system, wherein a liquid phase change refrigerant is stored in the secondary heat exchanger during a cooling period by performing a closing liquid refrigerant transfer process.

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