JP2016008774A - Chiller system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chiller system in which a plurality of heat pump chillers is connected, capable of determining priorities of chillers waiting for defrosting operation if the defrosting operation is permitted for up to a predetermined number of chillers on first-come-first-served basis.SOLUTION: A chiller system is configured so that a plurality of heat pump chillers regulating a temperature of a circulation liquid for temperature regulation as a heat medium by condensation heat or evaporation heat of refrigerant is connected. One of the chillers is designated as a master chiller. The master chiller permits up to a preset number of chillers to perform defrosting operation on first-come-first-served basis. The chillers waiting for the defrosting operation each transmit a defrosting operation request to the master chiller in a predetermined cycle. If a plurality of chillers waits for the defrosting operation, the master chiller permits the chillers to perform the next defrosting operation in descending order of the number of defrosting operation requests or request time.

Description

  The present invention relates to a chiller system in which a plurality of heat pump chillers that adjust the temperature of a circulating fluid for temperature control as a heat medium by the heat of condensation or evaporation of refrigerant are connected.

  In a heat pump, when a refrigerant-air heat exchanger that exchanges heat between refrigerant and air acts as an evaporator, frost attached to piping in the refrigerant-air heat exchanger is removed depending on conditions such as outside air temperature. The structure which performs defrost operation (defrost operation) is known conventionally (for example, refer to patent documents 1). Specifically, Patent Document 1 discloses a configuration in which, during the defrost operation, the expansion valve for the indoor heat exchanger is fully closed and the refrigerant is evaporated by absorbing heat from the engine cooling water with the waste heat recovery unit without flowing the refrigerant through the indoor heat exchanger. Disclosure.

  On the other hand, the heat pump chiller that adjusts the temperature of the circulating fluid for temperature control (for example, for air conditioning) as the heat medium by the heat of condensation or evaporation of the refrigerant is also attached to the pipe in the refrigerant-air heat exchanger. In the chiller system in which a plurality of heat pump chillers are connected, the temperature of the circulating fluid is not adjusted during the defrost operation. If a predetermined number or more of chillers (especially all chillers) perform the defrost operation at the same time, the temperature of the circulating fluid cannot be adjusted sufficiently (or at all).

  In this regard, Patent Document 2 discloses that when there is a request for defrosting operation from each chilling unit (chiller), a predetermined number of chilling units are executed so that only a preset number of chilling units (chillers) simultaneously execute the defrosting operation. A defrost permission signal is output for each (chiller) (see paragraph 0104 of Patent Document 2). When the number of simultaneous defrost operations is two or more, the defrost permission signal is output until the number of possible defrost request signals is reached. Is output (see paragraph 0111 of Patent Document 2). That is, Patent Document 2 discloses a configuration in which defrost operation is permitted on a first-come-first-served basis up to the possible number of simultaneous defrost operations.

Japanese Patent No. 4257351 JP-A-10-122604

  However, Patent Document 2 discloses a configuration that permits defrost operation on a first-come-first-served basis up to the possible number of simultaneous defrost operations, but does not disclose the priority order of chillers waiting for defrost operation.

  Therefore, the present invention is a chiller system in which a plurality of heat pump chillers are connected, and when defrosting operation is permitted on a first-come-first-served basis up to a predetermined number, the priority order of chillers waiting for defrosting operation is determined. The purpose is to provide a chiller system that can be used.

  In order to solve the above-mentioned problem, the present invention is a chiller system in which a plurality of heat pump chillers that adjust the temperature of the circulating fluid for temperature adjustment as a heat medium by the heat of condensation or evaporation of the refrigerant are connected, Any one of the plurality of chillers is designated as a chiller of the main unit, and among the plurality of chillers, a chiller requiring defrost operation requests the defrost operation from the chiller of the main unit. The chiller of the master unit permits the defrosting operation in a first-come-first-served basis up to a predetermined number of chillers that have requested the defrosting operation, and the chiller waiting for the defrosting operation is in a predetermined cycle. When the chiller of the master unit requests the defrost operation and the chiller of the master unit has a plurality of chillers waiting for the defrost operation, Providing a chiller system and permits the next of the defrost operation in order of determined number or request time.

  In the present invention, the chiller of the master unit may be configured to permit the next defrosting operation in order of increasing or decreasing identification number for chillers having the same number of requests or the same time of the defrosting operation.

  The present invention is also a chiller system in which a plurality of heat pump chillers that adjust the temperature of the circulating fluid for temperature control as a heat medium by the heat of condensation or evaporation of the refrigerant are connected to the plurality of chillers. A control mechanism that performs operation control on the chiller, and a chiller that requires defrost operation among the plurality of chillers requests the control mechanism to perform the defrost operation, and the control mechanism requests the defrost operation. Among the chillers, the defrost operation is permitted in a first-come-first-served basis to a predetermined number of chillers, and the chiller waiting for the defrost operation requests the control mechanism for the defrost operation at a predetermined cycle, and the control When there are a plurality of chillers waiting for the defrost operation, the mechanism determines the number of requests or the time required for the defrost operation in descending order. Also provides a chiller system and permits the defrost operation.

  According to the present invention, in a chiller system in which a plurality of heat pump chillers are connected, it is possible to determine the priority order of chillers that are waiting for defrost operation when permitting defrost operation on a first-come-first-served basis up to a predetermined number of units. Become.

1 is a system diagram showing a schematic configuration of a chiller system according to an embodiment of the present invention. It is a schematic block diagram of one chiller in a chiller system. It is a schematic block diagram of the chiller which shows the cooling operation state which is performing the cooling operation. It is a schematic block diagram of the chiller which shows the heating operation state which is performing heating operation. It is a schematic block diagram of the chiller which shows the defrost operation state which is performing defrost operation. In the chiller system where the number of chillers is 8, the request for defrost operation from each chiller to the chiller of the master unit, and the permission or prohibition of defrost operation for each chiller of the master unit chiller It is a conceptual diagram showing an example, and the defrosting operation of two chillers that were earlier than the first chiller and allowed the defrosting operation of the two chillers that were earlier in the first-come-first-served basis that the chiller of the parent machine requested the defrosting operation. It is a figure which shows the state which has prohibited. In the chiller system where the number of chillers is 8, the request for defrost operation from each chiller to the chiller of the master unit, and the permission or prohibition of defrost operation for each chiller of the master unit chiller FIG. 7 is a conceptual diagram showing an example in which the chiller of the master unit performs defrosting operation of two chillers that are in standby state in which the number of requests is large in order of the number of times of defrosting operation after the defrosting operation of the two chillers shown in FIG. It is a figure which shows the state which has permitted and the defrost driving | operation of one chiller which was smaller than two chillers is prohibited. In the chiller system where the number of chillers is 8, the request for defrost operation from each chiller to the chiller of the master unit, and the permission or prohibition of defrost operation for each chiller of the master unit chiller It is a conceptual diagram which shows an example, Comprising: It is a figure which shows the state which the chiller of a main | base station has permitted the defrost operation of one remaining chiller after completion | finish of the defrost operation of two chillers shown in FIG. In the example shown in FIGS. 6-8, it is a graph which shows the temperature control capability of a chiller system, and the timing chart of the driving | running state of each chiller. It is a flowchart which shows the flow of an example of the control action by the defrost control to each chiller of the chiller of a main | base station.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a system diagram showing a schematic configuration of a chiller system 1 according to an embodiment of the present invention.

  The chiller system 1 shown in FIG. 1 is configured such that a plurality of heat pump chillers 100 are connected in parallel. Hereinafter, the heat pump chiller may be simply referred to as a chiller.

  Specifically, the chiller system 1 includes a plurality of chillers 100 (1) to 100 (n) (n is an integer of 2 or more) and a circulating fluid circuit 200. The chillers 100 (1) to 100 (n) have the same configuration. Therefore, the rated outputs of the chillers 100 (1) to 100 (n) are all the same. In addition, in the following description, the code | symbol 100 may be attached | subjected only with respect to each chiller 100 (1) -100 (n).

  The chiller system 1 includes a circulating fluid circuit 200 that is laid in a temperature control target area (for example, an air conditioning target area) that is not shown in the figure and that circulates a circulating fluid for temperature control (for example, for air conditioning) as a heat medium. Circulation pumps 300 (1) to 300 (n) that are provided for each of the plurality of chillers 100 (1) to 100 (n) and circulate the circulating fluid in the circulating fluid circuit 200. ) To 300 (n), the temperature of the circulating fluid flowing in the circulating fluid circuit 200 is adjusted. Here, the circulating fluid may be any fluid as long as it acts as a heat medium, and representatively, water can be exemplified. However, it is not limited thereto, and the circulating fluid may be, for example, water containing an antifreeze.

  The circulating fluid circuit 200 includes an inflow trunk pipe 210 that flows the circulating fluid in a direction of flowing into the plurality of chillers 100 (1) to 100 (n), and a circulating fluid from the inflow trunk pipe 210 that includes the plurality of chillers 100 (1 ) To 100 (n), and the outflow stems 211 (1) to 211 (n) to be diverted respectively, and the outflow stem to flow the circulating liquid in the direction of flowing out from the plurality of chillers 100 (1) to 100 (n). It is comprised with the pipe | tube 220 and the outflow branch pipes 221 (1) -221 (n) which each join the circulating fluid from several chillers 100 (1) -100 (n) toward the outflow trunk pipe 220, respectively. .

  Specifically, the inflow branch pipes 211 (1) to 211 (n) are respectively branched portions corresponding to the chillers 100 (1) to 100 (n) of the inflow trunk pipe 210 and the chillers 100 (1) to 100 (1) to 100 (n). 100 (n) circulating fluid inflow side is connected. The outflow branch pipes 221 (1) to 221 (n) are respectively connected to the circulating fluid outflow side of each of the chillers 100 (1) to 100 (n) and the chillers 100 (1) to 100 (n) of the outflow trunk pipe 220. ) Is connected to the junction corresponding to. One of the inflow branch pipes 211 (1) to 211 (n) and the outflow branch pipes 221 (1) to 221 (n) (in this example, the outflow branch pipes 221 (1) to 221 (n)) Circulation pumps 300 (1) to 300 (n) for circulating the circulating fluid in the circulating fluid circuit 200 are provided.

  In the chiller system 1 having such a configuration, the circulating fluid circulated by the circulation pumps 300 (1) to 300 (n) is passed from the inflow trunk pipe 210 through the inflow branch pipes 211 (1) to 211 (n). Each chiller 100 (1) to 100 (n) is distributed, and the temperature is adjusted in each chiller 100 (1) to 100 (n). The circulating fluid whose temperature is adjusted is joined from each chiller 100 (1) to 100 (n) to the outflow trunk 220 through each outflow branch 221 (1) to 221 (n). It circulates through the temperature control area (for example, the air conditioning area). The load sides of the inflow trunk pipe 210 and the outflow trunk pipe 220 are connected via, for example, a heat exchanger (not shown) to form a closed circuit.

  FIG. 2 is a schematic block diagram of one chiller 100 in the chiller system 1. In FIG. 2, one inflow branch pipe 211 of the inflow branch pipes 211 (1) to 211 (n) is shown, and one outflow branch of the outflow branch pipes 221 (1) to 221 (n). A pipe 221 is shown and one of the circulation pumps 300 (1) -300 (n) is shown.

  The chiller 100 drives the compressor 10 that compresses the refrigerant, and adjusts the temperature of the circulating fluid by the heat of condensation or evaporation of the refrigerant.

  That is, the chiller 100 includes a compressor 10 that sucks and discharges refrigerant, a refrigerant-air heat exchanger 20 that exchanges heat between the refrigerant and air (specifically, outside air), and a refrigerant-air heat exchanger 20. Refrigerant-air heat exchanger fan 30 for expansion, an expansion valve 40 for expanding the refrigerant compressed by the compressor 10, a refrigerant-circulating liquid heat exchanger 50 for exchanging heat between the circulating liquid and the refrigerant, and compression The engine 60 that drives the machine 10 and the engine exhaust heat recovery unit 70 that recovers the exhaust heat of the engine 60 are provided, and a heating operation, a cooling operation, or a defrost operation (defrosting operation) described later can be performed. . In this example, the expansion valve 40 includes a first expansion valve 41 that can be closed and a second expansion valve 42 that can be closed.

  The compressor 10 may be a unit in which a plurality of compressors are connected in parallel. Similarly, the refrigerant-air heat exchanger 20 is a unit in which a plurality of refrigerant-air heat exchangers are connected in parallel. There may be.

  Specifically, the chiller 100 further includes a refrigerant circuit 110 for circulating the refrigerant, a cooling water circuit 120 for circulating engine cooling water for cooling the engine 60, a circulation pump 130 for the cooling water circuit 120, and a control device 140. I have.

  The refrigerant circuit 110 is provided with a compressor 10, a refrigerant-air heat exchanger 20, a refrigerant-circulated liquid heat exchanger 50, an expansion valve 40, and an engine exhaust heat recovery unit 70.

  The refrigerant circuit 110 includes a four-way valve 111, a bridge circuit 112, a high-pressure gas refrigerant path 113a, a first low-pressure gas refrigerant path 113b, a first gas refrigerant path 113c, a first refrigerant path 113d, a high-pressure liquid refrigerant path 113e, and a first low-pressure gas. A liquid two-phase refrigerant path 113f, a second refrigerant path 113g, a second gas refrigerant path 113h, a second low-pressure gas-liquid two-phase refrigerant path 113i, and a second low-pressure gas refrigerant path 113j are provided.

  The four-way valve 111 connects the inlet (lower side in FIG. 2) and one connection port (left side in FIG. 2) and the other connection port (FIG. 2) in response to an instruction signal from the control device 140. The first connection state (the state shown in FIG. 2) connecting the outlet (upper side in FIG. 2), the inlet and the other connection port, and one connection port It is set as the structure switched to the 2nd connection state which connects an outflow port. Thereby, the four-way valve 111 can switch the flow direction of a refrigerant | coolant.

  The bridge circuit 112 includes four check valves (a first check valve 112a, a second check valve 112b, a third check valve 112c, and a fourth check valve 112d), and two check valves ( A first check valve row 1121 including a first check valve 112a and a second check valve 112b), and a second check valve including a remaining two check valves (a third check valve 112c and a fourth check valve 112d). 2 check valve trains 1122.

  The first check valve row 1121 is configured such that the first check valve 112a and the second check valve 112b are connected in series so that the refrigerant flows in the same direction. The second check valve row 1122 is configured such that the third check valve 112c and the fourth check valve 112d are connected in series so that the refrigerant flows in the same direction. The first check valve row 1121 and the second check valve row 1122 are connected in parallel so that the refrigerant flows in the same direction.

  In the bridge circuit 112, a connection point between the first check valve 112a and the second check valve 112b is a first intermediate connection point P1, and between the first check valve 112a and the third check valve 112c. Is the outflow connection point P2, the connection point between the third check valve 112c and the fourth check valve 112d is the second intermediate connection point P3, and the second check valve 112b and the fourth check valve A connection point between the stop valve 112d and the stop valve 112d is an inflow connection point P4.

  The high-pressure gas refrigerant path 113 a connects the discharge port of the compressor 10 and the inflow port of the four-way valve 111. The first low-pressure gas refrigerant path 113 b connects the outlet of the four-way valve 111 and the suction port of the compressor 10. The first gas refrigerant path 113 c connects one connection port of the four-way valve 111 and one connection port of the refrigerant-air heat exchanger 20. The first refrigerant path 113 d connects the other connection port of the refrigerant-air heat exchanger 20 and the first intermediate connection point P <b> 1 of the bridge circuit 112. The high-pressure liquid refrigerant path 113e connects the outflow connection point P2 of the bridge circuit 112 and one side of the expansion valve 40 (specifically, the first expansion valve 41 and the second expansion valve 42). The first low-pressure gas-liquid two-phase refrigerant path 113f connects the other side of the first expansion valve 41 constituting the expansion valve 40 and the inflow connection point P4 of the bridge circuit 112. The second refrigerant path 113g connects the second intermediate connection point P3 of the bridge circuit 112 and one refrigerant connection port of the refrigerant-circulating fluid heat exchanger 50. The second gas refrigerant path 113 h connects the other refrigerant connection port of the refrigerant-circulated liquid heat exchanger 50 and the other connection port of the four-way valve 111. The second low-pressure gas-liquid two-phase refrigerant path 113 i connects the other side of the second expansion valve 42 constituting the expansion valve 40 and the refrigerant inlet of the engine exhaust heat recovery device 70. The second low-pressure gas refrigerant path 113j connects the refrigerant outlet of the engine exhaust heat recovery unit 70 and a junction P5 in the middle of the first low-pressure gas refrigerant path 113b. Here, the downstream side (compressor 10 side) of the junction P5 in the first low-pressure gas refrigerant path 113b is a junction path 113b1.

  Both the first expansion valve 41 and the second expansion valve 42 can be adjusted in opening degree by an instruction signal from the control device 140. Thereby, the first expansion valve 41 and the second expansion valve 42 can adjust the circulation amount of the refrigerant in the refrigerant circuit 110. Specifically, the first expansion valve 41 and the second expansion valve 42 are each formed by connecting a plurality of expansion valves that can be closed in parallel. By doing so, the first expansion valve 41 and the second expansion valve 42 can adjust the circulation amount of the refrigerant in the refrigerant circuit 110 by combining the expansion valves to be opened.

  In the present embodiment, chiller 100 further includes an oil separator 81, an accumulator 82, and a receiver 83.

  The oil separator 81 is provided in the high-pressure gas refrigerant path 113a, and separates the lubricating oil of the compressor 10 contained in the refrigerant and compresses the separated lubricating oil through a valve 81a (specifically, an electromagnetic valve). Return to machine 10. The accumulator 82 is provided in the merging path 113b1 of the first low-pressure gas refrigerant path 113b, and is evaporated by the refrigerant-circulating liquid heat exchanger 50 acting as an evaporator or the refrigerant-air heat exchanger 20 acting as an evaporator. The refrigerant liquid that did not run out is separated. The receiver 83 is provided in the high-pressure liquid refrigerant path 113e, and temporarily stores the high-pressure liquid refrigerant from the bridge circuit 112.

  The coolant circuit 120 constitutes an engine coolant path for cooling the engine 60, and includes a first thermostat type switching valve 121, a second thermostat type switching valve 122, a radiator 123, an outflow path 124a, An inflow path 124b and a first path 124c to a fifth path 124g are provided.

  The outflow path 124a connects the outlet of the engine 60 and the inlet (lower side in FIG. 2) of the first thermostat type switching valve 121. The inflow path 124 b connects the outlet of the radiator 123 and the inlet of the engine 60. The first path 124c connects one outlet (upper side in FIG. 2) of the first thermostat type switching valve 121 and an inlet (left side in FIG. 2) of the second thermostat type switching valve 122. The second path 124 d connects the other outlet (the right side in FIG. 2) of the first thermostat type switching valve 121 and the inlet of the radiator 123. The third path 124e connects one outlet (the upper side in FIG. 2) of the second thermostat type switching valve 122 and the cooling water inlet of the engine exhaust heat recovery device 70. The fourth path 124f connects the other outlet (the right side in FIG. 2) of the second thermostat type switching valve 122 and the junction P6 in the middle of the inflow path 124b. The fifth path 124g connects the cooling water outlet of the engine exhaust heat recovery unit 70 and the junction P7 upstream of the junction P6 of the inflow path 124b. Circulation pump 130 is provided between the inlet of engine 60 and junction P6 in inflow path 124b. Circulation pump 130 causes engine coolant to circulate in coolant circuit 120 in response to an instruction signal from control device 140. The engine exhaust heat recovery device 70 belongs to both the refrigerant circuit 110 and the coolant circuit 120.

  The first thermostat type switching valve 121 directs the engine cooling water from the engine 60 to the second thermostat type switching valve 122 when the temperature of the engine cooling water is lower than a predetermined first temperature (for example, 71 ° C.). On the other hand, when the engine coolant is equal to or higher than the first temperature, the engine coolant from the engine 60 is caused to flow toward the radiator 123. Thereby, the cooling water circuit 120 circulates the engine cooling water toward the second thermostat type switching valve 122 when the engine cooling water is lower than the first temperature, while the engine cooling water is higher than the first temperature. The engine cooling water can be circulated toward the radiator 123.

  The second thermostat type switching valve 122 is configured to cool the engine from the first thermostat type switching valve 121 when the temperature of the engine cooling water is lower than a predetermined second temperature (for example, 60 ° C.) lower than the first temperature. While water flows toward both the engine exhaust heat recovery unit 70 and the junction P6 of the inflow path 124b, when the temperature is equal to or higher than the second temperature, the engine coolant from the first thermostat type switching valve 121 is used as the engine exhaust heat recovery unit. It is designed to flow toward 70. As a result, when the engine coolant is lower than the second temperature, the coolant circuit 120 circulates the engine coolant toward the junction P6 of the engine exhaust heat recovery unit 70 and the inflow path 124b, while at the second temperature or higher. When the temperature is lower than the first temperature, the engine coolant can be circulated toward the engine exhaust heat recovery unit 70.

  The temperature of the engine coolant can be detected by a temperature sensor (not shown) provided in the coolant circuit 120.

  The inflow branch pipe 211 constituting the circulation liquid circuit 200 connects the circulation liquid inlet of the refrigerant-circulation liquid heat exchanger 50 and the branch portion corresponding to the chiller 100 of the inflow trunk pipe 210 (see FIG. 1). The outflow branch pipe 221 constituting the circulation liquid circuit 200 connects the circulation liquid outlet of the refrigerant-circulation liquid heat exchanger 50 and a junction corresponding to the chiller 100 of the outflow trunk pipe 220 (see FIG. 1). The refrigerant-circulating fluid heat exchanger 50 belongs to both the refrigerant circuit 110 and the circulating fluid circuit 200.

  The compressor 10 is connected to the engine 60 via the clutch 11. The clutch 11 takes a connected state in which the driving force is transmitted from the engine 60 to the compressor 10 and a disconnected state in which the transmission of the driving force from the engine 60 to the compressor 10 is interrupted by an instruction signal from the control device 140. It has become.

  The chiller 100 further includes a first pressure sensor 151, a first temperature sensor 161, a second pressure sensor 152, a second temperature sensor 162, and a rotation speed sensor 170.

  The first pressure sensor 151 and the first temperature sensor 161 are respectively provided in the merge path 113b1, and detect the pressure and temperature of the refrigerant in the merge path 113b1. The second pressure sensor 152 and the second temperature sensor 162 are provided in the second low-pressure gas refrigerant path 113j, respectively, and detect the pressure and temperature of the refrigerant in the second low-pressure gas refrigerant path 113j. The rotation speed sensor 170 is provided in the engine 60 and detects the rotation speed of the engine 60.

  The circulating fluid circuit 200 includes an inflowing circulating fluid temperature sensor 231 and an outflowing circulating fluid temperature sensor 232.

  Specifically, the inflowing circulating liquid temperature sensor 231 is provided in the inflow branch pipe 211, and the temperature of the circulating liquid (specifically, the circulating liquid in the inflow branch pipe 211) that flows into the refrigerant-circulating liquid heat exchanger 50. Is detected. The outflow circulating fluid temperature sensor 232 is provided in the outflow branch 221 and detects the temperature of the circulating fluid flowing out from the refrigerant-circulating fluid heat exchanger 50 (specifically, the circulating fluid in the outflow branch 221). .

  The control device 140 controls driving of the refrigerant circuit 110, the cooling water circuit 120, and the circulating fluid circuit 200 based on detection signals from various sensors. Thereby, the chiller 100 can adjust the temperature of the circulating fluid flowing in the circulating fluid circuit 200.

  Specifically, the control device 140 compresses the refrigerant sucked from the first low-pressure gas refrigerant path 113b by the compressor 10, and discharges the compressed refrigerant to the high-pressure gas refrigerant path 113a. During the cooling operation for performing the cooling operation for cooling the circulating fluid in the circulating fluid circuit 200, the control device 140 causes the four-way valve 111 to communicate with the high-pressure gas refrigerant path 113a and the first gas refrigerant path 113c and to supply the second gas refrigerant path. 113h and the 1st low pressure gas refrigerant path 113b are made into the 1st connection state which connects. Further, the control device 140 communicates the four-way valve 111 with the high-pressure gas refrigerant path 113a and the second gas refrigerant path 113h and the first gas at the time of the heating operation for heating the circulating fluid in the circulating fluid circuit 200. The refrigerant passage 113c and the first low-pressure gas refrigerant passage 113b are brought into a second connection state in which the refrigerant passage 113c communicates with the first low-pressure gas refrigerant passage 113b.

  The refrigerant-air heat exchanger 20 functions as a condenser that radiates and liquefies the refrigerant during the cooling operation, and functions as an evaporator that absorbs and vaporizes the refrigerant during the heating operation. The refrigerant-circulating liquid heat exchanger 50 functions as a cooler that cools the circulating liquid by absorbing heat during the cooling operation, and functions as a heater that heats the circulating liquid by dissipating heat during the heating operation. The engine exhaust heat recovery unit 70 functions as an evaporator that absorbs heat and vaporizes the refrigerant.

  The first expansion valve 41 and the second expansion valve 42 are arranged in parallel on the downstream side of the bridge circuit 112. The first expansion valve 41 adjusts the flow rate of the refrigerant toward the refrigerant-circulating fluid heat exchanger 50 via the bridge circuit 112 during the cooling operation, and the bridge circuit 112 during the heating operation, based on the instruction signal from the control device 140. The flow rate of the refrigerant toward the refrigerant-air heat exchanger 20 is adjusted. The second expansion valve 42 adjusts the flow rate of the refrigerant toward the engine exhaust heat recovery device 70 according to an instruction signal from the control device 140.

  The control device 140 includes a processing unit 141 including a microcomputer such as a CPU (Central Processing Unit), a non-volatile memory such as a ROM (Read Only Memory), and a volatile memory such as a RAM (Randam Access Memory). And have.

  In the control device 140, the processing unit 141 controls the operation of various components by loading a control program stored in advance in the ROM of the storage unit 142 onto the RAM of the storage unit 142 and executing it. .

  In the chiller 100 described above, the temperature of the circulating fluid flowing in the circulating fluid circuit 200 can be adjusted by appropriately performing the cooling operation or the heating operation.

  First, the operation of the cooling operation by the chiller 100 will be described with reference to FIG. 3, and then the operation of the heating operation by the chiller 100 will be described with reference to FIG.

[Cooling operation]
FIG. 3 is a schematic block diagram of the chiller 100 showing a cooling operation state in which the cooling operation is performed.

  In the chiller 100, when performing the cooling operation, the control device 140 switches the four-way valve 111 to the first connection state so that the high-pressure gas refrigerant path 113a and the first gas refrigerant path 113c communicate with each other and the second gas refrigerant path 113h. The first low-pressure gas refrigerant path 113b is communicated. By doing so, the refrigerant in the high-pressure gas state (hereinafter referred to as high-pressure gas refrigerant) discharged from the compressor 10 flows to the refrigerant-air heat exchanger 20 via the oil separator 81.

  The temperature of the high-pressure gas refrigerant flowing through the refrigerant-air heat exchanger 20 is higher than the temperature of the air flowing through the refrigerant-air heat exchanger 20. For this reason, heat moves from the high-pressure gas refrigerant to the air. As a result, the high-pressure gas refrigerant loses heat of condensation and liquefies to become a high-pressure liquid refrigerant (hereinafter referred to as high-pressure liquid refrigerant). That is, in the cooling operation, the refrigerant-air heat exchanger 20 functions as a refrigerant condenser that dissipates heat from the high-pressure gas refrigerant.

  The high-pressure liquid refrigerant flows from the refrigerant-air heat exchanger 20 to the first intermediate connection point P1 of the bridge circuit 112 via the first refrigerant path 113d. Since the first intermediate connection point P1 is located on the outlet side of the second check valve 112b and the inlet side of the first check valve 112a, the high-pressure liquid refrigerant is supplied from the second check valve 112b and the third check valve 112b. It does not flow toward the check valve 112c but flows from the first intermediate connection point P1 to the high-pressure liquid refrigerant path 113e via the first check valve 112a and the outflow connection point P2.

  In performing the cooling operation, the control device 140 opens the first expansion valve 41 so that the high-pressure liquid refrigerant flows to the first expansion valve 41 side, but does not flow to the second expansion valve 42 side. 42 is closed. For this reason, the high-pressure liquid refrigerant passes through the first expansion valve 41 via the receiver 83 on the high-pressure liquid refrigerant path 113e.

  In the first expansion valve 41, the high-pressure liquid refrigerant expands into a low-pressure gas-liquid two-phase refrigerant (hereinafter referred to as a low-pressure gas-liquid two-phase refrigerant). The low-pressure gas-liquid two-phase refrigerant flows from the first low-pressure gas-liquid two-phase refrigerant path 113f to the inflow connection point P4 of the bridge circuit 112. Although the inflow connection point P4 is on the inflow side of the second check valve 112b and the fourth check valve 112d, the high-pressure liquid refrigerant described above flows to the first intermediate connection point P1 and the outflow connection point P2. For this reason, the low-pressure gas-liquid two-phase refrigerant is moved toward the second check valve 112b and the third check valve 112c due to the pressure difference between the high-pressure liquid refrigerant flowing through the first intermediate connection point P1 and the outflow connection point P2. Instead of flowing, it flows from the inflow connection point P4 to the refrigerant-circulating liquid heat exchanger 50 via the fourth check valve 112d, the second intermediate connection point P3, and the second refrigerant path 113g.

  The temperature of the low-pressure gas-liquid two-phase refrigerant flowing to the refrigerant circuit 110 side of the refrigerant-circulating liquid heat exchanger 50 is lower than the temperature of the circulating liquid flowing to the circulating liquid circuit 200 side of the refrigerant-circulating liquid heat exchanger 50. For this reason, heat moves from the circulating fluid to the low-pressure gas-liquid two-phase refrigerant. As a result, the low-pressure gas-liquid two-phase refrigerant is vaporized by obtaining evaporation heat, and becomes a refrigerant in a low-pressure gas state (hereinafter referred to as a low-pressure gas refrigerant). On the other hand, the circulating fluid is cooled by the endothermic action of the refrigerant. That is, in the cooling operation, the refrigerant-circulating fluid heat exchanger 50 functions as a circulating fluid cooler that absorbs heat from the low-pressure gas-liquid two-phase refrigerant.

  Thereafter, the low-pressure gas refrigerant flows from the refrigerant-circulated liquid heat exchanger 50 to the second gas refrigerant path 113h. At this time, since the control device 140 communicates the second gas refrigerant path 113h and the first low-pressure gas refrigerant path 113b by the four-way valve 111, the low-pressure gas refrigerant is an accumulator on the first low-pressure gas refrigerant path 113b. It is sucked into the compressor 10 via 82.

  In the chiller 100, the above-described series of cooling operation is repeated in the same manner.

[Heating operation]
FIG. 4 is a schematic block diagram of the chiller 100 showing a heating operation state in which a heating operation is performed.

  In the chiller 100, when performing the heating operation, the control device 140 switches the four-way valve 111 to the second connection state to connect the high-pressure gas refrigerant path 113a and the second gas refrigerant path 113h and to the first gas refrigerant path 113c. The first low-pressure gas refrigerant path 113b is communicated. By doing so, the high-pressure gas refrigerant discharged from the compressor 10 flows to the refrigerant-circulated liquid heat exchanger 50 via the oil separator 81.

  The temperature of the high-pressure gas refrigerant flowing to the refrigerant circuit 110 side of the refrigerant-circulating liquid heat exchanger 50 is higher than the temperature of the circulating liquid flowing to the circulating liquid circuit 200 side of the refrigerant-circulating liquid heat exchanger 50. For this reason, heat moves from the high-pressure gas refrigerant to the circulating fluid. As a result, the high pressure gas refrigerant loses heat of condensation and liquefies to become a high pressure liquid refrigerant. On the other hand, the circulating fluid is heated by the heat dissipation action of the refrigerant. That is, in the heating operation, the refrigerant-circulating fluid heat exchanger 50 functions as a circulating fluid heater that radiates heat from the high-pressure gas refrigerant.

  The high-pressure liquid refrigerant flows from the refrigerant-circulating liquid heat exchanger 50 to the second intermediate connection point P3 of the bridge circuit 112 via the second refrigerant path 113g. Since the second intermediate connection point P3 is located on the inlet side of the third check valve 112c and on the outlet side of the fourth check valve 112d, the high-pressure liquid refrigerant is supplied from the first check valve 112a and the fourth check valve 112a. It does not flow toward the check valve 112d but flows from the second intermediate connection point P3 to the high-pressure liquid refrigerant path 113e via the third check valve 112c and the outflow connection point P2.

  In performing the heating operation, the control device 140 opens the first expansion valve 41 so that the high-pressure liquid refrigerant flows to the first expansion valve 41 side but does not flow to the second expansion valve 42 side. 42 is closed. For this reason, the high-pressure liquid refrigerant passes through the first expansion valve 41 via the receiver 83 on the high-pressure liquid refrigerant path 113e.

  In the first expansion valve 41, the high-pressure liquid refrigerant expands to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows from the first low-pressure gas-liquid two-phase refrigerant path 113f to the inflow connection point P4 of the bridge circuit 112. The inflow connection point P4 is on the inflow side of the second check valve 112b and the fourth check valve 112d, but the high-pressure liquid refrigerant described above flows to the second intermediate connection point P3 and the outflow connection point P2. For this reason, the low-pressure gas-liquid two-phase refrigerant is moved toward the fourth check valve 112d and the first check valve 112a due to the pressure difference with the high-pressure liquid refrigerant flowing through the second intermediate connection point P3 and the outflow connection point P2. Instead of flowing, it flows from the inflow connection point P4 to the refrigerant-air heat exchanger 20 via the second check valve 112b and the first refrigerant path 113d.

  The temperature of the low-pressure gas-liquid two-phase refrigerant flowing through the refrigerant-air heat exchanger 20 is lower than the temperature of the air flowing through the refrigerant-air heat exchanger 20. For this reason, heat moves from the air to the low-pressure gas-liquid two-phase refrigerant. As a result, the low-pressure gas-liquid two-phase refrigerant is vaporized by obtaining the evaporation heat, and becomes a low-pressure gas refrigerant. That is, in the heating operation, the refrigerant-air heat exchanger 20 functions as a refrigerant evaporator that absorbs heat from the low-pressure gas-liquid two-phase refrigerant.

  Thereafter, the low-pressure gas refrigerant flows from the refrigerant-air heat exchanger 20 to the first gas refrigerant path 113c. At this time, since the control device 140 communicates the first gas refrigerant path 113c and the first low-pressure gas refrigerant path 113b by the four-way valve 111, the low-pressure gas refrigerant is an accumulator on the first low-pressure gas refrigerant path 113b. It is sucked into the compressor 10 via 82.

  In the chiller 100, the above-described series of heating operation is repeated in the same manner.

[Defrost operation]
By the way, when the heating operation is performed, since the low-pressure gas-liquid two-phase refrigerant is supplied to the refrigerant-air heat exchanger 20, the piping in the refrigerant-air heat exchanger 20 is cooled. At this time, frost may adhere to piping in the refrigerant-air heat exchanger 20 depending on conditions such as the outside air temperature. In this case, the chiller 100 performs a defrost operation.

  Next, the operation of the defrost operation by the chiller 100 will be described with reference to FIG.

  FIG. 5 is a schematic block diagram of the chiller 100 showing a defrost operation state in which the defrost operation is performed.

  In the chiller 100, when performing the defrost operation, the control device 140 switches the four-way valve 111 to the first connection state to communicate the high-pressure gas refrigerant path 113a and the first gas refrigerant path 113c and perform the second operation similarly to the cooling operation. The gas refrigerant path 113h communicates with the first low-pressure gas refrigerant path 113b. By doing so, the high-pressure gas refrigerant discharged from the compressor 10 flows to the refrigerant-air heat exchanger 20 via the oil separator 81.

  The high-pressure gas refrigerant flowing in the refrigerant-air heat exchanger 20 loses heat of condensation and liquefies to become a high-pressure liquid refrigerant as in the cooling operation. That is, in the defrost operation, the refrigerant-air heat exchanger 20 functions as a refrigerant condenser that dissipates heat from the high-pressure gas refrigerant.

  Similar to the cooling operation, the high-pressure liquid refrigerant passes from the refrigerant-air heat exchanger 20 via the first refrigerant path 113d, the first intermediate connection point P1, the first check valve 112a, and the outflow connection point P2 of the bridge circuit 112. And flows into the high-pressure liquid refrigerant path 113e.

  In performing the defrost operation, the control device 140 opens the second expansion valve 42 so that the high-pressure liquid refrigerant flows to the second expansion valve 42 side but does not flow to the first expansion valve 41 side, while the first expansion valve 42 41 is closed. For this reason, the high-pressure liquid refrigerant passes through the second expansion valve 42 via the receiver 83 on the high-pressure liquid refrigerant path 113e.

  In the second expansion valve 42, the high-pressure liquid refrigerant expands to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flows from the second low-pressure gas-liquid two-phase refrigerant path 113i to the engine exhaust heat recovery unit 70.

  The temperature of the low-pressure gas-liquid two-phase refrigerant flowing to the refrigerant circuit 110 side of the engine exhaust heat recovery unit 70 is lower than the temperature of the engine cooling water flowing to the cooling water circuit 120 side of the engine exhaust heat recovery unit 70. For this reason, heat moves from the engine coolant to the low-pressure gas-liquid two-phase refrigerant. As a result, the low-pressure gas-liquid two-phase refrigerant is vaporized by obtaining the evaporation heat, and becomes a low-pressure gas refrigerant. That is, in the defrost operation, the engine exhaust heat recovery unit 70 functions as a refrigerant evaporator that absorbs heat from the low-pressure gas-liquid two-phase refrigerant.

  Thereafter, the low-pressure gas refrigerant is sucked into the compressor 10 from the engine exhaust heat recovery device 70 via the second low-pressure gas refrigerant path 113j, the junction P5 of the first low-pressure gas refrigerant path 113b, the junction path 113b1, and the accumulator 82. The

  In the chiller 100, the above-described series of defrosting operations are repeated in the same manner.

  In the defrost operation described above, since the high-pressure gas refrigerant is supplied to the refrigerant-air heat exchanger 20, the piping in the refrigerant-air heat exchanger 20 is heated. As a result, frost attached to the refrigerant-air heat exchanger 20 in the heating operation is removed. Further, in the defrost operation, the low-pressure gas-liquid two-phase refrigerant does not flow to the refrigerant-circulated liquid heat exchanger 50, so that the temperature of the circulating liquid does not decrease due to the refrigerant evaporation.

[Control for each chiller in the chiller system]
By the way, in the chiller system 1 to which a plurality of chillers 100 (1) to 100 (n) are connected, when performing the defrost operation for removing frost attached to the pipe in the refrigerant-air heat exchanger 20, the defrost operation is performed. Since the temperature of the circulating fluid is not adjusted (specifically, heating operation), a predetermined number or more of chillers 100 (especially all chillers 100 (1) to 100 (n)) perform the defrost operation at the same time. In this case, the temperature of the circulating fluid cannot be adjusted sufficiently (or at all).

  In this regard, in the conventional chiller system, as described above, when there is a request for defrost operation from each chiller, only the preset number of chillers execute the defrost operation at the same time, and the number of possible defrost simultaneous operations is 2 In the case of the number of units or more, the defrost operation is permitted on a first-come-first-served basis up to the number of units capable of simultaneous defrost operation (see Patent Document 2), but the configuration is such that the priority order of the chillers waiting for defrost operation is determined. Not.

  From such a viewpoint, the chiller system 1 according to the present embodiment includes a control mechanism that performs the following operation control on each of the chillers 100 (1) to 100 (n).

  That is, in the present embodiment, the control mechanism is an aggregate of the control devices 140 of the chillers 100 (1) to 100 (n), and the control devices 140 (1) to 140 (n) can communicate with each other. It is connected. In the chiller system 1, one of the chillers 100 (1) to 100 (n) is designated as the chiller 100 (i) (i is any integer from 1 to n) as the parent device. ing. The control mechanism is a control device that controls the chillers 100 (1) to 100 (n) as a whole, and the control device may be provided separately from the chillers 100 (1) to 100 (n). .

  Each chiller 100 (1) to 100 (n) performs defrost control of defrost operation in order to remove frost attached to the refrigerant-air heat exchanger 20. For example, the chiller 100 during the heating operation determines that the defrost operation is necessary when the continuous execution time of the heating operation exceeds a predetermined time. Defrost control is prepared to deal with a case where it is determined that defrost operation is necessary. In the defrost control, the defrosting exceeds the predetermined number (the number of permitted simultaneous defrosts that is permitted for the defrost operation in the same period) predetermined for the chiller 100 in the heating operation that has been determined to require the defrost operation. In this control, the defrost operation is executed without limiting the number of simultaneous defrost permitted units.

  In the present embodiment, the simultaneous defrost permitted number is the permitted reference number (4 in this example) as a reference for permitting the defrost operation, which is obtained by subtracting one from the number of connected units to which the chiller 100 is connected. The number obtained by adding 1 to the value obtained by rounding down the decimals of the value divided by the number of units.

  That is, assuming that the number of connected devices is n (n ≧ 2) and the permitted reference number is c, the simultaneous defrost permitted number m can be calculated by the following equation (1).

m = INT [(n−1) / c] +1 Formula (1)
However, “INT” in the expression (1) is a function for truncating the decimal part of the value of the expression [(n−1) / c] in the square brackets.

  For example, when the permitted reference number c is 4, when the number n of connections is 2 or more and 4 or less, the number m of simultaneous defrost permits is 1, and when the number of connections n is 5 or more and 8 or less, the number of simultaneous defrost permits m is two.

  In addition, when a plurality of chillers 100 (1) to 100 (n) (child devices) including the chiller 100 (i) of the parent device determines that the defrost operation is necessary, the chiller 100 that requires the defrost operation is The chiller 100 (i) (specifically, the control device 140 (i)) of the master unit is requested to request defrost operation (specifically, a signal for requesting defrost operation is transmitted). In addition, when the chiller 100 requesting the defrost operation is the chiller 100 (i) itself of the parent device, the chiller 100 (i) of the parent device requests the defrost operation from itself.

  In addition, the chiller 100 (i) of the parent machine performs the defrosting operation on a first-come-first-served basis that requests the defrosting operation up to the number m of simultaneous defrosting permitted among the chillers 100 that have requested the defrosting operation to the chiller 100 (i) of the parent machine. It is configured to permit (specifically, send a signal permitting defrost operation). In addition, when the chiller 100 that receives permission for defrost operation is the chiller 100 (i) of the parent device, the chiller 100 (i) of the parent device receives permission for the defrost operation.

  For example, when the number n of connected chillers 100 is 8, chillers 100 (1), chillers 100 (4), 100 (6) to 100 (100) that have requested defrost operation from the chiller 100 (i) of the master unit. 8), when the defrost operation is requested in the order of chiller 100 (1), chiller 100 (4), 100 (6), 100 (7) and 100 (8), the chiller 100 (i) of the master unit is The defrost operation is permitted in the first-come-first-served order of the chiller 100 (1) and the chiller 100 (4) up to the simultaneous defrost permitted number m (two in this example).

  In each of the chillers 100 (1) to 100 (n), the chiller 100 waiting for the defrost operation is in a predetermined cycle (specifically, every predetermined processing time) with respect to the chiller 100 (i) of the master unit. The defrost operation is requested (specifically, a signal requesting the defrost operation is transmitted).

  Here, the standby chiller 100 requests the chiller 100 (i) of the parent machine to perform the defrost operation, but the chiller 100 (i) of the parent machine does not permit the defrost operation (the operation is not allowed). A chiller that is prohibited.

  When there are a plurality of chillers 100 that are waiting for defrost operation, the chiller 100 (i) of the master unit requires the number of defrost operation requests or the request time (the number of requests in the examples shown in FIGS. 6 to 10 described later). ), The next defrost operation is permitted in descending order. Here, the number of times of defrost operation requested is that the defrost operation is requested from the first request of the defrost operation by the chiller 100 that requires the defrost operation to the latest permission determination of the defrost operation by the chiller 100 (i) of the parent machine. Is the number of times. The required time for the defrost operation is the time required from the initial request for the defrost operation by the chiller 100 that requires the defrost operation to the latest permission determination of the defrost operation by the chiller 100 (i) of the master unit.

  Also, each chiller 100 (1) to 100 (n) is assigned a different identification number (1 to n in this example), and the chiller 100 (i) of the master unit can receive the number of defrost operation requests or The chillers 100 having the same request time are configured to permit the next defrost operation in the order of increasing or decreasing identification numbers (in the order of decreasing numbers in the examples shown in FIGS. 6 to 10).

  FIGS. 6 to 8 show the defrost operation of each chiller 100 (1) to 100 (8) from the chiller 100 (1) to 100 (8) to the chiller 100 (i) of the master unit in the chiller system 1 in which the number n of chillers 100 connected is eight. It is a conceptual diagram which shows an example of the state which is permitting or prohibiting a defrost driving | operation with respect to each chiller 100 (1) -100 (8) of the chiller 100 (i) of a main | base station and a request | requirement.

  In the examples of FIGS. 6 to 8, among the chillers 100 (1) to 100 (8), the operating capacity of six chillers 100 is sufficient for the load capacity, and therefore, two chillers 100 ( 3) An example in which heating operation is performed with six chillers 100 (1), 100 (2), 100 (4), and 100 (6) to 100 (8), while 100 (5) is stopped. ing. Specifically, among the chillers 100 (1), 100 (2), 100 (4), and 100 (6) to 100 (8) that perform the heating operation, it is determined that the defrost operation is necessary, and the chiller of the parent device Of the chillers 100 (1), 100 (4), 100 (6) to 100 (8) that requested the defrost operation for 100 (i), the top two chillers 100 in the first-come-first-served basis that requested the defrost operation. The order is the order of the chiller 100 (1) and the chiller 100 (4), and the order of the remaining chillers 100 (6) to 100 (8) is the order of the chiller 100 (6), An example in which the chiller 100 (8) and the chiller 100 (7) are arranged in this order is shown.

  That is, FIG. 6 shows that two chillers 100 (1) and 100 (4), which were earlier in the first-come-first-served basis in which the chiller 100 (i) of the parent machine requested the defrost operation, are permitted, and the two chillers 100 are allowed. (1) The state which has prohibited the defrost driving | operation of three chillers 100 (6) -100 (8) later than 100 (4) is shown.

  FIG. 7 shows that the chiller 100 (i) of the master unit is in a standby state in which the number of requests is large in the order of the number of requests for defrost operation after the defrost operation of the two chillers 100 (1) and 100 (4) shown in FIG. Allow defrost operation of two chillers 100 (6) and 100 (8), and prohibit defrost operation of one chiller 100 (7) that is smaller than two chillers 100 (6) and 100 (8) This indicates a state in which the standby state is continued.

  Further, FIG. 8 shows that the chiller 100 (i) of the master unit performs the defrosting operation of the remaining chiller 100 (7) after the defrosting operation of the two chillers 100 (6) and 100 (8) shown in FIG. Indicates the permitted state.

  FIG. 9 is a graph showing a temperature control capability of the chiller system 1 and timing charts of the operating states of the chillers 100 (1) to 100 (8) in the examples shown in FIGS.

  In FIG. 9, thermo-on means a state where the compressor 10 is operating, and thermo-off means a state where the compressor 10 is stopped. Further, defrost operation on means a state in which the defrost operation is being performed, and defrost operation off means a state in which the defrost operation is not being performed. In the example shown in FIGS. 6 to 9, the chillers 100 (1), 100 (2), 100 (4), and 100 (6) to 100 (8) in the thermo-on state perform the heating operation when the defrost operation is off. When the defrost operation is on, the defrost operation is performed. In addition, the chillers 100 (3) and 100 (5) that are originally stopped are stopped when the thermostat is off, and the heating operation is performed when the thermostat is on.

(About the control action of each chiller of the master unit)
Next, the control operation of each chiller 100 (1) to 100 (n) of the chiller 100 (i) of the master unit will be described below with reference to the examples shown in FIGS.

  FIG. 10 is a flowchart showing a flow of an example of a control operation by defrost control of each of the chillers 100 (1) to 100 (n) of the chiller (i) of the parent device.

  In the chiller system 1, of the eight chillers 100 (1) to 100 (8), the two chillers 100 (3) and 100 (5) are stopped, and the six chillers 100 (1) and 100 (100) are stopped. When (2), 100 (4), 100 (6) to 100 (8) are performing the heating operation (see α1 in FIG. 9), the chillers 100 (1), 100 (2), 100 (4), 100 (6) to 100 (8) determine whether or not the defrost operation is necessary (step S1). Based on the determination result, five chillers 100 (1), 100 out of the six chillers 100 (1), 100 (2), 100 (4), 100 (6) to 100 (8) during the heating operation. When (4), 100 (6) -100 (8) needs to perform defrost operation, chillers 100 (1), 100 (4), 100 (6) -100 (8) that require defrost operation are: Defrost request flags FLa (1), FLa (4), FLa (6) to FLa (8) are turned on (see FIG. 6), and a defrost operation is requested to the chiller 100 (i) of the master unit (step S2). ). Here, defrost request flags FLa (1) to FLa (8) and defrost permission flags FLb (1) to FLb (8) to be described later are OFF in the initial state.

  Next, the chiller 100 (i) of the parent device sets the chiller 100 (i) of the parent device in the defrost permission flags FLb (1) to FLb (8) corresponding to the chillers 100 (1) to 100 (8). For the chiller 100 that requests defrost operation (in this example, chillers 100 (1), 100 (4), 100 (6) to 100 (8)), the number of simultaneous defrost allowed in the first-come-first-served basis that requested defrost operation. Defrost permission flags FLb (1), FLb (4) of m (two in this example) chillers 100 (in this example, chillers 100 (1), 100 (4)) are turned on (see FIG. 6). The defrost operation is permitted to the chillers 100 (1) and 100 (4) for the simultaneous defrost permitted number (two in this example) in the first-come-first-served order that the operation is requested (step S3).

  Then, the two chillers 100 (1) and 100 (4) for which the defrost operation is permitted are changed from the heating operation to the defrost operation (step S4), and the chiller 100 during the heating operation is reduced from two to six. Since the chillers 100 (2) and 100 (6) to 100 (8) are used, the air capacity is reduced (see α2 in FIG. 9). For this reason, the chiller 100 (i) of the master unit performs the heating operation with the two stopped chillers 100 (3) and 100 (5) being thermo-on, and performing the heating operation. Two chillers 100 (2), 100 (3), 100 (5), and 100 (6) to 100 (8) are added from the pedestal (see α3 in FIG. 9).

  Next, when the chillers 100 (1) and 100 (4) in the defrost operation are in the defrost operation (step S5: No), the chillers 100 (6) to 100 (8) in the defrost operation standby are The defrost operation is requested to the chiller 100 (i) of the master unit at a predetermined cycle (step S6). On the other hand, in the chillers 100 (1) and 100 (4) during the defrost operation, when the frost is removed and the defrost operation becomes unnecessary (step S5: Yes), the defrost operation is terminated (step S7), and the defrost request flag FLa (1), FLa (4) is turned off, and chiller 100 (i) of the master unit turns off defrost permission flags FLb (1), FLb (4) (see FIG. 7).

  Then, the two chillers 100 (1) and 100 (4) whose defrost request flags FLa (1) and FLa (4) are turned off return from the defrost operation to the heating operation, and the chiller 100 during the heating operation starts from six. Since the two chillers increase to eight chillers 100 (1) to 100 (8), the air capacity increases (see α4 in FIG. 9). For this reason, the chiller 100 (i) of the master unit is stopped by thermo-offing the two chillers 100 (3) and 100 (5) that are in the heating operation that are thermo-on even though they are originally stopped. The chiller 100 during the heating operation is reduced from 8 to 2 to 6 chillers 100 (1), 100 (2), 100 (4), 100 (6) to 100 (8) (in FIG. 9). α5).

  Next, the process proceeds to step S10 through step S8 (step S8: Yes) and step S9 (step S9 Yes), and the chiller 100 (i) of the parent device performs defrost operation on the chiller 100 (i) of the parent device. Requesting chillers 100 (in this example, chillers 100 (6) to 100 (8)) are ordered in descending order of the number of requests for defrost operation (descending order), and the chillers 100 having the same number of requests are ordered in ascending order of identification numbers ( Ascending order) (step S10), the order of the chillers 100 (6) to 100 (8) is changed to the order of the chiller 100 (6), the chiller 100 (8), and the chiller 100 (7). In this example, since the number of requests for the chiller 100 (8) is larger than the number of requests for the chiller 100 (7), the order of the chillers 100 (6) to 100 (8) is chiller 100 (6), chiller 100. (8) and chiller 100 (7) in this order. For example, when chiller 100 (8) and chiller 100 (7) have the same number of requests, the identification number of chiller 100 (8) is “8”. On the other hand, since the identification number of the chiller 100 (7) is “7”, the order of the chillers 100 (6) to 100 (8) is chiller 100 (6), chiller 100 (7), and chiller 100 ( 8).

  After that, the chiller 100 (i) of the parent device is in response to the chiller 100 (i) of the parent device in the defrost permission flags FLb (1) to FLb (8) corresponding to the chillers 100 (1) to 100 (8). Among the chillers 100 requesting the defrost operation (in this example, chillers 100 (6) to 100 (8)), the chillers having a large number of requests in the order of the number of requests for the defrost operation and the same number of requests have a small identification number. The defrost permission flags FLb (6) and FLb (8) of the chillers 100 (the chillers 100 (6) and 100 (8) in this example) for the simultaneous defrost permission number m (two in this example) are turned on (FIG. 7). See), chillers for the number of allowed simultaneous defrosts (two in this example) with a small identification number between chillers with the same number of requests in the order of the number of requests for defrost operation. 100 (6), to allow the defrost operation for 100 (8) (step S11).

  Then, the two chillers 100 (6) and 100 (8) for which the defrosting operation is permitted are changed from the heating operation to the defrosting operation (step S4), and the chiller 100 during the heating operation is reduced from two to four. Since the chillers 100 (1), 100 (2), 100 (4), and 100 (7) are provided, the air capacity is reduced (see α6 in FIG. 9). For this reason, the chiller 100 (i) of the master unit performs the heating operation with the two stopped chillers 100 (3) and 100 (5) being thermo-on, and performing the heating operation. Two chillers 100 (1) to 100 (5), 100 (7) are added from the pedestal (see α7 in FIG. 9).

  Next, when the chillers 100 (6) and 100 (8) in the defrost operation are in the defrost operation (step S5: No), the chiller 100 (7) in the defrost operation standby is set to the parent cycle at a predetermined cycle. The defrosting operation is requested to the chiller 100 (i) of the machine (step S6). On the other hand, in the chillers 100 (1) and 100 (4) during the defrost operation, when the frost is removed and the defrost operation becomes unnecessary (step S5: Yes), the defrost operation is terminated (step S7), and the defrost request flag FLa (6), FLa (8) is turned off, and chiller 100 (i) of the master unit turns off defrost permission flags FLb (6), FLb (8) (see FIG. 8).

  Then, the two chillers 100 (6) and 100 (8) whose defrost request flags FLa (6) and FLa (8) are turned off return to the heating operation from the defrost operation, and the chiller 100 during the heating operation starts from six. Since the two chillers increase to eight chillers 100 (1) to 100 (8), the air capacity increases (see α8 in FIG. 9). For this reason, the chiller 100 (i) of the master unit is stopped by thermo-offing the two chillers 100 (3) and 100 (5) that are in the heating operation that are thermo-on even though they are originally stopped. The chiller 100 during the heating operation is reduced from 8 to 2 to 6 chillers 100 (1), 100 (2), 100 (4), 100 (6) to 100 (8) (in FIG. 9). α9).

  Next, the process proceeds to step S12 through step S8 (step S8: Yes) and step S9 (step S9: No), and the chiller 100 (i) of the parent device is transferred to each chiller 100 (1) to 100 (8). In the corresponding defrost permission flags FLb (1) to FLb (8), the remaining one chiller 100 (in this example, chiller 100 (7)) requesting the defrost operation from the chiller 100 (i) of the master unit. ) Defrost permission flag FLb (7) is turned on (see FIG. 8), and the remaining one chiller 100 (7) is permitted to defrost (step S12).

  Then, the one chiller 100 (7) in which the defrost operation is permitted is changed from the heating operation to the defrost operation (step S4), and the chiller 100 during the heating operation is reduced from one to six and five chillers 100 ( 1), 100 (2), 100 (4), 100 (6), 100 (8), the air capacity decreases (see α10 in FIG. 9). For this reason, the chiller 100 (i) of the master unit performs the heating operation with one chiller 100 (in this example, the chiller 100 (3)) that is thermo-off turned on the thermo-on, and the chiller 100 during the heating operation is operated. Is increased from 5 to 1 to obtain 6 chillers 100 (1) to 100 (4), 100 (6), 100 (8) (see α11 in FIG. 9).

  Next, in the chiller 100 (7) during the defrost operation, when the frost is removed and the defrost operation becomes unnecessary (step S5: Yes), the defrost operation is terminated (step S7), and the defrost request flag FLa (7) is set. The master unit chiller 100 (i) turns off the defrost permission flag FLb (7).

  Then, one chiller 100 (7) with the defrost request flag FLa (7) turned off returns from the defrost operation to the heating operation, and the number of chillers 100 during the heating operation increases by one from six to seven chillers 100 ( 1) to 100 (4) and 100 (6) to 100 (8), the air capacity increases (see α12 in FIG. 9). For this reason, the chiller 100 (i) of the master unit is stopped by turning off the one chiller 100 (3) that is in the heating operation, which is thermo-on in spite of being stopped, by thermo-off. The chiller 100 is reduced from seven to one to obtain six chillers 100 (1), 100 (2), 100 (4), and 100 (6) to 100 (8) (see α13 in FIG. 9).

  Then, when there is no chiller 100 waiting for the defrost operation (step S8: No), the defrost control is terminated.

  In the examples shown in FIGS. 6 to 10, the number of chillers 100 is eight. However, the number of chillers 100 is not limited thereto, and the number of chillers 100 may be 2 to 7 or 9 or more. Good.

  Further, in the example shown in FIGS. 6 to 10, when there are a plurality of chillers waiting for defrost operation, the next defrost operation is permitted in order of the number of requests, but the next time in the order of request time. The defrosting operation may be permitted.

  Further, in the example shown in FIGS. 6 to 10, the chiller 100 (i) of the master unit permits the next defrost operation for the chillers 100 having the same defrost operation request count in ascending order of the identification number. However, the next defrost operation may be permitted in descending order of the identification number.

(About this embodiment)
As described above, according to the chiller system 1 according to the present embodiment, the control mechanism (in this example, the chiller 100 (i) of the master unit) is a predetermined predetermined among the chillers 100 that have requested the defrost operation. The defrosting operation is permitted on a first-come-first-served basis until the number of units (simultaneous defrosting permitted number m), and the chiller 100 waiting for the defrosting operation is in a predetermined cycle with respect to the control mechanism (in this example, the chiller 100 (i) of the master unit). When there are a plurality of chillers 100 waiting for defrost operation, the chiller 100 (i) of the master unit permits the next defrost operation in descending order of the number of requests or the required time of the defrost operation. Thus, the next defrost operation can be permitted in the descending order of necessity between the chillers 100 waiting for the defrost operation. Therefore, when defrosting operation is permitted up to a predetermined number on a first-come-first-served basis, it is possible to determine the priority order of the chillers 100 that are waiting for defrosting operation.

  Further, in this embodiment, the control mechanism (in this example, the chiller 100 (i) of the master unit), the chillers 100 having the same number of defrost operation requests or the same time as the next chiller 100, in the order of increasing or decreasing identification numbers. By permitting the defrost operation, it is possible to reliably determine the priority order between the chillers 100 waiting for the defrost operation with respect to the chillers 100 having the same number of requests or the same request time of the defrost operation.

  The present invention is not limited to the embodiment described above, and can be implemented in various other forms. Therefore, such an embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

1 Chiller System 10 Compressor 11 Clutch 20 Refrigerant-Air Heat Exchanger 30 Refrigerant-Air Heat Exchanger Fan 40 Expansion Valve 41 First Expansion Valve 42 Second Expansion Valve 50 Refrigerant-Circulating Fluid Heat Exchanger 60 Engine 70 Engine Waste Heat Recovery device 81 Oil separator 81a Valve 82 Accumulator 83 Receiver 100 Chiller 110 Refrigerant circuit 111 Four-way valve 112 Bridge circuit 1121 First check valve row 1122 Second check valve row 112a First check valve 112b Second check valve 112c Second 3 check valve 112d 4th check valve 113a high pressure gas refrigerant path 113b first low pressure gas refrigerant path 113b1 merge path 113c first gas refrigerant path 113d first refrigerant path 113e high pressure liquid refrigerant path 113f first low pressure gas-liquid two-phase refrigerant Path 113g second refrigerant path 113h second gas refrigerant path 113i second low Gas-liquid two-phase refrigerant path 113j Second low-pressure gas refrigerant path 120 Cooling water circuit 121 First thermostat type switching valve 122 Second thermostat type switching valve 123 Radiator 124a Outflow path 124b Inflow path 124c First path 124d Second path 124e Third Path 124f Fourth path 124g Fifth path 130 Circulating pump 140 Controller 141 Processing unit 142 Storage unit 151 First pressure sensor 152 Second pressure sensor 161 First temperature sensor 162 Second temperature sensor 170 Rotation speed sensor 200 Circulating fluid circuit 210 Inflow trunk pipe 211 Inflow branch pipe 220 Outflow trunk pipe 221 Outflow branch pipe 231 Inflow circulation fluid temperature sensor 232 Outflow circulation fluid temperature sensor 300 Circulation pump FLa Defrost request flag FLb Defrost permission flag P1 First intermediate connection point P2 Outflow connection point P3 First 2 indirect Point P4 inflow connection point P5 merging point P6 merging point P7 confluence c permission criteria Number m simultaneous defrost Permitted Number n connected units

Claims (3)

A chiller system in which a plurality of heat pump chillers that adjust the temperature of the circulating fluid for temperature control as a heat medium by the heat of condensation or evaporation of the refrigerant are connected,
Any one of the plurality of chillers is designated as a chiller of the master unit,
Of the plurality of chillers, a chiller that requires defrost operation requests the defrost operation from the chiller of the master unit,
The chiller of the master unit permits the defrost operation on a first-come-first-served basis up to a predetermined number of chillers that have requested the defrost operation,
The chiller waiting for the defrost operation requests the defrost operation from the chiller of the master unit at a predetermined cycle,
When there are a plurality of chillers waiting for the defrost operation, the chiller of the master unit permits the next defrost operation in descending order of the number of requests or the required time of the defrost operation. . The chiller system according to claim 1,
The chiller system according to claim 1, wherein the chiller of the base unit permits the next defrosting operation in order of increasing or decreasing identification number for chillers having the same number of requests or the same time for the defrosting operation. A chiller system in which a plurality of heat pump chillers that adjust the temperature of the circulating fluid for temperature control as a heat medium by the heat of condensation or evaporation of the refrigerant are connected,
A control mechanism for controlling the operation of the plurality of chillers;
Of the plurality of chillers, a chiller that requires defrost operation requests the defrost operation from the control mechanism,
The control mechanism permits the defrost operation on a first-come-first-served basis up to a predetermined number of chillers that have requested the defrost operation,
The chiller waiting for the defrost operation requests the control mechanism for the defrost operation at a predetermined cycle,
The control mechanism, when there are a plurality of chillers waiting for the defrost operation, permits the next defrost operation in descending order of the number of requests or the required time of the defrost operation.

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