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EP-3859236-B1 - DUAL CHILLER

EP3859236B1EP 3859236 B1EP3859236 B1EP 3859236B1EP-3859236-B1

Inventors

  • SAKAGUCHI, TETSUO

Dates

Publication Date
20260513
Application Date
20190326

Claims (5)

  1. A dual chiller (1), comprising: a first coolant circuit (3) that is configured to supply a first coolant (7) to a first load (5) at a set flow rate; a second coolant circuit (4) is configured to supply a second coolant (8) to a second load (6) at a set flow rate; a refrigeration circuit (2) that is configured to adjust temperatures of the first coolant (7) and the second coolant (8) to set temperatures; and a control device (10) that controls the entire chiller (1), wherein the refrigeration circuit (2) includes a compressor (16) that compresses a gas refrigerant into a high-temperature, high-pressure gas refrigerant, a condenser (17) that cools the gas refrigerant supplied from the compressor (16) into a low-temperature, high-pressure liquid refrigerant, a first main expansion valve (18) and a second main expansion valve (19) that cause the liquid refrigerant supplied from the condenser (17) to expand into low-temperature, low-pressure liquid refrigerants and that have adjustable opening degrees, a first heat exchanger (21) that exchanges heat of the liquid refrigerant supplied from the first main expansion valve (18) with that of the first coolant (7) in the first coolant circuit (3) into a low-pressure gas refrigerant, and a second heat exchanger (22) that exchanges heat of the liquid refrigerant supplied from the second main expansion valve (19) with that of the second coolant (8) in the second coolant circuit (4) into a low-pressure gas refrigerant, and the first main expansion valve (18) and the first heat exchanger (21) are connected to each other in series and form a first heat exchange flow path portion (23), the second main expansion valve (19) and the second heat exchanger (22) are connected to each other in series and form a second heat exchange flow path portion (24), and the first heat exchange flow path portion (23) and the second heat exchange flow path portion (24) are connected to each other in parallel, wherein the refrigeration circuit (2) has a first branch flow path (25) that connects a branch point (2c) between the compressor (16) and the condenser (17) and a meeting point (2d) on the first heat exchange flow path portion (23) between the first main expansion valve (18) and the first heat exchanger (21) to each other, and a second branch flow path (26) that connects the branch point (2c) and a meeting point (2e) on the second heat exchange flow path portion (24) between the second main expansion valve (19) and the second heat exchanger (22) to each other, a first sub expansion valve (27) that has an adjustable opening degree is connected to the first branch flow path (25), and a second sub expansion valve (28) that has an adjustable opening degree is connected to the second branch flow path (26), wherein the first coolant circuit (3) includes a first tank (40) that contains the first coolant (7), a first pump (41) that supplies the first coolant (7) in the first tank (40) to the first heat exchanger (21) through a primary supply pipeline (43), a secondary supply pipeline (44) through which the first coolant (7) that has the temperature adjusted by the first heat exchanger (21) is configured to be supplied to the first load (5), a first temperature sensor (51) that is connected to the secondary supply pipeline (44), a return pipeline (45) through which the first coolant (7) from the first load (5) is configured to be returned to the first tank (40), a supply load connection port (11) that is formed in an end portion of the secondary supply pipeline (44), and a return load connection port (12) that is formed in an end portion of the return pipeline (45), wherein the second coolant circuit (4) includes a second tank (60) that contains the second coolant (8), a second pump (61) that supplies the second coolant (8) in the second tank (60) to the second heat exchanger (22) through a primary supply pipeline (63), a secondary supply pipeline (64) through which the second coolant (8) that has the temperature adjusted by the second heat exchanger (22) is is configured to be supplied to the second load (6), a second temperature sensor (71) that is connected to the secondary supply pipeline (64), a return pipeline (65) through which the second coolant (8) from the second load (6) is configured to be returned to the second tank (60), a supply load connection port (13) that is formed in an end portion of the secondary supply pipeline (64), and a return load connection port (14) that is formed in an end portion of the return pipeline (65), and wherein the control device(10) is configured such that the set temperature of the second coolant (8) is equal to the set temperature of the first coolant (7) or higher than the set temperature of the first coolant (7), the set flow rate of the first coolant (7) is higher than the set flow rate of the second coolant (8), and a volume of the first tank (40) is larger than a volume of the second tank (60).
  2. The dual chiller (1) according to Claim 1, wherein the second coolant circuit (4) includes a conductivity adjustment mechanism (80) for adjusting electrical conductivity of the second coolant (8), the conductivity adjustment mechanism (80) includes a DI filter (78) for removing an ionic substance in the second coolant (8), a conductivity sensor (79) for measuring the electrical conductivity of the second coolant (8), and a solenoid valve (77) that opens or closes depending on the electrical conductivity that is measured by the conductivity sensor (79), the DI filter (78) and the solenoid valve (77) are connected to a filtration pipeline (76) that connects the secondary supply pipeline (64) and the return pipeline (65) of the second coolant circuit (4) to each other, and the conductivity sensor (79) is connected to the return pipeline (65) of the second coolant circuit (4).
  3. The dual chiller (1) according to Claim 1 or Claim 2, wherein the refrigeration circuit (2), the first coolant circuit (3), and the second coolant circuit (4) are contained in a housing (9), and the supply load connection port (11) and the return load connection port (12) of the first coolant circuit (3) and the supply load connection port (13) and the return load connection port (14) of the second coolant circuit (4) are located outside the housing (9), and wherein the first coolant circuit (3) and the second coolant circuit (4) include a first filter (46) and a second filter (66) for removing physical impurities that are contained in the first coolant (7) and the second coolant (8), and the first filter (46) and the second filter (66) are mounted on the respective supply load connection ports (11, 13) of the first coolant circuit (3) and the second coolant circuit (4) outside the housing (9).
  4. The dual chiller (1) according to Claim 1, wherein the control device (10) adjusts flow rates of the low-temperature refrigerants and high-temperature refrigerants that flow into the first heat exchanger (21) and the second heat exchanger (22) by correlatively adjusting the opening degrees of the first main expansion valve (18) and the first sub expansion valve (27) that are connected to the first heat exchanger (21), and the opening degrees of the second main expansion valve (19) and the second sub expansion valve (28) that are connected to the second heat exchanger (22), based on the temperatures of the first coolant (7) and the second coolant (8) that are measured by the first temperature sensor (51) of the first coolant circuit (3) and the second temperature sensor (71) of the second coolant circuit (4), such that the temperatures of the first coolant (7) and the second coolant (8) in the first coolant circuit (3) and the second coolant circuit (4) are held at the set temperatures.
  5. The dual chiller (1) according to Claim 1, wherein the first pump (41) of the first coolant circuit (3) is an immersion pump that is disposed in the first tank (40), and the second pump (61) of the second coolant circuit (4) is a non-immersion pump that is disposed outside the second tank (60).

Description

Technical Field The present invention relates to a chiller that separately supplies a coolant that has an adjusted temperature to a load to keep the temperature of the load constant, and more specifically to a dual chiller that enables the temperatures of multiple loads to be kept constant. Background Art As disclosed in PTL 1, a known chiller supplies a coolant that has an adjusted temperature to multiple loads to keep the temperatures of the multiple loads constant. The known chiller includes a single refrigeration circuit and two coolant circuits through which the coolant is separately supplied to two loads. Two heat exchangers are connected to the refrigeration circuit in series. One of the heat exchangers adjusts the temperature of the coolant in one of the coolant circuits, and the other heat exchanger adjusts the temperature of the coolant in the other coolant circuit. This will be more specifically described. The known chiller adjusts the temperature of a coolant that is contained in a tank by using the heat exchangers of the refrigeration circuit and an electric heater to a set temperature and supplies the coolant that has the adjusted temperature in the tank to the loads through a supply flow path that does not extend through the heat exchangers. For this reason, in the case where the chiller measures the temperature of the coolant in the tank, and the temperature is higher than the set temperature, the coolant is supplied to the heat exchangers of the from the supply flow path and returns to the tank after being cooled by the heat exchangers. In the case where the temperature of the coolant in the tank is lower than the set temperature, the coolant is heated by using the electric heater that is disposed in the tank. The known chiller does not supply the coolant to the loads right after the temperature is adjusted by the heat exchangers and the heater but thus puts the coolant once in the tank after the temperature is adjusted and supplies the coolant to the loads from the tank. Accordingly, a difficulty lies in responsiveness to changes in the temperature of the coolant, and there is a problem in that a load variation when viewed from the refrigeration circuit is large. Since the two heat exchangers of the refrigeration circuit are connected in series, and the flow rates of refrigerants that flow through the two heat exchangers are controlled by a single expansion valve, it is difficult to separately control the flow rates and temperatures of the refrigerants that flow through the two heat exchangers so as to match the temperatures of the coolants in the respective coolant circuits connected thereto. JP 2017 116118 A discloses a chiller device with two separate refrigeration cycles, wherein each refrigeration cycle comprises a refrigerant tank with a heater, a pump, a work, and an evaporator. In each cycle the pump circulates the refrigerant from the tank through the interposed work and to a first side of the evaporator. In each refrigeration cycle, the pump circulates the refrigerant from the tank through the interposed work and to a first side of the evaporator. The heaters in the tanks are configured to increase the temperature in the tanks, whereby the temperature is monitored by temperature sensors and stabilized by a PID control. The respective second sides of the evaporators form a third refrigeration cycle that is coupled to a cooling circuit. Citation List Patent Literature PTL 1: Japanese Examined Utility Model Registration Application Publication No. 5-17635 Summary of Invention Technical Problem It is a technical problem of the present invention to provide a chiller that is capable of separately controlling the flow rates and temperatures of refrigerants that flow through multiple heat exchangers so as to match the temperatures of coolants in coolant circuits that are connected to the respective heat exchangers to increase responsiveness to changes in the temperatures of the coolants and the precision of temperature control. Solution to Problem To solve the problem, a dual chiller according to the present invention is provided as defined in claim 1. It includes a first coolant circuit that supplies a first coolant to a first load at a set flow rate, a second coolant circuit that supplies a second coolant to a second load at a set flow rate, a refrigeration circuit that adjusts temperatures of the first coolant and the second coolant to set temperatures, and a control device that controls the entire chiller. The refrigeration circuit includes a compressor that compresses a gas refrigerant into a high-temperature, high-pressure gas refrigerant, a condenser that cools the gas refrigerant supplied from the compressor into a low-temperature, high-pressure liquid refrigerant, a first main expansion valve and a second main expansion valve that cause the liquid refrigerant supplied from the condenser to expand into low-temperature, low-pressure liquid refrigerants and that have adjustable ope