Temperature control method

Abstract

To provide a temperature control method that reduces costs by performing accurate temperature control, and eliminates waste of refrigerant flow rate for adjusting the temperature of a secondary-side fluid.SOLUTION: A temperature of a secondary-side fluid and a pressure of a low-pressure circuit are set in advance by using a temperature control system equipped with: a chiller 2 equipped with a heat exchanger 7, a compressor 4, a condenser 5, a cooling expansion valve 6 and a heating expansion valve 9; a secondary-side circulation circuit 12 for supplying the secondary-side fluid which has been controlled at a prescribed temperature to a temperature control target; a temperature sensor 13 for measuring a temperature of the secondary-side fluid; and a pressure sensor for measuring the pressure of the low-pressure circuit of the chiller. When cooling the secondary-side fluid, the cooling expansion valve is operated. When heating the fluid, the heating expansion valve is operated, and outputs of both the cooling expansion valve and the heating expansion valve are made to cross each other near a lower limit value, so that a refrigerant circulation quantity does not fall below a minimum circulation quantity. When the secondary-side fluid temperature is different from a set temperature, temperature control by an operation of the expansion valve and pressure control by an operation of the compressor are performed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature control method used to control the temperature of various processes in the manufacture of semiconductors and the like, and more particularly to a temperature control method for controlling the temperature of various processes by supplying and circulating a secondary fluid such as a liquid or gas to the various processes to be temperature-adjusted, which makes it possible to reduce costs by performing high-precision temperature control and eliminate waste of the flow rate of refrigerant for adjusting the temperature of the secondary fluid. [Background technology]

[0002] As is well known, in the manufacture of semiconductors, flat panel displays ("FPDs") and the like, temperature control is required in various processes to achieve stable yields of film formation, stable yields of etching, and the like.

[0003] Conventionally, the temperature control of each process is performed by a temperature control system using a temperature control device called a chiller. That is, a secondary fluid such as cold water is circulated between the chiller and each process to be temperature controlled, and the temperature of the secondary fluid supplied to each process is controlled to a set temperature by the chiller, thereby controlling the temperature of each process in semiconductor manufacturing.

[0004] Here, the configuration of a typical temperature adjustment system will be described with reference to FIG. 3. FIG. 3 is a diagram showing the circuit configuration of a conventionally used temperature adjustment system, in which 51 is the temperature adjustment system.

[0005] Generally, a temperature control system 51 for controlling the temperature of various processes in semiconductor manufacturing supplies secondary fluids such as cold water, air, etc. to the various processes whose temperatures are to be controlled, and has a secondary circulation circuit 53 for circulating the supplied secondary fluid, and a chiller 52 for controlling the temperature of the secondary fluid supplied to the various processes whose temperatures are to be controlled by this secondary circulation circuit 53 to a predetermined temperature.

[0006] In the figure, the chiller is indicated by a dotted line 52, and as is well known, this chiller 52 is equipped with a primary side circulation circuit 61 for circulating a refrigerant. A compressor 55, a condenser 56, an expansion valve 57, and a heat exchanger 58 are arranged along the primary side circulation circuit 61, and the secondary side circulation circuit 53 is connected to the heat exchanger 58.

[0007] The primary side circulation circuit 61 circulates the refrigerant between the compressor 55, the condenser 56, the expansion valve 57, and the heat exchanger 58, while the heat exchanger 58 exchanges heat between the secondary side fluid that has returned via the secondary side circulation circuit 53 and the refrigerant that has circulated through the primary side circulation circuit 61, thereby controlling the temperature of the secondary side fluid to be supplied to various processes that are to be temperature-controlled to a predetermined temperature.

[0008] That is, in the chiller 52, the compressor 55 compresses the low-pressure refrigerant vaporized in the heat exchanger 58 to a high pressure, the refrigerant pressurized by the compressor 55 is condensed into a liquid by heat exchange in the condenser 56, the refrigerant that has been made into a high-pressure liquid by the condenser 56 is made low-pressure in the expansion valve 57, and then in the heat exchanger 58, it exchanges heat with the secondary-side fluid that has returned to the heat exchanger 58 via the secondary-side circulation circuit 53 to control the temperature of the secondary-side fluid to a predetermined temperature, and then this refrigeration cycle is repeated. Therefore, in the primary-side circulation circuit 61, the circuit from the heat exchanger 58 to the compressor 55 is a low-pressure circuit.

[0009] In addition, in chiller 51, heater 63 is disposed on the supply side of secondary circulation circuit 53, and the temperature of the secondary fluid cooled in heat exchanger 58 is raised to a set temperature. That is, in conventional chillers, since it is not possible to perform precise temperature control, the secondary fluid is cooled to a temperature lower than the set temperature, and then heated by heater 63 to bring the temperature of the secondary fluid to the set temperature.

[0010] In the figure, 67 denotes a driving means for circulating the secondary fluid within the secondary circulation circuit 53, which is a pump when cold water is used as the secondary fluid, and a fan when air is used as the secondary fluid.

[0011] In the figure, reference numeral 54 denotes a cooling water circulation circuit for supplying cooling water to lower the temperature of the refrigerant in the condenser 56 to condense it, 59 denotes an accumulator, and 65 denotes a control means such as a microcomputer for controlling the operation of the entire device.

[0012] Furthermore, in the figure, reference numeral 62 denotes a heating circuit for mixing the refrigerant coming out of the expansion valve 57 with high-temperature refrigerant ("hot gas") pressurized by the compressor 55, and a thermal expansion valve 60 is disposed in the path of this heating circuit 62. That is, in a conventional chiller 52, in order to prevent the temperature of the secondary side fluid in the heat exchanger 58 from being cooled more than necessary, the heating circuit 62 and the thermal expansion valve 60 are provided, and the thermal expansion valve 60 is opened to mix the refrigerant coming out of the expansion valve 57 with the hot gas, which is a high-temperature refrigerant coming out of the compressor 55, thereby raising the temperature of the refrigerant supplied to the heat exchanger 58, thereby preventing the secondary side fluid from becoming more cold than necessary and reducing the burden on the heater 63.

[0013] However, in the conventional chiller 51, temperature sensors 64 were placed before and after the heater 63, and these temperature sensors 64 measured the temperature of the secondary fluid in the secondary circulation circuit 53, and the opening and closing of the thermal expansion valve 60 was controlled solely on the basis of whether the temperature was higher or lower than a predetermined temperature, so although the load on the heater 63 could be somewhat reduced by opening the thermal expansion valve 60 to raise the temperature of the refrigerant supplied to the heat exchanger 58, the temperature of the secondary fluid could not be precisely controlled. For this reason, heating by the heater 63 was necessary, and therefore it was difficult to reduce the cost of the entire device.

[0014] Furthermore, the supply of hot gas in conventional chillers ignored the overall amount of refrigerant circulating within the refrigeration cycle and controlled the heating and expansion valve alone, which resulted in an unbalanced workload for the compressor and instability, and in the worst case scenario, could cause the compressor to stop due to abnormal high pressure.

[0015] Therefore, the applicant has previously proposed a method of arranging a temperature sensor to measure the temperature of the secondary fluid supplied to various processes to be temperature-controlled, and adjusting the opening of the cooling expansion valve and the heating expansion valve according to the measurement results of this temperature sensor, thereby controlling the temperature of the secondary fluid supplied to the temperature-controlled object to a set temperature. This allows for fine temperature control, unlike conventional chillers that only controlled the opening and closing of the heating expansion valve based on whether the temperature of the secondary fluid was higher or lower than a predetermined temperature, and eliminates the need to cool the secondary fluid to a set temperature or lower and then heat it with a heater to bring it to the set temperature. This makes it possible to eliminate the need for a heater, making it possible to achieve energy savings and low costs.

[0016] In addition, when adjusting the opening of the cooling expansion valve and the heating expansion valve simultaneously, the openings are adjusted inversely proportional to each other to keep the amount of refrigerant circulating through the primary circulation circuit constant, thereby maintaining a balance in the workload of the compressors and preventing the compressors from becoming unstable. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Patent No. 6320897 [Patent Document 2] JP 2002-023862 A [Patent Document 3] Japanese Patent Application Publication No. 07-151441 Summary of the Invention [Problem to be solved by the invention]

[0018] In the above-mentioned method, when cooling the secondary fluid, the cooling expansion valve is opened and the heating expansion valve is closed until the temperature of the secondary fluid reaches the set temperature, and when heating the secondary fluid, the cooling expansion valve is closed and the heating expansion valve is opened until the temperature of the secondary fluid reaches the set temperature. This makes it possible to eliminate the need for a heater and achieve energy savings and low costs. Furthermore, when the opening of the cooling expansion valve and the heating expansion valve are adjusted simultaneously, the openings are operated inversely proportional to each other. This makes it possible to maintain a constant amount of refrigerant circulating through the primary circulation circuit, thereby maintaining a balance in the workload of the compressor and preventing the compressor from becoming unstable. However, it has been pointed out that this method causes a problem of refrigerant mixing loss.

[0019] When the cooling expansion valve and the heating expansion valve are operated simultaneously to perform cooling control and heating control at the same time, it is necessary to perform temperature control by canceling out the ratio of their respective capacities, but because the cancellation generates mixing loss, it is necessary to operate with an excess of energy consumption over the required cooling capacity or heating capacity. For example, in the case of cooling operation, in order to maintain a constant refrigerant circulation volume, it is necessary to add a refrigerant circulation volume that is insufficient to the refrigerant circulation volume of the required cooling capacity. Then, it is necessary to increase the opening of the cooling expansion valve and the heating expansion valve so that this added "insufficient refrigerant circulation volume" is canceled out by the cooling capacity and the heating capacity, and becomes zero, which enables high-precision temperature control. However, on the other hand, the insufficient refrigerant circulation volume is completely unnecessary, and this refrigerant circulation volume that must be added causes refrigerant mixing loss.

[0020] Therefore, an object of the present invention is to provide a temperature control method which enables costs to be reduced by performing highly accurate temperature control and which also enables the elimination of waste of refrigerant flow rate for adjusting the temperature of the secondary fluid. [Means for solving the problem]

[0021] The temperature control method of the present invention includes the steps of: a secondary circulation circuit for repeating a cycle in which the secondary fluid is circulated, the secondary fluid controlled to a predetermined temperature is supplied to a temperature control target, and the secondary fluid circulated from the temperature control target is controlled to a predetermined temperature and then supplied to the temperature control target; a primary side circulation circuit for circulating a refrigerant; a heat exchanger arranged midway through the primary side circulation circuit, to which the secondary side circulation circuit is connected, for controlling the temperature of the secondary side fluid supplied to a temperature adjustment target at a predetermined temperature by heat exchanging between the refrigerant supplied via the primary side circulation circuit and the secondary side fluid; a compressor for compressing a vaporized refrigerant to a high pressure, a condenser for condensing the refrigerant pressurized by the compressor by heat exchange, a cooling expansion valve for reducing the pressure of the refrigerant liquefied by the condenser and supplying it to the heat exchanger; a heating circuit connecting between the compressor and the condenser and between the cooling expansion valve and the heat exchanger in the primary side circulation circuit, for supplying the high-temperature refrigerant pressurized by the compressor to the heat exchanger; and a heating expansion valve arranged midway through the heating circuit; A temperature sensor for measuring the temperature of a secondary fluid supplied to a temperature control target; a pressure sensor for measuring a refrigerant pressure between the heat exchanger and the compressor in the primary circulation circuit; A temperature control method for controlling a temperature of a secondary fluid supplied to a temperature control target to a predetermined temperature in order to control temperatures of various processes as a temperature control target to a predetermined temperature using a temperature control system including the following: The temperature of the secondary fluid to be supplied to the temperature control target and the refrigerant pressure between the heat exchanger and the compressor are set in advance, When cooling the secondary fluid, the refrigerant is circulated through the heat exchanger, compressor, condenser and cooling expansion valve to control the supply temperature of the secondary fluid to various processes, and when heating the secondary fluid, the refrigerant is circulated through the heat exchanger, compressor and heating expansion valve to control the supply temperature of the secondary fluid to various processes, and the output of the cooling expansion valve and the output of the heating expansion valve cross each other near their lower limits to prevent both the opening of the cooling expansion valve and the opening of the heating expansion valve from being fully closed, and to prevent the circulation volume of the refrigerant circulating through the primary circulation circuit from falling below a minimum circulation volume. When the temperature of the secondary fluid supplied to the temperature control target differs from the set temperature, By changing the opening degree of either the cooling expansion valve or the heating expansion valve, the temperature of the secondary fluid to be supplied to the temperature adjustment target is returned to the preset temperature; When the opening degree of the cooling expansion valve or the heating expansion valve is changed so that the refrigerant pressure between the heat exchanger and the compressor in the primary circulation circuit differs from the preset pressure, the compressor speed is adjusted to adjust the amount of refrigerant discharged from the compressor, thereby restoring the refrigerant pressure between the heat exchanger and the compressor to the preset pressure; When the temperature of the secondary fluid supplied to the temperature control target changes by adjusting the compressor rotation speed and thereby adjusting the amount of refrigerant discharged from the compressor, the temperature of the secondary fluid supplied to the temperature control target is returned to the set temperature by slightly changing the opening of either the cooling expansion valve or the heating expansion valve. Effect of the Invention

[0022] In the temperature control method of the present invention, in a temperature control system having a heat exchanger, a compressor, a condenser, and a cooling expansion valve, and using a chiller equipped with a heating circulation circuit and a heating expansion valve that supplies a high-temperature refrigerant pressurized by the compressor to the heat exchanger, to control the temperature of a secondary fluid supplied to a temperature control target, when cooling the secondary fluid, the supply temperature of the secondary fluid to various processes is controlled by circulating the refrigerant while passing through the heat exchanger, the compressor, the condenser, and the cooling expansion valve, and when heating the secondary fluid, the supply temperature of the secondary fluid to various processes is controlled by circulating the refrigerant while passing through the heat exchanger, the compressor, and the heating expansion valve. Therefore, unlike the conventional method in which the openings of the cooling expansion valve and the heating expansion valve are adjusted simultaneously and the openings are operated inversely proportional to each other at that time, no mixing loss of the refrigerant occurs.

[0023] In addition, in the temperature control method of the present invention, as described above, the cooling expansion valve is operated when the secondary fluid is cooled, and the heating expansion valve is operated when the secondary fluid is heated, and in this case, the output of the cooling expansion valve and the output of the heating expansion valve are crossed near the lower limit value to prevent both the opening of the cooling expansion valve and the opening of the heating expansion valve from being fully closed, so that the circulation amount of the refrigerant circulating in the primary circulation circuit does not fall below the minimum circulation amount. Therefore, by narrowing the opening of the cooling expansion valve or the heating expansion valve, the circulation amount of the refrigerant decreases, and it is possible to prevent the circulating refrigerant from falling below the minimum circulation amount, which causes the low pressure switch to operate to protect the compressor and cause the device to stop in an emergency.

[0024] Furthermore, in the present invention, a variable speed compressor is used as the compressor, and a temperature sensor is provided for measuring the temperature of the secondary fluid that has been heat exchanged with the refrigerant in the heat exchanger, and a pressure sensor is provided for measuring the refrigerant pressure between the heat exchanger and the compressor in the primary side circulation circuit. When the temperature of the secondary fluid supplied to the temperature control target differs from a set temperature, the opening of either the cooling expansion valve or the heating expansion valve is changed to return the temperature of the secondary fluid supplied to the temperature control target to a preset temperature, and then the opening of the cooling expansion valve or the heating expansion valve is changed to return the temperature of the secondary fluid supplied to the temperature control target to a preset temperature. When the refrigerant pressure between the heat exchanger and the compressor differs from a preset pressure, the compressor speed is adjusted to adjust the amount of refrigerant discharged from the compressor to return the refrigerant pressure between the heat exchanger and the compressor to the preset pressure, and then, when the temperature of the secondary fluid supplied to the temperature control target changes by adjusting the compressor speed to adjust the amount of refrigerant discharged from the compressor, the opening of either the cooling expansion valve or the heating expansion valve is slightly changed to return the temperature of the secondary fluid supplied to the temperature control target to the set temperature. Therefore, unlike when a constant-speed compressor is used as in the past, the compressor speed can be changed according to the amount of refrigerant circulating, which prevents the COP from deteriorating, and high-precision control can be performed by combining temperature control by the opening of the expansion valve based on temperature and pressure control by changing the compressor speed based on pressure. [Brief description of the drawings]

[0025] [Figure 1] 1 is a block diagram for explaining a temperature adjustment system used in an embodiment of a temperature control method of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a control system of a temperature adjustment system used in an embodiment of a temperature control method of the present invention. [Diagram 3] FIG. 1 is a block diagram for explaining a configuration of a conventional temperature adjustment system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The temperature control method of the present invention is a temperature control method for controlling the temperature of a secondary fluid supplied to a temperature control target to a predetermined temperature in order to control the temperatures of various processes in the manufacture of a semiconductor or the like as a temperature control target to a predetermined temperature, and temperature control is performed by a temperature control system equipped with a secondary side circulation circuit for circulating the secondary side fluid and supplying the secondary side fluid controlled to the predetermined temperature to the temperature control target, while controlling the secondary side fluid circulated from the temperature control target to the predetermined temperature and then supplying it to the temperature control target, and a chiller for controlling the secondary side fluid circulated from the temperature control target by the secondary side circulation circuit to the predetermined temperature.

[0027] Like a general chiller, the chiller has a primary side circulation circuit that circulates refrigerant, and the secondary side circulation circuit is connected midway through this primary side circulation circuit to a heat exchanger that controls the temperature of the secondary side fluid supplied to the temperature control target at a predetermined temperature by exchanging heat between the refrigerant supplied via the primary side circulation circuit and the secondary side fluid, a variable speed compressor for compressing and high-pressureing the refrigerant output from the heat exchanger, a heating circuit that connects between the compressor and the condenser and between the cooling expansion valve and the heat exchanger in the primary side circulation circuit and supplies the high-temperature refrigerant pressurized by the compressor to the heat exchanger, and a heating expansion valve located midway through this heating circuit, thereby controlling the secondary side fluid circulated from the temperature control target to a predetermined temperature.

[0028] In addition, a temperature control system that implements the temperature control method of the present invention is equipped with a temperature sensor that measures the temperature of the secondary fluid supplied to the object to be temperature controlled, and a pressure sensor that measures the refrigerant pressure between the heat exchanger and the compressor in the primary circulation circuit.

[0029] The temperature of the secondary side fluid supplied to the temperature control target and the refrigerant pressure between the heat exchanger and the compressor are set in advance, and when cooling the secondary side fluid, the refrigerant is circulated through the heat exchanger, compressor, condenser, and cooling expansion valve to control the supply temperature of the secondary side fluid to various processes to the preset temperature, and when heating the secondary side fluid, the refrigerant is circulated through the heat exchanger, compressor, and heating expansion valve to control the supply temperature of the secondary side fluid to various processes to the preset temperature, thereby preventing refrigerant mixing loss.

[0030] In addition, when operating the cooling expansion valve and the heating expansion valve, the output of the cooling expansion valve and the output of the heating expansion valve cross each other near their lower limit values, preventing both the opening of the cooling expansion valve and the opening of the heating expansion valve from being fully closed and preventing the circulation volume of the refrigerant circulating through the primary side circulation circuit from falling below the minimum circulation volume. This prevents the circulating refrigerant from falling below the minimum circulation volume, which would cause the low pressure switch to activate to protect the compressor and cause the device to shut down in an emergency.

[0031] Then, if the temperature of the secondary fluid supplied to the temperature control target differs from the set temperature, the opening degree of either the cooling expansion valve or the heating expansion valve is changed to return the temperature of the secondary fluid supplied to the temperature control target to the previously set temperature.

[0032] Next, the opening of the cooling expansion valve or the heating expansion valve is changed to return the temperature of the secondary fluid supplied to the temperature control target to a preset temperature. If the refrigerant pressure between the heat exchanger and the compressor in the primary side circulation circuit differs from the preset pressure, the compressor rotation speed is adjusted to adjust the refrigerant discharge amount from the compressor, thereby returning the refrigerant pressure between the heat exchanger and the compressor to the preset pressure.

[0033] Next, when the temperature of the secondary fluid supplied to the temperature control target changes by adjusting the compressor rotation speed to adjust the amount of refrigerant discharged from the compressor and returning the refrigerant pressure between the heat exchanger and the compressor to a preset pressure, the opening of either the cooling expansion valve or the heating expansion valve is further slightly changed to return the temperature of the secondary fluid supplied to the temperature control target to the preset temperature, thereby adjusting the temperature of the secondary fluid supplied to the temperature control target to the preset temperature, and adjusting the refrigerant pressure between the heat exchanger and the compressor to the preset pressure.

[0034] Here, it is preferable to provide a control means such as a microcomputer for controlling the overall operation of the temperature control system, and to automatically control the operation of at least the compressor, cooling expansion valve, and heating expansion valve based on the measurement results of the temperature sensor and pressure sensor. EXAMPLES

[0035] An embodiment of the temperature control method of the present invention will be described. The temperature control method of the present embodiment is a method for controlling the temperature of a secondary fluid, which is supplied to a temperature control target to control the temperature of the temperature control target by controlling the temperature of the temperature control target, to a set temperature, in various processes in the manufacture of semiconductors, flat panel displays ("FPD"), etc., as a temperature control target. The temperature control of the secondary fluid is performed by a temperature control system having a secondary circulation circuit for repeating a cycle in which the secondary fluid is circulated, the secondary fluid controlled to a predetermined temperature is supplied to the temperature control target, and the secondary fluid circulated from the temperature control target is controlled to a predetermined temperature and then supplied to the temperature control target, and a chiller for controlling the secondary fluid circulated from the temperature control target to a predetermined temperature. In this embodiment, the secondary fluid is not limited to a liquid such as cold water, and may be a gas such as air.

[0036] 1 is a block diagram showing the configuration of a temperature control system for implementing the temperature control method of this embodiment, in which 1 is the temperature control system, 2 is a chiller, and 12 is a secondary circulation circuit.

[0037] First, the chiller 2 will be described. The chiller 2 shown by the dotted line in the figure is the chiller, and the chiller 2 used in the temperature control method of this embodiment has a primary side circulation circuit 3 that circulates a refrigerant, similar to commonly used chillers. A heat exchanger, a compressor, a condenser, and a cooling expansion valve are arranged along the primary side circulation circuit 3. The chiller 2 also has a heating circuit 8 that connects between the compressor 4 and the condenser 5 and between the cooling expansion valve 6 and the heat exchanger 7 in the primary side circulation circuit 3, and a heating expansion valve 9 is arranged along the heating circuit 8.

[0038] In the figure, 7 is a heat exchanger, to which a secondary side circulation circuit 12 is connected, and performs heat exchange between the refrigerant supplied via the primary side circulation circuit 3 and the secondary side fluid returning from the temperature control target through the secondary side circulation circuit 12, thereby controlling the temperature of the secondary side fluid supplied to the temperature control target to a predetermined temperature.

[0039] Next, in the figure, 4 is a compressor, and this compressor 4 has a function of compressing the refrigerant supplied from the heat exchanger 7 to make it high pressure and high temperature. For this reason, the section from the heat exchanger 7 to the compressor 4 in the primary side circulation circuit 3 is a low pressure circuit for the refrigerant. In this embodiment, the compressor 4 is a variable speed compressor controlled by an inverter.

[0040] In the figure, reference numeral 10 denotes an accumulator, which is used to prevent refrigerant that has not been completely vaporized in the heat exchanger 7 from being drawn into the compressor 4 in the liquid state.

[0041] Also in the figure, reference numeral 14 denotes a pressure sensor. That is, in the chiller 2 of this embodiment, pressure sensors 14 are arranged in the primary side circulation circuit 3 between the heat exchanger 7 and the accumulator 10 and between the accumulator 10 and the compressor 4 to monitor the pressure of the refrigerant in the low-pressure circuit. However, this is not limited to pressure sensors only, and in addition to the pressure sensors, a temperature sensor capable of measuring the temperature of the refrigerant in the low-pressure circuit may be installed.

[0042] Next, in the figure, reference numeral 5 denotes a condenser, which is used in the cooling operation to condense and liquefy the refrigerant pressurized by the compressor 4 through heat exchange.

[0043] In the figure, reference numeral 11 denotes a cooling water circulation circuit used to condense the gaseous refrigerant, which has been made high pressure and high temperature by the compressor 4, by heat exchange in the condenser 5, and this cooling water circulation circuit 11 is connected to a cooling water production device such as a cooling tower (not shown), and supplies the cooling water cooled in the cooling tower or the like to the condenser 5, and also serves as a circulation path for circulating the cooling water, after the cooling water has been heated by heat exchange with the refrigerant in the condenser 5, to the cooling tower or the like. Note that, in the above description, a water-cooling system in which the medium exchanging heat with the refrigerant in the condenser 5 is cooling water, has been described, but the present invention is not necessarily limited to a water-cooling system in which the refrigerant is condensed by cooling water, and a method of condensing the refrigerant by an air-cooling system may be adopted.

[0044] Next, in the figure, reference numeral 6 denotes a cooling expansion valve, which is used to reduce the pressure of the refrigerant liquefied in the condenser 5 and supply it to the heat exchanger 7 during cooling operation.

[0045] In the figure, reference numeral 8 denotes a heating circuit, and 9 denotes a thermal expansion valve. That is, in this embodiment, one end of the heating circuit 8 is connected to the primary side circulation circuit 3 between the compressor 4 and the condenser 5, and the other end of the heating circuit 8 is connected to the primary side circulation circuit 3 between the cooling expansion valve 6 and the heat exchanger 7. A thermal expansion valve 9 is disposed in the heating circuit 8, which makes it possible to supply high-temperature refrigerant pressurized by the compressor 4 to the heat exchanger 7.

[0046] Next, in the figure, 12 denotes a secondary circulation circuit. In this embodiment, the secondary circulation circuit 12 has a supply path 1201 for supplying a secondary fluid to the temperature control target, and a return path 1202 for circulating the secondary fluid returned from the temperature control target to the heat exchanger 7, and is connected to the heat exchanger 7 on the opposite side to the temperature control target. The secondary fluid is circulated between the heat exchanger 7 and various processes in the semiconductor manufacturing process that are the temperature control target, and the secondary fluid that has been controlled to a set temperature by heat exchange with the refrigerant in the heat exchanger 7 is supplied to the temperature control target, and the temperature of the secondary fluid that has been circulated and has become different from the set temperature due to the load in the various processes of the temperature control target is controlled to the set temperature in the heat exchanger 7 again and then supplied to the temperature control target.

[0047] In the figure, reference numeral 13 denotes a temperature sensor for measuring the temperature of the secondary fluid supplied to the temperature control target, and in this embodiment, the temperature of the secondary fluid supplied to the temperature control target is constantly monitored by this temperature sensor 13. Also in the figure, reference numeral 16 denotes a pump for circulating the secondary fluid in the secondary circulation circuit.

[0048] Next, in the figure, reference numeral 15 denotes a control means such as a microcomputer for controlling the overall operation of the temperature adjustment system 1. As shown in FIG. 2, this control means 15 is connected to at least the cooling expansion valve 6, the heating expansion valve 9, the compressor 4, the temperature sensor 13, the pressure sensor 14, the pump 16, a power source, etc., and controls the operation of the compressor 4, the cooling expansion valve 6, the heating expansion valve 9, the pump 16, etc.

[0049] The control means 15 supplies the required amount of refrigerant to the heat exchanger 7 by controlling the opening of the cooling expansion valve 6 and the heating expansion valve 9 in accordance with the measurement signal from the temperature sensor 13, and further controls the rotation speed of the compressor 4 in accordance with the measurement signal from the pressure sensor 14.

[0050] In this embodiment, both the cooling expansion valve 6 and the heating expansion valve 9 are electronic expansion valves, and are operated by driving a stepping motor in response to a pulse signal from a pulse converter (not shown); however, since electronic expansion valves are well known, detailed description thereof will be omitted.

[0051] The temperature control method of this embodiment using the temperature control system 1 configured as described above will be explained. In the temperature control method of this embodiment, the temperature of the secondary fluid to be supplied to the temperature control target and the pressure (low pressure) of the low pressure circuit of the refrigerant between the heat exchanger 7 and the compressor 4 are set in advance.

[0052] Then, the compressor 4 is driven to circulate the refrigerant in the primary side circulation circuit 3, and the pump 16 is driven to circulate the secondary side fluid in the secondary side circulation circuit 12. At the same time, the temperature of the secondary side fluid supplied to the temperature adjustment target is monitored by the temperature sensor 13, and the pressure of the refrigerant in the low pressure circuit is monitored by the pressure sensor 14. If the temperature of the secondary side fluid supplied to the temperature adjustment target or the pressure of the refrigerant in the low pressure circuit between the heat exchanger 7 and the compressor 4 differs from a preset temperature or pressure, the opening of the expansion valves 6, 9 and the rotation speed of the compressor 4 are changed.

[0053] First, when cooling the secondary fluid, the refrigerant is circulated within the primary side circulation circuit 3 while passing through the heat exchanger 7, the compressor 4, the condenser 5, and the cooling expansion valve 6, thereby lowering the temperature of the secondary fluid in the heat exchanger 7 to a predetermined temperature.

[0054] That is, in the compressor 4, the refrigerant vaporized in the heat exchanger 7 is compressed to a high pressure and temperature, and this high pressure, high temperature refrigerant is condensed and liquefied in the condenser 5. The liquefied refrigerant is then reduced in pressure by the cooling expansion valve 6 and supplied to the heat exchanger 7.

[0055] Then, in the heat exchanger 7, the refrigerant supplied from the cooling expansion valve 6 is vaporized and cooled by the heat of vaporization. This cooled refrigerant is then heat exchanged with the secondary side fluid that has returned from the temperature control target through the secondary side circulation circuit 12, thereby cooling the secondary side fluid and controlling it to the set temperature.

[0056] On the other hand, when the secondary fluid is heated, the refrigerant is circulated within the primary side circulation circuit 3 while passing through the heat exchanger 7, the compressor 4, and the thermal expansion valve 9, thereby raising the temperature of the secondary fluid in the heat exchanger 7 to a predetermined temperature.

[0057] That is, in the compressor 4, the refrigerant that has exchanged heat with the secondary fluid in the heat exchanger 7 is compressed to a high pressure and temperature, and this high pressure and high temperature refrigerant is supplied to the thermal expansion valve via the heating circuit 8. The refrigerant supplied to the thermal expansion valve is then reduced in pressure by the thermal expansion valve and supplied to the heat exchanger 7.

[0058] Then, in the heat exchanger 7, heat is exchanged between the supplied refrigerant and the secondary fluid, thereby heating the secondary fluid and controlling it to a set temperature.

[0059] In this way, in the temperature control method of this embodiment, the cooling expansion valve 6 is operated during cooling operation and the heating expansion valve 9 is operated during heating operation, so that refrigerant mixing loss can be prevented, unlike when the opening degrees of the cooling expansion valve 6 and the heating expansion valve 9 are adjusted simultaneously.

[0060] Next, in the temperature control method of the present invention, the output of the cooling expansion valve 6 and the output of the heating expansion valve 9 are made to cross each other near the lower limit value, thereby preventing both the opening of the cooling expansion valve 6 and the opening of the heating expansion valve 9 from being fully closed, and preventing the circulation amount of the refrigerant from falling below the minimum circulation amount. That is, during cooling operation, the opening of the cooling expansion valve 6 is narrowed so that the heating expansion valve 9 opens slightly to output when the output becomes near zero, while during heating operation, the opening of the heating expansion valve 9 is narrowed so that the cooling expansion valve 6 opens slightly to output when the output becomes near zero. This prevents the circulation amount of the refrigerant circulating through the primary side circulation circuit 3 from falling below the minimum circulation amount, and prevents the low pressure switch from activating to protect the compressor and causing the device to stop suddenly.

[0061] For example, in the case of adopting a method of operating the cooling expansion valve during cooling operation and operating the heating expansion valve during heating operation, as in the temperature control method of this embodiment, if the load in each process to be temperature-controlled during cooling operation is reduced and the temperature of the secondary fluid returning to the heat exchanger 7 drops below the temperature before the load is reduced, if no action is taken, the temperature of the secondary fluid supplied to the temperature-controlled object will be lower than the set temperature, so it is necessary to reduce the cooling capacity by narrowing the opening of the cooling expansion valve 6 and return the temperature of the secondary fluid supplied to the temperature-controlled object to the set temperature. Then, the amount of refrigerant circulating decreases, and if no action is taken and the circulating refrigerant falls below the minimum amount of circulation, the low pressure switch will be activated to protect the compressor and the device will be stopped in an emergency.

[0062] Conversely, during heating operation, if the load in each process to be temperature-controlled is reduced and the temperature of the secondary fluid returning to the heat exchanger 7 becomes higher than before the load was reduced, if no action is taken, the temperature of the secondary fluid supplied to the temperature-controlled target will be higher than the set temperature, and it is necessary to reduce the heating capacity by narrowing the opening of the thermal expansion valve 9. This will decrease the amount of refrigerant circulating, and if no action is taken and the circulating refrigerant falls below the minimum amount, the low-pressure switch will be activated to protect the compressor, causing the device to come to an emergency stop.

[0063] Therefore, in the temperature control method of this embodiment, a method is adopted in which the cooling expansion valve is operated during cooling operation and the heating expansion valve is operated during heating operation, and the output of the cooling expansion valve and the output of the heating expansion valve are crossed near the lower limit to prevent both the opening of the cooling expansion valve and the opening of the heating expansion valve from being fully closed, and the opening of the cooling expansion valve 6 is narrowed to allow the heating expansion valve to open slightly to output when the output becomes near zero during cooling operation, while the opening of the heating expansion valve 9 is narrowed to allow the cooling expansion valve 6 to open slightly to output when the output becomes near zero during heating operation, thereby preventing the circulation amount of the refrigerant circulating through the primary side circulation circuit 3 from falling below the minimum circulation amount, and preventing the low pressure switch from operating to protect the compressor and causing the device to stop in an emergency. Therefore, in order to prevent the circulation amount of the refrigerant from falling below the minimum circulation amount even when the output of one expansion valve becomes zero, the output of the cooling expansion valve and the output of the heating expansion valve are crossed near the lower limit. Therefore, in this embodiment, it is possible to simply simultaneously control the temperature control to stabilize and ensure the minimum amount of refrigerant circulation. At this time, it is better to make the cooling expansion valve output and the heating expansion valve output not linear, but to make them slowly fully close in a curved manner as they approach the lower limit. In this way, the opening degree of the closing expansion valve can be changed so that the change in heat quantity is gradual, based on the opening of the expansion valve, and the temperature control accuracy can be improved.

[0064] Next, in the temperature control method of this embodiment, when cooling or heating operation is being performed, if the load in the various processes to be temperature controlled decreases or increases, causing the temperature of the secondary fluid returning to the heat exchanger 7 to differ from the set temperature, the opening of either the cooling expansion valve 6 or the heating expansion valve 9 is changed to change the flow rate of the refrigerant supplied to the heat exchanger 7, thereby changing the cooling capacity or heating capacity of the heat exchanger 7, and returning the temperature of the secondary fluid supplied to the temperature control target to the previously set temperature.

[0065] In this way, by changing the opening of the cooling expansion valve 6 or the heating expansion valve 9 to change the flow rate of refrigerant supplied to the heat exchanger 7, if the pressure of the refrigerant in the low-pressure circuit in the primary side circulation circuit 3 (low pressure) differs from a preset pressure, the rotation speed of the compressor 4 is adjusted to adjust the refrigerant discharge amount from the compressor 4, thereby returning the pressure of the refrigerant in the low-pressure circuit (low pressure) to the preset pressure.

[0066] Next, by adjusting the rotation speed of compressor 4 to adjust the amount of refrigerant discharged from compressor 4, when the temperature of the secondary fluid supplied to the temperature control target changes, the opening of either cooling expansion valve 6 or heating expansion valve 9 is slightly changed to return the temperature of the secondary fluid supplied to the temperature control target to the set temperature.

[0067] To explain this relationship in more detail using cooling operation as an example, when the cooling load in various processes of the temperature control target increases from a constant load during cooling operation, the temperature of the secondary fluid returning from the temperature control target increases, and therefore the temperature of the secondary fluid supplied to the temperature control target increases above the set temperature.

[0068] In such a case, the opening of the cooling expansion valve 6 is increased to increase the cooling capacity of the heat exchanger 7, thereby returning the temperature of the secondary side fluid to the set temperature.

[0069] Next, if the opening of the cooling expansion valve 6 is widened to increase the cooling capacity in the heat exchanger 7 and return the temperature of the secondary fluid to the set temperature, the pressure of the refrigerant (low pressure) in the low pressure circuit from the heat exchanger 7 to the compressor 4 will rise above the set pressure.

[0070] In such a case, the rotation speed of the compressor 4 is adjusted to adjust the amount of refrigerant discharged from the compressor 4, thereby returning the pressure of the refrigerant in the low pressure circuit (low pressure) to a preset pressure.

[0071] Next, when the rotation speed of compressor 4 is increased to match the pressure of the refrigerant in the low-pressure circuit (low-pressure pressure) to a set value, the amount of refrigerant discharged from compressor 4 increases. However, this increase may be excessive relative to the refrigerant flow rate required to bring the temperature of the secondary fluid supplied to the temperature control target to the set temperature, which may cause the temperature of the secondary fluid supplied to the temperature control target to be lower than the set temperature.

[0072] In such a case, the opening of the cooling expansion valve 6 is slightly narrowed to reduce the cooling capacity of the heat exchanger 7, and the temperature of the secondary fluid supplied to the temperature adjustment target is returned to the set temperature.

[0073] In this way, in the temperature control method of this embodiment, when the temperature of the secondary fluid returning to the heat exchanger during cooling or heating operation is different from the set temperature due to a decrease or increase in the load in various processes to be temperature-controlled, first, the opening degree of either the cooling expansion valve 6 or the heating expansion valve 9 is changed to return the temperature of the secondary fluid supplied to the temperature control target to a preset temperature (temperature control), and then, if the low pressure of the refrigerant is different from the preset pressure, the rotation speed of the compressor 4 is adjusted to return the low pressure of the refrigerant to the preset pressure (pressure control), and then, if the temperature of the secondary fluid supplied to the temperature control target changes due to the adjustment of the rotation speed of the compressor 4, the opening degree of either the cooling expansion valve 6 or the heating expansion valve 9 is slightly changed to return the temperature of the secondary fluid supplied to the temperature control target to the set temperature. That is, the temperature of the secondary fluid supplied to the temperature control target is stabilized by alternately controlling the temperature of the secondary fluid and the low pressure in the low pressure circuit. Therefore, unlike methods that simply control the temperature of the secondary fluid by manipulating only the opening degree of the expansion valve, the present invention makes it possible to simply simultaneously perform stable temperature control and ensure a minimum amount of refrigerant circulation.

[0074] Conventionally, heating control has been achieved by switching a four-way valve. This method provides a good heating COP for heating operation, but the temperature control of various processes in semiconductor manufacturing, which is the subject of this invention, requires constant temperature regulation, and this cannot be achieved with a system that switches a four-way valve. However, in this embodiment, the temperature control can be switched continuously and without loss, from cooling operation to heating operation and from heating operation to cooling operation.

[0075] According to the experiment conducted by the inventor, when the temperature of the secondary fluid returning to the heat exchanger 7 differs from the set temperature, as described above, (1) By changing the opening of either the cooling expansion valve 6 or the heating expansion valve 9, the flow rate of the refrigerant supplied to the heat exchanger 7 is changed, thereby changing the cooling capacity or heating capacity of the heat exchanger 7, and the temperature of the secondary fluid supplied to the temperature control target is returned to a preset temperature, and then (2) By changing the opening of the cooling expansion valve 6 or the heating expansion valve 9 to change the flow rate of the refrigerant supplied to the heat exchanger 7, when the low pressure of the refrigerant in the primary side circulation circuit 3 differs from a preset pressure, the rotation speed of the compressor 4 is adjusted to adjust the amount of refrigerant discharged from the compressor 4, thereby returning the low pressure of the refrigerant in the low pressure circuit to the preset pressure; (3) By adjusting the rotation speed of the compressor 4 to adjust the amount of refrigerant discharged from the compressor 4, the opening degree of either the cooling expansion valve 6 or the heating expansion valve 9 is slightly changed when the temperature of the secondary fluid supplied to the temperature control target changes. It was confirmed that by performing this operation, the temperature of the secondary fluid returning to the heat exchanger 7 and the measured value of the low pressure of the refrigerant in the primary side circulation circuit 3 enter a stable region with respect to the set value. However, in order to further completely stabilize the temperature of the secondary fluid returning to the heat exchanger 7 and the measured value of the low pressure of the refrigerant in the primary side circulation circuit 3 with respect to the set value, the above operations (1), (2), and (3) can be repeated until the temperature of the secondary fluid returning to the heat exchanger 7 and the measured value of the low pressure of the refrigerant in the primary side circulation circuit 3 become completely stable with respect to the set value.

[0076] Furthermore, in this embodiment, in the case where the temperature of the secondary fluid supplied to the temperature adjustment target is in a steady state where it is maintained at the set temperature, if the low pressure of the refrigerant in the low pressure circuit between the heat exchanger 7 and the compressor 4 in the primary side circulation circuit 3 slightly deviates from the pressure set value due to some influence, the rotation speed of the compressor 4 is instantly adjusted to immediately return the low pressure to the set value. Note that, at this time, the discharge amount of the refrigerant changes by adjusting the rotation speed of the compressor 4, but since the heat exchange is not easily affected by a slight change in the refrigerant flow rate, the temperature of the secondary fluid supplied to the temperature adjustment target can be maintained stable. [Industrial Applicability]

[0077] The temperature control method of the present invention is a method of using a chiller to control the temperature of various processes in the manufacture of semiconductors, etc., and enables costs to be reduced by performing high-precision temperature control while eliminating waste of refrigerant flow rate for adjusting the temperature of the secondary fluid, and therefore can be applied to all methods of using a chiller to supply a secondary fluid at a predetermined temperature to a temperature-controlled object. [Explanation of symbols]

[0078] 1 Temperature control system 2 Chiller 3 Primary circulation circuit 4. Compressor 5. Condenser 6 Cooling expansion valve 7 Heat exchanger 8 Heating circuit 9. Thermal expansion valve 10 Accumulator 11 Cooling water circulation circuit 12 Secondary circulation circuit 1201 Cold water supply line 1202 Cold water return channel 13 Temperature Sensor 14 Pressure Sensor 15 Control Means 16 Pump

Claims

1. a secondary circulation circuit (12) for repeating a cycle of circulating a secondary fluid, supplying the secondary fluid controlled to a predetermined temperature to a temperature control target, and controlling the secondary fluid circulated from the temperature control target to a predetermined temperature and then supplying it to the temperature control target; The present invention relates to a heat exchanger (7) that controls the temperature of a secondary fluid to be supplied to a temperature control target at a predetermined temperature by connecting the secondary fluid to a primary circulation circuit (3) and the refrigerant supplied via the primary circulation circuit (3) with the secondary fluid, a compressor (4) that compresses the vaporized refrigerant to a high pressure, a condenser (5) that condenses the refrigerant that has been pressurized by the compressor (4) through heat exchange, and a condenser (5) that reduces the pressure of the refrigerant liquefied by the condenser (5) to a low pressure and performs heat exchange. a cooling expansion valve (6) that supplies a high-temperature refrigerant pressurized by the compressor (4) to the heat exchanger (7); a heating circuit (8) that connects between the compressor (4) and the condenser (5) and between the cooling expansion valve (6) and the heat exchanger (7) in the primary side circulation circuit (3) and supplies the high-temperature refrigerant to the heat exchanger (7) and that is pressurized by the compressor (4); and a heating expansion valve (9) that is disposed in the heating circuit (8), a chiller (2) that uses a variable speed compressor as the compressor (4) and controls a secondary side fluid circulated from a temperature control target to a predetermined temperature; A temperature sensor (13) for measuring the temperature of a secondary fluid supplied to a temperature control target; a pressure sensor for measuring a refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary circulation circuit (3); A temperature control method for controlling a temperature of a secondary fluid supplied to a temperature control target to a predetermined temperature in order to control temperatures of various processes as a temperature control target to a predetermined temperature using a temperature control system including the following: The temperature of the secondary fluid to be supplied to the temperature control target and the refrigerant pressure between the heat exchanger (7) and the compressor (4) are set in advance; When cooling the secondary side fluid, the refrigerant is circulated while passing through the heat exchanger (7), the compressor (4), the condenser (5), and the cooling expansion valve (6) to control the supply temperature of the secondary side fluid to various processes, and when heating the secondary side fluid, the refrigerant is circulated while passing through the heat exchanger (7), the compressor (4), and the heating expansion valve (9) to control the supply temperature of the secondary side fluid to various processes, and the output of the cooling expansion valve (6) and the output of the heating expansion valve (9) cross each other near their lower limit values ​​to prevent both the opening of the cooling expansion valve (6) and the opening of the heating expansion valve (9) from being fully closed, and the circulation amount of the refrigerant circulating in the primary side circulation circuit (3) is prevented from falling below a minimum circulation amount. When the temperature of the secondary fluid supplied to the temperature control target differs from the set temperature, By changing the opening degree of either the cooling expansion valve (6) or the heating expansion valve (9), the temperature of the secondary fluid to be supplied to the temperature adjustment target is returned to the preset temperature; When the opening degree of the cooling expansion valve (6) or the heating expansion valve (9) is changed so that the refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary side circulation circuit (3) differs from a preset pressure, the rotation speed of the compressor (4) is adjusted to adjust the amount of refrigerant discharged from the compressor (4) so ​​that the refrigerant pressure between the heat exchanger (7) and the compressor (4) is returned to the preset pressure; When the temperature of the secondary fluid supplied to the temperature adjustment target changes by adjusting the rotation speed of the compressor (4) to adjust the amount of refrigerant discharged from the compressor (4), the temperature of the secondary fluid supplied to the temperature adjustment target is returned to the set temperature by slightly changing the opening of either the cooling expansion valve (6) or the heating expansion valve (9). A temperature control method comprising:

2. a secondary circulation circuit (12) for repeating a cycle of circulating a secondary fluid, supplying the secondary fluid controlled to a predetermined temperature to a temperature control target, and controlling the secondary fluid circulated from the temperature control target to a predetermined temperature and then supplying it to the temperature control target; The present invention relates to a heat exchanger (7) that controls the temperature of a secondary fluid to be supplied to a temperature control target at a predetermined temperature by connecting the secondary fluid to a primary circulation circuit (3) and the refrigerant supplied via the primary circulation circuit (3) with the secondary fluid, a compressor (4) that compresses the vaporized refrigerant to a high pressure, a condenser (5) that condenses the refrigerant that has been pressurized by the compressor (4) through heat exchange, and a condenser (5) that reduces the pressure of the refrigerant liquefied by the condenser (5) to a low pressure and performs heat exchange. a cooling expansion valve (6) that supplies a high-temperature refrigerant pressurized by the compressor (4) to the heat exchanger (7); a heating circuit (8) that connects between the compressor (4) and the condenser (5) and between the cooling expansion valve (6) and the heat exchanger (7) in the primary side circulation circuit (3) and supplies the high-temperature refrigerant to the heat exchanger (7) and that is pressurized by the compressor (4); and a heating expansion valve (9) that is disposed in the heating circuit (8), a chiller (2) that uses a variable speed compressor as the compressor (4) and controls a secondary side fluid circulated from a temperature control target to a predetermined temperature; A temperature sensor (13) for measuring the temperature of a secondary fluid supplied to a temperature control target; a pressure sensor for measuring a refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary circulation circuit (3); A temperature control method for controlling a temperature of a secondary fluid supplied to a temperature control target to a predetermined temperature in order to control temperatures of various processes as a temperature control target to a predetermined temperature using a temperature control system including the following: The temperature of the secondary fluid to be supplied to the temperature control target and the refrigerant pressure between the heat exchanger (7) and the compressor (4) are set in advance; When cooling the secondary side fluid, the refrigerant is circulated while passing through the heat exchanger (7), the compressor (4), the condenser (5), and the cooling expansion valve (6) to control the supply temperature of the secondary side fluid to various processes, and when heating the secondary side fluid, the refrigerant is circulated while passing through the heat exchanger (7), the compressor (4), and the heating expansion valve (9) to control the supply temperature of the secondary side fluid to various processes, and the output of the cooling expansion valve (6) and the output of the heating expansion valve (9) cross each other near their lower limit values ​​to prevent both the opening of the cooling expansion valve (6) and the opening of the heating expansion valve (9) from being fully closed, and the circulation amount of the refrigerant circulating in the primary side circulation circuit (3) is prevented from falling below a minimum circulation amount. When the temperature of the secondary fluid supplied to the temperature control target differs from the set temperature, In step 1, the opening degree of either the cooling expansion valve (6) or the heating expansion valve (9) is changed to return the temperature of the secondary fluid to be supplied to the temperature adjustment target to the preset temperature; When the opening degree of the cooling expansion valve (6) or the heating expansion valve (9) is changed so that the refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary side circulation circuit (3) differs from a preset pressure, in step 2, the rotation speed of the compressor (4) is adjusted to adjust the amount of refrigerant discharged from the compressor (4) so ​​that the refrigerant pressure between the heat exchanger (7) and the compressor (4) is returned to the preset pressure; When the temperature of the secondary fluid supplied to the temperature adjustment target changes by adjusting the rotation speed of the compressor (4) to adjust the amount of refrigerant discharged from the compressor (4), in step 3, the opening of either the cooling expansion valve (6) or the heating expansion valve (9) is slightly changed to return the temperature of the secondary fluid supplied to the temperature adjustment target to the set temperature; and repeating steps (1), (2), and (3) thereafter until the measured values ​​of the temperature of the secondary fluid supplied to the temperature control target and the refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary circulation circuit (3) become completely stable with respect to the preset temperature and pressure.

3. 3. The temperature control method according to claim 1, wherein the operations of the compressor (4), the cooling expansion valve (6), and the heating expansion valve (9) are automatically controlled by a control means based on the measurement results of the temperature sensor (13) and the pressure sensor (14).

4. 3. The temperature control method according to claim 1, further comprising the step of: adjusting the rotation speed of the compressor (4) to return the refrigerant pressure to the set value when a slight deviation occurs in a refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary side circulation circuit (3) from a preset pressure while the temperature of the secondary side fluid supplied to the temperature control target is maintained at a set temperature.

5. 4. The temperature control method according to claim 3, characterized in that, when the temperature of the secondary fluid supplied to the temperature control target is maintained at a set temperature, if a refrigerant pressure between the heat exchanger (7) and the compressor (4) in the primary circulation circuit (3) slightly deviates from a preset pressure, the rotation speed of the compressor (4) is adjusted to return the refrigerant pressure to the set value.

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