Temperature control device

Abstract

To provide a temperature control device which can prevent liquid compression and can enhance a coefficient of performance and cooling efficiency.SOLUTION: A temperature control device 2 has a basic passage 4, wherein the basic passage 4 includes a compressor 14 which is arranged in a first passage 12 and compresses a refrigerant, a first pressure sensor 16 for detecting pressure of CO2 refrigerant sent to the compressor 14, a second passage 18 for sending out the compressed refrigerant, a third passage 28 having an internal heat exchanger 26 to which the refrigerant is sent from a first condenser 20, a branch portion 34 at which the third passage 28 branches into a fourth passage 30 and a fifth passage 32, a first variable expansion valve 36 and a first evaporator 38 which are disposed in the fourth passage 30, a second variable expansion valve 40 and a second evaporator 42 which are disposed in the fifth passage 32, and a sixth passage 44 in which the fourth passage 30 and the fifth passage 32 are merged and the refrigerant is sent to the internal heat exchanger 26 so that heat is applied to the refrigerant and the liquid refrigerant is eliminated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temperature control device that controls the temperature of circulating water and also controls the temperature of processing water. [Background technology]

[0002] A wafer has multiple devices such as ICs and LSIs formed on its surface, separated by planned dividing lines. The back surface is ground by a grinding machine to form the wafer to a specified thickness, and then the wafer is divided into individual device chips using a dicing machine, laser processing machine, etc. Each divided device chip is used in electrical equipment such as mobile phones and personal computers.

[0003] When processing a wafer, if the spindle unit to which the processing tools constituting the grinding or dicing device are attached generates heat and expands, high-precision grinding or cutting becomes impossible. For this reason, a cooling device is used to control the temperature of the spindle unit to a constant value (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-40396 Summary of the Invention [Problem to be solved by the invention]

[0005] The cooling device described in Patent Document 1 uses CO2 as a refrigerant and can achieve high cooling efficiency. However, if the temperature of functional water used in processing equipment (including disposable processing water such as cutting water and circulating water used for cooling spindles, etc.) is set low, the refrigerant sucked into the compressor may not completely vaporize, resulting in liquid compression and potentially shortening the compressor's lifespan.

[0006] On the other hand, when grinding or dicing equipment is used in cold regions, the temperature of the functional water may drop below the specified temperature. In such cases, it is necessary to use an electric heater to heat the functional water to the specified temperature. However, the heating capacity of an electric heater corresponds to the power consumption, and the coefficient of performance (heating capacity / power consumption) is a small 1.

[0007] An object of the present invention is to provide a temperature control device that can improve the coefficient of performance and cooling efficiency while preventing liquid compression. [Means for solving the problem]

[0008] According to the present invention, there is provided the following temperature control device that solves the above problems: "A temperature control device that controls the temperature of circulating water and the temperature of processing water, a compressor disposed in a first path for feeding the CO2 refrigerant and compressing the CO2 refrigerant; a first pressure sensor disposed in the first path and configured to detect the pressure of the CO2 refrigerant fed to the compressor; a second path for delivering the CO2 refrigerant compressed by the compressor; a first condenser disposed in the second path; a variable valve disposed between the compressor and the first condenser; a second pressure sensor disposed between the variable valve and the first condenser and configured to detect the pressure of the CO refrigerant; a third passage including an internal heat exchanger into which the CO refrigerant is delivered from the first condenser; a branching portion that branches the third path into a fourth path and a fifth path; a first variable expansion valve and a first evaporator disposed in the fourth path; a second variable expansion valve and a second evaporator disposed in the fifth passage; a sixth path where the fourth path and the fifth path join and send the CO2 refrigerant to the internal heat exchanger to give heat to the CO2 refrigerant and cause the liquid CO2 refrigerant to disappear, In the basic path, the CO refrigerant is sent from the internal heat exchanger to the compressor via the first path, moreover, a circulating water path communicating with the first evaporator to control the temperature of the circulating water; a processing water passage communicating with the second evaporator to control the temperature of the processing water; A temperature control device including a control means is provided.

[0009] Preferably, a heating path is provided that is connected to the second path from the compressor to the variable valve and that is connected to the second path from the variable valve to the first condenser, and the heating path includes a third pressure sensor, a second condenser, and a variable heating control valve; The processing water path is connected to the second condenser, and the CO2 refrigerant provides heat to the processing water.

[0010] The first condenser is provided with an industrial water passage through which industrial water flows to remove heat from the CO2 refrigerant, the industrial water passage includes a first water control valve for supplying industrial water to the first condenser and an outlet for discharging the industrial water, and a second water control valve between the first condenser and the outlet; a third evaporator is disposed between the second water control valve and the outlet; the third evaporator is in communication with the branch portion via a third variable expansion valve and is in communication with the sixth path; It is desirable that the CO2 refrigerant, to which heat has been given from the industrial water in the third evaporator, gives heat to the processing water in the second condenser.

[0011] It is preferable that a bypass path is provided connecting the second path between the compressor and the variable valve to the sixth path before the internal heat exchanger, and that the bypass path is equipped with a variable bypass valve.

[0012] When there is a risk that the rotation speed of the compressor will fall below the minimum allowable rotation speed, the control means can maintain the rotation speed of the compressor at the minimum allowable rotation speed or increase the rotation speed of the compressor by adjusting the opening of the variable bypass valve.

[0013] When the temperature difference between the temperature of the industrial water flowing into the third evaporator and the temperature of the industrial water flowing out of the third evaporator is greater than a predetermined value, the control means adjusts the opening of the second water control valve so that the temperature difference is within the predetermined value in order to compensate for the insufficient flow rate of the industrial water, thereby providing heat to the CO2 refrigerant and improving the heat exchange rate of the third evaporator.

[0014] The control means preferably adjusts the opening of the first variable expansion valve so that the temperature of the circulating water becomes a predetermined temperature, adjusts the opening of the second variable expansion valve so that the temperature of the processing water becomes a predetermined temperature, and also adjusts the rotation speed of the compressor so that the detection value of the second pressure sensor becomes a predetermined pressure value relative to the detection value of the first pressure sensor.

[0015] The control means may fully close the second variable expansion valve and adjust the opening of the variable heating control valve so that the processing water is heated to a predetermined temperature.

[0016] When adjusting the opening of the variable heating control valve, the control means desirably adjusts the opening of the variable valve so that the difference between the detection values of the second pressure sensor and the third pressure sensor becomes a predetermined value, thereby maintaining a constant amount of heating of the processing water.

[0017] It is preferable that the control means opens the first water control valve to send industrial water to the first condenser, remove heat from the CO2 refrigerant, send the industrial water to the third evaporator to give heat to the CO2 refrigerant, and further give heat to the processing water in the second condenser.

[0018] The control means can adjust the opening of the second water control valve so that the difference between the temperature of the industrial water flowing into the third evaporator and the temperature of the industrial water flowing out of the third evaporator becomes a predetermined value, thereby preventing a decrease in the efficiency of the third evaporator. [Effects of the Invention]

[0019] The temperature control device of the present invention comprises: A temperature control device that controls the temperature of circulating water and the temperature of processing water, a compressor disposed in a first path for feeding the CO2 refrigerant and compressing the CO2 refrigerant; a first pressure sensor disposed in the first path and configured to detect the pressure of the CO2 refrigerant fed to the compressor; a second path for delivering the CO2 refrigerant compressed by the compressor; a first condenser disposed in the second path; a variable valve disposed between the compressor and the first condenser; a second pressure sensor disposed between the variable valve and the first condenser and configured to detect the pressure of the CO refrigerant; a third passage including an internal heat exchanger into which the CO refrigerant is delivered from the first condenser; a branching portion that branches the third path into a fourth path and a fifth path; a first variable expansion valve and a first evaporator disposed in the fourth path; a second variable expansion valve and a second evaporator disposed in the fifth passage; a sixth path where the fourth path and the fifth path join and send the CO2 refrigerant to the internal heat exchanger to give heat to the CO2 refrigerant and cause the liquid CO2 refrigerant to disappear, In the basic path, the CO refrigerant is sent from the internal heat exchanger to the compressor via the first path, moreover, a circulating water path communicating with the first evaporator to control the temperature of the circulating water; a processing water passage communicating with the second evaporator to control the temperature of the processing water; Since the control means is included, it is possible to prevent liquid compression while improving the coefficient of performance and cooling efficiency. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a circuit diagram of a temperature control device according to the present invention. [Figure 2]Circuit diagram showing the flow of CO2 refrigerant when cooling circulating water and heating processing water. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a temperature control device according to the present invention will now be described with reference to the drawings.

[0022] (Temperature control device 2) 1 shows a temperature control device 2 that controls the temperature of circulating water and the temperature of processing water. The temperature control device 2 includes a basic path 4 (thick solid line) through which a CO2 refrigerant flows, a circulating water path 6 (thin dashed line) through which circulating water flows, a processing water path 8 (thin dashed line) through which processing water flows, and control means 10. Note that the circulating water and processing water may be, for example, pure water.

[0023] (Basic Route 4) The basic path 4 includes a compressor 14 arranged in a first path 12 that sends CO2 refrigerant and compresses the CO2 refrigerant, and a first pressure sensor 16 arranged in the first path 12 that detects the pressure of the CO2 refrigerant sent to the compressor 14.

[0024] (First Route 12) A first path 12 shown in the lower left portion of FIG. 1 is connected to an intake port 14a of a compressor 14, and CO2 refrigerant is sent from the first path 12 to the compressor 14.

[0025] (Compressor 14) The compressor 14 compresses the CO2 refrigerant circulating through the temperature control device 2. As shown in FIG. 1, the motor 14b that drives the compressor 14 is provided with an inverter 14c. The inverter 14c changes the frequency of the power supplied to the motor 14b within a predetermined range (for example, 20 Hz to 120 Hz). This changes the rotation speed of the motor 14b, and also changes the rotation speed of the compressor 14 within the range of allowable rotation speeds (between the minimum rotation speed and the maximum rotation speed). The inverter 14c is electrically connected to the control means 10 and is controlled by the control means 10.

[0026] (First pressure sensor 16) The first pressure sensor 16 is disposed upstream of the compressor 14 (on the suction port 14a side) and detects the pressure of the CO2 refrigerant fed into the compressor 14. The detected value of the first pressure sensor 16 is sent to the control means 10.

[0027] The basic path 4 also includes a second path 18 for sending out the CO2 refrigerant compressed by the compressor 14, a first condenser 20 arranged in the second path 18, a variable valve 22 arranged between the compressor 14 and the first condenser 20, and a second pressure sensor 24 arranged between the variable valve 22 and the first condenser 20 for detecting the pressure of the CO2 refrigerant.

[0028] (Second Route 18) The second path 18 is connected to the discharge port 14d of the compressor 14, and the CO2 refrigerant compressed by the compressor 14 is sent to the second path 18.

[0029] (First condenser 20) The first condenser 20 cools and liquefies the CO2 refrigerant compressed by the compressor 14 and carrying heat of compression. The first condenser 20 is formed with a refrigerant passage 20a through which the CO2 refrigerant passes and an industrial water passage 20b through which industrial water passes. The first condenser 20 cools the high-temperature CO2 refrigerant discharged from the compressor 14 by using the industrial water by performing heat exchange between the CO2 refrigerant in the refrigerant passage 20a and the industrial water in the industrial water passage 20b.

[0030] (Variable valve 22) The variable valve 22 adjusts the flow rate of the CO2 refrigerant sent from the compressor 14 to the first condenser 20. A motor 22a, which adjusts the opening degree of the variable valve 22, is electrically connected to the control means 10. The opening degree of the variable valve 22 is adjusted by the motor 22a based on instructions from the control means 10.

[0031] (Second pressure sensor 24) The second pressure sensor 24 is disposed in the second path 18 between the variable valve 22 and the first condenser 20, and detects the pressure of the CO2 refrigerant sent to the first condenser 20. The detected value of the second pressure sensor 24 is sent to the control means 10.

[0032] Furthermore, the basic path 4 includes a third path 28 having an internal heat exchanger 26 to which the CO2 refrigerant is sent from the first condenser 20, a branching section 34 that branches the third path 28 into a fourth path 30 and a fifth path 32, a first variable expansion valve 36 and a first evaporator 38 arranged in the fourth path 30, a second variable expansion valve 40 and a second evaporator 42 arranged in the fifth path 32, and a sixth path 44 where the fourth path 30 and the fifth path 32 join and which sends the CO2 refrigerant to the internal heat exchanger 26, gives heat to the CO2 refrigerant, and causes the liquid CO2 refrigerant to disappear.

[0033] (internal heat exchanger 26) The internal heat exchanger 26 is formed with a first passage 26a into which the CO2 refrigerant is sent from the first condenser 20 and a second passage 26b into which the CO2 refrigerant is sent from the first evaporator 38 and the second evaporator 42. The internal heat exchanger 26 exchanges heat between the CO2 refrigerant in the first passage 26a and the CO2 refrigerant in the second passage 26b. As a result, heat is transferred from the CO2 refrigerant in the first passage 26a to the CO2 refrigerant in the second passage 26b, and any liquid CO2 refrigerant remaining in the CO2 refrigerant in the second passage 26b disappears.

[0034] (Third path 28, fourth path 30, fifth path 32, branch 34) The third path 28 is connected to the refrigerant path 20a of the first condenser 20, and the CO2 refrigerant cooled and liquefied by the first condenser 20 is sent to the third path 28. The third path 28 is also connected to the first path 26a of the internal heat exchanger 26. The third path 28 continues from the first path 26a of the internal heat exchanger 26 to a branching point 34, where it branches into a fourth path 30 and a fifth path 32.

[0035] (First variable expansion valve 36) The first variable expansion valve 36 is disposed in the fourth path 30 and expands the CO2 refrigerant that has passed through the internal heat exchanger 26. A motor 36a that adjusts the aperture of the first variable expansion valve 36 is electrically connected to the control means 10. The aperture of the first variable expansion valve 36 is adjusted by the motor 36a based on instructions from the control means 10.

[0036] (First evaporator 38) The first evaporator 38 is disposed downstream of the first variable expansion valve 36 in the fourth path 30. The first evaporator 38 is formed with a refrigerant passage 38a through which the CO2 refrigerant passes and a circulating water passage 38b through which the circulating water passes. The first evaporator 38 performs heat exchange between the CO2 refrigerant in the refrigerant passage 38a expanded by the first variable expansion valve 36 and the circulating water in the circulating water passage 38b. As a result, the CO2 refrigerant absorbs heat from the circulating water and vaporizes, while the circulating water is cooled. However, some of the CO2 refrigerant that passes through the refrigerant passage 38a may remain liquid.

[0037] (Second variable expansion valve 40) The second variable expansion valve 40 is disposed in the fifth path 32 and expands the CO2 refrigerant that has passed through the internal heat exchanger 26. A motor 40a that adjusts the aperture of the second variable expansion valve 40 is electrically connected to the control means 10. The aperture of the second variable expansion valve 40 is adjusted by the motor 40a based on instructions from the control means 10.

[0038] (Second evaporator 42) The second evaporator 42 is disposed downstream of the second variable expansion valve 40 in the fifth path 32. The second evaporator 42 has a refrigerant passage 42a through which the CO2 refrigerant passes and a processing water passage 42b through which the processing water passes. The second evaporator 42 performs heat exchange between the CO2 refrigerant in the refrigerant passage 42a expanded by the second variable expansion valve 40 and the processing water in the processing water passage 42b. As a result, the CO2 refrigerant absorbs heat from the processing water and vaporizes, and the processing water is cooled. However, some of the CO2 refrigerant that passes through the refrigerant passage 42a may remain liquid.

[0039] (Sixth Route 44) The sixth path 44 is connected to the fourth path 30 and the fifth path 32 at a junction 46. The sixth path 44 is also connected to the second path 26b of the internal heat exchanger 26. Therefore, the CO refrigerant that has passed through the first evaporator 38 and the second evaporator 42 is sent to the second path 26b of the internal heat exchanger 26 via the sixth path 44. In the internal heat exchanger 26, as described above, heat is transferred from the CO refrigerant in the first path 26a to the CO refrigerant in the second path 26b, and the liquid CO refrigerant remaining in the CO refrigerant in the second path 26b disappears. Then, the gaseous CO refrigerant that has passed through the second path 26b of the internal heat exchanger 26 is sent to the compressor 14 via the first path 12.

[0040] (Circulating water route 6) The circulating water path 6 is a path for controlling the temperature of the circulating water circulating between the first evaporator 38 and the processing device 48. The circulating water path 6 is connected to the circulating water passage 38b of the first evaporator 38 and to a circulating water passage (not shown) of the processing device 48. The circulating water passage of the processing device 48 is provided, for example, in a spindle unit that rotatably supports a spindle. The spindle is equipped with a cutting blade for cutting a workpiece such as a wafer, a grinding wheel for grinding the workpiece, and the like. Therefore, the spindle unit generates heat when processing is performed in the processing device 48. The circulating water in the circulating water path 6 absorbs heat from heat-generating components such as the spindle unit of the processing device 48 and is cooled in the first evaporator 38.

[0041] (Processing water route 8) The processing water path 8 is a path for controlling the temperature of the processing water supplied from the processing water supply source 50 to the processing device 48. The processing water path 8 is connected to the processing water passage 42b of the second evaporator 42 and also to a processing water spray nozzle (not shown) of the processing device 48. From the processing water spray nozzle of the processing device 48, processing water is sprayed toward a processing area where a workpiece such as a wafer is subjected to cutting or grinding, or the processing water is sprayed toward the wafer as a cleaning liquid when cleaning the processed wafer. The processing water sent from the processing water supply source 50 to the processing water path 8 is cooled in the second evaporator 42 and adjusted to an appropriate temperature before being supplied to the processing device 48.

[0042] (heating path 52) The processing water in the processing water path 8 can be heated as needed and adjusted to an appropriate temperature. When the processing device 48 is used in a cold region, the temperature of the processing water may fall below a predetermined temperature. Therefore, in this embodiment, a heating path 52 is provided to heat the processing water to a predetermined temperature. The heating path 52 is connected to the second path 18 extending from the compressor 14 to the variable valve 22 by a first connecting portion 52a, and is also connected to the second path 18 extending from the variable valve 22 to the first condenser 20 by a second connecting portion 52b. The heating path 52 also includes a third pressure sensor 54, a second condenser 56, and a variable heating control valve 58.

[0043] (Third pressure sensor 54) The third pressure sensor 54 is disposed upstream of the second condenser 56 in the heating path 52, and detects the pressure of the CO2 refrigerant sent to the second condenser 56. The detected value of the third pressure sensor 54 is sent to the control means 10.

[0044] (Second condenser 56) The second condenser 56 heats the processing water with the CO2 refrigerant compressed by the compressor 14 and carrying heat of compression. The second condenser 56 is formed with a refrigerant passage 56a through which the CO2 refrigerant passes and a processing water passage 56b through which the processing water passes. The refrigerant passage 56a is connected to the heating passage 52, and the processing water passage 56b is connected to the processing water passage 8. The second condenser 56 heats the processing water with the high-temperature CO2 refrigerant discharged from the compressor 14 by performing heat exchange between the CO2 refrigerant in the refrigerant passage 56a and the processing water in the processing water passage 56b. In this way, the processing water passage 8 in this embodiment is connected to the second condenser 56, so that the CO2 refrigerant imparts heat to the processing water.

[0045] (Variable Heat Control Valve 58) Variable heating control valve 58 adjusts the flow rate of CO2 refrigerant passing through heating path 52. Motor 58a, which adjusts the aperture of variable heating control valve 58, is electrically connected to control means 10. The aperture of variable heating control valve 58 is adjusted by motor 58a based on instructions from control means 10.

[0046] (Control means 10) The control means 10 is composed of a computer having a processor and memory. The control means 10 sets the pressure and temperature of the CO2 refrigerant based on instructions input by an operator (for example, the temperature of the circulating water and processing water used in the processing device 48). The control means 10 also controls the rotation speed of the compressor 14 and the openings of the first and second variable expansion valves 36, 40 so that the actual temperatures of the circulating water and processing water become the set temperatures (the temperatures input by the operator).

[0047] (Industrial water route 60) 1, the first condenser 20 is provided with an industrial water passage 60 through which industrial water flows to remove heat from the CO refrigerant. The industrial water passage 60 includes a first industrial water passage 60a connected to a first supply port 62a of an industrial water supply source 62 and the industrial water passage 20b of the first condenser 20, a second industrial water passage 60b connected to a second supply port 62b of the industrial water supply source 62, a junction 60c where the first industrial water passage 60a and the second industrial water passage 60b join, and an outlet 60d through which the industrial water is discharged. The industrial water passage 60 also includes a first water control valve 64 that supplies industrial water to the first condenser 20 and a second water control valve 66 between the first condenser 20 and the outlet 60d.

[0048] (First Water Control Valve 64) The first water control valve 64 is installed in the first industrial water path 60a, and controls the flow rate of industrial water sent from the industrial water supply source 62 to the industrial water passage 20b of the first condenser 20. A motor 64a that adjusts the opening of the first water control valve 64 is electrically connected to the control means 10, and the opening of the first water control valve 64 is adjusted by the motor 64a based on instructions from the control means 10. In this way, the flow rate of industrial water sent to the industrial water passage 20b of the first condenser 20 is controlled.

[0049] (Second Water Control Valve 66) The second water control valve 66 is installed in the second industrial water path 60b. A motor 66a that adjusts the opening of the second water control valve 66 is electrically connected to the control means 10, and the opening of the second water control valve 66 is adjusted by the motor 66a based on instructions from the control means 10. This controls the flow rate of industrial water sent to the second industrial water path 60b.

[0050] (Third evaporator 68) A third evaporator 68 is disposed between the second water control valve 66 and the outlet 60d. The third evaporator 68 is connected to the branching portion 34 via a third variable expansion valve 70 and to the sixth path 44. The third evaporator 68 is formed with a refrigerant passage 68a through which the CO2 refrigerant passes and an industrial water passage 68b through which the industrial water passes. The refrigerant passage 68a is connected to a seventh path 72 connected to the branching portion 34 and the junction 46. The third evaporator 68 exchanges heat between the CO2 refrigerant in the refrigerant passage 68a and the circulating water in the industrial water passage 68b. This transfers heat from the industrial water to the CO2 refrigerant.

[0051] (Third variable expansion valve 70) The third variable expansion valve 70 is disposed on the seventh path 72 upstream of the third evaporator 68. The third variable expansion valve 70 expands the CO2 refrigerant that has passed through the first passage 26a of the internal heat exchanger 26 and sends it to the third evaporator 68. A motor 70a that adjusts the opening degree of the third variable expansion valve 70 is electrically connected to the control means 10, and the opening degree of the third variable expansion valve 70 is adjusted by the motor 70a based on instructions from the control means 10.

[0052] (Bypass path 74, variable bypass valve 76) 1, a bypass path 74 is provided that connects the second path 18 between the compressor 14 and the variable valve 22 to the sixth path 44 immediately before the internal heat exchanger 26, and the bypass path 74 is equipped with a variable bypass valve 76. A motor 76a that adjusts the opening degree of the variable bypass valve 76 is electrically connected to the control means 10. The opening degree of the variable bypass valve 76 is adjusted by the motor 76a based on an instruction from the control means 10.

[0053] (Temperature sensor) The temperature control device 2 is provided with a plurality of temperature sensors that detect the temperatures of the circulating water, the processing water, and the industrial water. The detected values of the temperature sensors are all sent to the control means 10.

[0054] (First and second temperature sensors 78 and 80 detect the temperature of the circulating water) First and second temperature sensors 78, 80 for detecting the temperature of the circulating water are provided in the circulating water path 6. The first temperature sensor 78 detects the temperature of the circulating water flowing out from the first evaporator 38, and the second temperature sensor 80 detects the temperature of the circulating water flowing into the first evaporator 38.

[0055] (Third and fourth temperature sensors 82 and 84: detect the temperature of the processing water) The processing water path 8 is provided with a third temperature sensor 82 that detects the temperature of the processing water sent from the processing water supply source 50, and a fourth temperature sensor 84 that detects the temperature of the processing water supplied to the processing device 48. The third temperature sensor 82 is installed between the processing water supply source 50 and the second evaporator 42, and the fourth temperature sensor 84 is installed between the second condenser 56 and the processing device 48.

[0056] (Fifth and sixth temperature sensors 86 and 88: detect the temperature of industrial water) The industrial water path 60 is provided with a fifth temperature sensor 86 that detects the temperature of the industrial water flowing into the third evaporator 68, and a sixth temperature sensor 88 that detects the temperature of the industrial water flowing out from the third evaporator 68. The fifth temperature sensor 86 is installed between the junction 60c of the industrial water path 60 and the third evaporator 68, and the sixth temperature sensor 88 is installed between the third evaporator 68 and the outlet 60d.

[0057] (Temperature control device 2 operation) Next, we will explain the operation of the above-mentioned temperature control device 2. First, we will explain the case where the circulating water and processing water are cooled, and then we will explain the case where the circulating water is cooled and the processing water is heated.

[0058] (When cooling circulating water or processing water) In explaining the case of cooling the circulating water and processing water, the basic operation of the temperature control device 2 will be described first, and then the operation when increasing or decreasing the amount of cooling of the circulating water and processing water will be described.

[0059] (setting value) In the temperature control device 2, when an operator inputs an operation command into the control means 10, the values (set values) to be detected by each sensor are set in accordance with the input operation command. Specifically, the set temperature of the circulating water, the set temperature of the processing water, and the set pressure of the CO2 refrigerant are set. The set temperatures of the circulating water and the processing water are the temperatures input by the operator. Meanwhile, the set pressure of the CO2 refrigerant is determined by the control means 10 based on the set temperatures of the circulating water and the processing water.

[0060] (Circulating water temperature setting: first and second temperatures) The set temperature of the circulating water is set to a first temperature to be detected by the first temperature sensor 78 or a second temperature to be detected by the second temperature sensor 80. The first temperature is the set temperature of the circulating water flowing out from the first evaporator 38. The second temperature is the set temperature of the circulating water flowing into the first evaporator 38.

[0061] (Processing water temperature setting: third and fourth temperatures) Furthermore, a third temperature to be detected by the third temperature sensor 82 or a fourth temperature to be detected by the fourth temperature sensor 84 is set as the set temperature of the processing water. The third temperature is the set temperature of the processing water sent out from the processing water supply source 50. The fourth temperature is the set temperature of the processing water supplied to the processing device 48. If the processing water used in the processing device 48 is returned to the processing water supply source 50 via a pure water generator (not shown) or the like, the third temperature or the fourth temperature can be set. On the other hand, if the processing water used in the processing device 48 is not returned to the processing water supply source 50, the fourth temperature is set.

[0062] (CO2 refrigerant pressure settings: first and second pressure values) The control means 10 sets a first pressure value to be detected by the first pressure sensor 16 and a second pressure value to be detected by the second pressure sensor 24 as set pressures for the CO2 refrigerant. The first pressure value is the set pressure of the CO2 refrigerant flowing into the compressor 14 (the CO2 refrigerant before compression). The first pressure value may be, for example, about 4 MPa (absolute pressure). On the other hand, the second pressure value is the set pressure of the CO2 refrigerant flowing out from the compressor 14 (the CO2 refrigerant after compression). The second pressure value may be set to a pressure (for example, about 10 MPa (absolute pressure)) that exceeds the critical pressure of 7.38 MPa (absolute pressure) at which the CO2 refrigerant goes into a supercritical state.

[0063] Once the set temperatures of the circulating water and processing water and the set pressure of the CO2 refrigerant have been set, the actual processing water temperature is compared with the set temperature to determine whether to cool or heat the processing water. If the actual processing water temperature is higher than the set temperature, the control means 10 cools the processing water. As described above, the circulating water is constantly cooled in the first evaporator 38 to remove heat from heat-generating components such as the spindle unit in the processing device 48.

[0064] When cooling the circulating water and processing water, the control means 10 normally opens the variable valve 22, the first and second variable expansion valves 36 and 40, and the first water control valve 64, while closing the variable bypass valve 76, the variable heating control valve 58, the third variable expansion valve 70, and the second water control valve 66. As a result, the CO2 refrigerant circulates through the basic path 4, as shown by the thick solid line in FIG. 1. The circulating water also circulates through the circulating water path 6, and the processing water is supplied to the processing device 48 from the processing water source 50 via the processing water path 8. Industrial water is sent from the industrial water source 62 to the first industrial water path 60a.

[0065] (CO2 refrigerant flow) The flow of CO2 refrigerant and the function of each device will be explained below. When cooling circulating water or process water, the CO2 refrigerant flows into the compressor 14 from the first path 12, is compressed by the compressor 14, and flows out into the second path 18. The high-temperature, high-pressure CO2 refrigerant that flows out into the second path 18 passes through a variable valve 22 and then flows into the refrigerant passage 20a of the first condenser 20. In the first condenser 20, heat exchange occurs between the CO2 refrigerant in the refrigerant passage 20a and the industrial water in the industrial water passage 20b, and the CO2 refrigerant is cooled by the industrial water.

[0066] The CO2 refrigerant that has passed through the first condenser 20 passes through a third path 28 and flows into a first path 26a of the internal heat exchanger 26. The CO2 refrigerant that has flowed into the first path 26a gives heat to the CO2 refrigerant passing through the second path 26b, and then branches into a fourth path 30 and a fifth path 32 at a branching point 34.

[0067] The CO2 refrigerant that has advanced to the fourth path 30 flows into the first variable expansion valve 36 and is expanded in the first variable expansion valve 36, thereby decreasing its pressure and temperature. The CO2 refrigerant that has passed through the first variable expansion valve 36 flows into the refrigerant passage 38a of the first evaporator 38. In the first evaporator 38, heat exchange occurs between the CO2 refrigerant in the refrigerant passage 38a and the circulating water in the circulating water passage 38b. As a result, the CO2 refrigerant absorbs heat from the circulating water and is vaporized, and the circulating water is cooled by the CO2 refrigerant. However, some of the CO2 refrigerant that has passed through the first evaporator 38 may remain liquid.

[0068] Meanwhile, the CO2 refrigerant that has advanced to the fifth path 32 flows into the second variable expansion valve 40 and is expanded by the second variable expansion valve 40, thereby decreasing its pressure and temperature. The CO2 refrigerant that has passed through the second variable expansion valve 40 flows into the refrigerant passage 42a of the second evaporator 42. In the second evaporator 42, heat exchange occurs between the CO2 refrigerant in the refrigerant passage 42a and the processing water in the processing water passage 42b. As a result, the CO2 refrigerant absorbs heat from the processing water and vaporizes, and the processing water is cooled by the CO2 refrigerant. However, some of the CO2 refrigerant that has passed through the second evaporator 42 may remain liquid.

[0069] The CO2 refrigerant that has passed through the first evaporator 38 and the CO2 refrigerant that has passed through the second evaporator 42 join at a joining point 46 and then flow into the second passage 26b of the internal heat exchanger 26 via a sixth passage 44. The CO2 refrigerant that has flowed into the second passage 26b absorbs heat from the CO2 refrigerant that has passed through the first passage 26a. Therefore, even if liquid remains in the CO2 refrigerant that has passed through the first and second evaporators 38 and 42, all of the liquid in the CO2 refrigerant becomes gas in the second passage 26b of the internal heat exchanger 26. The CO2 refrigerant that has passed through the second passage 26b of the internal heat exchanger 26 then passes through the first passage 12 and is drawn into the compressor 14.

[0070] As described above, in this embodiment, by circulating the CO2 refrigerant through the basic path 4, the circulating water is cooled in the first evaporator 38, and the processing water is cooled in the second evaporator 42. Furthermore, in the internal heat exchanger 26 of this embodiment, the CO2 refrigerant that has passed through the first and second evaporators 38, 42 absorbs heat from the CO2 refrigerant that has passed through the first condenser 20. As a result, the liquid CO2 refrigerant remaining in the CO2 refrigerant that has passed through the first and second evaporators 38, 42 disappears. As a result, all of the CO2 refrigerant drawn into the compressor 14 becomes gas, reducing the load on the compressor 14. Therefore, this embodiment solves the problem of shortening the lifespan of the compressor 14 by compressing liquid CO2 refrigerant.

[0071] (Improved cooling efficiency) The control means 10 of this embodiment adjusts the opening of the first variable expansion valve 36 so that the temperature of the circulating water becomes a predetermined temperature, adjusts the opening of the second variable expansion valve 40 so that the temperature of the processing water becomes a predetermined temperature, and also adjusts the rotation speed of the compressor 14 so that the detection value of the second pressure sensor 24 becomes a predetermined pressure value relative to the detection value of the first pressure sensor 16, thereby increasing the cooling efficiency.

[0072] (Opening degree of the first variable expansion valve 36) The control means 10 adjusts the temperature of the circulating water by changing the aperture of the first variable expansion valve 36. When the aperture of the first variable expansion valve 36 is increased, the amount of low-temperature CO2 refrigerant expanded by the first variable expansion valve 36 that flows into the first evaporator 38 increases, thereby increasing the amount of cooling of the circulating water. Conversely, when the aperture of the first variable expansion valve 36 is decreased, the amount of low-temperature CO2 refrigerant expanded by the first variable expansion valve 36 that flows into the first evaporator 38 decreases, thereby decreasing the amount of cooling of the circulating water.

[0073] (Opening degree of second variable expansion valve 40) Furthermore, the control means 10 adjusts the temperature of the processing water by changing the aperture of the second variable expansion valve 40. When the aperture of the second variable expansion valve 40 is increased, the amount of low-temperature CO2 refrigerant expanded by the second variable expansion valve 40 that flows into the second evaporator 42 increases, thereby increasing the amount of cooling of the processing water. Conversely, when the aperture of the second variable expansion valve 40 is decreased, the amount of low-temperature CO2 refrigerant expanded by the second variable expansion valve 40 that flows into the second evaporator 42 decreases, thereby decreasing the amount of cooling of the processing water.

[0074] (Rotational speed of compressor 14) Furthermore, the control means 10 adjusts the detection values of the first and second pressure sensors 16, 24 by increasing or decreasing the rotation speed of the compressor 14. When the rotation speed of the compressor 14 increases, the detection value of the first pressure sensor 16 decreases and the detection value of the second pressure sensor 24 increases. Conversely, when the rotation speed of the compressor 14 decreases, the detection value of the first pressure sensor 16 increases and the detection value of the second pressure sensor 24 decreases.

[0075] (cooling efficiency) Cooling efficiency is a measure of energy consumption efficiency and can be defined as cooling capacity divided by compression work (cooling efficiency = cooling capacity / compression work). Cooling capacity is the sum of the capacity of the CO2 refrigerant to cool the circulating water in the first evaporator 38 and the capacity of the CO2 refrigerant to cool the process water in the second evaporator 42. Compression work is the work performed by the compressor 14, that is, the power consumed by the motor 14b of the compressor 14.

[0076] The control means 10 of this embodiment determines the required cooling capacity based on the set temperature of the circulating water (first temperature or second temperature) and the set temperature of the processing water (third temperature or fourth temperature), and controls the pressure of the CO2 refrigerant to satisfy this cooling capacity by adjusting the opening of the first and second variable expansion valves 36, 40 and the rotation speed of the compressor 14. At this time, the control means 10 sets the rotation speed of the compressor 14 to the minimum required (i.e., minimizes the compression work) to increase cooling efficiency.

[0077] Next, the operation of the temperature control device 2 when increasing or decreasing the cooling amount of the circulating water and processing water (that is, when changing the set temperature of the circulating water and processing water) will be described.

[0078] (When increasing the amount of cooling for circulating water and processing water) First, the case where the cooling amount of the circulating water and the processing water is increased (the set temperature of the circulating water and the processing water is lowered) will be described. When increasing the cooling amount of the circulating water, the control means 10 increases the aperture of the first variable expansion valve 36. This increases the amount of low-temperature CO2 refrigerant expanded by the first variable expansion valve 36 flowing into the first evaporator 38, thereby increasing the cooling amount of the circulating water. Furthermore, when increasing the cooling amount of the processing water, the control means 10 increases the aperture of the second variable expansion valve 40. This increases the amount of low-temperature CO2 refrigerant expanded by the second variable expansion valve 40 flowing into the second evaporator 42, thereby increasing the cooling amount of the processing water.

[0079] However, when the flow rate of the CO2 refrigerant in the first and second evaporators 38 and 42 increases, the value detected by the first pressure sensor 16 may exceed the first pressure value, and the value detected by the second pressure sensor 24 may fall below the second pressure value. Therefore, the control means 10 appropriately increases the rotation speed of the compressor 14 in accordance with the amount of reduction in the set temperature of the circulating water and the process water. This allows the value detected by the first pressure sensor 16 to be maintained at the first pressure value, and the value detected by the second pressure sensor 24 to be maintained at the second pressure value. Therefore, in the temperature control device 2, even if the cooling rate of the circulating water and the process water is increased, the discharge pressure of the compressor 14 does not fluctuate significantly, thereby achieving highly efficient cooling control.

[0080] (When reducing the cooling rate of circulating water and processing water) Next, a case where the cooling amount of the circulating water and the processing water is reduced (a case where the set temperature of the circulating water and the processing water is increased) will be described. When reducing the cooling amount of the circulating water, the control means 10 reduces the opening of the first variable expansion valve 36. This reduces the amount of low-temperature CO refrigerant expanded by the first variable expansion valve 36 flowing into the first evaporator 38, thereby reducing the cooling amount of the circulating water. Furthermore, when reducing the cooling amount of the processing water, the control means 10 reduces the opening of the second variable expansion valve 40. This reduces the amount of low-temperature CO refrigerant expanded by the second variable expansion valve 40 flowing into the second evaporator 42, thereby reducing the cooling amount of the processing water.

[0081] However, when the flow rate of the CO2 refrigerant in the first and second evaporators 38 and 42 decreases, the detection value of the first pressure sensor 16 may fall below the first pressure value, and the detection value of the second pressure sensor 24 may exceed the second pressure value. Therefore, the control means 10 appropriately reduces the rotation speed of the compressor 14 according to the increase in the set temperature of the circulating water and the processing water.

[0082] In this case, even though the rotation speed of the compressor 14 has reached the minimum allowable rotation speed, there may be times when the detection value of the first pressure sensor 16 does not rise to the first pressure value and the detection value of the second pressure sensor 24 does not fall to the second pressure value. In such a case, the control means 10 gradually increases the opening of the variable bypass valve 76 from fully closed to allow a portion of the CO2 refrigerant flowing out of the compressor 14 to flow through the bypass path 74. As a result, the value of the first pressure sensor 16 can be increased to the first pressure value and the value of the second pressure sensor 24 can be decreased to the second pressure value without reducing the rotation speed of the compressor 14 to a speed lower than the minimum allowable rotation speed. Note that when the variable bypass valve 76 is opened, the rotation speed of the compressor 14 may be set to a speed higher than the minimum allowable rotation speed.

[0083] In this way, when there is a risk that the rotation speed of the compressor 14 will fall below the minimum allowable rotation speed, the control means 10 adjusts the opening of the variable bypass valve 76 to maintain the rotation speed of the compressor 14 at the minimum allowable rotation speed or to increase the rotation speed of the compressor 14. Therefore, in the temperature control device 2, even if the cooling rate of the circulating water and process water is reduced, the discharge pressure of the compressor 14 does not fluctuate significantly, making it possible to achieve highly efficient cooling control.

[0084] (When cooling circulating water and heating processing water) Next, a case where the circulating water is cooled and the processing water is heated will be described.

[0085] (setting value) In the temperature control device 2, when cooling the circulating water and heating the processing water, as in the case of cooling the circulating water and processing water, when an operation command is input by the operator to the control means 10, the values (set values) to be detected by each sensor are set according to the input operation command. Specifically, the set temperatures of the circulating water (first and second temperatures), the set temperatures of the processing water (third and fourth temperatures), and the set pressures of the CO2 refrigerant (first and second pressure values) are set. The set temperatures of the circulating water and processing water are temperatures input by the operator. Meanwhile, the set pressure of the CO2 refrigerant is determined by the control means 10 based on the set temperatures of the circulating water and processing water.

[0086] Once the set temperatures of the circulating water and processing water and the set pressure of the CO2 refrigerant have been set, the actual processing water temperature is compared with the set temperature to determine whether to cool or heat the processing water. If the actual processing water temperature is lower than the set temperature, the control means 10 heats the processing water. As described above, the circulating water is always cooled in the first evaporator 38 to remove heat from heat-generating components such as the spindle unit in the processing device 48.

[0087] When cooling the circulating water and heating the processing water, the control means 10 normally opens the variable valve 22, the variable heating control valve 58, and the first variable expansion valve 36, while closing the variable bypass valve 76, the second and third variable expansion valves 40, 70, and the first and second water control valves 64, 66. As a result, the CO refrigerant circulates through the first path 12, the second path 18, the heating path 52, the third path 28, the fourth path 30, and the sixth path 44, as shown by the thick solid lines in Figure 2. The circulating water also circulates through the circulating water path 6, and the processing water is supplied from the processing water source 50 to the processing device 48 via the processing water path 8.

[0088] When cooling the circulating water and heating the processing water, the control means 10 fully closes the second variable expansion valve 40 and adjusts the aperture of the variable heating control valve 58 so that the processing water is heated to a predetermined temperature. When adjusting the aperture of the variable heating control valve 58, the control means 10 also adjusts the aperture of the variable valve 22 so that the difference between the detection values of the second pressure sensor 24 and the third pressure sensor 54 becomes a predetermined value, thereby keeping the amount of heating of the processing water constant.

[0089] (CO2 refrigerant flow) The flow of CO2 refrigerant and the function of each device will be described below. When cooling circulating water and heating processing water, CO2 refrigerant flows into compressor 14 from first path 12, is compressed by compressor 14, and flows into second path 18. The high-temperature, high-pressure CO2 refrigerant that flows into second path 18 branches at first connecting portion 52a, flows into variable valve 22, and flows into refrigerant passage 56a of second condenser 56 via heating path 52. In second condenser 56, heat exchange occurs between the CO2 refrigerant in refrigerant passage 56a and the processing water in processing water passage 56b. This transfers heat from the CO2 refrigerant to the processing water. In other words, the processing water is heated by the CO2 refrigerant.

[0090] The CO2 refrigerant that has passed through the variable valve 22 and the CO2 refrigerant that has passed through the second condenser 56 and the variable heating control valve 58 join at the second connecting portion 52b. The joined CO2 refrigerant passes through the refrigerant passage 20a of the first condenser 20 and then flows into the first passage 26a of the internal heat exchanger 26 via the third passage 28. The CO2 refrigerant that has flowed into the first passage 26a imparts heat to the CO2 refrigerant passing through the second passage 26b, and then flows into the first variable expansion valve 36 via the fourth passage 30. The CO2 refrigerant that has flowed into the first variable expansion valve 36 is expanded in the first variable expansion valve 36, resulting in a decrease in pressure and temperature.

[0091] The CO2 refrigerant that has passed through the first variable expansion valve 36 flows into the refrigerant passage 38a of the first evaporator 38. In the first evaporator 38, heat exchange occurs between the CO2 refrigerant in the refrigerant passage 38a and the circulating water in the circulating water passage 38b. As a result, the CO2 refrigerant absorbs heat from the circulating water and vaporizes, while the circulating water is cooled by the CO2 refrigerant. However, some of the CO2 refrigerant that has passed through the first evaporator 38 may remain liquid.

[0092] The CO2 refrigerant that has passed through the first evaporator 38 flows into the second passage 26b of the internal heat exchanger 26 via the sixth passage 44. The CO2 refrigerant that has flowed into the second passage 26b absorbs heat from the CO2 refrigerant that has passed through the first passage 26a. Therefore, even if liquid remains in the CO2 refrigerant that has passed through the first evaporator 38, all of the liquid in the CO2 refrigerant becomes gas in the second passage 26b of the internal heat exchanger 26. Then, the CO2 refrigerant that has passed through the second passage 26b of the internal heat exchanger 26 passes through the first passage 12 and is drawn into the compressor 14.

[0093] As described above, in this embodiment, the CO2 refrigerant circulates through the path indicated by the bold line in FIG. 2, thereby cooling the circulating water in the first evaporator 38 and heating the processing water in the second condenser 56. Furthermore, in the internal heat exchanger 26 of this embodiment, the CO2 refrigerant that has passed through the first evaporator 38 absorbs heat from the CO2 refrigerant that has passed through the first condenser 20. As a result, the liquid CO2 refrigerant remaining in the CO2 refrigerant that has passed through the first evaporator 38 disappears. As a result, all of the CO2 refrigerant drawn into the compressor 14 becomes gas, reducing the load on the compressor 14. Therefore, this embodiment solves the problem of shortening the lifespan of the compressor 14 by compressing liquid CO2 refrigerant.

[0094] (Improved cooling efficiency and coefficient of performance) The control means 10 of this embodiment adjusts the opening of the first variable expansion valve 36 so that the temperature of the circulating water becomes a predetermined temperature, adjusts the opening of the variable heating control valve 58 and the variable valve 22 so that the temperature of the processing water becomes a predetermined temperature, and also adjusts the rotation speed of the compressor 14 so that the detection value of the second pressure sensor 24 becomes a predetermined pressure value relative to the detection value of the first pressure sensor 16, thereby improving cooling efficiency and performance efficiency.

[0095] (Opening degree of the first variable expansion valve 36) The control means 10 adjusts the temperature of the circulating water by changing the aperture of the first variable expansion valve 36. When the aperture of the first variable expansion valve 36 is increased, the amount of low-temperature CO2 refrigerant expanded by the first variable expansion valve 36 that flows into the first evaporator 38 increases, thereby increasing the amount of cooling of the circulating water. Conversely, when the aperture of the first variable expansion valve 36 is decreased, the amount of low-temperature CO2 refrigerant expanded by the first variable expansion valve 36 that flows into the first evaporator 38 decreases, thereby decreasing the amount of cooling of the circulating water.

[0096] (Opening degree of variable heating control valve 58 and variable valve 22) The control means 10 adjusts the temperature of the processing water by changing the apertures of the variable heating control valve 58 and the variable valve 22. Increasing the aperture of the variable heating control valve 58 and decreasing the aperture of the variable valve 22 increases the flow rate of high-temperature CO2 refrigerant passing through the refrigerant passage 56a of the second condenser 56, thereby increasing the amount of heat being applied to the processing water. Conversely, decreasing the aperture of the variable heating control valve 58 and increasing the aperture of the variable valve 22 decreases the flow rate of high-temperature CO2 refrigerant passing through the refrigerant passage 56a of the second condenser 56, thereby decreasing the amount of heat being applied to the processing water. Note that the amount of heat applied to the processing water can be increased or decreased in addition to adjusting the apertures of the variable heating control valve 58 and the variable valve 22, as will be described later.

[0097] (Rotational speed of compressor 14) Furthermore, the control means 10 adjusts the detection values of the first and second pressure sensors 16, 24 by increasing or decreasing the rotation speed of the compressor 14. When the rotation speed of the compressor 14 increases, the detection value of the first pressure sensor 16 decreases and the detection value of the second pressure sensor 24 increases. Conversely, when the rotation speed of the compressor 14 decreases, the detection value of the first pressure sensor 16 increases and the detection value of the second pressure sensor 24 decreases.

[0098] (Cooling efficiency / coefficient of performance) As described above, cooling efficiency is a measure of energy consumption efficiency and can be defined as the cooling capacity divided by the compression work (cooling efficiency = cooling capacity / compression work). When cooling circulating water and heating processing water, the cooling capacity is the capacity of the CO2 refrigerant to cool the circulating water in the first evaporator 38. Furthermore, the coefficient of performance is a measure of energy consumption efficiency and can be defined as the heating capacity divided by the compression work (cooling efficiency = heating capacity / compression work). The heating capacity is the capacity of the CO2 refrigerant to heat the processing water in the second condenser 56. As described above, the compression work is the work performed by the compressor 14 (the power consumed by the motor 14b of the compressor 14).

[0099] The control means 10 of this embodiment determines the required cooling capacity based on the set temperature of the circulating water (first temperature or second temperature), and determines the required heating capacity based on the set temperature of the processing water (third temperature or fourth temperature).The control means 10 then adjusts the openings of the first and second variable expansion valves 36, 40, the variable valve 22, and the variable heating control valve 58, as well as the rotation speed of the compressor 14, to control the pressure of the CO2 refrigerant so as to satisfy the determined cooling capacity and heating capacity.At this time, the control means 10 keeps the rotation speed of the compressor 14 at the minimum required speed (i.e., minimizes the compression work) to increase the cooling efficiency and coefficient of performance.

[0100] Next, the operation of the temperature control device 2 when increasing or decreasing the heating amount of the processing water (i.e., when changing the set temperature of the processing water) will be described. Note that, since the increase or decrease in the cooling amount of the circulating water has been described above, the case of increasing or decreasing the heating amount of the processing water will be described here.

[0101] (When increasing the amount of heat in the processing water) First, the case where the amount of heating of the processing water is increased (the set temperature of the processing water is increased) will be described. When the amount of heating of the processing water is increased, the control means 10 increases the opening of the variable heating control valve 58 and decreases the opening of the variable valve 22. This increases the flow rate of high-temperature CO refrigerant passing through the refrigerant passage 56a of the second condenser 56, thereby increasing the amount of heating of the processing water.

[0102] Furthermore, when increasing the amount of heat to be applied to the processing water, the control means 10 can open the third variable expansion valve 70 and the second water control valve 66 to perform heat exchange in the third evaporator 68. When the third variable expansion valve 70 opens, low-temperature CO refrigerant expanded by the third variable expansion valve 70 flows into the refrigerant passage 68a of the third evaporator 68. When the second water control valve 66 opens, industrial water flows into the industrial water passage 68b of the third evaporator 68. As a result, in the third evaporator 68, heat exchange occurs between the CO refrigerant in the refrigerant passage 68a and the industrial water in the industrial water passage 68b, and heat is imparted from the industrial water to the CO refrigerant. The CO refrigerant that has received heat from the industrial water in the third evaporator 68 then passes through the second passage 26b of the internal heat exchanger 26 and the compressor 14, and imparts heat to the processing water in the second condenser 56. As a result, the amount of heat to be applied to the processing water is increased compared to when heat exchange is not performed in the third evaporator 68. In this way, the control means 10 can increase the amount of heat to be applied to the processing water by opening the third variable expansion valve 70 and the second water control valve 66 and performing heat exchange in the third evaporator 68.

[0103] When heat exchange is performed in the third evaporator 68, the control means 10 improves the heat exchange rate in the third evaporator 68. If the temperature difference between the temperature of the industrial water flowing into the third evaporator 68 (the value detected by the fifth temperature sensor 86) and the temperature of the industrial water flowing out of the third evaporator 68 (the value detected by the sixth temperature sensor 88) is too large, the heat exchange rate in the third evaporator 68 will deteriorate. Therefore, when the temperature difference is greater than a predetermined value, the control means 10 adjusts (increases) the opening of the second water control valve 66 to provide heat to the CO2 refrigerant in order to compensate for the insufficient flow rate of the industrial water and keep the temperature difference within the predetermined value, thereby improving the heat exchange rate of the third evaporator 68.

[0104] When the control means 10 performs heat exchange in the third evaporator 68 to increase the heating amount of the processing water, it can also open the first water control valve 64 to send industrial water to the first condenser 20. When the first water control valve 64 opens, industrial water flows into the industrial water passage 20b of the first condenser 20. In this way, in the first condenser 20, heat exchange occurs between the CO2 refrigerant in the refrigerant passage 20a, which has been compressed by the compressor 14 to a high temperature and high pressure, and the industrial water in the industrial water passage 20b, and the industrial water absorbs heat from the high-temperature CO2 refrigerant. The industrial water that absorbed heat from the CO2 refrigerant is sent to the third evaporator 68.

[0105] In the third evaporator 68, heat is exchanged between the CO2 refrigerant in the refrigerant passage 68a, which has been expanded by the third variable expansion valve 70 to a low temperature and low pressure, and the industrial water in the industrial water passage 68b, so that the industrial water provides heat to the low-temperature CO2 refrigerant. The CO2 refrigerant that has received heat from the industrial water in the third evaporator 68 then passes through the second passage 26b of the internal heat exchanger 26 and the compressor 14, and then provides further heat to the processing water in the second condenser 56. As a result, the amount of heat applied to the processing water is increased compared to when industrial water is not fed to the first condenser 20.

[0106] When industrial water is fed to the first condenser 20 to further heat the processing water in the second condenser 56, the control means 10 adjusts the aperture of the second water control valve 66 to prevent a decrease in the efficiency of the third evaporator 68. If the temperature difference between the temperature of the industrial water flowing into the third evaporator 68 and the temperature of the industrial water flowing out of the third evaporator 68 is too small, the heat exchange rate in the third evaporator 68 will decrease. Therefore, the control means 10 adjusts the aperture of the second water control valve 66 so that the temperature difference becomes a predetermined value, thereby preventing a decrease in the efficiency of the third evaporator 68.

[0107] (When reducing the amount of heat in the processing water) Finally, the case where the amount of heat applied to the processing water is reduced (the set temperature of the processing water is reduced) will be described. When the amount of heat applied to the processing water is reduced, the control means 10 reduces the opening of the variable heating control valve 58 and increases the opening of the variable valve 22. This reduces the flow rate of the high-temperature CO refrigerant passing through the refrigerant passage 56a of the second condenser 56, thereby reducing the amount of heat applied to the processing water.

[0108] As described above, in the internal heat exchanger 26 of the temperature control device 2, the CO refrigerant that has passed through the first and second evaporators 38, 42 absorbs heat from the CO refrigerant that has passed through the first condenser 20. Therefore, any liquid CO refrigerant remaining in the CO refrigerant that has passed through the first and second evaporators 38, 42 disappears. As a result, all of the CO refrigerant drawn into the compressor 14 becomes gas, reducing the load on the compressor 14. Therefore, this embodiment eliminates the problem of shortening the life of the compressor 14 by compressing liquid CO refrigerant. Furthermore, this embodiment determines the cooling capacity and heating capacity based on the set temperatures of the circulating water and the process water. The openings of the first and second variable expansion valves 36, 40 and the variable valve 22 are controlled to satisfy these cooling and heating capacities, and the rotation speed of the compressor 14 is adjusted to the minimum required rotation speed, thereby improving the cooling efficiency and coefficient of performance. [Explanation of symbols]

[0109] 2: Temperature control device 4: Basic Route 6: Circulating water route 8: Processing water route 10: Control means 12: First Route 14: Compressor 16: First pressure sensor 18: Second Path 20: First condenser 22: Variable valve 24: Second pressure sensor 26: Internal heat exchanger 28: The Third Path 30: The Fourth Path 32: The fifth route 34: Branch 36: First variable expansion valve 38: First evaporator 40: Second variable expansion valve 42: Second evaporator 44: The Sixth Path 52: Heating path 54: Third pressure sensor 56: Second condenser 58: Variable heating control valve 60: Industrial water route 62: Industrial water supply source 64: First water control valve 66: Second water control valve 68: Third evaporator 70: Third variable expansion valve 74: Bypass route 76: Variable bypass valve

Claims

1. A temperature control device that controls the temperature of circulating water and the temperature of processing water, CO ２ A CO ２ a compressor that compresses a refrigerant; CO2 is disposed in the first path and sent to the compressor. ２ a first pressure sensor for detecting the pressure of the refrigerant; CO compressed by the compressor ２ a second path for delivering the refrigerant; a first condenser disposed in the second path; a variable valve disposed between the compressor and the first condenser; A CO condenser is disposed between the variable valve and the first condenser. ２ a second pressure sensor for detecting the pressure of the refrigerant; CO from the first condenser ２ a third passage having an internal heat exchanger into which the refrigerant is pumped; a branching portion that branches the third path into a fourth path and a fifth path; a first variable expansion valve and a first evaporator disposed in the fourth path; a second variable expansion valve and a second evaporator disposed in the fifth passage; The fourth path and the fifth path join together to supply CO to the internal heat exchanger. ２ Refrigerant is pumped in and CO ２ Heat is given to the refrigerant to turn it into liquid CO ２ a sixth path through which the refrigerant disappears; In the basic path, CO is supplied from the internal heat exchanger to the compressor via the first path. ２ The refrigerant is pumped in moreover, a circulating water path communicating with the first evaporator to control the temperature of the circulating water; a processing water passage communicating with the second evaporator to control the temperature of the processing water; and a control means.

2. a heating path is provided that is connected to the second path from the compressor to the variable valve and that is connected to the second path from the variable valve to the first condenser, the heating path including a third pressure sensor, a second condenser, and a variable heating control valve; The processing water path is connected to the second condenser and ２ 2. The temperature control device of claim 1, wherein the refrigerant provides heat to the processing water.

3. The first condenser contains CO ２ an industrial water passage through which industrial water flows to remove heat from the refrigerant; the industrial water passage includes a first water control valve for supplying industrial water to the first condenser and an outlet for discharging the industrial water, and a second water control valve between the first condenser and the outlet; a third evaporator is disposed between the second water control valve and the outlet; the third evaporator is in communication with the branch portion via a third variable expansion valve and is in communication with the sixth path; CO to which heat is given from industrial water in the third evaporator ２ 3. The temperature control system of claim 2, wherein a refrigerant provides heat to the process water in said second condenser.

4. 2. The temperature control device according to claim 1, wherein a bypass path is provided connecting the second path between the compressor and the variable valve to the sixth path before the internal heat exchanger, the bypass path including a variable bypass valve.

5. 5. The temperature control device according to claim 4, wherein when there is a risk that the rotation speed of the compressor will fall below a minimum allowable rotation speed, the control means adjusts the opening of the variable bypass valve to maintain the rotation speed of the compressor at the minimum allowable rotation speed or to increase the rotation speed of the compressor.

6. When the temperature difference between the temperature of the industrial water flowing into the third evaporator and the temperature of the industrial water flowing out of the third evaporator is greater than a predetermined value, the control means adjusts the opening of the second water control valve so that the temperature difference is within the predetermined value to compensate for the insufficiency of the flow rate of the industrial water, thereby reducing CO ２ 4. A temperature control device according to claim 3, wherein heat is imparted to the refrigerant to improve the heat exchange rate of said third evaporator.

7. The temperature control device of claim 1, wherein the control means adjusts the opening of the first variable expansion valve so that the temperature of the circulating water becomes a predetermined temperature, adjusts the opening of the second variable expansion valve so that the temperature of the processing water becomes a predetermined temperature, and also adjusts the rotation speed of the compressor so that the detection value of the second pressure sensor becomes a predetermined pressure value relative to the detection value of the first pressure sensor.

8. 3. The temperature control device according to claim 2, wherein said control means fully closes said second variable expansion valve and adjusts the opening of said variable heating control valve so that the processing water is heated to a predetermined temperature.

9. 9. The temperature control device according to claim 8, wherein the control means adjusts the opening of the variable heating control valve so that the difference between the detection value of the second pressure sensor and the detection value of the third pressure sensor becomes a predetermined value, thereby maintaining a constant amount of heating of the processing water.

10. The control means opens the first water control valve to send industrial water to the first condenser to reduce CO ２ The industrial water that has absorbed heat from the refrigerant is sent to the third evaporator to ２ 4. The temperature control system of claim 3, wherein heat is applied to the refrigerant to provide additional heat to the process water in said second condenser.

11. 11. The temperature control device according to claim 10, wherein the control means adjusts the opening of the second water control valve so that the difference between the temperature of the industrial water flowing into the third evaporator and the temperature of the industrial water flowing out of the third evaporator becomes a predetermined value, thereby preventing a decrease in the efficiency of the third evaporator.

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