Heating mechanism

Abstract

To provide a heating mechanism capable of improving a coefficient of performance.SOLUTION: Control means 4 of a heating mechanism 2 controls an opening of a variable expansion valve 32, a rotation speed of a compressor 6, and an opening of a water control valve 20 according to a path defined by a setting pressure value and a setting temperature surrounding a critical point identified by a critical temperature of 31.1°C and a critical pressure of 7.38 MPa of a CO2 refrigerant, so that a value of a first temperature sensor 38 or a second temperature sensor 40 becomes the setting temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heating mechanism for heating a processing liquid used in a processing device. [Background technology]

[0002] A wafer has a number of devices such as ICs and LSIs formed on its front surface along planned dividing lines, and the back surface is ground by a grinding machine to form it to a specified thickness. The wafer is then divided into individual device chips using a dicing machine and laser processing machine, and each of the divided device chips 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 thermally, high-precision grinding or cutting cannot be performed. For this reason, a temperature control device is used to control the temperature of the spindle unit to a constant value (see, for example, Patent Document 1). The temperature control device described in Patent Document 1 is a type of device that uses CO2 as a refrigerant, and can achieve high cooling efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-40396 A Summary of the Invention [Problem to be solved by the invention]

[0005] When grinding or dicing equipment is used in cold regions, the temperature of the processing liquid may drop below the specified temperature. In such cases, it is necessary to use an electric heater to heat the processing liquid to the specified temperature. However, the heating capacity of an electric heater corresponds to the power consumption, and there is a problem that the coefficient of performance (heating capacity / power consumption) is small at 1.

[0006] An object of the present invention is to provide a heating mechanism capable of increasing the coefficient of performance. [Means for solving the problem]

[0007] According to the present invention, there is provided the following heating mechanism that solves the above problems. "A heating mechanism for heating a processing liquid used in a processing device, A control means; A compressor for compressing the CO2 refrigerant; A water-cooled gas cooler that removes heat from the CO2 refrigerant compressed by the compressor and provides heat to a processing liquid used in the processing device; The CO2 refrigerant that has lost heat is sent to an internal heat exchanger. an evaporator that vaporizes the CO2 refrigerant sent from the internal heat exchanger to generate heat of vaporization; a first passage connecting the compressor and the water-cooled gas cooler; a second passage connecting the water-cooled gas cooler and the evaporator; a third passage connecting the evaporator and the compressor; A fourth passage having a water control valve through which industrial water or wastewater used in a processing device is introduced into the evaporator to give heat to the CO2 refrigerant; a bypass passage connected to the first passage by a first connecting portion connected to the first passage and a second connecting portion connected to the second passage, the bypass passage including a variable bypass valve; the internal heat exchanger is disposed across the second path and the third path so that the CO2 refrigerant discharged from the evaporator removes heat from the CO2 refrigerant discharged from the water-cooled gas cooler; a variable expansion valve for adjusting a flow rate of the CO refrigerant from which heat has been removed is disposed in the second passage between the internal heat exchanger and the second connecting portion; a first pressure sensor for measuring a pressure of a CO2 refrigerant is disposed in either the second path or the third path between the variable expansion valve and the compressor; a second pressure sensor for measuring a pressure of the CO refrigerant compressed by the compressor is disposed in either the first path or the second path between the compressor and the variable expansion valve; A first temperature sensor for measuring a temperature of a processing liquid used in a processing device flowing out from the water-cooled gas cooler; A second temperature sensor that measures the temperature of the processing liquid flowing into the water-cooled gas cooler; a third temperature sensor for measuring the temperature of the industrial water or wastewater used in a processing device flowing out from the evaporator; a fourth temperature sensor for measuring the temperature of industrial water or wastewater used in a processing device flowing into the evaporator; a fifth temperature sensor for measuring a temperature of the CO2 refrigerant discharged from the compressor; and a sixth temperature sensor for measuring the temperature of the CO2 refrigerant discharged from the water-cooled gas cooler; a seventh temperature sensor disposed in the third path for measuring a temperature of the CO refrigerant discharged from the internal heat exchanger to the compressor; the control means includes a setting unit that sets at least a first pressure value to be detected by the first pressure sensor, a second pressure value to be detected by the second pressure sensor, a first temperature to be detected by the first temperature sensor or a second temperature to be detected by the second temperature sensor, a fifth temperature to be detected by the fifth temperature sensor, and a seventh temperature to be detected by the seventh temperature sensor; There is provided a heating mechanism which controls the opening of the variable expansion valve, the rotation speed of the compressor, and the opening of the water control valve according to a path defined by the set pressure value and temperature surrounding a critical point identified by a critical temperature of 31.1°C and a critical pressure of 7.38 MPa for the CO2 refrigerant, so that the value of the first temperature sensor or the second temperature sensor becomes the set temperature.

[0008] Preferably, when the control means reduces the amount of heat of the processing-contributing liquid used in the processing apparatus, it reduces the rotation speed of the compressor to reduce the flow rate of the CO2 refrigerant flowing through the water-cooled gas cooler, and at that time, increases the opening of the variable bypass valve of the bypass path to reduce the flow rate of the CO2 refrigerant flowing through the water-cooled gas cooler so that the rotation speed of the compressor does not fall below a lower limit value.

[0009] When the control means increases the amount of heating of the processing-contributing liquid used in the processing equipment, it is desirable that the control means increases the opening of the variable expansion valve and the rotation speed of the compressor to increase the flow rate of the CO2 refrigerant flowing through the evaporator, and accordingly vaporizes the liquid CO2 remaining in the CO2 refrigerant discharged from the evaporator in the internal heat exchanger, thereby reducing the burden on the compressor.

[0010] It is preferable that the control means provides heat to the CO2 refrigerant by adjusting the opening of the water control valve so that the temperature difference between the temperature of the industrial water or the wastewater used in the processing equipment detected by the third temperature sensor and the temperature of the industrial water or the wastewater used in the processing equipment detected by the fourth temperature sensor becomes a predetermined value.

[0011] It is preferable that the control means adjusts the pressure to the set pressure value by reducing the opening of the variable expansion valve to increase the value of the second pressure sensor, and by increasing the opening of the variable expansion valve to decrease the value of the second pressure sensor, thereby controlling the coefficient of performance (heating capacity / compression work).

[0012] The outlet of the compressor is point A. The outlet of the water-cooled gas cooler is point B. The outlet of the second passage in the internal heat exchanger is at point C; The outlet of the variable expansion valve is at point D. The outlet of the evaporator is point E. The outlet of the third passage in the internal heat exchanger is at point F; The temperature at point A is TA, the pressure is PA, and the enthalpy is EA. The temperature at point B is TB, the pressure is PB, and the enthalpy is EB. The temperature at point C is TC, the pressure is PC, and the enthalpy is EC. The temperature at point D is TD, the pressure is PD, and the enthalpy is ED. The temperature at point E is TE, the pressure is PE, and the enthalpy is EE. If the temperature at point F is TF, the pressure is PF, and the enthalpy is EF, The CO2 refrigerant fed from point F to the compressor is compressed by the compressor and reaches point A where the critical point is exceeded. The temperature changes from TF to TA, the pressure changes from PF to PA, and the enthalpy changes from EF to EA. The CO2 refrigerant sent from point A to the water-cooled gas cooler has heat removed by the water-cooled gas cooler and reaches point B, where its temperature changes from TA to TB, its pressure does not change (PA=PB), and its enthalpy changes from EA to EB. The temperature difference between TA and TB and the enthalpy difference between EA and EB are used by the water-cooled gas cooler to heat the processing liquid, and the temperature TB falls below the critical temperature, and the CO2 refrigerant approaches a liquid state by entering a subcritical state. The CO2 refrigerant sent from point B to the internal heat exchanger has heat removed by the CO2 refrigerant sent from the evaporator and reaches point C, where the temperature changes from TB to TC, the pressure does not change (PB=PC), the enthalpy changes from EB to EC, the temperature TC becomes further below the critical temperature, and the CO2 refrigerant becomes even closer to a liquid state. The CO2 refrigerant fed from point C to the variable expansion valve is decompressed by the variable expansion valve and reaches point D, where the temperature changes from TC to TD, the pressure changes from PC to PD, the enthalpy does not change (EC=ED), and the CO2 refrigerant reaches the saturated liquid line. The CO2 refrigerant sent to the evaporator from point D absorbs energy from industrial water or wastewater used in processing equipment by the evaporator and reaches point E, where the temperature and pressure do not change (TD=TE, PD=PE), the enthalpy changes from ED to EE, and point E is inside the saturated vapor line and the CO2 refrigerant becomes a gas containing liquid. The CO2 refrigerant sent to the internal heat exchanger from point E absorbs heat from the CO2 refrigerant sent to the internal heat exchanger from point B, turns into gas, and reaches point F, where the temperature changes from TE to TF, the pressure does not change (PE=PF), and the enthalpy changes from EE to EF, and the point reaches point A. The control means The temperature, pressure, and enthalpy can be controlled so that the coefficient of performance (heating capacity / compression work) = (EA-EB) / (EA-EF) is maximized.

[0013] The temperature TA at point A is detected by the fifth temperature sensor; The temperature TB at the point B is detected by the sixth temperature sensor; The temperature TF at the point F is detected by the seventh temperature sensor; The pressure PA at point A is detected by the second pressure sensor; The pressure PB at point B is detected by the second pressure sensor; The pressure PF at point F is detected by the first pressure sensor; The enthalpy EA at point A is detected based on the pH diagram, The enthalpy EB at point B is detected based on the pH diagram, The enthalpy EF at point F is detected based on a pH diagram; The control means Coefficient of performance (heating capacity / compression work) = (EA-EB) / (EA-EF) It is advantageous to increase the heating capacity and reduce the compression work by using the above formula to improve the coefficient of performance. Effect of the Invention

[0014] The heating mechanism of the present invention comprises: A control means; A compressor for compressing the CO2 refrigerant; A water-cooled gas cooler that removes heat from the CO2 refrigerant compressed by the compressor and provides heat to a processing liquid used in the processing device; The CO2 refrigerant that has lost heat is sent to an internal heat exchanger. an evaporator that vaporizes the CO2 refrigerant sent from the internal heat exchanger to generate heat of vaporization; a first passage connecting the compressor and the water-cooled gas cooler; a second passage connecting the water-cooled gas cooler and the evaporator; a third passage connecting the evaporator and the compressor; A fourth passage having a water control valve through which industrial water or wastewater used in a processing device is introduced into the evaporator to give heat to the CO2 refrigerant; a bypass passage connected to the first passage by a first connecting portion connected to the first passage and a second connecting portion connected to the second passage, the bypass passage including a variable bypass valve; the internal heat exchanger is disposed across the second path and the third path so that the CO2 refrigerant discharged from the evaporator removes heat from the CO2 refrigerant discharged from the water-cooled gas cooler; a variable expansion valve for adjusting a flow rate of the CO refrigerant from which heat has been removed is disposed in the second passage between the internal heat exchanger and the second connecting portion; a first pressure sensor for measuring a pressure of a CO2 refrigerant is disposed in either the second path or the third path between the variable expansion valve and the compressor; a second pressure sensor for measuring a pressure of the CO refrigerant compressed by the compressor is disposed in either the first path or the second path between the compressor and the variable expansion valve; A first temperature sensor for measuring a temperature of a processing liquid used in a processing device flowing out from the water-cooled gas cooler; A second temperature sensor that measures the temperature of the processing liquid flowing into the water-cooled gas cooler; a third temperature sensor for measuring the temperature of the industrial water or wastewater used in a processing device flowing out from the evaporator; a fourth temperature sensor for measuring the temperature of industrial water or wastewater used in a processing device flowing into the evaporator; a fifth temperature sensor for measuring a temperature of the CO2 refrigerant discharged from the compressor; and a sixth temperature sensor for measuring the temperature of the CO2 refrigerant discharged from the water-cooled gas cooler; a seventh temperature sensor disposed in the third path for measuring a temperature of the CO refrigerant discharged from the internal heat exchanger to the compressor; the control means includes a setting unit that sets at least a first pressure value to be detected by the first pressure sensor, a second pressure value to be detected by the second pressure sensor, a first temperature to be detected by the first temperature sensor or a second temperature to be detected by the second temperature sensor, a fifth temperature to be detected by the fifth temperature sensor, and a seventh temperature to be detected by the seventh temperature sensor; The opening of the variable expansion valve, the rotation speed of the compressor, and the opening of the water control valve are controlled according to a path defined by the set pressure value and temperature surrounding the critical point identified by the critical temperature of 31.1°C and the critical pressure of 7.38 MPa of CO2 refrigerant so that the value of the first temperature sensor or the second temperature sensor becomes the set temperature, thereby improving the coefficient of performance. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a circuit diagram of a heating mechanism according to the present invention. [Diagram 2] CO2 pH diagram. [Diagram 3] FIG. 2 is a schematic diagram showing an example of the arrangement of the heating mechanism shown in FIG. 1. [Figure 4] 4 is a graph showing an example of compressor speed upon restarting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, preferred embodiments of the heating mechanism according to the present invention will be described with reference to the drawings.

[0017] (Heating mechanism 2) 1 shows a heating mechanism 2 for heating a processing liquid used in a processing device with a CO2 refrigerant. The heating mechanism 2 includes a control means 4, a compressor 6, a water-cooled gas cooler 8, an internal heat exchanger 10, and an evaporator 12.

[0018] (Control Means 4) The control means 4 is composed of a computer having a processor and a memory. The control means 4 in this embodiment includes a setting unit 4a and a control unit 4b. The setting unit 4a sets the pressure and temperature of the CO2 refrigerant based on an instruction input by an operator (for example, the temperature of the processing-contributing liquid used in the processing device). The control unit 4b controls the opening degree of the variable expansion valve 32, the rotation speed of the compressor 6, the opening degree of the water control valve 20, etc. so that the actual temperature of the processing-contributing liquid becomes the set temperature (the temperature input by the operator). The control contents by the control unit 4b will be explained in detail later.

[0019] (Compressor 6) The compressor 6 compresses the CO2 refrigerant circulating through the heating mechanism 2. As shown in FIG. 1, the motor 6a that drives the compressor 6 is provided with an inverter 6b. The inverter 6b changes the frequency of the power supplied to the motor 6a within a predetermined range (for example, 20 Hz to 120 Hz). This changes the rotation speed of the motor 6a and changes the rotation speed of the compressor 6 within the range of the allowable rotation speed (between a lower limit and an upper limit). The inverter 6b is electrically connected to the control means 4 and is controlled by the control unit 4b of the control means 4.

[0020] (Water-cooled gas cooler 8) The water-cooled gas cooler 8 removes heat from the CO2 refrigerant carrying the heat of compression compressed by the compressor 6, and provides heat to the processing-contributing liquid used in the processing device. As shown in Fig. 3, the water-cooled gas cooler 8 is provided with a refrigerant passage 8a through which the CO2 refrigerant flows, and a processing-contributing liquid passage 8b through which the processing-contributing liquid flows. In the water-cooled gas cooler 8, heat is exchanged between the CO2 refrigerant in the refrigerant passage 8a and the processing-contributing liquid in the processing-contributing liquid passage 8b, so that the heat of the CO2 refrigerant is provided to the processing-contributing liquid.

[0021] (internal heat exchanger 10) The CO2 refrigerant from which heat has been removed in the water-cooled gas cooler 8 is sent to the internal heat exchanger 10. As shown in FIG. 3, the internal heat exchanger 10 is formed with a first passage 10a through which the CO2 refrigerant from which heat has been removed in the water-cooled gas cooler 8 passes, and a second passage 10b through which the CO2 refrigerant passes after passing through the evaporator 12. In the internal heat exchanger 10, heat exchange is performed between the CO2 refrigerant in the first passage 10a and the CO2 refrigerant in the second passage 10b. As a result, the CO2 refrigerant in the second passage 10b sent out from the evaporator 12 removes heat from the CO2 refrigerant in the first passage 10a sent out from the water-cooled gas cooler 8.

[0022] (Evaporator 12) The evaporator 12 vaporizes the CO2 refrigerant sent from the internal heat exchanger 10 to generate heat of vaporization. As shown in Fig. 3, the evaporator 12 is provided with a refrigerant passage 12a through which the CO2 refrigerant flows and a water passage 12b through which industrial water or wastewater used in a processing device flows. The evaporator 12 provides the heat of the industrial water or wastewater to the CO2 refrigerant by exchanging heat between the CO2 refrigerant in the refrigerant passage 12a and the industrial water or wastewater in the water passage 12b.

[0023] (First to fourth routes 14, 16, 18, 22, bypass route 30) Continuing the explanation with reference to FIG. 1, the heating mechanism 2 further includes a first path 14 connecting the compressor 6 and the water-cooled gas cooler 8, a second path 16 connecting the water-cooled gas cooler 8 and the evaporator 12, a third path 18 connecting the evaporator 12 and the compressor 6, a fourth path 22 equipped with a water control valve 20 through which industrial water (or wastewater used in a processing device may be used) is introduced to the evaporator 12 and heats the CO2 refrigerant, and a bypass path 30 connected by a first connecting part 24 connected to the first path 14 and a second connecting part 26 connected to the second path 16 and equipped with a variable bypass valve 28. In the second path 16, a variable expansion valve 32 for adjusting the flow rate of the CO2 refrigerant from which heat has been removed is disposed between the internal heat exchanger 10 and the second connecting part 26. In addition, the internal heat exchanger 10 is disposed across the second path 16 and the third path 18.

[0024] (Water control valve 20, variable bypass valve 28, variable expansion valve 32) 1, the water control valve 20, the variable bypass valve 28, and the variable expansion valve 32 are provided with motors 20a, 28a, and 32a for adjusting the opening degree, respectively. The motors 20a, 28a, and 32a are all electrically connected to the control means 4. The opening degrees of the water control valve 20, the variable bypass valve 28, and the variable expansion valve 32 are adjusted by the motors 20a, 28a, and 32a, respectively, based on instructions from the control unit 4b of the control means 4.

[0025] The CO2 refrigerant in the heating mechanism 2 passes through the first to third paths 14, 16, and 18 in order, and circulates through the compressor 6, the water-cooled gas cooler 8, the internal heat exchanger 10, the evaporator 12, and the internal heat exchanger 10 in that order. That is, in this embodiment, the CO2 refrigerant sent out from the compressor 6 passes through the internal heat exchanger 10 twice in principle before returning to the compressor 6 again. Specifically, the CO2 refrigerant that leaves the water-cooled gas cooler 8 passes through the internal heat exchanger 10, then passes through the evaporator 12, and then passes through the internal heat exchanger 10 again.

[0026] However, when the variable bypass valve 28 is opened, a portion of the CO2 refrigerant compressed by the compressor 6 is sent to the evaporator 12 through the bypass path 30 without passing through the water-cooled gas cooler 8 and the internal heat exchanger 10.

[0027] (Pressure Sensor) The heating mechanism 2 is provided with first and second pressure sensors 34, 36 as sensors for measuring the pressure of the CO2 refrigerant. The values ​​measured by the first and second pressure sensors 34, 36 are sent to the control means 4.

[0028] (First pressure sensor 34) The first pressure sensor 34 measures the pressure of the CO2 refrigerant expanded by the variable expansion valve 32. The first pressure sensor 34 may be disposed in either the second path 16 or the third path 18 between the variable expansion valve 32 and the compressor 6. In this embodiment, the first pressure sensor 34 is disposed in the third path 18 between the internal heat exchanger 10 and the compressor 6.

[0029] (Second pressure sensor 36) The second pressure sensor 36 measures the pressure of the CO2 refrigerant compressed by the compressor 6. The second pressure sensor 36 can be disposed in either the first path 14 or the second path 16 between the compressor 6 and the variable expansion valve 32. In this embodiment, the second pressure sensor 36 is disposed in the first path 14 between the compressor 6 and the water-cooled gas cooler 8.

[0030] (Temperature sensor) The heating mechanism 2 is provided with a plurality of temperature sensors for measuring the temperatures of the processing liquid, the industrial water (or the wastewater used in the processing equipment), and the CO2 refrigerant. The values ​​measured by each temperature sensor are all sent to the control means 4.

[0031] (Sensor that measures the temperature of the processing liquid) As sensors for measuring the temperature of the processing-contributing liquid, first and second temperature sensors 38, 40 are provided. The first temperature sensor 38 measures the temperature of the processing-contributing liquid flowing out of the water-cooled gas cooler 8. On the other hand, the second temperature sensor 40 measures the temperature of the processing-contributing liquid flowing into the water-cooled gas cooler 8.

[0032] (Sensor for measuring temperature of industrial water or wastewater) Third and fourth temperature sensors 42, 44 are provided as sensors for measuring the temperature of the industrial water or wastewater. The third temperature sensor 42 measures the temperature of the industrial water or wastewater from the processing equipment flowing out from the evaporator 12. Meanwhile, the fourth temperature sensor 44 measures the temperature of the industrial water or wastewater from the processing equipment flowing into the evaporator 12.

[0033] (Sensor that measures the temperature of CO2 refrigerant) Fifth to seventh temperature sensors 46, 48, 50 are provided as sensors for measuring the temperature of the CO2 refrigerant. The fifth temperature sensor 46 measures the temperature of the CO2 refrigerant sent out from the compressor 6. The sixth temperature sensor 48 measures the temperature of the CO2 refrigerant sent out from the water-cooled gas cooler 8. The seventh temperature sensor 50 measures the temperature of the CO2 refrigerant sent out from the internal heat exchanger 10 to the compressor 6.

[0034] (Processing contribution liquid) The processing-contributing liquid heated by the heating mechanism 2 is used, for example, in a dicing device that cuts a semiconductor wafer. As shown in FIG. 1, the dicing device includes a cutting means 52 for cutting a semiconductor wafer. The cutting means 52 is connected to a water-cooled gas cooler 8 by a pipeline 54. The water-cooled gas cooler 8 is also connected to a pure water facility 58 via a pipeline 56. Pure water as a processing-contributing liquid is sent from the pure water facility 58 to the water-cooled gas cooler 8 via the pipeline 56, and the pure water is heated to a predetermined temperature in the water-cooled gas cooler 8, after which the pure water heated to the predetermined temperature is sent to the cutting means 52 via the pipeline 54.

[0035] However, the processing equipment in which the processing-contributing liquid heated by the heating mechanism 2 is used is not limited to a dicing equipment, and various processing equipment such as a grinding equipment for grinding and thinning a semiconductor wafer can be the target. Note that the processing-contributing liquid includes not only fluids that are used as processing water such as cutting water and then discarded, but also circulating liquids that circulate in the processing equipment and the heating mechanism 2.

[0036] (Operation of heating mechanism 2) From here on, a description will be given of the operation of the above-mentioned heating mechanism 2. First, the basic operation of the heating mechanism 2 will be described, and then the operation in the case where the amount of heat applied to the processing contributing liquid is increased or decreased will be described.

[0037] (Basic operation) First, in the heating mechanism 2, when an operation command is input to the control means 4 by an operator, the setting unit 4a of the control means 4 sets the values ​​(set values) to be detected by each sensor in accordance with the input operation command. Specifically, the setting unit 4a sets the set temperature of the processing-contributing liquid and the set pressure and set temperature of the CO2 refrigerant. The set temperature of the processing-contributing liquid is the temperature input by the operator. The set pressure and set temperature of the CO2 refrigerant are determined by the control means 4 based on the set temperature of the processing-contributing liquid.

[0038] (Setting temperature of processing liquid: 1st and 2nd temperature) First, the setting unit 4a sets, as the set temperature of the processing-contributing liquid, a first temperature to be detected by the first temperature sensor 38 or a second temperature to be detected by the second temperature sensor 40. The first temperature is the set temperature of the processing-contributing liquid flowing out of the water-cooled gas cooler 8. On the other hand, the second temperature is the set temperature of the processing-contributing liquid flowing into the water-cooled gas cooler 8. For example, the first temperature can be set to 23°C, and the second temperature can be set to 20°C.

[0039] As shown in Fig. 1, when the processing-contributing liquid is used for disposable purposes, only the first temperature is set. In other words, when the pure water (processing-contributing liquid) in the pure water facility 58 is heated to a predetermined temperature and sent to the cutting means 52, and the pure water used in the cutting means 52 is not returned to the pure water facility 58, only the temperature (first temperature) of the pure water flowing out of the water-cooled gas cooler 8 is set.

[0040] On the other hand, when the processing contributing liquid is circulated between the processing device and the heating mechanism 2, both the first and second temperatures can be set. For example, this may be the case when the temperature of the processing contributing liquid discharged from the processing device is lower than the temperature of the processing contributing liquid before it is supplied to the processing device. In such a case, the processing contributing liquid is circulated between the processing device and the heating mechanism 2, and the processing contributing liquid heated by the heating mechanism 2 is sent to the processing device, so that both the first and second temperatures may be set.

[0041] (CO2 refrigerant pressure setting: first and second pressure values) Furthermore, the setting unit 4a sets a first pressure value to be detected by the first pressure sensor 34 and a second pressure value to be detected by the second pressure sensor 36 as the set pressure of the CO2 refrigerant. The first pressure value is the set pressure of the CO2 refrigerant expanded by the variable expansion valve 32. 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 compressed by the compressor 6. Since the second pressure value is the pressure of the CO2 refrigerant after compression, it is set to a value larger than the set pressure (first pressure value) of the CO2 refrigerant before compression. Specifically, the second pressure value may be about 10 MPa (absolute pressure).

[0042] (CO2 refrigerant set temperature: 5th and 7th temperatures) Furthermore, the setting unit 4a sets a fifth temperature to be detected by the fifth temperature sensor 46 and a seventh temperature to be detected by the seventh temperature sensor 50 as set temperatures of the CO2 refrigerant. The fifth temperature is the set temperature of the CO2 refrigerant sent out from the compressor 6. The fifth temperature may be set to, for example, 80°C. The seventh temperature is the set temperature of the CO2 refrigerant sent out from the internal heat exchanger 10 to the compressor 6. The seventh temperature may be, for example, about 10°C.

[0043] In this way, the setting unit 4a sets at least the first pressure value to be detected by the first pressure sensor 34, the second pressure value to be detected by the second pressure sensor 36, the first temperature to be detected by the first temperature sensor 38 or the second temperature to be detected by the second temperature sensor 40, the fifth temperature to be detected by the fifth temperature sensor 46, and the seventh temperature to be detected by the seventh temperature sensor 50.

[0044] The setting unit 4a may or may not set the temperature to be detected by the sixth temperature sensor 48. This is because the temperature of the CO2 refrigerant discharged from the water-cooled gas cooler 8 varies depending on the temperature and flow rate of the processing-contributing liquid sent to the water-cooled gas cooler 8 and the flow rate of the CO2 refrigerant, and is not fixed to a specific temperature.

[0045] (Control by control unit 4b) Once the set temperature of the processing-contributing liquid and the set pressure and temperature of the CO2 refrigerant have been set by the setting unit 4a, the control unit 4b controls the opening of the variable expansion valve 32, the rotation speed of the compressor 6, and the opening of the water control valve 20 according to a path defined by the set pressure values ​​(first and second pressure values) and temperatures (fifth and seventh temperatures) at which the CO2 refrigerant surrounds the critical point, so that the value of the first temperature sensor 38 or the second temperature sensor 40 becomes the set temperature (first temperature or second temperature).

[0046] (Opening degree of variable expansion valve 32) The pressure of the CO2 refrigerant can be adjusted by controlling the aperture of the variable expansion valve 32. When the aperture of the variable expansion valve 32 increases, the flow rate of the CO2 refrigerant passing through the variable expansion valve 32 increases, and the value of the second pressure sensor 36 decreases. On the other hand, when the aperture of the variable expansion valve 32 decreases, the flow rate of the CO2 refrigerant passing through the variable expansion valve 32 decreases, and the value of the second pressure sensor 36 increases.

[0047] (Compressor 6 rotation speed) In addition, the pressure of the CO2 refrigerant and the temperature of the processing-contributing liquid can be adjusted by controlling the rotation speed of the compressor 6. When the rotation speed of the compressor 6 increases, the amount of CO2 refrigerant drawn into the compressor 6 increases, and the value of the first pressure sensor 34 decreases. When the rotation speed of the compressor 6 increases, the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8 increases, and the values ​​of the first and second temperature sensors 38, 40 (temperature of the processing-contributing liquid) increase. Conversely, when the rotation speed of the compressor 6 decreases, the value of the first pressure sensor 34 increases and the values ​​of the first and second temperature sensors 38, 40 decrease.

[0048] (Opening degree of water control valve 20) By controlling the opening degree of the water control valve 20, the heat exchange capacity of the evaporator 12 can be maintained at an appropriate value. In other words, the difference between the value of the third temperature sensor 42 and the value of the fourth temperature sensor 44 can be maintained at a predetermined value.

[0049] The opening degree of the water control valve 20 is increased when the rotation speed of the compressor 6 is increased. When the rotation speed of the compressor 6 is increased, the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8 increases, and the flow rate of the CO2 refrigerant also increases in the evaporator 12. This increases the amount of cooling of the industrial water or wastewater by the CO2 refrigerant in the evaporator 12, and the difference between the value of the third temperature sensor 42 and the value of the fourth temperature sensor 44 increases. In such a case, by increasing the opening degree of the water control valve 20, the difference between the value of the third temperature sensor 42 and the value of the fourth temperature sensor 44 can be maintained at a predetermined value, and the heat exchange capacity of the evaporator 12 can be maintained at an appropriate value.

[0050] On the other hand, the opening degree of the water control valve 20 is reduced when the rotation speed of the compressor 6 is reduced. When the rotation speed of the compressor 6 is reduced, the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8 is reduced, and the flow rate of the CO2 refrigerant in the evaporator 12 is also reduced. This reduces the amount of cooling of the industrial water or wastewater by the CO2 refrigerant in the evaporator 12, and therefore the difference between the value of the third temperature sensor 42 and the value of the fourth temperature sensor 44 is reduced. In such a case, by reducing the opening degree of the water control valve 20, the difference between the value of the third temperature sensor 42 and the value of the fourth temperature sensor 44 can be maintained at a predetermined value, and the heat exchange capacity of the evaporator 12 can be maintained at an appropriate value.

[0051] That is, the control unit 4b of the control means 4 adjusts the opening of the water control valve 20 to provide heat to the CO2 refrigerant so that the temperature difference between the temperature of the industrial water or the wastewater used in the processing equipment detected by the third temperature sensor 42 and the temperature of the industrial water or the wastewater used in the processing equipment detected by the fourth temperature sensor 44 becomes a predetermined value.

[0052] (critical point) The critical point is generally a point specified by the temperature and pressure at which a substance goes into a supercritical state. In this embodiment, the critical point is a point specified by the critical temperature of 31.1°C and the critical pressure of 7.38MPa at which the refrigerant CO2 goes into a supercritical state. In Fig. 2, the critical point of CO2 is indicated by the symbol P. Fig. 2 is a pH diagram (Mollier diagram) of CO2, with the vertical axis indicating pressure and the horizontal axis indicating enthalpy.

[0053] (Path surrounding the critical point P) A path surrounding the critical point P (a path defined by set pressure values ​​and temperatures at which the CO2 refrigerant surrounds the critical point P) is, for example, path R passing through points A, B, C, D, E, and F in Fig. 2. Points A to F in Fig. 2 are points plotted based on the temperatures and pressures at points A to F shown in Fig. 1.

[0054] In this embodiment, as shown in FIG. 1, the outlet of the compressor 6 is point A, the outlet of the water-cooled gas cooler 8 is point B, the outlet of the second path 16 in the internal heat exchanger 10 is point C, the outlet of the variable expansion valve 32 is point D, the outlet of the evaporator 12 is point E, and the outlet of the third path 18 in the internal heat exchanger 10 is point F.

[0055] Specific values ​​of the pressure and temperature at points A to F are, for example, as shown in Fig. 2. That is, the pressure at points A, B, and C is, for example, 10 MPa, and the pressure at points D, E, and F is, for example, 4 MPa. Specific examples of the temperatures at points A to F are as follows: point A is about 80°C, point B is about 20°C, point C is about 8°C, points D and E are about 5°C, and point F is about 10°C.

[0056] From now on, the temperature, pressure, and enthalpy at each of points A to F will be explained using the following symbols. The temperature at point A is TA, the pressure is PA, and the enthalpy is EA. At point B, the temperature is TB, the pressure is PB, and the enthalpy is EB. The temperature at point C is TC, the pressure is PC, and the enthalpy is EC. At point D, TD is the temperature, PD is the pressure, and ED is the enthalpy. At point E, the temperature is TE, the pressure is PE, and the enthalpy is EE. The temperature at point F is TF, the pressure is PF, and the enthalpy is EF. This is explained as follows.

[0057] (CO2 refrigerant flow: Point F → Point A) When the above-described control is started, first, the CO2 refrigerant fed into the compressor 6 from point F is compressed by the compressor 6 to point A, where the CO2 refrigerant exceeds the critical point P. At this time, the temperature of the CO2 refrigerant changes (increases) from TF to TA, the pressure of the CO2 refrigerant changes (increases) from PF to PA, and the enthalpy of the CO2 refrigerant changes (increases) from EF to EA.

[0058] (Point A → Point B) Next, the CO2 refrigerant sent from point A to the water-cooled gas cooler 8 has heat removed by the water-cooled gas cooler 8 and reaches point B. At this time, the temperature of the CO2 refrigerant changes (decreases) from TA to TB, the pressure of the CO2 refrigerant does not change (PA = PB), and the enthalpy of the CO2 refrigerant changes (decreases) from EA to EB. The temperature difference between TA and TB and the enthalpy difference between EA and EB are used by the water-cooled gas cooler 8 to heat the processing liquid. In addition, the temperature TB of the CO2 refrigerant falls below the critical temperature, and the CO2 refrigerant at point B approaches a liquid state by entering a subcritical state.

[0059] (Point B → Point C) Next, the CO2 refrigerant sent from point B to the internal heat exchanger 10 has heat removed by the CO2 refrigerant sent from the evaporator 12 and reaches point C. At this time, the temperature of the CO2 refrigerant changes (decreases) from TB to TC, the pressure of the CO2 refrigerant does not change (PB=PC), and the enthalpy of the CO2 refrigerant changes (decreases) from EB to EC. In addition, because the temperature TC of the CO2 refrigerant falls further below the critical temperature, the CO2 refrigerant at point C becomes even closer to a liquid state.

[0060] (Point C → Point D) Next, the CO2 refrigerant sent from point C to the variable expansion valve 32 is decompressed by the variable expansion valve 32 and reaches point D. At this time, the temperature of the CO2 refrigerant changes (decreases) from TC to TD, the pressure of the CO2 refrigerant changes (decreases) from PC to PD, and the enthalpy of the CO2 refrigerant does not change (EC = ED). Also, the CO2 refrigerant at point D has reached the saturated liquid line and is in a mixed state of gas and liquid.

[0061] (Point D → Point E) Next, the CO2 refrigerant sent to the evaporator 12 from point D absorbs energy from the industrial water or wastewater used in the processing equipment by the evaporator 12 and reaches point E. At this time, the temperature of the CO2 refrigerant does not change (TD = TE) because the heat absorbed from the industrial water or wastewater is used to vaporize the liquid CO2 refrigerant. The pressure of the CO2 refrigerant also does not change (PD = PE). However, the enthalpy of the CO2 refrigerant changes (increases) from ED to EE. Point E is inside the saturated vapor line. For this reason, the CO2 refrigerant at point E becomes a gas that contains a small amount of liquid.

[0062] (Point E → Point F) Next, the CO2 refrigerant sent from point E to the internal heat exchanger 10 takes heat from the CO2 refrigerant sent from point B to the internal heat exchanger 10. Therefore, even if liquid remains in the CO2 refrigerant at point E, the liquid in the CO2 refrigerant becomes gas in the internal heat exchanger 10. That is, the CO2 refrigerant that reaches point F outside the saturated vapor line becomes gas. Therefore, the CO2 refrigerant that flows into the compressor 6 from point F becomes only gas. And the load on the compressor 6 can be reduced. When the CO2 refrigerant reaches point E from point F, the temperature of the CO2 refrigerant changes (increases) from TE to TF, the pressure of the CO2 refrigerant does not change (PE=PF), and the enthalpy of the CO2 refrigerant changes (increases) from EE to EF.

[0063] In this manner, in the heating mechanism 2, the control unit 4b controls the aperture of the variable expansion valve 32, the rotation speed of the compressor 6, and the aperture of the water control valve 20 according to the path R defined by the set pressure value and temperature where the CO2 refrigerant surrounds the critical point P, so that the value of the first temperature sensor 38 or the second temperature sensor 40 becomes the set temperature. As a result, the CO2 refrigerant flowing into the compressor 6 from point F becomes only gas, and liquid compression does not occur.

[0064] (Coefficient of Performance) Next, we will explain the coefficient of performance of the heating mechanism 2. The coefficient of performance is a coefficient used as a guide for energy consumption efficiency, and is obtained by dividing the heating capacity by the compression work.

[0065] The heating capacity is the capacity of the CO2 refrigerant to heat the processing liquid in the water-cooled gas cooler 8. Therefore, the heating capacity can be expressed as in the following formula 1 using the enthalpy before and after the water-cooled gas cooler 8. Heating capacity = EA-EB...Formula 1 EA is the enthalpy of the CO2 refrigerant at point A before passing through the water-cooled gas cooler 8. Also, EB is the enthalpy of the CO2 refrigerant at point B after passing through the water-cooled gas cooler 8.

[0066] The compression work is the work performed by the compressor 6. The compression work can be expressed as shown in Equation 7 using the enthalpy EA at point A (enthalpy after compression) and the enthalpy EF at point F (enthalpy before compression). Compression work = EA - EF Equation 2

[0067] From the above equations 1 and 2, the coefficient of performance can be expressed as shown in equation 3. Coefficient of performance (heating capacity / compression work) = (EA-EB) / (EA-EF) Equation 3

[0068] Then, the control means 4 controls the temperature, pressure, and enthalpy of the CO2 refrigerant so as to maximize the coefficient of performance derived from Equation 3. Specifically, the coefficient of performance is improved by increasing the heating capacity (EA-EB) and decreasing the compression work (EA-EF).

[0069] The enthalpies EA, EB, and EF at points A, B, and F can be calculated by detecting the temperature and pressure at each point and using the detected temperature and pressure based on the pH diagram.

[0070] The temperatures of the CO2 refrigerant at points A, B, and F can be detected by the following sensors: the temperature TA at point A can be detected by the fifth temperature sensor 46, the temperature TB at point B can be detected by the sixth temperature sensor 48, and the temperature TF at point F can be detected by the seventh temperature sensor 50.

[0071] In addition, the pressures of the CO2 refrigerant at points A, B, and F can be detected by the following sensors. That is, the pressure PA at point A can be detected by the second pressure sensor 36, the pressure PB at point B can be detected by the second pressure sensor 36, and the pressure PF at point F can be detected by the first pressure sensor 34.

[0072] The enthalpy at points A, B, and F can be calculated based on the pH diagram using the above temperature and pressure. That is, the enthalpy EA at point A can be calculated based on the pH diagram using the temperature TA and pressure PA at point A, the enthalpy EB at point B can be calculated based on the pH diagram using the temperature TB and pressure PB at point B, and the enthalpy EF at point F can be calculated based on the pH diagram using the temperature TF and pressure PF at point F.

[0073] When performing the above control to set the temperature of the processing-contributing liquid to the set temperature, the control means 4 uses the EA, EB, and EF detectable as described above to increase the heating capacity (EA-EB) and reduce the compression work (EA-EF) to improve the coefficient of performance. For example, the control means 4 can adjust the pressure of the CO2 refrigerant to the set pressure value by reducing the opening of the variable expansion valve 32 to increase the value of the second pressure sensor 36, or by increasing the opening of the variable expansion valve 32 to decrease the value of the second pressure sensor 36, thereby controlling the coefficient of performance (heating capacity / compression work).

[0074] Next, an operation in the case where the amount of heat applied to the processing contributing liquid used in the processing device is increased or decreased (that is, where the set temperature of the processing contributing liquid is changed) will be described.

[0075] (When reducing the amount of heat in the processing liquid) First, a case where the amount of heat of the processing-contributing liquid used in the processing device is reduced (a case where the set temperature of the processing-contributing liquid is lowered) will be described. In this case, the control unit 4b of the control means 4 reduces the rotation speed of the compressor 6. This reduces the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8, so that the amount of heat of the processing-contributing liquid can be reduced. As a result, the value of the first temperature sensor 38 or the second temperature sensor 40 decreases.

[0076] In this case, even if the rotation speed of the compressor 6 reaches the lower limit of the allowable rotation speed, the value of the first temperature sensor 38 or the value of the second temperature sensor 40 may not drop to the set temperature (first temperature or second temperature). In such a case, the control unit 4b further operates the variable bypass valve 28, which is normally closed, from closed to open to increase the opening degree, thereby reducing the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8. This makes it possible to decrease the value of the first temperature sensor 38 or the value of the second temperature sensor 40 to the set temperature (first temperature or second temperature) without decreasing the rotation speed of the compressor 6 to a rotation speed lower than the lower limit of the allowable rotation speed.

[0077] However, when the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8 is reduced, the pressure of the CO2 refrigerant may deviate significantly from the set value. That is, the value of the first pressure sensor 34 may exceed the first pressure value, and the value of the second pressure sensor 36 may fall below the second pressure value.

[0078] Therefore, the control unit 4b appropriately reduces the opening of the variable expansion valve 32 according to the reduction in the set temperature of the processing-contributing liquid. This reduces the value of the first pressure sensor 34 to the first pressure value and increases the value of the second pressure sensor 36 to the second pressure value. Therefore, in the heating mechanism 2, even if the set temperature of the processing-contributing liquid is reduced, the suction pressure and discharge pressure of the compressor 6 do not fluctuate significantly, and therefore highly efficient heating control can be achieved.

[0079] In this way, when the control unit 4b reduces the amount of heat of the processing-contributing liquid, it reduces the rotation speed of the compressor 6 to reduce the flow rate of the CO2 refrigerant flowing through the water-cooled gas cooler 8, and at that time, it increases the opening of the variable bypass valve 28 in the bypass path 30 to reduce the flow rate of the CO2 refrigerant flowing through the water-cooled gas cooler 8 so that the rotation speed of the compressor 6 does not fall below the lower limit value.

[0080] (When increasing the amount of heat in the processing liquid) Conversely, when the heating amount of the processing-contributing liquid used in the processing device is increased in the heating mechanism 2 (when the set temperature of the processing-contributing liquid is increased), the control unit 4b of the control means 4 increases the rotation speed of the compressor 6. This increases the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8, so that the heating amount of the processing-contributing liquid can be increased. As a result, the value of the first temperature sensor 38 or the second temperature sensor 40 increases.

[0081] However, when the flow rate of the CO2 refrigerant in the water-cooled gas cooler 8 is increased, the pressure of the CO2 refrigerant may deviate significantly from the set value. That is, the value of the first pressure sensor 34 may fall below the first pressure value, and the value of the second pressure sensor 36 may exceed the second pressure value.

[0082] Therefore, the control unit 4b appropriately increases the opening of the variable expansion valve 32 according to the increase in the set temperature of the processing-contributing liquid. This makes it possible to increase the value of the first pressure sensor 34 to the first pressure value and decrease the value of the second pressure sensor 36 to the second pressure value. Therefore, in the heating mechanism 2, even if the set temperature of the processing-contributing liquid is increased, the suction pressure and discharge pressure of the compressor 6 do not fluctuate significantly, and therefore highly efficient heating control can be realized.

[0083] However, when the opening degree of the variable expansion valve 32 is increased, the flow rate of the CO2 refrigerant in the evaporator 12 increases. This increases the risk that the liquid CO2 refrigerant will be sucked into the compressor 6. However, in the heating mechanism 2 of this embodiment, the CO2 refrigerant from the evaporator 12 and the CO2 refrigerant from the water-cooled gas cooler 8 exchange heat in the internal heat exchanger 10. In this heat exchange, the CO2 refrigerant from the evaporator 12 takes heat from the CO2 refrigerant from the water-cooled gas cooler 8. Therefore, even if liquid remains in the CO2 refrigerant from the evaporator 12, the liquid in the CO2 refrigerant becomes gas in the internal heat exchanger 10.

[0084] In this way, when the control unit 4b increases the amount of heating of the processing-contributing liquid, it increases the opening of the variable expansion valve 32 and the rotation speed of the compressor 6 to increase the flow rate of the CO2 refrigerant flowing through the evaporator 12, and as a result, the liquid CO2 remaining in the CO2 refrigerant discharged from the evaporator 12 is vaporized in the internal heat exchanger 10, thereby reducing the burden on the compressor 6.

[0085] As described above, in the heating mechanism 2, the opening of the variable expansion valve 32, the rotation speed of the compressor 6, and the opening of the water control valve 20 are controlled according to the path R defined by the set pressure value and temperature at which the CO2 refrigerant surrounds the critical point P so that the value of the first temperature sensor 38 or the second temperature sensor 40 becomes the set temperature, thereby improving the coefficient of performance.

[0086] Regarding the arrangement of the compressor 6, the water-cooled gas cooler 8, the internal heat exchanger 10 and the evaporator 12, it is preferable to install the water-cooled gas cooler 8 above the compressor 6, the internal heat exchanger 10 and the evaporator 12, as shown in FIG. 3.

[0087] When the CO2 refrigerant reaches a supercritical state, the lubricating oil in the compressor 6 tends to dissolve in the CO2 refrigerant and easily flow out of the compressor 6. If the lubricating oil in the compressor 6 that has dissolved in the supercritical CO2 refrigerant accumulates in the water-cooled gas cooler 8, the internal heat exchanger 10, etc. and does not return to the compressor 6, abnormal wear of the compressor 6 may occur.

[0088] 3, by installing the water-cooled gas cooler 8 above the compressor 6, the installation area of ​​the entire heating mechanism 2 can be reduced while the flow direction of the supercritical CO2 refrigerant in the water-cooled gas cooler 8 and the internal heat exchanger 10 can be made to be the direction of gravity (i.e., from top to bottom). Therefore, the lubricating oil dissolved in the supercritical CO2 refrigerant in the compressor 6 can be prevented from accumulating in the water-cooled gas cooler 8 and the internal heat exchanger 10, and the lubricating oil can be returned to the compressor 6. As a result, abnormal wear of the compressor 6 can be prevented.

[0089] The CO2 refrigerant expanded by the variable expansion valve 32 flows in the anti-gravity direction (from bottom to top) in the evaporator 12 and the internal heat exchanger 10, but it is preferable to make the difference in height from the outlet of the evaporator 12 to the compressor 6 as small as possible by making the lower end positions of the compressor 6, the internal heat exchanger 10 and the evaporator 12 the same height, thereby making it easier for the lubricating oil to return to the compressor 6.

[0090] Furthermore, when the compressor 6 is restarted after it has been stopped, it is preferable to repeat operation at the intermediate speed and operation at the minimum speed several times for a predetermined period of time each while maintaining the variable expansion valve 32 and the variable bypass valve 28 at a predetermined opening degree, as shown in Fig. 4. This allows the lubricating oil that has accumulated in the internal heat exchanger 10 and the evaporator 12 when the compressor 6 was stopped to be efficiently returned to the compressor 6. [Explanation of symbols]

[0091] 2:Heating mechanism 4: Control means 4a: Setting section 4b: Control section 6: Compressor 8: Water-cooled gas cooler 10: Internal heat exchanger 12: Evaporator 14: First Route 16: Second Path 18: The third path 20: Water control valve 22: The Fourth Path 24: First connection 26: Second connection 28: Variable bypass valve 30: Bypass route 32: Variable expansion valve 34: First pressure sensor 36: Second pressure sensor 38: First temperature sensor 40: Second temperature sensor 42: Third temperature sensor 44: Fourth temperature sensor 46: Fifth temperature sensor 48: Sixth temperature sensor 50: Seventh temperature sensor P: critical point R: A path surrounding a critical point

Claims

1. A heating mechanism for heating a processing liquid used in a processing device, A control means; CO ２ A compressor that compresses a refrigerant; The CO compressed by the compressor and carrying the heat of compression ２ A water-cooled gas cooler that removes heat from the refrigerant and provides heat to a processing liquid used in the processing equipment; CO that has lost heat ２ an internal heat exchanger into which a refrigerant is pumped; CO discharged from the internal heat exchanger ２ an evaporator that vaporizes a refrigerant and generates heat of vaporization; a first passage connecting the compressor and the water-cooled gas cooler; a second passage connecting the water-cooled gas cooler and the evaporator; a third passage connecting the evaporator and the compressor; Industrial water or wastewater used in a processing plant is introduced into the evaporator, and CO ２ a fourth path including a water control valve for providing heat to the refrigerant; a bypass passage connected to the first passage by a first connecting portion connected to the first passage and a second connecting portion connected to the second passage, the bypass passage including a variable bypass valve; The internal heat exchanger is configured to convert the CO ２ The refrigerant is CO sent out from the water-cooled gas cooler. ２ a heat exchanger disposed across the second path and the third path so as to remove heat from the refrigerant; The second pathway is CO ２ a variable expansion valve for adjusting a flow rate of the refrigerant is disposed between the internal heat exchanger and the second connection; A CO 2 gas is introduced into either the second path or the third path between the variable expansion valve and the compressor. ２ a first pressure sensor for measuring a pressure of the refrigerant is provided; The CO compressed by the compressor is supplied to either the first path or the second path between the compressor and the variable expansion valve. ２ a second pressure sensor is provided to measure the pressure of the refrigerant; A first temperature sensor for measuring a temperature of a processing liquid used in a processing device flowing out from the water-cooled gas cooler; A second temperature sensor that measures the temperature of the processing liquid flowing into the water-cooled gas cooler; a third temperature sensor for measuring the temperature of the industrial water or wastewater used in a processing device flowing out from the evaporator; a fourth temperature sensor for measuring the temperature of industrial water or wastewater used in a processing device flowing into the evaporator; CO discharged from the compressor ２ a fifth temperature sensor for measuring the temperature of the refrigerant; CO discharged from the water-cooled gas cooler ２ a sixth temperature sensor for measuring a temperature of the refrigerant; CO sent from the internal heat exchanger to the compressor ２ a seventh temperature sensor disposed in the third path for measuring a temperature of the refrigerant; the control means includes a setting unit that sets at least a first pressure value to be detected by the first pressure sensor, a second pressure value to be detected by the second pressure sensor, a first temperature to be detected by the first temperature sensor or a second temperature to be detected by the second temperature sensor, a fifth temperature to be detected by the fifth temperature sensor, and a seventh temperature to be detected by the seventh temperature sensor; The CO ２ A heating mechanism that controls the opening of the variable expansion valve, the rotation speed of the compressor, and the opening of the water control valve according to a path defined by the set pressure value and temperature that surrounds the critical point of the refrigerant identified as a critical temperature of 31.1°C and a critical pressure of 7.38 MPa.

2. When the control means reduces the amount of heat of the processing liquid used in the processing device, the control means reduces the rotation speed of the compressor to reduce the amount of CO flowing through the water-cooled gas cooler. ２ The flow rate of the refrigerant is reduced, and at that time, the opening degree of the variable bypass valve of the bypass path is increased so that the rotation speed of the compressor does not fall below a lower limit value, thereby reducing the amount of CO flowing through the water-cooled gas cooler. ２ 2. The heating mechanism of claim 1, further comprising: a reduced flow rate of refrigerant.

3. When the amount of heat of the processing liquid used in the processing device is increased, the control means increases the opening degree of the variable expansion valve and increases the rotation speed of the compressor to reduce the amount of CO flowing through the evaporator. ２ Increasing the flow rate of the refrigerant and the associated CO ２ Liquid CO remaining in the refrigerant ２ 2. The heating mechanism according to claim 1, wherein the heat generated by the refrigerant is vaporized in the internal heat exchanger to reduce a load on the compressor.

4. The control means adjusts the opening of the water control valve so that the temperature difference between the temperature of the industrial water or the wastewater used in the processing equipment detected by the third temperature sensor and the temperature of the industrial water or the wastewater used in the processing equipment detected by the fourth temperature sensor becomes a predetermined value, thereby controlling the CO ２ 2. The heating mechanism of claim 1, wherein heat is applied to the refrigerant.

5. 2. The heating mechanism according to claim 1, wherein the control means adjusts the pressure to the set pressure value by reducing the opening of the variable expansion valve to increase the value of the second pressure sensor, and by increasing the opening of the variable expansion valve to decrease the value of the second pressure sensor, thereby controlling the coefficient of performance (heating capacity / compression work).

6. The outlet of the compressor is at point A. The outlet of the water-cooled gas cooler is at point B. The outlet of the second passage in the internal heat exchanger is at point C; The outlet of the variable expansion valve is at point D. The outlet of the evaporator is point E. The outlet of the third passage in the internal heat exchanger is at point F; The temperature at point A is TA, the pressure is PA, and the enthalpy is EA. The temperature at point B is TB, the pressure is PB, and the enthalpy is EB. The temperature at point C is TC, the pressure is PC, and the enthalpy is EC. The temperature at point D is TD, the pressure is PD, and the enthalpy is ED. The temperature at point E is TE, the pressure is PE, and the enthalpy is EE. If the temperature at point F is TF, the pressure is PF, and the enthalpy is EF, CO fed into the compressor from point F ２ The refrigerant is compressed by the compressor to reach point A where the critical point is exceeded, and the temperature changes from TF to TA, the pressure changes from PF to PA, and the enthalpy changes from EF to EA, respectively. CO sent from point A to the water-cooled gas cooler ２ The refrigerant loses heat through the water-cooled gas cooler and reaches point B. The temperature changes from TA to TB, the pressure does not change (PA=PB), and the enthalpy changes from EA to EB. The temperature difference between TA and TB and the enthalpy difference between EA and EB are used by the water-cooled gas cooler to heat the processing liquid. The temperature TB falls below the critical temperature and CO ２ The refrigerant becomes closer to liquid when it reaches a subcritical state. CO sent from point B to the internal heat exchanger ２ The refrigerant is CO sent from the evaporator. ２ Heat is absorbed by the refrigerant and reaches point C, the temperature changes from TB to TC, the pressure does not change (PB = PC), the enthalpy changes from EB to EC, and the temperature TC falls further below the critical temperature and CO ２ The refrigerant becomes even closer to a liquid state. CO fed from point C to the variable expansion valve ２ The refrigerant is decompressed by the variable expansion valve to reach point D, the temperature changes from TC to TD, the pressure changes from PC to PD, and the enthalpy does not change (EC = ED), and CO ２ The refrigerant reaches the saturated liquid line. CO fed from point D to the evaporator ２ The refrigerant absorbs energy from industrial water or wastewater used in a processing plant by the evaporator and reaches point E. The temperature and pressure do not change (TD=TE, PD=PE), and the enthalpy changes from ED to EE. Point E is inside the saturated vapor line and is converted into CO. ２ The refrigerant becomes a gas containing liquid, CO sent from point E to the internal heat exchanger ２ The refrigerant is CO sent from point B to the internal heat exchanger. ２ The refrigerant absorbs heat and turns into a gas, reaching point F. The temperature changes from TE to TF, the pressure does not change (PE = PF), and the enthalpy changes from EE to EF, reaching point A. The control means 6. The heating mechanism according to claim 1, wherein the temperature, pressure, and enthalpy are controlled so that the coefficient of performance (heating capacity / compression work)=(EA-EB) / (EA-EF) is maximized.

7. The temperature TA at the point A is detected by the fifth temperature sensor; The temperature T at point B is detected by the sixth temperature sensor; The temperature TF at the point F is detected by the seventh temperature sensor; The pressure PA at point A is detected by the second pressure sensor; The pressure P at point B is detected by the second pressure sensor; The pressure PF at point F is detected by the first pressure sensor; The enthalpy EA at point A is detected based on the ph diagram, The enthalpy EB at point B is detected based on the ph diagram, The enthalpy EF at point F is detected based on the ph diagram, The control means Coefficient of performance (heating capacity / compression work)=(EA-EB) / (EA-EF) 7. The heating mechanism according to claim 6, wherein the heating capacity is increased and the compression work is reduced by the above formula, thereby improving the coefficient of performance.

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