Water cooling system of a cascade refrigeration system, control method thereof and environmental test chamber

Abstract

The application discloses a water cooling system of a cascade refrigeration system, a control method of the water cooling system and an environmental test chamber. The water cooling system comprises a first electromagnetic valve, a second electromagnetic valve, a three-way valve, a water pump, a water tower, an environmental temperature detection unit, a cooling water temperature detection unit, a pressure detection unit and a control unit. The environmental temperature detection unit is used for detecting an environmental temperature. The cooling water temperature detection unit is arranged at a second end of the water tower and is used for detecting a temperature of cooling water of the water tower. The pressure detection unit is arranged in the cascade refrigeration system and is used for detecting a pressure parameter of the cascade refrigeration system. The control unit is configured to acquire a target water inlet temperature of the cooling water entering the cascade refrigeration system, the environmental temperature, the temperature of the cooling water of the water tower and the pressure parameter, and control opening or closing of the first electromagnetic valve or the second electromagnetic valve according to a preset condition met by the target water inlet temperature, the environmental temperature, the temperature of the cooling water of the water tower and the pressure parameter, so as to adjust an opening degree of the three-way valve.

Description

Technical Field

[0001] This invention relates to the field of refrigeration technology, and in particular to a water-cooling system for a cascade refrigeration system, its control method, and an environmental test chamber. Background Technology

[0002] With the continuous advancement of living standards and technology, the industry demands increasingly higher product reliability. However, the technical requirements for the configuration and water temperature of water-cooled condenser terminals in environmental testing equipment are usually controlled by the users themselves, making it difficult to guarantee product reliability.

[0003] Most existing products on the market do not include water pumps in the unit, only pressure regulating valves. However, due to their lag and limited adjustment range, selecting an external cooling tower that is too large or too small will affect system operation. For example, if the cooling tower is too large and the ambient temperature is low: the system cooling water temperature will be low, resulting in lower condensing and evaporating pressures in the R404A system of the cascade system, leading to lower condensing and evaporating pressures in the R23 system. In severe cases, this can cause the compressor to operate under negative pressure, posing a risk to reliability. If the cooling tower is too small and the ambient temperature is high: the system cooling water temperature will be high, resulting in higher condensing and evaporating pressures in the R404A system of the cascade system, leading to higher condensing and evaporating pressures in the R23 system, higher system energy consumption, and potentially affecting the standby pressure of the R23 system, posing a risk of pressure tank depressurization. Therefore, temperature control of the cooling water in the refrigeration system is crucial. Summary of the Invention

[0004] This invention provides a water-cooling system for a cascade refrigeration system, its control method, and an environmental test chamber, to control the cooling water temperature of the refrigeration system within a reasonable range and ensure the safe and reliable operation of the system.

[0005] According to one aspect of the present invention, a water cooling system for a cascade refrigeration system is provided, the water cooling system of the cascade refrigeration system comprising: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit;

[0006] The cascade refrigeration system is configured such that its first end is connected to both the first end of the water tower and the first solenoid valve; its first end is connected to both the first and second solenoid valves; its second end is connected to the second end of the water tower; its third end is connected to the water pump; the water pump is also connected to the second end of the cascade refrigeration system; and the second solenoid valve is also connected to the tap water supply. An ambient temperature detection unit is used to detect the ambient temperature. A cooling water temperature detection unit is located at the second end of the water tower and is used to detect the temperature of the cooling water in the water tower. A pressure detection unit is located within the cascade refrigeration system and is used to detect the pressure parameters of the cascade refrigeration system.

[0007] The control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit, respectively.

[0008] The control unit is configured to: acquire the target inlet water temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters; and control the opening or closing of the first solenoid valve or the second solenoid valve according to preset conditions satisfied by the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve.

[0009] Optionally, the control unit is further configured to: determine whether a first preset condition is met based on the target inlet water temperature, the ambient temperature, and the temperature of the cooling water in the water tower; if the condition is met, control the first solenoid valve to open and the second solenoid valve to close.

[0010] Alternatively, obtain the first opening degree of the three-way valve when the first solenoid valve is open; and determine whether the second preset condition is met based on the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, the pressure parameter, and the first opening degree. If the condition is met, control the second solenoid valve to open and the first solenoid valve to close, and calculate the second opening degree of the three-way valve when the second solenoid valve is open.

[0011] Optionally, the first preset condition is: whether the ambient temperature is less than a preset ambient temperature, or whether the temperature of the cooling water in the water tower is less than the difference between the target inlet water temperature and the preset temperature error.

[0012] Optionally, the water cooling system of the cascade refrigeration system further includes: an outlet water temperature detection unit, which is disposed at the first end of the cascade refrigeration system and electrically connected to the control unit, for detecting the outlet water temperature of the cooling water output from the cascade refrigeration system;

[0013] The formula for calculating the first opening is:

[0014]

[0015] Where A is the first opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T0 is the temperature of the cooling water in the water tower, TS is the target inlet water temperature, and K is the opening degree correction coefficient.

[0016] Optionally, the pressure detection unit includes a first pressure detection unit, which is disposed on the low-temperature side of the cascade refrigeration system and electrically connected to the control unit, for detecting the pressure at the outlet of the evaporator on the low-temperature side;

[0017] The control unit is further configured to: when the pressure at the outlet of the low-temperature side evaporator is a first preset pressure, and the temperature of the cooling water in the water tower is less than the sum of the errors between the target inlet water temperature and the preset temperature, control the first solenoid valve to open, the three-way valve to fully open, and the second solenoid valve to close.

[0018] Optionally, the pressure detection unit further includes a second pressure detection unit, which is disposed on the high-temperature side of the cascade refrigeration system and electrically connected to the control unit, for detecting the discharge pressure of the compressor on the high-temperature side;

[0019] The second preset condition is: the ambient temperature is greater than or equal to the preset ambient temperature, the first opening degree is less than the preset opening degree, the temperature of the cooling water in the water tower is greater than the sum of the errors between the target inlet water temperature and the preset temperature, and the exhaust pressure of the high-temperature side compressor is greater than or equal to the second preset pressure.

[0020] Optionally, the water cooling system of the cascade refrigeration system further includes: an outlet water temperature detection unit, which is disposed at the first end of the cascade refrigeration system and electrically connected to the control unit, for detecting the outlet water temperature of the cooling water output from the cascade refrigeration system;

[0021] An inlet water temperature detection unit is installed at the second end of the cascade refrigeration system and is electrically connected to the control unit. It is used to detect the inlet water temperature of the cooling water entering the cascade refrigeration system.

[0022] The tap water temperature detection unit is connected to the tap water terminal and electrically connected to the control unit, and is used to detect the temperature of the tap water.

[0023] The formula for calculating the second opening is:

[0024]

[0025] Wherein, B is the second opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T2 is the inlet temperature of the cooling water entering the cascade refrigeration system, T3 is the temperature of the tap water, and K is the opening degree correction coefficient.

[0026] Optionally, the control unit is further configured to: when the exhaust pressure of the high-temperature side compressor is a second preset pressure, and the temperature of the cooling water in the water tower is greater than the sum of the error between the target inlet water temperature and the preset temperature, control the second solenoid valve to open, the three-way valve to fully open, and the first solenoid valve to close.

[0027] According to another aspect of the present invention, an environmental test chamber is provided, which includes a water cooling system of the cascade refrigeration system as described in the first aspect.

[0028] According to another aspect of the present invention, a control method for a water-cooled system of a cascade refrigeration system is provided. This control method is applied to the water-cooled system of a cascade refrigeration system, which includes: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The first end of the cascade refrigeration system is connected to the first end of the water tower and the first solenoid valve, the first end of the three-way valve is connected to the first solenoid valve and the second solenoid valve, and the second end of the three-way valve is connected to the second solenoid valve of the water tower. The system includes a three-way valve connected to a water pump, which is also connected to the second end of the cascade refrigeration system. The second solenoid valve is also connected to the tap water supply. An ambient temperature detection unit is used to detect the ambient temperature. A cooling water temperature detection unit is located at the second end of the water tower and is used to detect the temperature of the cooling water in the water tower. A pressure detection unit is located in the cascade refrigeration system and is used to detect the pressure parameters of the cascade refrigeration system. The control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit, respectively.

[0029] The control method includes:

[0030] The target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters are obtained.

[0031] The opening or closing of the first or second solenoid valve is controlled according to the preset conditions satisfied by the target inlet water temperature, the ambient temperature, the cooling water temperature of the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve.

[0032] The technical solution of this invention provides a water-cooling system and control method for a cascade refrigeration system, as well as an environmental test chamber. The water-cooling system includes: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The first end of the cascade refrigeration system is connected to the first end of the water tower and the first solenoid valve. The first end of the three-way valve is connected to the first and second solenoid valves. The second end of the three-way valve is connected to the second end of the water tower. The third end of the three-way valve is connected to the water pump, which is also connected to the second end of the cascade refrigeration system. The second solenoid valve is also connected to a tap water supply. The ambient temperature detection unit is used to detect ambient temperature. Temperature; The cooling water temperature detection unit is located at the second end of the water tower to detect the temperature of the cooling water in the water tower; the pressure detection unit is located in the cascade refrigeration system to detect the pressure parameters of the cascade refrigeration system; the control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit respectively; the control unit is configured to: acquire the target inlet water temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters; and control the opening or closing of the first solenoid valve or the second solenoid valve according to the preset conditions satisfied by the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve. Therefore, by setting up a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit, the system can detect and acquire in real time the target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters. Based on the real-time acquired target inlet temperature of the cooling water entering the cascade refrigeration system, the system can determine the preset conditions that need to be met and control the opening or closing of the first or second solenoid valve to adjust the opening of the three-way valve, so that the temperature of the cooling water entering the cascade refrigeration system is controlled within a reasonable range, thereby controlling the operating pressure of the system within a reasonable range and ensuring the safe and reliable operation of the system.

[0033] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the water cooling system of a cascade refrigeration system provided in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the water cooling system of another cascade refrigeration system provided in this embodiment of the invention.

[0037] Figure 3 This is a schematic diagram of the fully open structure of a water-cooling system of a cascade refrigeration system provided in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the fully open structure of the water cooling system of another cascade refrigeration system provided in this embodiment of the invention;

[0039] Figure 5 This is a schematic diagram of the structure of a water-cooling system of a cascade refrigeration system provided in an embodiment of the present invention;

[0040] Figure 6 This is a flowchart of a control method for a water-cooled system of a cascade refrigeration system provided in an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] Figure 1 This is a schematic diagram of the water-cooling system of a cascade refrigeration system provided in an embodiment of the present invention. (Reference) Figure 1The water cooling system of the cascade refrigeration system 100 includes: a first solenoid valve S1, a second solenoid valve S2, a three-way valve S3, a water pump B0, a water tower ST, an ambient temperature detection unit TH, a cooling water temperature detection unit T0, a pressure detection unit P0, and a control unit 200. The first end of the cascade refrigeration system 100 is connected to the first end of the water tower ST and the first solenoid valve S1. The first end of the three-way valve S3 is connected to the first solenoid valve S1 and the second solenoid valve S2. The second end of the three-way valve S3 is connected to the second end of the water tower ST. The third end of the three-way valve S3 is connected to the water pump B0, which is also connected to the second end of the cascade refrigeration system 100. The second solenoid valve S2 is also connected to the tap water supply ZL. The ambient temperature detection unit TH is used to detect the ambient temperature. The cooling water temperature detection unit T0... Unit 0 is installed at the second end of water tower ST to detect the temperature of cooling water in water tower ST; pressure detection unit P0 is installed in cascade refrigeration system 100 to detect the pressure parameters of cascade refrigeration system 100; control unit 200 is electrically connected to first solenoid valve S1, second solenoid valve S2, three-way valve S3, ambient temperature detection unit TH, cooling water temperature detection unit T0 and pressure detection unit P0 respectively; control unit 200 is configured to: acquire the target inlet water temperature of cooling water entering cascade refrigeration system, ambient temperature, temperature of cooling water in water tower and pressure parameters; and control the opening or closing of first solenoid valve S1 or second solenoid valve S2 according to the preset conditions satisfied by the target inlet water temperature, ambient temperature, temperature of cooling water in water tower and pressure parameters, so as to adjust the opening degree of three-way valve S3.

[0044] The control unit 200 can be a PLC controller, etc., and can be set according to the actual situation. No specific limitation is made here.

[0045] The ambient temperature detection unit TH is located on the outside of the system and is used to detect the ambient temperature outside the system in real time and send it to the control unit 200.

[0046] For example, the first end of the cascade refrigeration system is the outlet of the cooling water output from the cascade refrigeration system, and correspondingly, the second end is the inlet of the cooling water (the medium used to provide heat exchange for the cascade refrigeration system) entering the cascade refrigeration system.

[0047] For example, the first end of the three-way valve S3 is the first inlet end, the second end is the second inlet end, and the third end is the outlet end. Assuming the three-way valve S3 has a certain opening degree, when the first solenoid valve S1 is open and the second solenoid valve S2 is closed, the first inlet end of the three-way valve S3 is connected to the first solenoid valve S1; when the second solenoid valve S2 is open and the first solenoid valve S1 is closed, the first inlet end of the three-way valve S3 is connected to the second solenoid valve S2. Assuming the three-way valve S3 is fully open (100% opening), and the first solenoid valve S1 is open and the second solenoid valve S2 is closed, the second inlet end of the three-way valve S3 is closed, and cooling water from the water tower cannot enter the three-way valve S3. Assuming the three-way valve S3 is fully open (100% opening), and the second solenoid valve S2 is open and the first solenoid valve S1 is closed, the second inlet end of the three-way valve S3 is closed, and cooling water from the water tower cannot enter the three-way valve S3. When the three-way valve S3 is fully open (i.e., 100% opening) and both the first solenoid valve S1 and the second solenoid valve S2 are closed, the first inlet of the three-way valve S3 is closed and the second inlet is open. At this time, the cooling water of the water tower enters the three-way valve S3.

[0048] The ambient temperature detection unit TH and the cooling water temperature detection unit T0 can be temperature sensors. The pressure detection unit can be a pressure sensor.

[0049] Among them, the three-way valve S3 can be an electric proportional three-way valve.

[0050] The control unit 200 is electrically connected to the first solenoid valve S1 and is used to control the opening or closing of the first solenoid valve S1. The control unit 200 is also electrically connected to the second solenoid valve S2 and is used to control the opening or closing of the second solenoid valve S2. The control unit 200 is further electrically connected to the three-way valve S3 and is used to adjust the opening degree of the three-way valve S3.

[0051] The target inlet temperature of the cooling water entering the cascade refrigeration system can be set according to the actual situation, and no specific limit is made here.

[0052] In this system, the first solenoid valve S1 and the second solenoid valve S2 will not be open simultaneously. The opening or closing of the first solenoid valve S1 or the second solenoid valve S2 is controlled according to preset conditions satisfied by the target inlet water temperature, ambient temperature, and the temperature and pressure parameters of the cooling water in the water tower, thereby adjusting the opening of the three-way valve. This includes: controlling the first solenoid valve S1 to open and the second solenoid valve S2 to close, thereby adjusting the opening of the three-way valve S3; or controlling the second solenoid valve S2 to open and the first solenoid valve S1 to close, thereby adjusting the opening of the three-way valve S3; or controlling both the first solenoid valve S1 and the second solenoid valve S2 to close, thereby adjusting the opening of the three-way valve S3.

[0053] In existing technologies, most units do not equip themselves with water pumps, but only with pressure regulating valves. However, due to their lag and limited adjustment range, the operation of the system will be affected if the external cooling tower is too large or too small. For example, if the cooling tower is too large and the ambient temperature is low: the system cooling water temperature will be low, resulting in lower condensing and evaporating pressures in the R404A system of the cascade system, leading to lower condensing and evaporating pressures in the R23 system. In severe cases, this can cause the compressor to operate under negative pressure, posing a risk to reliability. If the cooling tower is too small and the ambient temperature is high: the system cooling water temperature will be high, resulting in higher condensing and evaporating pressures in the R404A system of the cascade system, leading to higher condensing and evaporating pressures in the R23 system, higher system energy consumption, and in severe cases, affecting the standby pressure of the R23 system, posing a risk of pressure tank depressurization. To address this, this invention provides a water-cooling system for a cascade refrigeration system. By configuring a first solenoid valve S1, a second solenoid valve S2, a three-way valve S3, an ambient temperature detection unit TH, a cooling water temperature detection unit T0, and a pressure detection unit P0, the system continuously monitors and acquires the target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature and pressure parameters of the cooling water in the water tower, and the target inlet temperature. Based on the real-time acquired data on the target inlet temperature, ambient temperature, water tower temperature, pressure parameters, and target inlet temperature, the system determines the specific preset conditions that must be met and controls the opening or closing of either the first solenoid valve S1 or the second solenoid valve S2 to adjust the opening of the three-way valve. This ensures the opening of the three-way valve is set to a reasonable value, thereby controlling the temperature of the cooling water entering the cascade refrigeration system within a reasonable range. This solves the problems of unreliable and unsafe system operation caused by excessively high or low cooling water temperatures in existing technologies, thus ensuring the refrigerant operating pressure of the refrigeration system and guaranteeing safe and reliable system operation.

[0054] This embodiment provides a water-cooling system for a cascade refrigeration system. The water-cooling system includes: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The first end of the cascade refrigeration system is connected to the first end of the water tower and the first solenoid valve. The first end of the three-way valve is connected to both the first and second solenoid valves. The second end of the three-way valve is connected to the second end of the water tower. The third end of the three-way valve is connected to the water pump, which is also connected to the second end of the cascade refrigeration system. The second solenoid valve is also connected to the tap water supply. The ambient temperature detection unit detects the ambient temperature. The cooling water temperature... A temperature detection unit is installed at the second end of the water tower to detect the temperature of the cooling water in the water tower; a pressure detection unit is installed in the cascade refrigeration system to detect the pressure parameters of the cascade refrigeration system; the control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit, respectively; the control unit is configured to: acquire the target inlet water temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters; and control the opening or closing of the first solenoid valve or the second solenoid valve according to the preset conditions satisfied by the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve. Therefore, by setting up a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit, the system can detect and acquire in real time the target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters. Based on the real-time acquired target inlet temperature of the cooling water entering the cascade refrigeration system, the system can determine the preset conditions that need to be met and control the opening or closing of the first or second solenoid valve to adjust the opening of the three-way valve, so that the temperature of the cooling water entering the cascade refrigeration system is controlled within a reasonable range, thereby controlling the operating pressure of the system within a reasonable range and ensuring the safe and reliable operation of the system.

[0055] Figure 2 This is a schematic diagram of the water-cooled system of another cascade refrigeration system provided in an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 2The control unit 200 is further configured to: determine whether a first preset condition is met based on the target inlet water temperature, ambient temperature, and the temperature of the cooling water in the water tower; if met, control the first solenoid valve S1 to open and the second solenoid valve S2 to close; or, acquire the first opening degree of the three-way valve S3 when the first solenoid valve S1 is open; and determine whether a second preset condition is met based on the target inlet water temperature, ambient temperature, the temperature and pressure parameters of the cooling water in the water tower, and the first opening degree; if met, control the second solenoid valve to open and the first solenoid valve S1 to close, and calculate the second opening degree of the three-way valve S3 when the second solenoid valve S2 is open.

[0056] When the first solenoid valve S1 is open and the second solenoid valve S2 is closed, the water inlet at the first end of the three-way valve S3 is supplied by the first solenoid valve S1, and the water inlet at the second end of the three-way valve S3 is supplied by the water tower ST.

[0057] When the second solenoid valve S2 is open and the first solenoid valve S1 is closed, the water inlet at the first end of the three-way valve S3 is supplied by the second solenoid valve S2, and the water inlet at the second end of the three-way valve S3 is supplied by the water tower ST.

[0058] The first opening degree of the three-way valve S3 when the first solenoid valve S1 is open refers to the real-time opening degree value of the three-way valve S3 when the first solenoid valve S1 is open and the second solenoid valve S2 is closed. The first opening degree value is calculated by the control unit.

[0059] The second opening degree of the three-way valve S3 when the second solenoid valve S2 is open refers to the real-time opening degree value of the three-way valve S3 when the second solenoid valve S2 is open and the first solenoid valve S1 is closed. The second opening degree is calculated by the control unit.

[0060] Optionally, the first preset condition is: whether the ambient temperature is lower than the preset ambient temperature, or whether the temperature of the cooling water in the water tower is lower than the difference between the target inlet water temperature and the preset temperature error.

[0061] The specific value of the preset ambient temperature can be set according to the actual situation, and no specific limit is made here.

[0062] For example, the preset temperature error can be 5, and the specific value can be set according to the actual situation. No specific limit is set here.

[0063] The first preset condition is the condition for the first solenoid valve S1 to open, namely, the ambient temperature is less than the preset ambient temperature, or the temperature of the cooling water in the water tower is less than the difference between the target inlet water temperature and the preset temperature error. When either of these two conditions is met, the control unit 200 controls the first solenoid valve S1 to open.

[0064] Optionally, continue to refer to Figure 2The water cooling system of the cascade cooling system also includes an outlet water temperature detection unit T1, which is located at the first end of the cascade cooling system 100 and electrically connected to the control unit 200, for detecting the outlet water temperature of the cooling water output from the cascade cooling system 100.

[0065] The formula for calculating the first opening degree is as follows:

[0066]

[0067] Where A is the first opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T is the temperature of the cooling water in the water tower, TS is the target inlet water temperature, and K is the opening degree correction coefficient.

[0068] The outlet water temperature detection unit T1 is located at the first end of the cascade cooling system 100 and is electrically connected to the control unit 200. The outlet water temperature detection unit T1 is used to detect and acquire the outlet water temperature of the cooling water output by the cascade cooling system 100 in real time and send it to the control unit 200. The outlet water temperature detection unit T1 can be a temperature sensor.

[0069] Figure 3 This is a schematic diagram of the fully open structure of a water-cooled system of a cascade refrigeration system provided in an embodiment of the present invention. Optionally, refer to... Figure 2 and Figure 3 The pressure detection unit P0 includes a first pressure detection unit P1, which is located on the low-temperature side of the cascade refrigeration system and electrically connected to the control unit, for detecting the pressure at the outlet of the evaporator on the low-temperature side; the control unit 200 is also configured to: when the pressure at the outlet of the evaporator on the low-temperature side is a first preset pressure, and the temperature of the cooling water in the water tower is less than the sum of the error between the target inlet water temperature and the preset temperature, control the first solenoid valve S1 to open, the three-way valve S3 to fully open, and the second solenoid valve S2 to close.

[0070] The cascade refrigeration system includes a high-temperature R404A system and a low-temperature R23 system. The high-temperature R404A system contains a compressor and an evaporator, while the low-temperature R23 system contains both a compressor and an evaporator. A first pressure detection unit P1 is located at the evaporator outlet on the low-temperature side of the cascade refrigeration system and is electrically connected to the control unit 200. The first pressure detection unit P1 is used to monitor the pressure at the low-temperature evaporator outlet in real time and send the data to the control unit 200.

[0071] The first pressure detection unit P1 can be a pressure sensor. For example, the first preset pressure is 0. The first preset pressure can also be other values, which can be set according to actual conditions and are not specifically limited here.

[0072] Specifically, when the pressure at the outlet of the low-temperature evaporator is the first preset pressure, and the temperature of the cooling water in the water tower is less than the sum of the errors between the target inlet water temperature and the preset temperature, it indicates that the system pressure and temperature are too low, meeting the full-open condition. At this time, the first solenoid valve S1 is opened, the three-way valve S3 is 100% fully open, and the second solenoid valve S2 is closed. At this time, all the water entering the three-way valve S3 is supplied by the first solenoid valve S1 at its first end, while the second end of the three-way valve S3 is closed. That is, all the water flowing into the cascade refrigeration system from the three-way valve S3 for heat exchange comes from the water at the first solenoid valve S1 end. The water circulation direction when the three-way valve is fully open is as follows: Figure 3 As shown, the water flows from the first end of the cascade refrigeration system through the first solenoid valve S1, the three-way valve S3, and the water pump B0 to the second end of the cascade refrigeration system. This allows the temperature of the cooling water in the system to be controlled within a reasonable range, thereby ensuring the safe and reliable operation of the system.

[0073] Optionally, continue to refer to Figure 2 The pressure detection unit P0 also includes a second pressure detection unit P2, which is located on the high-temperature side of the cascade refrigeration system and electrically connected to the control unit 200. It is used to detect the discharge pressure of the high-temperature side compressor. The second preset condition is: the ambient temperature is greater than or equal to the preset ambient temperature, the first opening degree is less than the preset opening degree, the temperature of the cooling water in the water tower is greater than the sum of the error between the target inlet water temperature and the preset temperature, and the discharge pressure of the high-temperature side compressor is greater than or equal to the second preset pressure.

[0074] The second pressure detection unit P2 is located at the compressor on the high-temperature side of the cascade refrigeration system and is electrically connected to the control unit 200. The second pressure detection unit P2 is used to detect the discharge pressure of the high-temperature side compressor in real time and send it to the control unit 200.

[0075] The second pressure detection unit P2 can be a pressure sensor.

[0076] For example, the preset opening can be 5%. In addition, the preset opening can also be other values, which can be set according to the actual situation.

[0077] For example, the second preset pressure can be 2 MPa. Alternatively, the second preset pressure can be other values, which can be set according to actual conditions and are not specifically limited here.

[0078] Optionally, continue to refer to Figure 2The water cooling system of the cascade refrigeration system further includes: an outlet water temperature detection unit T1, which is located at the first end of the cascade refrigeration system and electrically connected to the control unit 200, for detecting the outlet water temperature of the cooling water output from the cascade refrigeration system; an inlet water temperature detection unit T2, which is located at the second end of the cascade refrigeration system and electrically connected to the control unit 200, for detecting the inlet water temperature of the cooling water entering the cascade refrigeration system; and a tap water temperature detection unit T3, which is connected to the tap water end ZL and electrically connected to the control unit 200, for detecting the temperature of the tap water.

[0079] The formula for calculating the second opening is:

[0080]

[0081] Where B is the second opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T is the inlet temperature of the cooling water entering the cascade refrigeration system, T3 is the temperature of the tap water, and K is the opening degree correction coefficient.

[0082] Among them, the outlet water temperature detection unit T1 and the tap water temperature detection unit T3 can be temperature sensors.

[0083] Figure 4 This is a schematic diagram of the fully open structure of a water-cooled system in another cascade refrigeration system provided in this embodiment of the invention. Optionally, the control unit 200 is further configured to: control the second solenoid valve S2 to open, the three-way valve S3 to fully open, and the first solenoid valve S1 to close when the exhaust pressure of the compressor on the high-temperature side is a second preset pressure, and the temperature of the cooling water in the water tower is greater than the sum of the errors between the target inlet water temperature and the preset temperature.

[0084] For example, the second preset pressure can be 2 MPa. Alternatively, the second preset pressure can be other values, which can be set according to actual conditions and are not specifically limited here.

[0085] Specifically, when the discharge pressure of the high-temperature side compressor is the second preset pressure, and the temperature T0 of the cooling water in the water tower is greater than the sum of the errors between the target inlet water temperature TS and the preset temperature, it indicates that the system pressure and temperature are too high, meeting the full-open condition. At this time, the second solenoid valve S2 is opened, the three-way valve S3 is 100% fully open, and the first solenoid valve S1 is closed. At this time, the water entering the three-way valve S3 is entirely supplied by the second solenoid valve S2 at its first end, and the second end of the three-way valve S2 is closed. That is, the water flowing into the cascade refrigeration system from the three-way valve S3 for heat exchange all comes from the tap water at the second solenoid valve S2 end. The water flow direction when the three-way valve is fully open is as follows: Figure 4As shown, the water flows from the tap water end to the second solenoid valve S2, then through the three-way valve S3 and the water pump B0 to the second end of the cascade refrigeration system. The cooling water output from the first end of the cascade refrigeration system is directly stored in the water tower ST. This allows the temperature of the cooling water in the system to be controlled within a reasonable range, thereby ensuring the refrigerant operating pressure of the refrigeration system and guaranteeing the safe and reliable operation of the system.

[0086] Optionally, the opening correction factor is determined by a preset ambient temperature judgment range and opening correction factor comparison table.

[0087] The table showing the comparison between the preset ambient temperature judgment range and the opening correction coefficient is shown in Table 1. When the ambient temperature TH is known, the corresponding opening correction coefficient can be determined according to the table showing the comparison between the preset ambient temperature judgment range and the opening correction coefficient.

[0088] Table 1 Comparison of Preset Ambient Temperature Judgment Range and Opening Correction Coefficient

[0089]

[0090] For example, the following description is based on a preset ambient temperature of 35°C, a preset temperature error of 5°C, a preset opening degree of 5%, a first preset pressure of 0, and a second preset pressure of 2MPa (the same applies below, and will not be repeated).

[0091] For example, assume the ambient temperature TH is 10℃, the target inlet water temperature TS is 25℃, the outlet water temperature T1 of the cooling water output from the cascade refrigeration system is 30℃, and the cooling water temperature T0 of the water tower is 15℃. Since the ambient temperature is 10 degrees, the first preset condition is met. Therefore, the first solenoid valve S1 is opened, and the second solenoid valve S2 is closed. According to the formula for calculating the first opening degree, the first opening degree A can be calculated as: A = {(30-15) / 25}*{(25-15) / 10*1} = 66%. At this time, the first end of the three-way valve S1 provides 66% water (i.e., provided by the first solenoid valve S1 end), which mixes with the second end providing 34% cooling water (provided by the cooling water in the water tower ST) and re-enters the cascade refrigeration system for heat exchange.

[0092] For example, assuming the ambient temperature TH is 35℃, the target inlet water temperature is 25℃, the outlet temperature T1 of the cooling water output from the cascade refrigeration system is 35℃, the cooling water temperature T0 of the water tower is 28℃, and the tap water temperature T3 is 18℃, then the first solenoid valve S1 is closed, and the second solenoid valve S2 is open, with the second opening degree B being: B = {(35-18) / 28}*{(35-28) / 25*1.2} = 14%. At this time, the first end of the three-way valve S1 provides 14% of the 18℃ tap water (i.e., provided by the second solenoid valve S2), which mixes with the second end providing 86.4% of the cooling water (provided by the cooling water in the water tower ST) and re-enters the cascade refrigeration system for heat exchange.

[0093] For example, assuming the ambient temperature TH is 20℃, the target inlet water temperature is 25℃, the outlet temperature T1 of the cooling water output from the cascade refrigeration system is 23℃, the cooling water temperature T0 of the water tower is 18℃, and the pressure detected by the first pressure detection unit is 2.1MPa, then the first solenoid valve opens and the second solenoid valve S2 closes, with the first opening degree A being: A={(23-18) / 25}*{(25-18) / 20*1.1+1}=26.4%. At this time, the first end of the three-way valve S1 provides 26.4% water (i.e., provided by the first solenoid valve S1 end), which mixes with the second end providing 73.6% cooling water (provided by the cooling water in the water tower ST) and re-enters the cascade refrigeration system for heat exchange.

[0094] In the technical solution of this embodiment, the implementation process of the water cooling system of the cascade refrigeration system is as follows: (Refer to...) Figure 2By setting up a first solenoid valve S1, a second solenoid valve S2, a three-way valve S3, an ambient temperature detection unit TH, a cooling water temperature detection unit T0, an outlet water temperature detection unit T1, an inlet water temperature detection unit T2, a tap water temperature detection unit T3, a first pressure detection unit P1, and a second pressure detection unit P2, the system can detect and acquire in real time the target inlet water temperature, ambient temperature, cooling water temperature of the water tower, inlet water temperature, outlet water temperature, tap water temperature, pressure parameters, and target inlet water temperature of the cooling water entering the cascade refrigeration system. Furthermore, based on real-time data such as the target inlet temperature of the cooling water entering the cascade refrigeration system, ambient temperature, cooling water temperature of the water tower, inlet temperature, outlet temperature, tap water temperature, pressure parameters, and the target inlet temperature, the specific preset conditions that must be met are determined (whether the first preset condition, the second preset condition, or the fully open condition is met). The system then controls the first solenoid valve S1 or the second solenoid valve S2 to open or close, thereby adjusting the opening degree of the three-way valve. This ensures that the opening degree of the three-way valve is set at a reasonable value, thus controlling the temperature of the cooling water entering the cascade refrigeration system within a reasonable range. This solves the problems of unreliable and unsafe system operation caused by excessively high or low cooling water temperatures in existing technologies, thereby ensuring the safe and reliable operation of the system.

[0095] Figure 5 This is a schematic diagram of the structure of a water-cooled system according to an embodiment of the cascade refrigeration system provided in this invention. For example, refer to... Figure 5 The cascade refrigeration system comprises a high-temperature R404A system and a low-temperature R23 system. The high-temperature R404A system includes a high-temperature compressor, a second pressure detection unit P2, a solenoid valve, an R404 evaporator, a cooling fan, an oil separator, pressure gauges, and a flow control valve. The low-temperature R23 system includes a low-temperature compressor, an R23 evaporator, a solenoid valve, a first voltage detection unit P1, a thermostatic expansion valve, a flow control valve, and an expansion tank. (Reference) Figure 5 The water cooling system includes a first solenoid valve S1, a second solenoid valve S2, a three-way valve S3, a water pump B0, a water tower ST, an outlet water temperature detection unit T1, an inlet water temperature detection unit T2, a tap water temperature detection unit T3, an ambient temperature detection unit TH, a first ball valve SF1, a second ball valve SF2, a filter G0, a temperature and pressure gauge, and a water pressure protection device B1. Its specific connection structure is as follows: Figure 5 As shown.

[0096] This invention also provides an environmental test chamber, which includes the water cooling system of the cascade refrigeration system provided in any embodiment of this invention.

[0097] The environmental test chamber consists of a chamber, a refrigeration system (such as a cascade refrigeration system), a water-cooling system for the cascade refrigeration system, and a control system. The chamber is mainly composed of thermal insulation materials. The control system mainly consists of a touch screen, a PLC and its expansion modules, and temperature sensors. The refrigeration system mainly consists of a compressor, a condenser, an evaporator and its fan, and an electronic expansion valve (or other adjustable throttling elements).

[0098] Figure 6 This is a flowchart illustrating a control method for a water-cooled system of a cascade refrigeration system provided in an embodiment of the present invention. The present invention also provides a control method for a water-cooled system of a cascade refrigeration system, see reference [link to documentation]. Figure 6 The method includes the following steps:

[0099] S110: Obtain the target inlet water temperature, ambient temperature, and temperature and pressure parameters of the cooling water entering the cascade refrigeration system.

[0100] S120: Control the opening or closing of the first or second solenoid valve according to the preset conditions met by the target inlet water temperature, ambient temperature, cooling water temperature and pressure parameters of the water tower, so as to adjust the opening degree of the three-way valve.

[0101] The water cooling system of the cascade refrigeration system includes: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The first end of the cascade refrigeration system is connected to the first end of the water tower and the first solenoid valve. The first end of the three-way valve is connected to both the first and second solenoid valves. The second end of the three-way valve is connected to the second end of the water tower. The third end of the three-way valve is connected to the water pump, which is also connected to the second end of the cascade refrigeration system. The second solenoid valve is also connected to the tap water supply. The ambient temperature detection unit detects the ambient temperature. The cooling water temperature detection unit is located at the second end of the water tower and detects the temperature of the cooling water in the water tower. The pressure detection unit is located within the cascade refrigeration system and detects the pressure parameters of the cascade refrigeration system. The control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit.

[0102] The technical method of this embodiment provides a control method for the water cooling system of a cascade refrigeration system. The control method includes: acquiring the target inlet water temperature, ambient temperature, and temperature and pressure parameters of the cooling water entering the cascade refrigeration system; and controlling the opening or closing of a first solenoid valve or a second solenoid valve according to preset conditions satisfied by the target inlet water temperature, ambient temperature, and temperature and pressure parameters of the cooling water in the water tower, so as to adjust the opening degree of the three-way valve. Therefore, by setting up a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit, the system can detect and acquire in real time the target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters. Based on the real-time acquired target inlet temperature of the cooling water entering the cascade refrigeration system, the system can determine the preset conditions that need to be met and control the opening or closing of the first or second solenoid valve to adjust the opening of the three-way valve, so that the temperature of the cooling water entering the cascade refrigeration system is controlled within a reasonable range, thereby controlling the operating pressure of the system within a reasonable range and ensuring the safe and reliable operation of the system.

[0103] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0104] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A water-cooling system for a cascade refrigeration system, characterized in that, include: The system includes a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The cascade refrigeration system is configured such that its first end is connected to both the first end of the water tower and the first solenoid valve; its first end is connected to both the first and second solenoid valves; its second end is connected to the second end of the water tower; its third end is connected to the water pump; the water pump is also connected to the second end of the cascade refrigeration system; and the second solenoid valve is also connected to the tap water supply. An ambient temperature detection unit is used to detect the ambient temperature. A cooling water temperature detection unit is located at the second end of the water tower and is used to detect the temperature of the cooling water in the water tower. A pressure detection unit is located within the cascade refrigeration system and is used to detect the pressure parameters of the cascade refrigeration system. The control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit, respectively. The control unit is configured to: acquire the target inlet water temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters; and control the opening or closing of the first solenoid valve or the second solenoid valve according to preset conditions satisfied by the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve.

2. The water-cooling system of the cascade refrigeration system according to claim 1, characterized in that, The control unit is also configured to: The system determines whether the first preset condition is met based on the target inlet water temperature, the ambient temperature, and the cooling water temperature of the water tower. If the condition is met, the system controls the first solenoid valve to open and the second solenoid valve to close. Alternatively, obtain the first opening degree of the three-way valve when the first solenoid valve is open; and determine whether the second preset condition is met based on the target inlet water temperature, the ambient temperature, the temperature of the cooling water in the water tower, the pressure parameter, and the first opening degree. If the condition is met, control the second solenoid valve to open and the first solenoid valve to close, and calculate the second opening degree of the three-way valve when the second solenoid valve is open.

3. The water-cooling system of the cascade refrigeration system according to claim 2, characterized in that, The first preset condition is: whether the ambient temperature is less than the preset ambient temperature, or whether the temperature of the cooling water in the water tower is less than the difference between the target inlet water temperature and the preset temperature error.

4. The water-cooling system of the cascade refrigeration system according to claim 3, characterized in that, Also includes: An outlet water temperature detection unit is installed at the first end of the cascade refrigeration system and is electrically connected to the control unit, for detecting the outlet water temperature of the cooling water output from the cascade refrigeration system; The formula for calculating the first opening is: Where A is the first opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T0 is the temperature of the cooling water in the water tower, TS is the target inlet water temperature, and K is the opening degree correction coefficient.

5. The water-cooling system of the cascade refrigeration system according to claim 3, characterized in that, The pressure detection unit includes a first pressure detection unit, which is disposed on the low-temperature side of the cascade refrigeration system and electrically connected to the control unit, for detecting the pressure at the outlet of the evaporator on the low-temperature side; The control unit is further configured to: when the pressure at the outlet of the low-temperature side evaporator is a first preset pressure, and the temperature of the cooling water in the water tower is less than the sum of the errors between the target inlet water temperature and the preset temperature, control the first solenoid valve to open, the three-way valve to fully open, and the second solenoid valve to close.

6. The water-cooling system of the cascade refrigeration system according to claim 2, characterized in that, The pressure detection unit further includes a second pressure detection unit, which is located on the high-temperature side of the cascade refrigeration system and electrically connected to the control unit, for detecting the discharge pressure of the compressor on the high-temperature side; The second preset condition is: the ambient temperature is greater than or equal to the preset ambient temperature, the first opening degree is less than the preset opening degree, the temperature of the cooling water in the water tower is greater than the sum of the errors between the target inlet water temperature and the preset temperature, and the exhaust pressure of the high-temperature side compressor is greater than or equal to the second preset pressure.

7. The water-cooling system of the cascade refrigeration system according to claim 6, characterized in that, Also includes: An outlet water temperature detection unit is installed at the first end of the cascade refrigeration system and is electrically connected to the control unit, for detecting the outlet water temperature of the cooling water output from the cascade refrigeration system; An inlet water temperature detection unit is installed at the second end of the cascade refrigeration system and is electrically connected to the control unit. It is used to detect the inlet water temperature of the cooling water entering the cascade refrigeration system. The tap water temperature detection unit is connected to the tap water terminal and electrically connected to the control unit, and is used to detect the temperature of the tap water. The formula for calculating the second opening is: Wherein, B is the second opening degree, T1 is the outlet temperature of the cooling water output from the cascade refrigeration system, T2 is the inlet temperature of the cooling water entering the cascade refrigeration system, T3 is the temperature of the tap water, and K is the opening degree correction coefficient.

8. The water-cooling system of the cascade refrigeration system according to claim 7, characterized in that, The control unit is further configured to: when the exhaust pressure of the high-temperature side compressor is a second preset pressure, and the temperature of the cooling water in the water tower is greater than the sum of the error between the target inlet water temperature and the preset temperature, control the second solenoid valve to open, the three-way valve to fully open, and the first solenoid valve to close.

9. An environmental test chamber, characterized in that, Water cooling systems including the cascade refrigeration systems as described in any one of claims 1-8.

10. A control method for a water-cooled system in a cascade refrigeration system, characterized in that, A water-cooling system for use in a cascade refrigeration system includes: a first solenoid valve, a second solenoid valve, a three-way valve, a water pump, a water tower, an ambient temperature detection unit, a cooling water temperature detection unit, a pressure detection unit, and a control unit. The first end of the cascade refrigeration system is connected to the first end of the water tower and the first solenoid valve. The first end of the three-way valve is connected to both the first and second solenoid valves. The second end of the three-way valve is connected to the second end of the water tower. The third end of the three-way valve is connected to the water pump. The water pump is also connected to the second end of the cascade refrigeration system. The second solenoid valve is also connected to a tap water supply. The ambient temperature detection unit detects the ambient temperature. The cooling water temperature detection unit is located at the second end of the water tower and detects the temperature of the cooling water in the water tower. The pressure detection unit is located in the cascade refrigeration system and detects the pressure parameters of the cascade refrigeration system. The control unit is electrically connected to the first solenoid valve, the second solenoid valve, the three-way valve, the ambient temperature detection unit, the cooling water temperature detection unit, and the pressure detection unit. The control method includes: The target inlet temperature of the cooling water entering the cascade refrigeration system, the ambient temperature, the temperature of the cooling water in the water tower, and the pressure parameters are obtained. The opening or closing of the first or second solenoid valve is controlled according to the preset conditions satisfied by the target inlet water temperature, the ambient temperature, the cooling water temperature of the water tower, and the pressure parameters, so as to adjust the opening degree of the three-way valve.

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