Energy-saving type high and low temperature environment test box refrigerating system and control method thereof

Abstract

The invention provides an energy-saving type high and low temperature environment test box refrigerating system and a control method thereof, and relates to the technical field of refrigerating systems. The system comprises a heater, an evaporator, a two-stage piston compressor, a scroll compressor, a heat exchanger, a low-temperature throttling valve and a high-temperature throttling valve. The heater is used for heating a test load; the evaporator is used for cooling the test load; when the required temperature of the test load is within a preset low-temperature interval, a two-stage piston compressor is adopted for refrigeration, a frequency converter is arranged, and 45%-100% of cold output of the two-stage piston compressor is achieved; when the required temperature of the test load is within a preset high-temperature interval, the scroll compressor is adopted for refrigeration, and 20%-100% cold output of the scroll compressor is achieved; a heater is adopted for heating operation, and a controller is selected for adjusting energy by 0-100%. The purpose of energy-saving operation is achieved through high-temperature and low-temperature partitioned operation and the mode that the output of the compressor and the output of the heater are adjustable.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration systems, and in particular to an energy-saving high and low temperature environment test chamber refrigeration system and a control method thereof. Background Art

[0002] In the manufacturing process of semiconductor chips and lithium batteries, environmental adaptability testing is a must-pass test step to verify the stability and reliability of the product. Due to the long testing time, an energy-saving high and low temperature environmental test chamber can significantly reduce the production cost of the product and relieve the power pressure of the factory.

[0003] At present, when the high and low temperature test chamber is working, the refrigeration system and the heating system work simultaneously to achieve dynamic heat balance to meet the requirements of ambient temperature simulation. However, the output of the compressor in the refrigeration system and the heater in the heating system is a fixed value and cannot be adjusted. In order to achieve the stability of the target temperature, a large amount of energy will be consumed for heat balance. Long-term operation of the unit will consume large power consumption and high operating costs. Summary of the invention

[0004] The purpose of the present invention includes providing an energy-saving high and low temperature environment test chamber refrigeration system and a control method thereof, which can achieve the purpose of energy-saving operation by high and low temperature zone operation and adjustable compressor and heater output.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides an energy-saving high and low temperature environment test chamber refrigeration system, the system comprising a heater, an evaporator, a two-stage piston compressor, a scroll compressor, a heat exchanger, a low temperature throttle valve and a high temperature throttle valve;

[0007] The heater is used to heat the test load and the evaporator is used to cool the test load;

[0008] The two-stage piston compressor includes an inlet A1 and an outlet B1 that are interconnected, and also includes an inlet A2 and an outlet B2 that are interconnected; the heat exchanger includes an inlet A3 and an outlet B3 that are interconnected, the inlet A3 is used to introduce cooling water, and the outlet B3 is used to output cooling water, and also includes an inlet A4 and an outlet B4 that are interconnected;

[0009] The outlet of the evaporator is connected to the inlet A1 of the two-stage piston compressor and the inlet of the scroll compressor, the outlet B1 of the two-stage piston compressor and the outlet of the scroll compressor are both connected to the inlet A4 of the heat exchanger, the outlet B4 of the heat exchanger is connected to the inlet A2 of the two-stage piston compressor, and the outlet B2 of the two-stage piston compressor is connected to the inlet of the evaporator through a low-temperature throttle valve;

[0010] The outlet B4 of the heat exchanger is also connected to the inlet of the evaporator through a high temperature throttle valve.

[0011] In an optional embodiment, the system further comprises a four-way valve, the four-way valve comprising an inlet A5 and an outlet B5 connected to each other, and an inlet A6 and an outlet B6 connected to each other; the outlet of the evaporator is connected to the inlet A1 of the two-stage piston compressor and the inlet of the scroll compressor through the inlet A5 and the outlet B5;

[0012] The system also includes a gas-liquid separator, and the outlet B1 of the two-stage piston compressor and the outlet of the scroll compressor are both connected to the inlet A4 of the heat exchanger through the gas-liquid separator;

[0013] The system also includes a return air low temperature protection branch, on which a return air low temperature solenoid valve is provided, one end of the return air low temperature protection branch is connected to the outlet of the gas-liquid separator, and the other end of the return air low temperature protection branch is connected to the inlet A4 of the heat exchanger through the inlet A6 and outlet B6 of the four-way valve.

[0014] In an optional embodiment, the system also includes a low-temperature energy regulating branch, on which a low-temperature energy solenoid valve and a low-temperature energy regulating valve are provided, one end of the low-temperature energy regulating branch is connected to the outlet of the gas-liquid separator, and the other end of the low-temperature energy regulating branch is connected to the outlet of the low-temperature throttle valve.

[0015] In an optional embodiment, the system also includes a high-temperature energy regulating branch, on which a high-temperature energy solenoid valve and a high-temperature energy regulating valve are provided, one end of the high-temperature energy regulating branch is connected to the outlet of the gas-liquid separator, and the other end of the high-temperature energy regulating branch is connected to the outlet of the high-temperature throttle valve.

[0016] In a second aspect, the present invention provides a control method for an energy-saving high and low temperature environment test chamber refrigeration system, the control method is used to control the system of the aforementioned embodiment, and the control method comprises the following steps:

[0017] S1: When the test load demand temperature is within the preset low temperature range, a two-stage piston compressor is used for refrigeration, and a frequency converter is provided to achieve a cooling output of 45%-100% of the two-stage piston compressor;

[0018] S2: When the required temperature of the test load is within the preset high temperature range, the scroll compressor is used for refrigeration to achieve a cooling output of 20%-100% of the scroll compressor;

[0019] S3: Use the heater for heating operation and use the controller to adjust the energy from 0 to 100%.

[0020] In an optional embodiment, the control method further comprises the following steps:

[0021] S4: When the two-stage piston compressor or the scroll compressor is at the lowest output condition, the output of the two-stage piston compressor or the scroll compressor is controlled by an energy regulating valve to achieve 10%-100% energy regulation.

[0022] In an optional embodiment, when system refrigeration is required, the control method further includes the following steps:

[0023] Execute S1 or S2 to meet different required temperatures of the test load;

[0024] Execute S4 to continue reducing the output of the two-stage piston compressor or the scroll compressor to maintain the required temperature;

[0025] After the test load is turned on, the output of the two-stage piston compressor or scroll compressor is gradually increased to maintain the required temperature.

[0026] In an optional embodiment, when the system needs to heat, the control method further includes the following steps:

[0027] According to the required temperature, the power of the heater is controlled to increase the temperature of the test load;

[0028] When the difference between the required temperature and the temperature of the test load is less than a threshold, the power of the heater starts to be reduced to maintain the temperature of the test load at the required temperature;

[0029] After the test load is turned on, S2 is executed to perform heat balance to maintain the required temperature.

[0030] In an optional implementation, after the test load is turned on, S2 is executed to perform heat balance to maintain the required temperature, including:

[0031] Control the scroll compressor to be at 20%-40% cooling output.

[0032] In an optional embodiment, the preset low temperature range is -40°C to -15°C, and the preset high temperature range is -15°C to 150°C.

[0033] The beneficial effects of the energy-saving high and low temperature environment test chamber refrigeration system and control method thereof provided by the embodiment of the present invention include:

[0034] By adopting the temperature zoning method, a two-stage piston compressor is used for refrigeration in the preset low temperature range (-40℃~-15℃), and a frequency converter is equipped to achieve a cooling output of 45%-100%. The power consumption of the two-stage piston compressor can be reduced to 45% of the rated power. In the preset high temperature range (-15℃~150℃), a scroll compressor is used for refrigeration to achieve a cooling output of 20%-100%, and the power consumption of the scroll compressor can be reduced to 20% of the rated power. In the heating state (set value ≥25℃), a heater is used for heating to achieve an output of 0-100%. When maintaining a stable temperature, a smaller cooling or heating output is used to balance the heat. When the system is running for a long time, a low power consumption state is maintained to achieve energy saving and reduce the cost of use. It can be widely used in the fields of semiconductor chip aging test, lithium battery performance test, etc., providing new technical means for the development of related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic diagram of the operation of the energy-saving high and low temperature environment test chamber refrigeration system in a preset low temperature range provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the operation of the energy-saving high and low temperature environment test chamber refrigeration system in a preset high temperature range provided by an embodiment of the present invention;

[0038] Figure 3 for Figure 1 and Figure 2 Explanation of the lines and symbols.

[0039] Icons: 1-heater; 2-evaporator; 3-four-way valve; 4-two-stage piston compressor; 5-scroll compressor; 6-gas-liquid separator; 7-heat exchanger; 8-liquid reservoir; 9-drying filter; 10-sight glass; 11-low-temperature solenoid valve; 12-low-temperature throttle valve; 13-high-temperature solenoid valve; 14-high-temperature throttle valve; 15-return air low-temperature solenoid valve; 16-low-temperature energy solenoid valve; 17-low-temperature energy regulating valve; 18-high-temperature energy solenoid valve; 19-high-temperature energy regulating valve; 20-check valve; 21-water filter; 22-test load. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0044] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0045] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0046] Please refer to Figure 1 and Figure 2 The present embodiment provides an energy-saving high and low temperature environment test chamber refrigeration system (hereinafter referred to as: system), the system includes a heater 1, an evaporator 2, a two-stage piston compressor 4, a scroll compressor 5, a heat exchanger 7, a low-temperature throttle valve 12, a high-temperature throttle valve 14, a four-way valve 3, a gas-liquid separator 6, a liquid storage tank 8, a drying filter 9, a sight glass 10, a water filter 21 and a one-way valve 20.

[0047] The heater 1 and the evaporator 2 are used to be installed beside the test load 22, the heater 1 is used to heat the test load 22, and the evaporator 2 is used to cool the test load 22. The test load 22 can be a chip, a lithium battery, etc.

[0048] Preferably, the heater 1 and the evaporator 2 are installed in the same frame to form a test box, and the test load 22 can be directly placed in the test box, and the test box is used to perform a temperature test on the test load 22 for cooling and heating. Other devices and pipelines that control the evaporator 2 in the system (including a two-stage piston compressor 4, a scroll compressor 5, a heat exchanger 7, etc.) can be combined into one to form a refrigeration main unit. The refrigeration main unit and the test box are then connected by a detachable pipe, and a metal flexible pipe can also be provided on the detachable pipe to adjust and offset the error generated when the test box is connected to the refrigeration main unit. At the same time, the vibration of the refrigeration main unit during operation can be prevented from being transmitted to the test box.

[0049] The two-stage piston compressor 4 includes an inlet A1 and an outlet B1 which are connected to each other, and each of the inlet A1 and the outlet B1 is provided with a one-way valve 20. The two-stage piston compressor 4 also includes an inlet A2 and an outlet B2 which are connected to each other, and an electromagnetic valve is provided at the outlet B2.

[0050] The heat exchanger 7 includes an inlet A3 and an outlet B3 which are connected to each other. A one-way valve 20 and a water filter 21 are provided at the inlet A3 for introducing cooling water. A one-way valve 20 is provided at the outlet B3 for outputting cooling water. The heat exchanger 7 also includes an inlet A4 and an outlet B4 which are connected to each other. A liquid storage 8, a drying filter 9 and a sight glass 10 are provided at the outlet B4 of the heat exchanger 7 in sequence.

[0051] The four-way valve 3 includes an inlet A5 and an outlet B5 that are connected to each other, and also includes an inlet A6 and an outlet B6 that are connected to each other.

[0052] The outlet of the evaporator 2 is connected to the inlet A1 of the two-stage piston compressor 4 and the inlet of the scroll compressor 5 through the inlet A5 and the outlet B5 of the four-way valve 3. The outlet B1 of the two-stage piston compressor 4 and the outlet of the scroll compressor 5 are both connected to the inlet A4 of the heat exchanger 7 through the gas-liquid separator 6. The outlet B4 of the heat exchanger 7 is also connected to the inlet of the evaporator 2 through the high-temperature throttle valve 14. Among them, the inlet and outlet of the scroll compressor 5 are both provided with a one-way valve 20. The pressure-taking pipe of the high-temperature throttle valve 14 is connected to the outlet of the evaporator 2. A high-temperature solenoid valve 13 is also provided on the pipeline from the outlet B4 of the heat exchanger 7 to the high-temperature throttle valve 14.

[0053] The outlet B2 of the two-stage piston compressor 4 is connected to the inlet of the evaporator 2 through the low-temperature throttle valve 12. A low-temperature solenoid valve 11 is also provided between the outlet B2 of the two-stage piston compressor 4 and the low-temperature throttle valve 12. The low-temperature throttle valve 12 is connected to the inlet of the evaporator 2 through two parallel pipelines, and a one-way valve 20 is provided on both parallel pipelines. The pressure-taking pipe of the low-temperature throttle valve 12 is connected to the outlet of the evaporator 2.

[0054] The system also includes a return air low temperature protection branch, a low temperature energy regulating branch and a high temperature energy regulating branch.

[0055] It should be noted that the low temperature and high temperature in this embodiment are relative to each other, and there is no specific temperature requirement. For example, when the required temperature of the test load 22 is within the preset low temperature range, the low temperature throttle valve 12 and the low temperature solenoid valve 11 will be opened during the operation of the system, and the return air low temperature protection branch and the low temperature energy regulation branch will also be considered to be opened; when the required temperature of the test load 22 is within the preset high temperature range, the high temperature throttle valve 14 and the high temperature solenoid valve 13 will be opened during the operation of the system, and the high temperature energy regulation branch will also be considered to be opened.

[0056] Specifically, a return air low temperature solenoid valve 15 is provided on the return air low temperature protection branch, one end of the return air low temperature protection branch is connected to the outlet of the gas-liquid separator 6, and the other end of the return air low temperature protection branch is connected to the inlet A4 of the heat exchanger 7 through the inlet A6 and the outlet B6 of the four-way valve 3. A one-way valve 20 is provided on the pipeline from the outlet B6 of the four-way valve 3 to the inlet A4 of the heat exchanger 7.

[0057] The low-temperature energy regulating branch is provided with a low-temperature energy solenoid valve 16 and a low-temperature energy regulating valve 17, one end of the low-temperature energy regulating branch is connected to the outlet of the gas-liquid separator 6, and the other end of the low-temperature energy regulating branch is connected to the outlet of the low-temperature throttle valve 12. Among them, the pressure-taking pipe of the low-temperature energy regulating valve 17 is connected to the outlet of the evaporator 2.

[0058] The high temperature energy regulating branch is provided with a high temperature energy solenoid valve 18 and a high temperature energy regulating valve 19, one end of the high temperature energy regulating branch is connected to the outlet of the gas-liquid separator 6, and the other end of the high temperature energy regulating branch is connected to the outlet of the high temperature throttle valve 14. Among them, the pressure taking pipe of the high temperature energy regulating valve 19 is connected to the outlet of the evaporator 2.

[0059] This embodiment also provides a control method for the above system, and the main steps of the control method include:

[0060] S1: When the required temperature of the test load 22 is within the preset low temperature range, a two-stage piston compressor 4 is used for refrigeration, and a frequency converter is provided to achieve a cooling capacity output of 45%-100% of the two-stage piston compressor 4; wherein the preset low temperature range is -40°C to -15°C.

[0061] For details, please refer to Figure 1 and Figure 3, cooling water flows in from the inlet A3 of the heat exchanger 7 and flows out from the outlet B3 of the heat exchanger 7. The low-temperature and low-pressure gas flowing out of the outlet of the evaporator 2 passes through the inlet A5 and outlet B5 of the four-way valve 3 to the inlet A1 of the two-stage piston compressor 4, and then flows out from the outlet B1 of the two-stage piston compressor 4, and is converted into high-temperature and high-pressure gas, passes through the gas-liquid separator 6 to the inlet A4 of the heat exchanger 7, and then flows out from the outlet B4 of the heat exchanger 7, and is converted into medium-temperature and high-pressure liquid, and then passes through the liquid storage 8, the drying filter 9 and the sight glass 10, and then passes through the inlet A2 and outlet B2 of the two-stage piston compressor 4 and the low-temperature solenoid valve 11, and reaches the low-temperature throttle valve 12, and is converted into low-temperature and low-pressure liquid, and returns to the inlet of the evaporator 2.

[0062] The return air low temperature solenoid valve 15 on the return air low temperature protection branch is opened when the return air temperature is lower than a threshold value.

[0063] S2: When the required temperature of the test load 22 is within the preset high temperature range, the scroll compressor 5 is used for refrigeration to achieve a cooling capacity output of 20%-100% of the scroll compressor 5; wherein the preset high temperature range is -15°C to 150°C.

[0064] For details, please refer to Figure 2 and Figure 3 , cooling water flows in from the inlet A3 of the heat exchanger 7 and flows out from the outlet B3 of the heat exchanger 7. The low-temperature and low-pressure gas flowing out of the outlet of the evaporator 2 passes through the inlet A5 and outlet B5 of the four-way valve 3 to reach the inlet of the scroll compressor 5, and then flows out from the outlet of the scroll compressor 5, and is converted into high-temperature and high-pressure gas, passes through the gas-liquid separator 6 to reach the inlet A4 of the heat exchanger 7, and then flows out from the outlet B4 of the heat exchanger 7, and is converted into medium-temperature and high-pressure liquid, and then passes through the liquid storage 8, the drying filter 9, the sight glass 10 and the high-temperature solenoid valve 13, reaches the high-temperature throttle valve 14, and is converted into low-temperature and low-pressure liquid, and returns to the inlet of the evaporator 2.

[0065] The return air low temperature solenoid valve 15 on the return air low temperature protection branch is opened when the return air temperature is lower than a threshold value.

[0066] S3: Heater 1 is used for heating operation, and a controller is selected to adjust the energy from 0 to 100%. The conditions for starting heater 1 can be set to include that the required temperature of the test load 22 is greater than or equal to 25°C.

[0067] S4: When the two-stage piston compressor 4 or the scroll compressor 5 is at the lowest output condition, the output of the two-stage piston compressor 4 or the scroll compressor 5 is controlled by an energy regulating valve to achieve 10%-100% energy regulation.

[0068] For details, please refer to Figure 1 and Figure 3When the two-stage piston compressor 4 is at the lowest output condition, the low-temperature energy solenoid valve 16 and the low-temperature energy regulating valve 17 on the low-temperature energy regulating branch are opened. Figure 2 and Figure 3 When the scroll compressor 5 is at the lowest output condition, the high-temperature energy solenoid valve 18 and the high-temperature energy regulating valve 19 on the high-temperature energy regulating branch are opened.

[0069] S1 to S4 do not have a strict sequence, but S1 to S3 are flexibly executed according to the required temperature of the test load 22, and S4 is automatically executed when the conditions are met. In this way, through the coordination of S1 to S4, the two-stage piston compressor 4 and the scroll compressor 5 can be maintained in a low power consumption state, achieving the purpose of energy saving and reducing the use cost.

[0070] When system cooling is required, the control method also includes the following steps: first, execute S1 or S2 to meet the different required temperatures of the test load 22; then, execute S4 to continue to reduce the output of the two-stage piston compressor 4 or the scroll compressor 5 to maintain the required temperature; finally, after the test load 22 is turned on, gradually increase the frequency to increase the output of the two-stage piston compressor 4 or the scroll compressor 5 to maintain the required temperature.

[0071] When the system needs to heat, the control method also includes the following steps: first, according to the required temperature, the power of the heater 1 is controlled to increase the temperature of the test load 22; then, when the difference between the required temperature and the temperature of the test load 22 is less than the threshold, the power of the heater 1 is reduced to maintain the temperature of the test load 22 at the required temperature; finally, after the test load 22 is turned on, S2 is executed, preferably controlling the scroll compressor 5 to be at a cooling output of 20%-40%, and performing heat balance to maintain the required temperature.

[0072] The beneficial effects of the energy-saving high and low temperature environment test chamber refrigeration system and control method thereof provided by the embodiment of the present invention include:

[0073] 1. By adopting the temperature zoning method, a two-stage piston compressor 4 is used for refrigeration in the preset low temperature range (-40℃~-15℃), and a frequency converter is equipped to achieve a cooling output of 45%-100%, and the power consumption of the two-stage piston compressor 4 can be reduced to 45% of the rated power. In the preset high temperature range (-15℃~150℃), a scroll compressor 5 is used for refrigeration to achieve a cooling output of 20%-100%, and the power consumption of the scroll compressor 5 can be reduced to 20% of the rated power. In the heating state (set value ≥25℃), a heater 1 is used for heating, which can achieve an output of 0-100%. When maintaining a stable temperature, a smaller cooling or heating output is used to balance the heat. Maintain a low power consumption state when the system is running for a long time to achieve the purpose of energy saving and reduce the cost of use.

[0074] 2. It can be widely used in the fields of semiconductor chip aging test, lithium battery performance test, etc., providing new technical means for the development of related fields;

[0075] 3. The system provided in this embodiment adopts a modular design method, in which the refrigeration main unit and the test box are designed and produced as independent modules, and the evaporator of the refrigeration main unit is independent of the test box. They are combined together through detachable pipes to achieve the function of separate transportation and assembly of the refrigeration main unit and the test box.

[0076] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An energy-saving high and low temperature environment test chamber refrigeration system, characterized in that: The system comprises a heater (1), an evaporator (2), a two-stage piston compressor (4), a scroll compressor (5), a heat exchanger (7), a low-temperature throttle valve (12) and a high-temperature throttle valve (14); The heater (1) is used to heat the test load (22), and the evaporator (2) is used to cool the test load (22); The two-stage piston compressor (4) comprises an inlet A1 and an outlet B1 which are interconnected, and also comprises an inlet A2 and an outlet B2 which are interconnected; the heat exchanger (7) comprises an inlet A3 and an outlet B3 which are interconnected, the inlet A3 is used for introducing cooling water, the outlet B3 is used for outputting cooling water, and also comprises an inlet A4 and an outlet B4 which are interconnected; The outlet of the evaporator (2) is connected to the inlet A1 of the two-stage piston compressor (4) and the inlet of the scroll compressor (5); the outlet B1 of the two-stage piston compressor (4) and the outlet of the scroll compressor (5) are both connected to the inlet A4 of the heat exchanger (7); the outlet B4 of the heat exchanger (7) is connected to the inlet A2 of the two-stage piston compressor (4); the outlet B2 of the two-stage piston compressor (4) is connected to the inlet of the evaporator (2) via the low-temperature throttle valve (12); The outlet B4 of the heat exchanger (7) is also connected to the inlet of the evaporator (2) through the high-temperature throttle valve (14).

2. The energy-saving high and low temperature environment test chamber refrigeration system according to claim 1 is characterized in that: The system further comprises a four-way valve (3), wherein the four-way valve (3) comprises an inlet A5 and an outlet B5 which are interconnected, and an inlet A6 and an outlet B6 which are interconnected; the outlet of the evaporator (2) is connected to the inlet A1 of the two-stage piston compressor (4) and the inlet of the scroll compressor (5) through the inlet A5 and the outlet B5; The system further comprises a gas-liquid separator (6), wherein the outlet B1 of the two-stage piston compressor (4) and the outlet of the scroll compressor (5) are both connected to the inlet A4 of the heat exchanger (7) through the gas-liquid separator (6); The system further comprises a return air low temperature protection branch, on which a return air low temperature solenoid valve (15) is provided, one end of the return air low temperature protection branch is connected to the outlet of the gas-liquid separator (6), and the other end of the return air low temperature protection branch is connected to the inlet A4 of the heat exchanger (7) via the inlet A6 and the outlet B6 of the four-way valve (3).

3. The energy-saving high and low temperature environment test chamber refrigeration system according to claim 2 is characterized in that: The system also includes a low-temperature energy regulating branch, on which a low-temperature energy solenoid valve (16) and a low-temperature energy regulating valve (17) are provided, one end of the low-temperature energy regulating branch is connected to the outlet of the gas-liquid separator (6), and the other end of the low-temperature energy regulating branch is connected to the outlet of the low-temperature throttling valve (12).

4. The energy-saving high and low temperature environment test chamber refrigeration system according to claim 2 is characterized in that: The system also includes a high-temperature energy regulating branch, on which a high-temperature energy solenoid valve (18) and a high-temperature energy regulating valve (19) are provided, one end of the high-temperature energy regulating branch is connected to the outlet of the gas-liquid separator (6), and the other end of the high-temperature energy regulating branch is connected to the outlet of the high-temperature throttle valve (14).

5. A control method for an energy-saving high and low temperature environment test chamber refrigeration system, characterized in that: The control method is used to control the system according to claim 1, and the control method comprises the following steps: S1: When the required temperature of the test load (22) is within a preset low temperature range, a two-stage piston compressor (4) is used for refrigeration, and a frequency converter is provided to achieve a cooling capacity output of the two-stage piston compressor (4) of 45%-100%; S2: When the required temperature of the test load (22) is within a preset high temperature range, the scroll compressor (5) is used for refrigeration, so that the scroll compressor (5) achieves a cooling capacity output of 20%-100%; S3: The heater (1) is used for heating operation, and a controller is used to adjust the energy from 0 to 100%.

6. The control method of the energy-saving high and low temperature environment test chamber refrigeration system according to claim 5, characterized in that: The control method further comprises the following steps: S4: When the two-stage piston compressor (4) or the scroll compressor (5) is at the lowest output condition, an energy regulating valve is used to control the output of the two-stage piston compressor (4) or the scroll compressor (5) to achieve energy regulation of 10%-100%.

7. The control method of the energy-saving high and low temperature environment test chamber refrigeration system according to claim 6, characterized in that: In the case where system refrigeration is required, the control method further comprises the following steps: Execute S1 or S2 to meet different required temperatures of the test load (22); Executing S4, continuing to reduce the output of the two-stage piston compressor (4) or the scroll compressor (5) to maintain the required temperature; After the test load (22) is turned on, the output of the two-stage piston compressor (4) or the scroll compressor (5) is gradually increased to maintain the required temperature.

8. The control method of the energy-saving high and low temperature environment test chamber refrigeration system according to claim 6, characterized in that: When the system needs to heat, the control method further includes the following steps: According to the required temperature, the power of the heater (1) is controlled to increase the temperature of the test load (22); When the difference between the required temperature and the temperature of the test load (22) is less than a threshold value, the power of the heater (1) begins to be reduced to maintain the temperature of the test load (22) at the required temperature; After the test load (22) is turned on, S2 is executed to perform heat balance to maintain the required temperature.

9. The control method of the energy-saving high and low temperature environment test chamber refrigeration system according to claim 8, characterized in that: After the test load (22) is turned on, S2 is executed to perform heat balance to maintain the required temperature, including: The scroll compressor (5) is controlled to output 20%-40% of the cooling capacity.

10. The control method of the energy-saving high and low temperature environment test chamber refrigeration system according to claim 5, characterized in that: The preset low temperature range is -40°C to -15°C, and the preset high temperature range is -15°C to 150°C.

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