Low-carbon large-temperature-span refrigerating system

Abstract

The utility model discloses a low-carbon large-temperature-span refrigerating system, which relates to the field of refrigeration and cold carrying, and comprises a compressor, a condenser, a first working medium pump, a first connecting mechanism, a second connecting mechanism and a control mechanism, the condenser and the first working medium pump are sequentially connected with the output end of the compressor, the first connecting mechanism is connected with one outlet of the first working medium pump, and the second connecting mechanism is connected with the other outlet of the second working medium pump. And the second connecting mechanism is connected with the other outlet of the first working medium pump. The single-stage vapor compression ultralow-temperature refrigeration effect is achieved by optimizing the system process and configuring the low-GWP mixed working medium, on one hand, expansion work generated in the throttling process is recycled through the pressure adjusting attribute of the ejector, on the other hand, the system performance is improved through the flow adjusting attribute of the ejector, and the system performance is improved. Working media of a cold carrying system and a refrigerating system are reasonably and effectively regulated and controlled, so that the concentration of working medium components participating in circulation is precisely regulated and controlled under the aim of refrigerating in different temperature zones.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration cooling, and in particular to a low-carbon, high-temperature refrigeration system. Background Technology

[0002] With global warming and rising temperatures, new refrigeration technologies using low-GWP environmentally friendly refrigerants are one of the important development directions for the future of the refrigeration and freezing industry.

[0003] However, due to limitations in refrigerant properties and compressor operating pressure ratio, current single-stage vapor compression refrigeration systems cannot achieve refrigeration below -40°C. Possible solutions include replacing the system flow with a cascade cycle system or a multi-stage compression system, but this would lead to increased system complexity and cost, which is inconvenient. Utility Model Content

[0004] The purpose of this invention is to provide a low-carbon, high-temperature-span refrigeration system to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a low-carbon, high-temperature refrigeration system, comprising:

[0006] compressor;

[0007] A condenser and a first working fluid pump, wherein the condenser and the first working fluid pump are sequentially connected to the output end of the compressor;

[0008] A first connecting mechanism is connected to one of the outlets of a first working fluid pump. The first connecting mechanism includes:

[0009] A first expansion valve is connected to one of the outlets of a first working fluid pump;

[0010] The first injector, the outlet of the first expansion valve is connected to the high-pressure inlet of the first injector;

[0011] A second connecting mechanism is connected to another outlet of the first working fluid pump, and the second connecting mechanism includes:

[0012] A regenerator, wherein the high-temperature side inlet of the regenerator is connected to the other outlet of the first working fluid pump;

[0013] The second expansion valve and the first gas-liquid separator are connected in sequence. The high-temperature outlet of the regenerator is connected to the second expansion valve and the inlet of the first gas-liquid separator in sequence. The gas phase outlet of the first gas-liquid separator is connected to the outlet of the first ejector, and is connected in sequence to the low-temperature side inlet and outlet of the regenerator and the inlet of the compressor.

[0014] The third expansion valve and the second gas-liquid separator are connected in sequence to the third expansion valve and the second gas-liquid separator.

[0015] The evaporator, the liquid phase outlet of the second gas-liquid separator is connected in sequence to the evaporator refrigeration side inlet and outlet, and the low-pressure inlet of the first ejector;

[0016] The first shut-off valve and the gas phase outlet of the second gas-liquid separator are sequentially connected to the first shut-off valve and the low-pressure inlet of the second injector.

[0017] The second ejector, the gas phase outlet of the second gas-liquid separator is connected in sequence to the first shut-off valve and the low-pressure inlet of the second ejector, and the outlet of the second ejector is connected to the inlet of the evaporator on the cooling side.

[0018] The second working fluid pump and the heat exchanger are connected in sequence to the second working fluid pump, the heat exchanger, and the high-pressure inlet of the second ejector.

[0019] The second shut-off valve is connected in sequence to the first outlet of the evaporator on the cooling side and the low-pressure inlet of the first ejector.

[0020] A control mechanism is connected to the compressor, the first connecting mechanism, and the second connecting mechanism.

[0021] Preferably, the control mechanism includes:

[0022] The control module has its output terminals connected to the compressor, the first expansion valve, the first injector, the second expansion valve, the expansion valve, the first shut-off valve, and the second shut-off valve, respectively.

[0023] A first temperature sensor is mounted on the evaporator, and the input terminal of the control module is connected to the first temperature sensor.

[0024] A component concentration sensor is provided, which is disposed between the third expansion valve and the second gas-liquid separator, and the input terminal of the control module is connected to the component concentration sensor.

[0025] The second temperature sensor is installed on the cooling heat exchanger, and the input terminal of the control module is connected to the second temperature sensor.

[0026] Preferably, the regenerator is provided with a high-temperature side fluid channel and an inlet and an outlet, and a low-temperature side fluid channel and an inlet and an outlet. The high-temperature side fluid channel and the low-temperature side fluid channel exchange heat through conduction, convection and radiation, without mass exchange. The refrigerant component concentrations corresponding to the two fluid channels inside the regenerator are the same.

[0027] Preferably, the evaporator is provided with a refrigeration-side fluid channel and an inlet and an outlet, and a cooling-side fluid channel and an inlet and an outlet. The refrigeration-side fluid channel and the cooling-side fluid channel exchange heat through conduction, convection, and radiation, without mass exchange. The refrigerant component flows in the refrigeration-side fluid channel and the inlet and outlet of the evaporator, and the cooling-side fluid channel and the inlet and outlet of the evaporator contain a cooling-side refrigerant component.

[0028] The technical effects and advantages of this utility model are as follows:

[0029] This invention utilizes an optimized system process and a low-GWP mixed working fluid to achieve single-stage vapor compression cryogenic refrigeration. By adjusting the pressure of the ejector, the expansion work generated during the throttling process is recovered to improve system performance. On the other hand, the flow rate adjustment of the ejector allows for reasonable and effective control of the working fluid in the cooling system and the refrigeration system. This enables precise control of the concentration of working fluid components participating in the cycle under different temperature zones, making it easy to use. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a low-carbon, high-temperature refrigeration system according to the present invention.

[0031] In the diagram: 101, compressor; 102, condenser; 103, first working fluid pump; 104, first expansion valve; 105, first ejector; 106, regenerator; 107, second expansion valve; 108, first gas-liquid separator; 109, third expansion valve; 110, second gas-liquid separator; 111, evaporator; 112, first shut-off valve; 113, second ejector; 114, second working fluid pump; 115, refrigeration heat exchanger; 116, second shut-off valve; 201, control module; 202, first temperature sensor; 203, component concentration sensor; 204, second temperature sensor. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] This utility model provides, for example Figure 1The low-carbon, high-temperature refrigeration system shown includes a compressor 101, a condenser 102, a first working fluid pump 103, a first connecting mechanism, a second connecting mechanism, and a control mechanism. The condenser 102 and the first working fluid pump 103 are sequentially connected to the output end of the compressor 101. The first connecting mechanism is connected to one outlet of the first working fluid pump 103. The second connecting mechanism is connected to the other outlet of the first working fluid pump 103. The control mechanism is connected to the compressor 101, the first connecting mechanism, and the second connecting mechanism.

[0034] The first connecting mechanism includes a first expansion valve 104 and a first ejector 105. The first expansion valve 104 is connected to one of the outlets of the first working fluid pump 103. The outlet of the first expansion valve 104 is connected to the high-pressure inlet of the first ejector 105. The first expansion valve 104 can throttle and reduce the pressure of the working fluid flowing out of the outlet of the first working fluid pump 103, providing suitable pressure conditions for the first ejector 105, which helps to improve the energy utilization efficiency of the system. The first ejector 105 can use the pressure difference of the working fluid to achieve an ejection effect, mixing the low-temperature and low-pressure working fluid with the high-pressure working fluid, increasing the pressure and energy of the working fluid, and promoting the circulation of the entire refrigeration system.

[0035] The second connection mechanism includes a regenerator 106, a second expansion valve 107, a first gas-liquid separator 108, a third expansion valve 109, a second gas-liquid separator 110, an evaporator 111, a first shut-off valve 112, a second ejector 113, a second working fluid pump 114, a cooling heat exchanger 115, and a second shut-off valve 116. The high-temperature inlet of the regenerator 106 is connected to the other outlet of the first working fluid pump 103. The high-temperature outlet of the regenerator 106 is sequentially connected to the second expansion valve 107 and the inlet of the first gas-liquid separator 108. The gas phase outlet of the first gas-liquid separator 108 is connected to the outlet of the first ejector 105, and sequentially connected to the low-temperature inlet and outlet of the regenerator 106. The first gas-liquid separator 108 is connected to the inlet of the compressor 101; the liquid phase outlet of the first gas-liquid separator 108 is connected in sequence to the third expansion valve 109 and the second gas-liquid separator 110; the liquid phase outlet of the second gas-liquid separator 110 is connected in sequence to the refrigeration side inlet and outlet of the evaporator 111 and the low-pressure inlet of the first ejector 105; the gas phase outlet of the second gas-liquid separator 110 is connected in sequence to the low-pressure inlet of the first shut-off valve 112 and the second ejector 113; the gas phase outlet of the second gas-liquid separator 110 is connected in sequence to the low-pressure inlet of the first shut-off valve 112 and the second ejector 113, and the outlet of the second ejector 113 is connected to the cooling side inlet of the evaporator 111; the second outlet of the cooling side of the evaporator 111... The evaporator 111 is connected in sequence to the second working fluid pump 114, the cooling heat exchanger 115, and the high-pressure inlet of the second ejector 113. The first outlet on the cooling side of the evaporator 111 is connected in sequence to the second shut-off valve 116 and the low-pressure inlet of the first ejector 105. The regenerator 106 can realize heat recovery and transfer, transferring the heat of the working fluid flowing out from the high-temperature side to the working fluid on the low-temperature side, improving energy utilization efficiency and reducing energy loss. The second expansion valve 107 can further throttle and reduce the pressure of the working fluid flowing out from the high-temperature outlet of the regenerator 106, preparing for subsequent gas-liquid separation processes. The first gas-liquid separator 108 can separate the gas-liquid mixed working fluid, and the gas phase can be mixed with the working fluid at the outlet of the first ejector 105. The liquid phase can enter the second gas-liquid separator 110 after passing through the third expansion valve 109, achieving preliminary separation and graded utilization of the working fluid. The second gas-liquid separator 110 also plays the role of gas-liquid separation. The liquid phase enters the evaporator 111 for refrigeration, while the gas phase participates in subsequent processes such as injection, ensuring the purity and rational utilization of the working fluid in the system. The evaporator 111 achieves refrigeration through circulation on the cooling side. The first shut-off valve 112 and the second shut-off valve 116 can control the on / off of the working fluid, facilitating system adjustment and maintenance. The second ejector 113 uses working fluids at different pressures for injection, and works in conjunction with the cooling heat exchanger 115, etc., to further improve the system's refrigeration effect and energy utilization efficiency.

[0036] The control mechanism includes a control module 201, a first temperature sensor 202, a component concentration sensor 203, and a second temperature sensor 204. The output of the control module 201 is connected to the compressor 101, the first expansion valve 104, the first injector 105, the second expansion valve 107, the first gas-liquid separator 108, the first shut-off valve 112, and the second shut-off valve 116, respectively. The temperature sensor is mounted on the evaporator 111, and the input of the control module 201 is connected to the first temperature sensor 202. The component concentration sensor 203 is mounted on the third expansion valve 109. Between the second gas-liquid separator 110 and the second gas-liquid separator 110, the input terminal of the control module 201 is connected to the component concentration sensor 203; the second temperature sensor 204 is installed on the cooling heat exchanger 115, and the input terminal of the control module 201 is connected to the second temperature sensor 204. The configuration of the control mechanism enables the system to be precisely controlled according to different working conditions and requirements. Through the connection between the control module 201 and various components, the operating parameters of the system, such as temperature and component concentration, can be monitored and adjusted in real time to ensure that the system operates in the best condition and improve the stability and reliability of the system.

[0037] The regenerator 106 is provided with a high-temperature side fluid channel and an inlet and an outlet, and a low-temperature side fluid channel and an inlet and an outlet. The high-temperature side fluid channel and the low-temperature side fluid channel exchange heat through conduction, convection and radiation, without mass exchange. The refrigerant component concentrations corresponding to the two fluid channels inside the regenerator 106 are the same.

[0038] The evaporator 111 is provided with a refrigeration-side fluid channel and inlet and outlet, and a cooling-side fluid channel and inlet and outlet. Heat exchange occurs between the refrigeration-side fluid channel and the cooling-side fluid channel through conduction, convection, and radiation, without mass exchange. The refrigerant component flows in the refrigeration-side fluid channel and inlet and outlet of the evaporator 111, and the cooling-side fluid channel and inlet and outlet of the evaporator 111 contains a cooling-side refrigerant component. The cooling-side refrigerant component is a single component carbon dioxide, and the refrigerant component is any combination of methane, ethane, propane, and isobutane. The combination of methane, ethane, propane, and isobutane is selected according to the target refrigeration temperature.

[0039] The control method of this utility model:

[0040] S1: When the cooling temperature is between -20℃ and -40℃, the rated cooling temperature mode is used, and the target rated cooling temperature is determined according to the pre-designed refrigerant composition;

[0041] S2: When the cooling temperature is between -80℃ and -40℃, a low-temperature cooling mode is adopted. Carbon dioxide, the refrigerant in the cooling process, is introduced into the cooling process. By increasing the low-temperature refrigerant components that participate in the circulation of the cooling process, a low-temperature cooling effect lower than the rated cooling temperature is achieved.

[0042] S3: When the cooling temperature is between -20℃ and 0℃, a high-temperature cooling mode is adopted. Through the second ejector 113, the gaseous low-temperature refrigerant rich in carbon dioxide in the cooling process is extracted to the cooling process. By reducing the low-temperature refrigerant components that participate in the circulation of the cooling process, a higher cooling effect than the rated cooling temperature is achieved.

[0043] The rated cooling temperature modes in S1 include:

[0044] S11: The first expansion valve 104 is opened to 50%, and the control module 201 is connected to the first temperature sensor 202 to collect the refrigeration side outlet temperature of the evaporator 111.

[0045] S12: If the refrigeration side outlet temperature of the evaporator 111 is higher than the set rated refrigeration temperature, gradually reduce the opening of the second expansion valve 107 and the third expansion valve 109, and increase the speed of the compressor 101 until the rated refrigeration effect is achieved. Then, keep the speed of the compressor 101 unchanged and the opening of the second expansion valve 107 and the third expansion valve 109 unchanged.

[0046] The S2 low-temperature cooling mode includes the following steps:

[0047] S21: The first expansion valve 104 is 100% open, and the control module 201 is connected to the first temperature sensor 202 to collect the refrigeration side outlet temperature of the evaporator 111.

[0048] S22: Control module 201 is connected to component concentration sensor 203 to collect refrigerant composition after third expansion valve 109, and control module 201 is connected to second temperature sensor 204 to collect refrigerant temperature at outlet of refrigerant heat exchanger 115.

[0049] S23: If the refrigerant temperature at the outlet of the heat exchanger 115 is higher than or equal to the rated refrigeration temperature, close the first shut-off valve 112, open the second shut-off valve 116, gradually reduce the opening of the second expansion valve 107 and the third expansion valve 109, and increase the speed of the compressor 101.

[0050] S24: If the component concentration sensor 203 detects that the carbon dioxide in the refrigerant component after the third expansion valve 109 exceeds 15%, and the refrigerant temperature at the outlet of the heat exchanger 115 reaches the set low-temperature refrigeration temperature, the second shut-off valve 116 is closed, the compressor 101 speed is kept constant, and the opening of the second expansion valve 107 and the third expansion valve 109 remains unchanged.

[0051] The S3 high-temperature cooling mode includes the following steps:

[0052] S31: The first expansion valve 104 is opened to 50%, and the control module 201 is connected to the first temperature sensor 202 to collect the refrigeration side outlet temperature of the evaporator 111.

[0053] S32: Control module 201 is connected to component concentration sensor 203 to collect refrigerant composition after third expansion valve 109, and control module 201 is connected to second temperature sensor 204 to collect refrigerant temperature at outlet of refrigerant heat exchanger 115.

[0054] S33: If the refrigerant temperature at the outlet of the heat exchanger 115 is lower than or equal to the rated refrigeration temperature, open the first shut-off valve 112, close the second shut-off valve 116, gradually increase the opening of the second expansion valve 107 and the third expansion valve 109, and reduce the speed of the compressor 101.

[0055] S34: If the component concentration sensor 203 detects that the carbon dioxide concentration in the refrigerant component after the third expansion valve 109 is less than 1%, and the refrigerant temperature at the outlet of the heat exchanger 115 reaches the set high-temperature refrigeration temperature, the first shut-off valve 112 is closed, the compressor 101 speed is kept constant, and the opening of the second expansion valve 107 and the third expansion valve 109 remains unchanged.

[0056] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low carbon large temperature span refrigeration system, characterized in that, Compressor (101); Condenser (102) and first working medium pump (103), the condenser (102), first working medium pump (103) are connected with the output end of compressor (101) in turn; First connecting mechanism, one of the outlets of first working medium pump (103) is connected with the first connecting mechanism, and the first connecting mechanism comprises: First expansion valve (104), one of the outlets of first working medium pump (103) is connected with the first expansion valve (104); First ejector (105), the outlet of first expansion valve (104) is connected with the high pressure inlet of first ejector (105); Second connecting mechanism, the other outlet of first working medium pump (103) is connected with the second connecting mechanism, and the second connecting mechanism comprises: Heat regenerator (106), the high temperature side inlet of heat regenerator (106) is connected with the other outlet of first working medium pump (103); Second expansion valve (107) and first gas-liquid separator (108), the high temperature outlet of heat regenerator (106) is connected with second expansion valve (107) and first gas-liquid separator (108) inlet in turn, the gas phase outlet of first gas-liquid separator (108) is connected with the outlet of first ejector (105), and is connected with the low temperature side inlet and outlet of heat regenerator (106) and the inlet of compressor (101) in turn; Third expansion valve (109) and second gas-liquid separator (110), the liquid phase outlet of first gas-liquid separator (108) is connected with third expansion valve (109) and second gas-liquid separator (110) in turn; Evaporator (111), the liquid phase outlet of second gas-liquid separator (110) is connected with evaporator (111) refrigeration side inlet and outlet and first ejector (105) low pressure inlet in turn; First stop valve (112), the gas phase outlet of second gas-liquid separator (110) is connected with first stop valve (112) and second ejector (113) low pressure inlet in turn; Second ejector (113), the gas phase outlet of second gas-liquid separator (110) is connected with first stop valve (112) and second ejector (113) low pressure inlet in turn, and the outlet of second ejector (113) is connected with evaporator (111) cooling side inlet; Second working medium pump (114) and cooling heat exchanger (115), the cooling side second outlet of evaporator (111) is connected with second working medium pump (114), cooling heat exchanger (115) and second ejector (113) high pressure inlet in turn; Second stop valve (116), the cooling side first outlet of evaporator (111) is connected with second stop valve (116) and first ejector (105) low pressure inlet in turn; Control mechanism, the control mechanism is connected with compressor (101), first connecting mechanism and second connecting mechanism. The control mechanism comprises:

2. The low-carbon large temperature glide refrigeration system of claim 1, wherein, ​ A control module (201) is connected to the compressor (101), the first expansion valve (104), the first ejector (105), the second expansion valve (107), the first gas-liquid separator (108), the first stop valve (112) and the second stop valve (116) respectively; A first temperature sensor (202) is arranged on the evaporator (111), and the control module (201) is connected to the first temperature sensor (202); A component concentration sensor (203) is arranged between the third expansion valve (109) and the second gas-liquid separator (110), and the control module (201) is connected to the component concentration sensor (203); A second temperature sensor (204) is arranged on the cold storage heat exchanger (115), and the control module (201) is connected to the second temperature sensor (204).

3. The low-carbon large temperature glide refrigeration system of claim 1, wherein, The regenerator (106) is provided with a high-temperature side fluid passage and an inlet and an outlet, and a low-temperature side fluid passage and an inlet and an outlet, the high-temperature side fluid passage and the low-temperature side fluid passage exchange heat through conduction, convection and radiation, and do not exchange mass, and the component concentration of the refrigerant corresponding to the two fluid passages inside the regenerator (106) is consistent.

4. The low-carbon large temperature glide refrigeration system of claim 1, wherein, The evaporator (111) is provided with a refrigeration side fluid passage and an inlet and an outlet, and a cold storage side fluid passage and an inlet and an outlet, the refrigeration side fluid passage and the cold storage side fluid passage exchange heat through conduction, convection and radiation, and do not exchange mass, the refrigeration side fluid passage and the inlet and the outlet inside the evaporator (111) flow with a refrigerant component, and the cold storage side fluid passage and the inlet and the outlet inside the evaporator (111) flow with a cold storage agent component.

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