Solar-driven mixed working medium two-stage separation low-temperature refrigeration method and refrigeration system

Abstract

The present invention discloses a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration method and refrigeration system, wherein the superheated mixed refrigerant vapor discharged from the generator enters the ejector assembly as the working fluid, and the high-pressure superheated refrigerant vapor discharged from the ejector assembly is cooled and lowered in the first regenerator and then enters the condenser to realize partial condensation of the mixed refrigerant to form a gas-liquid two-phase mixture, and the gas-liquid two-phase mixture flows into the second regenerator and is further cooled so that the low-boiling-point component in the gas phase is partially condensed into liquid, and enters the two-stage gas-liquid separator unit for a flash separation step; this solution improves the purity of the low-boiling-point component through multi-stage condensation and graded condensation technology, thereby obtaining a lower refrigeration temperature, and improves the system energy efficiency ratio through the cascade utilization of cooling capacity.

Description

Technical Field

[0001] The present invention belongs to mixed working fluid throttling refrigeration technology, and in particular relates to a solar-driven mixed working fluid two-stage separation low-temperature refrigeration method and a refrigeration system. Background Art

[0002] As is well known, the first world-recognized ejector was invented in the early 20th century, but it did not gain significant attention until the mid-20th century. Numerous new energy-saving technologies were developed as compressor replacements or for cycle optimization. An ejector is a device powered by thermal energy, utilizing the heat absorption of a working fluid during evaporation at low pressure and employing a Laval nozzle to achieve thermal compression of the working fluid vapor. Compared to traditional compressors, ejectors offer advantages such as simple structure, low cost, and high reliability. Although ejector refrigeration offers the advantage of utilizing renewable energy sources such as solar energy, geothermal energy, and industrial waste heat, it utilizes a single-component refrigerant and the ejector's low compression ratio, making it difficult to achieve the required condensing pressure for the condenser's cooling medium at higher temperatures. Consequently, the refrigeration temperature is high and the system is inefficient. One existing technology utilizes a compressor-driven refrigeration cycle to achieve lower refrigeration temperatures. However, due to the high-quality electrical energy consumption, electrically driven compression refrigeration cycles are increasingly facing challenges in the current environment. Low-quality energy-driven ejector refrigeration cycles offer broader application prospects. Furthermore, single-stage systems, limited by their low boiling point purity, struggle to achieve lower refrigeration temperatures. Summary of the Invention

[0003] The purpose of the present invention is to provide a solar-driven mixed-refrigerant low-temperature refrigeration method and refrigeration system, which improves the purity of low-boiling-point components through multi-stage condensation and graded condensation technology, thereby obtaining a lower refrigeration temperature and improving the system energy efficiency ratio through the cascade utilization of cooling capacity.

[0004] One of the purposes of the present invention is to provide a solar-driven two-stage separation low-temperature refrigeration method for mixed refrigerants, the specific steps of which are as follows: the superheated mixed refrigerant vapor discharged from the generator enters the ejector assembly as a working fluid, the high-pressure superheated refrigerant vapor discharged from the ejector assembly is cooled and lowered in the first regenerator, and then enters the condenser to realize partial condensation of the mixed refrigerant to form a gas-liquid two-phase mixture, the gas-liquid two-phase mixture flows into the second regenerator and is further cooled so that the low-boiling point component in the gas phase is partially condensed into liquid, and enters the two-stage gas-liquid separator unit for a flash separation step.

[0005] As a preferred embodiment, the flash separation step is specifically as follows:

[0006] Pre-separation steps:

[0007] The liquid refrigerant obtained by condensing the refrigerant vapor discharged from the working medium outlet of the ejector assembly enters the front-stage gas-liquid separator for a first-stage flash separation and is separated into a gas phase mixed working medium rich in low-boiling point components and a liquid phase mixed working medium rich in high-boiling point components;

[0008] The first part of the liquid phase mixed working fluid flowing out of the bottom of the front-stage gas-liquid separator is sent to the first regenerator to recover the heat of the refrigerant vapor at the outlet of the ejector assembly, and then sent to the generator through the working fluid pump to be heated into refrigerant vapor and serve as the working fluid of the ejector assembly;

[0009] The second part of the liquid phase mixed working medium flowing out of the bottom of the front-stage gas-liquid separator is throttled and depressurized by the throttling component to become a refrigerant working medium with a lower temperature and intermediate pressure, and flows into the front-stage evaporative condenser and the front-stage partial condenser in turn to be utilized in cascade;

[0010] Post-separation steps:

[0011] The refrigerant at the gas outlet of the front-stage gas-liquid separator is condensed into a gas-liquid two-phase mixture after heat exchange in the front-stage evaporative condenser;

[0012] Entering the back-stage gas-liquid separator for flash separation and separation into a gas phase mixed working fluid rich in low boiling point components and a liquid phase mixed working fluid rich in high boiling point components;

[0013] The liquid mixed working medium flowing out from the bottom of the rear-stage gas-liquid separator is throttled and reduced in pressure by the throttling component to become a refrigerant working medium with a lower temperature and intermediate pressure, and flows into the rear-stage evaporative condenser, the front-stage evaporative condenser and the front-stage partial condenser in turn for cascade utilization.

[0014] As a preferred embodiment, it also includes a step distillation step:

[0015] The first part of the liquid-phase mixed working medium flowing out of the bottom of the front-stage gas-liquid separator is mixed with the liquid-phase mixed working medium flowing out of the bottom of the rear-stage gas-liquid separator, and the gas-phase mixed working medium flashed and separated in the front-stage gas-liquid separator is subjected to a stepwise distillation and stepwise condensation process at an intermediate evaporation pressure, and then is sucked into the ejector assembly as an ejector fluid for a single-stage pressure boosting process;

[0016] The gaseous mixed working fluid with low boiling point components flowing out from the top of the rear-stage gas-liquid separator is condensed into liquid, which realizes the cascade utilization and cascade distillation of cooling capacity at low evaporation pressure. The formed gaseous working fluid is sucked into the ejector assembly as the ejector fluid to complete the two-stage pressurization process.

[0017] As a preferred solution, the gaseous mixed working fluid of the low-boiling-point component flowing out from the top of the rear-stage gas-liquid separator is first condensed into liquid by the rear-stage evaporative condenser, and the first-stage low-temperature cold utilization is completed; then it enters the third regenerator, the rear-stage partial condenser and the second regenerator in sequence to realize the second-stage, third-stage and fourth-stage cascade utilization of cold.

[0018] The second object of the present invention is to provide a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration system, comprising an ejector assembly and a two-stage gas-liquid separation unit, the outlet end of the ejector assembly being connected to the refrigerant inlet of the two-stage gas-liquid separation unit, the high-pressure superheated refrigerant vapor discharged by the ejector assembly passing through the two-stage gas-liquid separation unit to achieve two-stage separation, the two-stage gas-liquid separation unit comprising a front-stage gas-liquid separator and a rear-stage gas-liquid separator; the top gas outlet of the front-stage gas-liquid separator is connected to the refrigerant inlet of the rear-stage gas-liquid separator, one of the branches of the bottom liquid outlet of the front-stage gas-liquid separator merges with the refrigerant refrigerant at the bottom liquid outlet of the rear-stage gas-liquid separator, and after heat exchange with the refrigerant refrigerant discharged from the top gas outlet of the front-stage gas-liquid separator, enters the front-stage condenser above the liquid level in the front-stage gas-liquid separator, for distilling and purifying the mixed refrigerant vapor flash-evaporated by the front-stage gas-liquid separator.

[0019] As a preferred embodiment, the refrigerant discharged from the top gas outlet of the rear-stage gas-liquid separator and the refrigerant discharged from the bottom liquid outlet thereof, after being evaporated and absorbing heat through the evaporator assembly, enter the rear-stage condenser above the liquid level in the rear-stage gas-liquid separator, for performing a distillation and purification process on the mixed working fluid vapor flash-separated by the rear-stage gas-liquid separator.

[0020] As a preferred solution, the bottom liquid outlet of the front-stage gas-liquid separator is divided into two branches, wherein the refrigerant in the first branch finally enters the generator after being throttled by the throttling component, and the refrigerant in the second branch is throttled by the throttling component and connected to the first channel outlet of the rear-stage evaporative condenser and the inlet of the first channel of the front-stage evaporative condenser, thereby realizing heat exchange with the refrigerant in the second channel of the front-stage evaporative condenser.

[0021] As a preferred embodiment, it also includes a heat recovery condensing unit arranged on the pipeline between the ejector assembly and the front-stage gas-liquid separator, and the heat recovery condensing unit includes a first heat exchanger, a condenser and a second heat exchanger. The first heat exchanger is used for heat exchange between the refrigerant working fluid of the first branch of the bottom liquid outlet of the front-stage gas-liquid separator and the working fluid at the outlet of the ejector assembly. The condenser is arranged on the high-pressure side channel outlet pipeline of the first heat exchanger, and is used to pass the refrigerant working fluid after the ejector assembly releases heat through the high-pressure side channel of the first heat exchanger into the condenser, so as to realize partial condensation of the mixed working fluid and form a gas-liquid two-phase mixture; the second heat exchanger is used for heat exchange between the gas-liquid two-phase mixture discharged from the condenser and the refrigerant working fluid discharged from the rear-stage condenser.

[0022] As a preferred embodiment, it also includes a solar thermal collection unit, which includes a solar thermal collector, a heat storage tank and a hot water pump. The solar thermal collector, heat storage tank and hot water pump are connected in sequence to form a circulation loop. The circulation loop is connected to the inlet and outlet of the heating channel of the generator, and is used to use the heat energy converted from solar energy to heat the refrigerant working fluid of the generator into refrigerant vapor for discharge. The working fluid outlet of the generator is connected to the working fluid inlet of the ejector assembly.

[0023] The beneficial effects of the present invention include at least:

[0024] First, the present invention optimizes the refrigeration process and organically combines two-stage separation technology, graded condensation and graded fractional condensation technology to effectively achieve the step-by-step separation, step-by-step distillation purification and step-by-step utilization of low-temperature cooling capacity of the mixed working fluid. By improving the purity of low-boiling-point components, a lower refrigeration temperature is obtained, and the system energy efficiency ratio is effectively improved through the step-by-step pressure increase and step-by-step utilization of cooling capacity of high and low boiling-point components.

[0025] Secondly, in this scheme, the working fluid with low boiling point components flowing out from the top of the rear-stage gas-liquid separator needs to undergo a two-stage ejector pressure boosting process after the low-pressure and low-temperature refrigeration effect, while the liquid rich in high boiling point components separated from the bottom of the front-stage gas-liquid separator and the rear-stage gas-liquid separator only needs to enter the second-stage ejector for a single-stage pressure boosting process after the medium-pressure and lower-temperature refrigeration effect, thereby realizing a graded compression process of high-boiling point components and low-boiling point components. Compared with the single-stage ejector refrigeration cycle, this can significantly improve the system refrigeration efficiency or obtain a lower refrigeration temperature.

[0026] Third, in order to achieve a lower refrigeration temperature, this solution must adopt a two-stage separation system. Otherwise, the purity of the low-boiling-point components is not high, making it difficult to achieve a relatively low-temperature refrigeration temperature. According to the needs of the two-stage refrigeration process, the two-stage graded condensation system has been rationally optimized. The bottom outlet of the front-stage gas-liquid separator is divided into two branches. One branch enters the generator and becomes high-temperature and high-pressure refrigerant vapor as the working fluid to enter the ejector to eject the refrigerant vapor on the evaporator side, thus serving as the basic power for the operation of the jet refrigeration cycle; the other branch will be combined with the working fluid at the bottom outlet of the rear-stage gas-liquid separator to partially condense the rich and low-boiling-point mixed working fluid separated at the top outlet of the front-stage gas-liquid separator, so as to achieve the purpose of two-stage separation of the mixed working fluid and improve the purity of the low-boiling-point components flowing out of the top of the rear-stage gas-liquid separator. This system uses the jet refrigeration cycle and the flash evaporation separation system for a rational combination design, which can achieve a refrigeration temperature below -30℃ or even lower. After the improvement, this system has significant energy-saving effects, reliable and stable operation, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a solar-driven mixed-refrigerant low-temperature refrigeration system and method according to embodiments 1 and 2 of the present invention;

[0028] Figure 2 This is a schematic diagram of a solar-driven mixed-refrigerant low-temperature refrigeration system according to Example 3 of the present invention;

[0029] Figure 3 This is a schematic diagram of a solar-driven mixed-refrigerant low-temperature refrigeration system according to Example 4 of the present invention;

[0030] Figure 4 This is a schematic diagram of a solar-driven mixed-refrigerant low-temperature refrigeration system according to Example 5 of the present invention;

[0031] Markings in the figure: 1. first generator, 2. second generator, 3. first ejector, 4. second ejector, 5. first regenerator, 6. condenser, 7. second regenerator, 8. front-stage gas-liquid separator, 9. first throttling component, 10. front-stage evaporative condenser, 11. front-stage partial condenser, 12. rear-stage gas-liquid separator, 13. second throttling component, 14. rear-stage evaporative condenser, 15. third regenerator, 16. third throttling component, 17. evaporator, 18. rear-stage partial condenser, 19. first working fluid pump, 20. first flow regulating valve, 21. second working fluid pump, 22. second flow regulating valve, 23. third flow regulating valve, 24. solar collector, 25. heat storage tank, 26. hot water pump, 27. fourth flow regulating valve. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, objectives and beneficial effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0033] Example 1

[0034] This embodiment uses Figure 1 Based on the structure of , a solar-driven mixed refrigerant low-temperature refrigeration method is provided, and the specific steps are as follows: the superheated mixed refrigerant vapor discharged from the first generator 1 enters the first ejector 3 as the working fluid to inject the mixed refrigerant with low boiling point components flowing out from the top of the rear-stage gas-liquid separator 12. The mixed refrigerant with low boiling point components serves as the injection fluid to complete the first-stage pressure boosting process in the first ejector 3 and become steam at intermediate pressure; the refrigerant discharged from the working fluid outlet of the first ejector 3 is used as the injection fluid of the second ejector 4, and becomes high-pressure superheated steam after the second-stage pressure boosting process of the second ejector 4.

[0035] The superheated mixed refrigerant vapor discharged from the second generator 2 serves as the working fluid of the second ejector 4 and ejects two parts of steam in addition to the intermediate pressure steam at the outlet of the first ejector 3. The first part of the steam is the intermediate pressure steam rich in high-boiling-point components that flows out from the bottom of the front-stage gas-liquid separator 8 and undergoes the throttling and pressure reduction process of the first throttling component 9 and the evaporation and heat absorption process of the front-stage evaporative condenser 10 and the front-stage partial condenser 11. The second part of the steam is the intermediate pressure steam rich in high-boiling-point components that flows out from the bottom of the rear-stage gas-liquid separator 12 and undergoes the throttling and pressure reduction process of the second throttling component 13 and the evaporation and heat absorption process of the rear-stage evaporative condenser 14, the front-stage evaporative condenser 10 and the front-stage partial condenser 11.

[0036] In this solution, the high-pressure superheated refrigerant vapor discharged by the second ejector 4 in the ejector assembly is cooled by the first regenerator 5 and then enters the condenser 6 to realize partial condensation of the mixed working fluid to form a gas-liquid two-phase mixture. The gas-liquid two-phase mixture flows into the second regenerator 7 to be further cooled so that the low-boiling-point component in the gas phase is partially condensed into liquid, and enters the front-stage gas-liquid separator 8 for a first-stage flash separation, thereby separating into a gas-phase mixed working fluid rich in low-boiling-point components and a liquid-phase mixed working fluid rich in high-boiling-point components.

[0037] A portion of the liquid-phase mixed working fluid flowing out of the bottom of the front-stage gas-liquid separator 8 recovers the steam heat at the outlet of the ejector assembly through the first regenerator 5, and is then sent into the generator through the working fluid pump for evaporation to serve as the working fluid of the ejector assembly; another portion of the liquid-phase mixed working fluid flowing out of the bottom of the front-stage gas-liquid separator 8 is throttled and reduced in pressure by the throttling component to become a refrigerant working fluid with a lower temperature and intermediate pressure; and flows into the front-stage evaporative condenser 10 and the front-stage partial condenser 11 successively to be utilized in a cascade manner.

[0038] In this solution, the gas-liquid two-phase mixture flowing out of the high-pressure side channel of the front-stage evaporative condenser 10 enters the rear-stage gas-liquid separator 12 for second-stage flash separation, and is separated into a gas-phase mixed working fluid rich in low-boiling-point components and a liquid-phase mixed working fluid rich in high-boiling-point components; the liquid-phase mixed working fluid flowing out of the bottom of the rear-stage gas-liquid separator 12 is throttled and reduced in pressure by a throttling component to become a refrigerant working fluid with a lower temperature and intermediate pressure, and flows into the rear-stage evaporative condenser 14, the front-stage evaporative condenser 10 and the front-stage partial condenser 11 in sequence to be utilized in a cascade manner.

[0039] After part of the liquid-phase mixed working fluid flowing out of the bottom of the front-stage gas-liquid separator 8 and the liquid-phase mixed working fluid flowing out of the rear-stage gas-liquid separator 12 are merged, the gas-phase mixed working fluid flashed and separated in the front-stage gas-liquid separator 8 will be subjected to a step-by-step distillation and step-by-step condensation process at the intermediate evaporation pressure, and then will be sucked into the ejector assembly as an ejector fluid for a single-stage pressurization process.

[0040] The gaseous mixed working fluid of the low-boiling-point components flowing out of the top of the rear-stage gas-liquid separator 12 is condensed into a liquid to realize the cascade utilization and cascade distillation of the cooling capacity at a low evaporation pressure. The formed gaseous working fluid is sucked into the ejector assembly as the ejector fluid to complete the two-stage pressurization process; the gaseous mixed working fluid of the low-boiling-point components flowing out of the top of the rear-stage gas-liquid separator 12 is first condensed into a liquid by the rear-stage evaporative condenser 14, and the first-stage low-temperature cooling capacity utilization is completed; then it enters the third regenerator 15, the rear-stage partial condenser 18 and the second regenerator 7 in sequence to realize the second-stage, third-stage and fourth-stage cascade utilization of cooling capacity.

[0041] This embodiment also includes a solar thermal collection unit, which includes a solar thermal collector 24, a heat storage tank 25 and a hot water pump 26. The solar thermal collector 24, the heat storage tank 25 and the hot water pump 26 are connected in sequence to form a circulation loop. The circulation loop is connected to the inlet and outlet of the heating channels of the first generator 1 and the second generator 2, and is used to use the heat energy converted from solar energy to heat the refrigerant working medium of the generator into refrigerant vapor for discharge.

[0042] In this scheme, the front and rear stage gas-liquid separators 8 and 12 both include a working fluid inlet, a top gas outlet and a bottom liquid outlet; the first and second evaporative condensers 10 and 14 both include two channels capable of heat exchange; the top gas phase outlet of the front stage gas-liquid separator 8 is connected to the working fluid inlet of the rear stage gas-liquid separator 12 through one side channel of the front stage evaporative condenser 10; the top gas outlet of the rear stage gas-liquid separator 12 is connected to one side channel of the rear stage evaporative condenser 14, and the bottom liquid outlet of the rear stage gas-liquid separator 12 is connected to the other side channel of the rear stage evaporative condenser 14; one of the branches of the bottom liquid outlet of the front stage gas-liquid separator 8 and the low-pressure side channel outlet of the rear stage evaporative condenser 14 are connected to the other side channel inlet of the front stage evaporative condenser 10.

[0043] In this solution, a pre-stage partial condenser 11 is provided above the internal liquid level of the pre-stage gas-liquid separator 8; the working fluid inlet of the pre-stage partial condenser 11 is connected to the low-pressure side channel outlet of the pre-stage evaporative condenser 10, and the pre-stage partial condenser 11 is used to perform a distillation and purification process on the mixed working fluid vapor separated by flash evaporation in the pre-stage gas-liquid separator 8. A post-stage partial condenser 18 is provided above the internal liquid level of the post-stage gas-liquid separator 12; the working fluid inlet of the post-stage partial condenser 18 is connected to the top gas outlet of the post-stage gas-liquid separator 12 through the evaporator assembly and one side channel of the second evaporative condenser 14, and the post-stage partial condenser 18 is used to perform a distillation and purification process on the mixed working fluid vapor rich in low-boiling-point components separated by the post-stage gas-liquid separator 12.

[0044] In this solution, a second throttling component 13 is provided on the pipeline between the bottom liquid phase outlet of the subsequent gas-liquid separator 12 and the low-pressure side channel inlet of the second evaporative condenser 14. The bottom liquid outlet of the preceding gas-liquid separator 8 is divided into two branches: the refrigerant in the first branch ultimately enters the first generator 1 and the second generator 2. The refrigerant in the second branch, after being throttled by the first throttling component 9, is connected to the high-pressure side channel outlet of the second evaporative condenser 14 and the inlet of one side channel of the preceding evaporative condenser 10, thereby exchanging heat with the refrigerant in the pipeline on the other side of the preceding evaporative condenser 10.

[0045] In this solution, because the evaporation pressure corresponding to low-temperature refrigeration is very low, the ratio of the ejector outlet pressure to the ejected fluid pressure (the ejector boost ratio) can exceed 2.0 or even reach 4.0. Since the ejector boost ratio is inherent to the ejector, it generally does not exceed 2.0. Therefore, to achieve lower refrigeration temperatures, a two-stage ejector boost is required. However, the liquid flowing out of the bottom of the gas-liquid separator may be at medium pressure after throttling, so a single-stage ejector can achieve the required boost ratio. As analyzed above, the liquid exiting the bottom of the gas-liquid separator does not require two stages of boosting after cooling to meet the required pressure. This is the fundamental reason why the gas-liquid separator in this solution uses staged boosting to separate the high-boiling-point and low-boiling-point components. This design is intended to be more energy-efficient than using a single ejector.

[0046] In this embodiment, the first reheater 5 includes a high-pressure side channel and a low-pressure side channel that can realize heat exchange. The inlet of the high-pressure side channel of the first reheater 5 is connected to the working fluid outlet of the second ejector 4 in the ejector assembly, and the outlet of the high-pressure side channel of the first reheater 5 is connected to the working fluid inlet of the front-stage gas-liquid separator 8; it is used to release heat from the high-temperature and high-pressure gaseous mixed working fluid discharged from the ejector assembly through the high-pressure side channel of the first reheater 5, the inlet of the low-pressure side channel of the first reheater 5 is connected to the first branch of the bottom liquid outlet of the front-stage gas-liquid separator 8, and the outlet of the low-pressure side channel of the first reheater 5 is connected to the refrigerant working fluid inlets of the first and second generators 1 and 2 respectively through the first and second working fluid pumps 19 and 21 and the first and second flow regulating valves 20 and 22. The condenser 6 is arranged on the outlet pipeline of the high-pressure side channel of the first reheater 5, and is used to flow the refrigerant working medium after releasing heat through the high-pressure side channel of the first reheater 5 into the condenser 6 to realize partial condensation of the mixed working medium and form a gas-liquid two-phase mixture; the second reheater 7 includes a high-pressure side channel and a low-pressure side channel capable of heat exchange, the outlet of the condenser 6 is connected to the inlet of the high-pressure side channel of the second reheater 7, the outlet of the high-pressure side channel of the second reheater 7 is connected to the refrigerant working medium inlet of the front-stage gas-liquid separator 8, the inlet of the low-pressure side channel of the second reheater 7 is connected to the outlet of the rear-stage partial condenser 18, and the outlet of the low-pressure side channel of the second reheater 7 is connected to the injection fluid inlet of the first ejector 3.

[0047] In this solution, the inlet end of the evaporator assembly is connected to the outlet end of the low-pressure side channel of the second evaporative condenser 14, and the evaporator assembly includes a third regenerator 15, a third throttling component 16 and an evaporator 17, wherein the first side pipe of the third regenerator 15, the third throttling component 16, the evaporator 17, and the second side pipe of the third regenerator 15 are connected in sequence, and the outlet end of the second side pipe of the third regenerator 15 is connected to the injection fluid inlet of the first ejector 3 through the rear-stage partial condenser 18 and the low-pressure side channel of the second regenerator 7.

[0048] In this solution, the hot water pipeline of the solar thermal collector 24 is connected to the heat storage tank 25 and the hot water pump 26 in sequence, and then flows into the first generator 1 and the second generator 2, respectively, to convert the heat energy converted from solar energy into heat for the generators. The refrigerant vapor generated by the first generator 1 enters the first ejector 3 as the working fluid, ejecting the gaseous working fluid rich in low-boiling-point components from the subsequent partial condenser 18 to complete the first stage of pressure increase. The outlet of the first ejector 3 is connected to the ejection fluid inlet of the second ejector 4. The refrigerant vapor generated by the second generator 2 enters the second ejector 4 as the working fluid. In addition to ejecting the intermediate-pressure steam from the outlet of the first ejector 3, it also ejects the intermediate-pressure steam rich in high-boiling-point components from the bottom of the front-stage gas-liquid separator 8 and the rear-stage gas-liquid separator 12, which has been throttled and reduced in pressure by the first throttling component 9 and the second throttling component 13, and then sequentially passed through the front-stage evaporative condenser 10 and the front-stage partial condenser 11 for evaporation and heat absorption, completing the second stage of pressure increase within the second ejector 4. The high-pressure steam at the outlet of the second ejector 4 is cooled through the high-pressure side passage of the first regenerator 5, the condenser 6, and the high-pressure side passage of the second regenerator 7, becoming a gas-liquid two-phase working medium before flowing into the pre-stage gas-liquid separator 8 for flash separation and purification. The gaseous working medium entering the pre-stage gas-liquid separator 8 flows upward through the pre-stage partial condenser 11, undergoing a distillation and purification process. A gaseous mixed working medium rich in low-boiling-point components is obtained at the top of the pre-stage gas-liquid separator 8. The condensed liquid working medium, along with the liquid working medium rich in high-boiling-point components separated by flash evaporation, flows out of the bottom of the pre-stage gas-liquid separator 8. The mixed working medium flowing out of the bottom of the pre-stage gas-liquid separator 8 is split into two paths. One of the paths is as follows: After the liquid mixed working medium flows through the first regenerator 5 to recover heat from the steam at the outlet of the second ejector 4, it is fed into the first generator 1 and the second generator 2 via the first working medium pump 19 and the second working medium pump 21, respectively, to serve as the working fluid for the first ejector 3 and the second ejector 4. The other working medium flow direction is as follows: Part of the liquid-phase mixed working medium flowing out of the bottom of the front-stage gas-liquid separator 8 is throttled and reduced in pressure by the first throttling component 9 to a refrigerant of lower temperature and intermediate pressure, and then flows into a side channel of the front-stage evaporative condenser 10 to provide cooling capacity for the condensation of the gas-phase mixed working medium flowing out of the top of the front-stage gas-liquid separator 8. The gas-liquid two-phase mixture flowing out of the other side channel of the front-stage evaporative condenser 10 enters the rear-stage gas-liquid separator 12 for flash separation, separating it into a gas-phase mixed working medium rich in low-boiling-point components and a liquid-phase mixed working medium rich in high-boiling-point components. The gas-phase working medium entering the rear-stage gas-liquid separator 12 flows from bottom to top through the rear-stage partial condenser 18 to undergo a distillation and purification process, thereby obtaining a saturated gas-phase working medium rich in low-boiling-point components of higher purity, which flows out of the top of the rear-stage gas-liquid separator 12, while the liquid working medium rich in high-boiling-point components flows out of the bottom of the rear-stage gas-liquid separator 12.The liquid mixed working fluid flowing out of the rear-stage gas-liquid separator 12 and part of the liquid mixed working fluid flowing out of the bottom of the front-stage gas-liquid separator 8 realize the step-by-step distillation and step-by-step condensation process of the gas mixed working fluid flashed and separated in the front-stage gas-liquid separator 8 under the intermediate pressure, and then are sucked into the first ejector 4 for a single-stage pressurization process. The gaseous mixed working fluid with a low-boiling-point component content higher than 99.5% flowing out of the rear-stage gas-liquid separator 12 is first condensed into liquid by the rear-stage evaporative condenser 14, and then flows into the third regenerator 15 to become a subcooled liquid. It is throttled and reduced in pressure by the third throttling component 16 to become a low-temperature and low-pressure refrigerant to realize low-temperature refrigeration of -20°C to -80°C in the evaporator 17, thereby completing the first-stage low-temperature cooling capacity utilization, and then enters the third regenerator 15, the rear-stage partial condenser 18 and the second regenerator 7 in sequence to realize the second-stage, third-stage and fourth-stage cascade utilization of cooling capacity. Finally, the formed gaseous working fluid is first sucked into the first ejector 3 to complete the first-stage pressure boosting process, and then sucked into the first ejector 4 to complete the second-stage pressure boosting process, thus completing the whole cycle.

[0049] Example 2

[0050] like Figure 1 As shown, this embodiment provides a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration system, including a first generator 1, a second generator 2, a first ejector 3, a second ejector 4, a first regenerator 5, a condenser 6, a second regenerator 7, a front-stage gas-liquid separator 8, a first throttling component 9, a front-stage evaporative condenser 10, a front-stage partial condenser 11, a rear-stage gas-liquid separator 12, a second throttling component 13, a rear-stage evaporative condenser 14, a third regenerator 15, a third throttling component 16, an evaporator 17, a rear-stage partial condenser 18, a first refrigerant pump 19, a first flow regulating valve 20, a second refrigerant pump 21, a second flow regulating valve 22, a third flow regulating valve 23, a solar collector 24, a heat storage tank 25, a hot water pump 26 and a fourth flow regulating valve 27.

[0051] In this solution, the outlet of the solar collector 24 is connected to the inlet of the heat storage tank 25, and the outlet of the heat storage tank 25 is connected to the inlet of the hot water pump 26. The outlet of the hot water pump 26 is divided into two branches, one of which is connected to the hot water channel inlet of the first generator 1, and the hot water channel outlet of the first generator 1 is connected to the water channel inlet of the solar collector 24 via the third flow regulating valve 23, and the other branch is connected to the hot water channel inlet of the second generator 2, and the hot water channel outlet of the second generator 2 is connected to the water channel inlet of the solar collector 24 via the fourth flow regulating valve 27.

[0052] In this solution, the refrigerant vapor outlet of the first generator 1 is connected to the working fluid inlet of the first ejector 3, the refrigerant vapor outlet of the second generator 2 is connected to the working fluid inlet of the second ejector 4, the outlet of the first ejector 3 is connected to the inlet of the ejection fluid of the second ejector 4, the outlet of the second ejector 4 is connected to the refrigerant inlet of the condenser 6 through the side channel of the first regenerator 5, the refrigerant outlet of the condenser 6 is connected to the high-pressure side channel inlet of the second regenerator 7, the high-pressure side channel outlet of the second regenerator 7 is connected to the working fluid inlet of the front-stage gas-liquid separator 8, and the front-stage gas-liquid separator 8 is also provided with a top The top outlet and the bottom outlet are divided into two branches, one of which is connected to the liquid channel inlet of the first regenerator 5. The liquid channel outlet of the first regenerator 5 is divided into two parallel branches, wherein the first parallel branch is connected to the inlet of the first working fluid pump 19, and the outlet of the first working fluid pump 19 is connected to the refrigerant inlet of the first generator 1 through the first flow regulating valve 20, wherein the second parallel branch is connected to the inlet of the second working fluid pump 21, and the outlet of the second working fluid pump 21 is connected to the refrigerant inlet of the second generator 2 through the second flow regulating valve 22, and the other branch of the bottom outlet of the front-stage gas-liquid separator 8 is connected to the first The inlet of the first throttling component 9 is connected, the outlet of the first throttling component 9 is connected to the inlet of the low-pressure side channel of the front-stage evaporative condenser 10, the top outlet of the front-stage gas-liquid separator 8 is connected to the inlet of the side channel of the front-stage evaporative condenser 10, the outlet of the side channel of the front-stage evaporative condenser 10 is connected to the refrigerant working medium inlet of the rear-stage gas-liquid separator 12, the bottom outlet of the rear-stage gas-liquid separator 12 is connected to the inlet of the second throttling component 13, the outlet of the second throttling component 13 is connected to the inlet of the low-pressure side channel of the rear-stage evaporative condenser 14, and the outlet of the low-pressure side channel of the rear-stage evaporative condenser 14 passes through the The low-pressure side channel is connected to the inlet of the front-stage partial condenser 11, the outlet of the front-stage partial condenser 11 is connected to the induced fluid inlet of the second ejector 4, the top outlet of the rear-stage gas-liquid separator 12, the high-pressure side channel of the rear-stage evaporative condenser 14, the first side channel of the third regenerator 15, the third throttling component 16, and the inlet of the evaporator 17 are connected in series in sequence, the outlet of the evaporator 17 is connected to the inlet of the rear-stage partial condenser 18 through the second side channel of the third regenerator 15, the channels on both sides of the third regenerator 15 realize heat exchange, and the outlet of the rear-stage partial condenser 18 is connected to the induced fluid inlet of the first ejector 3 through the low-pressure side channel of the second regenerator 7.

[0053] In this embodiment, the working fluid inlet of the first ejector 3 is connected to the outlet of the first generator 1, allowing the high-temperature steam generated by the first generator 1 to enter the first ejector 3 as the working fluid. The working fluid is then ejected into a mixed working medium with a low-boiling-point component content exceeding 99.5% from the top of the downstream gas-liquid separator 12. This mixed working medium with a low-boiling-point component content exceeding 99.5% serves as the ejection fluid, undergoing a first-stage pressure boosting process within the first ejector 3 and becoming steam at intermediate pressure. The fluid at the outlet of the first ejector 3 is mixed with the high-boiling-point component-rich gaseous working medium from the upstream partial condenser 11, and then serves as the ejection fluid for the second ejector 4. The fluid undergoes a second-stage pressure boosting process within the second ejector 4 and becomes high-pressure superheated steam. The working fluid inlet of the second ejector 4 is connected to the outlet of the second generator 2, allowing the high-temperature steam generated by the second generator 2 to serve as the working fluid to eject the intermediate-pressure gaseous working medium, thereby boosting the pressure of the mixed working medium to high-pressure superheated steam.

[0054] In this scheme, the superheated mixed refrigerant vapor discharged by the second generator 2 serves as the working fluid of the second ejector 4. In addition to the steam at the intermediate pressure at the outlet of the first ejector 3, two parts of steam are also ejected. The first part of the steam is the steam at the intermediate pressure rich in high-boiling-point components that flows out from the bottom of the front-stage gas-liquid separator 8 and undergoes the throttling and pressure reduction process of the first throttling component 9 and the evaporation and heat absorption process of the front-stage evaporative condenser 10 and the front-stage partial condenser 11. The second part of the steam is the steam at the intermediate pressure rich in high-boiling-point components that flows out from the bottom of the rear-stage gas-liquid separator 12 and undergoes the throttling and pressure reduction process of the second throttling component 13 and the evaporation and heat absorption process of the rear-stage evaporative condenser 14, the front-stage evaporative condenser 10 and the front-stage partial condenser 11.

[0055] In this embodiment, the first reheater 5 includes a high-pressure side channel and a low-pressure side channel that can realize heat exchange. The inlet of the high-pressure side channel of the first reheater 5 is connected to the working fluid outlet of the ejector assembly, and the outlet of the high-pressure side channel of the first reheater 5 is connected to the working fluid inlet of the condenser 6; the inlet of the low-pressure side channel of the first reheater 5 is connected to the bottom liquid outlet of the front-stage gas-liquid separator 8, and the outlet of the low-pressure side channel of the first reheater 5 is connected to the generator inlet through a throttling component.

[0056] In this scheme, the front-stage partial condenser 11 is arranged in the front-stage gas-liquid separator 8 and is located in the upper space, and the rear-stage partial condenser 18 is arranged in the rear-stage gas-liquid separator 12 and is located in the upper space. The mixed working fluid vapor separated by flash evaporation from the front-stage gas-liquid separator 8 is subjected to the first-stage distillation purification process of the low-boiling point component by the front-stage partial condenser 11, and then enters the front-stage condenser evaporator 10 to be condensed into a gas-liquid two-phase mixed working fluid, and then flash-separated by the rear-stage gas-liquid separator 12. The separated mixed working fluid vapor rich in low-boiling point components is subjected to the second-stage distillation purification process by the rear-stage partial condenser 18. The purity of the low-boiling point component entering the evaporator 17 is improved through the cascade distillation effect of two-stage flash separation and two-stage partial condensation purification, thereby achieving the purpose of producing a lower refrigeration temperature.

[0057] In this embodiment, the outlet of the front-stage condenser 11 is connected to the pipeline between the outlet of the first ejector 3 and the inlet of the second ejector 4 for induced fluid, and the low-pressure side outlet of the rear-stage evaporative condenser 14 is connected to the pipeline between the outlet of the first throttling component 9 and the inlet of the low-pressure side of the front-stage evaporative condenser 10.

[0058] In this solution, the working fluid outlet of the second ejector 4 is connected to the high-pressure side channel inlet of the first regenerator 5. The high-temperature and high-pressure gaseous mixed working fluid discharged from the refrigerant working fluid outlet of the second ejector 4 releases heat through the high-pressure side channel of the first regenerator 5, and then flows into the condenser 6 to realize partial condensation of the mixed working fluid and become a gas-liquid two-phase mixture. After the gas-liquid two-phase mixture is cooled by the second regenerator 7, it enters the front-stage gas-liquid separator 8 for flash separation and is separated into a gas-phase mixed working fluid rich in low-boiling-point components and a liquid-phase mixed working fluid rich in high-boiling-point components. The liquid phase working fluid rich in high-boiling-point components flowing out of the bottom outlet of the front-stage gas-liquid separator 8 is divided into two paths, one of which is sent to the first generator 1 and the second generator 2 through the first regenerator 5 to recover the steam heat at the outlet of the second ejector 4, and then respectively sent to the first working fluid pump 19 and the second working fluid pump 21, thereby serving as the working fluid of the first ejector 3 and the second ejector 4; the other path enters the side channel of the front-stage evaporative condenser 10 after throttling and reducing the pressure through the first throttling component 9, and the saturated gaseous working fluid flowing out of the side channel of the front-stage evaporative condenser 10 enters the front-stage partial condenser 11 to realize the distillation and purification of the gaseous working fluid in the front-stage gas-liquid separator 8. After the gaseous working fluid flowing out of the front-stage partial condenser 11 is mixed with the gaseous working fluid flowing out of the first ejector 3, it is used as the induced fluid in the second ejector 4 to complete the second-stage pressurization process. The gas phase mixed working medium rich in low boiling point components at the top outlet of the front stage gas-liquid separator 8 enters the other side channel of the front stage evaporative condenser 10 and is condensed into a gas-liquid two-phase mixed working medium, and then enters the rear stage gas-liquid separator 12 for flash separation.

[0059] In this embodiment, the flash separation in the post-stage gas-liquid separator 12 separates the gas into a gaseous mixed working fluid rich in low-boiling-point components and a liquid mixed working fluid rich in high-boiling-point components. The liquid mixed working fluid exiting the post-stage gas-liquid separator 12 is throttled and depressurized by the second throttling component 13 before flowing into the low-pressure side channel of the post-stage evaporative condenser 14, where it mixes with the liquid mixed working fluid exiting the bottom of the first gas-liquid separator 8. The gas-phase mixed working fluid with a low boiling point component content higher than 99.5% flowing out of the rear-stage gas-liquid separator 12 first passes through the rear-stage evaporative condenser 14 and absorbs heat through the liquid-phase working fluid flowing out of the bottom of the rear-stage gas-liquid separator 12 to be condensed into liquid, then flows into the third regenerator 15 to become a subcooled liquid, and is throttled and reduced in pressure by the third throttling component 16 to become a low-temperature low-pressure refrigerant to achieve low-temperature refrigeration of -20°C to -80°C in the evaporator 17, thereby completing the first-stage low-temperature cold capacity utilization, and then enters the third regenerator 15, the rear-stage partial condenser 18 and the second regenerator 7 in sequence to achieve the second-stage, third-stage and fourth-stage cascade utilization of cold capacity; the gas-phase mixed working fluid with a low boiling point component content higher than 99.5% flowing out of the top of the rear-stage gas-liquid separator 12 is condensed into a liquid to achieve cascade utilization and cascade rectification of cold capacity at a low evaporation pressure, and the formed gas-phase working fluid is first sucked into the first ejector 3 to complete the first-stage pressure boosting process, and then sucked into the first ejector 4 to complete the second-stage pressure boosting process.

[0060] In this solution, the liquid-phase mixed working medium flowing out of the bottom of the front-stage gas-liquid separator 8 is throttled and reduced in pressure by the first throttling component 9 to become a refrigerant with a lower temperature and intermediate pressure, and flows into the front-stage evaporative condenser 10 and the front-stage partial condenser 11 in sequence for cascade utilization. The liquid-phase mixed working medium flowing out of the bottom of the rear-stage gas-liquid separator 12 is throttled and reduced in pressure by the second throttling component 13 to become a refrigerant with a lower temperature and intermediate pressure, and flows into the rear-stage evaporative condenser 14, the front-stage evaporative condenser 10 and the front-stage partial condenser 11 in sequence for three-stage utilization. After part of the liquid-phase mixed working medium flowing out of the bottom of the front-stage gas-liquid separator 8 and the liquid-phase mixed working medium flowing out of the rear-stage gas-liquid separator 12 are combined, a cascade distillation and cascade condensation process of the gas-phase mixed working medium flashed and separated in the front-stage gas-liquid separator 8 is realized at an intermediate pressure, and then the gas-phase mixed working medium is sucked into the first ejector 4 for a single-stage pressure boosting process.

[0061] In this embodiment, the function of the front-stage gas-liquid separator 8 is to separate the high-temperature and high-pressure gas-liquid two-phase mixed working fluid from the second regenerator 7 into a gas-phase mixed working fluid containing low-boiling-point components flowing out from its top working fluid outlet and a liquid-phase mixed working fluid containing high-boiling-point components flowing out from its bottom working fluid outlet. A front-stage partial condenser 11 is provided at the top of the front-stage gas-liquid separator 8. The front-stage partial condenser 11 partially condenses the gas-phase working fluid containing low-boiling-point components separated by the front-stage gas-liquid separator 8, thereby obtaining a saturated gas-phase working fluid rich in high-purity low-boiling-point components at the top outlet of the front-stage gas-liquid separator 8, wherein the condensed liquid working fluid refluxes to the bottom of the front-stage gas-liquid separator 8, and flows out from the bottom of the front-stage gas-liquid separator 8 together with the liquid-phase working fluid containing high-boiling-point components separated by flash evaporation.

[0062] In this embodiment, the function of the rear-stage gas-liquid separator 12 is to separate the gas-liquid mixture from the front-stage evaporative condenser 10 into a gas-phase working fluid rich in low-boiling-point components flowing out from its top working fluid outlet and a liquid-phase working fluid rich in high-boiling-point components flowing out from its bottom working fluid outlet. A rear-stage partial condenser 18 is provided on the top of the rear-stage gas-liquid separator 12. The rear-stage partial condenser 18 partially condenses the gas-phase working fluid rich in low-boiling-point components separated by the front-stage gas-liquid separator 12, thereby obtaining a saturated gas-phase working fluid at the top outlet of the rear-stage gas-liquid separator 12, wherein the condensed liquid working fluid refluxes to the bottom of the rear-stage gas-liquid separator 12, and flows out from the bottom of the rear-stage gas-liquid separator 12 together with the liquid-phase working fluid rich in high-boiling-point components separated by flash evaporation.

[0063] Example 3

[0064] This embodiment provides a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration system, including a first generator 1, a second generator 2, a first ejector 3, a second ejector 4, a first reheater 5, a condenser 6, a second reheater 7, a front-stage gas-liquid separator 8, a first throttling component 9, a front-stage evaporative condenser 10, a front-stage partial condenser 11, a rear-stage gas-liquid separator 12, a second throttling component 13, a rear-stage evaporative condenser 14, a third reheater 15, a third throttling component 16, an evaporator 17, a rear-stage partial condenser 18, a first refrigerant pump 19, a first flow regulating valve 20, a second refrigerant pump 21, a second flow regulating valve 22, a third flow regulating valve 23, a solar collector 24, a heat storage tank 25, a hot water pump 26 and a fourth flow regulating valve 27.

[0065] For the sake of brevity, in the description of this embodiment, the same technical features as those in Example 2 are not described again, and only the differences between this embodiment and Example 2 are described. The differences between this embodiment and Example 2 are as follows: Figure 2As shown, part of the liquid working medium flowing out of the bottom of the front-stage gas-liquid separator 8 is throttled and depressurized by the first throttling component 9, and then mixed with the liquid working medium rich in high-boiling-point components flowing out of the bottom of the rear-stage gas-liquid separator 12. The mixed working medium flows through the front-stage evaporative condenser 10 and the front-stage partial condenser 11, and the gas phase mixed working medium flashed and separated in the front-stage gas-liquid separator 8 is subjected to a stepwise distillation and stepwise condensation process at an intermediate pressure. The intermediate-pressure mixed working medium rich in high-boiling-point components at the outlet of the front-stage partial condenser 11 flows directly into the second ejector 4 as an ejector fluid to achieve a pressure increase process in the second ejector 4. In addition, the refrigerant vapors obtained at the outlets of the first ejector 3 and the second ejector 4 are mixed, passed through the first regenerator 5, and then flow into the condenser 6 to achieve partial condensation of the mixed working medium and form a gas-liquid two-phase mixture.

[0066] Example 4

[0067] The present invention provides a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration system, comprising a first generator 1, a first ejector 3, a second ejector 4, a first regenerator 5, a condenser 6, a second regenerator 7, a front-stage gas-liquid separator 8, a first throttling component 9, a front-stage evaporative condenser 10, a front-stage partial condenser 11, a rear-stage gas-liquid separator 12, a second throttling component 13, a rear-stage evaporative condenser 14, a third regenerator 15, a third throttling component 16, an evaporator 17, a rear-stage partial condenser 18, a first refrigerant pump 19, a first flow regulating valve 20, a third flow regulating valve 23, a solar collector 24, a heat storage tank 25 and a hot water pump 26.

[0068] For the sake of brevity, in the description of this embodiment, the same technical features as those in Example 2 are not described again, and only the differences between this embodiment and Example 2 are described. The differences between this embodiment and Example 2 are as follows: Figure 3 As shown, this embodiment utilizes only a single generator to absorb the heat released by the solar thermal collection unit. The refrigerant vapor outlet of the first generator 1 is divided into two branches, one connected to the working fluid inlet of the first ejector 3, and the other connected to the working fluid inlet of the second ejector 4. The intermediate-pressure steam obtained at the outlet of the first ejector 3 is mixed with the intermediate-pressure steam enriched in high-boiling-point components flowing out of the outlet of the pre-stage partial condenser 11 to serve as the injection fluid for the second ejector 4. After undergoing the second-stage pressure boosting process of the second ejector 4, it becomes high-pressure superheated steam. Furthermore, a portion of the liquid-phase mixed working fluid flowing out of the bottom of the pre-stage gas-liquid separator 8 is transported to the first regenerator 5 to recover the steam heat at the working fluid outlet of the second ejector 4. The steam is then fed into the first generator 1 via the first working fluid pump 19 and the first flow control valve 20 for heat absorption.

[0069] Example 5

[0070] This embodiment provides a solar-driven mixed refrigerant two-stage separation low-temperature refrigeration system, including a first generator 1, a first ejector 3, a second ejector 4, a first regenerator 5, a condenser 6, a second regenerator 7, a front-stage gas-liquid separator 8, a first throttling component 9, a front-stage evaporative condenser 10, a front-stage partial condenser 11, a rear-stage gas-liquid separator 12, a second throttling component 13, a rear-stage evaporative condenser 14, a third regenerator 15, a third throttling component 16, an evaporator 17, a rear-stage partial condenser 18, a first refrigerant pump 19, a first flow regulating valve 20, a third flow regulating valve 23, a solar collector 24, a heat storage tank 25 and a hot water pump 26.

[0071] For the sake of brevity, in the description of this embodiment, the same technical features as those in Example 2 are not described again, and only the differences between this embodiment and Example 2 are described. The differences between this embodiment and Example 2 are as follows: Figure 4 As shown, this embodiment utilizes only a single generator to absorb the heat released by the solar thermal collection unit. The refrigerant vapor outlet of the first generator 1 is divided into two branches, one connected to the working fluid inlet of the first ejector 3, and the other connected to the working fluid inlet of the second ejector 4. The liquid refrigerant flowing out of the bottom of the pre-stage gas-liquid separator 8 is mixed with the liquid refrigerant rich in high-boiling-point components flowing out of the bottom of the post-stage gas-liquid separator 12. The mixture then flows through the pre-stage evaporative condenser 10 and the pre-stage partial condenser 11, where it undergoes an evaporation and heat absorption process to produce a mixed refrigerant rich in high-boiling-point components at an intermediate pressure. This mixed refrigerant then flows directly into the second ejector 4 as the ejector fluid, achieving a second-stage pressure increase within the second ejector 4. The high-pressure refrigerant vapors obtained from the outlets of the first and second ejectors 3 and 4 are mixed, cooled in the first regenerator 5, and then enter the condenser 6, where the mixed refrigerant is partially condensed to form a gas-liquid two-phase mixture. In addition, part of the liquid mixed working fluid flowing out from the bottom of the front-stage gas-liquid separator 8 is sent to the first generator 1 through the first working fluid pump 19 and the first flow regulating valve 20 to absorb heat after recovering the steam heat at the outlet of the first ejector 3 and the second ejector 4 through the first regenerator 5.

[0072] The working fluid used in the refrigeration system in the above embodiment is a binary or more non-azeotropic mixture of a high-boiling-point working fluid and a low-boiling-point working fluid, wherein the low-boiling-point working fluid is an HC or HFC-type working fluid such as R32, R290, R170, and R23, and the high-boiling-point working fluid is an HC or HFC-type working fluid such as R134a, R152a, R600, and R600a.

[0073] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0074] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

[0075] The above-described embodiments merely represent several implementation methods of the present invention, and their description is relatively detailed, but they should not be construed as limiting the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method, characterized by: Here are the steps: The high-temperature steam generated by the first generator enters the first ejector as the working fluid, and the first ejector ejects the gaseous working medium from the rear-stage partial condenser. The outlet fluid of the first ejector is mixed with the gaseous working medium rich in high-boiling-point components from the front-stage partial condenser and serves as the ejection fluid of the second ejector. After the second-stage pressure-boosting process of the second ejector, it becomes high-pressure superheated steam. The high-temperature steam generated by the second generator serves as the working fluid of the second ejector. The outlet fluid of the second ejector is cooled by the condenser and enters the front-stage gas-liquid separator. A portion of the liquid at the bottom of the front-stage gas-liquid separator is respectively fed into the first generator and the second generator via the first working fluid pump and the second working fluid pump, and the other portion is throttled and depressurized by the first throttling component and then enters the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser; a front-stage partial condenser is provided above the internal liquid level of the front-stage gas-liquid separator, and the front-stage partial condenser is used to perform a rectification and purification process on the mixed working fluid vapor separated by flash evaporation of the front-stage gas-liquid separator; the gas phase mixed working fluid flowing out of the top of the front-stage gas-liquid separator passes through the high-pressure side channel of the front-stage evaporative condenser and enters the rear-stage gas-liquid separator for flash separation; A rear-stage partial condenser is provided above the internal liquid level of the rear-stage gas-liquid separator, and the rear-stage partial condenser is used for distilling and purifying the mixed working fluid vapor rich in low-boiling point components separated by the rear-stage gas-liquid separator; the liquid-phase mixed working fluid flowing out of the rear-stage gas-liquid separator passes through the throttling and pressure reduction process of the second throttling component, and then passes through the rear-stage evaporative condenser to absorb heat and mix with the working fluid throttled by the first throttling component, and then enters the low-pressure side channel of the front-stage evaporative condenser together; the gaseous working fluid flowing out from the top of the rear-stage gas-liquid separator is condensed into liquid through the rear-stage evaporative condenser, and is throttled and pressure-reduced into low-temperature and low-pressure refrigerant through the third throttling component to realize low-temperature refrigeration in the evaporator, and then enters the rear-stage partial condenser.

2. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 1, characterized in that: The high-pressure superheated refrigerant vapor discharged from the second ejector is cooled by the first reheater and then enters the condenser to realize partial condensation of the mixed working fluid to form a gas-liquid two-phase mixture. The gas-liquid two-phase mixture flows into the second reheater and is further cooled so that the low-boiling point component in the gas phase is partially condensed into liquid, and enters the front-stage gas-liquid separator for a first-stage flash separation; a part of the liquid at the bottom of the front-stage gas-liquid separator first passes through the first reheater to absorb heat, and then is respectively sent to the first generator and the second generator through the first working fluid pump and the second working fluid pump; the gas working fluid from the rear-stage partial condenser first passes through the second reheater to absorb heat and then serves as the injection fluid of the first ejector.

3. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 1, characterized in that: The working medium condensed into liquid by the subsequent evaporative condenser passes through the first side channel of the third regenerator, the third throttling component, the evaporator, the second side channel of the third regenerator in sequence, and enters the subsequent partial condenser.

4. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method, characterized by: Here are the steps: The high-temperature steam generated by the first generator enters the first ejector as the working fluid, and the first ejector ejects the gaseous working medium from the rear-stage partial condenser. The gaseous working medium rich in high-boiling-point components from the front-stage partial condenser serves as the ejection fluid of the second ejector, which is pressurized by the second ejector to become high-pressure superheated steam. The high-temperature steam generated by the second generator serves as the working fluid of the second ejector. The outlet fluids of the first ejector and the second ejector are cooled by the condenser and then enter the front-stage gas-liquid separator. A portion of the liquid at the bottom of the front-stage gas-liquid separator is respectively fed into the first generator and the second generator via the first working fluid pump and the second working fluid pump, and the other portion is throttled and depressurized by the first throttling component and then enters the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser; a front-stage partial condenser is provided above the internal liquid level of the front-stage gas-liquid separator, and the front-stage partial condenser is used to perform a rectification and purification process on the mixed working fluid vapor separated by flash evaporation of the front-stage gas-liquid separator; the gas phase mixed working fluid flowing out of the top of the front-stage gas-liquid separator passes through the high-pressure side channel of the front-stage evaporative condenser and enters the rear-stage gas-liquid separator for flash separation; A rear-stage partial condenser is provided above the internal liquid level of the rear-stage gas-liquid separator, and the rear-stage partial condenser is used for distilling and purifying the mixed working fluid vapor rich in low-boiling point components separated by the rear-stage gas-liquid separator; the liquid-phase mixed working fluid flowing out of the rear-stage gas-liquid separator passes through the throttling and pressure reduction process of the second throttling component, and then passes through the rear-stage evaporative condenser to absorb heat and mix with the working fluid throttled by the first throttling component, and then enters the low-pressure side channel of the front-stage evaporative condenser together; the gaseous working fluid flowing out from the top of the rear-stage gas-liquid separator is condensed into liquid through the rear-stage evaporative condenser, and is throttled and pressure-reduced into low-temperature and low-pressure refrigerant through the third throttling component to realize low-temperature refrigeration in the evaporator, and then enters the rear-stage partial condenser.

5. The solar-driven mixed working medium two-stage separation low-temperature refrigeration method according to claim 4 is characterized in that: The high-pressure superheated refrigerant vapor discharged by the first ejector and the second ejector is cooled by the first reheater and then enters the condenser to realize partial condensation of the mixed working fluid to form a gas-liquid two-phase mixture. The gas-liquid two-phase mixture flows into the second reheater and is further cooled so that the low-boiling point component in the gas phase is partially condensed into liquid, and enters the front-stage gas-liquid separator for primary flash separation; a part of the liquid at the bottom of the front-stage gas-liquid separator first passes through the first reheater to absorb heat, and then is respectively sent to the first generator and the second generator through the first working fluid pump and the second working fluid pump; the gas working fluid from the rear-stage partial condenser first passes through the second reheater to absorb heat and then serves as the injection fluid of the first ejector.

6. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 4, characterized in that: The working medium condensed into liquid by the subsequent evaporative condenser passes through the first side channel of the third regenerator, the third throttling component, the evaporator, the second side channel of the third regenerator in sequence, and enters the subsequent partial condenser.

7. The solar-driven mixed working medium two-stage separation low-temperature refrigeration method according to any one of claims 1 to 6, characterized in that: The solar collector, heat storage tank and hot water pump are connected in sequence to form a circulation loop, which is connected to the inlet and outlet of the heating channels of the first generator and the second generator, and is used to use the heat energy converted from solar energy to heat the refrigerant working medium of the generator into refrigerant vapor for discharge.

8. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method, characterized by: Here are the steps: The high-temperature steam generated by the first generator is used as the working fluid to enter the first ejector and the second ejector respectively. The first ejector ejects the gaseous working medium from the rear-stage partial condenser. The outlet fluid of the first ejector is mixed with the gaseous working medium rich in high-boiling-point components from the front-stage partial condenser and serves as the ejection fluid of the second ejector. After the second-stage pressure-boosting process of the second ejector, it becomes high-pressure superheated steam. The outlet fluid of the second ejector is cooled by the condenser and then enters the front-stage gas-liquid separator. A portion of the liquid at the bottom of the front-stage gas-liquid separator is pumped into the first generator via the first working fluid pump, and the other portion is throttled and depressurized by the first throttling component and then enters the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser; a front-stage partial condenser is provided above the internal liquid level of the front-stage gas-liquid separator, and the front-stage partial condenser is used to perform a rectification and purification process on the mixed working fluid vapor separated by flash evaporation of the front-stage gas-liquid separator; the gas phase mixed working fluid flowing out of the top of the front-stage gas-liquid separator passes through the high-pressure side channel of the front-stage evaporative condenser and enters the rear-stage gas-liquid separator for flash separation; A rear-stage partial condenser is provided above the internal liquid level of the rear-stage gas-liquid separator, and the rear-stage partial condenser is used for distilling and purifying the mixed working fluid vapor rich in low-boiling point components separated by the rear-stage gas-liquid separator; the liquid-phase mixed working fluid flowing out of the rear-stage gas-liquid separator passes through the throttling and pressure reduction process of the second throttling component, and then passes through the rear-stage evaporative condenser to absorb heat and mix with the working fluid throttled by the first throttling component, and then enters the low-pressure side channel of the front-stage evaporative condenser together; the gaseous working fluid flowing out from the top of the rear-stage gas-liquid separator is condensed into liquid through the rear-stage evaporative condenser, and is throttled and pressure-reduced into low-temperature and low-pressure refrigerant through the third throttling component to realize low-temperature refrigeration in the evaporator, and then enters the rear-stage partial condenser.

9. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 8, characterized in that: The high-pressure superheated refrigerant vapor discharged from the second ejector is cooled by the first reheater and then enters the condenser to realize partial condensation of the mixed working fluid to form a gas-liquid two-phase mixture. The gas-liquid two-phase mixture flows into the second reheater and is further cooled so that the low-boiling point component in the gas phase is partially condensed into liquid, and enters the front-stage gas-liquid separator for a first-stage flash separation; a part of the liquid at the bottom of the front-stage gas-liquid separator first passes through the first reheater to absorb heat, and then is pumped into the first generator through the first working fluid pump; the gas working fluid from the rear-stage partial condenser first passes through the second reheater to absorb heat and then serves as the injection fluid of the first ejector.

10. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 8, characterized in that: The working medium condensed into liquid by the subsequent evaporative condenser passes through the first side channel of the third regenerator, the third throttling component, the evaporator, the second side channel of the third regenerator in sequence, and enters the subsequent partial condenser.

11. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method, characterized by: Here are the steps: The high-temperature steam generated by the first generator serves as the working fluid and enters the first ejector and the second ejector respectively. The first ejector ejects the gaseous working medium from the rear-stage partial condenser, and the gaseous working medium rich in high-boiling-point components from the front-stage partial condenser serves as the ejection fluid of the second ejector. The gaseous working medium is pressurized by the second ejector to become high-pressure superheated steam. The outlet fluids of the first ejector and the second ejector are cooled by the condenser and then enter the front-stage gas-liquid separator. A portion of the liquid at the bottom of the front-stage gas-liquid separator is pumped into the first generator via the first working fluid pump, and the other portion is throttled and depressurized by the first throttling component and then enters the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser; a front-stage partial condenser is provided above the internal liquid level of the front-stage gas-liquid separator, and the front-stage partial condenser is used to perform a rectification and purification process on the mixed working fluid vapor separated by flash evaporation of the front-stage gas-liquid separator; the gas phase mixed working fluid flowing out of the top of the front-stage gas-liquid separator passes through the high-pressure side channel of the front-stage evaporative condenser and enters the rear-stage gas-liquid separator for flash separation; A rear-stage partial condenser is provided above the internal liquid level of the rear-stage gas-liquid separator, and the rear-stage partial condenser is used for distilling and purifying the mixed working fluid vapor rich in low-boiling point components separated by the rear-stage gas-liquid separator; the liquid-phase mixed working fluid flowing out of the rear-stage gas-liquid separator passes through the throttling and pressure reduction process of the second throttling component, and then passes through the rear-stage evaporative condenser to absorb heat and mix with the working fluid throttled by the first throttling component, and then enters the low-pressure side channel of the front-stage evaporative condenser together; the gaseous working fluid flowing out from the top of the rear-stage gas-liquid separator is condensed into liquid through the rear-stage evaporative condenser, and is throttled and pressure-reduced into low-temperature and low-pressure refrigerant through the third throttling component to realize low-temperature refrigeration in the evaporator, and then enters the rear-stage partial condenser.

12. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 11, characterized in that: The high-pressure superheated refrigerant vapor discharged by the first ejector and the second ejector is cooled by the first reheater and then enters the condenser to realize partial condensation of the mixed working fluid to form a gas-liquid two-phase mixture. The gas-liquid two-phase mixture flows into the second reheater and is further cooled so that the low-boiling point component in the gas phase is partially condensed into liquid, and enters the front-stage gas-liquid separator for primary flash separation; a part of the liquid at the bottom of the front-stage gas-liquid separator first passes through the first reheater to absorb heat, and then is pumped into the first generator through the first working fluid pump; the gas working fluid from the rear-stage partial condenser first passes through the second reheater to absorb heat and then serves as the injection fluid of the first ejector.

13. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration method according to claim 11, characterized in that: The working medium condensed into liquid by the subsequent evaporative condenser passes through the first side channel of the third regenerator, the third throttling component, the evaporator, the second side channel of the third regenerator in sequence, and enters the subsequent partial condenser.

14. The solar-driven mixed working medium two-stage separation low-temperature refrigeration method according to any one of claims 8 to 13, characterized in that: The solar collector, heat storage tank and hot water pump are connected in sequence to form a circulation loop, which is connected to the inlet and outlet of the heating channel of the first generator and is used to use the heat energy converted from solar energy to heat the refrigerant working medium of the generator into refrigerant vapor for discharge.

15. Solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system, characterized by: The utility model comprises a first generator, a second generator, a first ejector, a second ejector, a condenser, a front-stage gas-liquid separator, a first throttling component, a front-stage partial condenser, a front-stage evaporative condenser, a rear-stage gas-liquid separator, a second throttling component, a rear-stage partial condenser, a rear-stage evaporative condenser, a third throttling component, and an evaporator. The refrigerant vapor outlet of the first generator is connected to the working fluid inlet of the first ejector, the refrigerant vapor outlet of the second generator is connected to the working fluid inlet of the second ejector, the first ejector outlet is connected to the inlet of the ejection fluid of the second ejector, the outlet of the second ejector is connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the working medium inlet of the front-stage gas-liquid separator, the front-stage gas-liquid separator is also provided with a top outlet and a bottom outlet, and the bottom outlet thereof is divided into two branches, one of which is divided into two parallel branches, wherein the first parallel branch is connected to the refrigerant inlet of the first generator, wherein the second parallel branch is connected to the refrigerant inlet of the second generator, and the other branch of the bottom outlet of the front-stage gas-liquid separator is connected to the second parallel branch. The first throttling component is connected to an inlet of a throttling component, an outlet of the first throttling component is connected to an inlet of a low-pressure side channel of a front-stage evaporative condenser, a top outlet of the front-stage gas-liquid separator is connected to an inlet of a high-pressure side channel of the front-stage evaporative condenser, an outlet of the high-pressure side channel of the front-stage evaporative condenser is connected to an inlet of a refrigerant working medium of a rear-stage gas-liquid separator, a bottom outlet of the rear-stage gas-liquid separator is connected to an inlet of a second throttling component, an outlet of the second throttling component is connected to an inlet of a low-pressure side channel of a rear-stage evaporative condenser, an outlet of the low-pressure side channel of the rear-stage evaporative condenser is connected to an inlet of a front-stage partial condenser through a low-pressure side channel of the front-stage evaporative condenser, an outlet of the front-stage partial condenser is connected to an inlet of an ejector fluid, the top outlet of the rear-stage gas-liquid separator, the high-pressure side channel of the rear-stage evaporative condenser, the third throttling component, and an inlet of the evaporator are connected in series in sequence, an outlet of the evaporator is connected to an inlet of a rear-stage partial condenser, and an outlet of the rear-stage partial condenser is connected to an inlet of an ejector fluid. The front-stage partial condenser is arranged above an internal liquid level of the front-stage gas-liquid separator, and a rear-stage partial condenser is arranged above an internal liquid level of the rear-stage gas-liquid separator.

16. Solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system, characterized by: The utility model comprises a first generator, a second generator, a first ejector, a second ejector, a condenser, a front-stage gas-liquid separator, a first throttling component, a front-stage partial condenser, a front-stage evaporative condenser, a rear-stage gas-liquid separator, a second throttling component, a rear-stage partial condenser, a rear-stage evaporative condenser, a third throttling component and an evaporator. The refrigerant vapor outlet of the first generator is connected to the working fluid inlet of the first ejector, the refrigerant vapor outlet of the second generator is connected to the working fluid inlet of the second ejector, the outlet of the first ejector and the outlet of the second ejector are both connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the working medium inlet of the front-stage gas-liquid separator, the front-stage gas-liquid separator is also provided with a top outlet and a bottom outlet, and the bottom outlet thereof is divided into two branches, one of which is divided into two parallel branches, wherein the first parallel branch is connected to the refrigerant inlet of the first generator, wherein the second parallel branch is connected to the refrigerant inlet of the second generator, and the other branch of the bottom outlet of the front-stage gas-liquid separator is parallel to the inlet of the first throttling component. The outlet of the first throttling component is connected to the inlet of the low-pressure side channel of the front-stage evaporative condenser, the top outlet of the front-stage gas-liquid separator is connected to the inlet of the high-pressure side channel of the front-stage evaporative condenser, the outlet of the high-pressure side channel of the front-stage evaporative condenser is connected to the refrigerant working medium inlet of the rear-stage gas-liquid separator, the bottom outlet of the rear-stage gas-liquid separator is connected to the inlet of the second throttling component, the outlet of the second throttling component is connected to the inlet of the low-pressure side channel of the rear-stage evaporative condenser, the outlet of the low-pressure side channel of the rear-stage evaporative condenser is connected to the inlet of the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser, the outlet of the front-stage partial condenser is connected to the inlet of the second ejector induced fluid, the top outlet of the rear-stage gas-liquid separator, the high-pressure side channel of the rear-stage evaporative condenser, the third throttling component, and the evaporator inlet are connected in series in sequence, the evaporator outlet is connected to the inlet of the rear-stage partial condenser, and the outlet of the rear-stage partial condenser is connected to the inlet of the first ejector induced fluid; the front-stage partial condenser is arranged above the internal liquid level of the front-stage gas-liquid separator, and the rear-stage partial condenser is arranged above the internal liquid level of the rear-stage gas-liquid separator.

17. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system, characterized by: The utility model comprises a first generator, a first ejector, a second ejector, a condenser, a front-stage gas-liquid separator, a first throttling component, a front-stage partial condenser, a front-stage evaporative condenser, a rear-stage gas-liquid separator, a second throttling component, a rear-stage partial condenser, a rear-stage evaporative condenser, a third throttling component and an evaporator. The refrigerant vapor outlet of the first generator is respectively connected to the working fluid inlets of the first and second ejectors, the outlet of the first ejector is connected to the inlet of the ejection fluid of the second ejector, the outlet of the second ejector is connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the working fluid inlet of the front-stage gas-liquid separator, the front-stage gas-liquid separator is further provided with a top outlet and a bottom outlet, the bottom outlet of which is divided into two branches, one of which is connected to the refrigerant inlet of the first generator, the other branch of the bottom outlet of the front-stage gas-liquid separator is connected to the inlet of the first throttling component, and the outlet of the first throttling component is connected to the inlet of the low-pressure side channel of the front-stage evaporative condenser. The top outlet of the front-stage gas-liquid separator is connected with the inlet of the high-pressure side channel of the front-stage evaporative condenser, the high-pressure side channel outlet of the front-stage evaporative condenser is connected with the refrigerant working medium inlet of the rear-stage gas-liquid separator, the bottom outlet of the rear-stage gas-liquid separator is connected with the inlet of the second throttling component, the outlet of the second throttling component is connected with the inlet of the low-pressure side channel of the rear-stage evaporative condenser, the outlet of the low-pressure side channel of the rear-stage evaporative condenser is connected with the inlet of the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser, the outlet of the front-stage partial condenser is connected with the inlet of the second ejector induced fluid, the top outlet of the rear-stage gas-liquid separator, the high-pressure side channel of the rear-stage evaporative condenser, the third throttling component, and the evaporator inlet are connected in series in sequence, the evaporator outlet is connected with the inlet of the rear-stage partial condenser, and the outlet of the rear-stage partial condenser is connected with the inlet of the first ejector induced fluid; the front-stage partial condenser is arranged above the internal liquid level of the front-stage gas-liquid separator, and the rear-stage partial condenser is arranged above the internal liquid level of the rear-stage gas-liquid separator.

18. A solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system, characterized by: The utility model comprises a first generator, a first ejector, a second ejector, a condenser, a front-stage gas-liquid separator, a first throttling component, a front-stage partial condenser, a front-stage evaporative condenser, a rear-stage gas-liquid separator, a second throttling component, a rear-stage partial condenser, a rear-stage evaporative condenser, a third throttling component and an evaporator. The refrigerant vapor outlet of the first generator is respectively connected to the working fluid inlets of the first and second ejectors, the outlet of the first ejector and the outlet of the second ejector are both connected to the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is connected to the working fluid inlet of the front-stage gas-liquid separator, the front-stage gas-liquid separator is also provided with a top outlet and a bottom outlet, and the bottom outlet is divided into two branches, one of which is connected to the refrigerant inlet of the first generator, the other branch of the bottom outlet of the front-stage gas-liquid separator is connected to the inlet of the first throttling component, the outlet of the first throttling component is connected to the inlet of the low-pressure side channel of the front-stage evaporative condenser, and the front-stage gas-liquid separator The top outlet is connected with the inlet of the high-pressure side channel of the front-stage evaporative condenser, the high-pressure side channel outlet of the front-stage evaporative condenser is connected with the refrigerant working medium inlet of the rear-stage gas-liquid separator, the bottom outlet of the rear-stage gas-liquid separator is connected with the inlet of the second throttling component, the outlet of the second throttling component is connected with the inlet of the low-pressure side channel of the rear-stage evaporative condenser, the outlet of the low-pressure side channel of the rear-stage evaporative condenser is connected with the inlet of the front-stage partial condenser through the low-pressure side channel of the front-stage evaporative condenser, the outlet of the front-stage partial condenser is connected with the inlet of the second ejector induced fluid, the top outlet of the rear-stage gas-liquid separator, the high-pressure side channel of the rear-stage evaporative condenser, the third throttling component, and the evaporator inlet are connected in series in sequence, the evaporator outlet is connected with the inlet of the rear-stage partial condenser, and the outlet of the rear-stage partial condenser is connected with the inlet of the first ejector induced fluid; the front-stage partial condenser is arranged above the internal liquid level of the front-stage gas-liquid separator, and the rear-stage partial condenser is arranged above the internal liquid level of the rear-stage gas-liquid separator.

19. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system according to claim 15 or 17, characterized in that: It also includes a first regenerator and a second regenerator. The first regenerator is used for heat exchange between the refrigerant working medium in the first branch of the bottom liquid outlet of the front-stage gas-liquid separator and the working medium at the outlet of the second ejector; the second regenerator is used for heat exchange between the gas-liquid two-phase mixture discharged from the condenser and the refrigerant working medium discharged from the rear-stage condenser.

20. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system according to claim 16 or 18, characterized in that: It also includes a first regenerator and a second regenerator. The first regenerator is used for heat exchange between the refrigerant working medium in the first branch of the bottom liquid outlet of the front-stage gas-liquid separator and the working medium at the outlet of the first and second ejectors; the second regenerator is used for heat exchange between the gas-liquid two-phase mixture discharged from the condenser and the refrigerant working medium discharged from the rear-stage condenser.

21. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system according to claim 15 or 16, characterized in that: It also includes a solar thermal collection unit, which includes a solar thermal collector, a heat storage tank and a hot water pump. The solar thermal collector, heat storage tank and hot water pump are connected in sequence to form a circulation loop. The circulation loop is connected to the inlet and outlet of the heating channel of the generator, and is used to use the heat energy converted from solar energy to heat the refrigerant working fluid of the first and second generators into refrigerant vapor for discharge. The working fluid outlets of the first and second generators are correspondingly connected to the working fluid inlets of the first and second ejectors.

22. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system according to claim 17 or 18, characterized in that: It also includes a solar thermal collection unit, which includes a solar thermal collector, a heat storage tank and a hot water pump. The solar thermal collector, heat storage tank and hot water pump are connected in sequence to form a circulation loop. The circulation loop is connected to the inlet and outlet of the heating channel of the generator, and is used to use the heat energy converted from solar energy to heat the refrigerant working fluid of the first generator into refrigerant vapor for discharge. The working fluid outlet of the first generator is respectively connected to the working fluid inlets of the first and second ejectors.

23. The solar-driven mixed-refrigerant two-stage separation low-temperature refrigeration system according to any one of claims 15 to 18, characterized in that: It also includes a third regenerator, the top outlet of the rear-stage gas-liquid separator, the high-pressure side channel of the rear-stage evaporative condenser, the first side channel of the third regenerator, the third throttling component, and the evaporator inlet are connected in series in sequence, the evaporator outlet is connected to the inlet of the rear-stage partial condenser through the second side channel of the third regenerator, and heat exchange is achieved through the channels on both sides of the third regenerator.

Images