CN211575597U

CN211575597U - Solar energy absorbs and penetrates compound transcritical CO2 refrigerating system of penetrating

Info

Publication number: CN211575597U
Application number: CN202020135779.9U
Authority: CN
Inventors: 代宝民; 窦萬斌; 冯一宁; 钱家宝; 郝云樱; 曹钰; 杨海宁
Original assignee: Tianjin University of Commerce
Current assignee: Tianjin University of Commerce
Priority date: 2020-01-21
Filing date: 2020-01-21
Publication date: 2020-09-25
Anticipated expiration: 2030-01-21

Abstract

The utility model discloses a solar energy absorbs and draws compound transcritical CO of penetrating₂A refrigeration system. The utility model consists of transcritical CO₂The refrigeration cycle and the solar energy absorption injection double-subcooler mechanical subcooling cycle are formed, the solar energy absorption injection double-subcooler mechanical subcooling cycle realizes two different evaporation pressure step subcooling through two times of throttling decompression, and therefore the transcritical CO is subjected to₂Refrigeration cycle CO₂CO at the outlet of the gas cooler₂The fluid is continuously supercooled twice in a stepped way, so that better temperature matching is formed in the heat exchange process, the heat transfer temperature difference is reduced, and the CO is obviously reduced₂Irreversible heat exchange loss in the supercooling process, reduced outlet temperature of the gas cooler, and reduced CO₂The throttling loss can be reduced, the compression ratio of the compressor can be reduced, the isentropic efficiency of the compressor can be improved, and the integral COP of the system can be improved. The utility model discloses but wide application needs refrigerated occasion such as freezing cold-stored, low temperature storage.

Description

Solar energy absorption injection composite trans-critical CO2Refrigeration system

Technical Field

The utility model relates to an absorption refrigeration, heat pump technical field especially relate to a solar energy absorbs and draws compound transcritical CO of penetrating₂A refrigeration system.

Background

With the increasing problem of global warming and ozone layer destruction, the refrigeration air-conditioning industry needs to find environment-friendly refrigerants to replace working media such as HFCs, HCFCs and the like which have the effect of destroying the ozone layer and cause the greenhouse effect. The substitution of refrigerant and the environmental protection problem naturally become the focus of attention in the refrigeration air-conditioning industry. Wherein, natural working medium CO₂The refrigerant is an environment-friendly natural working medium which is non-toxic, non-combustible, rich in source and large in unit volume refrigerating capacity, and has attracted wide attention due to the fact that ODP (optical density distribution) is 0 and GWP is extremely low. Due to CO₂The lower critical temperature (31.1 ℃) and the higher critical pressure (7.38MPa) cause large throttle irreversible loss and lower refrigeration efficiency.

Solar energy is used as a renewable clean energy source, solar power generation and a solar water heater are mainly utilized, and solar refrigeration is an important component for solar energy utilization. Solar energy has the advantages of cleanness, environmental protection, long time, universality, better economy and the like, and the development prospect of the solar energy is seen by all countries in the world at present when the energy is increasingly in shortage and the energy is saved and the environment is protected.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects existing in the prior art and provide a solar energy absorption and ejection composite transcritical CO₂A refrigeration system.

The utility model relates to a solar energy absorbs and draws compound transcritical CO of penetrating₂Refrigeration system from transcritical CO₂Refrigeration cycle and solar energy absorption injection double subcooler mechanical subcooling cycle;

(1) transcritical CO₂The refrigeration cycle is made of CO₂Evaporator, CO₂Compressor, CO₂The gas cooler, the primary subcooler, the secondary subcooler and the throttle valve. CO2₂Low temperature and low pressure CO at evaporator outlet₂Fluid is CO₂The compressor sucks in CO compressed to high temperature and high pressure₂Fluid then into CO₂The gas cooler exchanges heat with the heat exchange fluid and then sequentially flows through the primary subcooler CO₂Side and secondary subcooler CO₂The heat is continuously released twice through the evaporation process of the common working medium, and then flows through a throttle valve to be throttled and decompressed in CO₂The evaporator carries out evaporation and heat absorption to complete transcritical CO₂And (4) a refrigeration cycle.

(2) The mechanical supercooling cycle of the solar absorption injection double subcooler comprises a solar vacuum heat collector, a water pump, a water tank, a generator, an injector, a condenser, a throttle valve, a primary subcooler, a secondary subcooler, an absorber, a solution pump and a heat regenerator. The solar vacuum heat collector heats circulating water, and hot water in the water tank circularly heats working medium pairs in the generator to separate refrigerant from the absorbent. The working medium pair in the absorber flows through the low-temperature side of the heat regenerator through the solution pump to be heated, then flows into the generator to be continuously heated to high temperature and high pressure by the solar heat collecting device, the refrigerant in the generator is separated from the absorbent, and the high-temperature absorbent flows through the high temperature of the heat regeneratorThe medium-low temperature refrigerant flowing into the two main flow inlets of the ejector after side and low-temperature side heat exchange is ejected from the common working medium side of the secondary subcooler and flows into the absorber in a mixing chamber for absorption under reduced pressure, and the cooling water carries away heat released in the absorption process through heat exchange of the absorber; the high-temperature refrigerant flows into a main flow inlet of the ejector to entrain the medium-temperature refrigerant from the common working medium side of the primary subcooler, the medium-temperature refrigerant is decompressed and flows into the condenser in the mixing chamber to exchange heat with the heat exchange fluid for cooling, then the medium-temperature refrigerant flows through the throttle valve to be throttled and decompressed and is divided into two paths, one path of low-temperature refrigerant flows into the common working medium side of the primary subcooler to evaporate and absorb heat to₂Then the medium temperature refrigerant is sucked into a primary and secondary inflow port of the ejector; the other path of low-temperature refrigerant flows through the throttle valve again, throttles and reduces the pressure, flows into the common working medium side of the secondary subcooler, evaporates and absorbs heat, and reduces CO again₂Temperature, realization of CO₂And (4) performing step supercooling, and then sucking the medium-low temperature refrigerant into a secondary inflow port of the ejector. The above steps are repeated to complete the mechanical supercooling cycle of the solar absorption injection double subcoolers.

Compared with the prior art, the utility model has the advantages and positive effect be:

(1) conventional mechanical supercooling of CO₂The optimum supercooling degree of the circulation is overlarge, and the supercooling process CO₂The temperature of the refrigerant is not matched with that of the conventional refrigerant, and the irreversible loss of heat exchange is large. The utility model discloses a twice throttle can realize two different evaporating pressures, establishes ties through two subcoolers and realizes the evaporation process of two different temperature positions, the CO of gas cooler export₂Two successive cascade cooling, each supercooling process CO₂The temperature drop of the refrigerant is not high, the refrigerant is well matched with the temperature of the conventional refrigerant in the evaporation process, the heat transfer temperature difference is reduced, the irreversible loss of heat exchange is reduced, and CO is reduced₂The outlet temperature of the gas cooler obtains larger super-cooling degree. With simultaneous reduction of CO entering the throttle valve₂The temperature reduces irreversible throttling loss and improves the overall energy efficiency of the system;

(2) compared with the conventional CO₂Compression process, solar absorption injection composite transcritical CO₂Refrigeration cycle reduces CO₂To reduce compressor discharge pressure, CO₂The pressure ratio of the compressor is reduced, the isentropic efficiency is improved, and the service life of the compressor is prolonged;

(3) transcritical CO₂The circulating refrigerant is natural working medium CO₂. ODP is 0, GWP is 1, and the catalyst can not be decomposed at high temperature, is safe and nontoxic and is environment-friendly. The working medium which can be adopted by the mechanical supercooling cycle of the solar absorption injection double subcoolers is NH₃-H₂O or H₂O-LiBr, the GWP values of which are all 0. The whole environmental protection performance of the system is good.

(4) The utility model discloses a set up ejector one, can reduce absorption refrigeration cycle's condensing pressure, reduce choke valve 8's throttle loss.

(5) The second ejector replaces a throttle valve of a conventional absorption refrigeration system, so that pressure reduction is realized, saturated steam of the second-stage subcooler can be ejected, the pressure of the absorber is improved, the pressure difference between the absorber and the generator is reduced, and the power consumption of the solution pump is reduced. The promotion of absorber pressure has increased the evaporating temperature of absorber, and then has increased the heat transfer difference in temperature between cooling water and the absorber, and the heat transfer effect is showing to reduced the volume and the heat transfer area of absorber, had better economic nature.

(6) The utility model converts solar energy into cold energy through the absorption refrigeration system and supplies CO with the cold energy₂The refrigeration system performs supercooling, realizes cascade utilization of energy, and promotes CO through renewable energy sources₂Energy efficiency of the refrigeration system.

Drawings

FIG. 1 shows a solar absorption injection composite trans-critical CO₂A schematic diagram of a refrigeration system.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

The utility model consists of transcritical CO₂The system comprises a refrigeration cycle, a solar energy absorption injection double-subcooler mechanical supercooling cycle, a heat exchange fluid heating process and a heat exchange fluid refrigeration process, and a schematic diagram is shown in figure 1. The specific implementation mode is as follows:

the first step is as follows: CO2₂Low temperature and low pressure CO at the outlet of the evaporator 13₂Fluid is CO₂The compressor 14 sucks in CO compressed to a high temperature and a high pressure₂Fluid then into CO₂The gas cooler 15 exchanges heat with a heat exchange fluid and then sequentially flows through the primary subcooler 9CO₂Side and secondary subcooler 11CO₂The heat release is continuously carried out twice through the evaporation process of the refrigerant, and then the heat release flows into CO after flowing through a throttle valve III 12 for throttling and pressure reduction₂The evaporator 13 carries out evaporation and heat absorption to complete transcritical CO₂And (4) a refrigeration cycle.

The second step is that: fluid in the solar thermal collector 1 and fluid in the water tank 3 circulate through the first pump 2, fluid in the water tank 3 circularly heats fluid in the generator 5 through the second pump 4, working medium pairs in the generator 5 are circularly heated by hot water in the water tank 3, and the working medium pairs are separated into high-temperature high-pressure refrigerant and absorbent. The low-temperature and low-pressure working medium pair in the absorber 16 flows through the low-temperature side of the heat regenerator 19 through the solution pump 17 to be heated, then flows into the generator 5 to be continuously heated to high temperature and high pressure by the solar heat collection device, the high-temperature and high-pressure refrigerant in the generator 5 is separated from the absorbent, the high-temperature absorbent flows through the high-temperature side of the heat regenerator 19 to exchange heat with the low-temperature side, then flows into the main flow inlet of the ejector 18 to entrain the medium-low-temperature refrigerant from the common working medium side of the secondary subcooler 11, and flows into the absorber in a mixing chamber to be decompressed for absorption; the high-temperature refrigerant flows into a main flow inlet of the first ejector 6 to entrain the medium-temperature refrigerant from the common working medium side of the first-stage subcooler 9, the medium-temperature refrigerant is decompressed and flows into the condenser 7 in the mixing chamber to exchange heat with the heat exchange fluid for cooling, then flows through the throttle valve 8 to be throttled and decompressed and divided into two paths, one path of low-temperature refrigerant flows into the common working medium side of the first-stage subcooler 9 to evaporate and₂ gas cooler 15 outlet CO₂Then the medium temperature refrigerant is sucked into a first 6 secondary inflow ports of the ejector in a winding mode; the other path of low-temperature refrigerant flows through the throttle valve II 10 again, is throttled and reduced in pressure, flows into the secondary subcooler 11 to evaporate and absorb heat at the common working medium side, and reduces CO again₂Temperature, realization of CO₂And (4) performing step supercooling, and then sucking the medium-low temperature refrigerant into a secondary inflow port of the second ejector 18. The above steps are repeated to complete the mechanical supercooling cycle of the solar absorption injection double subcoolers.

Claims

1. Solar energy absorption injection composite trans-critical CO₂Refrigeration system characterized by transcritical CO₂Refrigeration cycle and solar energy absorption injection double subcooler mechanical subcooling cycle;

the trans-critical CO₂The refrigeration cycle comprising CO₂Evaporator (13), CO₂Compressor (14), CO₂A gas cooler (15) and a third throttle valve (12); the solar energy absorption injection double-subcooler mechanical subcooling cycle comprises a solar heat collector (1), a water pump I (2), a water tank (3), a water pump II (4), a generator (5), an injector I (6), a condenser (7), a throttle valve I (8), a primary subcooler (9), a throttle valve II (10), a secondary subcooler (11), an absorber (16), a solution pump (17), an injector II (18) and a heat regenerator (19);

the CO is₂Outlet of evaporator (13) and CO₂The inlet of the compressor (14) is connected, and the CO is₂Compressor (14) outlet and CO₂The inlet of the gas cooler (15) is connected, and the CO is₂The outlet of the gas cooler (15) and the CO of the primary subcooler (9)₂The side inlet is connected with the primary subcooler (9) CO₂Side outlet and secondary subcooler (11) CO₂The side inlet is connected with the secondary subcooler (11) CO₂The side outlet is connected with the inlet of a third throttle valve (12), and the outlet of the third throttle valve (12) is connected with CO₂The inlet of the evaporator (13) is connected;

the fluid in the solar heat collector (1) and the fluid in the water tank (3) circulate through the first pump (2), and the fluid in the water tank (3) circularly heats the fluid in the generator (5) through the second pump (4); an outlet of the absorber (16) is connected with a low-temperature measuring inlet of a heat regenerator (19) through a solution pump (17), a low-temperature measuring outlet of the heat regenerator (19) is connected with a refrigerating working medium pair inlet of the generator (5), fluid in the generator (5) is divided into two paths, one path is an absorbent outlet connected with a high-temperature measuring inlet of the heat regenerator (19), a high-temperature measuring outlet of the heat regenerator (19) is connected with a main flow inlet of a second ejector (18), and an outlet of the second ejector (18) is connected with an inlet of the absorber (16); the other path is that a refrigerant outlet is connected with a main flow inlet of a first ejector (6), an outlet of the first ejector (6) is connected with an inlet of a condenser (7), an outlet of the condenser (7) is connected with an inlet of a first throttle valve (8), an outlet of the first throttle valve (8) is divided into two paths, one path is connected with a side inlet of a common working medium of a first-stage subcooler (9), and a side outlet of the common working medium of the first-stage subcooler (9) is connected with a secondary flow inlet of the first ejector (6); the other path is connected with an inlet of a second throttle valve (10), an outlet of the second throttle valve (10) is connected with a side inlet of a common working medium of a second-stage subcooler (11), and a side outlet of the common working medium of the second-stage subcooler (11) is connected with a secondary inflow port of a second ejector (18).

2. The solar absorption ejector composite trans-critical CO of claim 1₂The refrigerating system is characterized in that the working medium adopted by the mechanical supercooling circulation of the solar absorption injection double subcoolers is NH₃-H₂O or LiBr-H₂O。