CN211575584U

CN211575584U - Absorption compression injection composite cascade supercooling transcritical CO2 cold and heat combined supply system

Info

Publication number: CN211575584U
Application number: CN202020137844.1U
Authority: CN
Inventors: 代宝民; 窦萬斌; 钱家宝; 曹钰; 杨海宁; 郝云樱; 冯一宁
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 provides an absorption compression draws compound step supercooling transcritical CO of penetrating₂A combined cooling and heating system. The utility model consists of transcritical CO₂The system consists of a refrigeration cycle, an absorption compression injection composite step supercooling cycle and a hot end heat supply cycle, wherein the absorption compression injection composite step supercooling cycle is subjected to step throttling depressurization, so that continuous two-time step supercooling transcritical CO is realized₂Refrigeration cycle CO₂CO at the outlet of the gas cooler₂The fluid can form better temperature matching in the heat exchange process, the heat transfer temperature difference is reduced, and CO is generated₂The irreversible loss of heat exchange in the supercooling process is obviously reduced, and CO at the outlet of the gas cooler₂The temperature of the fluid is reduced, thereby reducing CO₂The throttling loss is reduced, the compression ratio of the compressor is reduced, the isentropic efficiency is improved, and the COP of the system is further improved. The utility model discloses but cold and hot combined supply system wide application in refrigeration, system high temperature hot water, multiple occasions that need refrigeration or heat such as heating.

Description

Absorption compression injection composite step supercooling transcritical CO2Cold and hot combined supply system

Technical Field

The utility model relates to a refrigeration heats, absorption refrigeration, heat pump technical field, especially relates to an absorption compression draws compound step supercooling transcritical CO₂A combined cooling and heating system.

Background

Nowadays, energy is increasingly in short supply and environmental problems are more prominent, and a feasible energy-saving and environment-friendly mode is sought in the whole society. Meanwhile, new technologies and new products with excellent performance, low price and stable operation are continuously emerging. In the aspect of energy consumption, heating and refrigerating air-conditioning buildings occupy a large area, are large users of electricity in the buildings, and need to explore a novel energy-saving refrigerating heat pump technology. For civil and commercial applications, the demand for refrigeration and heating is increasing dramatically. At present, the requirements for low temperature and high temperature are mainly met by respectively working two or a plurality of devices, so that energy waste and environmental damage are caused to a great extent. Meanwhile, most of the filled refrigerants of the equipment are HFCs high GWP working media.

CO₂Compared with the traditional technology, the refrigeration technology is more efficient, energy-saving and environment-friendly. Carbon dioxide is known as a substitute with the most development potential of CFCs, HCFCs and HFCs by virtue of its excellent characteristics. Therefore, the green carbon dioxide refrigeration technologyThe method has wide development prospect. However, due to CO₂The critical temperature is lower (31.1 ℃), the critical pressure is higher (7.38MPa), the throttle irreversible loss is large, the refrigeration efficiency is lower, and the transcritical CO is treated₂CO at the outlet of the gas cooler of the refrigeration cycle₂Cooling can reduce throttling loss, increase circulating cold capacity and reduce CO₂The high pressure of the circulation operation and the exhaust pressure of the compressor prolong the service life of the compressor and improve the COP of the circulation.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects existing in the prior art and provide an absorption compression injection composite step supercooling transcritical CO₂A combined cooling and heating system.

The utility model relates to an absorption compression draws and penetrates compound step supercooling transcritical CO₂The combined cooling and heating system is characterized by transcritical CO₂Refrigeration cycle, absorption compression injection composite step supercooling cycle and hot end heat supply cycle;

(1) transcritical CO₂The refrigeration cycle is made of CO₂Compressor, CO₂Gas cooler, throttle valve five and CO₂An evaporator. 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, flows through a throttle valve, is throttled by five, is reduced in pressure and then is subjected to CO₂The evaporator carries out evaporation and heat absorption to complete transcritical CO₂And (4) a refrigeration cycle.

(2) The absorption compression injection composite cascade supercooling cycle consists of a three-way valve I, an absorber, a solution pump, a throttle valve I, a regenerator, a heat consumer, a three-way valve II, a generator, an injector, a condenser, a throttle valve II, a gas-liquid separator, a throttle valve III, a primary subcooler, a throttle valve IV, a secondary subcooler and a compressor. The working medium pair in the absorber flows through the low-temperature side of the heat regenerator through the solution pump to be heated and then flows into the heat regeneratorThe generator is continuously heated to high temperature and high pressure, a refrigerant in the generator is separated from an absorbent, the high-temperature absorbent flows through a throttle valve after heat exchange between the high-temperature side and the low-temperature side of the heat regenerator, flows through the throttle valve for throttling and pressure reduction, flows into the absorber for absorption, and cooling water flows through the absorber for heat exchange to take away heat released in the absorption process; the high-temperature refrigerant flows into a main flow inlet of the ejector to eject medium-temperature refrigerant gas from the gas-liquid separator, the medium-temperature refrigerant gas is decompressed in the mixing chamber and flows into the condenser to exchange heat with the heat exchange fluid for cooling, and then flows into the gas-liquid separator after throttling and decompressing through the throttle valve; the medium temperature refrigerant at the liquid outlet of the gas-liquid separator flows through a throttle valve for three-throttling and pressure reduction and then is divided into two paths, one path of low temperature refrigerant flows into a primary subcooler for common working medium side evaporation and heat absorption to reduce CO₂Gas cooler outlet CO₂(ii) temperature; 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, compressing the refrigerant gas at the outlet of the common working medium side of the secondary subcooler to high temperature and high pressure by a compressor, and converging the refrigerant gas with the refrigerant at the outlet of the common working medium side of the primary subcooler to flow into an absorber. Repeating the steps to complete the absorption compression injection composite step supercooling cycle.

(3) Hot end heat supply circulation is by absorber, CO₂The gas cooler, the condenser, the three-way valve and the heat consumer. The low-temperature circulating fluid at the outlet of the heat user flows through the absorber and the CO respectively₂The cooling fluid side of the gas cooler is heated, and the medium temperature fluid at the outlet of the cooling fluid side of the absorber flows through the cooling fluid side of the condenser to be heated to high temperature and CO again₂The gas cooler cooling fluid side outlet high temperature fluid merges and then flows into the hot user. Repeating the steps to complete the hot end heat supply circulation.

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

(1) for solving the problem of conventional mechanical supercooling 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, so that the irreversible loss of heat exchange is large. The utility model discloses a step throttle realizes two different evaporating pressures, establishes ties through two subcoolers and realizesTwo evaporation processes with different temperature levels, two successive times for cooling CO at the outlet of the gas cooler₂Fluid, each supercooling process CO₂The temperature drop of the refrigerant is not high, good temperature matching with the evaporation process of the conventional refrigerant is realized, the heat transfer temperature difference is reduced, the irreversible loss of heat exchange is reduced, and CO is₂The outlet temperature of the gas cooler is reduced to obtain larger supercooling degree. With simultaneous reduction of CO entering the throttle valve₂The temperature reduces irreversible throttling loss, and the overall energy efficiency of the system is improved;

(2) compared with the conventional CO₂Compression process, absorption compression ejection composite step supercooling transcritical CO₂Refrigeration cycle reduces CO₂The operation high pressure of the compressor is reduced, the pressure ratio is reduced, the isentropic efficiency is improved, and the service life of the compressor is prolonged;

(3) absorption compression injection composite step supercooling transcritical CO₂The combined cooling and heating system can meet the requirement of simultaneous cooling and heating, the cold end can be used for cooling rooms, storing food and the like, and the hot end can be used for supplying household hot water and the like. Compared with the traditional equipment, the system can realize the functions of refrigerating and heating simultaneously, is compact, reduces the occupied area of the equipment and has high overall energy efficiency.

(4) CO is realized by inputting a high-grade heat source, absorbing, compressing, injecting and compounding cascade supercooling circulation₂The recycling subcools and by reducing the energy grade, more low grade heat is obtained for heating. Condensation heat and CO of absorption compression injection composite cascade supercooling cycle are utilized to the maximum degree₂The circulating gas cools to release heat. And the efficient cascade utilization of energy is realized.

(5) 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.

(6) By arranging the ejector, the condensation pressure of the absorption refrigeration cycle can be reduced, and the throttling loss of the throttling valve II is reduced.

(7) The device can exchange heat with different heat exchange fluids such as air, water and the like, and can be applied to multiple occasions such as heating and cooling combined supply, medium-high temperature hot water production and the like. Heating ofThe tail end of the air conditioner can be provided with a fan coil, a ground coil, a radiator and other devices, and the condenser and the gas cooler directly provide heat for the air conditioner for room heating; CO2₂The evaporator exchanges heat with air to realize the refrigeration function.

Drawings

FIG. 1 shows absorption compression injection composite cascade supercooling transcritical CO₂A combined cooling and heating system.

Detailed Description

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

The utility model discloses draw compound step supercooling circulation, transcritical CO by absorption compression₂The schematic diagram of the refrigeration cycle and the hot-end heating cycle 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 21₂Fluid is CO₂The compressor 1 sucks in CO compressed to a high temperature and a high pressure₂Fluid then into CO₂The gas cooler 2 exchanges heat with a heat exchange fluid and then sequentially flows through a primary subcooler 16CO₂Side and secondary subcooler 18CO₂The heat is continuously released twice through the evaporation process of the refrigerant, and then flows through a five throttle valve 20, is throttled and depressurized and flows into CO₂The evaporator 21 carries out evaporation and heat absorption to complete transcritical CO₂And (4) a refrigeration cycle.

The second step is that: working medium pairs in the absorber 4 flow through the low-temperature side of the heat regenerator 7 through the solution pump 5 to be heated, then flow into the generator 10 to be continuously heated to high temperature and high pressure, a refrigerant in the generator 10 is separated from an absorbent, the high-temperature absorbent flows through the high-temperature side of the heat regenerator 7 to exchange heat with the low-temperature side, then flows through the throttle valve I6 to be throttled and decompressed, then flows into the absorber 4 to be absorbed, and cooling water flows through the absorber 4 to exchange heat to take away heat released in the absorption process; the high-temperature refrigerant flows into a main flow inlet of the ejector 11 to eject medium-temperature refrigerant gas from the gas-liquid separator 14, the medium-temperature refrigerant gas is decompressed in the mixing chamber and flows into the condenser 12 to exchange heat with the heat exchange fluid for cooling, and then flows into the gas-liquid separator 14 after throttling and decompressing through the throttling valve II 13; the medium temperature refrigerant at the liquid outlet of the gas-liquid separator 14 passes through a throttle valve III 15, is throttled and decompressed and then is divided into two paths,one path of low-temperature refrigerant flows into the primary subcooler 16 to evaporate and absorb heat at the common working medium side to reduce CO₂Gas cooler 2 outlet CO₂(ii) temperature; the other path of low-temperature refrigerant flows through the throttle valve four 17 again, is throttled and reduced in pressure, flows into the secondary subcooler 18 to evaporate and absorb heat at the common working medium side, and reduces CO again₂Temperature, realization of CO₂After the refrigerant gas at the outlet of the common working medium side of the secondary subcooler 18 is compressed to high temperature and high pressure by the compressor 19, the refrigerant gas is converged with the refrigerant at the outlet of the common working medium side of the primary subcooler 16 and flows into the absorber 4. Repeating the steps to complete the absorption compression injection composite step supercooling cycle.

The third step: the low-temperature circulating fluid at the outlet of the heat user flows through the absorber and the CO respectively₂The gas cooler cooling fluid side is heated, and then the intermediate temperature fluid at the absorber cooling fluid side outlet is heated again to high temperature and CO by flowing through the condenser cooling fluid side₂The gas cooler cooling fluid side outlet high temperature fluid merges and then flows into the hot user. Repeating the steps to complete the hot end heat supply circulation.

Claims

1. Absorption compression injection composite cascade supercooling transcritical CO₂The combined cooling and heating system is characterized by transcritical CO₂Refrigeration cycle, absorption compression injection composite step supercooling cycle and hot end heat supply cycle;

the trans-critical CO₂The refrigeration cycle comprising CO₂Compressor (1), CO₂Gas cooler (2), throttle valve five (20), CO₂An evaporator (21);

the absorption compression injection composite step supercooling cycle comprises a three-way valve I (3), an absorber (4), a solution pump (5), a throttle valve I (6), a heat regenerator (7), a heat consumer (8), a three-way valve II (9), a generator (10), an injector (11), a condenser (12), a throttle valve II (13), a gas-liquid separator (14), a throttle valve III (15), a primary subcooler (16), a throttle valve IV (17), a secondary subcooler (18) and a compressor (19);

the CO is₂Outlet of evaporator (21) and CO₂The inlet of the compressor (1) is connected, and the CO is₂Compressor (1) outlet and CO₂Gas coolingThe inlet of the device (2) is connected with the CO₂The outlet of the gas cooler (2) and the primary subcooler (16) CO₂The side inlet is connected with the primary subcooler (16) CO₂Side outlet and secondary subcooler (18) CO₂Side inlet connected, the secondary subcooler (18) CO₂The side outlet is connected with the inlet of a five-throttle valve (20), and the outlet of the five-throttle valve (20) is connected with CO₂The inlet of the evaporator (21) is connected;

an outlet of the absorber (4) is connected with a low-temperature inlet of a heat regenerator (7) through a solution pump (5), a low-temperature outlet of the heat regenerator (7) is connected with a refrigerating working medium pair inlet of a generator (10), fluid in the generator (10) is divided into two paths, one path is an absorbent outlet connected with a high-temperature inlet of the heat regenerator (7), a high-temperature outlet of the heat regenerator (7) is connected with an inlet of a throttle valve I (6), and an outlet of the throttle valve I (6) is connected with an inlet of the absorber (4); the other path is that a refrigerant outlet is connected with a main flow inlet of an ejector (11), an outlet of the ejector (11) is connected with an inlet of a condenser (12), an outlet of the condenser (12) is connected with an inlet of a second throttling valve (13), an outlet of the second throttling valve (13) is connected with an inlet of a gas-liquid separator (14), and a gas outlet of the gas-liquid separator (14) is connected with a secondary flow inlet of the ejector (11); a liquid outlet of the gas-liquid separator (14) is connected with an inlet of a throttle valve III (15), an outlet of the throttle valve III (15) is divided into two paths, and one path of the outlet is connected with a side inlet of a common working medium of a primary subcooler (16); the other path of the refrigerant is connected with an inlet of a throttle valve four (17), an outlet of the throttle valve four (17) is connected with a side inlet of a common working medium of a secondary subcooler (18), a side outlet of the common working medium of the secondary subcooler (18) is connected with an inlet of a compressor (19), and an outlet of the compressor (19) is connected with a side outlet of the common working medium of a primary subcooler (16) and then connected with an inlet of an absorber (4);

the outlet of the heat user (8) is connected with the inlet of a first three-way valve (3), the outlet of the first three-way valve (3) is connected with the cooling fluid side inlet of the absorber (4), the cooling fluid side outlet of the absorber (4) is connected with the cooling fluid side inlet of the condenser (12), and the cooling fluid side outlet of the condenser (12) is connected with the inlet of a second three-way valve (9); the other outlet of the first three-way valve (3) and CO₂The gas cooler (2) is connected with the cooling fluid side inlet, and the CO is₂Cooling by gas cooler (2)And the outlet of the cooling fluid side is connected with the inlet of a second three-way valve (9), and the outlet of the second three-way valve (9) is connected with the inlet of a heat user (8).

2. The absorption compression injection composite step subcooling transcritical CO according to claim 1₂The combined cooling and heating system is characterized in that NH is recycled by absorption, compression, injection and composite cascade supercooling₃-H₂O or LiBr-H₂And O is used as a working medium.