阅读说明：本技术 一种非共沸工质增压机械过冷co2跨临界制冷系统 (A kind of non-azeotropic working medium supercharging mechanical supercooling CO2Transcritical cooling system ) 是由 代宝民 孙悦桐 杨茜茹 马牧宇 王璐 何小敏 杨和澄 郭梦迪 于 2019-09-05 设计创作，主要内容包括：本发明公开了一种非共沸工质增压机械过冷CO_2跨临界制冷系统。本发明的CO_2跨临界制冷循环系统包括气体冷却器、中温级冷却蒸发器、低温级冷却蒸发器、节流阀、蒸发器、压缩机；所述非共沸工质增压机械过冷循环系统包括中温级压缩机、冷凝器、高温级节流阀、储液器、中温级节流阀、旁通阀、低温级节流阀、低温级压缩机。本发明通过非共沸工质增压机械辅助过冷循环,使换热形成更良好的温度匹配,缩小了传热温差、减小了换热过程的不可逆损失,进而减小了冷凝器和蒸发器的传热不可逆损失,使制冷循环的效率得以提高。(The invention discloses a kind of non-azeotropic working medium supercharging mechanicals, and CO is subcooled 2 Transcritical cooling system.CO of the invention 2 Trans-critical cycle cooling cycle system includes gas cooler, medium temperature grade cooling evaporator, low-temperature level cooling evaporator, throttle valve, evaporator, compressor；The non-azeotropic working medium supercharging mechanical supercooling circulatory system includes medium temperature grade compressor, condenser, high-temperature level throttle valve, liquid storage device, medium temperature grade throttle valve, by-passing valve, low-temperature level throttle valve, low-temperature level compressor.The present invention assisted SAPMAC method by non-azeotropic working medium supercharging mechanical, heat exchange is set to form more good Temperature Matching, it reduces heat transfer temperature difference, reduce the irreversible loss of heat transfer process, and then reduce the heat transfer irreversible loss of condenser and evaporator, be improved the efficiency of refrigeration cycle.)

1. CO is subcooled in a kind of non-azeotropic working medium supercharging mechanical₂Trans critical cycle refrigeration system, which is characterized in that by non-azeotropic working medium The circulatory system and CO is subcooled in supercharging mechanical₂Trans-critical cycle cooling cycle system coupling composition；

The CO₂Trans-critical cycle cooling cycle system include gas cooler, medium temperature grade cooling evaporator, low-temperature level cooling evaporator, Throttle valve, evaporator, compressor；The compressor outlet is connected with gas cooler entrance, gas cooler outlet and medium temperature Grade cooling evaporator entrance is connected, and the outlet of medium temperature grade cooling evaporator is connected with low-temperature level cooling evaporator entrance, and low-temperature level is cold But evaporator outlet is connect with expansion valve inlet, and expansion valve outlet is connected with evaporator inlet, evaporator inlet and compressor phase Even；

The non-azeotropic working medium supercharging mechanical supercooling circulatory system includes medium temperature grade compressor, condenser, high-temperature level throttle valve, storage Liquid device, medium temperature grade throttle valve, by-passing valve, low-temperature level throttle valve, low-temperature level compressor；The medium temperature stage compressor outlet and condensation Device entrance is connected, and condensator outlet is connected with high-temperature level throttling valve inlet, and high-temperature level throttling valve outlet is connected with liquid storage device entrance, Reservoir outlet is connected with bypass valve inlet, and bypass valve outlet is connected with medium temperature grade suction port of compressor；Liquid storage device and medium temperature grade section It flows valve inlet to be connected, medium temperature grade throttling valve outlet is connected with medium temperature grade cooling evaporator entrance, the outlet of medium temperature grade cooling evaporator It is connected with medium temperature grade suction port of compressor；The liquid storage device and low-temperature level throttling valve inlet are connected, low-temperature level throttling valve outlet with it is low Warm grade cooling evaporator entrance is connected, and the outlet of low-temperature level cooling evaporator is connected with low-temperature level suction port of compressor, low-temperature level compression Machine outlet is connected with medium temperature grade suction port of compressor.

2. CO is subcooled in non-azeotropic working medium supercharging mechanical according to claim 1₂Trans critical cycle refrigeration system, feature exist In the medium temperature cooling evaporator, sub-cooled evaporator and condenser are counter-flow heat exchanger.

3. CO is subcooled in non-azeotropic working medium supercharging mechanical according to claim 1₂Trans critical cycle refrigeration system, feature exist In non-azeotropic working medium supercharging mechanical is subcooled circularly cooling agent and uses natural refrigerant CO₂, CO₂The refrigerant of Trans-critical cycle refrigeration cycle is CO₂/R1234ze、CO₂/ R1234yf, R41/R1234ze, R41/R1234yf, R32/R1234ze, R32/R1234yf or R32/ R600a。

Technical field

The present invention relates to refrigeration technology fields, and CO is subcooled more particularly to a kind of non-azeotropic working medium supercharging mechanical₂Trans-critical cycle Refrigeration system.

Background technique

As global warming, ozone layer such as are destroyed at the getting worse for environmental problems, for air-conditioning and refrigeration industry, most Important research topic is to find new environmentally friendly natural refrigerants, and substitution has destruction to ozone layer and can generate The working medium such as CFCs, HCFCs of greenhouse effects.CO₂As refrigerant, due to its is nontoxic, abundance, with plain oil phase Molten, the advantages that refrigerating effect per unit swept volume is big, more and more attention has been paid to.

But due to CO₂Lower critical-temperature and higher critical pressure, cause refrigerating efficiency lower, especially work as environment When temperature is higher, CO₂Refrigerating capacity sharply decline, and power consumption increase.If to the CO of gas cooler outlet₂Fluid carries out Supercooling, with the increase of degree of supercooling, restriction loss is reduced, and circulation cooling capacity increases, and then can promote circulation COP.It is steamed by auxiliary Vapour pressure contraction SAPMAC method, to CO₂The CO of Trans-critical cycle refrigeration cycle gas cooler outlet₂It carries out cooling method and is known as mechanical mistake It is cold.Mechanical super cooling can not only increase refrigerating capacity, and can reduce the operation high pressure of major cycle, reduce compressor air-discharging pressure Power extends the service life of compressor.

When mechanical super cooling circulation using pure refrigerant as refrigerant when, evaporative phase-change process temperature remains unchanged, but across facing Boundary CO₂Fluid cooling procedure is temperature-fall period, and the two heat transfer process temperature mismatches, and causes heat transfer process irreversible loss big. And, evaporating temperature lower application higher for environment temperature, such as freezer, CO₂Degree of supercooling is up to 20 DEG C or more.It is mechanical Supercooling refrigeration cycle condensation side exchanges heat with air, evaporation side and CO₂Fluid exchanges heat, and the temperature rise of air side does not surpass generally Cross 8 DEG C, and CO₂Temperature drop be 20 DEG C or so, and non-azeotropic working medium evaporation and the slip temperature of condensation process are not much different, and such as adopt It is subcooled with conventional non-azeotropic working medium refrigeration cycle single-stage, air side and CO cannot be met simultaneously₂The Temperature Matching of fluid side, thus It can cause biggish irreversible loss again.

Therefore, the condensation and evaporation process point for improving with while realizing mechanical super cooling circulation need to be recycled to mechanical super cooling Not with air and CO₂Fluid forms good Temperature Matching, and then reduces the whole irreversible loss of circulation to the greatest extent, from And lifting system entirety efficiency.

Summary of the invention

Present invention aims at, overcome above-mentioned the deficiencies in the prior art, and a kind of non-azeotropic working medium pressurization is provided Mechanical super cooling CO₂Trans-critical cycle cooling cycle system,

The present invention is by mechanical super cooling cooling cycle system and CO₂Trans-critical cycle cooling cycle system forms, wherein mechanical super cooling Cooling cycle system is that both vapor compression is pressurized refrigeration cycle, and refrigerant is low GWP mixed non-azeotropic refrigerant CO₂/R1234ze、 CO₂/ R1234yf, R41/R1234ze, R41/R1234yf, R32/R1234ze, R32/R1234yf or R32/R600a.

The technical solution used in the present invention is:

A kind of non-azeotropic working medium mechanical-assisted supercooling CO₂Trans-critical cycle cooling cycle system, including non-azeotropic mixed working medium machine Cooling cycle system and CO is subcooled in tool₂Trans-critical cycle cooling cycle system；

The CO₂Trans-critical cycle cooling cycle system includes gas cooler, medium temperature grade cooling evaporator, the cooling steaming of low-temperature level Send out device, throttle valve, evaporator, compressor；The compressor outlet is connected with gas cooler entrance, gas cooler outlet with Medium temperature grade cooling evaporator entrance is connected, and the outlet of medium temperature grade cooling evaporator is connected with low-temperature level cooling evaporator entrance, low temperature The outlet of grade cooling evaporator is connect with expansion valve inlet, and expansion valve outlet is connected with evaporator inlet, evaporator inlet and compression Machine is connected；

The non-azeotropic working medium supercharging mechanical supercooling circulatory system includes medium temperature grade compressor, condenser, high-temperature level throttling Valve, liquid storage device, medium temperature grade throttle valve, by-passing valve, low-temperature level throttle valve, low-temperature level compressor；The medium temperature stage compressor outlet It is connected with condenser inlet, condensator outlet is connected with high-temperature level throttling valve inlet, and high-temperature level throttling valve outlet enters with liquid storage device Mouth is connected, and reservoir outlet is connected with bypass valve inlet, and bypass valve outlet is connected with medium temperature grade suction port of compressor；Liquid storage device is in Warm grade throttling valve inlet is connected, and medium temperature grade throttling valve outlet is connected with medium temperature grade cooling evaporator entrance, the cooling evaporation of medium temperature grade Device outlet is connected with medium temperature grade suction port of compressor；The liquid storage device is connected with low-temperature level throttling valve inlet, and low-temperature level throttle valve goes out Mouth is connected with low-temperature level cooling evaporator entrance, and the outlet of low-temperature level cooling evaporator is connected with low-temperature level suction port of compressor, low temperature Stage compressor outlet is connected with medium temperature grade suction port of compressor.

The medium temperature cooling evaporator, sub-cooled evaporator and condenser are counter-flow heat exchanger.

Non-azeotropic working medium supercharging mechanical is subcooled circularly cooling agent and uses natural refrigerant CO₂, CO₂The system of Trans-critical cycle refrigeration cycle Cryogen is CO₂/R1234ze、CO₂/R1234yf、R41/R1234ze、R41/R1234yf、R32/R1234ze、R32/R1234yf Or R32/R600a.

The low-temperature level compressor of non-azeotropic mixed working medium mechanical-assisted supercooling refrigeration system goes out low-temperature level cooling evaporator Mouthful mixed non-azeotropic refrigerant be compressed to medium temperature grade evaporating pressure, with medium temperature cooling evaporator outlet medium temperature and medium pressure gas with And the gas mixing in the gas-liquid separation through by-passing valve, enter medium temperature grade compressor later.Gas is compressed into high temperature and pressure gas Body, enters condenser later, and the liquid of condensator outlet is first that gas-liquid two-phase fluid enters liquid storage through the throttling of medium temperature grade throttle valve In device, realize gas-liquid separation in liquid storage device, liquid pass through in mild low-temperature level throttle valve throttled respectively to medium temperature and low-temperature level Cooling evaporator, and evaporated in the cooling evaporator respectively, CO₂Fluid is real followed by medium temperature and low-temperature level evaporator Now to CO₂Fluid carries out once cooling and secondary cooling, so that CO₂Obtain higher degree of supercooling, the non-azeotrope work after heat absorption evaporation Matter all becomes saturated air, respectively enters low temperature and medium temperature grade compressor is compressed, and completes mechanical super cooling circulation.

CO₂The working medium filled in cooling cycle system is CO₂, compressor by refrigerant compression at high temperature and high pressure gas, first Exchange heat into gas cooler and air, later followed by medium temperature supercooling evaporator and low temperature supercooling evaporator and with it is non- Azeotropic working medium is carried out continuously to exchange heat twice, after in throttle valve expand decompression, CO₂Decompression becomes the biphase gas and liquid flow of low-temp low-pressure Then body flows into evaporator and absorbs heat, sucks suction port of compressor after becoming low temperature low pressure gas, complete circulation.

Compared with prior art, the advantages and positive effects of the present invention are:

(1)CO₂The refrigerant of refrigeration system is natural refrigerant CO₂。CO₂GWP be 1, ODP 0, it is safe and non-toxic it is non-combustible, It is cheap easily to obtain, do not decompose generation pernicious gas, mechanical super cooling cycle fluid CO under the high temperature conditions yet₂/R1234ze、CO₂/ The GWP of R1234yf, R41/R1234ze, R41/R1234yf, R32/R1234ze, R32/R1234yf or R32/R600a are lower, Refrigerant used in system is environmental-friendly refrigerant.

(2) mechanical super cooling circulation uses mixed non-azeotropic refrigerant, and temperature glide is suitable with the inlet and outlet temperature difference of air, Refrigerant is alternating temperature process in condenser and evaporator phase transition process, wherein condenser side non-azeotropic refrigerant and air shape At good Temperature Matching.Supercritical CO₂It is cooled down twice in fluid subcooling process, the temperature drop of each subcooling process is not Height forms good Temperature Matching with non-azeotropic refrigerant low temperature and medium temperature evaporation process, and heat exchange irreversible loss greatly reduces. In conclusion the irreversible damage of heat exchange of the condenser and cooling evaporator recycled by lesser mechanical super cooling, obtains higher CO₂The degree of supercooling of gas cooler improves system energy efficiency, increases refrigerating capacity.

(3) by mechanical super cooling system to CO₂The CO of system gas cooler outlet₂It is subcooled, is lowered into expansion valve Preceding CO₂Temperature reduces expansion-loss, and further decreases CO₂Run high pressure.

(4) mechanical-assisted crosses SAPMAC method liquid storage device and plays the role of flash tank, reduces evaporator inlet refrigerant enthalpy Value, improves system performance.

(5) opposite CO2 transcritical cooling system, the small in size of mechanical super cooling circulation, wasted work are few, by configuring small refrigeration Being obviously improved for performance can be realized in system, and at low cost, economic advantages are obvious.

Detailed description of the invention

Fig. 1 is that CO is subcooled in non-azeotropic working medium supercharging mechanical of the present invention₂The CO of Trans-critical cycle cooling cycle system₂Trans-critical cycle refrigeration The Sweet service of circulation；

Fig. 2 is that CO is subcooled in non-azeotropic working medium supercharging mechanical of the present invention₂Refrigeration is subcooled in the auxiliary of Trans-critical cycle cooling cycle system The Sweet service of circulation；

Fig. 3 is that CO is subcooled in non-azeotropic working medium supercharging mechanical of the present invention₂The schematic diagram of Trans-critical cycle cooling cycle system.

Specific embodiment

The present invention will be further described with reference to the accompanying drawing.

The present invention includes the both vapor compression supercharging mechanical supercooling circulatory system and CO as shown in Figure 1₂Trans-critical cycle refrigeration cycle system System, heavy line CO₂Trans critical cycle (1 ' -2 ' -3 ' -4 ' -5 ' -6 ' -1 '), fine line are that the supercooling of both vapor compression supercharging mechanical follows The low-temperature evaporation process (10-12) and high temperature evaporation process (6-7) of ring.Fig. 2 is non-azeotropic working medium supercharging mechanical of the present invention supercooling CO₂The Sweet service of the auxiliary supercooling refrigeration cycle of Trans-critical cycle cooling cycle system, wherein 3 ' -4 ' be CO₂Level-one subcooling process, 6 ' -5 ' be CO₂Second level subcooling process.

Present system is as shown in Figure 3:

Step 1: compressor 1 sucks the saturation CO of the low-temp low-pressure in 6 exit of evaporator₂Gas compresses it into high temperature The gas of high pressure, temperature reduces after being exchanged heat in gas cooler 2 with air, flows separately through medium temperature cooling evaporator later 3 exchange heat with sub-cooled evaporator 4 with mixed non-azeotropic refrigerant, realize CO₂Supercooling enters back into the throttling drop of throttle valve 5 Pressure, becomes gas-liquid two-phase state.Become overheated gas after 6 evaporation endothermic of evaporator again and enter compressor, completes CO₂Trans-critical cycle Circulation.

Step 2: mechanical super cooling circulation low-temperature level compressor 14 absorbs the low-temp low-pressure in 4 exit of sub-cooled evaporator Refrigerant compresses it into the overheated gas of medium temperature and medium pressure, with the saturated gas of medium temperature cooling evaporator 3 and from liquid storage device 10 Enter medium temperature grade compressor 7 after the gas-liquid two-phase state working medium mixing of bypass, high temperature and high pressure gas is compressed into, into condenser 8 With air heat-exchange.It is that gas-liquid two-phase enters in liquid storage device 10 through the throttling of medium temperature grade throttle valve 9, realizes gas-liquid point in liquid storage device 10 From, liquid flows to evaporator, gas bypass into 7 suction line of high-temperature level compressor, with medium temperature cooling evaporator 3 outlet and Low-temperature level compressor 14, which exports after refrigerant is mixed together, enters medium temperature grade compressor 7.

Step 3: the gas-liquid two-phase fluid of medium temperature and medium pressure passes through medium temperature cooling evaporator 3 and CO₂Primary heat exchange is carried out to become The gas-liquid two-phase fluid of superheated vapor, low-temp low-pressure passes through sub-cooled evaporator 4 and CO₂It carries out secondary heat exchange and becomes overheat steaming Gas.It completes mechanical-assisted and crosses SAPMAC method.

Although the preferred embodiment of the present invention is described above in conjunction with attached drawing, the invention is not limited to upper The specific embodiment stated, the above mentioned embodiment is only schematical, be not it is restrictive, this field it is common Technical staff under the inspiration of the present invention, without breaking away from the scope protected by the purposes and claims of the present invention, may be used also By make it is many in the form of, within these are all belonged to the scope of protection of the present invention.