CN114791179A - Solar waste heat driven jet refrigeration coupling system and method - Google Patents

Abstract

The invention discloses a solar energy waste heat driven jet refrigeration coupling system and method. The system includes a solar heat collection generating sub-cycle and a jet compression sub-cycle, the water absorbing solar radiation exchanges heat with the refrigerant in the generator, and the liquid refrigerant circulates heat; In the generator, it absorbs heat and vaporizes into a high-temperature and high-pressure refrigerant, which enters the ejector as a primary fluid, injects a secondary fluid mixed with the refrigerant in the compressor, and mixes in the ejector for boosting. Part of the refrigerant discharged during the compression process of the compressor is mixed with the gaseous refrigerant in the gas-liquid separator and then enters the ejector, which reduces the power consumption of the compressor and effectively improves the refrigeration performance of the system. This system is superior to the ordinary solar injection refrigeration system and compression. Cooling System.

Description

A solar energy waste heat driven jet refrigeration coupling system and method

technical field

The invention belongs to the field of new energy waste heat utilization, and in particular relates to a novel solar energy waste heat driven jet refrigeration coupling system and method.

Background technique

In the past half century, my country's industry has developed by leaps and bounds, and the level of the national economy has been significantly improved. On the one hand, my country's demand for energy continues to increase. It has become the focus of attention and research in all walks of life, especially in the construction industry. In my country, the building energy consumption per unit area of windows, exterior walls and roofs is 2 to 3 times, 3 to 5 times, and 3 to 5 times that of developed countries, respectively. The actual energy consumption of air conditioners and the energy consumption of building heating in winter are In general, it is much higher than that of developed countries, while the per capita value of coal and water resources in my country is 1/2 of the world average, and the per capita value of oil and natural gas is only 4.1% of the world average. Higher energy usage and lower energy utilization have brought heavy pressure on my country's energy supply.

Research and development of refrigeration and air-conditioning systems and devices driven by renewable energy or low-grade thermal energy is one of the important directions for the development of the refrigeration and air-conditioning industry, and it is also an important measure to adapt to the national energy-saving emission reduction and low-carbon development strategy.

my country has a vast territory and is very rich in solar energy resources. As an inexhaustible natural resource, solar energy is clean and cheap, so it is widely used in refrigeration systems, including photoelectric conversion, that is, solar energy is converted into electricity, and then Drive conventional compression refrigeration system; photothermal conversion, first convert solar energy into thermal energy, and then carry out refrigeration by absorption, adsorption or injection. Among them, the solar injection refrigeration system has a simple system structure, reliable operation, and improves system efficiency At the same time, it does not increase the complexity of the system, and the cooling capacity of the system is highly matched with the intensity of solar radiation, so the development potential is high.

An ejector is a device that uses the mixing of two fluids in different states to generate intermediate pressure fluids to complete energy exchange and mass transfer. Because the ejector has the characteristics of simple structure, stable operation and no moving parts, the ejector can be widely used in many fields such as pharmacy, chemical industry and energy. At present, in the refrigeration system coupled with injection and compression driven by solar waste heat, when the condensing temperature decreases or the evaporating temperature increases, the external pressure ratio of the compressor decreases. For a fixed compressor, since the internal pressure ratio is constant, the external pressure ratio is smaller than the internal pressure. The compressor is over-compressed when compared, which reduces the efficiency of the compressor and reduces the overall performance of the system.

In conclusion, there is an urgent need to propose a refrigeration system and method that couples injection and compression to make full use of solar energy waste heat, reduce compression power consumption, and improve system performance.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide an ejection refrigeration coupling system driven by solar waste heat. Due to the current solar waste heat driven refrigeration system coupled with injection and compression, the compression power consumption is large, and for a fixed compressor, due to a fixed internal pressure ratio, when the external pressure ratio is smaller than the internal pressure ratio, the compressor is over-compressed, reducing the compression rate. The efficiency of the machine decreases the overall performance of the system. In order to solve this problem, the present invention proposes a new type of injection refrigeration coupling system driven by solar energy waste heat, through which part of the refrigerant discharged during the compression process of the compressor is mixed with the gaseous refrigerant in the gas-liquid separator and then enters the ejector to reduce the cooling rate. Compressor power consumption improves system performance.

The present invention is achieved through the following technical solutions.

In one aspect of the present invention, there is provided a solar energy waste heat driven jet refrigeration coupling system, comprising a solar heat collection generating sub-cycle and an jet compression sub-cycle;

The solar heat collection generation sub-cycle includes a circulation loop composed of a generator, a water pump and a solar heat collector; the water absorbing solar radiation exchanges heat with the refrigerant in the generator;

The jet compression sub-cycle includes a first jet compression sub-cycle loop consisting of a generator, an ejector, and a condenser communicating with the generator; communicating with the second injection compression sub-circulation loop formed by the injector;

The liquid refrigerant absorbs heat and vaporizes into a high-temperature and high-pressure refrigerant in the generator, enters the ejector as a primary fluid, injects a secondary fluid mixed with the refrigerant in the compressor, and mixes in the ejector for boosting.

A further improvement of the present invention is that the gas-liquid two-phase mixture in the gas-liquid separator is separated into saturated gaseous refrigerant and saturated liquid refrigerant, which are respectively discharged from the upper and lower pipelines in the gas-liquid separator.

A further improvement of the present invention is that the upper pipeline of the gas-liquid separator and the pipeline of the compressor through the regulating valve are jointly connected to the ejector.

A further improvement of the present invention is that the lower pipeline of the gas-liquid separator is connected to the compressor through the second throttle valve and the evaporator.

A further improvement of the present invention is that the outlet pipeline of the ejector is communicated with the compressor, then communicated with the condenser, and communicated with the generator through the working fluid pump.

A further improvement of the present invention is that the outlet of the condenser communicates with the gas-liquid separator through the first throttle valve.

A further improvement of the present invention is that the injector includes a nozzle, a suction chamber, a mixing chamber and a diffusing chamber, the mixing chamber is an equal diameter section, and the suction chamber and the diffusing chamber are located at both ends of the mixing chamber and are expanding diameter sections; It is connected to the outlet of the generator, one end extends into the throat of the suction chamber, and the side wall of the suction chamber is connected to the gas-liquid separator; the tail of the diffuser chamber is the outlet of the ejector.

Another aspect of the present invention provides a method for coupling jet refrigeration driven by the solar waste heat of the system. Water absorbs solar radiation heat in the solar collector and then enters the generator to exchange heat with the refrigerant, and then returns to the solar collector. in the heater;

The liquid refrigerant absorbs heat and vaporizes in the generator to become a high temperature and high pressure refrigerant, and enters the ejector as a primary fluid;

The saturated gaseous refrigerant from the gas-liquid separator and the refrigerant discharged from the compressor are mixed into the secondary fluid of the ejector and injected, and the two fluids are mixed in the ejector to boost pressure;

The saturated liquid refrigerant from the gas-liquid separator flows into the evaporator after adiabatic throttling to absorb heat and then returns to the compressor;

The refrigerant at the outlet of the ejector is mixed with the gaseous refrigerant at the outlet of the compressor, and enters the condenser to condense and release heat. Part of the refrigerant is boosted by the working fluid pump and then returned to the generator; After the flow, it is in the state of wet steam and is sent to the gas-liquid separator for gas-liquid separation.

A further improvement of the present invention is that the high-pressure primary fluid ejected by the ejector enters the suction chamber of the ejector, the suction area generates a vacuum, and the secondary fluid is ejected, the two fluids are mixed in the mixing chamber, and the ejector outlet in the diffusing chamber The pressure is higher than the pressure of the secondary fluid entering the suction chamber.

Compared with the prior art, the present invention has the following beneficial effects:

In the existing injection-compression coupled refrigeration system, when the condensing temperature decreases or the evaporating temperature increases, the external pressure ratio of the compressor decreases. For a fixed compressor, since the internal pressure ratio is constant, the external pressure ratio is smaller than the internal pressure ratio. The compressor is over-compressed, which reduces the efficiency of the compressor and reduces the overall performance of the system. In order to improve the utilization rate of solar energy and improve the over-compression situation of the compressor, the present invention proposes a coupled refrigeration system of injection and intermediate exhaust compression driven by solar energy waste heat. During the compression process of the compressor, part of the refrigerant is discharged and the gaseous refrigerant in the gas-liquid separator is discharged. After mixing, it enters the ejector to reduce the power consumption of the compressor, which can effectively improve the performance of the system, and the performance of the system is better than the ordinary solar ejector refrigeration system and compression refrigeration system.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of this application, and do not constitute an improper limitation of the present invention. In the accompanying drawings:

1 is a schematic diagram of a solar waste heat driven jet refrigeration coupling system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a simplified model of injection refrigeration according to an embodiment of the present invention.

1, generator; 2, water pump; 3, solar collector; 4, ejector; 401, primary fluid inlet; 402, secondary fluid inlet; 403, nozzle; 404, throat; 405, suction chamber; 406, Mixing chamber; 407, diffuser chamber; 408, shock point; 409, ejector outlet; 5, condenser; 6, first throttle valve; 7, gas-liquid separator; 8, second throttle valve; 9 , evaporator; 10, compressor; 11, regulating valve; 12, working fluid pump.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

Please refer to FIG. 1. FIG. 1 shows a solar waste heat driven jet refrigeration coupling system according to an embodiment of the present invention, including a solar heat collection generation sub-cycle and an jet compression sub-cycle. Among them, the solar heat collection generation sub-cycle includes a circulation loop composed of a generator 1, a water pump 2 and a solar heat collector 3; wherein, after the water absorbs the heat of solar radiation in the solar heat collector 3 and the temperature rises, it enters the generator It exchanges heat with the refrigerant in 1, and then returns to the solar collector 3 through the action of the water pump 2.

The injection compression sub-cycle includes a route generator 1, an ejector 4, a condenser 5, a working fluid pump 12 and then connected to the generator 1 to form a first injection compression sub-cycle; the outlet pipeline of the ejector 4 is communicated with the compressor 10, and then The condenser 5 is communicated, and the generator 1 is communicated through the working fluid pump 12 . On the other hand, the ejector 4, the condenser 5 and the first throttle valve 6 are connected to the second throttle valve 8, the evaporator 9 and the compressor 10 through the lower pipeline of the gas-liquid separator 7 to the condenser 5 and the upper part of the separator 7 The pipeline is directly connected to the injector 4 to form a second injection compression sub-circulation loop.

Wherein, the gas-liquid two-phase mixture in the gas-liquid separator 7 is separated into a saturated gaseous refrigerant and a saturated liquid refrigerant, which are respectively discharged from the upper and lower pipelines in the gas-liquid separator. The upper pipeline of the gas-liquid separator 7 and the pipeline of the compressor 10 are jointly connected to the ejector 4 through the pipeline of the regulating valve 11; the lower pipeline of the gas-liquid separator 7 is connected to the compressor 10 through the second throttle valve 8 and the evaporator 9. .

In the injection compression sub-cycle, the liquid refrigerant absorbs heat and vaporizes into a high temperature and high pressure refrigerant in the generator 1, enters the ejector 4 as a primary fluid, injects the secondary fluid of the ejector, and the two fluids are mixed in the ejector. pressure, and then mixed with the gaseous refrigerant at the outlet of the compressor 10, and then enters the condenser 5 to condense and release heat; a part of the refrigerant is boosted by the working fluid pump 12 and then returned to the generator 1, and the other part of the refrigerant is throttled at the first throttling After adiabatic throttling in the valve 6, it enters the gas-liquid separator 7 in a wet vapor state, and the saturated gaseous refrigerant from the gas-liquid separator 7 is mixed with the refrigerant discharged from the middle of the compressor 10 and is used as the secondary fluid of the ejector. Ejection; the saturated liquid refrigerant from the gas-liquid separator 7 flows into the evaporator 9 after adiabatic throttling by the second throttle valve 8, absorbs external heat, and returns to the compressor 10 to complete the entire cycle.

Please refer to FIG. 2. FIG. 2 shows a schematic structural diagram of an injection refrigeration system according to an embodiment of the present invention. An ejector is a device that uses the mixing of two fluids in different states to generate intermediate pressure fluids to complete energy exchange and mass transfer. Because the ejector has the characteristics of simple structure, stable operation and no moving parts. The ejector includes four parts: the nozzle 403, the suction chamber 405, the mixing chamber 406 and the diffusing chamber 407; the mixing chamber 406 is an equal diameter section, and the suction chamber 405 and the diffusing chamber 407 are located at both ends of the mixing chamber 406, which are the expanding section, The primary fluid inlet 401 at one end of the nozzle 403 is connected to the generator outlet, and one end extends into the throat 404 of the suction chamber 405. The side wall of the suction chamber 405 is provided with a secondary fluid inlet 402 that communicates with the gas-liquid separator 7; in the middle of the mixing chamber 406 is Shock point 408; the end of the diffuser chamber 407 is the ejector outlet 409.

The solar energy waste heat driven jet refrigeration coupling method provided by the present invention includes:

Water absorbs solar radiation heat in the solar collector and heats up, enters the generator to exchange heat with the refrigerant, and then returns to the solar collector; the liquid refrigerant absorbs heat and vaporizes into a high-temperature and high-pressure refrigerant in the generator, which is used as a primary fluid into the injector.

The other part of the refrigerant at the outlet of the condenser 5 is in a wet vapor state after adiabatic throttling in the first throttle valve 6, and is sent to the gas-liquid separator 7 for gas-liquid separation.

The function of the gas-liquid separator is to separate the gas-liquid two-phase mixture into a saturated gaseous refrigerant and a saturated liquid refrigerant. The upper pipeline is discharged, and the saturated liquid refrigerant is discharged from the lower pipeline in the gas-liquid separator.

The saturated gaseous refrigerant from the gas-liquid separator and the refrigerant discharged from the compressor are mixed into the secondary fluid of the ejector and injected, and the two fluids are mixed in the ejector to boost pressure;

The saturated liquid refrigerant from the gas-liquid separator flows into the evaporator 9 after adiabatic throttling by the second throttle valve 8, absorbs external heat, and returns to the compressor to complete the entire cycle.

The refrigerant at the outlet of the ejector is mixed with the gaseous refrigerant at the outlet of the compressor, and enters the condenser to condense and release heat. Part of the refrigerant is boosted by the working fluid pump and then returned to the generator; After the flow, it is in the state of wet steam and is sent to the gas-liquid separator for gas-liquid separation.

When the ejector is working, the high-pressure primary fluid ejected from the nozzle 403 through the primary fluid inlet 401 enters the suction chamber 405 of the ejector. Due to the extremely high flow rate of the ejected fluid, the pressure energy is converted into velocity energy, and the pressure in the suction area is reduced to generate a vacuum. , and then inject the secondary fluid, the two fluids exchange energy in the mixing chamber 406, and enter the diffuser chamber 407 after being fully mixed. The pressure is higher than the pressure of the secondary fluid entering the suction chamber, thereby increasing the pressure of the secondary fluid.

The process of the primary fluid from the nozzle inlet to the throat is an isentropic process, namely:

where h _p,0 and h _t are the specific enthalpy of the primary fluid at the injector inlet and throat, respectively, and v _t is the velocity of the primary fluid at the nozzle throat, m/s.

In the ejector model, the isentropic efficiency is generally used to measure the energy loss in the ejector, since the isentropic efficiencies corresponding to different refrigerants are different.

The compressor adopts a scroll compressor with intermediate exhaust, which consists of a movable scroll, a stationary scroll, a suction hole, an intermediate exhaust hole and an exhaust hole. The two scrolls with the same parameters of the scroll profile and the distance between the centers of the two base circles are r (the value of r is related to the involute pitch and wall thickness), but the two scrolls with a phase difference of π are the movable scrolls respectively. After being assembled with the static scroll, several pairs of crescent-shaped closed volume cavities can be formed.

The gas after the first stage compression of the compressor is higher than the saturated gaseous refrigerant in the gas-liquid separator, so under the action of the pressure difference, part of the gas is discharged from the intermediate exhaust hole of the compressor and separated from the gas-liquid After the refrigerant gas in the ejector is mixed, the secondary fluid as the ejector enters the ejector. In the process of intermediate exhaust of the compressor, the rotation angle of the main shaft continues to increase, and the compression process continues. Since the pressure in the compressor is always higher than the external pressure during this process, the gas in the compressor continues to move toward the outside. out.

When the condensing temperature decreases or the evaporating temperature increases, the external pressure ratio of the compressor decreases. The method of the invention overcomes the problem of over-compression of the fixed compressor when the external pressure ratio is smaller than the internal pressure ratio due to a fixed internal pressure ratio. condition, improve the efficiency of the compressor and improve the overall performance of the system.

The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical contents without creative work. Modifications, replacements and modifications are all within the protection scope of the present invention.

Claims (10)

1. A solar energy waste heat driven injection refrigeration coupling system is characterized by comprising a solar energy heat collection generation sub-cycle and an injection compression sub-cycle;

the solar heat collection generation sub-cycle comprises a circulation loop formed by a generator (1), a water pump (2) and a solar heat collector (3); the water absorbing the solar radiation exchanges heat with the refrigerant in the generator in a circulating way;

the injection compression sub-cycle comprises a first injection compression sub-cycle loop formed by communicating a generator (1), an injector (4) and a condenser (5) with the generator (1); and a second injection compression sub-circulation loop which is formed by respectively communicating the ejector (4) with the condenser (5) through a gas-liquid separator (7) and communicating the evaporator (9) with the compressor (10) to the condenser (5) and the ejector (4);

the liquid refrigerant absorbs heat in the generator and is vaporized into high-temperature and high-pressure refrigerant, the high-temperature and high-pressure refrigerant is used as primary fluid to enter the ejector, secondary fluid mixed with the refrigerant in the compressor is ejected and mixed in the ejector to be boosted.

2. The solar waste heat driven jet refrigeration coupling system as claimed in claim 1, wherein the gas-liquid two-phase mixture in the gas-liquid separator (7) is separated into a saturated gas refrigerant and a saturated liquid refrigerant, and the saturated gas refrigerant and the saturated liquid refrigerant are respectively discharged from an upper pipeline and a lower pipeline in the gas-liquid separator.

3. The solar afterheat-driven jet refrigeration coupling system as claimed in claim 2, wherein the upper pipeline of the gas-liquid separator (7) and the compressor (10) are communicated with the ejector (4) through the pipeline of the regulating valve (11).

4. The solar waste heat driven jet refrigeration coupling system as claimed in claim 2, wherein the lower pipeline of the gas-liquid separator (7) is communicated to the compressor (10) through a second throttle valve (8) and an evaporator (9).

5. The solar waste heat driven jet refrigeration coupling system as claimed in claim 1, wherein an outlet pipeline of the jet device (4) is communicated with a compressor (10), then communicated with a condenser (5) and communicated with the generator (1) through a working medium pump (12).

6. A solar waste heat driven jet refrigeration coupling system according to claim 1, characterized in that the outlet of the condenser (5) is connected with the gas-liquid separator (7) through the first throttle valve (6).

7. The solar waste heat driven jet refrigeration coupling system as claimed in claim 1, wherein the ejector comprises a nozzle (403), a suction chamber (405), a mixing chamber (406) and a diffuser chamber (407), the mixing chamber (406) is a constant diameter section, and the suction chamber (405) and the diffuser chamber (407) are located at two ends of the mixing chamber (406) and are diameter-expanded sections; one end of the nozzle (403) is communicated with the outlet of the generator, and the other end of the nozzle extends into the throat part (404) of the suction chamber (405), and the side wall of the suction chamber (405) is connected with the gas-liquid separator (7); the diffuser chamber (407) terminates in an ejector outlet (409).

8. A solar waste heat driven injection refrigeration coupling method based on the system of any one of claims 1 to 7, which is characterized by comprising the following steps: .

The water absorbs solar radiation heat in the solar heat collector, is heated, enters the generator to exchange heat with the refrigerant, and then returns to the solar heat collector;

the liquid refrigerant absorbs heat in the generator and is vaporized into high-temperature and high-pressure refrigerant, and the high-temperature and high-pressure refrigerant is used as primary fluid to enter the ejector;

the saturated gaseous refrigerant from the gas-liquid separator and the refrigerant discharged from the compressor are mixed into a secondary fluid of the ejector and are injected, and the two fluids are mixed in the ejector and are pressurized;

the saturated liquid refrigerant from the gas-liquid separator flows into the evaporator after heat insulation throttling to absorb heat and then returns to the compressor;

the refrigerant at the outlet of the ejector is mixed with the gaseous refrigerant at the outlet of the compressor, the mixture enters the condenser to be condensed and release heat, and a part of the refrigerant returns to the generator after being boosted by the working medium pump; the other part of the refrigerant at the outlet of the condenser is in a wet steam state after heat insulation throttling and is sent into a gas-liquid separator for gas-liquid separation.

9. The system of claim 8, wherein the high pressure primary fluid from the ejector enters the suction chamber of the ejector, the suction area creates a vacuum to draw the secondary fluid, the two fluids are mixed in the mixing chamber, and the pressure at the outlet of the ejector in the diffusion chamber is higher than the pressure of the secondary fluid entering the suction chamber.

10. The system of claim 9, wherein the process of the primary fluid from the nozzle inlet to the throat is an isentropic process, that is:

wherein h is _p,0 And h _t Specific enthalpy, v, of primary fluid at the inlet and throat of the ejector, respectively _t Is the velocity of the primary fluid at the throat of the nozzle.

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