Adjustable multi-stage heat exchange jet type mixed working medium high-temperature heat pump system

Abstract

The invention relates to an adjustable multi-stage heat exchange injection type mixed working medium high-temperature heat pump system, and belongs to the technical field of high-temperature heat pump systems. The mixed working medium high-temperature heat pump system comprises a mixed working medium heat pump circulation loop and a gas-liquid jet type water supply loop. The mixed working medium heat pump circulation loop comprises a low-pressure compressor, a high-pressure compressor, working medium sides of four condensers, working medium sides of three evaporators and two two-phase ejectors, the working medium sides of the four condensers, the working medium sides of the three evaporators and the two two-phase ejectors are connected in series through two gas-liquid separators, and a working medium is a mixed working medium composed of cis-1, 3, 3, 3-tetrafluoropropene and isopentane. And the gas-liquid injection type water supply loop comprises a gas-liquid injector, a water pump and water sides of the three condensers. And the mixed working medium heat pump circulation loop and the gas-liquid jet type water supply loop are mutually coupled. The two gas-liquid separators are adopted to form four-stage condensation heat exchange, so that the energy utilization efficiency can be effectively improved, and the irreversible loss in the condensation process is reduced by at least 5%; evaporator evaporation of three different pressure levels is formed through boosting of the two two-phase ejectors, and irreversible loss in the evaporation process is reduced by at least 55%.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature heat pump systems, and in particular to a mixed working fluid high-temperature heat pump system that combines gas-liquid separation and regulation technology, ejector boosting technology and multi-stage heat exchange. Background Art

[0002] As global energy demand continues to rise, human dependence on fossil fuels has led to the severe challenge of global warming. As the main area of ​​energy consumption, the industrial sector accounts for 37% of the total global energy consumption. In the industrial production process, a large amount of heat is discharged in the form of waste heat, which is particularly significant in oil processing, power station cooling systems, mine drainage, and electroplating plants.

[0003] The emergence of high-temperature heat pump technology provides a solution to this problem. This technology can efficiently convert low-grade heat sources commonly found in production and life, such as wastewater, industrial waste heat cooling water, and natural water bodies, into higher-temperature heat energy by consuming a small amount of electricity. This heat energy can be used for building heating or process flows in a variety of industrial sectors, thereby achieving efficient use of energy. Therefore, this technology has great development potential and is expected to play an important role in global energy transformation and environmental protection.

[0004] Most existing heat pump cycles use pure working fluids. The isothermal characteristics of such working fluids during the phase change process lead to poor temperature matching between them and the variable temperature cold and heat sources. This mismatch increases the irreversible heat exchange loss during the cycle, thereby reducing the energy efficiency of the heat pump. Therefore, improving the temperature matching of the heat exchange process and reducing the irreversible heat exchange loss are the keys to improving the energy efficiency of the heat pump. The use of non-azeotropic mixed working fluids can improve the overall performance and flexibility of the system. Non-azeotropic mixed working fluids are mixtures of two or more pure working fluids (hereinafter collectively referred to as components) with different boiling points. The advantages of non-azeotropic mixed working fluids can be summarized as follows: The variable temperature phase change characteristics of non-azeotropic mixed working fluids, also known as temperature glide characteristics, can improve the temperature matching degree between the heat absorption and heat release processes and the heat source / cold source in the heat pump cycle, reduce heat exchange losses, and thus improve the energy efficiency of the system. A drying and dehumidification method based on a non-azeotropic mixed working fluid heat pump system utilizes the advantages of a non-azeotropic mixed working fluid heat pump system, and achieves efficient and energy-saving drying and deep dehumidification effects by precisely controlling the gas-liquid separation, heat exchange, and air circulation of high-boiling point and low-boiling point working fluids. This method not only improves the energy utilization efficiency of the heat pump system, but also meets the drying requirements of different stages through flexible temperature and humidity control, demonstrating the application potential of non-azeotropic mixed working fluids in heat pump technology. However, the inventors found that the potential of the current non-azeotropic mixed working fluid heat pump system is affected by the characteristics of the cold and heat sources. Once the heat pump cycle structure and working fluid are designed, the system can only be passively adjusted to adapt to the fluctuations of external working conditions. The temperature matching of the heat exchange process is prone to offset, resulting in limited performance improvement of the heat pump system. Therefore, the easy offset of temperature matching under variable working conditions limits the performance improvement of high-temperature heat pumps. If this problem can be solved, it can promote the rapid development of high-temperature heat pump technology.

[0005] Another way to improve the temperature matching of the heat exchange process is to use multi-stage heat exchange. Multi-stage heat exchange means that in the heat pump system, the heat exchange process is divided into multiple stages, each stage has its own specific temperature and pressure conditions. This method can reduce the heat loss caused by excessive temperature difference, thereby improving the system performance. The core of a multi-stage condensing heat pump system for producing high-temperature hot water lies in its multi-stage heat exchange design, including a working fluid circulation main loop and a working fluid branch, wherein the working fluid circulation main loop is sequentially provided with an evaporator, a compressor, a vortex tube refrigerator, a first heat exchanger, a second heat exchanger, a third heat exchanger and an expansion valve. The outlet of the vortex tube refrigerator is divided into two, and a part of the working fluid passes through the second and third heat exchangers through the working fluid branch, and then merges with the working fluid in the circulation main loop to achieve effective heat exchange. This multi-stage heat exchange design not only improves the heat exchange efficiency, but also can produce high-temperature hot water up to boiling temperature, meeting the demand for high-temperature hot water in industries and other fields. However, this system has the following problems: its cold water heating process is a linear temperature change process, and its working fluid heat exchange process is an isothermal process. Therefore, the temperature curves of the working fluid and the cold water are poorly matched, the irreversible heat exchange loss is large, and the energy efficiency improvement of the system is limited. Summary of the invention

[0006] In order to improve the energy efficiency of a mixed working fluid high temperature heat pump system, improve the temperature matching of the heat exchange process, and reduce heat exchange losses, the present invention provides an adjustable multi-stage heat exchange jet type mixed working fluid high temperature heat pump system.

[0007] The mixed working medium high temperature heat pump system of the present invention comprises: a mixed working medium heat pump circulation loop and a gas-liquid injection type water supply loop, and the two loops of the system are coupled to each other.

[0008] The mixed working fluid heat pump circulation loop includes a low-pressure compressor 1, a high-pressure compressor 11, a working fluid side of a first condenser 2, a working fluid side of a second condenser 3, a working fluid side of a third condenser 12, a working fluid side of a fourth condenser 13, a working fluid side of a first evaporator 6, a working fluid side of a second evaporator 8, a working fluid side of a third evaporator 10, a first gas-liquid separator 4, a second gas-liquid separator 14, a first two-phase ejector 7, and a second two-phase ejector 9; The exhaust port of the low-pressure compressor 1 is connected to the working medium inlet of the first condenser 2 and the air intake port of the high-pressure compressor 11 through a three-way pipe; The working fluid side outlet of the first condenser 2 is connected to the inlet of the first gas-liquid separator 4, the liquid outlet of the first gas-liquid separator 4 is connected to the working fluid inlet of the first two-phase ejector 7, and the gas outlet of the first gas-liquid separator 4 is connected to the working fluid side inlet of the second condenser 3; The exhaust port of the high-pressure compressor 11 is connected to the working fluid side inlet of the third condenser 12, the working fluid side outlet of the third condenser 12 is connected to the inlet of the second gas-liquid separator 14, the liquid outlet of the second gas-liquid separator 14 is connected to the working fluid inlet of the second two-phase ejector 9, the gas outlet of the second gas-liquid separator 14 is connected to the working fluid side inlet of the fourth condenser 13, and the working fluid side outlet of the fourth condenser 13 is respectively connected to the working fluid side outlet of the second condenser 3 and the inlet of the first throttle valve 5 through a three-way pipe; The outlet of the first throttle valve 5 is connected to the working fluid side inlet of the first evaporator 6, the working fluid side outlet of the first evaporator 6 is connected to the injection fluid inlet of the first two-phase ejector 7, the outlet of the first two-phase ejector 7 is connected to the working fluid side inlet of the second evaporator 8, the working fluid side outlet of the second evaporator 8 is connected to the injection fluid inlet of the second two-phase ejector 9, the outlet of the second two-phase ejector 9 is connected to the working fluid side inlet of the third evaporator 10, and the working fluid side outlet of the third evaporator 10 is connected to the suction port of the low-pressure compressor 1; The gas-liquid injection water supply circuit includes a gas-liquid injector 16, a water pump 17, a water side of the first condenser 2, a water side of the second condenser 3, a water side of the third condenser 12 and a water side of the fourth condenser 13; The ejection fluid inlet of the gas-liquid ejector 16 and the inlet of the water pump 17 are respectively connected to the two ports of the water inlet tee pipe; the outlet of the water pump 17 is connected to the working fluid inlet of the gas-liquid ejector 16 by being connected in series with the water side of the second condenser 3 and the water side of the first condenser 2 in sequence, and the outlet of the gas-liquid ejector 16 is connected in series with the water side of the fourth condenser 13 and the water side of the third condenser 12 in sequence, and the outlet of the water side of the third condenser 12 is a high-temperature steam discharge port; The working fluid inlet of the first two-phase ejector 7 and the working fluid inlet of the second two-phase ejector 9 are both high-pressure liquid working fluids, and the ejection fluid inlet of the first two-phase ejector 7 and the ejection fluid inlet of the second two-phase ejector 9 are both low-pressure gaseous working fluids; the working fluid inlet of the gas-liquid ejector 16 is a high-pressure gaseous working fluid, and the ejection fluid inlet of the gas-liquid ejector 16 is a low-pressure liquid working fluid; When working, the third port of the water inlet tee pipe is connected to the water supply pipe; The other side of the first evaporator 6, the other side of the second evaporator 8 and the other side of the third evaporator 10 connected in series are connected in series with the circulation pipe of the utilized waste heat circulating water; the working fluid side of the first evaporator 6, the working fluid side of the second evaporator 8 and the working fluid side of the third evaporator 10 realize heat exchange with the circulation pipe of the utilized waste heat circulating water.

[0009] The further technical solution is as follows: The working fluid of the mixed working fluid heat pump circulation loop is an environmentally friendly binary non-azeotropic mixture, which is uniformly mixed with 40% by mass of cis-1,3,3,3-tetrafluoropropylene and 60% by mass of isopentane; the critical temperature of the environmentally friendly binary non-azeotropic mixture is 148.9 o C. The ozone depletion index is 0, the global warming potential is less than 10, and the temperature slip is 8.75 at one atmosphere. o C, the temperature glide is 6.58 at 2000 kPa o C, the temperature glide is 4.3 at 3000 kPa o C.

[0010] The water pump 17 is a booster type water pump.

[0011] The pipelines of the mixed working medium high temperature heat pump system are all treated with thermal insulation.

[0012] The beneficial technical effects of the present invention are embodied in the following aspects: The proposed adjustable multi-stage heat exchange jet mixed working fluid high temperature heat pump system uses non-azeotropic mixed working fluid as the circulating working fluid, and combines two-stage compression, gas-liquid separation regulation and ejector-enhanced step-by-step pressure-boosting evaporation, which has the following advantages: 1. The gas-liquid separator of the present invention utilizes the different boiling points of the components of the non-azeotropic mixed working fluid to adjust the components to change the working fluid properties, and simultaneously forms multiple stages of condensation to increase the temperature glide of the overall condensation process. Figure 1 In the low-temperature condensation process, after the mixed working fluid is partially condensed in the first condenser 2, it enters the first gas-liquid separator 4 for gas-liquid separation and discharges the liquid working fluid, which adjusts the working fluid composition of the second condenser 3, thereby changing the temperature glide of the working fluid in the second condenser 3. At the same time, the temperature glide of the low-temperature condensation process is formed by the superposition of the temperature glides of the working fluids in the first condenser 2 and the second condenser 3. Similarly, in the high-temperature condensation process, after the mixed working fluid is partially condensed, it passes through the second gas-liquid separator 14 for gas-liquid separation and discharges the liquid working fluid, which adjusts the working fluid composition of the fourth condenser 13, and changes the temperature glide of the working fluid in the fourth condenser 13. The temperature glide of the high-temperature condensation process is formed by the superposition of the temperature glides of the working fluids in the third condenser 12 and the fourth condenser 33. Therefore, Figure 2 As shown, the temperature glide of the overall condensation process of the mixed working fluid high-temperature heat pump system is composed of the temperature glide of four sections of working fluid in the first condenser 2, the second condenser 3, the third condenser 12 and the fourth condenser 13. The temperature curve of the working fluid is more closely aligned with the temperature curve of the water supply, which greatly improves the temperature matching and reduces the irreversible loss of the condensation process by at least 5%, effectively improving the energy utilization efficiency.

[0013] 2. Evaporation in the evaporator with three different pressure levels is formed by boosting the pressure through a two-phase ejector. Figure 1 The working fluid is heated on the working fluid side of the first evaporator 6 and then enters the first two-phase ejector 7 for mixing, which increases the evaporation pressure and reduces the heat exchange temperature difference between the working fluid and the waste heat circulating water. After that, the working fluid enters the working fluid side of the second evaporator 8 for heating and then enters the second two-phase ejector 9 for mixing, which increases the evaporation pressure again and further reduces the heat exchange temperature difference between the working fluid and the waste heat circulating water. Figure 2 As shown in the figure, the overall evaporation process temperature curve of the mixed working fluid high-temperature heat pump system is jagged, and the temperature curve of the working fluid is more closely aligned with the temperature curve of the waste heat circulating water, which effectively improves the temperature matching of the evaporation process and can reduce the irreversible loss of the evaporation process by at least 55%.

[0014] 3. The water supply system uses a gas-liquid ejector 16 for mixed pressure boosting to reduce the power consumption of the water pump. Figure 1In the gas-liquid injection water supply system, the high-temperature water vapor at the water side outlet of the second condenser 2 is injected into the low-pressure water supply. The gas-liquid ejector 16 converts the latent heat released by the condensation of the high-temperature water vapor into pressure energy, which can increase the outlet pressure of the gas-liquid ejector without consuming mechanical work, so that the outlet pressure is increased by more than twice the inlet pressure. At the same time, the three-way pipe diverts part of the water supply, so that the water supply flow through the water pump 16 is reduced, further reducing the power consumption of the water pump. Therefore, combining the gas-liquid ejector 16 with the water supply system can reduce the energy consumption of the water supply system and reduce the pump power consumption by at least 91%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the adjustable multi-stage heat exchange jet type mixed working medium high temperature heat pump system of the present invention.

[0016] Figure 2 It is the temperature-heat load diagram of the heat exchange process of the adjustable multi-stage heat exchange jet mixed working fluid high temperature heat pump system.

[0017] Figure 3 Schematic diagram of the two-phase ejector structure.

[0018] Figure 4 This is a diagram showing the pressure variation in the two-phase ejector along the flow direction.

[0019] Figure 5 Schematic diagram of the gas-liquid ejector structure.

[0020] Figure 6 This is a diagram showing the pressure variation in the gas-liquid ejector along the flow direction.

[0021] Figure 7 This is the temperature-heat load diagram of the multi-stage condensation process.

[0022] Figure 8 This is the temperature-heat load diagram of the multi-stage evaporation process.

[0023] Fig. 9 This is the pressure-specific enthalpy diagram of the jet water supply system.

[0024] Serial numbers in the above figure: low-pressure stage compressor 1, high-pressure stage compressor 11, first condenser 2, second condenser 3, third condenser 12, fourth condenser 13, first evaporator 6, second evaporator 8, third evaporator 10, first gas-liquid separator 4, second gas-liquid separator 14, first throttle valve 5, second throttle valve 15, first two-phase ejector 7, second two-phase ejector 9, third gas-liquid ejector 16, water pump 17. DETAILED DESCRIPTION

[0025] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings.

[0026] See also Figure 1 A mixed working fluid high temperature heat pump system with adjustable multi-stage heat exchange injection type includes a mixed working fluid heat pump circulation loop and a gas-liquid injection water supply loop.

[0027] The mixed working fluid heat pump circulation loop includes a low-pressure stage compressor 1, a high-pressure stage compressor 11, a working fluid side of a first condenser 2, a working fluid side of a second condenser 3, a working fluid side of a third condenser 12, a working fluid side of a fourth condenser 13, a working fluid side of a first evaporator 6, a working fluid side of a second evaporator 8, a working fluid side of a third evaporator 10, a first gas-liquid separator 4, a second gas-liquid separator 14, a first two-phase ejector 7 and a second two-phase ejector 9.

[0028] The exhaust port of the low-pressure stage compressor 1 is connected to the working medium inlet of the first condenser 2 and the air intake port of the high-pressure stage compressor 11 through a three-way pipe.

[0029] The working fluid side outlet of the first condenser 2 is connected to the inlet of the first gas-liquid separator 4 , the liquid outlet of the first gas-liquid separator 4 is connected to the working fluid inlet of the first two-phase ejector 7 , and the gas outlet of the first gas-liquid separator 4 is connected to the working fluid side inlet of the second condenser 3 .

[0030] The exhaust port of the high-pressure compressor 11 is connected to the working fluid side inlet of the third condenser 12, the working fluid side outlet of the third condenser 12 is connected to the inlet of the second gas-liquid separator 14, the liquid outlet of the second gas-liquid separator 14 is connected to the working fluid inlet of the second two-phase ejector 9, the gas outlet of the second gas-liquid separator 14 is connected to the working fluid side inlet of the fourth condenser 13, and the working fluid side outlet of the fourth condenser 13 is respectively connected to the working fluid side outlet of the second condenser 3 and the inlet of the first throttle valve 5 through a three-way pipe.

[0031] The outlet of the first throttle valve 5 is connected to the working fluid side inlet of the first evaporator 6, the working fluid side outlet of the first evaporator 6 is connected to the induced fluid inlet of the first two-phase ejector 7, the outlet of the first two-phase ejector 7 is connected to the working fluid side inlet of the second evaporator 8, the working fluid side outlet of the second evaporator 8 is connected to the induced fluid inlet of the second two-phase ejector 9, the outlet of the second two-phase ejector 9 is connected to the working fluid side inlet of the third evaporator 10, and the working fluid side outlet of the third evaporator 10 is connected to the suction port of the low-pressure stage compressor 1.

[0032] The gas-liquid injection water supply circuit includes a gas-liquid injector 16, a water pump 17, a water side of the first condenser 2, a water side of the second condenser 3, a water side of the third condenser 12, and a water side of the fourth condenser 13. The water pump 17 is a booster type water pump.

[0033] The injection fluid inlet of the gas-liquid ejector 16 and the inlet of the water pump 17 are respectively connected to the two ports of the water inlet tee pipe; the outlet of the water pump 17 is connected to the working fluid inlet of the gas-liquid ejector 16 by being connected in series with the water side of the second condenser 3 and the water side of the first condenser 2 in sequence, and the outlet of the gas-liquid ejector 16 is connected in series with the water side of the fourth condenser 13 and the water side of the third condenser 12 in sequence, and the outlet of the water side of the third condenser 12 is a high-temperature steam exhaust port.

[0034] The working fluid inlet of the first two-phase ejector 7 and the working fluid inlet of the second two-phase ejector 9 are both high-pressure liquid working fluids, and the induced fluid inlet of the first two-phase ejector 7 and the induced fluid inlet of the second two-phase ejector 9 are both low-pressure gaseous working fluids; the working fluid inlet of the gas-liquid ejector 16 is a high-pressure gaseous working fluid, and the induced fluid inlet of the gas-liquid ejector 16 is a low-pressure liquid working fluid.

[0035] During operation, the third port of the water inlet tee is connected to the water supply pipe. The other side of the first evaporator 6, the other side of the second evaporator 8 and the other side of the third evaporator 10 are connected in series with the circulation pipeline of the waste heat circulating water to be utilized.

[0036] The working fluid of the mixed working fluid heat pump circulation loop is an environmentally friendly binary non-azeotropic mixture, which is uniformly mixed with 40% by mass of cis-1,3,3,3-tetrafluoropropylene and 60% by mass of isopentane; the critical temperature of the environmentally friendly binary non-azeotropic mixture is 148.9 o C. The ozone depletion index is 0, the global warming potential is less than 10, and the temperature slip is 8.75 at one atmosphere. o C, the temperature glide is 6.58 at 2000 kPa o C, the temperature glide is 4.3 at 3000 kPa o C.

[0037] The pipes of the mixed working fluid high temperature heat pump system are all treated with thermal insulation.

[0038] The working principle of the mixed working fluid high temperature heat pump system is as follows: During operation, the working fluid of the mixed working fluid heat pump circulation loop enters the low-pressure compressor 1 for pressurization into medium-pressure superheated gas, and enters two branches respectively; a part of the medium-pressure superheated gas enters the first condenser 2 for partial condensation to become a two-phase state, and the medium-pressure two-phase working fluid enters the first gas-liquid separator 4 for gas-liquid separation, and after separation, the high-boiling point medium-pressure saturated liquid enters the working fluid inlet of the first two-phase ejector 7, and the low-boiling point medium-pressure saturated gas enters the second condenser 3 to be completely condensed into a liquid; the other part of the medium-pressure superheated gas continues to be pressurized into high-pressure superheated gas in the high-pressure compressor 11, and enters the third condenser 12 for partial condensation to become a two-phase state, and the high-pressure two-phase working fluid enters the second gas-liquid separator 14 for gas-liquid separation, and after separation, the high-boiling point high-pressure saturated liquid enters the working fluid inlet of the second two-phase ejector 9, and the low-boiling point high-pressure saturated The gas enters the fourth condenser 13 to be completely condensed into liquid, and the high-pressure liquid working medium is isenthalpically reduced in pressure to become a two-phase fluid through the second throttle valve 15 and mixed with the medium-pressure liquid working medium at the outlet of the second condenser 3, and then enters the first evaporator 6 through the first throttle valve 5 to absorb heat and become a saturated gas, enters the injection fluid inlet of the first two-phase ejector 7, is mixed with the saturated liquid working medium at the working fluid inlet of the first two-phase ejector 7 for pressure increase, enters the second evaporator 8 through the outlet of the first two-phase ejector 7 to absorb heat and become a saturated gas, enters the injection fluid inlet of the second two-phase ejector 9, is mixed with the saturated liquid working medium at the working fluid inlet of the second two-phase ejector 9 for pressure increase, enters the third evaporator 10 through the outlet of the second two-phase ejector 9 to absorb heat and become a saturated gas, and finally returns to the inlet of the low-pressure stage compressor 1 to complete the cycle.

[0039] The water coming in from the water supply pipe in the gas-liquid injection water supply circuit is divided into two branches. A part of the low-pressure supply water is pressurized by the water pump 17 and enters the water side of the second condenser 3 and the water side of the first condenser 2 in turn to absorb heat as medium-pressure water vapor, and enters the gas-liquid ejector 16 from the working fluid inlet. The other part of the low-pressure water directly enters the gas-liquid ejector 16 from the ejection fluid inlet, is mixed and pressurized into a high-pressure fluid in the gas-liquid ejector 16, and then enters the fourth condenser 13 and the third condenser 12 in turn to absorb heat as high-pressure water vapor.

[0040] See also Figure 3 The two-phase ejector consists of a nozzle, a mixing chamber and a diffusion chamber, and the nozzle is a tapered type. Figure 4 The working fluid inlet of the two-phase ejector is a high-pressure liquid working medium, the ejection fluid inlet is a low-pressure gaseous working medium, and the outlet pressure of the two-phase ejector is between the pressure of the working fluid inlet and the pressure of the ejection fluid inlet.

[0041] See also Figure 5 The gas-liquid ejector consists of a nozzle, a mixing chamber and a diffusion chamber, and the nozzle is a gradually converging and expanding type. Figure 6The working fluid inlet is a high-pressure gaseous working medium, and the ejector fluid inlet is a low-pressure liquid working medium. After the two fluids are mixed, a condensation shock wave is formed at the end of the mixing chamber, and the pressure suddenly jumps, making the outlet pressure of the gas-liquid ejector higher than the pressure of the working fluid inlet.

[0042] Taking the heating process of heating 101.325kPa, 60℃ water to 400kPa, 150℃ water vapor as an example, the working process of the mixed working fluid high temperature heat pump system is explained: In the mixed working fluid heat pump circulation loop, the mixed working fluid composed of cis-1,3,3,3-tetrafluoropropylene and isopentane with a mass component ratio of 0.4:0.6 is pressurized to a medium-temperature medium-pressure gas of 1568.98 kPa by the low-stage compressor 1, and then enters two branches respectively; a part of the gas enters the first condenser 2 for isobaric condensation and heat release, and the dryness is set to 0.5. The working fluid is partially condensed into a two-phase state and enters the first gas-liquid separator 4 for gas-liquid separation. In the first gas-liquid separator 4, the density of the high-boiling-point component liquid of the two-phase working fluid is greater than that of the low-boiling-point component gas. At this time, the high-boiling-point component liquid with a mass component ratio of 0.32:0.68 will naturally settle to the lower layer, while the low-boiling-point component gas with a mass component ratio of 0.48:0.52 will float on the upper layer. The high-boiling-point component liquid discharged from the first gas-liquid separator 4 enters the working fluid inlet of the first two-phase ejector 7, and the low-boiling-point component gas enters the second condenser 3 for isobaric condensation and heat release and is completely condensed into a liquid state. The other part of the working fluid is pressurized into a high-temperature and high-pressure gas of 2712.13 kPa by the high-stage compressor 11, and enters the third condenser 12 for isobaric condensation and heat release. The dryness is set to 0.2. After the working fluid is partially condensed into a two-phase state, it enters the second gas-liquid separator 14 for gas-liquid separation. In the second gas-liquid separator 14, the density of the high-boiling-point component liquid of the two-phase working fluid is greater than that of the low-boiling-point component gas. The high-boiling-point component liquid with a mass component ratio of 0.38:0.62 is precipitated to the lower layer, and the low-boiling-point component gas with a mass component ratio of 0.48:0.52 floats on the upper layer. The high-boiling-point component liquid discharged from the second gas-liquid separator 14 enters the working fluid inlet of the second two-phase ejector 9, and the low-boiling-point component gas enters the fourth condenser 13 for isobaric condensation and heat release and is completely condensed into a liquid state, and then is isenthalpically reduced to 1568.98 kPa through the second throttle valve 15, and mixed with the working fluid from the working fluid inlet and outlet of the second condenser 3. The mixed working fluid passes through the first throttle valve 5 and isotropically depressurizes to 112 kPa. After isobaric evaporation and heat absorption on the working fluid side of the first evaporator 6 to become a gas, it enters the working fluid inlet of the first two-phase ejector 7 and mixes with the ejection fluid to increase the pressure to 130.26 kPa, and enters the second evaporator 8 to isobarically evaporate and absorb heat to become a gas. Then, the working fluid enters the working fluid inlet of the second two-phase ejector 9 and mixes with the ejection fluid to increase the pressure to 187.66 kPa, and the mass component ratio of the mixed working fluid is also restored to 0.4:0.6. The pressurized working fluid enters the third evaporator 10 to isobarically evaporate and absorb heat to become a gas, and finally returns to the inlet of the low-stage compressor 1 to complete the entire cycle.

[0043] Depend on Figure 7It can be seen that the dotted line is the water supply temperature curve of the gas-liquid injection water supply system, the dashed line is the unadjusted working fluid temperature curve of the condensation process, and the area enclosed by the temperature curves of the circulating working fluid and water can represent the irreversible loss. After adjustment, the final outlet temperature of the working fluid side of the second condenser 3 is 114.61℃, compared with the outlet temperature of the working fluid side of the medium-pressure condensation process 117.72℃ when not adjusted, the overall temperature glide increased by 3.11℃, and the irreversible loss of the medium-pressure condensation process was reduced by 2.79%; the outlet temperature of the working fluid side of the fourth condenser 3 is 146.18℃, compared with the outlet temperature of the working fluid side of the high-pressure condensation process 149.9℃ when not adjusted, the overall temperature glide increased by 3.72℃, the irreversible loss of the condensation process was reduced by 8.25%, and the irreversible loss of the overall condensation process was reduced by 5%.

[0044] Depend on Figure 8 It can be seen that the dotted line is the temperature curve of the waste heat circulating water, the dashed line is the unadjusted temperature curve of the working fluid in the evaporation process, and the realized line is the adjusted temperature curve of the working fluid in the evaporation process. The area enclosed by the temperature curves of the circulating working fluid and the waste heat circulating water can represent the irreversible loss. For the evaporation process, the pressure of the first evaporator 6 is 112 kPa, and the outlet temperature is 20.49 o C, the temperature glide is 1.36 o C; the pressure of the second evaporator 8 is 130.26 kPa, and the outlet temperature is 26.51 o C, the temperature glide is 0.82 o C; the pressure of the third evaporator 10 is 187.66 kPa, and the outlet temperature is 53.07 o C, the temperature glide is 15.24 o C, forming a three-stage sawtooth heat exchange temperature curve, compared with the evaporator working fluid outlet when not adjusted (pressure is 112kPa, temperature is 35.49 o C, the temperature glide is 16.36 o C), the irreversible loss in the evaporation process was reduced by 55.06%.

[0045] Depend on Fig. 9 It can be seen that the dotted line is the saturation line of the gas and liquid phases of water, the dashed line is the pressure-specific enthalpy change of the conventional water pump pressurized water supply, the solid line is the pressure-specific enthalpy change of the gas-liquid jet water supply system, and the dotted line is a schematic diagram of the gas-liquid jet mixing process. The inlet temperature of the conventional water pump pressurized water supply is 60 o C, the pressure is 101.325 kPa, and after being pressurized to 400 kPa by a water pump, isobaric evaporation is performed with an endothermic heat of 150 o C water vapor, taking the production of 1000kg water vapor as an example, the pump power consumption is 405.01kW. In the gas-liquid injection water supply system, the water inlet temperature is 60 oC, the pressure is 101.325kPa, and the water supply is divided into two branches through a three-way pipe, and the flow ratio of the two branches is 1:1. One part of the water supply is pressurized to 150kPa by a water pump, and enters the water side of the second condenser 3 and the water side of the first condenser 2 to absorb heat at isobaric pressure to become saturated water vapor, and then enters the working fluid inlet of the gas-liquid ejector 16; the other part of the water supply directly enters the ejection fluid inlet of the gas-liquid ejector 16, and the fluids of the two branches are mixed in the gas-liquid ejector 16 to increase the pressure to 400kPa high-pressure fluid, and enter the fourth condenser 13 and the third condenser 12 in turn to absorb heat to 150kPa o C of water vapor. The boost pressure of the water pump during the gas-liquid ejector boost water delivery process is reduced by 250kPa, and the water flow through the water pump is reduced by 50%. Taking the production of 1000kg of water vapor as an example, the pump power consumption of the jet water supply system is only 33kW, which can save 91.85% of the power consumption compared to the conventional pumping water delivery process.

[0046] It will be easily understood by those skilled in the art that the above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An adjustable multi-stage heat exchange jet type mixed working medium high temperature heat pump system, characterized in that: include: Mixed working medium heat pump circulation loop and gas-liquid injection water supply loop; The mixed working fluid heat pump circulation loop comprises a low-pressure compressor (1), a high-pressure compressor (11), a working fluid side of a first condenser (2), a working fluid side of a second condenser (3), a working fluid side of a third condenser (12), a working fluid side of a fourth condenser (13), a working fluid side of a first evaporator (6), a working fluid side of a second evaporator (8), a working fluid side of a third evaporator (10), a first gas-liquid separator (4), a second gas-liquid separator (14), a first two-phase ejector (7), and a second two-phase ejector (9); The exhaust port of the low-pressure compressor (1) is connected to the working medium inlet of the first condenser (2) and the air intake port of the high-pressure compressor (11) respectively through a three-way pipe; The working fluid side outlet of the first condenser (2) is connected to the inlet of the first gas-liquid separator (4), the liquid outlet of the first gas-liquid separator (4) is connected to the working fluid inlet of the first two-phase ejector (7), and the gas outlet of the first gas-liquid separator (4) is connected to the working fluid side inlet of the second condenser (3); The exhaust port of the high-pressure compressor (11) is connected to the working fluid side inlet of the third condenser (12), the working fluid side outlet of the third condenser (12) is connected to the inlet of the second gas-liquid separator (14), the liquid outlet of the second gas-liquid separator (14) is connected to the working fluid inlet of the second two-phase ejector (9), the gas outlet of the second gas-liquid separator (14) is connected to the working fluid side inlet of the fourth condenser (13), and the working fluid side outlet of the fourth condenser (13) is respectively connected to the working fluid side outlet of the second condenser (3) and the inlet of the first throttle valve (5) through a three-way pipe; The outlet of the first throttle valve (5) is connected to the working fluid side inlet of the first evaporator (6), the working fluid side outlet of the first evaporator (6) is connected to the injection fluid inlet of the first two-phase ejector (7), the outlet of the first two-phase ejector (7) is connected to the working fluid side inlet of the second evaporator (8), the working fluid side outlet of the second evaporator (8) is connected to the injection fluid inlet of the second two-phase ejector (9), the outlet of the second two-phase ejector (9) is connected to the working fluid side inlet of the third evaporator (10), and the working fluid side outlet of the third evaporator (10) is connected to the suction port of the low-pressure compressor (1); The gas-liquid injection water supply circuit comprises a gas-liquid injector (16), a water pump (17), a water side of a first condenser (2), a water side of a second condenser (3), a water side of a third condenser (12), and a water side of a fourth condenser (13); The ejection fluid inlet of the gas-liquid ejector (16) and the inlet of the water pump (17) are respectively connected to two ports of the water inlet tee pipe; the outlet of the water pump (17) is connected to the working fluid inlet of the gas-liquid ejector (16) by being connected in series with the water side of the second condenser (3) and the water side of the first condenser (2) in sequence; the outlet of the gas-liquid ejector (16) is connected in series with the water side of the fourth condenser (13) and the water side of the third condenser (12) in sequence; the outlet of the water side of the third condenser (12) is a high-temperature steam discharge outlet; The working fluid inlet of the first two-phase ejector (7) and the working fluid inlet of the second two-phase ejector (9) are both high-pressure liquid working fluids, and the ejection fluid inlet of the first two-phase ejector (7) and the ejection fluid inlet of the second two-phase ejector (9) are both low-pressure gaseous working fluids; the working fluid inlet of the gas-liquid ejector (16) is a high-pressure gaseous working fluid, and the ejection fluid inlet of the gas-liquid ejector (16) is a low-pressure liquid working fluid; When working, the third port of the water inlet tee pipe is connected to the water supply pipe; The other side of the first evaporator (6), the other side of the second evaporator (8) and the other side of the third evaporator (10) connected in series are connected in series with a circulation pipeline of the waste heat circulating water to be utilized; the working fluid side of the first evaporator (6), the working fluid side of the second evaporator (8) and the working fluid side of the third evaporator (10) achieve heat exchange with the circulation pipeline of the waste heat circulating water to be utilized.

2. The adjustable multi-stage heat exchange jet type mixed working medium high temperature heat pump system according to claim 1, characterized in that: The working fluid of the mixed working fluid heat pump circulation loop is an environmentally friendly binary non-azeotropic mixture, which is uniformly mixed with 40% by mass of cis-1,3,3,3-tetrafluoropropylene and 60% by mass of isopentane; the critical temperature of the environmentally friendly binary non-azeotropic mixture is 148.9 o C. The ozone depletion index is 0, the global warming potential is less than 10, and the temperature slip is 8.75 at one atmosphere. o C, the temperature glide is 6.58 at 2000 kPa o C, the temperature glide is 4.3 at 3000 kPa o C.

3. The adjustable multi-stage heat exchange jet type mixed working medium high temperature heat pump system according to claim 1, characterized in that: The water pump (17) is a booster type water pump.

4. The adjustable multi-stage heat exchange jet type mixed working medium high temperature heat pump system according to claim 1, characterized in that: The pipelines of the mixed working medium high temperature heat pump system are all treated with thermal insulation.

Images