Ejector-compression sewage source heat pump system based on large slip temperature non-azeotropic working fluid

Abstract

The application discloses a kind of based on big slip temperature non-azeotropic working medium injection-compression sewage source heat pump system, including compressor, first condenser, gas-liquid separator, second condenser, throttle valve, first evaporator, ejector, second evaporator, hot water outlet end, hot water import end, sewage outlet end, sewage import end;Gas-liquid separator's first inlet end is connected with the first inlet end of ejector, and the first outlet end of first evaporator is connected with the second inlet end of ejector, and the outlet end of ejector is connected with the first inlet end of second evaporator.The injection-compression sewage source heat pump system with big slip temperature non-azeotropic refrigerant as circulating working medium, using the big slip temperature characteristics of non-azeotropic working medium when phase change at constant pressure reduces heat transfer temperature difference, and through two-stage condensation and variable component concentration control improves compressor suction pressure, reduces suction and exhaust pressure ratio, further improves system performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat pumps, and relates to a jet-compression sewage source heat pump system based on a large-slippage temperature non-azeotropic working medium. BACKGROUND

[0002] Compared with the traditional compression heat pump cycle, the jet-compression sewage source heat pump system with a single working medium integrates an ejector into a vapor compression cycle, uses the low-grade waste heat of sewage to drive the ejector as a primary expansion device to recover part of the expansion work of the throttling valve, reduces the irreversible loss related to the expansion device, on the other hand, improves the suction pressure of the compressor, reduces the compression work, and thus improves the system performance.

[0003] However, the standard jet-compression refrigeration cycle also has the problem of low efficiency, and therefore the use of a non-azeotropic jet-compression refrigeration cycle can effectively improve the cycle performance.

[0004] The existing non-azeotropic mixed working medium can realize a near-Lorentz cycle due to the temperature slippage generated during the constant-pressure phase change, and compared with the reverse Carnot cycle of the traditional working medium, the use of the non-azeotropic mixed working medium can improve the temperature matching in the heat exchange process, the irreversible loss is smaller, and the system performance can be improved. However, the non-azeotropic mixed working medium cannot completely match the requirements of the working medium characteristics under different working conditions at a fixed component concentration ratio, and therefore under certain working conditions, the system cycle performance sharply decreases, and the non-azeotropic working medium causes the heat transfer temperature difference and the heat transfer coefficient to decrease, resulting in a decrease in the cycle efficiency and an ineffective improvement in the system energy efficiency. SUMMARY

[0005] Technical problem: To solve the above problems in the prior art, the purpose of the present application is to provide a jet-compression sewage source heat pump system based on a large-slippage temperature non-azeotropic working medium, which realizes step-by-step condensation and variable component concentration regulation by using the large-slippage temperature non-azeotropic working medium, so as to further improve the suction pressure of the compressor, reduce the power consumption of the compressor, and effectively improve the performance of the sewage source heat pump system.

[0006] Technical solution: To achieve the above purpose, the present application adopts the following technical solution, which comprises an ejector and a first evaporator connected to the ejector, separates the liquid mixed two-phase state refrigerant in the system into a mixed working medium saturated liquid refrigerant of high high-boiling point working medium components and a saturated liquid refrigerant of high low-boiling point working medium components;

[0007] The mixed working medium saturated liquid refrigerant of high high-boiling point working medium components is fed into the ejector; the saturated liquid refrigerant of high low-boiling point working medium components is fed into the first evaporator to generate a mixed working medium saturated gaseous refrigerant of high low-boiling point working medium components through the first evaporator;

[0008] The mixed refrigerant of high-high boiling point component in saturated liquid state is expanded into two-phase state through the nozzle of the ejector, and injects the mixed refrigerant of high-low boiling point component in saturated gaseous state from the first evaporator.

[0009] Further, the system comprises a compressor, a first condenser, a gas-liquid separator, a second condenser, a first evaporator, an ejector and a second evaporator.

[0010] The compressor sucks in the mixed refrigerant in saturated state, and compresses the mixed refrigerant into high-temperature and high-pressure non-azeotropic mixed refrigerant, which is cooled into gaseous-liquid two-phase state refrigerant through the first condenser, and flows into the gas-liquid separator, and is separated into the mixed refrigerant of high-low boiling point component in saturated gaseous state and the mixed refrigerant of high-high boiling point component in saturated liquid state in the gas-liquid separator.

[0011] The mixed refrigerant of high-low boiling point component in saturated gaseous state is cooled into mixed refrigerant in saturated liquid state through the second condenser, throttled into gaseous-liquid two-phase flow state through the throttling valve, and evaporated into the mixed refrigerant of high-low boiling point component in saturated gaseous state after entering the first evaporator.

[0012] The mixed refrigerant of high-high boiling point component in saturated liquid state enters the main flow inlet of the ejector, is expanded into two-phase state through the nozzle of the ejector, injects the mixed refrigerant of high-low boiling point component in saturated gaseous state from the first evaporator, is depressurized into mixed gaseous refrigerant, is mixed into two-phase state in the ejector, is pressurized into high-pressure gaseous-liquid two-phase state refrigerant through the diffuser of the ejector, flows into the second evaporator, and is finally in the saturated state of the mixed refrigerant, and enters the compressor to realize a complete heat pump refrigerant cycle.

[0013] Further, the system further comprises a hot water outlet end and a hot water inlet end.

[0014] The domestic hot water enters the second condenser from the hot water inlet end, and is countercurrently heat-exchanged with the mixed refrigerant of high-low boiling point component in saturated gaseous state in the second condenser, is preheated, enters the first condenser, is countercurrently heat-exchanged with the high-temperature and high-pressure non-azeotropic mixed refrigerant in the first condenser, is heated to the required temperature, and is discharged from the hot water outlet end.

[0015] Further, the system further comprises a sewage outlet end and a sewage inlet end; the sewage enters the second evaporator from the sewage inlet end, is countercurrently heat-exchanged with the mixed gaseous-liquid two-phase state refrigerant in the second evaporator, enters the first evaporator, is countercurrently heat-exchanged with the mixed gaseous-liquid two-phase state refrigerant of high-low boiling point component in the first evaporator, and is discharged from the sewage outlet end.

[0016] Further, the non-azeotropic mixed refrigerant flows through the pipeline in the ejector-compression sewage source heat pump system; the non-azeotropic mixed refrigerant is a non-azeotropic refrigerant with a glide temperature greater than 10 DEG C.

[0017] Further, the non-azeotropic mixed refrigerant is any one of carbon dioxide / 2,3,3,3-tetrafluoropropene, carbon dioxide / trans-1,3,3,3-tetrafluoropropene and carbon dioxide / 1-chloro-3,3,3-trifluoropropene.

[0018] Further, in the carbon dioxide / 2,3,3,3-tetrafluoropropene non-azeotropic mixed refrigerant, the mass concentration of carbon dioxide is 40% to 80%, and the mass concentration of 2,3,3,3-tetrafluoropropene is 60% to 20%; the sum of the mass concentrations of carbon dioxide and 2,3,3,3-tetrafluoropropene is 100%.

[0019] Further, in the carbon dioxide / trans-1,3,3,3-tetrafluoropropene non-azeotropic mixed refrigerant, the mass concentration of carbon dioxide is 45% to 75%, and the mass concentration of trans-1,3,3,3-tetrafluoropropene is 55% to 25%; the sum of the mass concentrations of carbon dioxide and trans-1,3,3,3-tetrafluoropropene is 100%.

[0020] Further, in the carbon dioxide / 1-chloro-3,3,3-trifluoropropene non-azeotropic mixed refrigerant, the mass concentration of carbon dioxide is 55% to 80%, and the mass concentration of 1-chloro-3,3,3-trifluoropropene is 45% to 20%; the sum of the mass concentrations of carbon dioxide and 1-chloro-3,3,3-trifluoropropene is 100%.

[0021] Beneficial effects: compared with the prior art, the present application has the following advantages:

[0022] 1. The non-azeotropic mixed refrigerant can reduce the heat transfer temperature difference. The non-azeotropic mixed refrigerant has the temperature glide characteristic in the phase change process, and the phase change heat transfer temperature difference is reduced. The present application adjusts the component concentration, and the saturated liquid refrigerant of the mixed refrigerant with high-boiling-point components is introduced into the ejector as the working fluid. The saturated liquid refrigerant of the mixed refrigerant with high-boiling-point components is expanded into a two-phase state through the nozzle of the ejector, and injects the saturated gaseous refrigerant of the mixed refrigerant with high-low boiling-point components from the first evaporator. The mixed refrigerant in the first evaporator is the saturated gaseous refrigerant with high-low boiling-point components, so that the evaporation pressure is increased at the same evaporation temperature, the ejector back pressure is increased, the suction pressure of the compressor is increased, the suction and discharge pressure ratio is reduced, the power consumption of the compressor is reduced, and the system energy efficiency is improved.

[0023] 2、The present application adopts double evaporators and double condensers and an ejector system, introduces non-azeotropic mixed working medium with large difference in boiling point into the ejector-compression heat pump cycle, realizes two-stage condensation of the mixed refrigerant, reduces the pressure ratio of the new cycle, reduces the power consumption of the compressor, and realizes lower evaporation temperature and higher cycle efficiency in the ejector-compression heat pump cycle.

[0024] By changing the first condenser outlet dryness, adjusting the composition of the working fluid and the injection fluid, improving the temperature matching of the working medium in the heat exchanger, and thus improving the performance of the system.

[0025] 3、The present application realizes variable component concentration regulation through two-stage condensation of the first condenser, the second condenser and the gas-liquid separator; the saturated gaseous refrigerant of high and low boiling point working medium components is condensed by the second condenser and then enters the first evaporator for evaporation, so as to adjust the component concentration in the first evaporator, so that the evaporation pressure is increased at the same evaporation temperature. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the ejector-compression sewage source heat pump cycle system of the present application;

[0027] Figure 2 is the lgP-h pressure-enthalpy diagram of the working process of the ejector-compression sewage source heat pump cycle system shown in the present application.

[0028] Figure 1 , wherein: the compressor 1, the first condenser 2, the gas-liquid separator 3, the second condenser 4, the throttling valve 5, the first evaporator 6, the ejector 7, the second evaporator 8, the hot water outlet end 9, the hot water inlet end 10, the sewage outlet end 11, the sewage inlet end 12;

[0029] Figure 2 , wherein each point corresponds to: the second evaporator first outlet end 1a point, the compressor outlet end 2a point, the first condenser first outlet end 2' point, the gas-liquid separator first outlet end 2g point, the gas-liquid separator second outlet end 2l point, the mixed working medium two-phase state refrigerant 2l' point of high boiling point working medium components after expansion in the nozzle of the ejector, the second condenser first outlet end 3a point, the throttling valve outlet end 4a point, the first evaporator first outlet end 5a point, the mixed working medium gaseous refrigerant 5' point of high and low boiling point working medium components after pressure reduction in the ejector, the 6' point of the mixed working fluid and injection fluid, the ejector outlet end 6a point. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be further described below in combination with examples and the drawings of the specification.

[0031] As Figure 1As shown, the ejector-compression sewage source heat pump system based on the large glide temperature non-azeotropic working medium of the application comprises a compressor 1, a first condenser 2, a gas-liquid separator 3, a second condenser 4, a throttling valve 5, a first evaporator 6, an ejector 7, a second evaporator 8, a hot water outlet end 9, a hot water inlet end 10, a sewage outlet end 11, a sewage inlet end 12, and a non-azeotropic working medium flowing in the ejector-compression sewage source heat pump system through pipelines. The outlet end of the compressor 1 is connected with the first inlet end of the first condenser 2, the first outlet end of the first condenser 2 is connected with the inlet end of the gas-liquid separator 3, the first inlet end of the gas-liquid separator 3 is connected with the first inlet end of the ejector 7, the first outlet end of the first evaporator 6 is connected with the second inlet end of the ejector 7, the outlet end of the ejector 7 is connected with the first inlet end of the second evaporator 8, the first outlet end of the second evaporator 8 is connected with the inlet end of the compressor, the sewage inlet end 12 is connected with the second inlet end of the second evaporator 8, the second outlet end of the second evaporator 8 is connected with the second inlet end of the first evaporator 6, the second outlet end of the first evaporator 6 is connected with the sewage outlet end 11, the hot water inlet end 10 is connected with the second inlet end of the second condenser 4, the second outlet end of the second condenser 4 is connected with the second inlet end of the first condenser 2, and the second outlet end of the first condenser 2 is connected with the hot water outlet end 9.

[0032] In the application, the refrigerant used is a non-azeotropic refrigerant with a large glide temperature. The large glide temperature refers to a glide temperature greater than or equal to 10℃ during the evaporation process of the refrigerant.

[0033] The non-azeotropic working medium is any one of CO2 / R1234yf, CO2 / R1234ze(E), and CO2 / R1233zd.

[0034] CO2 / R1234yf, i.e. carbon dioxide (CO2) / 2,3,3,3-tetrafluoropropene (R1234yf);

[0035] CO2 / R1234ze(E), i.e. carbon dioxide (CO2) / trans-1,3,3,3-tetrafluoropropene (R1234ze(E));

[0036] CO2 / R1233zd, i.e. carbon dioxide (CO2) / 1-chloro-3,3,3-trifluoropropene (R1233zd).

[0037] In the carbon dioxide and 2,3,3,3-tetrafluoropropene mixed working medium, the mass concentration of carbon dioxide is 40% to 80%, the mass concentration of 2,3,3,3-tetrafluoropropene is 60% to 20%, and the sum of the mass concentrations is 100%; in the carbon dioxide and trans-1,3,3,3-tetrafluoropropene mixed working medium, the mass concentration of carbon dioxide is 45% to 75%, the mass concentration of trans-1,3,3,3-tetrafluoropropene is 55% to 25%, and the sum of the mass concentrations is 100%; in the carbon dioxide and 1-chloro-3,3,3-trifluoropropene mixed working medium, the mass concentration of carbon dioxide is 55% to 80%, the mass concentration of 1-chloro-3,3,3-trifluoropropene is 45% to 20%, and the sum of the mass concentrations is 100%.

[0038] Figure 2 The lgP-h pressure-enthalpy diagram of the sewage source heat pump cycle system working process shown in the present application.

[0039] The specific working process of the present application is: the compressor 1 inhales the saturated state of the mixed working medium, such as point 1a in the figure, Figure 2 After compression, it becomes a high-temperature and high-pressure azeotropic mixture, such as point 2a in the figure, Figure 2 After cooling by the first condenser 2, it becomes a gas-liquid mixed two-phase state refrigerant, such as point 2' in the figure, Figure 2 It flows into the gas-liquid separator 3, and is divided into two paths in the gas-liquid separator 3.

[0040] One path: the saturated gas state refrigerant of the high-low boiling point working medium component, such as point 2g in the figure, Figure 2 After cooling by the second condenser 4, it becomes a mixed working medium saturated liquid refrigerant, such as point 3a in the figure, Figure 2 After throttling by the throttle valve 5, it becomes a gas-liquid two-phase flow state, such as point 4a in the figure, Figure 2 After evaporation in the first evaporator 6, it becomes a mixed working medium saturated gas state refrigerant, such as point 5a in the figure. Figure 2

[0041] The other path: the mixed working medium saturated liquid refrigerant of the high-high boiling point working medium component, such as point 2l in the figure, Figure 2 It enters the main flow inlet of the ejector 7, and is expanded to a two-phase state by the nozzle of the ejector 7, such as point 2l' in the figure, Figure 2 It injects the mixed working medium gaseous refrigerant of the high-low boiling point working medium component from the first evaporator 6, such as point 5a in the figure, Figure 2 After pressure reduction, it becomes a mixed working medium gaseous refrigerant, such as point 5' in the figure, Figure 2 The two fluids are mixed in the ejector 7 to become a two-phase state, such as point 6' in the figure, Figure 2 After pressure expansion in the pressure expansion section of the ejector 7, it becomes a gas-liquid two-phase state with higher pressure, such as point 6a in the figure, Figure 2 After flowing into the second evaporator 8, it becomes a saturated mixed working medium, such as point 7a in the figure. Figure 2 ​Point 1a; enters the compressor 1, and realizes complete heat pump refrigerant cycle.

[0042] Wherein, the sewage enters the second evaporator 8 from the sewage inlet end 12, and is countercurrently heat-exchanged with the mixed gas-liquid two-phase state refrigerant, and then Figure 2 Point 6a; enters the first evaporator 6, and is countercurrently heat-exchanged with the mixed gas-liquid two-phase state refrigerant of the high-low boiling point working component, and then Figure 2 Point 4a; is discharged from the sewage outlet end 11;

[0043] The domestic hot water enters the second condenser 4 from the hot water inlet end 10, and is countercurrently heat-exchanged with the saturated gas state refrigerant of the high-low boiling point working component, and then Figure 2 Point 2g; is preheated, enters the first condenser 2, and is countercurrently heat-exchanged with the high-temperature high-pressure non-azeotropic mixed working component, and then Figure 2 Point 2a; is heated to the required temperature, and is discharged from the hot water outlet end 9.

[0044] In the above working method, the variable component concentration regulation is realized through the two-stage condensation of the first condenser 2, the second condenser 4 and the gas-liquid separator 3. The high-boiling point component in the non-azeotropic mixed working component is first condensed in the first condenser 2, and the gas-liquid separation of the non-azeotropic mixed working component is completed in the gas-liquid separator.

[0045] The high-low boiling point working component enters the second condenser 4, is condensed, is throttled by the throttle valve 5, and then enters the first evaporator 6 to evaporate. Compared with the single working component jet-compression type sewage source heat pump system, the mixed working component in the first evaporator 6 is the high-low boiling point working component, so that the evaporation pressure is increased at the same evaporation temperature, which further causes the pressure of the mixed working component saturated liquid refrigerant of the high-high boiling point working component entering the jet pump 7 to be increased, that is, the back pressure of the jet pump 7 is increased, the suction pressure of the compressor 1 is increased, the suction and discharge pressure ratio is reduced, and the power consumption of the compressor 1 is reduced, so that the energy efficiency of the jet-compression type sewage source heat pump system based on the large slip temperature non-azeotropic working component of the application is improved compared with the traditional jet-compression type sewage source heat pump system.

[0046] The application uses the non-azeotropic refrigerant with large slip temperature as the circulating working component, uses the large slip temperature characteristics of the non-azeotropic working component in the constant pressure phase change to reduce the heat transfer temperature difference, and increases the suction pressure of the compressor, reduces the suction and discharge pressure ratio of the compressor, and further improves the performance of the jet-compression type sewage source heat pump through the two-stage condensation and variable component concentration regulation.

[0047] The above only describes the preferred embodiments of the application, and the protection scope of the application is not limited to the above embodiments, but any equivalent modification or change made by the ordinary skilled in the art according to the disclosed content of the application shall be included in the protection scope recorded in the claims.

Claims

1. An ejector-compression sewage source heat pump system based on a large-slippage temperature non-azeotropic working medium, comprising an ejector (7) and a first evaporator (6) connected to the ejector (7), characterized in that: Separate the mixed refrigerant in two-phase state in the system into mixed refrigerant saturated liquid refrigerant of high-high boiling point working component and saturated liquid refrigerant of high-low boiling point working component; The mixed refrigerant saturated liquid refrigerant of high-high boiling point working component is introduced into the ejector (7); the saturated liquid refrigerant of high-low boiling point working component is introduced into the first evaporator (6) to generate mixed refrigerant saturated gaseous refrigerant of high-low boiling point working component through the first evaporator (6); The mixed refrigerant saturated liquid refrigerant of high-high boiling point working component is expanded into two-phase state through the nozzle of the ejector (7) to inject the mixed refrigerant saturated gaseous refrigerant of high-low boiling point working component from the first evaporator (6); The system comprises a compressor (1), a first condenser (2), a gas-liquid separator (3), a second condenser (4), a first evaporator (6), an ejector (7) and a second evaporator (8); The compressor (1) sucks mixed working substance in saturated state, and compresses the mixed working substance into high-temperature and high-pressure non-azeotropic mixed working substance, which is cooled into gaseous-liquid mixed two-phase state refrigerant through the first condenser (2), and flows into the gas-liquid separator (3), and is separated into saturated gaseous refrigerant of high-low boiling point working component and mixed refrigerant saturated liquid refrigerant of high-high boiling point working component in the gas-liquid separator (3); The saturated gaseous refrigerant of high-low boiling point working component is cooled into mixed refrigerant saturated liquid refrigerant through the second condenser (4), is throttled into gaseous-liquid two-phase flow state through the throttle valve (5), and enters the first evaporator (6) to become mixed refrigerant saturated gaseous refrigerant of high-low boiling point working component after evaporation; The mixed refrigerant saturated liquid refrigerant of high-high boiling point working component enters the main flow inlet of the ejector (7), is expanded into two-phase state through the nozzle of the ejector (7), injects the mixed refrigerant saturated gaseous refrigerant of high-low boiling point working component from the first evaporator (6), becomes mixed gaseous refrigerant after decompression, and is mixed into two-phase state in the ejector (7), is pressurized into mixed gaseous-liquid two-phase state refrigerant with higher pressure through the diffuser section of the ejector (7), flows into the second evaporator (8) to become mixed working substance in saturated state, and finally enters the compressor (1) to realize complete heat pump refrigerant circulation; The system further comprises a hot water outlet end (9) and a hot water inlet end (10); The domestic hot water enters the second condenser (4) from the hot water inlet end (10), and is countercurrently heat-exchanged with the saturated gaseous refrigerant of high-low boiling point working component in the second condenser (4), is preheated, enters the first condenser (2), is countercurrently heat-exchanged with the high-temperature and high-pressure non-azeotropic mixed working substance in the first condenser (2), is heated to the required temperature, and is discharged from the hot water outlet end (9); The sewage outlet end (11) and the sewage inlet end (12) are further included; the sewage enters the second evaporator (8) from the sewage inlet end (12), and after countercurrent heat exchange with the mixed gas-liquid two-phase state refrigerant in the second evaporator (8), enters the first evaporator (6), and after countercurrent heat exchange with the mixed gas-liquid two-phase state refrigerant of the high-low boiling point working medium component in the first evaporator (6), is discharged from the sewage outlet end (11); The non-azeotropic working medium flows in the ejector-compression sewage source heat pump system through a pipeline; the non-azeotropic working medium is a non-azeotropic refrigerant working medium with a glide temperature greater than 10 DEG C.

2. The ejector-compression sewage source heat pump system based on the large- slip temperature non-azeotropic working fluid according to claim 1, characterized in that, The non-azeotropic working medium is any one of carbon dioxide / 2,3,3,3-tetrafluoropropene, carbon dioxide / trans-1,3,3,3-tetrafluoropropene, and carbon dioxide / 1-chloro-3,3,3-trifluoropropene.

3. The ejector-compression sewage source heat pump system based on the large glide temperature non-azeotropic refrigerant according to claim 2, characterized in that: In the carbon dioxide / 2,3,3,3-tetrafluoropropene non-azeotropic working medium, the mass concentration of carbon dioxide is 40% to 80%, and the mass concentration of 2,3,3,3-tetrafluoropropene is 60% to 20%; the sum of the mass concentrations of carbon dioxide and 2,3,3,3-tetrafluoropropene is 100%.

4. The ejector-compression sewage source heat pump system based on the large glide temperature non-azeotropic refrigerant according to claim 2, characterized in that: In the carbon dioxide / trans-1,3,3,3-tetrafluoropropene non-azeotropic working medium, the mass concentration of carbon dioxide is 45% to 75%, and the mass concentration of trans-1,3,3,3-tetrafluoropropene is 55% to 25%; the sum of the mass concentrations of carbon dioxide and trans-1,3,3,3-tetrafluoropropene is 100%.

5. The ejector-compression sewage source heat pump system based on the large glide temperature non-azeotropic refrigerant according to claim 2, characterized in that: In the carbon dioxide / 1-chloro-3,3,3-trifluoropropene non-azeotropic working medium, the mass concentration of carbon dioxide is 55% to 80%, and the mass concentration of 1-chloro-3,3,3-trifluoropropene is 45% to 20%; the sum of the mass concentrations of carbon dioxide and 1-chloro-3,3,3-trifluoropropene is 100%.

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