A compression-type high-temperature heat pump system with energy storage enthalpy compensation

Abstract

The application discloses a compression type high-temperature heat pump system with energy storage and enthalpy supplement, which comprises a compressor, a condenser, an ejector, a gas-liquid separator, an expansion valve, an evaporator, an intermediate heat exchanger and a heat accumulator. The system can realize two kinds of operation mode switching, namely supercooling energy storage mode and energy release and enthalpy supplement mode. Different working modes are switched according to system operation conditions and energy storage conditions of the heat accumulator. In the energy storage mode, the supercooling energy storage mode is switched, and the heat accumulator is stored by using the supercooling amount of working fluid at the condenser outlet. In the energy release mode, the energy release and enthalpy supplement mode is switched, the mass flow of the steam injection branch is increased by using the heat in the heat accumulator, and the heat supply capacity of the system and the operation performance of the system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of low-grade waste heat conversion, and in particular to a compression-type high-temperature heat pump system with energy storage and enthalpy supplement, which can realize expansion work recovery and system heating efficiency improvement through mode switching. By setting a heat accumulator and an ejector, the effective recovery of expansion work is realized, avoiding the large amount of irreversible thermodynamic energy loss generated in the traditional expansion valve. The heat pump system can realize supercooling energy storage and energy release enthalpy supplement through the on-off control of the three-way valve. Both modes can effectively utilize the thermal energy and pressure energy of the working fluid at the outlet of the condenser to realize the conversion of a large amount of low-grade waste heat. BACKGROUND

[0002] In industrial production processes, a large amount of primary energy is used in the form of fuel combustion to generate heat energy for industrial production process systems. However, the existing industrial production processes cannot completely convert the heat of combustion into the required energy, and most of the available heat is discharged into the environment in various forms, causing thermal pollution and energy waste. By recovering low-grade industrial waste heat, the energy utilization efficiency of the process production process can be effectively improved. Common waste heat utilization methods include heat work conversion, heat cold conversion, and heat grade conversion, among which heat work conversion is difficult to effectively convert into electrical energy when utilizing 150℃ low-grade waste heat, and the operating efficiency of heat cold conversion driven by low-grade waste heat is not high. Therefore, using heat pump technology to improve the heat grade of low-temperature waste heat is an effective method for efficient utilization of a large amount of industrial waste heat. By converting or upgrading the heat energy that would otherwise be wasted, the energy efficiency of the industrial process is improved. Compression-type heat pumps can be used to improve lower-temperature industrial waste heat, requiring the consumption of part of the electrical energy to achieve the grade improvement of a large amount of waste heat. In order to minimize the consumption of high-grade electrical energy, further research is needed on the layout of high-performance heat pump systems.

[0003] At lower waste heat temperatures, the traditional single-stage compression system has the disadvantages of high compression ratio, high discharge temperature, and large compression power. Therefore, based on the single-stage compression system, many scholars have proposed many improved systems including quasi-two-stage compression heat pump system, multi-stage compression heat pump system, and cascade heat pump system. The optimization idea of these systems is to reduce the compression ratio of the single compressor as much as possible and make the compression process approach isothermal compression. Among them, the air-supplying and enthalpy-increasing system uses only one compressor to realize the reduction of discharge temperature and compression power consumption, and has lower investment cost. In addition, the air supply of the compressor can increase the flow rate of the working fluid of the system to a certain extent, while increasing the heating capacity of the system; the adjustability of the air supply mass flow rate increases the flexibility of the compressor control, making the system adjustment more convenient.

[0004] Compared with the ideal reverse Carnot cycle, the use of expansion valves as expansion devices in conventional vapor compression heat pumps results in a large amount of irreversible thermodynamic energy loss. Ordinary quasi-two-stage compression systems usually use flash tanks or subcoolers as key equipment to achieve air supplement and enthalpy increase, but the air supplement mass flow generated by this method is quite limited. Therefore, some scholars use waste gas with a higher temperature than the side heat of the evaporator to increase the mass flow of compressor air supplement, which can significantly enhance system performance. The thermodynamic principle of this performance enhancement method is to improve the average temperature of the system. However, in practical applications, it is often difficult to meet the requirements of different temperature extra-heat inputs. Therefore, how to significantly reduce high-grade compression work and improve the system's thermal grade conversion efficiency under the condition of a single extra-heat source is an important problem to be solved.

[0005] Chinese invention patent CN118408296A discloses a heat pump cycle system with intermediate air injection ejector and its control method. This technical solution uses a solar collector to collect solar heat, increases the mass flow of air supplement and enthalpy increase branch, so that more working medium avoids the process of expansion and compression, and the system performance is effectively improved. In the process of industrial waste heat recovery, there is not necessarily two temperature waste heat sources in the actual process, and the operation scene of double-temperature waste heat source limits the application of the system.

[0006] Chinese invention patent CN109931721A discloses a solar heat storage defrosting air supplement and enthalpy increase heat pump system. The system has two operating modes, namely heat storage mode and defrosting mode. In the heat storage mode, the solar sub-cycle and the heat energy of the working fluid at the outlet of the condenser are used to store solar heat and supercooling heat energy in the heat accumulator. In the defrosting mode, the heat in the heat accumulator is used for defrosting to ensure the normal heating of the system. The system realizes heat storage and defrosting in low-temperature scenarios, but its double-temperature waste heat source operation scene also limits the application of the system. SUMMARY

[0007] The application introduces a regenerator into a jet-compression heat pump system, and designs a compression high-temperature heat pump system with energy storage and enthalpy supplement through reasonable heat storage and heat release modes. The system can effectively utilize the heat energy and pressure energy of the working fluid at the outlet of the condenser, and reduce the irreversible thermodynamic energy loss existing in the expansion process of the traditional heat pump cycle. The system can operate in two modes, namely supercooling energy storage mode and energy release and enthalpy supplement mode. In the supercooling energy storage mode, the system stores the supercooling heat released by the working fluid. The supercooled working fluid enters the evaporator through the gas-liquid separator to absorb heat, thereby increasing the heating capacity of the system. In the energy release and enthalpy supplement mode, the working fluid at the outlet of the condenser releases heat in the intermediate heat exchanger, and then absorbs the heat of the regenerator to become enthalpy supplement steam after being depressurized by the expansion valve. In this mode, the exhaust temperature of the compressor of the system is reduced, the compression power consumption is reduced, and the system has excellent heating performance. The system can effectively solve the problem that too much high-grade electric energy is consumed in the compression heat pump in the process of upgrading the low-temperature industrial waste heat. In the process of upgrading the low-temperature industrial waste heat, the system has high economic effect and environmental friendliness.

[0008] In order to achieve the object of the application, the application provides a compression high-temperature heat pump system with energy storage and enthalpy supplement, which comprises a compressor, a condenser, a three-way valve, an expansion valve, an ejector, a gas-liquid separator, an evaporator, a regenerator and an intermediate heat exchanger. The system is switched between the supercooling energy storage mode and the energy release and enthalpy supplement mode through the three-way valve. The three-way valve comprises a first three-way valve and a second three-way valve. The expansion valve comprises a first expansion valve, a second expansion valve and a third expansion valve.

[0009] In the supercooling energy storage mode, the outlet of the compressor is connected with the inlet of the condenser, the outlet of the condenser is connected with the inlet of the first three-way valve, one of the outlets of the first three-way valve is connected with the ejector, and the other outlet is connected with the regenerator. The outlet of the regenerator is connected with the inlet of the first expansion valve, the outlet of the first expansion valve is connected with the inlet of the gas-liquid separator, the outlet of the ejector is connected with the gas-liquid separator, the gas phase outlet of the gas-liquid separator is connected with the intermediate heat exchanger, the outlet of the intermediate heat exchanger is connected with the inlet of the compressor, the liquid phase outlet of the gas-liquid separator is connected with the second expansion valve, the outlet of the second expansion valve is connected with the evaporator, and the outlet of the evaporator is connected with the secondary nozzle inlet of the ejector. The working fluid at the outlet of the evaporator is injected into the injection chamber of the ejector by the fluid in the working nozzle of the ejector.

[0010] In the energy-releasing and enthalpy-supplementing mode, the outlet of the compressor is connected with the inlet of the condenser, the outlet of the condenser is connected with the inlet of the first three-way valve, one of the outlets of the first three-way valve is connected with the ejector, the other outlet of the first three-way valve is connected with the second three-way valve, the intermediate heat exchanger, the third expansion valve and the accumulator in sequence, the accumulator is connected with the air supplementing port of the compressor; the outlet of the ejector is connected with the gas-liquid separator, the gas phase outlet of the gas-liquid separator is connected with the inlet of the intermediate heat exchanger, the outlet of the intermediate heat exchanger is connected with the compressor, the working fluid is heated in the intermediate heat exchanger and then enters the compressor, the liquid phase outlet of the gas-liquid separator, the second expansion valve, the evaporator and the ejector are connected in sequence, the working fluid is depressurized by the second expansion valve and then enters the evaporator, and the working fluid at the outlet of the evaporator is injected into the injection chamber of the ejector by the fluid in the working injection pipe of the ejector.

[0011] Further, the ejector can use the high-pressure fluid at the outlet of the condenser to inject the low-pressure fluid at the outlet of the evaporator, so as to increase the pressure of the fluid at the inlet of the compressor, and thus reduce the compression ratio of the compressor.

[0012] Further, the ejector is an area-adjustable ejector, which can adjust the throat area of the ejector according to the actual operating condition of the system.

[0013] The three-way valve is an adjustable three-way valve, which can realize free opening and closing of the valve.

[0014] Further, when the system is switched to the energy-releasing and enthalpy-supplementing mode, the fluid at the outlet of the accumulator is used as the intermediate air supplementing of the compressor; when the system is switched to the supercooling energy storage mode, part of the working fluid at the outlet of the condenser is supercooled in the accumulator, and the released heat is stored in the accumulator.

[0015] Further, the compressor is an air-supplementing compressor.

[0016] Further, when the system is in the energy-releasing and enthalpy-supplementing mode, the air supplementing channel of the compressor is opened, and the working fluid at the outlet of the accumulator serves as the intermediate air supplementing of the compressor; when the system is in the supercooling energy storage mode, the air supplementing port of the compressor is closed, and the supercooling heat of the fluid at the outlet of the condenser is stored in the accumulator.

[0017] Further, in the supercooling energy storage mode, the outlet pressure of the ejector is the same as the pressure of the working fluid at the branch where the accumulator is located after being depressurized by expansion.

[0018] Further, in the energy-releasing and enthalpy-supplementing mode, the outlet temperature of the accumulator is higher than the outlet temperature of the intermediate heat exchanger, but lower than the condensing temperature.

[0019] Further, in the supercooling energy storage mode, the working fluid is compressed by the compressor and enters the condenser to release heat and condense. The condensed working fluid is divided into two streams by the first three-way valve. One stream enters the primary nozzle of the ejector to complete the pressure reduction and speed increase, and then injects the outlet fluid of the evaporator into the mixing chamber of the ejector, and the mixed fluid enters the gas-liquid separator after being pressurized by the ejector. The other stream enters the regenerator to release heat, and the released heat is stored in the regenerator. The working fluid in the regenerator is pressurized by the first expansion valve, and then enters the gas-liquid separator to mix with the outlet fluid of the ejector. The gaseous fluid in the gas-liquid separator enters the intermediate heat exchanger to absorb heat and become superheated steam, and then enters the compressor to complete the compression process. The liquid phase fluid enters the second expansion valve to expand and reduce pressure, and then enters the evaporator to absorb heat and evaporate, and finally is injected into the ejector by the primary stream of the ejector.

[0020] Further, in the energy release and enthalpy supplement mode, the working fluid is compressed by the compressor and mixed with the outlet fluid of the regenerator. The mixed working fluid is compressed in the high-pressure chamber of the compressor, and then enters the condenser to release heat and condense. The condensed working fluid is divided into two streams by the first three-way valve. One stream becomes the injection fluid of the ejector, enters the ejector to reduce pressure and increase speed, and then injects the outlet fluid of the evaporator into the mixing chamber of the ejector. The mixed fluid enters the gas-liquid separator after being pressurized by the ejector. The other stream enters the intermediate heat exchanger to release heat, and then enters the third expansion valve to expand and reduce pressure. The reduced pressure working fluid absorbs heat from the regenerator and then enters the compressor to complete the air supplement. The gaseous working fluid in the gas-liquid separator enters the intermediate heat exchanger to absorb heat and become superheated steam, and then enters the compressor to complete the compression process. The liquid working fluid in the gas-liquid separator enters the second expansion valve to expand and reduce pressure, and then enters the evaporator to absorb heat and evaporate. The outlet fluid of the evaporator is injected into the ejector by the working fluid in the ejector.

[0021] In the supercooling energy storage mode, the regenerator can store the supercooling heat of the outlet working fluid of the condenser. The working fluid at a certain temperature is reduced in pressure by the expansion valve and enters the gas-liquid separator. In the supercooling energy storage mode, the energy stored in the regenerator is part of the expansion work that would otherwise be dissipated.

[0022] In the energy release and enthalpy supplement mode, the intermediate heat exchanger and the enthalpy supplement compressor recover the expansion work in the energy release and enthalpy supplement mode, and the regenerator increases the mass flow of the air supplement using the expansion work recovered in the supercooling energy storage mode, thereby improving the overall performance of the system.

[0023] The compressor can compress the working fluid, increase the temperature and pressure thereof, different types and capacities of the compressor can be selected according to the characteristics of the working fluid and the operation condition of the system; the condenser can realize heat exchange of the working fluid to a high-temperature carrier, different sizes and types of the condenser can be selected according to the heat release temperature and the heat release amount; the three-way valve can realize flow path switching of the working fluid, different sizes and types of the three-way valve can be selected according to different control requirements of the system and the flow of the working fluid; the ejector can use the induced fluid to increase the pressure of the induced fluid, realize the pressure boosting effect of the induced fluid, different specifications of the adjustable ejector can be selected according to the thermodynamic characteristics of the induced fluid and the induced fluid; the gas-liquid separator can separate working fluids of different phases and has the function of liquid storage, different types of separation devices can be replaced according to actual application requirements; the expansion valve can realize pressure reduction of the working fluid in the system, different types of expansion devices can be replaced according to the mass flow of the working fluid and different application scenarios; the evaporator can absorb heat exchange between the working fluid and the outside, input heat to the system, different types and sizes of the evaporator can be selected according to the actual heat absorption amount and the use scenario; the heat accumulator can store the heat released by the working fluid in the heat storage medium, different sizes and types of the heat accumulator can be selected according to the difference of the heating capacity of the system; the intermediate heat exchanger allows two different fluids to exchange heat inside, different sizes and types of the heat exchanger can be selected according to the flow characteristics and flow of the heat exchange fluid.

[0024] Compared with the existing quasi-two-stage compression heat pump system, the present application has the following advantages:

[0025] The system can realize mode switching, energy storage, supplementing enthalpy and efficiency improvement, and the expansion work recovered in the supercooling energy storage mode can be used to increase the supplement air quantity in the energy release and enthalpy supplement mode. In addition, the heat energy and pressure energy of the working fluid at the outlet of the condenser in the energy release and enthalpy supplement mode can be utilized through the intermediate heat exchanger and the supplement enthalpy compressor. Compared with the traditional quasi-two-stage compression heat pump, the presence of the heat accumulator enhances the overall operation performance of the system. Under the condition of a single waste heat source, the performance enhancement effect of increasing the average heat absorption temperature of the double waste heat source is realized.

[0026] The system utilizes the self-heat storage characteristic, uses the waste heat source as the low-temperature heat source, and has a unique advantage in the high-temperature heat pump. For the energy storage and enthalpy supplement mode, sufficient waste heat can be stored through the heat accumulator, avoiding waste of the waste heat; for the energy release mode, the system has good operation performance, i.e., a higher COP. The utilization level of the waste heat by the system can be improved.

[0027] The system described in this invention can fully utilize the thermal and pressure energy of the condenser outlet fluid through mode switching. Switching between different operating modes at different operating stages improves the waste heat conversion efficiency of the heat pump system. Compared with traditional quasi-two-stage compression heat pumps, the system described in this invention features a reasonable system layout, flexible operating modes, significant energy savings, and stable heating.

[0028] This invention utilizes the heat from the condenser outlet to enhance the system's enthalpy compensation performance through a self-reinforcing mechanism. Compared to existing solutions, the system proposed in this invention has a wider range of applications and is not limited by the number of waste heat sources in the actual scenario. Simultaneously, it improves system performance without increasing system complexity.

[0029] Using an ejector as an expansion device in a heat pump system can reduce expansion work loss and improve system heating efficiency. As a static component, the ejector is simple in structure, low in cost, and reliable. The recovered expansion work can be used to increase the pressure of the fluid at the compressor inlet, reducing compressor power consumption. Using an ejector in a quasi-two-stage compression heat pump system can minimize the consumption of high-grade compression work. This combined approach has significant advantages in improving the quality of low-temperature waste heat.

[0030] This invention utilizes a heat accumulator to recover heat from the condenser outlet and an ejector to recover part of the expansion work of the working fluid, further improving performance. Furthermore, in the field of industrial heat recovery, this invention effectively overcomes the problem of excessively high compressor discharge temperature and compressor overheating by utilizing heat storage and gas replenishment enthalpy enhancement technology.

[0031] The system of this invention has a simpler system structure than existing systems, avoids pressure fluctuations caused by switching three-way valves, and improves system stability. Attached Figure Description

[0032] Appendix Figure 1 This is a schematic diagram of a compression-type high-temperature heat pump system with energy storage and enthalpy replenishment according to an embodiment of the present invention.

[0033] Appendix Figure 2 This is a schematic diagram of the subcooled energy storage mode of a compression-type high-temperature heat pump system with energy storage enthalpy compensation according to an embodiment of the present invention.

[0034] Appendix Figure 3 This is a schematic diagram of the energy release and enthalpy replenishment mode of a compression-type high-temperature heat pump system with energy storage and enthalpy replenishment according to an embodiment of the present invention. Detailed Implementation

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] Please see Figure 1The application provides a compression type high-temperature heat pump system with energy storage and enthalpy supplement, which comprises nine components, i.e., a compressor 1, a condenser 2, a three-way valve, an ejector 4, a gas-liquid separator 5, an expansion valve, an evaporator 7, a heat accumulator 9 and an intermediate heat exchanger 11, and the components work cooperatively. Two operation modes, i.e., a supercooling energy storage mode and an energy release and enthalpy supplement mode, can be realized by controlling the flow path switching of the three-way valve. The system can be switched to the corresponding mode according to the operation stage.

[0037] In some embodiments of the application, the compressor 1 can compress the working fluid to increase the temperature and pressure of the working fluid, wherein different types and capacities of compressors can be selected according to the characteristics of the working fluid and the operation condition of the system; the condenser 2 can realize heat exchange between the working fluid and a high-temperature carrier, and different sizes and types of condensers can be selected according to the heat release temperature and heat release amount; the three-way valve is used for realizing flow path switching of the working fluid, and different sizes and types of three-way valves can be selected according to different control requirements of the system and the flow of the working fluid, the three-way valve comprises a first three-way valve 3 and a second three-way valve 8; the ejector 4 can use a motive fluid to increase the pressure of the induced fluid to realize the pressure increasing effect of the induced fluid, and different specifications of adjustable ejectors can be selected according to the thermodynamic characteristics of the motive fluid and the induced fluid; the gas-liquid separator 5 can separate working fluids in different phases and has the function of liquid storage, and different types of separation devices can be replaced according to actual application requirements; the expansion valve can realize pressure reduction of the working fluid in the system, and different types of expansion devices can be replaced according to the mass flow of the working fluid and different application scenarios, the expansion valve comprises a first expansion valve 10, a second expansion valve 6 and a third expansion valve 12; the evaporator 7 can absorb heat exchange between the working fluid and the outside to input heat into the system, and different types and sizes of evaporators can be selected according to the actual heat absorption amount and the use scenario; the heat accumulator 9 can store the heat released by the working fluid in the heat storage medium, and different sizes and types of heat accumulators can be selected according to the difference in heating capacity of the system; the intermediate heat exchanger 11 allows two different fluids to exchange heat inside, and different sizes and types of heat exchangers can be selected according to the flow characteristics and flow of the heat exchange fluids.

[0038] The three-way valve is an adjustable three-way valve, which can realize free opening and closing of the valve.

[0039] In some embodiments of the application, the ejector 14 is an area-adjustable ejector, which can adjust the throat area of the ejector 14 according to the actual operation condition of the system to improve the injection capacity of the ejector 14. The ejector 14 can adapt to different operation conditions.

[0040] In some embodiments of the application, the ejector 14 is a two-phase ejector, which is a typical expansion work recovery equipment and has the characteristics of simple structure and low cost.

[0041] In some embodiments of the present application, the gas-liquid separator 5 has 2 inlets and 2 outlets, and the working fluid can be mixed at the same pressure inside.

[0042] Figure 2 A schematic diagram of the subcooling energy storage mode of the compression high-temperature heat pump system with energy storage and enthalpy compensation is provided in the present application. In the subcooling energy storage stage, the outlet of the compressor 1 is connected to the inlet of the condenser 2. The outlet fluid of the condenser 2 is divided into two paths after passing through the first three-way valve 3. One path enters the working nozzle of the ejector 4 to complete the pressure reduction and speed increase, and then introduces the fluid at the outlet of the evaporator 7 into the ejector 4. The two fluids are mixed in the mixing chamber of the ejector 4. The other path enters the heat accumulator 9 through the second three-way valve 8 to complete the subcooling and heat release. The outlet of the heat accumulator 9 is connected to the inlet of the first expansion valve 10. The outlet of the first expansion valve 10 is connected to one of the inlets of the gas-liquid separator 5. The outlet of the ejector 4 is connected to the other inlet of the gas-liquid separator 5. The gas phase outlet of the gas-liquid separator 5 is connected to the intermediate heat exchanger 11. The outlet of the intermediate heat exchanger 11 is connected to the inlet of the compressor 1. The liquid phase outlet of the gas-liquid separator 5 is connected to the second expansion valve 6. The second expansion valve 6 is connected to the evaporator 7. The working fluid is introduced into the evaporator 7 after passing through the second expansion valve 6. The outlet of the evaporator 7 is connected to the secondary nozzle inlet of the ejector 4. The working fluid at the outlet of the evaporator 7 is introduced into the injection chamber of the ejector 4 by the fluid in the working nozzle of the ejector 4.

[0043] In the subcooling energy storage stage of the heat accumulator, the working fluid is pressurized by the compressor 1 and then introduced into the condenser 2 to release heat and condense. The condensed working fluid in the condenser 2 is divided into two paths after passing through the first three-way valve 3. One path enters the working nozzle (primary nozzle) of the ejector 4 to complete the pressure reduction and speed increase, and then introduces the fluid at the outlet of the evaporator 7 into the ejector 4. The two fluids are mixed in the mixing chamber of the ejector 4. The mixed fluid is pressurized by the diffuser section of the ejector 4 and then enters the gas-liquid separator 5. The other path enters the heat accumulator 9 to complete the subcooling and heat release. The released heat is stored in the heat accumulator 9. The working fluid after the subcooling and heat release in the heat accumulator 9 is expanded by the first expansion valve 10. The expanded working fluid enters the gas-liquid separator 5 and is mixed with the outlet fluid of the ejector 4. The gas phase fluid in the gas-liquid separator 5 is heated in the intermediate heat exchanger 11 to become superheated steam. The superheated steam enters the compressor 1 to complete the compression process. The liquid phase fluid enters the second expansion valve 6 to be expanded and then enters the evaporator 7 to be heated and evaporated. Finally, the working fluid is introduced into the injection chamber of the ejector 4 by the primary flow in the working nozzle of the ejector 4.

[0044] The heat accumulator 9 can store the subcooling heat of the working fluid at the outlet of the condenser 2. The working fluid at a certain temperature is depressurized by the first expansion valve 10 and then enters the gas-liquid separator 5. In the subcooling energy storage mode, the energy stored in the heat accumulator 9 is part of the expansion work that would have been dissipated.

[0045] The outlet pressure of the ejector 4 is the same as the pressure of the working fluid after the expansion and pressure reduction of the branch of the regenerator 9.

[0046] Figure 3 A schematic diagram of the energy release and enthalpy supplement mode of the compression high-temperature heat pump system with energy storage and enthalpy supplement is provided. In the energy release and enthalpy supplement stage of the regenerator, the outlet of the compressor 1 is connected to the inlet of the condenser 2. The working fluid after heat release in the condenser 2 enters the first three-way valve 3 and is divided into two streams. One stream becomes the injection fluid of the ejector 4, and the other stream enters the intermediate heat exchanger 11 and releases heat. The working fluid after heat release enters the third expansion valve 12 and is reduced in pressure. The outlet of the third expansion valve 12 is connected to the inlet of the regenerator 9, and the outlet of the regenerator 9 is connected to the air supplement port of the compressor 1. The working fluid absorbs the heat in the regenerator 9 and enters the air supplement port of the compressor 1. The outlet of the ejector 4 is connected to the gas-liquid separator 5, and the gas phase outlet of the gas-liquid separator 5 is connected to the inlet of the intermediate heat exchanger 11. The working fluid absorbs heat in the intermediate heat exchanger 11 and enters the compressor 1. The liquid phase outlet of the gas-liquid separator 5 is connected to the inlet of the second expansion valve 6, and the outlet of the second expansion valve 6 is connected to the evaporator 7. The working fluid after pressure reduction by the second expansion valve 6 enters the evaporator 7. The outlet of the evaporator 7 is connected to the secondary nozzle of the ejector 4.

[0047] In the energy release and enthalpy supplement stage of the regenerator, the working fluid after pressure reduction by the compressor 1 is mixed with the outlet fluid of the regenerator 9 in the high-pressure chamber of the compressor 1. The mixed working fluid is compressed and raised in pressure in the high-pressure chamber of the compressor 1. The working fluid after pressure rise enters the condenser 2 and releases heat. The working fluid after heat release enters the first three-way valve 3 and is divided into two streams. One stream becomes the injection fluid of the ejector 4, and the injection fluid enters the working nozzle of the ejector 4 and is reduced in pressure and increased in speed. The working fluid after speed increase injects the working fluid from the outlet of the evaporator 7 in the mixing chamber of the ejector 4. The mixed fluid enters the diffuser section of the ejector 4 and is raised in pressure. The working fluid after pressure rise enters the gas-liquid separator 5. The other stream enters the intermediate heat exchanger 11 and releases heat. The working fluid after heat release enters the third expansion valve 12 and is expanded and reduced in pressure. The working fluid after pressure reduction absorbs heat in the regenerator 9 and enters the compressor 1 to complete air supplement, effectively reducing the outlet temperature of the fluid in the compressor 1. The gaseous working medium in the gas-liquid separator 5 enters the intermediate heat exchanger 11 and absorbs heat to become superheated steam, and then enters the compressor 1 and is compressed and raised in pressure. The liquid working medium enters the second expansion valve 6 and is expanded and reduced in pressure. The working fluid after pressure reduction enters the evaporator 7 and absorbs heat to evaporate. The outlet fluid of the evaporator 7 is injected by the working fluid in the working nozzle of the ejector 4 and enters the injection chamber of the ejector 4.

[0048] In some embodiments of the present application, the heat storage medium in the heat accumulator 9 is a phase change material. In the energy recovery and enthalpy supplement mode, the outlet temperature of the heat accumulator 9 (the enthalpy supplement temperature / pressure) is higher than the inlet temperature of the compressor 1 (the temperature of the superheated steam in the intermediate heat exchanger 11), but lower than the condensing temperature (the condensing pressure).

[0049] The intermediate heat exchanger 11 and the enthalpy supplement compressor 1 recover the expansion work in the energy release and enthalpy supplement mode, and the heat accumulator 9 increases the mass flow of the supplement gas using the expansion work recovered in the supercooling and energy storage mode, thereby improving the overall performance of the system.

[0050] The presence of the intermediate heat exchanger 11 causes part of the flow at the outlet of the condenser 2 to branch, i.e. the branch where the second three-way valve 8 is located, to achieve supercooling. Compared with a system without supercooling, the expansion work of the system after supercooling is reduced. For ease of understanding, a comparison can be made between a general vapor compression heat pump and a vapor compression heat pump with an intermediate heat exchanger. From the perspective of expansion work, supercooling reduces the expansion work of the system, where the expansion work can be regarded as the loss of expansion work. Therefore, the intermediate heat exchanger 11 achieves supercooling of the fluid, i.e. recovery of the expansion work; and the presence of the enthalpy supplement technology avoids the process of compressing the working fluid after part of it has undergone expansion. Avoiding part of the expansion process, i.e. avoiding part of the expansion work, the expansion work here can be regarded as the lost expansion work. Therefore, the compressor 1 recovers the expansion work in this mode; and the heat accumulator 9 increases the mass flow of the supplement gas, further increasing the recovered expansion work.

[0051] The compressor 1 is a supplement gas compressor. When the system is in the energy release and enthalpy supplement mode, the supplement gas channel of the compressor 1 is open, and the working fluid at the outlet of the heat accumulator 9 acts as the intermediate supplement gas of the compressor 1; when the system is in the supercooling and energy storage mode, the supplement gas port of the compressor 1 is closed, and the supercooling heat of the fluid at the outlet of the condenser 2 is stored in the heat accumulator 9.

[0052] When the system switches to the energy release and enthalpy supplement mode, the fluid at the outlet of the heat accumulator 9 can be used as the intermediate supplement gas of the compressor 1, which can effectively reduce the exhaust temperature of the compressor 1 and overcome the problem of excessively high exhaust temperature of the compression heat pump. When the system switches to the supercooling and energy storage mode, part of the working fluid at the outlet of the condenser 2 enters the heat accumulator 9 to be supercooled, and the released heat can be stored in the heat accumulator 9.

[0053] The compression type high-temperature heat pump system with energy storage and enthalpy supplement has the core features of ejector efficiency increasing technology, air supplement and enthalpy increasing technology, energy storage efficiency increasing technology and mode switching technology, and is constructed by organically integrating various technologies, overcomes the problem of high consumption of high-grade electric energy in the process of low-temperature waste heat grade improvement, and further improves the heat grade conversion efficiency of the heat pump for low-temperature waste heat recovery.

[0054] The compression type high-temperature heat pump system with energy storage and enthalpy supplement disclosed by the application solves the problems of industrial low-temperature waste heat dissipation, large compression ratio of single-stage compression high-temperature heat pump and high compressor exhaust temperature, increases the heat accumulator and air supplement and enthalpy increasing branch on the basis of the ejector-compression type high-temperature heat pump, and realizes efficient recovery of low-grade waste heat and effective reduction of the compressor exhaust temperature.

[0055] The working fluid at the outlet of the condenser 2 is divided into two streams, one stream of fluid is used as the injection fluid of the ejector 4 to improve the inlet pressure of the compressor 1, and the other stream of fluid is used as the high-temperature medium of the energy storage / enthalpy supplement and intermediate heat exchanger to avoid the liquid hammer phenomenon. The two streams of fluid at the outlet of the condenser 3 utilize two expansion work recovery modes, wherein the other stream of fluid is used for the heat accumulator, intermediate heat exchanger and air supplement, enthalpy increasing, intermediate heat exchanger when the supercooling energy storage and energy release supplement enthalpy, respectively. The design of the supercooling energy storage and energy release supplement enthalpy effectively reduces the exhaust temperature of the compressor, improves the system heating efficiency, and has good economic benefits and environmental friendliness.

[0056] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Accordingly, the application is not to be limited to these embodiments shown herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A compression-type high-temperature heat pump system having an energy storage enthalpy supplement, characterized by, The system comprises a compressor (1), a condenser (2), a three-way valve, an expansion valve, an ejector (4), a gas-liquid separator (5), an evaporator (7), a heat accumulator (9) and an intermediate heat exchanger (11), and the system is switched between a supercooling energy storage mode and an energy release enthalpy supplement mode through the three-way valve, wherein the three-way valve comprises a first three-way valve (3) and a second three-way valve (8), and the expansion valve comprises a first expansion valve (10), a second expansion valve (6) and a third expansion valve (12); In the supercooling energy storage mode, the outlet of the compressor (1) is connected with the inlet of the condenser (2), the outlet of the condenser (2) is connected with the inlet of the first three-way valve (3), one of the outlets of the first three-way valve (3) is connected with the ejector (4), and the other outlet is connected with the heat accumulator (9); the outlet of the heat accumulator (9) is connected with the inlet of the first expansion valve (10), the outlet of the first expansion valve (10) is connected with the inlet of the gas-liquid separator (5), the outlet of the ejector (4) is connected with the gas-liquid separator (5), the gas phase outlet of the gas-liquid separator (5) is connected with the intermediate heat exchanger (11), the outlet of the intermediate heat exchanger (11) is connected with the inlet of the compressor (1), the liquid phase outlet of the gas-liquid separator (5) is connected with the second expansion valve (6), the outlet of the second expansion valve (6) is connected with the evaporator (7), and the outlet of the evaporator (7) is connected with the secondary nozzle inlet of the ejector (4); In the energy release enthalpy supplement mode, the outlet of the compressor (1) is connected with the inlet of the condenser (2), the outlet of the condenser (2) is connected with the inlet of the first three-way valve (3), one of the outlets of the first three-way valve (3) is connected with the ejector (4), and the other outlet is connected with the second three-way valve (8), the intermediate heat exchanger (11), the third expansion valve (12) and the heat accumulator (9) in sequence, and the heat accumulator (9) is connected with the air supplement inlet of the compressor (1); the outlet of the ejector (4) is connected with the gas-liquid separator (5), the gas phase outlet of the gas-liquid separator (5) is connected with the inlet of the intermediate heat exchanger (11), the outlet of the intermediate heat exchanger (11) is connected with the compressor (1), and the liquid phase outlet of the gas-liquid separator (5), the second expansion valve (6), the evaporator (7) and the ejector (4) are connected in sequence. In the supercooling energy storage mode, the working fluid is pressurized by the compressor (1) and then enters the condenser (2) to release heat and condense. The condensed working fluid in the condenser (2) is divided into two streams by the first three-way valve (3). One stream enters the primary nozzle of the ejector (4) to complete the pressure reduction and speed increase, and then injects the outlet fluid of the evaporator (7) into the ejector (4), and mixes in the mixing chamber of the ejector (4). The mixed fluid is pressurized by the ejector (4) and then enters the gas-liquid separator (5). The other stream enters the regenerator (9) to release heat, and the released heat is stored in the regenerator (9). The working fluid in the regenerator (9) is cooled and then enters the first expansion valve (10) to reduce pressure. The working fluid after pressure reduction enters the gas-liquid separator (5) and mixes with the outlet fluid of the ejector (4). The gas phase fluid in the gas-liquid separator (5) enters the intermediate heat exchanger (11) to absorb heat and become superheated steam, which enters the compressor (1) to complete the compression process. The liquid phase fluid enters the second expansion valve (6) to reduce pressure, and then enters the evaporator (7) to absorb heat and evaporate. Finally, it is injected into the ejector (4) by the primary stream of the ejector (4).

2. A compression-based high-temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, The ejector (4) can use the high-pressure fluid at the outlet of the condenser (2) to inject the low-pressure fluid at the outlet of the evaporator (7), thereby increasing the pressure of the fluid at the inlet of the compressor (1) and reducing the compression ratio of the compressor (1).

3. A compression high temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, The ejector (4) is an area-adjustable ejector, which adjusts the throat area of the ejector according to the actual operating conditions of the system.

4. The compression-based high-temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, When the system switches to the energy release and enthalpy compensation mode, the outlet fluid of the regenerator (9) is used as the intermediate gas supplement of the compressor (1). When the system switches to the supercooling energy storage mode, part of the working fluid at the outlet of the condenser (2) enters the regenerator (9) to be supercooled, and the released heat is stored in the regenerator (9).

5. A compression high temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, The compressor (1) is a gas-supplemented compressor.

6. A compression-based high-temperature heat pump system with energy accumulation and enthalpy compensation according to claim 5, characterized in that, When the system is in the energy release and enthalpy compensation mode, the gas supplement channel of the compressor (1) is open, and the outlet fluid of the regenerator (9) serves as the intermediate gas supplement of the compressor (1). When the system is in the supercooling energy storage mode, the gas supplement port of the compressor (1) is closed, and the supercooling heat of the outlet fluid of the condenser (2) is stored in the regenerator (9).

7. A compression high temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, In the supercooling energy storage mode, the outlet pressure of the ejector is the same as the pressure of the working fluid after pressure reduction in the branch where the regenerator is located.

8. A compression high temperature heat pump system with energy accumulation and enthalpy compensation according to claim 1, characterized in that, In the energy release and enthalpy compensation mode, the outlet temperature of the regenerator is higher than the outlet temperature of the intermediate heat exchanger, but lower than the condensation temperature.

9. A compression high temperature heat pump system with energy accumulation and enthalpy compensation according to any of claims 1-8, characterized in that, In the energy release and enthalpy compensation mode, the working fluid is compressed and pressurized in the compressor (1), and then mixed with the outlet fluid of the heat accumulator (9). The mixed working fluid is compressed and pressurized in the high-pressure chamber of the compressor (1). The pressurized working fluid enters the condenser (2) to release heat and condense. The condensed working fluid enters the first three-way valve (3) and is divided into two streams. One stream becomes the injection fluid of the ejector (4), enters the ejector (4) to reduce pressure and increase speed, and then injects and mixes with the working fluid at the outlet of the evaporator (7). The mixed fluid enters the ejector (4) to increase pressure, and then enters the gas-liquid separator (5). The other stream enters the intermediate heat exchanger (11) to release heat, and then enters the third expansion valve (12) to expand and reduce pressure. The reduced pressure working fluid absorbs heat from the heat accumulator (9) and then enters the compressor (1) to complete the air compensation. The gaseous working fluid in the gas-liquid separator (5) enters the intermediate heat exchanger (11) to absorb heat and become superheated steam, and then enters the compressor (1) to compress and pressurize. The liquid working fluid in the gas-liquid separator (5) enters the second expansion valve (6) to expand and reduce pressure, and then enters the evaporator (7) to absorb heat and evaporate. The outlet fluid of the evaporator (7) is injected by the working fluid in the ejector (4) and enters the ejector (4).

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