CN115111808B - Compression injection type dual-temperature heat pump system - Google Patents

Abstract

The invention belongs to the technical field of heat pumps, and specifically relates to a compression-injection dual-temperature heat pump system. The invention provides a two-phase flow-driven injector between two condensers with different temperatures to inject gaseous gas from a subcooling heat exchanger. The refrigerant reduces throttling losses and supercools the low-temperature condensate. While achieving dual-temperature heating, it increases the system heating capacity and improves the system COP. Moreover, a working fluid pump and generator are also installed. When there is a low-grade heat source, the low-grade heat source can be used to provide auxiliary heat to further improve the system COP.

Description

A compression injection dual-temperature heat pump system

Technical field

The invention belongs to the technical field of heat pumps, and specifically relates to a compression injection dual-temperature heat pump system.

Background technique

Heat pumps can use low-grade energy in air, water and soil to provide external heating. They are an energy-saving technology with great development prospects. In the traditional heat pump system, it can usually only supply heat to the outside at one temperature. When there is a need for heat supply at two external temperatures, if two sets of heat pump systems are used to provide heat, the equipment investment will be significantly increased; if it is used at high The method of setting a throttling valve between low-temperature condensers causes significant energy loss.

Among the existing heat pump technologies, the patent number is 201310719638.6, titled "Dual Temperature Condensation Two-Stage Compression Heat Pump System". It uses mixed refrigeration and utilizes the different condensation temperatures of different refrigerant components and two-stage compression to achieve dual-temperature condensation. Its dual-temperature heat supply is restricted by the proportion of components and must be achieved through two-stage compression. It also fails to utilize low-grade energy for auxiliary heating. The patent number is 202010655160.5, and the patent is titled "Dual Temperature Air Source Heat Pump Unit". The liquid refrigeration after high temperature condensation is throttled and then enters the low temperature condenser to achieve dual temperature refrigeration. However, the throttling causes energy loss. Although the air is injected The evaporator uses high-temperature condensed gas to suck the gas from the evaporator, which can save a certain amount of energy. However, it is difficult to balance the ejector outlet pressure and the pressure after throttling of the liquid refrigerant, and the low-temperature condensation temperature is also difficult to control. In addition, this patent can only use A single-stage compressor has a low condensation temperature at high temperatures and cannot use low-grade energy for auxiliary heating. The patent number is 201710447513.0, titled "Dual Temperature Output Ground Source Heat Pump". The high-temperature condenser and the low-temperature condenser are only connected by pipelines. Without other measures, the condensation temperature of the low-temperature condenser cannot be controlled.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the existing technology, the present invention proposes a compression injection dual-temperature heat pump system. A two-phase flow-driven injector is provided between two condensers with different temperatures, and the injection comes from the subcooling heat exchanger. The gaseous refrigerant reduces throttling losses and supercools the low-temperature condensate. While achieving dual-temperature heating, it increases the system heating capacity and improves the system COP. In addition, a working fluid pump and generator are also installed. When there is a low-grade heat source, the low-grade heat source can be used to provide auxiliary heat to further improve the system COP.

The present invention adopts the following technical solutions to achieve:

Compression injection dual-temperature heat pump system includes a dual-temperature heat pump circuit. The dual-temperature heat pump circuit includes: a high-temperature condenser, a low-temperature condenser, an ejector, a compressor, an evaporator, a subcooling heat exchanger, and a first expansion valve. , the second expansion valve and the connecting pipeline, wherein the compressor outlet pipeline is connected to the high-temperature condenser inlet pipeline, the high-temperature condenser outlet pipeline is connected to the ejector primary fluid inlet, and the ejector outlet is connected to the low-temperature condenser inlet pipeline. The outlet pipeline of the low-temperature condenser is divided into two lines. The first branch is connected to the first expansion valve, the evaporation side inlet of the subcooling heat exchanger and the secondary fluid inlet of the ejector in turn. The second branch is connected to the subcooling in turn. The heat exchanger, second expansion valve, and evaporator are connected to the compressor inlet.

Furthermore, the compression injection dual-temperature heat pump system also includes a low-grade energy efficiency loop. The low-grade energy efficiency loop includes: a working fluid pump, a generator, a second check valve and its connecting pipeline. , the branch branch on the pipeline between the subcooling heat exchanger and the second expansion valve is connected to the inlet of the working fluid pump, the outlet pipeline of the working fluid pump is connected to the refrigerant inlet pipeline of the generator, the compressor and the high-temperature condensation The branch line on the pipeline between the generators is connected to the second check valve and the generator refrigerant outlet pipeline.

In order to achieve dual-temperature heating, the gas-liquid mixed refrigerant condensed in the high-temperature condenser needs to be further cooled and decompressed before entering the low-temperature condenser. The expansion valve throttling method is usually used, but this causes significant throttling losses. This application uses an ejector instead of an expansion valve, and can use the pressure drop of the gas-liquid mixed fluid to pump the secondary fluid. The outlet pipeline of the low-temperature condenser is divided into two circuits. After the gas-liquid mixed refrigerant in the first branch passes through the first expansion valve, it is cooled and decompressed, and then absorbs the refrigerant in the second branch in the subcooling heat exchanger. The heat causes the gas-liquid mixed refrigerant in the low-temperature and low-pressure state in the first branch to change into gaseous refrigerant.

The refrigerant vapor that evaporates and absorbs heat in the subcooling heat exchanger increases the amount of steam flowing into the low-temperature condenser and increases the condensation heat supply. At the same time, the fluid in the first branch of the subcooling heat exchanger evaporates. , absorbs the heat of the refrigerant flowing to the evaporator in the second branch, making it supercooled, reducing the enthalpy value of the evaporator inlet, increasing the evaporation heat absorption, and significantly improving the system COP.

When there is a low-grade heat source, part of the subcooled refrigerant from the subcooling heat exchanger is pressurized by the working medium pump and then enters the generator, which can absorb more heat. After absorbing heat, the refrigerant enters the high-temperature condenser, making full use of Low-grade energy, compressor frequency conversion reduces suction volume, reduces compressor power consumption, and system COP is greatly improved.

Furthermore, one or more of the injectors are connected in parallel.

Further, the driving energy of the generator is solar energy, geothermal energy or industrial waste heat. In the compression injection dual-temperature heat pump system, when there is no low-grade energy drive, the low-grade energy efficiency circuit stops working, and the single-stage compression dual-temperature heat pump circuit operates independently; when no low-grade energy is available, the compression The injection dual-temperature heat pump system can be composed of a single-stage compression dual-temperature heat pump circuit.

Further, the dual-temperature heat pump circuit also includes a third expansion valve and a gas-liquid separator. The gas-liquid separator has one inlet and two outlets. The inlet is the first inlet, and the outlets are the first outlet and the second outlet. The first outlet is the gas refrigerant outlet, the second outlet is the liquid refrigerant outlet, the evaporation side inlet of the subcooling heat exchanger is connected to the first inlet of the gas-liquid separator, and the first outlet of the gas-liquid separator is connected to the injection The second fluid inlet of the gas-liquid separator is connected to the third expansion valve and the evaporator and compressor inlets through pipelines.

A gas-liquid separator is provided between the outlet of the subcooling heat exchanger and the secondary fluid inlet of the ejector, so that the refrigerant at the first branch outlet of the subcooling heat exchanger is separated into gas and liquid in the gas-liquid separator. When the system pressure fluctuates, the secondary fluid in the ejector is steam, and when the suction force of the ejector increases, the liquid in the gas-liquid separator evaporates, which can increase the supply of secondary fluid to the ejector and improve the system's adaptability to pressure fluctuations. Stronger.

Further, the outlet pipelines of the second expansion valve and the third expansion valve are merged into one pipeline through a tee to connect to the evaporator inlet.

Further, the compressor may be a volumetric compressor or a velocity compressor.

Further, the gas-liquid separator also has a third outlet, which is a liquid refrigerant outlet or a gas refrigerant outlet. The third outlet of the gas-liquid separator is connected to the regulating valve and the third outlet in sequence through pipelines. A check valve and an intermediate refrigerant charge port of a compressor with a refrigerant charge port.

Further, the third outlet of the gas-liquid separator is a liquid refrigerant outlet, and the compressor with a refrigerant replenishment inlet is an intermediate rehydration compressor. The third outlet of the gas-liquid separator is a gas refrigerant outlet, and the compressor with a refrigerant replenishment inlet is an intermediate air replenishment compressor.

The gas or liquid refrigerant in the gas-liquid separator is supplied to the compressor under the action of pressure difference, and the flow rate of the refrigerant is adjusted through the regulating valve. The technical effect is that the refrigerant in the gas-liquid separator is added to the compressor, which can reduce the intermediate temperature of the compressor, thereby reducing the exhaust temperature of the compressor, increase the compressor pressure ratio and heat supply, and enhance The system is adaptable to working conditions with low evaporation temperature and high temperature and high condensation temperature. When the working conditions change (especially when the heat from low-grade heat sources such as solar energy changes greatly), the adjustment of the air supply flow rate by the regulating valve is coordinated with the frequency conversion of the compressor. , allowing the system to make full use of low-grade energy and maintain stable and efficient operation.

Furthermore, it can also include two sets of compressors, including a low-pressure stage compressor and a high-pressure stage compressor. The gas-liquid separator also has an inlet as a second inlet and an outlet as a third outlet. The third outlet is Gaseous refrigerant outlet; the high-pressure compressor outlet pipeline is connected to the high-temperature condenser inlet pipeline, the third outlet of the gas-liquid separator is connected to the high-pressure compressor inlet, the evaporator is connected to the low-pressure compressor inlet, and the low-pressure stage compression The outlet of the machine is connected with the second inlet of the gas-liquid separator.

The refrigerant at the outlet of the low-pressure stage compressor is discharged into the gas-liquid separator, so that the gas-liquid separator plays the role of subcooling and heat exchange.

The gas-liquid separation function of the gas-liquid separator makes the ejector work more stable and efficient, while the cooling and heat exchange function of the gas-liquid separator cools the refrigerant vapor at the outlet of the low-pressure compressor, reduces the superheat, and then enters the high-pressure compressor. , which can reduce the exhaust temperature of the high-pressure compressor and significantly improve the suction volume and system performance of the high-pressure compressor.

Further, there is a heat exchange coil in the gas-liquid separator, the second inlet of the gas-liquid separator is connected to the inlet of the heat exchange coil, and the third outlet of the gas-liquid separator is connected to the outlet of the heat exchange coil. . The gas-liquid separator may also be in the form of no heat exchange coil.

The beneficial effects produced by the present invention compared with the existing technology are:

1. Use low-grade energy as the auxiliary heat source of the heat pump to improve the energy efficiency of the heat pump and achieve energy conservation and carbon reduction;

2. Set up a two-stage condenser (high temperature/low temperature), which can provide condensation heat at two different temperatures at the same time, achieving dual uses in one machine. If used for domestic hot water heating, the water can be preheated by the low temperature condenser before entering High-temperature condenser significantly increases heat transfer and improves heat pump performance;

3. Utilize a two-phase ejector with simple structure, low cost and high reliability to achieve temperature and pressure reduction while simultaneously sucking the gaseous refrigerant from the subcooling heat exchanger, which increases the low-temperature condensation heat and reduces the enthalpy of the evaporator inlet. value, increasing the evaporation heat absorption and improving system performance;

4. When low-grade heat sources provide auxiliary heating, the flow of refrigerant can be adjusted through compressor frequency conversion and control valve adjustment according to the heat supply, which enhances the system's adaptability to changes in working conditions and can make full use of low-grade heat sources. High-grade heat source to improve system COP;

5. The gas-liquid separator can stabilize the system pressure. At the same time, the cooling and heat exchange effect of the gas-liquid separator in the two-stage compression can reduce the exhaust temperature of the high-pressure stage compressor and significantly improve the suction volume and system performance of the high-pressure stage compressor. .

Description of the drawings

Figure 1 is a schematic structural diagram of a compression injection dual-temperature heat pump system (single-stage compression form) of the present invention;

Figure 2 is a schematic structural diagram of a compression injection dual-temperature heat pump system (single-stage compression gas-liquid separation form) of the present invention;

Figure 3 is a schematic structural diagram of a compression injection dual-temperature heat pump system (in the form of intermediate refrigerant supplementation and supercharging) according to the present invention;

Figure 4 is a schematic structural diagram of a compression injection dual-temperature heat pump system (two-stage compression form) of the present invention;

Figure 5 is a schematic structural diagram of a gas-liquid separator of a compression injection dual-temperature heat pump system (single-stage compression gas-liquid separation form) of the present invention;

Figure 6 is a schematic structural diagram of a gas-liquid separator (the third outlet is at the gas end) of a compression injection dual-temperature heat pump system (in the form of intermediate refrigerant supplementation and supercharging) of the present invention;

Figure 7 is a schematic structural diagram of a gas-liquid separator (the third outlet is at the liquid end) of a compression injection dual-temperature heat pump system (in the form of intermediate refrigerant supplementation and supercharging) of the present invention;

Figure 8 is a schematic structural diagram of a gas-liquid separator (without heat exchange coil form) of a compression injection dual-temperature heat pump system (two-stage compression form) of the present invention;

Figure 9 is a schematic structural diagram of a gas-liquid separator (in the form of a heat exchange coil) of a compression injection dual-temperature heat pump system (two-stage compression form) of the present invention;

In the picture: 1-high temperature condenser, 2-ejector, 3-low temperature condenser, 4-subcooling heat exchanger, 5-first expansion valve, 6-second expansion valve, 7-gas-liquid separator, 8 -Check valve, 9-third expansion valve, 10-evaporator, 11-compressor with refrigerant supplementary inlet, 12-compressor, 13a-low-pressure stage compressor, 13b-high-pressure stage compressor, 14-work Mass pump, 15-generator, 16-second check valve, 17-regulating valve;

701-first inlet, 702-first outlet, 703-second outlet, 704-third outlet, 705-second inlet, 706-heat exchange coil, 707-oil return port.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear, the present invention will be further described in detail with reference to the embodiments and drawings. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention. The technical solution of the present invention will be described in detail below with reference to the embodiments and drawings, but the scope of protection is not limited by this.

Example 1

Figure 1 is a schematic diagram of the overall structure of the compression injection dual-temperature heat pump system (single-stage compression form) in Embodiment 1. This system is suitable for situations where the high-temperature condensation temperature is not too high and the evaporation temperature is not too low.

As shown in Figure 1, the compression injection dual-temperature heat pump system (single-stage compression form) includes a single-stage compression dual-temperature heat pump circuit and a low-grade energy efficiency circuit. The single-stage compression dual-temperature heat pump circuit includes: high-temperature condenser 1, low-temperature condenser 3, ejector 2, compressor 12, evaporator 10, subcooling heat exchanger 4, first expansion valve 5, second expansion valve 6 and Connect the pipes. Among them, the outlet pipeline of compressor 12 is connected to the inlet of high-temperature condenser 1, the outlet of high-temperature condenser 1 is connected to the primary fluid inlet of ejector 2, the outlet of ejector 2 is connected to the inlet pipeline of low-temperature condenser 3, and the outlet pipe of low-temperature condenser 3 The road is divided into two. The first branch is connected to the first expansion valve 5, the evaporation side inlet of the subcooling heat exchanger 4 and the secondary fluid inlet of the ejector 2 in sequence. The second branch is connected to the subcooling heat exchanger 4 in sequence. , the second expansion valve 6, the evaporator 10 and the compressor 12 inlet.

The low-grade energy efficiency loop includes: working fluid pump 14, generator 15, second check valve 16 and its connecting pipeline. The combination of the low-grade energy efficiency loop and the single-stage compression dual-temperature heat pump loop is as follows: the branch branch on the pipeline between the subcooling heat exchanger 4 and the second expansion valve 6 is connected to the inlet of the working fluid pump 14, and the working fluid The outlet pipeline of the pump 14 is connected to the refrigerant inlet pipeline of the generator 15, and a branch pipeline on the pipeline between the compressor 12 and the high temperature condenser 1 is connected to the refrigerant outlet pipeline of the generator 15.

When the low-grade heat source can provide heat for the generator 15, the heat pump system operates in the low-grade energy efficiency mode: the gaseous refrigerant at the outlet of the compressor 12 is mixed with the gaseous refrigerant from the generator 15, enters the high-temperature condenser 1 and is condensed. After partial condensation, the gas-liquid mixed refrigerant enters the ejector 2 to reduce the pressure, and sucks the gas from the evaporation side of the subcooling heat exchanger 4. After the two are mixed and pressurized, they enter the low-pressure condenser 3 and are condensed into a liquid state. The refrigerant is divided into Two paths: The first path of liquid refrigerant enters the liquid channel of the subcooling heat exchanger 4, and is divided into two paths after being subcooled. The refrigerant in one path is throttled and decompressed by the second expansion valve 6, and then flows to In the evaporator 10, the refrigerant in the other branch is pressurized by the working fluid pump 14 and then enters the generator 15 for evaporation; the liquid refrigerant in the second path is throttled and decompressed by the first expansion valve 5 and then enters the subcooling heat exchanger. 4 in the evaporation channel, the evaporation absorbs heat and then enters the secondary fluid inlet of the injector 2.

When there is no low-grade heat source to supply heat to the generator 15, the heat pump system operates in basic mode. The difference from the low-grade energy efficiency mode is that: no gaseous refrigerant flows to the high-temperature condenser in the generator 15, only the gaseous refrigerant from the compressor 12 enters the high-temperature condenser 1 for condensation; After passing through the subcooling heat exchanger 4 , the refrigerant all passes through the second expansion valve 6 , but no refrigerant flows to the working medium pump 14 , and is mixed with the refrigerant flowing out of the third expansion valve 9 before entering the evaporator 10 . Except for the above process, the rest of the process is the same as the low-grade energy efficiency model.

Example 2

Figure 2 is a schematic diagram of the overall structure of the compression injection dual-temperature heat pump system (single-stage compression gas-liquid separation form) in Embodiment 2. This system is suitable for situations where the high-temperature condensation temperature is not too high and the evaporation temperature is not too low. The structure of the gas-liquid separator 7 in this system is shown in Figure 5.

As shown in Figure 2, the compression injection dual-temperature heat pump system (single-stage compression gas-liquid separation form) includes a single-stage compression gas-liquid separation dual-temperature heat pump circuit and a low-grade energy efficiency circuit. The single-stage compressed gas-liquid separation dual-temperature heat pump circuit includes: high-temperature condenser 1, low-temperature condenser 3, ejector 2, compressor 12, evaporator 10, subcooling heat exchanger 4, first expansion valve 5, second Expansion valve 6, third expansion valve 9, gas-liquid separator 7 and connecting pipelines. Among them, the outlet pipeline of compressor 12 is connected to the inlet pipeline of high-temperature condenser 1, the outlet pipeline of high-temperature condenser 1 is connected to the primary fluid inlet of ejector 2, the outlet of ejector 2 is connected to the inlet pipeline of low-temperature condenser 3, and the low-temperature condensation The outlet pipeline of the device 3 is divided into two lines. The first branch is connected to the first expansion valve 5, the subcooling heat exchanger 4 and the first inlet 701 of the gas-liquid separator 7 in sequence; the second branch is connected to the subcooling heat exchanger in sequence. The inlets of the evaporator 4, the second expansion valve 6, the evaporator 10 and the compressor 12, the first outlet 702 of the gas-liquid separator 7 is connected to the secondary fluid inlet of the ejector, and the second outlet 703 of the gas-liquid separator passes through the pipeline. The third expansion valve 9 is connected to the inlets of the evaporator 10 and the compressor 12 in sequence. The gas-liquid separator 4 has two outlets. The first outlet 702 of the gas-liquid separator 4 is a gas refrigerant outlet. This outlet is connected to the ejector. The secondary fluid inlet of 2 is connected; the second outlet 703 of the gas-liquid separator 4 is a liquid refrigerant outlet, which is connected to the third expansion valve 9 and the inlet of the evaporator 10 through pipelines.

The low-grade energy efficiency loop includes: working fluid pump 14, generator 15, second check valve 16 and its connecting pipeline. It is completely consistent with Example 1, so it will not be described again.

When the low-grade heat source can provide heat for the generator 15, the heat pump system operates in the low-grade energy efficiency mode: the gaseous refrigerant at the outlet of the compressor 12 is mixed with the gaseous refrigerant from the generator 15, enters the high-temperature condenser 1 and is condensed. After partial condensation, the gas-liquid mixed refrigerant enters the ejector 2 to reduce the pressure, and sucks the gas from the gas-liquid separator 7. After the two are mixed and pressurized, they enter the low-pressure condenser 3 and are condensed into a liquid state. The refrigerant is divided into two paths: The first liquid refrigerant enters the liquid channel of the subcooling heat exchanger 4 and is subcooled and divided into two branches. The refrigerant in one branch is throttled and decompressed by the second expansion valve 6 and then flows to the evaporator 10 , the refrigerant in the other branch is pressurized by the working fluid pump and then enters the generator 15 to evaporate; the liquid refrigerant in the second branch is throttled and decompressed by the first expansion valve 5 and then enters the evaporation channel of the subcooling heat exchanger 4, After evaporating and absorbing heat, it enters the gas-liquid separator 7. The liquid refrigerant after gas-liquid separation is throttled and decompressed by the third expansion valve 9, mixed with the refrigerant from the second expansion valve 6, and then enters the evaporator 10 to evaporate. Enter the compressor 12 to boost the pressure.

When there is no low-grade heat source to supply heat to the generator 15, the heat pump system operates in basic mode. The difference from the low-grade energy efficiency mode is that: no gaseous refrigerant in the generator 15 flows to the high-temperature condenser 1, only the gaseous refrigerant from the compressor 12 enters the high-temperature condenser 1 for condensation; after condensation in the low-temperature condenser 3 After the first-pass refrigerant passes through the subcooling heat exchanger 4, it all passes through the second expansion valve 6, mixes with the refrigerant flowing out of the third expansion valve 9, and then enters the evaporator 10. Except for the above process, the rest of the process is the same as the low-grade energy efficiency model.

Example 3

Figure 3 is a schematic structural diagram of a compression injection dual-temperature heat pump system (in the form of intermediate refrigerant supplementation and supercharging) in Embodiment 3. This system is suitable for situations where the high-temperature condensation temperature is high and the evaporation temperature is low. The structure of the gas-liquid separator 7 in this system is shown in Figure 6.

As shown in Figure 3, the compression injection dual-temperature heat pump system (in the form of supercharging with intermediate refrigerant) includes a dual-temperature heat pump circuit with intermediate refrigerant and a low-grade energy efficiency circuit. The dual-temperature heat pump circuit with refrigerant supplemented in the middle includes: high-temperature condenser 1, low-temperature condenser 3, ejector 2, compressor (with refrigerant supplement inlet) 11, evaporator 10, subcooling heat exchanger 4, first Expansion valve 5, second expansion valve 6, third expansion valve 9, gas-liquid separator 7, first check valve 8, regulating valve 17 and connecting pipelines. Compared with the single-stage compression gas-liquid separation mode, an intermediate gas and liquid supply pipeline is added to the compressor, in which the compressor 11 is a compressor with a refrigerant supply inlet, and the third outlet 704 of the gas-liquid separator 7 is liquid refrigerant. The outlet or the gas refrigerant outlet is connected to the regulating valve 17, the first check valve 8 and the middle liquid injection port of the compressor (with refrigerant supplementary port) 11 through pipelines. The remaining components are completely the same as those in Embodiment 2. They are the same, so the implementation will not be described again.

Another situation in Embodiment 3 is that the third outlet 704 of the gas-liquid separator 7 is a gas refrigerant outlet, which passes through the pipeline and the regulating valve 17, the first check valve 8 and the compressor (with a refrigerant supplementary inlet) 11 is connected to the middle air supply port.

The low-grade energy efficiency loop includes: working fluid pump 14, generator 15, second check valve 16 and its connecting pipeline. The combination of the low-grade energy efficiency circuit and the dual-temperature heat pump circuit with refrigerant added in the middle is as follows: the branch branch on the pipeline between the subcooling heat exchanger 4 and the second expansion valve 6 is connected to the inlet of the working fluid pump 14 , the outlet pipeline of the working fluid pump 14 is connected to the refrigerant inlet pipeline of the generator 15, and the branch pipeline between the compressor (with refrigerant supplementary inlet) 11 and the high-temperature condenser 1 is connected to the refrigerant outlet of the generator 15 Pipes are connected.

When the low-grade heat source can provide heat for the generator 15, the heat pump system operates in the low-grade energy efficiency mode: the gaseous refrigerant at the outlet of the compressor (with refrigerant supplementary inlet) 11 is mixed with the gaseous refrigerant from the generator 15 and enters It is condensed in the high-temperature condenser 1. After partial condensation, the gas-liquid mixed refrigerant enters the ejector 2 to reduce the pressure and sucks the gas from the gas-liquid separator 7. After the two are mixed and pressurized, they enter the low-pressure condenser 3 and are condensed into liquid. The refrigerant is divided into two paths: the first path of liquid refrigerant enters the liquid channel of the subcooling heat exchanger 4, and is divided into two paths after being subcooled. The refrigerant in one path is throttled down by the second expansion valve 6. pressure, and then flows to the evaporator 10. The refrigerant in the other branch is pressurized by the working fluid pump 14 and then enters the generator 15 to evaporate; the liquid refrigerant in the second path is throttled and decompressed by the first expansion valve 5 and then enters the The evaporation channel of the cold heat exchanger 4 enters the gas-liquid separator 7 after evaporating and absorbing heat. Part of the gaseous refrigerant after gas-liquid separation enters the ejector secondary fluid inlet, and the other part passes through the regulating valve 17 and connects with the first check valve 8 and then enters the middle air supply port of the compressor (with refrigerant supply port) 11. The liquid refrigerant after gas-liquid separation is throttled and decompressed by the third expansion valve 9 and mixed with the refrigerant from the second expansion valve 6 before entering. The refrigerant evaporates in the evaporator 10 and then enters the compressor (with a refrigerant charge port) 11 to increase the pressure.

For the case of using an intermediate rehydration compressor, the gaseous refrigerant after being separated by the gas-liquid separator 7 enters the secondary fluid inlet of the ejector 2. A part of the liquid refrigerant after gas-liquid separation passes through the regulating valve 17 and the first check valve. 8 and then enters the middle liquid injection port of the compressor (with refrigerant supplementary inlet) 11. The other part is throttled and decompressed by the third expansion valve 9 and mixed with the refrigerant from the second expansion valve 6 before entering the evaporator 10 for evaporation. , and then enters the compressor (with refrigerant charge port) 11 to boost the pressure.

When there is no low-grade heat source to supply heat to the generator 15, the heat pump system operates in basic mode. The difference from the low-grade energy efficiency mode is that no gaseous refrigerant flows to the high-temperature condenser in the generator 15, and only the gaseous refrigerant from the compressor (with refrigerant supplementary inlet) 11 enters the high-temperature condenser 1 for condensation; After the first refrigerant condensed by the condenser 3 passes through the subcooling heat exchanger 4, all the refrigerant passes through the second expansion valve 6, but no refrigerant flows to the working fluid pump 14, and is mixed with the refrigerant flowing out of the third expansion valve 9. Enter evaporator 10. Except for the above process, the rest of the process is the same as the low-grade energy efficiency model.

Example 4

Figure 4 is a schematic structural diagram of the compression injection dual-temperature heat pump (two-stage compression form) in Embodiment 4. This system is suitable for situations where the evaporation temperature is low and the high temperature and condensation temperature are high. The structure of the gas-liquid separator 7 in this system is shown in Figure 7.

As shown in Figure 4, the compression injection dual-temperature heat pump (two-stage compression form) includes a two-stage compression dual-temperature heat pump circuit and a low-grade energy efficiency circuit. The two-stage compression dual-temperature heat pump circuit includes a high-temperature condenser 1, a low-temperature condenser 3, an ejector 2, a low-pressure stage compressor 13a, a high-pressure stage compressor 13b, an evaporator 10, a subcooling heat exchanger 4, and a first expansion valve 5 , the second expansion valve 6, the third expansion valve 9, the gas-liquid separator 7 and the connecting pipeline, wherein the outlet pipeline of the high-pressure stage compressor 13b is connected to the inlet of the high-temperature condenser 1, and the outlet of the high-temperature condenser 1 is connected to The primary fluid inlet of the ejector 2 is connected, and the outlet of the ejector 2 is connected with the inlet of the low-temperature condenser 3. The outlet pipeline of the low-temperature condenser 3 is divided into two lines. The first branch is connected to the first expansion valve 5 and the subcooling in turn. The first inlet 701 of the heat exchanger 4 and the gas-liquid separator 7; the second branch is connected in sequence to the inlet of the subcooling heat exchanger 4, the second expansion valve 6, the evaporator 10 and the low-pressure stage compressor 13a; the gas-liquid separator The first outlet 702 of 7 is connected to the secondary fluid inlet of the ejector 2, and the second outlet 703 of the gas-liquid separator 7 is connected to the third expansion valve 9 and the evaporator 10 and the inlet of the low-pressure stage compressor 13a through pipelines. The outlet of the first-stage compressor 13a is connected to the second inlet 705 of the gas-liquid separator 7, and the third outlet 704 of the gas-liquid separator 7 is connected to the inlet of the high-pressure stage compressor 13b.

The first outlet 702 of the gas-liquid separator is a gas refrigerant outlet, the second outlet 703 is a liquid refrigerant outlet, and the third outlet 704 is a gas refrigerant outlet; the gas-liquid separator can take two forms, one is gas-liquid separation There is no heat exchange coil in the gas-liquid separator 7, and the other is a heat exchange coil 706 in the gas-liquid separator 7. In this case, the second inlet 705 of the gas-liquid separator 7 is in contact with the heat exchange coil. The inlet of 706 is connected, and the third outlet 704 of the gas-liquid separator is connected with the outlet of the heat exchange coil 706.

The low-grade energy efficiency loop includes: working fluid pump 14, generator 15, second check valve 16 and its connecting pipeline. The combination of the low-grade energy efficiency loop and the two-stage compression dual-temperature heat pump loop is as follows: the branch branch on the pipeline between the subcooling heat exchanger 4 and the second expansion valve 6 is connected to the inlet of the working fluid pump 14, and the working fluid The outlet pipeline of the pump 14 is connected to the refrigerant inlet pipeline of the generator 15, and the branch pipeline between the high-pressure stage compressor 13b and the high-temperature condenser 1 is connected to the refrigerant outlet pipeline of the generator 15.

When the low-grade heat source can provide heat for the generator 15, the heat pump system operates in the low-grade energy efficiency mode: the gas refrigerant at the outlet of the high-pressure stage compressor 13b mixes with the gas refrigerant from the generator 15 and enters the high-temperature condenser 1 Condensation, after partial condensation, the gas-liquid mixed refrigerant enters the ejector 2 to reduce the pressure, and sucks the gas from the gas-liquid separator 7. After the two are mixed and pressurized, they enter the low-pressure condenser 3 and condense into a liquid state. The refrigerant is divided into two parts. Path: The first path of liquid refrigerant enters the liquid channel of the subcooling heat exchanger 4. After being subcooled, it enters into two paths. In one path, the refrigerant is throttled and decompressed by the second expansion valve 6, and then flows to evaporation. The refrigerant in the other branch is pressurized by the working medium pump 14 and then enters the generator 15 for evaporation; the liquid refrigerant in the second path is throttled and decompressed by the first expansion valve 5 and then enters the subcooling heat exchanger 4 Evaporation channel, after evaporating and absorbing heat, it enters the gas-liquid separator 7.

For the case where there is no heat exchange coil in the gas-liquid separator 7, the superheated refrigerant vapor from the outlet of the low-pressure stage compressor 13a enters the gas-liquid separator 7 and releases heat, causing part of the liquid refrigerant in the gas-liquid separator 7 to absorb heat. Evaporates into gaseous refrigerant. Part of the gaseous refrigerant in the gas-liquid separator 7 enters the secondary fluid inlet of the ejector 2, and the other part flows to the outlet of the high-pressure stage compressor 13b. After being pressurized, it is mixed with the gaseous refrigerant from the generator 15. , enters the high-temperature condenser 1 again; the liquid refrigerant in the gas-liquid separator 7 is throttled and decompressed by the third expansion valve 9, mixed with the refrigerant from the second expansion valve 6, enters the evaporator 10 to evaporate, and then enters The pressure is increased in the low-pressure stage compressor 13a.

For the case where there is a heat exchange coil 706 in the gas-liquid separator 7 , the superheated refrigerant vapor from the outlet of the low-pressure stage compressor 13 a enters the heat exchange plate in the gas-liquid separator 7 through the second inlet 705 of the gas-liquid separator 7 After the pipe 706 releases heat and cools down through the heat exchange coil 706, it enters the high-pressure stage compressor 13b from the third outlet 704 of the gas-liquid separator 7, causing part of the liquid refrigerant in the gas-liquid separator 7 to absorb heat and evaporate into gaseous refrigerant. , after the gaseous refrigerant at the outlet of the high-pressure stage compressor 13b is mixed with the gaseous refrigerant from the generator 15, it enters the high-temperature condenser 1 again; the gaseous refrigerant in the gas-liquid separator 7 enters the second part of the ejector 2 through the first outlet 702. At the secondary fluid inlet, the liquid refrigerant in the gas-liquid separator 7 enters the third expansion valve 9 through the second outlet 703, is throttled and decompressed, mixed with the refrigerant from the second expansion valve 6, and enters the evaporator 10 to evaporate. Then it enters the low-pressure stage compressor 13a to boost the pressure.

When there is no low-grade heat source to supply heat to the generator 15, the heat pump system operates in basic mode. The difference from the low-grade energy efficiency mode is that: no gaseous refrigerant in the generator 15 flows to the high-temperature condenser, only the gaseous refrigerant from the high-pressure stage compressor 13b enters the high-temperature condenser 1 for condensation; after condensation in the low-temperature condenser 3 After the first-pass refrigerant passes through the subcooling heat exchanger 4, all of it passes through the second expansion valve 6, but no refrigerant flows to the working medium pump 14. It mixes with the refrigerant flowing out of the third expansion valve 9 and then enters the evaporator 10. Except for the above process, the rest of the process is the same as the low-grade energy efficiency model.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be concluded that the specific embodiments of the present invention are limited to this. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the premise of the present invention, Below, several simple deductions or substitutions can be made, which should all be deemed to belong to the patent protection scope of the present invention as determined by the submitted claims.

Claims (10)

1. The compression injection type double-temperature heat pump system is characterized by comprising a double-temperature heat pump loop, wherein the double-temperature heat pump loop comprises: high temperature condenser (1), low temperature condenser (3), sprayer (2), compressor (12), evaporimeter (10), subcooling heat exchanger (4), first expansion valve (5), second expansion valve (6) and connecting line, wherein, compressor (12) export pipeline links to each other with high temperature condenser (1) entry pipeline, high temperature condenser (1) export links to each other with sprayer (2) primary fluid entry, sprayer (2) export links to each other with low temperature condenser (3) entry pipeline, low temperature condenser (3) export pipeline divide into two-way, first branch road connects gradually first expansion valve (5), subcooling heat exchanger (4) evaporation side entry is linked together with sprayer (2) secondary fluid entry, second branch road connects gradually subcooling heat exchanger (4), second expansion valve (6), evaporator (10) back links to each other with compressor (12) entry.

2. The dual temperature heat pump system of claim 1, further comprising a low grade energy efficiency enhancing circuit comprising: working medium pump (14), generator (15), second check valve (16) and connecting line thereof, branch road links to each other with the entry of working medium pump (14) on the pipeline between supercooling heat exchanger (4) and second expansion valve (6), and working medium pump (14) outlet line links to each other with the refrigerant entry pipeline of generator (15), and branch road links to each other with second check valve (16) and generator (15) refrigerant outlet line on the pipeline between compressor (12) and high temperature condenser (1).

3. A compression-injection dual-temperature heat pump system according to claim 2, characterized in that the injectors (2) are one or more in parallel.

4. A compression-injection dual-temperature heat pump system according to claim 3, characterized in that the driving energy of the generator (15) is solar energy, geothermal energy or industrial waste heat.

5. The compression-injection dual-temperature heat pump system as claimed in claim 4, wherein the dual-temperature heat pump circuit further comprises a third expansion valve (9) and a gas-liquid separator (7), the gas-liquid separator (7) has one inlet and two outlets, the inlet is a first inlet (701), the outlet is a first outlet (702) and a second outlet (703), the first outlet (702) is a gaseous refrigerant outlet, the second outlet (703) is a liquid refrigerant outlet, the evaporation side inlet of the supercooling heat exchanger (4) and the first inlet (701) of the gas-liquid separator (7) are connected, the first outlet (702) of the gas-liquid separator (7) is connected with the secondary fluid inlet of the ejector (2), and the second outlet (703) of the gas-liquid separator (7) is connected with the third expansion valve (9) and the evaporator (10) and the inlet of the compressor (12) through pipelines.

6. The compression-injection dual-temperature heat pump system as claimed in claim 5, wherein the gas-liquid separator (7) further has a third outlet (704), the third outlet (704) is a liquid refrigerant outlet or a gaseous refrigerant outlet, and the third outlet (704) of the gas-liquid separator (7) is sequentially connected to an intermediate refrigerant supply port of the regulating valve (17), the first check valve (8) and the compressor (11) with the refrigerant supply port through a pipeline.

7. The compression-injection dual-temperature heat pump system according to claim 6, characterized in that the third outlet (704) of the gas-liquid separator (7) is a liquid refrigerant outlet, and the compressor (11) with a refrigerant charge inlet is an intermediate charge compressor.

8. The compression-injection dual-temperature heat pump system according to claim 6, characterized in that the third outlet (704) of the gas-liquid separator (7) is a gaseous refrigerant outlet and the compressor (11) with refrigerant make-up inlet is an intermediate make-up compressor.

9. The compression-injection dual-temperature heat pump system according to claim 5, wherein the compressors comprise two groups, including a low-pressure stage compressor (13 a) and a high-pressure stage compressor (13 b), the gas-liquid separator (7) further having one inlet being a second inlet (705) and one outlet being a third outlet (704), the third outlet (704) being a gaseous refrigerant outlet; the outlet pipeline of the high-pressure stage compressor (13 b) is connected with the inlet pipeline of the high-temperature condenser (1), the third outlet (704) of the gas-liquid separator (7) is connected with the inlet of the high-pressure stage compressor (13 b), the evaporator (10) is connected with the inlet of the low-pressure stage compressor (13 a), and the outlet of the low-pressure stage compressor (13 a) is connected with the second inlet (705) of the gas-liquid separator (7).

10. The compression-injection dual-temperature heat pump system as claimed in claim 9, wherein the gas-liquid separator (7) is internally provided with a heat exchange coil (706), the second inlet (705) of the gas-liquid separator is connected with the inlet of the heat exchange coil (706), and the third outlet (704) of the gas-liquid separator is connected with the outlet of the heat exchange coil (706).