Mixed working medium heat pump system

Abstract

The invention relates to the technical field of heating equipment, in particular to a mixed working medium heat pump system which comprises a compressor, a primary gas-liquid separator, an evaporative condenser and a main evaporator, and further comprises a gas phase pipeline connected between the gas phase output end of the primary gas-liquid separator and the input end of the main evaporator, and a liquid storage device is installed on the gas phase pipeline; the liquid phase pipeline is connected between the liquid phase output end of the primary gas-liquid separator and the input end of the main evaporator, one end of the auxiliary backflow pipeline is communicated with the liquid phase pipeline and located on the downstream of the evaporative condenser, the other end of the auxiliary backflow pipeline is communicated with an output end pipeline of the main evaporator, and the auxiliary backflow pipeline can be arranged in an on-off mode. When working in a small working temperature difference environment, only the high-boiling-point working medium completes the whole circulation; when working in a large working temperature difference environment, the high-boiling-point working medium and the low-boiling-point working medium jointly complete the whole circulation. Therefore, the mixed working medium heat pump system can keep higher heating efficiency under the environment of large working temperature difference in winter and small working temperature difference in summer.

Description

Technical Field

[0001] The present invention relates to the technical field of heating equipment, and particularly relates to a hybrid refrigerant heat pump system. Background Art

[0002] In severely cold regions in winter, the lowest outdoor ambient temperature can reach -45°C. Calculated according to the domestic water supply temperature of 50°C, the maximum working temperature difference required for the heating heat pump is 95°C. A single-refrigerant cycle heat pump cannot meet the requirements. In order to meet the operating requirements of a high working temperature difference in severely cold regions, when a single-refrigerant heat pump is used for heating in severely cold regions in winter, other auxiliary heat sources need to be combined to meet the requirements, but this solution has a high investment cost and high operating costs.

[0003] In order to reduce the winter heating cost in severely cold regions in winter, a hybrid refrigerant cycle heat pump system is used for heating in the prior art, and the maximum working temperature difference can reach 120°C, which can well meet the winter heating requirements in severely cold regions in winter. The existing hybrid refrigerant cycle heat pump system mainly includes components such as a compressor, a condenser, a gas-liquid separator, an evaporative condenser, a throttle valve, and an evaporator. During operation, the hybrid refrigerant is compressed by the compressor and then flows through the condenser and the gas-liquid separator. The hybrid refrigerant is separated in the gas-liquid separator. The low-boiling refrigerant becomes gaseous, and the high-boiling refrigerant is liquid. The low-boiling gaseous refrigerant exchanges heat with the high-boiling liquid refrigerant flowing through the throttle valve in the evaporative condenser, so that the temperature of the low-boiling gaseous refrigerant decreases. Then the low-boiling gaseous refrigerant flows through the evaporator to absorb heat from the low-temperature air, thereby increasing the COP value of the heat pump and achieving energy saving. However, in the actual application process, when the hybrid refrigerant cycle heat pump system operates in summer in severely cold regions, the required working temperature difference of the heat pump is much lower than 120°C, resulting in an increase in the external energy required for the phase change of the hybrid refrigerant in the hybrid refrigerant cycle heat pump system, resulting in high energy consumption and poor heating performance of the heat pump system in summer. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of poor heating performance of the hybrid refrigerant cycle heat pump system in the prior art when the working temperature difference is small, so as to provide a hybrid refrigerant heat pump system.

[0005] To solve the above technical problem, the present invention provides a hybrid refrigerant heat pump system, including a compressor, a condenser, a primary gas-liquid separator, an evaporative condenser, and a main evaporator connected to each other;

[0006] It further includes:

[0007] The gas-phase pipeline is connected between the gas-phase output end of the primary gas-liquid separator and the input end of the main evaporator, and the gas-phase pipeline can be set to be open or closed; a liquid storage tank is provided on the gas-phase pipeline, and the evaporation condenser and the liquid storage tank are sequentially arranged on the gas-phase pipeline, and the liquid storage tank is located downstream of the evaporation condenser; a third expansion valve is provided on the gas-phase pipeline;

[0008] The liquid-phase pipeline is connected between the liquid-phase output end of the primary gas-liquid separator and the input end of the main evaporator, and the liquid-phase pipeline can be set to be open or closed; another channel of the evaporation condenser is communicated with the liquid-phase pipeline; a first expansion valve and a second expansion valve are provided on the liquid-phase pipeline, the first expansion valve is located upstream of the evaporation condenser, and the second expansion valve is located downstream of the evaporation condenser;

[0009] The auxiliary reflux pipeline is communicated with one end of the liquid-phase pipeline and is located downstream of the evaporation condenser, and the other end is communicated with the pipeline at the output end of the main evaporator, and the auxiliary reflux pipeline can be set to be open or closed.

[0010] The beneficial effects of the present application compared with the prior art are as follows:

[0011] The hybrid refrigerant heat pump system provided by the present invention, when the hybrid refrigerant heat pump system operates in an environment with a small working temperature difference, the hybrid refrigerant is compressed into a high-temperature and high-pressure gas in the compressor and discharged from the compressor, and then enters the condenser for cooling. At this time, the high-boiling-point refrigerant first condenses into a liquid under the action of the condenser due to its relatively high boiling point, and the low-boiling-point refrigerant cannot condense due to its relatively low boiling point and still exists in the form of a gas. Subsequently, it is separated in the gas-liquid separator. After cooling and liquefaction, the liquid high-boiling-point refrigerant enters the liquid-phase pipeline, expands through the first expansion valve, and then enters the evaporation condenser. After the initial temperature reduction in the evaporation condenser, it enters the main evaporator to absorb heat, and then expands through the second expansion valve and returns to the compressor to complete a cycle. At the same time, the gas-phase pipeline is disconnected, and the low-boiling-point refrigerant gas is output from the gas-phase pipeline, then flows through the evaporation condenser, condenses into a liquid after dissipating heat, and finally enters the liquid storage tank for storage. In the above working process, only the high-boiling-point refrigerant completes the entire cycle, and the low-boiling-point refrigerant gradually flows to the liquid storage tank under the drive of the temperature difference and then terminates the cycle, and finally is stored at the liquid storage tank. When the hybrid refrigerant heat pump system operates in an environment with a large working temperature difference, the hybrid refrigerant is compressed into a high-temperature and high-pressure gas in the compressor and discharged from the compressor, and then enters the condenser for cooling. At this time, the high-boiling-point refrigerant first condenses into a liquid due to its relatively high boiling point, and the low-boiling-point refrigerant cannot condense due to its relatively low boiling point and still exists in the form of a gas. The liquid high-boiling-point refrigerant enters the liquid-phase pipeline, expands through the first expansion valve, and then enters the evaporation condenser to absorb heat, and then directly returns to the compressor through the auxiliary return pipeline. At the same time, the low-boiling-point refrigerant gas enters the evaporation condenser through the gas-phase pipeline, is cooled into a liquid and then enters the liquid storage tank, and then expands through the third expansion valve and enters the main evaporator to absorb heat, and then enters the compressor to complete a cycle. In the above process, the high-boiling-point refrigerant and the low-boiling-point refrigerant jointly complete the entire cycle. The final effect is that the low-boiling-point refrigerant absorbs heat from the main evaporator, and the high-boiling-point refrigerant releases heat to the condenser. By setting the liquid storage tank, when operating in an environment with a small working temperature difference, only the high-boiling-point refrigerant completes the entire cycle, and the low-boiling-point refrigerant gradually flows to the liquid storage tank under the drive of the temperature difference and then terminates the cycle, and finally is stored at the liquid storage tank; when operating in an environment with a large working temperature difference, the high-boiling-point refrigerant and the low-boiling-point refrigerant jointly complete the entire cycle. The final effect is that the low-boiling-point refrigerant absorbs heat from the main evaporator, and the high-boiling-point refrigerant releases heat to the condenser. This enables the hybrid refrigerant heat pump system to maintain a high heating efficiency in both the winter environment with a large working temperature difference and the summer environment with a small working temperature difference, and enables the hybrid refrigerant heat pump system to maintain good heating performance during the annual operation in cold regions, thereby playing a role in energy conservation and emission reduction.

[0012] Optionally, it further includes a first gas-liquid separator and a second gas-liquid separator arranged between the condenser and the evaporation condenser. The first gas-liquid separator includes a first fluid input end, a first liquid-phase output end, and a first gas-phase output end. The first fluid input end and the first liquid-phase output end are both communicated with the liquid-phase pipeline, and the first gas-phase output end is communicated with the gas-phase pipeline;

[0013] The second gas-liquid separator includes a second fluid input end, a second gas-phase output end, and a second liquid-phase output end. The second fluid input end and the second gas-phase output end are both connected to the gas-phase pipeline, and the second liquid-phase output end is connected to the liquid-phase pipeline.

[0014] In the hybrid refrigerant heat pump system provided by the present invention, after the mixed refrigerant passes through the primary gas-liquid separator, the liquid refrigerant with some gaseous refrigerant output from the primary gas-liquid separator enters the first gas-liquid separator from the first fluid input end through the liquid-phase pipeline, and the gaseous refrigerant with some liquid refrigerant enters the second gas-liquid separator from the second fluid input end through the gas-phase pipeline. The liquid high-boiling refrigerant enters the main evaporator after primary separation; most of the low-boiling refrigerant gas and a small part of the high-boiling refrigerant liquid enter the second gas-liquid separator for further separation in the first gas-liquid separator, and the low-boiling refrigerant gas comes out and passes through the evaporation condenser. By performing hierarchical separation on the gas-phase refrigerant and the liquid-phase refrigerant, the gas-liquid separation ability of the system is improved, and the heat exchange ability of the refrigerant is enhanced.

[0015] Optionally, the primary gas-liquid separator includes a separation tank, and the condenser is arranged in the separation tank. The inlet and outlet of the condenser are used to connect to an external heat exchange medium; the separation tank has a total input end connected to the output end of the compressor, a gas-phase output end connected to the gas-phase pipeline, and a liquid-phase output end connected to the liquid-phase pipeline. Optionally, a subcooler is installed on the liquid-phase pipeline between the primary gas-liquid separator and the evaporation condenser. One heat exchange channel of the subcooler is connected to the liquid-phase pipeline, and the other heat exchange channel of the subcooler is used to connect to an external heat exchange medium.

[0016] In the hybrid refrigerant heat pump system provided by the present invention, by arranging the subcooler, the high-boiling refrigerant output from the condenser enters the subcooler. A small amount of low-boiling gas is mixed in a large amount of high-boiling refrigerant liquid. After entering the subcooler, the high-boiling refrigerant is further cooled, so that the high-boiling refrigerant is completely liquefied, the separation ability of the system for the mixed refrigerant is improved, and the heating capacity of the system is enhanced.

[0017] Optionally, one heat exchange channel of the subcooler is connected to the liquid-phase pipeline, and the other heat exchange channel of the subcooler is connected to the condenser.

[0018] Optionally, it further includes a cooling pipeline. One end of the cooling pipeline is connected to the output end of the main evaporator, and the other end is connected to the compressor. The cooling pipeline is provided with an on-off setting, and a regenerator is arranged on the cooling pipeline. One side of the regenerator is connected to the gas-phase pipeline between the evaporation condenser and the liquid storage tank, and the other side is connected to the cooling pipeline between the main evaporator and the compressor.

[0019] The hybrid working fluid heat pump system provided by the present invention is provided with a recuperator. One side of the recuperator is connected to the cooling pipeline, and the other side is connected to the gas pipeline between the evaporative condenser and the liquid storage tank. By setting the recuperator, the working fluid output from the main evaporator absorbs the thermal energy of the working fluid output from the evaporative condenser, so that the working fluid output from the evaporative condenser is further cooled and liquefied, and the working fluid output from the main evaporator is heated and recovered, thereby improving the operating efficiency.

[0020] Optionally, a throttling member is further provided on the cooling pipeline, and the throttling member is located between the main evaporator and the recuperator.

[0021] Optionally, the third expansion valve is located downstream of the liquid storage tank, and a third solenoid valve is provided on the gas pipeline. The third solenoid valve is arranged in parallel with the third expansion valve.

[0022] Optionally, a first solenoid valve is provided on the liquid pipeline, and the first solenoid valve is arranged in parallel with the first expansion valve;

[0023] And / or, a second solenoid valve is provided on the liquid pipeline, and the second solenoid valve is arranged in parallel with the second expansion valve.

[0024] Optionally, a fifth solenoid valve is provided on the gas pipeline, and the fifth solenoid valve is located upstream of the evaporative condenser.

[0025] The hybrid working fluid heat pump system provided by the present invention, through the setting of the above valve group and components, enables the present application to also have an automatic defrosting function. In this defrosting mode, the first solenoid valve and the second solenoid valve are opened, the third solenoid valve, the fourth solenoid valve and the sixth solenoid valve are closed, the fifth solenoid valve is opened first, and is closed after the low-boiling working fluid is stored; the second expansion valve is opened, and the first expansion valve and the third expansion valve are closed.

[0026] The hybrid working fluid is compressed into a high-temperature and high-pressure gas in the compressor and discharged from the compressor, and enters the condenser for cooling. At this time, the high-boiling working fluid condenses into a liquid first because of its higher boiling point, and the low-boiling working fluid cannot condense because of its lower boiling point and still exists in the form of a gas. Thereafter, most of the high-boiling working fluid liquid and a small part of the low-boiling gas enter the subcooler, and the high-boiling working fluid is further cooled. This part of the gas-liquid mixed working fluid then enters the first gas-liquid separator for separation. The liquid high-boiling working fluid passes through the first solenoid valve and the evaporative condenser and then enters the main evaporator for exothermic defrosting, and then flows through the throttling member for throttling. After throttling, the high-boiling working fluid in the low-temperature two-phase state enters the recuperator to absorb heat and become a gas, and then enters the low-pressure side gas-liquid separator, and then enters the compressor from the low-pressure side gas-liquid separator to complete a cycle.

[0027] Meanwhile, most of the low-boiling working fluid gas and a small part of the high-boiling working fluid liquid coming out from the top of the condenser converge with the low-boiling working fluid gas coming out from the first gas-liquid separator, and they jointly enter the second gas-liquid separator for separation. After the low-boiling working fluid gas comes out, it passes through the fifth solenoid valve and the evaporative condenser, and then enters the regenerator where it is cooled into a liquid by the flowing high-boiling low-temperature gas and finally enters the liquid storage tank for storage. At the same time, the high-boiling working fluid liquid coming out from the second gas-liquid separator converges with the high-boiling working fluid liquid coming out from the first gas-liquid separator and participates in the cycle of the aforementioned high-boiling working fluid.

[0028] As described above, only the high-boiling working fluid completes the entire cycle. The low-boiling working fluid gradually flows towards the liquid storage tank under the drive of the temperature difference and then terminates the cycle, and finally is stored here. A large amount of heat is released during the process of cooling and storing the low-boiling working fluid, and this part of the heat is absorbed by the high-boiling working fluid at the regenerator for defrosting, thus realizing the self-defrosting function, which is beneficial to energy saving. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of the hybrid working fluid heat pump system provided in the embodiments of the present invention.

[0031] Description of the reference numerals: 1. Compressor; 2. Condenser; 3. Subcooler; 4. First gas-liquid separator; 5. Second gas-liquid separator; 6. Fifth solenoid valve; 7. First expansion valve; 8. First solenoid valve; 9. Evaporative condenser; 10. Regenerator; 11. Capillary fitting; 12. Fourth solenoid valve; 13. Liquid storage tank; 14. Third solenoid valve; 15. Third expansion valve; 16. Second expansion valve; 17. Second solenoid valve; 18. Main evaporator; 19. Sixth solenoid valve; 20. Low-pressure side gas-liquid separator; 21. Primary gas-liquid separator; 22. Gas-phase pipeline; 23. Liquid-phase pipeline; 24. Auxiliary return pipeline. Detailed Embodiments

[0032] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Figure 1The figure shows a hybrid refrigerant heat pump system provided by this embodiment, which includes a compressor 1, a condenser 2, a primary gas-liquid separator 21, a subcooler 3, a first gas-liquid separator 4, a second gas-liquid separator 5, and a main evaporator 18 that are connected in a cycle. The output end of the main evaporator 18 is connected to the input end of the compressor 1, and a low-pressure side gas-liquid separator 20 is also installed between the output end of the main evaporator 18 and the input end of the compressor 1. In this embodiment, the condenser 2 is built into the separation tank of the primary gas-liquid separator 21. The hybrid refrigerant heat pump system provided by this embodiment further includes a gas phase pipeline 22, a liquid phase pipeline 23, an auxiliary return pipeline 24, a cooling pipeline, an evaporative condenser 9, and a regenerator 10. The gas phase pipeline 22 is connected between the gas phase output end of the primary gas-liquid separator 21 and the input end of the main evaporator 18, and the gas phase pipeline 22 is provided to be openable and closable; a liquid storage tank 13 is arranged on the gas phase pipeline 22, the evaporative condenser 9 and the liquid storage tank 13 are arranged on the gas phase pipeline 22 in sequence, and the liquid storage tank 13 is located downstream of the evaporative condenser 9; a third expansion valve 15 is arranged on the gas phase pipeline 22. The liquid phase pipeline 23 is connected between the liquid phase output end of the primary gas-liquid separator 21 and the input end of the main evaporator 18, and the liquid phase pipeline 23 is provided to be openable and closable; another channel of the evaporative condenser 9 is communicated with the liquid phase pipeline 23; a first expansion valve 7 and a second expansion valve 16 are arranged on the liquid phase pipeline 23, the first expansion valve 7 is located upstream of the evaporative condenser 9, and the second expansion valve 16 is located downstream of the evaporative condenser 9. One end of the auxiliary return pipeline 24 is communicated with the liquid phase pipeline 23 and is located downstream of the evaporative condenser 9, and the other end is communicated with the pipeline of the output end of the main evaporator 18, and the auxiliary return pipeline 24 is provided to be openable and closable. One end of the cooling pipeline is connected to the output end of the main evaporator 18, and the other end is connected to the compressor 1, and the cooling pipeline is provided to be openable and closable. A regenerator 10 is arranged on the cooling pipeline. One side of the regenerator 10 is communicated with the gas phase pipeline 22 between the evaporative condenser 9 and the liquid storage tank 13, and the other side is communicated with the cooling pipeline between the main evaporator 18 and the compressor 1. A capillary tube member 11 serving as a throttling member is also arranged on the cooling pipeline, and the throttling member is located between the main evaporator 18 and the regenerator 10. A fourth solenoid valve 12 is installed in parallel at both ends of the capillary tube member 11. One end of the auxiliary return pipeline 24 is communicated with the liquid phase pipeline 23, and the other end is communicated with the pipeline of the output end of the main evaporator 18.

[0037] The primary gas-liquid separator 21 includes a separation tank, and the condenser 2 is disposed within the separation tank. The separation tank has a total input end connected to the output end of the compressor 1, a gas-phase output end connected to the gas-phase pipeline 22, and a liquid-phase output end connected to the liquid-phase pipeline 23. The inlet and outlet of the condenser 2 are used to connect to an external heat exchange medium pipeline. The subcooler 3 is installed on the liquid-phase pipeline 23 between the primary gas-liquid separator 21 and the evaporative condenser 9. One of the heat exchange channels of the subcooler 3 communicates with the liquid-phase pipeline 23, and the other heat exchange channel of the subcooler 3 communicates with the condenser 2 for connecting to an external heat exchange medium. The liquid-phase pipeline 23 is connected to the heat supply side of the subcooler 3, and a water supply pipeline is connected to the heat extraction side of the subcooler 3. The water supply pipeline enters the heat extraction side of the condenser 2 after passing through the heat extraction side of the subcooler 3, extracts heat from the heat release side of the condenser 2, so that the heat in the mixed refrigerant passing through the heat release side of the condenser 2 is transferred to the water in the water supply pipeline, so as to provide hot water for the external heat exchange medium pipeline through the water supply pipeline.

[0038] The first gas-liquid separator 4 and the second gas-liquid separator 5 are disposed between the condenser 2 and the evaporative condenser 9. The first gas-liquid separator 4 includes a first fluid input end, a first liquid-phase output end, and a first gas-phase output end. The first fluid input end and the first liquid-phase output end are both connected to the liquid-phase pipeline 23, and the first gas-phase output end is connected to the gas-phase pipeline 22. The second gas-liquid separator 5 includes a second fluid input end, a second gas-phase output end, and a second liquid-phase output end. The second fluid input end and the second gas-phase output end are both connected to the gas-phase pipeline 22, and the second liquid-phase output end is connected to the liquid-phase pipeline 23. In this embodiment, the low-boiling refrigerant gas output from the gas-phase outlet of the primary gas-liquid separator 21 directly enters the input end of the second gas-liquid separator 5. Most of the high-boiling refrigerant liquid and a small amount of low-boiling gas output from the liquid-phase outlet of the primary gas-liquid separator 21 enter the subcooler 3. The high-boiling refrigerant is further cooled. The mixed refrigerant in this gas-liquid mixed state then enters the first gas-liquid separator 4 for separation. The liquid high-boiling refrigerant is directly output, and the separated gaseous refrigerant enters the second gas-liquid separator 5. A first solenoid valve 8 and a first expansion valve 7 are installed in parallel on the liquid-phase pipeline 23 upstream of the evaporative condenser 9. A second solenoid valve 17 and a second expansion valve 16 are installed in parallel on the liquid-phase pipeline 23 downstream of the evaporative condenser 9. A third solenoid valve 14 and a third expansion valve 15 are installed on the gas-phase pipeline 22 downstream of the accumulator 13. A fifth solenoid valve 6 is installed at the second gas-phase output end of the second gas-liquid separator 5, and a sixth solenoid valve 19 is installed on the auxiliary return pipeline 24.

[0039] The hybrid refrigerant heat pump system provided in this embodiment operates in a single refrigerant cycle under low temperature difference conditions. In this cycle mode, the first solenoid valve 8 and the fourth solenoid valve 12 are opened, the second solenoid valve 17, the third solenoid valve 14, and the sixth solenoid valve 19 are closed, and the fifth solenoid valve 6 is opened first and then closed after the low-boiling refrigerant is stored; the second expansion valve 16 is opened, and the first expansion valve 7 and the third expansion valve 15 are closed. This process is realized by a single refrigerant cycle, which can achieve efficient and stable operation under low pressure difference conditions such as startup, high ambient temperature, or low water temperature.

[0040] The hybrid refrigerant is compressed into a high-temperature and high-pressure gas in the compressor 1 and discharged from the compressor 1, and then enters the primary gas-liquid separator 21 for cooling. At this time, the high-boiling refrigerant first condenses into a liquid under the action of the condenser 2 due to its higher boiling point, while the low-boiling refrigerant cannot condense due to its lower boiling point and remains in a gaseous state. Then, most of the high-boiling refrigerant liquid and a small amount of low-boiling gas enter the subcooler 3, and the high-boiling refrigerant is further cooled. This part of the gas-liquid mixture of the hybrid refrigerant then enters the first gas-liquid separator 4 for separation. The liquid high-boiling refrigerant passes through the first solenoid valve 8 and the evaporative condenser 9 and then throttles at the second expansion valve 16, and then enters the main evaporator 18 to absorb heat. Subsequently, it enters the low-pressure side gas-liquid separator 20 through the regenerator 10 and then enters the compressor 1 from the low-pressure side gas-liquid separator 20 to complete a cycle.

[0041] At the same time, most of the low-boiling refrigerant gas and a small amount of high-boiling refrigerant liquid coming out of the top of the primary gas-liquid separator 21 converge with the low-boiling refrigerant gas coming out of the first gas-liquid separator 4 and jointly enter the second gas-liquid separator 5 for separation. After the low-boiling refrigerant gas comes out, it passes through the fifth solenoid valve 6 and the evaporative condenser 9, and then enters the regenerator 10 and is cooled into a liquid by the high-boiling low-temperature gas flowing through it and finally enters the liquid storage tank 13 for storage. At the same time, the high-boiling refrigerant liquid coming out of the second gas-liquid separator 5 converges with the high-boiling refrigerant liquid coming out of the first gas-liquid separator 4 and participates in the above-mentioned cycle of the high-boiling refrigerant.

[0042] Only the high-boiling refrigerant completes the entire cycle as described above, and the low-boiling refrigerant gradually flows to the liquid storage tank 13 under the drive of the temperature difference and then terminates the cycle and is finally stored here.

[0043] The hybrid refrigerant heat pump system provided in this embodiment operates in a hybrid refrigerant cycle under high temperature difference conditions. In this cycle mode, the fourth solenoid valve 12, the fifth solenoid valve 6, and the sixth solenoid valve 19 are opened, and the first solenoid valve 8, the second solenoid valve 17, and the third solenoid valve 14 are closed; the first expansion valve 7 and the third expansion valve 15 are opened, and the second expansion valve 16 is closed.

[0044] The mixed refrigerant is compressed into a high-temperature and high-pressure gas in the compressor 1 and discharged from the compressor 1, and then enters the primary gas-liquid separator 21 for cooling. At this time, the high-boiling refrigerant condenses into a liquid first due to its higher boiling point, while the low-boiling refrigerant cannot condense due to its lower boiling point and remains in the gas form. After that, most of the high-boiling refrigerant liquid and a small part of the low-boiling gas enter the subcooler 3, and the high-boiling refrigerant is further cooled. The gas-liquid mixed refrigerant in this part then enters the first gas-liquid separator 4 for separation. The liquid high-boiling refrigerant becomes a low-temperature two-phase state after throttling through the first expansion valve 7 and enters the evaporative condenser 9 to absorb heat, and then enters the low-pressure side gas-liquid separator 20 after passing through the sixth solenoid valve 19, and then enters the compressor 1 from the low-pressure side gas-liquid separator 20.

[0045] At the same time, most of the low-boiling refrigerant gas and a small part of the high-boiling refrigerant liquid coming out from the top of the primary gas-liquid separator 21 are combined with the low-boiling refrigerant gas coming out from the first gas-liquid separator 4 and enter the second gas-liquid separator 5 for separation together. After the low-boiling refrigerant gas comes out, it enters the evaporative condenser 9 and the regenerator 10 in sequence through the fifth solenoid valve 6 and is cooled into a liquid by the high-boiling low-temperature gas and the low-boiling low-temperature gas flowing through respectively, and then enters the liquid receiver 13. Subsequently, it enters the main evaporator 18 to absorb heat after throttling through the third expansion valve 15, and after coming out, it enters the regenerator 10 to absorb the heat of the low-boiling refrigerant and is combined with the high-boiling refrigerant low-temperature gas coming out from the sixth solenoid valve 19 and then enters the gas separator together, and finally enters the compressor 1 to complete a cycle. At the same time, the high-boiling refrigerant liquid coming out from the second gas-liquid separator 5 is combined with the high-boiling refrigerant liquid coming out from the first gas-liquid separator 4 and participates in the cycle of the above-mentioned high-boiling refrigerant.

[0046] As described above, the high-boiling refrigerant and the low-boiling refrigerant jointly complete the whole cycle. The final effect is that the low-boiling refrigerant absorbs heat from the evaporator, and the high-boiling refrigerant releases heat to the condenser 2.

[0047] When the defrosting cycle of the mixed refrigerant heat pump system provided in this embodiment works, the first solenoid valve 8 and the second solenoid valve 17 are opened in this cycle mode, the third solenoid valve 14, the fourth solenoid valve 12 and the sixth solenoid valve 19 are closed, the fifth solenoid valve 6 is opened first and closed after the low-boiling refrigerant is stored; the second expansion valve 16 is opened, and the first expansion valve 7 and the third expansion valve 15 are closed.

[0048] The mixed refrigerant is compressed into a high-temperature and high-pressure gas in the compressor 1 and discharged from the compressor 1, then enters the primary gas-liquid separator 21 for cooling. At this time, the high-boiling refrigerant condenses into a liquid first due to its higher boiling point, while the low-boiling refrigerant cannot condense due to its lower boiling point and remains in the gas form. Thereafter, most of the high-boiling refrigerant liquid and a small part of the low-boiling gas enter the subcooler 3, and the high-boiling refrigerant is further cooled. This part of the gas-liquid mixed refrigerant then enters the first gas-liquid separator 4 for separation. The liquid high-boiling refrigerant passes through the first solenoid valve 8 and the evaporative condenser 9 and then enters the main evaporator 18 for exothermic defrosting. Subsequently, it flows through the capillary tube 11 for throttling. After throttling, the high-boiling refrigerant in the low-temperature two-phase state enters the regenerator 10 to absorb heat and turn into a gas, then enters the low-pressure side gas-liquid separator 20, and then enters the compressor 1 from the low-pressure side gas-liquid separator 20 to complete a cycle.

[0049] Meanwhile, most of the low-boiling refrigerant gas and a small part of the high-boiling refrigerant liquid coming out from the top of the primary gas-liquid separator 21 converge with the low-boiling refrigerant gas coming out from the first gas-liquid separator 4 and jointly enter the second gas-liquid separator 5 for separation. After the low-boiling refrigerant gas comes out, it passes through the fifth solenoid valve 6 and the evaporative condenser 9, and then enters the regenerator 10 where it is cooled into a liquid by the flowing high-boiling low-temperature gas and finally enters the liquid storage tank 13 for storage. At the same time, the high-boiling refrigerant liquid coming out from the second gas-liquid separator 5 converges with the high-boiling refrigerant liquid coming out from the first gas-liquid separator 4 and participates in the cycle of the aforementioned high-boiling refrigerant.

[0050] As described above, only the high-boiling refrigerant completes the entire cycle. The low-boiling refrigerant gradually flows to the liquid storage tank 13 under the drive of the temperature difference and then terminates the cycle, and finally is stored here. A large amount of heat is released during the process of cooling and storing the low-boiling refrigerant, and this part of the heat is absorbed by the high-boiling refrigerant at the regenerator 10 for defrosting.

[0051] The mixed-refrigerant heat pump system provided in this embodiment can realize the adaptive automatic switching of the single-refrigerant cycle, the mixed-refrigerant cycle, and the defrosting cycle, and can meet the heating demand at -45°C at the lowest, meeting the heating needs in severe cold regions; at the same time, it can ensure double-high efficiency operation under high-pressure difference and low-pressure difference conditions and defrosting reliability. By selecting a suitable refrigerant combination, the pressure corresponding to the temperature at which the low-boiling refrigerant exchanges heat with the -45°C air meets the compression requirements of the compressor 1, and heat absorption at -45°C can be realized for heating. In extremely cold weather, the mixed-refrigerant cycle is turned on, the low-boiling refrigerant absorbs heat from the ultra-low temperature air and transfers it to the high-boiling refrigerant, and the high-boiling refrigerant releases heat to the water that needs to be heated. This system can not only meet the heating needs in extreme weather, but also because the high- and low-boiling refrigerants each play their own characteristics, the system pressure ratio can be lower than that of a conventional heat pump system, and the heating efficiency is higher.

[0052] The hybrid refrigerant heat pump system provided in this embodiment can operate efficiently under both high temperature difference and low temperature difference conditions. Whether in severe cold regions or cold regions, affected by factors such as seasonal climate change, daily temperature change, and user water temperature change, the working temperature difference of the heat pump varies within a large range during operation. In the actual operation process, the high temperature difference and low temperature difference conditions alternate with each other. This system can enable the heat pump to automatically switch the operating cycle according to the temperature difference change, achieving efficient and stable operation under all conditions.

[0053] The hybrid refrigerant heat pump system provided in this embodiment does not require reverse stable defrosting and can achieve continuous heating during the defrosting process. Currently, defrosting in the industry is mainly achieved through reverse circulation. During the defrosting process, the water temperature fluctuates greatly, and the user comfort is greatly affected. This system makes full use of the characteristics of the hybrid refrigerant. During the defrosting process, the condensation heat release of the low-boiling refrigerant is collected, and this part of the heat is absorbed by the high-boiling refrigerant for defrosting. The whole process does not require reverse, and the heat pump can achieve continuous heating, improving user comfort.

[0054] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A hybrid working fluid heat pump system, characterized in that, It includes a connected compressor (1), a condenser (2), a primary gas-liquid separator (21), an evaporative condenser (9), and a main evaporator (18); It further includes: A gas-phase pipeline (22) is connected between the gas-phase output end of the primary gas-liquid separator (21) and the input end of the main evaporator (18), and the gas-phase pipeline (22) is provided with an on-off setting; a liquid storage device (13) is arranged on the gas-phase pipeline (22), the evaporative condenser (9) and the liquid storage device (13) are arranged on the gas-phase pipeline (22) in sequence, and the liquid storage device (13) is located downstream of the evaporative condenser (9); a third expansion valve (15) is arranged on the gas-phase pipeline (22); A liquid-phase pipeline (23) is connected between the liquid-phase output end of the primary gas-liquid separator (21) and the input end of the main evaporator (18), and the liquid-phase pipeline (23) is provided with an on-off setting; another channel of the evaporative condenser (9) is communicated with the liquid-phase pipeline (23); a first expansion valve (7) and a second expansion valve (16) are arranged on the liquid-phase pipeline (23), the first expansion valve (7) is located upstream of the evaporative condenser (9), and the second expansion valve (16) is located downstream of the evaporative condenser (9); An auxiliary reflux pipeline (24) has one end communicated with the liquid-phase pipeline (23) and located downstream of the evaporative condenser (9), and the other end is communicated with the output pipeline of the main evaporator (18), and the auxiliary reflux pipeline (24) is provided with an on-off setting.

2. The hybrid working medium heat pump system according to claim 1, characterized in that It further includes a first gas-liquid separator (4) and a second gas-liquid separator (5) arranged between the condenser and the evaporative condenser (9); The first gas-liquid separator (4) includes a first fluid input end, a first liquid-phase output end, and a first gas-phase output end. The first fluid input end and the first liquid-phase output end are both communicated with the liquid-phase pipeline (23), and the first gas-phase output end is communicated with the gas-phase pipeline (22); The second gas-liquid separator (5) includes a second fluid input end, a second gas-phase output end, and a second liquid-phase output end. The second fluid input end and the second gas-phase output end are both communicated with the gas-phase pipeline (22), and the second liquid-phase output end is communicated with the liquid-phase pipeline (23).

3. The hybrid working medium heat pump system according to claim 2, wherein The primary gas-liquid separator (21) includes a separation box, the condenser (2) is arranged in the separation box, and the inlet and outlet of the condenser (2) are used to connect external heat exchange media; the separation box has a total input end connected to the output end of the compressor (1), a gas-phase output end connected to the gas-phase pipeline (22), and a liquid-phase output end connected to the liquid-phase pipeline (23).

4. The hybrid working fluid heat pump system according to any one of claims 1 to 3, characterized in that, An undercooler (3) is installed on the liquid-phase pipeline (23) between the primary gas-liquid separator (21) and the evaporative condenser (9). One heat exchange channel of the undercooler (3) is communicated with the liquid-phase pipeline (23), and the other heat exchange channel of the undercooler (3) is used to connect external heat exchange media.

5. The hybrid working fluid heat pump system according to claim 4, wherein, One of the heat exchange channels of the subcooler (3) is communicated with the liquid phase pipeline (23), and the other heat exchange channel of the subcooler (3) is communicated with the condenser (2).

6. The hybrid working fluid heat pump system according to any one of claims 1 to 3, characterized in that It further includes a cooling pipeline. One end of the cooling pipeline is connected to the output end of the main evaporator (18), and the other end is connected to the compressor (1). The cooling pipeline is provided with an on-off setting, and a regenerator (10) is arranged on the cooling pipeline. One side of the regenerator (10) is communicated with the gas phase pipeline (22) between the evaporative condenser (9) and the liquid storage tank (13), and the other side is communicated with the cooling pipeline between the main evaporator (18) and the compressor (1).

7. The hybrid working fluid heat pump system according to claim 6, wherein, A throttling element is further arranged on the cooling pipeline, and the throttling element is located between the main evaporator (18) and the regenerator (10).

8. The hybrid working medium heat pump system according to any one of claims 1 to 3, characterized in that, The third expansion valve (15) is located downstream of the liquid storage tank (13), and a third solenoid valve (14) is arranged on the gas phase pipeline. The third solenoid valve (14) is arranged in parallel with the third expansion valve (15).

9. The hybrid refrigerant heat pump system according to any one of claims 1 to 3, characterized in that A first solenoid valve (8) is arranged on the liquid phase pipeline (23), and the first solenoid valve (8) is arranged in parallel with the first expansion valve (7); And / or, a second solenoid valve (17) is arranged on the liquid phase pipeline (23), and the second solenoid valve (17) is arranged in parallel with the second expansion valve (16).

10. The hybrid working medium heat pump system according to any one of claims 1 to 3, characterized in that, A fifth solenoid valve (6) is arranged on the gas phase pipeline (22), and the fifth solenoid valve (6) is located upstream of the evaporative condenser (9).

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