Intermediate refrigerant subcooling carbon dioxide air conditioning system

Abstract

The present invention relates to the technical field of air conditioning systems and discloses an intermediate refrigerant subcooled carbon dioxide air conditioning system, comprising: a carbon dioxide compressor, an oil separator, an indoor unit, a primary electronic expansion valve, a regenerator, a gas-liquid separator, a liquid storage tank, a secondary electronic expansion valve, an outdoor unit, and a subcooling system. The subcooling system is connected to a heating and refrigeration cycle to cool the carbon dioxide refrigerant flowing from the indoor and outdoor units into a first heat regeneration flow path of the regenerator. The present invention solves the problem in existing carbon dioxide air conditioning systems of poor cooling and heating performance and high energy consumption due to the low cooling efficiency of the carbon dioxide refrigerant.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning systems, and in particular to an intermediate refrigerant supercooling carbon dioxide air-conditioning system. Background Art

[0002] CO2 air conditioning systems use carbon dioxide as a refrigerant. Carbon dioxide is a rare natural refrigerant that is non-toxic, non-flammable, inexpensive, readily available, and environmentally friendly, offering significant advantages as a refrigerant. While maintaining a high COP (cost-effective performance), CO2 air conditioning offers excellent environmental performance. It can effectively control ozone depletion, reduce greenhouse gas production, inhibit coal combustion, lower the incidence of smog, and reduce PM2.5 concentrations. By seamlessly integrating energy conservation and environmental protection, CO2 air conditioning has a broad market and potential in my country.

[0003] However, in existing carbon dioxide air conditioning systems, due to the low cooling degree of carbon dioxide refrigerant, the carbon dioxide air conditioning system often suffers from poor cooling and heating effects and high energy consumption. Summary of the Invention

[0004] Based on the above technical problems, the present invention provides an intermediate refrigerant supercooling carbon dioxide air-conditioning system, which solves the problem that the existing carbon dioxide air-conditioning system often has poor cooling and heating effects and high energy consumption due to the low cooling degree of the carbon dioxide refrigerant.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] An intermediate refrigerant subcooling carbon dioxide air-conditioning system includes: a carbon dioxide compressor, an oil separator, an indoor unit, a primary electronic expansion valve, a regenerator, a gas-liquid separator, a liquid storage tank, a secondary electronic expansion valve, an outdoor unit and a subcooling system; the exhaust port of the carbon dioxide compressor is connected to the oil separator, the indoor unit, the primary electronic expansion valve, the first heat recovery flow path of the regenerator, the liquid storage tank, the secondary electronic expansion valve, the outdoor unit, the second heat recovery flow path of the regenerator, and the gas-liquid separator in sequence through a pipeline, and then returns to the intake port of the carbon dioxide compressor, forming a heating cycle loop; the exhaust port of the carbon dioxide compressor is connected to the oil separator, the outdoor unit, the primary electronic expansion valve, the first heat recovery flow path of the regenerator, the liquid storage tank, the secondary electronic expansion valve, the indoor unit, the second heat recovery flow path of the regenerator, and the gas-liquid separator in sequence through a pipeline, and then returns to the intake port of the carbon dioxide compressor, forming a refrigeration cycle loop; the subcooling system is connected to the heating cycle loop and the refrigeration cycle loop to cool the carbon dioxide refrigerant flowing into the first heat recovery flow path of the regenerator from the indoor unit and the outdoor unit.

[0007] Furthermore, the subcooling system includes a subcooling compressor, a subcooling electronic expansion valve, an intermediate subcooling heat exchanger, a subcooling liquid storage tank, and a subcooling gas-liquid separator. One end of the first heat exchange channel of the intermediate subcooling heat exchanger is connected to the indoor unit and the outdoor unit respectively, and the other end is connected to the first heat recovery channel of the regenerator; the exhaust port of the subcooling compressor is connected to the indoor unit, the subcooling liquid storage tank, the subcooling electronic expansion valve, the second heat exchange channel of the intermediate subcooling heat exchanger, and the subcooling gas-liquid separator in sequence through a pipeline and then returns to the air intake of the subcooling compressor, forming a heating subcooling circuit; the exhaust port of the subcooling compressor is connected to the outdoor unit, the subcooling liquid storage tank, the subcooling electronic expansion valve, the second heat exchange channel of the intermediate subcooling heat exchanger, and the subcooling gas-liquid separator in sequence through a pipeline and then returns to the air intake of the subcooling compressor, forming a cooling subcooling circuit.

[0008] Furthermore, the subcooling compressor is provided with a control device and a frequency converter.

[0009] Furthermore, a filter is provided at the liquid outlet of the supercooling liquid storage tank.

[0010] Furthermore, a high-pressure safety device is provided at the exhaust port end of the subcooling compressor, and a low-pressure safety device is provided at the inlet end of the subcooling gas-liquid separator.

[0011] Furthermore, a sight glass is provided at the liquid outlet end of the supercooling liquid storage tank.

[0012] Furthermore, a high-pressure safety device is provided at the exhaust port of the carbon dioxide compressor, and a low-pressure safety device is provided at the inlet port of the gas-liquid separator.

[0013] Furthermore, filters are provided at the outlet end of the gas-liquid separator and the liquid outlet end of the liquid storage tank.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention incorporates a subcooling system that cools the CO2 refrigerant flowing from the indoor and outdoor units to the regenerator during the CO2 air conditioning system's cooling or heating process, thereby increasing the CO2 refrigerant's cooling efficiency. This solves the problem of existing CO2 air conditioning systems often suffering from poor cooling and heating performance and high energy consumption due to the low cooling efficiency of the CO2 refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present application will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a structural diagram of the intermediate refrigerant supercooling carbon dioxide air-conditioning system.

[0018] Among them, 1 carbon dioxide compressor, 2 four-way valve, 3 indoor unit, 4 outdoor unit, 5 oil separator, 6 gas-liquid separator, 7 regenerator, 8 liquid storage tank, 9 secondary electronic expansion valve, 10 one-way valve, 11 solenoid valve, 12 filter, 13 high-pressure safety device, 14 low-pressure safety device, 15 subcooling compressor, 16 subcooling gas-liquid separator, 17 primary electronic expansion valve, 18 intermediate subcooling heat exchanger, 19 subcooling electronic expansion valve, 20 sight glass, 21 subcooling liquid storage tank, 22 control device, 23 inverter, 24 solenoid valve. DETAILED DESCRIPTION

[0019] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0020] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0021] Figure 1 The following is a schematic diagram of the structure of an intermediate refrigerant subcooling carbon dioxide air conditioning system illustrated in some embodiments of the present application. The following describes the intermediate refrigerant subcooling carbon dioxide air conditioning system involved in the present application in conjunction with the diagram. It should be noted that the diagram is merely an example and does not limit the specific shape and structure of the intermediate refrigerant subcooling carbon dioxide air conditioning system.

[0022] See Figure 1In some embodiments, the intermediate refrigerant subcooling carbon dioxide air-conditioning system includes: a carbon dioxide compressor 1, an oil separator 5, an indoor unit 3, a primary electronic expansion valve 17, a regenerator 7, a gas-liquid separator 6, a liquid storage tank 8, a secondary electronic expansion valve 9, an outdoor unit 4 and a subcooling system; the exhaust port of the carbon dioxide compressor 1 is connected to the oil separator 5, the indoor unit 3, the primary electronic expansion valve 17, the first heat recovery flow path of the regenerator 7, the liquid storage tank 8, the secondary electronic expansion valve 9, the outdoor unit 4, the second heat recovery flow path of the regenerator 7, the gas-liquid separator 6 in sequence through a pipeline and then returns to the air intake port of the carbon dioxide compressor 1, forming A heating cycle is formed; the exhaust port of the carbon dioxide compressor 1 is connected to the oil separator 5, the outdoor unit 4, the primary electronic expansion valve 17, the first heat recovery flow channel of the regenerator 7, the liquid storage tank 8, the secondary electronic expansion valve 9, the indoor unit 3, the second heat recovery flow channel of the regenerator 7, the gas-liquid separator 6 in sequence through a pipeline and then returns to the intake port of the carbon dioxide compressor 1 to form a refrigeration cycle; one end of the subcooling system is connected to the indoor unit 3 and the outdoor unit 4 respectively, and the other end is connected to the first heat recovery flow channel of the regenerator 7; the subcooling system is used to cool the carbon dioxide refrigerant flowing from the indoor unit 3 and the outdoor unit 4 to the regenerator 7.

[0023] Preferably, a high-pressure safety device 13 is provided at the exhaust port of the CO2 compressor 1, and a low-pressure safety device 14 is provided at the inlet port of the gas-liquid separator 6. The high-pressure safety device 13 monitors the pressure at the exhaust port of the CO2 compressor 1, and the low-pressure safety device 14 monitors the pressure at the inlet port of the gas-liquid separator 6, to ensure the safety of the CO2 air conditioning system.

[0024] Preferably, a filter 12 is provided at the outlet of the gas-liquid separator 6 and the liquid outlet of the liquid storage tank 8. The filter 12 can filter the gaseous carbon dioxide refrigerant discharged from the gas-liquid separator 6 to prevent impurities from entering the carbon dioxide compressor 1 and affecting the operation of the carbon dioxide compressor 1. The filter 12 can also filter the liquid refrigerant flowing out of the liquid storage tank 8 to prevent impurities contained therein from clogging the outdoor unit 4 or the indoor unit 3.

[0025] In addition, from Figure 1 From the structures of the heating cycle circuit and the refrigeration cycle circuit, it can be found that there are overlapping parts between the heating cycle circuit and the refrigeration cycle circuit, for example: the primary electronic expansion valve 17, the first heat recovery flow channel of the regenerator 7, and part of the pipeline of the liquid storage tank 8; the second heat recovery flow channel of the regenerator 7, the gas-liquid separator 6, the carbon dioxide compressor 1, and part of the pipeline of the oil separator 5.

[0026] Therefore, to reduce piping costs, the overlapping portions of the heating and cooling circuits can share common piping. Valves are installed in the overlapping and separated portions to control the flow of the CO2 refrigerant. For example, solenoid valves 24 (A1, A2) and a check valve 10 are installed on the pipes connecting the liquid storage tank 8 to the indoor and outdoor units 3 and 4, respectively. A four-way valve 2 is installed at the junctions between the oil separator 5, the indoor unit 3, the outdoor unit 4, and the regenerator 7. A check valve 10 is installed at the first regenerative pipe connecting the indoor and outdoor units 3 and 4 to the regenerator 7.

[0027] In some embodiments, the subcooling system includes a subcooling compressor 15, a subcooling electronic expansion valve 19, an intermediate subcooling heat exchanger 18, a subcooling liquid storage tank 21, and a subcooling gas-liquid separator 16. One end of the first heat exchange channel of the intermediate subcooling heat exchanger 18 is connected to the indoor unit 3 and the outdoor unit 4 respectively, and the other end is connected to the first heat recovery channel of the regenerator 7; the exhaust port of the subcooling compressor 15 is connected to the indoor unit 3, the subcooling liquid storage tank 21, the subcooling electronic expansion valve 19, the second heat exchange channel of the intermediate subcooling heat exchanger 18, and the subcooling gas-liquid separator 16 in sequence through a pipeline, and then returns to the air intake of the subcooling compressor 15, forming a heating subcooling circuit; the exhaust port of the subcooling compressor 15 is connected to the outdoor unit 4, the subcooling liquid storage tank 21, the subcooling electronic expansion valve 19, the second heat exchange channel of the intermediate subcooling heat exchanger 18, and the subcooling gas-liquid separator 16 in sequence through a pipeline, and then returns to the air intake of the subcooling compressor 15, forming a cooling subcooling circuit.

[0028] Preferably, the subcooling compressor 15 is provided with a control device 22 and a frequency converter 23. The frequency converter 23 can use the control device 22 to adjust the subcooling compressor 15 according to the operating conditions of the carbon dioxide air conditioning system to achieve the effect of reducing energy consumption.

[0029] Preferably, a filter 12 is provided at the liquid outlet of the subcooling liquid storage tank 21. The filter 12 can filter the liquid refrigerant flowing out of the subcooling liquid storage tank 21 to prevent the impurities contained therein from clogging the intermediate subcooling heat exchanger 18.

[0030] Preferably, a high-pressure safety device 13 is provided at the exhaust port of the subcooling compressor 15, and a low-pressure safety device 14 is provided at the inlet port of the subcooling gas-liquid separator 16. The high-pressure safety device 13 monitors the pressure at the exhaust port of the subcooling compressor 15, and the low-pressure safety device 14 monitors the pressure at the inlet port of the subcooling gas-liquid separator 16, to ensure the safety of the subcooling system operation.

[0031] Preferably, a sight glass 20 is provided at the liquid outlet end of the supercooling liquid storage tank 21. The sight glass 20 can be used to check the liquid carbon dioxide refrigerant in the supercooling liquid storage tank 21.

[0032] In addition, from Figure 1It can be found from the structures of the heating subcooling circuit and the refrigeration subcooling circuit that there are overlapping parts between the heating subcooling circuit and the refrigeration subcooling circuit, such as: the subcooling liquid storage tank 21, the subcooling electronic expansion valve 19, the second heat exchange channel of the intermediate subcooling heat exchanger 18, the subcooling gas-liquid separator 16, and part of the pipeline of the subcooling compressor 15.

[0033] Therefore, to reduce piping costs, the overlapping portions of the heating and cooling circuits can share common piping. Valves are installed in the overlapping and separated portions to control the flow of the subcooled refrigerant. For example, solenoid valves 24 (B1, B2, B3, B4) and a check valve 10 are installed on the pipes connecting the subcooling compressor 15 to the indoor and outdoor units 3 and 4, respectively. Solenoid valves 24 are also installed where the indoor and outdoor units 3 and 4 connect to the subcooling liquid storage tank 21.

[0034] The heating and cooling working processes of the intermediate refrigerant supercooling carbon dioxide air conditioner in this application are described in combination with the above embodiments:

[0035] Heating process: CO2 compressor 1 compresses the CO2 refrigerant into a high-temperature, high-pressure gas that enters the oil separator 5. The oil separator 5 separates the lubricating oil carried out of the compressor from the refrigerant and replenishes it back to the compressor via the oil return pipe. The high-temperature, high-pressure gas passes through the four-way valve 2 and enters the indoor unit 3 for cooling and dissipation, heating the ambient temperature. The refrigerant flowing through the indoor unit 3 is cooled to a medium-temperature, medium-pressure gas-liquid mixture. It passes through a one-way valve 10 (solenoid valve A1 is closed and solenoid valve A2 is open during heating) and is sprayed through a primary electronic expansion valve 17 to the intermediate subcooling heat exchanger 18 for cooling. It then reaches the regenerator 7 for further cooling. The cooled refrigerant then enters the liquid storage tank 8 for storage. Part of the liquid refrigerant is filtered through the filter 12 and then enters the secondary electronic expansion valve 9. The electronic expansion valve controls the liquid spraying and enters the outdoor unit 4 for evaporation. The evaporated refrigerant becomes a low-temperature, low-pressure gas and enters the regenerator 7 through the four-way valve 2 to cool the medium-temperature part of the refrigerant. After overheating, it returns to the gas-liquid separator 6. The separated low-temperature, low-pressure dry vapor is filtered through the filter 12 and then returns to the compressor intake port to complete the heating cycle.

[0036] The subcooling compressor 15 runs simultaneously with the main heating system, compressing the refrigerant into a high-temperature and high-pressure gas, passing through the one-way valve 10 and the solenoid valve 24 (solenoid valves B1 and B4 are open during heating, and solenoid valves B2 and B3 are closed) to enter the indoor unit 3 for cooling and heat dissipation, providing auxiliary heating to the environment. The refrigerant flowing through the indoor unit 3 is cooled to a gas-liquid mixture of medium temperature and medium pressure, and reaches the subcooling liquid storage tank 21 for liquid storage through the solenoid valve 24. Part of the liquid refrigerant is filtered through the filter 12 and then controlled by the cold electronic expansion valve 19 to enter the intermediate subcooling heat exchanger 18 to cool the main carbon dioxide refrigerant. The subcooled refrigerant returns to the subcooling gas-liquid separator 16, and after gas-liquid separation, the low-temperature gas refrigerant returns to the intake port of the subcooling compressor 15 to complete the subcooling cycle.

[0037] Refrigeration process: The CO2 compressor 1 compresses the CO2 refrigerant into a high-temperature, high-pressure gas that enters the oil separator 5. The oil separator 5 separates the lubricating oil carried out of the compressor from the refrigerant and replenishes it back to the compressor through the oil return pipe. The high-temperature, high-pressure gas is diverted through the four-way valve 2 and enters the outdoor unit 4 for cooling and dissipation. The refrigerant passing through the outdoor unit 4 is cooled to a medium-temperature, medium-pressure gas-liquid mixture. It passes through the one-way valve 10 (solenoid valve A2 is closed and solenoid valve A1 is open during cooling) and is sprayed through the primary electronic expansion valve 17 to the intermediate subcooling heat exchanger 18 for cooling. It then reaches the regenerator 7 for further cooling. The cooled refrigerant enters the liquid storage tank 8 for storage. Part of the liquid refrigerant is filtered through the filter 12 and enters the secondary electronic expansion valve 9. The electronic expansion valve controls the spraying of the liquid into the indoor unit 3 for evaporation. The evaporation absorbs heat and lowers the ambient temperature. The evaporated refrigerant becomes a low-temperature, low-pressure gas, which is diverted through the four-way valve 2 and enters the regenerator 7 to cool the medium-temperature part of the refrigerant. After cooling, it returns to the gas-liquid separator 6. The separated low-temperature, low-pressure gas is filtered through the filter 12 and returns to the compressor intake port to complete the refrigeration cycle.

[0038] The subcooling compressor 15 runs simultaneously with the main refrigeration system, compressing the refrigerant into a high-temperature and high-pressure gas, which passes through the one-way valve 10 and the solenoid valve 24 (the solenoid valves B1 and B4 are closed during cooling, and the solenoid valves B2 and B3 are open) to enter the outdoor unit 4 for cooling and heat dissipation. The refrigerant flowing through the outdoor unit 4 is cooled to a gas-liquid mixture of medium temperature and medium pressure, and passes through the solenoid valve 24 to reach the subcooling liquid storage tank 21 for liquid storage. Part of the liquid refrigerant is filtered through the filter 12 and then controlled by the cold electronic expansion valve 19 to enter the intermediate subcooling heat exchanger 18 to cool the main carbon dioxide refrigerant. The subcooled refrigerant returns to the subcooling system gas-liquid separator 6. After gas-liquid separation, the low-temperature gas refrigerant returns to the intake port of the subcooling compressor 15 to complete the subcooling cycle.

[0039] The above are embodiments of the present invention. The above embodiments and the specific parameters therein are only for the purpose of clearly describing the verification process of the invention and are not intended to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention shall still be subject to the claims. Any equivalent structural changes made by using the contents of the description and drawings of the present invention shall be included in the scope of protection of the present invention.

Claims

1. Intermediate refrigerant supercooling carbon dioxide air conditioning system, characterized in that: include: CO2 compressor, oil separator, indoor unit, primary electronic expansion valve, regenerator, gas-liquid separator, liquid storage tank, secondary electronic expansion valve, outdoor unit and subcooling system; The exhaust port of the carbon dioxide compressor is connected to the oil separator, the indoor unit, the primary electronic expansion valve, the first heat recovery flow channel of the regenerator, the liquid storage tank, the secondary electronic expansion valve, the outdoor unit, the second heat recovery flow channel of the regenerator, the gas-liquid separator, and then returns to the air intake port of the carbon dioxide compressor through a pipeline to form a heating cycle loop; The exhaust port of the carbon dioxide compressor is connected to the oil separator, the outdoor unit, the primary electronic expansion valve, the first heat recovery flow channel of the regenerator, the liquid storage tank, the secondary electronic expansion valve, the indoor unit, the second heat recovery flow channel of the regenerator, the gas-liquid separator, and then returns to the air intake port of the carbon dioxide compressor through a pipeline to form a refrigeration cycle loop; The subcooling system is connected to the heating cycle and the refrigeration cycle to cool the carbon dioxide refrigerant flowing from the indoor unit and the outdoor unit to the first heat regeneration flow channel of the regenerator; The subcooling system includes a subcooling compressor, a subcooling electronic expansion valve, an intermediate subcooling heat exchanger, a subcooling liquid storage tank, and a subcooling gas-liquid separator. One end of the first heat exchange channel of the intermediate subcooling heat exchanger is connected to the indoor unit and the outdoor unit respectively, and the other end is connected to the first heat regeneration channel of the regenerator. The exhaust port of the subcooling compressor is connected to the indoor unit, the subcooling liquid storage tank, the subcooling electronic expansion valve, the second heat exchange flow channel of the intermediate subcooling heat exchanger, the subcooling gas-liquid separator and then returns to the air intake of the subcooling compressor through a pipeline, forming a heating and subcooling circuit; The exhaust port of the subcooling compressor is connected to the outdoor unit, the subcooling liquid storage tank, the subcooling electronic expansion valve, the second heat exchange flow channel of the intermediate subcooling heat exchanger, the subcooling gas-liquid separator and then returns to the air intake of the subcooling compressor through a pipeline, forming a refrigeration and subcooling circuit; The subcooling compressor is provided with a control device and a frequency converter; the liquid outlet of the subcooling liquid storage tank is provided with a filter; the exhaust port of the subcooling compressor is provided with a high-pressure safety device, and the inlet of the subcooling gas-liquid separator is provided with a low-pressure safety device; the liquid outlet of the subcooling liquid storage tank is provided with a sight glass; The exhaust port of the carbon dioxide compressor is provided with a high-pressure safety device, and the inlet port of the gas-liquid separator is provided with a low-pressure safety device; the outlet port of the gas-liquid separator and the liquid outlet port of the liquid storage tank are both provided with filters.

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