Heat pump air conditioning unit and control method thereof

Abstract

The application provides a heat pump air conditioning unit and a control method thereof. The heat pump air conditioning unit comprises a main circulation loop, the main circulation loop is provided with a shunt circulation loop, a first throttling device is installed on the shunt circulation loop, a gas-liquid separator is connected to the first throttling device, the gas-liquid separator is communicated with the main circulation loop, the low-temperature heating capacity of the air conditioner in a low-temperature environment is improved, and the daily life needs of people are met. In the heating mode, the two-phase refrigerant after the indoor heat exchanger is partially flowed back to the gas-liquid separator for heat exchange, the suction temperature and the suction pressure in the gas-liquid separator are improved, the refrigerant circulation amount of the unit is improved, and the heating capacity is improved; meanwhile, the oil temperature superheat degree and the suction superheat degree of the unit in the low-temperature environment can be ensured, and the safe and reliable operation of the unit is ensured.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a heat pump air conditioning unit and its control method. Background Technology

[0002] A heat pump air conditioning unit is a circulating system consisting of a compressor, an outdoor unit, and an indoor unit. The refrigerant circulates within the heat pump unit under the action of the compressor, thus enabling cooling in summer or heating in winter. Therefore, heat pump air conditioning units are widely used in residential and commercial buildings to improve the comfort of ambient temperature.

[0003] Because the heating capacity of air conditioning systems decreases in low outdoor temperatures, resulting in insufficient heating capacity of the units, additional electric heating or other heating equipment is needed to supplement it. Therefore, how to improve the heating capacity of heat pump air conditioners in low-temperature environments and ensure the reliable operation of the units in low-temperature environments has been a direction that people have been exploring. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a heat pump air conditioning unit and its control method, which can improve the low-temperature heating capacity of the air conditioner in low-temperature environments and meet people's daily living needs.

[0005] The present invention discloses a heat pump air conditioning unit, including a main circulation loop, wherein the main circulation loop is provided with a branch circulation loop, a first throttling device is installed on the branch circulation loop, a gas-liquid separator is connected to the first throttling device, and the gas-liquid separator is connected to the main circulation loop.

[0006] As a further optimization of the present invention, a compressor is installed on the main circulation loop, a four-way valve is connected to the compressor, one end of the four-way valve is connected to an indoor heat exchanger, and the indoor heat exchanger is connected to the heat exchange tube inlet of the gas-liquid separator.

[0007] As a further optimization of the present invention, an outdoor heat exchanger is connected to the outlet of the heat exchange tube of the gas-liquid separator, and the outlet of the outdoor heat exchanger is connected to the inlet of the heat exchange tube of the gas-liquid separator.

[0008] As a further optimization of the present invention, a second throttling device is provided between the indoor heat exchanger and the gas-liquid separator.

[0009] As a further optimization of the present invention, a third throttling device is provided between the heat exchange tube outlet of the gas-liquid separator and the outdoor heat exchanger.

[0010] As a further optimization of the present invention, the first throttling device, the second throttling device, or the third throttling device includes one or more of an electronic expansion valve and a capillary tube.

[0011] As a further optimization of the invention, a controller is also included, which is electrically connected to the electronic expansion valve.

[0012] As a further optimization of the present invention, it also includes an ambient temperature sensor for detecting ambient temperature, the ambient temperature sensor being electrically connected to the controller.

[0013] A control method for a heat pump air conditioning unit includes the following steps:

[0014] Obtain ambient temperature information;

[0015] When the ambient temperature is lower than the preset value, the compressor is controlled to process the refrigerant under high temperature and high pressure.

[0016] After processing is completed, the four-way valve is opened to allow the high-temperature and high-pressure refrigerant to flow into the main circulation loop and the branch circulation loop for cooling and / or depressurization.

[0017] As a further optimization of the present invention, the cooling and / or depressurization treatment of the refrigerant includes controlling the refrigerant in the main circulation loop to enter the indoor heat exchanger for condensation and heat release.

[0018] As a further optimization of the present invention, the refrigerant cooling and / or depressurization treatment includes controlling the refrigerant in the main circulation loop to undergo subcooling treatment in a gas-liquid separator.

[0019] As a further optimization of the present invention, the refrigerant cooling and / or depressurization treatment includes controlling the refrigerant in the diversion circulation loop to perform throttling treatment.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention discloses a heat pump air conditioning unit, including a main circulation loop, wherein the main circulation loop is provided with a branch circulation loop, a first throttling device is installed on the branch circulation loop, and a gas-liquid separator is connected to the first throttling device. The gas-liquid separator is connected to the main circulation loop, thereby improving the low-temperature heating capacity of the air conditioner in low-temperature environments and meeting people's daily needs.

[0022] In the heating mode, the heat pump air conditioning unit of the present invention allows the gas-liquid two-phase refrigerant portion after exiting the indoor heat exchanger to flow back to the gas-liquid separator for heat exchange, thereby increasing the suction temperature and suction pressure in the gas-liquid separator, as well as increasing the refrigerant circulation volume of the unit and increasing the heating capacity; at the same time, it can ensure the oil temperature superheat and suction superheat of the unit in low-temperature environments, ensuring the safe and reliable operation of the unit. Attached Figure Description

[0023] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the structure of the heat pump air conditioning unit described in this invention.

[0025] In the above diagrams, 1. Main circulation loop; 2. Diversion circulation loop; 3. First throttling device; 4. Gas-liquid separator; 5. Compressor; 6. Four-way valve; 7. Indoor heat exchanger; 8. Outdoor heat exchanger; 9. Second throttling device; 10. Third throttling device; 11. Controller; 12. Ambient temperature sensor.

[0026] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale. Detailed Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the present invention provides a heat pump air conditioning unit, including a main circulation loop 1, wherein the main circulation loop 1 is provided with a branch circulation loop 2, a first throttling device 3 is installed on the branch circulation loop 2, and a gas-liquid separator 4 is connected to the first throttling device 3. The gas-liquid separator 4 is connected to the main circulation loop 1 to improve the low-temperature heating capacity of the air conditioner in low-temperature environments and meet people's daily needs.

[0029] In the heating mode, the heat pump air conditioning unit of the present invention allows the gas-liquid two-phase refrigerant portion after exiting the indoor heat exchanger to flow back to the gas-liquid separator for heat exchange, thereby increasing the suction temperature and suction pressure in the gas-liquid separator, as well as increasing the refrigerant circulation volume of the unit and increasing the heating capacity; at the same time, it can ensure the oil temperature superheat and suction superheat of the unit in low-temperature environments, ensuring the safe and reliable operation of the unit.

[0030] In this embodiment, a compressor 5 is installed on the main circulation loop 1, and a four-way valve 6 is connected to the compressor 5. One end of the four-way valve 6 is connected to an indoor heat exchanger 7, which is connected to the inlet of the heat exchange tube of the gas-liquid separator 4. Thus, the refrigerant leaving the indoor heat exchanger in the main circulation loop exchanges heat with the refrigerant in the gas-liquid separator. This allows the refrigerant in the main circulation loop to be subcooled in the gas-liquid separator when the unit is operating at low temperatures, thereby improving the heat absorption capacity of the refrigerant in the outdoor heat exchanger. Simultaneously, the liquid refrigerant in the gas-liquid separator absorbs heat and vaporizes, preventing the compressor from drawing in refrigerant containing liquid.

[0031] In another embodiment of the present invention, unlike the above embodiments, an outdoor heat exchanger 8 is connected to the heat exchange tube outlet of the gas-liquid separator 4 in this embodiment. The outlet of the outdoor heat exchanger 8 is connected to the heat exchange tube inlet of the gas-liquid separator 4, so that the heat of the indoor heat exchanger and the outdoor heat exchanger are balanced, ensuring that the system has sufficient refrigerant circulation under low temperature conditions.

[0032] In another embodiment of the present invention, unlike the above embodiments, a second throttling device 9 is provided between the indoor heat exchanger 7 and the gas-liquid separator 4. This increases the unit's evaporation pressure, reduces unit frosting, and improves product performance.

[0033] In another embodiment of the present invention, unlike the above embodiments, a third throttling device 10 is provided between the heat exchange tube outlet of the gas-liquid separator 4 and the outdoor heat exchanger 8. This increases the unit's evaporation pressure, reduces unit frosting, and improves product performance.

[0034] In another embodiment of the present invention, unlike the embodiments described above, the first throttling device 3, the second throttling device 9, or the third throttling device 10 in this embodiment includes one or more of an electronic expansion valve and a capillary tube. Therefore, the bypass flow can be adjusted at different ambient temperatures to increase the unit's evaporation pressure, reduce unit frosting, and improve product performance.

[0035] In another embodiment of the present invention, unlike the above embodiments, the heat pump air conditioning unit in this embodiment further includes a controller 11, which is electrically connected to the electronic expansion valve. This enables intelligent control of the heat pump air conditioning unit.

[0036] As another embodiment of the present invention, unlike the above embodiments, the heat pump air conditioning unit in this embodiment also includes an ambient temperature sensor 12 for detecting ambient temperature. The ambient temperature sensor 12 is electrically connected to the controller 11, so that the heat pump air conditioning unit can perform low-temperature heating according to the ambient temperature.

[0037] A control method for a heat pump air conditioning unit includes the following steps:

[0038] S1. Obtain ambient temperature information;

[0039] S2. When the ambient temperature is lower than the preset value, control the compressor to process the refrigerant at high temperature and high pressure.

[0040] S3. After processing, control the four-way valve to open so that the high-temperature and high-pressure refrigerant flows into the main circulation loop and the branch circulation loop respectively for cooling and / or pressure reduction.

[0041] As another embodiment of the present invention, unlike the above embodiments, the refrigerant cooling and / or depressurization treatment in this embodiment includes controlling the refrigerant in the main circulation loop to enter the indoor heat exchanger for condensation and heat release, thereby realizing the heating function of the unit.

[0042] In another embodiment of the present invention, unlike the above embodiments, the refrigerant cooling and / or depressurization process in this embodiment includes controlling the refrigerant in the main circulation loop to undergo subcooling in the gas-liquid separator. Thus, the refrigerant leaving the indoor heat exchanger in the main circulation loop exchanges heat with the refrigerant in the gas-liquid separator, causing the main circuit refrigerant to be subcooled in the gas-liquid separator during low-temperature operation of the unit. This improves the heat absorption capacity of the refrigerant in the outdoor heat exchanger, while the refrigerant liquid in the gas-liquid separator absorbs heat and vaporizes, preventing the compressor from drawing in refrigerant containing liquid.

[0043] As another embodiment of the present invention, unlike the above embodiments, the refrigerant cooling and / or pressure reduction treatment in this embodiment includes controlling the refrigerant in the split circulation loop to throttle. This allows the high-pressure gas discharged from the compressor to be throttled to a low pressure, mixed and exchanged with the refrigerant in the main circuit, and then enters the gas-liquid separator, balancing the heat between the indoor and outdoor heat exchangers and ensuring sufficient refrigerant circulation for the system under low-temperature operating conditions.

[0044] When the heat pump air conditioning unit of the present invention is running in low-temperature heating mode, the high-temperature and high-pressure refrigerant gas after being switched by the four-way valve is divided into a main circulation loop and a branch circulation loop. The main circulation loop enters the indoor heat exchanger for condensation and heat release, while the branch circulation loop is connected to the inlet of the gas-liquid separator and merges with the main circulation loop. In the branch circulation loop, the refrigerant is directly throttled from the high-pressure exhaust to the low-pressure, mixes and exchanges heat with the refrigerant in the main circuit, and enters the gas-liquid separator, so as to balance the heat between the indoor heat exchanger and the outdoor heat exchanger and ensure that the system has a sufficient amount of refrigerant circulation when operating in low-temperature conditions.

[0045] The addition of subcooling in this invention lowers the inlet temperature of the electronic expansion valve, increasing the heat absorption capacity of the refrigerant evaporator. Because the refrigerant absorbs heat and evaporates into gas as it flows along the evaporator pipes, the liquid refrigerant content in the downstream pipe section decreases, or even disappears entirely. In this case, if the specific volume of the refrigerant in the pipes increases, it will significantly reduce the heat absorption capacity of the evaporator and lower the unit's energy efficiency ratio. Therefore, to improve the liquid content and heating efficiency in the evaporator pipes, a subcooling must be added to the unit.

[0046] In the gas-liquid separator of the present invention, the evaporator return steam and the refrigerant liquid contained therein exchange heat with the refrigerant under the condensing pressure in the subcooling section and absorb heat from it, causing the refrigerant liquid contained in the return steam to evaporate, thereby increasing the suction pressure of the compressor, reducing the suction specific volume, and increasing the refrigerant circulation volume of the system.

[0047] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A heat pump air conditioning unit, characterized in that: The system includes a main circulation loop, which is equipped with a branch circulation loop. A first throttling device is installed on the branch circulation loop, and a gas-liquid separator is connected to the first throttling device. The gas-liquid separator is connected to the main circulation loop. A compressor is installed on the main circulation loop, and a four-way valve is connected to the compressor. One end of the four-way valve is connected to an indoor heat exchanger. The inlet of the branch circulation loop is located between the indoor heat exchanger and the four-way valve. The indoor heat exchanger is connected to the inlet of the heat exchange tube of the gas-liquid separator. An outdoor heat exchanger is connected to the outlet of the heat exchange tube of the gas-liquid separator, and the outlet of the outdoor heat exchanger is connected to the inlet of the heat exchange tube of the gas-liquid separator. In the branch circulation loop, the refrigerant is directly throttled from high-pressure exhaust to low-pressure, mixes and exchanges heat with the refrigerant in the main circuit, and enters the gas-liquid separator. A second throttling device is installed between the indoor heat exchanger and the gas-liquid separator.

2. The heat pump air conditioning unit according to claim 1, characterized in that: A third throttling device is provided between the heat exchange tube outlet of the gas-liquid separator and the outdoor heat exchanger.

3. The heat pump air conditioning unit according to claim 2, characterized in that: The first, second, or third throttling device includes one or more of an electronic expansion valve and a capillary tube.

4. The heat pump air conditioning unit according to claim 3, characterized in that: It also includes a controller, which is electrically connected to the electronic expansion valve.

5. The heat pump air conditioning unit according to claim 4, characterized in that: It also includes an ambient temperature sensor for detecting ambient temperature, which is electrically connected to the controller.

6. A control method for a heat pump air conditioning unit according to any one of claims 1-5, characterized in that, Includes the following steps: Obtain ambient temperature information; When the ambient temperature is lower than the preset value, the compressor is controlled to process the refrigerant under high temperature and high pressure. After processing is completed, the four-way valve is opened to allow the high-temperature and high-pressure refrigerant to flow into the main circulation loop and the branch circulation loop for cooling and / or depressurization.

7. The control method for a heat pump air conditioning unit according to claim 6, characterized in that: The cooling and / or depressurization of the refrigerant includes controlling the refrigerant in the main circulation loop to enter the indoor heat exchanger for condensation and heat release.

8. The control method for a heat pump air conditioning unit according to claim 7, characterized in that: The refrigerant cooling and / or depressurization process includes controlling the refrigerant in the main circulation loop to undergo subcooling in the gas-liquid separator.

9. The control method for a heat pump air conditioning unit according to claim 8, characterized in that: The cooling and / or depressurization of the refrigerant includes throttling the refrigerant in the diversion circulation loop.

Images