Structure for increasing refrigerant circulation volume under low-temperature heating working condition of air conditioner

Abstract

The utility model discloses a structure for increasing the refrigerant circulation volume under the low-temperature heating working condition of an air conditioner, which comprises a compressor, a gas-liquid separator and a hot gas bypass electromagnetic valve, a coil pipe is arranged at the bottom of the gas-liquid separator, and a hot gas inlet of the coil pipe is communicated with an exhaust hole of the compressor. A hot air bypass electromagnetic valve and a throttling device are arranged on a pipeline where a hot air inlet of the coil pipe is communicated with an exhaust hole of the compressor, a hot air outlet of the coil pipe is communicated with an inlet of a gas-liquid separator, and an oil return opening in the bottom of the gas-liquid separator is connected to an air suction opening of the compressor through a pipeline. According to the novel system flow path, during low-temperature heating, liquid refrigerants are prevented from being stored in the gas-liquid separator, the refrigerant circulation amount is increased, the exhaust temperature is reduced, and the rapid heating effect that the system is started for heating for the first time and started for heating after defrosting can be achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of air conditioners, and particularly relates to a structure for improving the refrigerant circulation volume under the low-temperature heating condition of an air conditioner. Background Art

[0002] The refrigerant circulation volume is one of the important factors affecting the low-temperature heating effect of an air conditioner unit. For a multi-connected unit, the low-temperature heating refrigerant control is one of the means to improve the effect. Usually, during low-temperature heating, the exhaust temperature of the compressor is very high, which affects the increase of the compressor frequency, resulting in a low condensation pressure and affecting the effect. An important reason for this phenomenon is that the refrigerant circulation volume is small. When the air-liquid separator is under low-temperature heating, its surface is prone to icing and liquid refrigerant is likely to accumulate, resulting in a small refrigerant circulation volume, a high exhaust temperature, and restricting the increase of the compressor frequency. Moreover, the hot gas bypass circuit returns from the exhaust side to the suction side, only having the function of hot gas bypass and lacking a solution to increase the circulation volume.

[0003] In the existing technical solutions, the air-liquid separator usually adopts the oil return hole oil return and the bottom capillary solenoid valve oil return methods, both of which have their own advantages and disadvantages. From the perspective of the refrigerant circulation volume, the oil return hole has a positive value for increasing the refrigerant circulation volume, but it depends on the pressure difference and can only be continuously conducted; the bottom capillary solenoid valve oil return method can perform stage oil return and refrigerant circulation according to reliability and oil level, with high flexibility. However, compared with the oil return hole, the increase in the refrigerant circulation volume under low-temperature heating is limited and it cannot take both into account at the same time. The current system hot gas bypass design is to bypass from the high-temperature side to the suction side, playing the roles of unloading and hot gas bypass, and cannot realize the reheating of the refrigerant on the low-temperature side, with a relatively single function and unable to increase the refrigerant circulation volume. Summary of the Utility Model

[0004] The utility model provides a structure for improving the refrigerant circulation volume under the low-temperature heating condition of an air conditioner, which solves the problems of high exhaust temperature under low-temperature heating of the air conditioner unit, small refrigerant circulation volume, and poor heating effect caused by the limitation of the compressor frequency.

[0005] To achieve the above object, the utility model provides the following technical solution: A structure for improving the refrigerant circulation volume under the low-temperature heating condition of an air conditioner, including a compressor, an air-liquid separator, and a hot gas bypass solenoid valve. A coil is provided at the bottom of the air-liquid separator. The hot gas inlet of the coil is communicated with the exhaust hole of the compressor. A hot gas bypass solenoid valve and a throttling device are provided on the pipeline where the hot gas inlet of the coil is communicated with the exhaust hole of the compressor. The hot gas outlet of the coil is communicated with the inlet of the air-liquid separator. The oil return port at the bottom of the air-liquid separator is connected to the suction port of the compressor through a pipeline.

[0006] Preferably, the coil adopts a spiral coil.

[0007] Compared with the prior art, the beneficial effects of the utility model are:

[0008] A reheating spiral tube is designed inside the bottom of the gas-liquid separator, which utilizes the system heat to heat the accumulated liquid refrigerant, promotes the gasification cycle of the refrigerant, and at the same time avoids the problem of low-temperature icing and the ice blockage phenomenon of oil return, and is combined with the oil return of the gas-liquid separator to adopt the oil return method of the bottom solenoid valve. With the reheating design at the bottom of the gas-liquid separator, the normally open control of the solenoid valve and the increase of the refrigerant circulation volume can be realized, which has a great positive effect on improving the problem of liquid refrigerant accumulation in the gas-liquid separator.

[0009] Connect the current hot gas bypass and the reheating spiral tube at the bottom of the gas-liquid separator, utilize the refrigerant on the exhaust side for reheating, and return to the suction side after reheating. At the same time, the traditional hot gas bypass function and the reheating function of the gas-liquid separator are realized, which improves the low-temperature heating circulation volume and solves the problems such as high exhaust temperature and poor effect. Description of the Drawings

[0010] Figure 1 It is a structural diagram of the application of the structure of the present invention to an air-conditioning system;

[0011] Figure 2 It is a structural schematic diagram of the coil of the gas-liquid separator of the present invention.

[0012] In the figure: compressor 1, gas-liquid separator 2, hot gas bypass solenoid valve 3, coil 4, hot gas inlet 41, hot gas outlet 42, throttling device 5, oil return assembly 6, oil separator 7, check valve 8, four-way valve 9, outdoor heat exchanger 10, filter 11, electronic expansion valve 12, accumulator 13, subcooling assembly 14, solenoid valve 15, capillary tube 16. Detailed Embodiments

[0013] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0014] Please refer to Figure 1-2 , the present invention provides the following technical solutions: A structure for improving the refrigerant circulation volume in the low-temperature heating condition of an air conditioner, including a compressor 1, a gas-liquid separator 2, and a hot gas bypass solenoid valve 3. A coil 4 is provided at the bottom of the gas-liquid separator 1. The hot gas inlet 41 of the coil 4 is communicated with the exhaust hole of the compressor 1. A hot gas bypass solenoid valve 3 and a throttling device 5 are provided on the pipeline connecting the hot gas inlet 41 of the coil 4 and the exhaust hole of the compressor 1. The hot gas outlet 42 of the coil 4 is communicated with the inlet of the gas-liquid separator 2. The oil return port at the bottom of the gas-liquid separator 2 is connected to the suction port of the compressor 1 through a pipeline. The structure of this embodiment is applied to an air-conditioning system such asFigure 1 As shown, the oil return port of the compressor 1 is connected to the oil return assembly 6, the oil return assembly 6 is connected to the oil separator 7, the oil separator 7 is connected to the check valve 8, the check valve 8 is connected to the four-way valve 9, and the four-way valve 9 is respectively connected to the air pipe, the outdoor heat exchanger 10, and the inlet of the gas-liquid separator 2. One end of the filter 11 is connected to the pipeline between the four-way valve 9 and the check valve 8, and the other end is connected to the hot gas bypass solenoid valve 3 and the throttling device 5. The outdoor heat exchanger 10 is connected to the electronic expansion valve 12, the electronic expansion valve 12 is connected to the liquid receiver 13, the liquid receiver 13 is connected to the subcooling assembly 14, and the liquid receiver 13 is also connected to the inlet of the gas-liquid separator 2 through a pipeline connected with the solenoid valve 15 and the capillary 16. The subcooling assembly 14 is connected to the liquid pipe, and the subcooling assembly 14 is also connected to the inlet of the gas-liquid separator 2 through a pipeline.

[0015] During the heating operation of the air conditioner, the air conditioner unit comprehensively judges through parameters such as the suction and discharge superheat, the discharge temperature, and the operating scenario. When the liquid refrigerant accumulated at the bottom of the gas-liquid separator 2 affects the heating refrigerant circulation volume, by opening the hot gas bypass solenoid valve 3 of the hot gas bypass branch, the high-temperature and high-pressure gaseous refrigerant on the exhaust side of the compressor 1 passes through the filter, passes through the hot gas bypass solenoid valve 3, and flows through the capillary for throttling and pressure reduction. The high-temperature gaseous refrigerant heats the hot refrigerant accumulated at the bottom of the gas-liquid separator 2 through the coil 4, promoting the liquid refrigerant to vaporize into a superheated state and participate in the system cycle, which plays a role in increasing the refrigerant circulation volume and reducing the problem of high discharge temperature caused by the accumulation of refrigerant in the gas-liquid separator 2, and improving the heating performance of the unit. At the same time, this control also retains the hot gas bypass function. When the detected system low pressure is too low, in order to avoid reaching the protection point and ensure the reliability of the compressor, the hot gas bypass solenoid valve 3 is opened for bypass control.

[0016] As a preferred implementation manner of this embodiment, the coil 4 adopts a spiral coil to extend the flow length of the high-temperature gaseous refrigerant and increase the heating area.

[0017] Implementation of control 1: When the open load is greater than 80% in the low-temperature heating scenario, it is judged that the possibility of refrigerant accumulation in the indoor unit is small. In addition, there is refrigerant detection control in the indoor unit, and the indoor EEV (electronic expansion valve) will be slightly opened according to the system superheat and throttle valve opening. The system detects that the suction superheat is lower than 1°C, and the exhaust temperature superheat is greater than 30°C, or the exhaust temperature is greater than 100°C. At this time, in addition to cooling measures, such as opening the jet enthalpy increase circuit to cool down, opening the liquid spray circuit to cool down, etc., the specific volume of the refrigerant is large at low temperatures due to low pressure, resulting in a small actual refrigerant mass flow rate, which is easy to cause problems such as poor exhaust temperature effect when heating at low temperatures. One of the reasons for aggravating the reduction in refrigerant circulation is that when the superheat on the suction side is less than 1°C or 2°C, the suction side of the system is prone to liquid return. The gas-liquid separator is designed with a large volume in most online units, which is easy to accumulate liquid refrigerant. The release through the return oil hole, solenoid valve, etc. is often ineffective. When the system detects that the superheat on the suction side is less than 1°C for 15 minutes, the exhaust temperature superheat is greater than 40°C or the exhaust temperature is greater than 100°C for 15 minutes, and the detection algorithm is added, liquid refrigerant accumulates in the gas-liquid separator. At this time, the system heats the liquid refrigerant by opening the hot gas bypass solenoid valve 3, and exits the control after 5 minutes.

[0018] Implementation of control 2: After heating and defrosting, liquid refrigerant is easy to accumulate in the gas-liquid separator. After defrosting, refrigerant expulsion control is required 30s after the four-way valve is opened. During the refrigerant expulsion control, the compressor frequency is controlled according to the PI calculation. The initial opening of the outdoor unit throttling expansion valve is 40 steps and fixed for 60s, and then switched to superheat control of 10℃. When the exhaust superheat of the detection system is greater than 20℃ or the low pressure is lower than 0.1MPa, the refrigerant expulsion control is exited and switched to normal heating control.

[0019] The gas-liquid separator of this embodiment adopts the bottom solenoid valve oil return method. During low-temperature heating, when the exhaust superheat is greater than 25°C, the bottom solenoid valve should be kept open to achieve oil return and rapid circulation of the refrigerant. When the exhaust superheat is lower than 20°C, it should be closed to avoid liquid return.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A structure for increasing the refrigerant circulation volume of an air conditioner in low-temperature heating conditions, comprising a compressor, a gas-liquid separator, a hot gas bypass solenoid valve, and a throttling device, characterized in that: A coil is provided at the bottom of the gas-liquid separator, and the hot gas inlet of the coil is connected to the exhaust hole of the compressor. A hot gas bypass solenoid valve and a throttling device are provided on the pipeline connecting the hot gas inlet of the coil and the exhaust hole of the compressor. The hot gas outlet of the coil is connected to the inlet of the gas-liquid separator, and the oil return port at the bottom of the gas-liquid separator is connected to the suction port of the compressor through a pipeline.

2. The structure for increasing the refrigerant circulation amount in low-temperature heating conditions of an air conditioner according to claim 1 is characterized in that: The coil is a spiral coil.

Images