Control method for auxiliary oil return of multi-split air conditioning system

Abstract

The invention provides a control method for auxiliary oil return of a multi-split air conditioning system, which comprises the following steps: when an outdoor unit is not started, a first bidirectional electromagnetic valve and a second bidirectional electromagnetic valve are both in a closed state, and when the starting capacity of an indoor unit is greater than 0% and less than or equal to 35% of the capacity of the outdoor unit, the first bidirectional electromagnetic valve is opened, and the second bidirectional electromagnetic valve is closed; when the outdoor unit capacity is larger than 35% and the indoor unit starting capacity is smaller than or equal to 70%, the first two-way electromagnetic valve is opened, and the second two-way electromagnetic valve is opened; when the starting capacity of the indoor unit is larger than 70% of the capacity of the outdoor unit, the first two-way electromagnetic valve and the second two-way electromagnetic valve are opened. And oil return of the compressor is reliable, frequent oil return control is avoided, and therefore refrigerant flowing sound is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-connected air conditioning, in particular to a control method for auxiliary oil return of a multi-connected air conditioning system. BACKGROUND

[0002] The multi-connected air conditioning is connected with multiple indoor units by one outdoor unit, and the pipeline specification of the connected pipeline is designed according to 100% capacity. When the operating capacity is 100%, the flow rate of the air pipe can meet the demand for oil return. When the operating load is small, under the condition of the same pipe diameter, the flow rate is reduced, and the compressor oil in the connected pipeline cannot be brought back to the compressor, which can cause the compressor to run out of oil and break down. In view of the above situation, each manufacturer can compile an oil return control program according to the oil throwing amount and operating time of the compressor under different operating frequencies. Generally, the compressor frequency is increased, the temperature sensor is closed, the indoor EEV valve is opened, the temperature sensor is opened, and the indoor EEV valve is increased to complete the oil return. However, the above situation can cause two problems. The first problem is that the forced frequency increase can break the original system balance and then restore to the original balance state, and the power consumption of the compressor is increased. The second problem is that the temperature sensor is closed, the indoor EEV valve is opened, the temperature sensor is opened, and the indoor EEV valve is increased, and a large amount of refrigerant flows, which can produce a refrigerant flow sound and affect the user experience. SUMMARY

[0003] The present application provides a control method for auxiliary oil return of a multi-connected air conditioning system, which can solve the problems of large power consumption and refrigerant flow sound caused by the oil return control of the existing multi-connected air conditioning.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme: a control method for auxiliary oil return of a multi-connected air conditioning system, the multi-connected air conditioning system comprising an outdoor unit and at least one indoor unit, further comprising an auxiliary oil return device, the auxiliary oil return device being arranged between the air pipe of the indoor unit and the four-way valve of the outdoor unit, the auxiliary oil return device comprising a first oil return pipeline and a second oil return pipeline connecting the four-way valve and the air pipe, a first bidirectional electromagnetic valve and a first air pipe operation valve being arranged on the first oil return pipeline, and a second bidirectional electromagnetic valve and a second air pipe operation valve being arranged on the second oil return pipeline; The control method comprises: when the outdoor unit is not started, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve are in a closed state, when 0% < the operating capacity of the indoor unit ≤ 35% of the operating capacity of the outdoor unit, the first bidirectional electromagnetic valve is opened, and the second bidirectional electromagnetic valve is closed; when 35% of the operating capacity of the outdoor unit < the operating capacity of the indoor unit ≤ 70% of the operating capacity of the outdoor unit, the first bidirectional electromagnetic valve is opened, and the second bidirectional electromagnetic valve is opened; when the operating capacity of the indoor unit > 70% of the operating capacity of the outdoor unit, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve are both opened.

[0005] Preferably, the diameter of the first and second bidirectional electromagnetic valves is 10-15mm.

[0006] Preferably, the first and second gas pipe operating valves are selected to satisfy that the difference between the sum of the flow cross-sectional areas of the first and second oil return pipes and the flow cross-sectional area of the original connection pipe is within ±0.5mm. 2

[0007] Preferably, the entering condition of the control method is that the indoor unit opening capacity is greater than 0KW, the compressor is opened, and the compressor opening protection condition is satisfied, wherein the compressor opening protection condition is that the compressor is opened after the shutdown time is greater than 3min.

[0008] Compared with the prior art, the advantages and positive effects of the present application are that the combined opening type of the first and second bidirectional electromagnetic valves can ensure that the refrigerant has a high flow rate in the gas pipe under different opening capacities, so that the compressor oil does not exist in large quantities in the gas pipe, especially when the long pipe is arranged, thereby ensuring the reliability of the compressor; at the same time, frequent entering of the oil return control can be avoided, thereby reducing the refrigerant flow sound. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 It is the schematic diagram of the multi-connected air conditioning system of the present application.

[0010] Annotations in the figure are as follows: First oil return pipe 1, second oil return pipe 2, first bidirectional electromagnetic valve 3, first gas pipe operating valve 4, second bidirectional electromagnetic valve 5, and second gas pipe operating valve 6. DETAILED DESCRIPTION

[0011] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described below through examples. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0012] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the present application is not limited to the specific embodiments disclosed in the following description.

[0013] As Figure 1 ​As shown, the embodiment provides a control method for auxiliary oil return of a multi-split air conditioning system. The multi-split air conditioning system includes an outdoor unit and at least one indoor unit. The indoor unit includes an indoor heat exchanger, an electronic expansion valve EEV, an ambient temperature sensor Thi-A, and the like. The outdoor unit includes a compressor, a gas-liquid separator, an oil return solenoid valve, an oil return capillary, an oil separator, a one-way valve, a four-way valve, an outdoor heat exchanger, an electronic expansion valve EEVH, a reservoir, and the like. The connection relationship between the components of the indoor unit and the outdoor unit, and the connection relationship between the indoor unit and the outdoor unit belong to the prior art and will not be described in detail. On the basis of the prior art, the multi-split air conditioning system of the embodiment further includes an auxiliary oil return device. The auxiliary oil return device is arranged between a gas pipe of the indoor unit and a four-way valve of the outdoor unit. The auxiliary oil return device includes a first oil return pipeline 1 and a second oil return pipeline 2 connecting the four-way valve and the gas pipe. A first bidirectional solenoid valve 3 and a first gas pipe operation valve 4 are arranged on the first oil return pipeline 1. A second bidirectional solenoid valve 5 and a second gas pipe operation valve 6 are arranged on the second oil return pipeline 2.

[0014] The control method includes: when the outdoor unit is not started, the first bidirectional solenoid valve 3 and the second bidirectional solenoid valve 4 are in a closed state, when 0% < the starting capacity of the indoor unit ≤ 35% of the capacity of the outdoor unit, the first bidirectional solenoid valve 3 is opened, and the second bidirectional solenoid valve 4 is closed; when 35% of the capacity of the outdoor unit < the starting capacity of the indoor unit ≤ 70% of the capacity of the outdoor unit, the first bidirectional solenoid valve 3 is opened, and the second bidirectional solenoid valve 4 is opened; when the starting capacity of the indoor unit > 70% of the capacity of the outdoor unit, the first bidirectional solenoid valve 3 and the second bidirectional solenoid valve 4 are both opened.

[0015] As a preferred embodiment of the embodiment, the diameters of the first bidirectional solenoid valve 3 and the second bidirectional solenoid valve 4 are both 10-15 mm, and both are normally closed solenoid valves.

[0016] As a preferred embodiment of the embodiment, the selection of the first gas pipe operation valve 5 and the second gas pipe operation valve 6 should satisfy that the difference between the sum of the flow cross-sectional areas of the first oil return pipeline 1 and the second oil return pipeline 2 and the flow cross-sectional area of the original split pipe is within ±0.5 mm 2 . Specifically, the diameter of the first gas pipe operation valve 5 is 9.52 mm, the diameter of the second gas pipe operation valve 6 is 12.7 mm, the diameter of the first oil return pipeline 1 connected to the first gas pipe operation valve 5 is 9.52 mm, and the wall thickness is 0.6 mm. The cross-sectional area of the first oil return pipeline 1 is 54.3 mm 2 . The diameter of the second oil return pipeline 2 connected to the second gas pipe operation valve 6 is 12.7 mm, and the wall thickness is 0.8 mm. The cross-sectional area of the second oil return pipeline 2 is 96.7 mm 2The cross-sectional area of the online pipe used in the prior art is 151.2mm 2 It can be seen from the calculation that the flow area of the 15.88mm online pipe is equivalent to the flow areas of the first and second oil return pipelines.

[0017] As a preferred embodiment of the present embodiment, the entering condition of the control method is that the indoor unit capacity is greater than 0KW, the compressor is started, and the compressor starting protection condition is met, and the compressor starting protection condition is that the compressor is started after the shutdown time is greater than 3 minutes.

[0018] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments without departing from the technical solution content of the present application still belongs to the protection scope of the present application technical solution.

Claims

1. A control method for auxiliary oil return in a multi-split air conditioning system, the multi-split air conditioning system comprising an outdoor unit and at least one indoor unit, characterized in that: It also includes an auxiliary oil return device, which is installed between the gas pipe of the indoor unit and the four-way valve of the outdoor unit. The auxiliary oil return device includes a first oil return pipeline and a second oil return pipeline connecting the four-way valve and the gas pipe. A first bidirectional solenoid valve and a first gas pipe operating valve are provided on the first oil return pipeline, and a second bidirectional solenoid valve and a second gas pipe operating valve are provided on the second oil return pipeline. The control method includes: when the outdoor unit is not turned on, both the first bidirectional solenoid valve and the second bidirectional solenoid valve are in the closed state. When 0% < indoor unit operating capacity ≤ 35% outdoor unit capacity, the first two-way solenoid valve opens and the second two-way solenoid valve closes. When 35% of the outdoor unit capacity < indoor unit operating capacity ≤ 70% of the outdoor unit capacity, the first two-way solenoid valve opens and the second two-way solenoid valve opens. When the indoor unit's operating capacity is greater than 70% of the outdoor unit's capacity, both the first and second bidirectional solenoid valves will open.

2. The control method for auxiliary oil return in a multi-split air conditioning system according to claim 1, characterized in that: The diameters of both the first and second bidirectional solenoid valves are 10-15 mm.

3. The control method for auxiliary oil return in a multi-split air conditioning system according to claim 1, characterized in that: The selection of the first and second air pipe operating valves must ensure that the difference between the sum of the flow cross-sectional areas of the first and second return oil lines and the flow cross-sectional area of ​​the original connecting pipe is within ±0.5 mm. 2 Within.

4. The control method for auxiliary oil return in a multi-split air conditioning system according to claim 1, characterized in that: The entry conditions for the control method are that the indoor unit's operating capacity is greater than 0KW, the compressor is turned on, and the compressor's start-up protection conditions are met. The compressor's start-up protection conditions are that the compressor must be turned off for more than 3 minutes before it can be turned on again.

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