Control method of minimum opening of air conditioning expansion valves and air conditioning expansion valves

Abstract

The invention provides a control method of minimum opening of air conditioning expansion valves and air conditioning expansion valves, and the method comprises following steps: collecting the inlet temperature of an evaporator; determining a target temperature; calculating a difference value between the collected inlet temperature of the evaporator and the target temperature; obtaining a deviation value of the inlet temperature of the evaporator; determining the minimum opening of the expansion valves according to the deviation value of the inlet temperature of the evaporator; and ensuring the opening of the expansion valves by combining the minimum opening of the expansion valves with the opening of the expansion valves obtained by other control methods, thereby overcoming the limitations and problems of the minimum opening of the expansion valves set by the existing control method.

Description

technical field [0001] The invention relates to an air conditioner control method, in particular to a small opening degree of an air conditioner expansion valve and a control method for the air conditioner expansion valve. Background technique [0002] With the maturity of electronic expansion valve technology, more and more air-conditioning manufacturers use expansion valves to precisely control the flow of refrigerant. Since the expansion valve is one of the key components of the air-conditioning and refrigeration system, the quality of the control of the opening of the expansion valve is the key to determining the performance of the air-conditioning system, and has a great impact on the stability, safety and economy of the entire air-conditioning system. At present, the control of the opening degree of the expansion valve is mostly used to control the superheat of the evaporator, such as image 3 Shown, the temperature difference t across the inlet and outlet of the evapo...

AI Technical Summary

Problems solved by technology

[0006] (1) g min The value limit of : Generally speaking, the actual determined g min must be greater than g c , while at design time, g c It is difficult to determine, there are two reasons: one is the mass-produced expansion valve opening position g 0 inconsistent, causing g c There is a certain deviation; the second is g c It is closely related to the evaporator, the same expansion valve used in different evaporators will get different g c

So determine g min Sometimes the subjectivity and experience are relatively large, and it may be more suitable under certain working conditions and models, but it is difficult to adapt to the change of working conditions or models.

[0007] (2) g min The scope of application is limited: due to (1) reasons, the fixed value of g min The scope of application is very limited, and it is difficult to use a wide range of fluctuations in working conditions

In actual operation, there is often a problem of taking care of one thing and losing another, and finally have to set an intermediate value. However, under severe extreme working conditions, there will be poor control quality and unstable system operation, such as abnormal compressor frequency and air conditioning effect. Poor, expansion valve opening fluctuates, etc.

[0008] (3) Affecting the economy of system operation: unreasonably fixed g min The value of , while causing system fluctuations, increases energy consumption. When the system is unstable, the effect is often poor, and it takes longer time and power to achieve good results.

For example, when the heating internal unit is shut down now, the opening of the expansion valve is often limited by g min , resulting in a waste of capacity and a decrease in system ERR

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