Automatic throttling expansion control method

Abstract

The invention relates to the control of refrigeration units, in particular to an automatic throttling expansion control method. It includes the following steps: S1. Obtaining the LTD value of the evaporator; S2. Performing segmental control on the electric regulating valve on the connecting pipeline between the condenser and the evaporator; S3. Stopping the compressor, adjusting the electric regulating valve to the stop opening Vstop%, And make the electric regulating valve keep the shutdown opening, the duration is T 1 , when the time arrives, the electric control valve is closed, and the shutdown opening is the same as the initial opening, T 1 0‑2min. It can be applied to units with large differences in working conditions, especially cooling and heating dual-working condition units, with good stability and adaptability and low control cost.

Description

technical field [0001] The invention relates to the control of refrigeration units, in particular to an automatic throttling expansion control method. Background technique [0002] At present, the existing throttling methods of refrigeration units can be divided into manual and automatic. In the manual throttling expansion device, the unit lacks the ability to adjust working conditions. The automatic adjustment methods are basically controlled according to the liquid level or the superheat of suction and exhaust. These several control methods have certain shortcomings. For example, when liquid level control is used for automatic adjustment, due to the fast discharge speed of the compressor, the liquid level of the refrigerant in the condenser fluctuates greatly, and the control is difficult to stabilize; while the control of suction superheat or exhaust superheat requires additional Increase the suction / discharge temperature sensor to calculate the degree of superheat. At ...

AI Technical Summary

Problems solved by technology

In the manual throttling expansion device, the unit lacks the ability to adjust working conditions

The automatic adjustment method is basically controlled according to the liquid level or the superheat of suction and exhaust. These control methods have certain shortcomings.

For example, when liquid level control is used for automatic adjustment, due to the fast discharge speed of the compressor, the liquid level of the refrigerant in the condenser fluctuates greatly, and the control is difficult to stabilize; while the control of suction superheat or exhaust superheat requires additional Increase the suction / discharge temperature sensor to calculate the degree of superheat. At the same time, there are strict requirements on the installation position of the suction / discharge temperature sensor, and the flow state of the gaseous refrigerant at the suction / discharge port side of the compressor is unstable. There is a large deviation between the temperature and the actual temperature in the unit system, which cannot truly express the operating state of the refrigeration unit system

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