A control method for multi-line low-load refrigeration operation

Abstract

The invention relates to a control method for low load refrigeration operation of a multi-split air conditioner. The multi-split air conditioner comprises a multi-gear outdoor fan, an environment temperature sensor, an exhaust pressure sensor, an air suction pressure sensor, a temperature probe, a supercooling electronic expansion valve and a jet electronic expansion valve. The control method comprises the following steps that the outdoor environment temperature is detected, and opening of the supercooling valve is adjusted along with changes of the outdoor environment temperature; after refrigeration operation is conducted for t minutes, the opening of the supercooling valve and opening of the jet valve are adjusted according to the value of the exhaust superheat degree, and the higher the exhaust superheat degree is, the larger the opening of supercooling valve and the opening of the jet valve are; and an outdoor fan changes according to exhaust pressure of a compressor, and the higher the exhaust pressure is, the higher the rotating speed of the fan is. The control method can prevent the indoor unit freezing phenomenon caused by a too small energy demand or an overlarge energy demand, so that system operation is more reasonable and reliable.

Description

technical field [0001] The invention relates to a control technology of an air-conditioning unit, in particular to a control method suitable for multi-connected refrigeration operation in a low-load state, specifically a control method for multi-connected low-load refrigeration operation. Background technique [0002] With its technical features such as precise control, free use, easy installation, high efficiency and energy saving, the multi-connected air conditioning system is playing an increasingly important role in the field of central air conditioning. Since one outdoor unit in the multi-split system can be connected to multiple indoor units, and the indoor and outdoor temperatures are changing all the time, the load of the multi-split unit changes greatly, especially when the cooling operation is low-load, the indoor unit will The phenomenon of freezing. At present, most of the methods set the minimum load ratio for unit operation, so that the unit will automatically...

AI Technical Summary

Problems solved by technology

However, in this way, the field scope of multi-connected operation is reduced, so many indoor units have to be opened in many operating occasions where only one or two indoor units are used, which wastes a lot of energy and also makes the multi-connected operation status unstable.

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