Refrigerant flow control method for multi-connected air-conditioning system during heating

Abstract

The invention discloses a refrigerant flow control method for a multi-connected air-conditioning system during heating. The refrigerant flow control method controls the refrigerant flow in the system by adjusting the opening of an electronic expansion valve in a switched-off indoor unit, and comprises the following steps: a. enabling the air-conditioning system to enter a heating operational mode; b. switching off or switching on the valve according to the condensing pressure and evaporating pressure of the system; c. switching on the valve according to the exhaust temperature of a compressor; and d. switching off or switching on the valve according to the condensing saturation temperature converted from the condensing pressure or according to the coil temperature of the switched-on indoor unit, the coil temperature of the switched-off indoor unit, the outlet temperature of a heat exchanger in the switched-off indoor unit and the inlet temperature of the heat exchanger in the switched-off indoor unit. The dynamic equilibrium control strategy for a refrigerant provided by the invention can automatically adjust the opening of the electronic expansion valve in the switched-off indoorunit according to the system operation conditions, thereby avoiding energy waste and reduced heating effect caused by overlarge deviation of the opening of the expansion valve, and improving the heating performance of the air-conditioning system.

Description

technical field [0001] The invention belongs to the technical field of air-conditioning systems, and in particular relates to a method for controlling the flow of refrigerant in the multi-connected air-conditioning system when it operates in a heating mode. Background technique [0002] When heating, the multi-connected air conditioner requires the shut-off indoor unit to maintain a certain amount of refrigerant flow, so as to avoid excessive accumulation of refrigerant in the shut-down indoor unit, causing insufficient circulation of refrigerant in the system. When the existing multi-connected air-conditioning system is heating, the closed indoor unit generally adopts the method of opening its internal electronic expansion valve to a fixed opening to ensure that the refrigerant circulates in the system. However, for the existing electronic expansion valve production technology, it is impossible to ensure that the electronic expansion valve is opened accurately at a certain ...

AI Technical Summary

Problems solved by technology

In this way, the actual opening of the expansion valve of the indoor unit (that is, the electronic expansion valve that can be opened in 20 steps) will be too large, and the shut-down indoor unit will bypass a large amount of refrigerant, resulting in energy waste and reducing the start-up. Heating effect of indoor unit

Similarly, for the expansion valve of the indoor unit that is shut down on the upper side (that is, the electronic expansion valve that can only be opened after 60 steps), the actual opening will be too small, so that a large amount of refrigerant will accumulate in the indoor unit, causing the system to cycle. Insufficient amount of refrigerant leads to poor heating effect of the indoor mechanism and lower energy efficiency

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