Control method and device for multi-connected air conditioning system

Abstract

The invention discloses a control method and device for a multi-connected air-conditioning system, wherein the control method includes: when the current working environment temperature of the multi-connected air-conditioning system is greater than a temperature threshold, detecting whether the working states of N internal units meet the preset state; if so, record the duration of the N indoor units being in the preset state; when the duration is greater than or equal to the first duration threshold, adjust the M indoor units in the heating standby state among the N indoor units to the cooling standby state state, and last for a second duration, M is an integer less than N. According to the control method of the present invention, under some special operating conditions, the refrigerant with a large amount of oil dissolved in the internal unit can be discharged to the gas-liquid separator, thereby effectively avoiding oil shortage in the compressor.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a control method for a multi-connected air-conditioning system and a control device for a multi-connected air-conditioning system. Background technique [0002] The multi-connected air-conditioning system with heat recovery function has different internal units, which can run cooling and heating modes at the same time. For multi-connected air conditioning systems, it has obvious advantages. Among them, the heat recovery multi-connected air-conditioning system mainly includes two-pipe heat recovery multi-connected air-conditioning system and three-pipe heat recovery multi-connected air-conditioning system. cooling mode), pure heating mode (indoor unit only operates in heating mode), main cooling mode (indoor unit operates cooling and heating mode at the same time, at this time, the external unit acts as a condenser) and main heating mode (indoor unit simultaneously Runn...

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Problems solved by technology

[0003] In the related technology, when the heat recovery multi-connected air conditioning system operates under some special operating conditions, for example, when the heating operation is performed in an environment with high indoor and outdoor temperatures, the multi-connected system has the main Due to the characteristics of long pipes, large number of internal unit connections, and large refrigerant injection volume, some internal units in standby will contain a large amount of refrigerant, and oil is dissolved in the refrigerant. Therefore, long-term operation with a large amount of fluid will cause the system to lack oil, thus Lack of oil in the compressor

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