Variable refrigerant flow air conditioning system and control method thereof

Abstract

Disclosed is a variable refrigerant flow air conditioning system. The variable refrigerant flow air conditioning system is mainly composed of an outdoor unit, an indoor unit and a controller. The outdoor unit is formed by parallel connection of a first outdoor unit and a second outdoor unit. When one of the outdoor units needs defrosting operation, refrigerating fluid of a heating operating loop and refrigerating fluid of a defrosting operating loop are separated through opening and closing of an electromagnetic valve and an electronic expansion valve, and therefore heating and defrosting can not affect each other. Meanwhile, the refrigerating fluid circulation amounts in the heating loop and the defrosting loop are adjusted through control of the electromagnetic valve and the electronic expansion valve, the heating amount of the indoor unit is guaranteed through improvement of the frequency of a compressor corresponding to a heating operating system, and therefore the heat comfort degree of the indoor unit can be guaranteed. According to the variable refrigerant flow air conditioning system, normal heating of the indoor unit in the process of the defrosting operation can be guaranteed; and besides, in the process of entering and exiting from the defrosting process, the compressor does not need to be shut down, a four-way valve does not need to be reversed, and therefore defrosting operation time is greatly shortened, and comfortableness of an indoor environment is effectively improved.

Description

technical field [0001] The invention relates to a multi-connected air-conditioning system and a control method thereof, belonging to the field of indoor air conditioning. Background technique [0002] When the air conditioner is running in heating mode, frost will form on the outdoor heat exchanger. If the frost on the outdoor heat exchanger cannot be removed in time, the heat exchange capacity of the outdoor heat exchanger will be reduced or even lost, resulting in a reduction in the heating capacity of the air conditioner or no heating, and the thermal comfort of the user cannot be guaranteed. [0003] For this reason, present air-conditioning has been provided with automatic defrosting function. During automatic defrosting, the air conditioner operates in cooling mode, and the outdoor heat exchanger dissipates heat to the outside to melt the frost layer on it; while the indoor heat exchanger absorbs heat, causing the ambient temperature to drop. Therefore, when the curr...

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Problems solved by technology

[0006] The present invention aims to solve the problems that the compressor starts and stops, the direction of the four-way valve changes, and the indoor thermal comfort cannot be guaranteed due to automatic defrosting when the above-mentioned air conditioner is running in the heating mode.

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