Multi-connected system and its mode switching control method

Abstract

The invention discloses a multiple-on-line system and a mode switching control method thereof. The method includes the steps that running parameters of all indoor units are obtained, and saturation temperatures Tc and Te corresponding to the exhaust pressure and the gas return pressure of a compressor are obtained; when the starting volumes of the indoor units change, if the an outdoor unit is in a PI control state before a first preset time, change values of Tc and Te within a preset time interval are smaller than a first threshold value and a second threshold value, and a first temperature value T1 and a second temperature value T2 corresponding to the heating indoor unit and the refrigeration indoor unit are calculated according to Tc and Te; total heat exchange amounts Qh and Qc of the heating indoor unit and the refrigeration indoor unit are calculated according to T1, T2 and the running parameters of all indoor units; and the multiple-on-line system is controlled to conduct mode switching according to the relation between Qh and Qc. According to the method, when the starting volumes of the indoor units change, a running mode actually needed by the multiple-on-line system can be accurately and rapidly judged, and the problem of insufficient indoor unit capacity caused by mode switching lag is avoided.

Description

technical field [0001] The present invention relates to the technical field of air conditioners, in particular to a mode switching control method of a multi-connection system and a multi-connection system. Background technique [0002] For the air-conditioning system that uses a multi-connected air-conditioning system, there are often both cooling loads and heating loads. Even in the environmental conditions of winter, there will be cooling requirements. For example, the meeting room in the center of the building is surrounded by heated rooms and the room temperature is high. When the number of people in the meeting room suddenly increases, the temperature will easily rise and cause cooling load. [0003] When the cooling load required for a short time is greater than the heating load, and the cooling load decreases, causing the cooling load to be less than the heating load again, the operation mode of the outdoor unit must remain in the original mode for a period of time, w...

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Problems solved by technology

[0003] When the cooling load required for a short time is greater than the heating load, and the cooling load decreases, causing the cooling load to be less than the heating load again, the operation mode of the outdoor unit must remain in the original mode for a period of time, which will cause some indoor The machine's ability to deteriorate, in some operating conditions, this situation can last for a considerable period of time, thereby affecting the user's comfort

[0004] In related technologies, the operating mode of the outdoor unit is judged by the ratio of the operating capacity of the indoor unit. However, due to the wide range of indoor temperatures, the operating capacity of the indoor unit cannot reflect the actual capacity demand, so it is difficult to make an accurate judgment on the operating mode of the outdoor unit.

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