Multi-connected air conditioning outdoor unit, multi-connected air conditioning system and small load operation control method thereof

Abstract

The invention discloses a multi-connected air-conditioning outdoor unit, a multi-connected air-conditioning system and a control method for its small-load operation. The multi-connected air-conditioning outdoor unit includes: a compressor, a first one-way valve, a first four-way valve, The second four-way valve, the first outdoor heat exchanger, the second outdoor heat exchanger, the first electronic throttling component, the second electronic throttling component, the gas side shut-off valve, the liquid side shut-off valve and the second one-way valve. When it is detected that the evaporation temperature of the indoor heat exchanger is low, the system is in low-load cooling operation. By switching part of the outdoor heat exchanger to the evaporator, bypassing part of the refrigerant, unloading part of the capacity output of the compressor, and increasing the low pressure of the system, Increase the evaporation temperature of the indoor heat exchanger, prevent the indoor unit from freezing without stopping the machine, and solve the problem of excessive output of the large-displacement compressor under small load operation, avoid frequent system start-up and stop, and improve user comfort and safety. System operation reliability.

Description

technical field [0001] The invention belongs to the field of electrical appliances, and relates to a multi-connected air conditioner, in particular to a multi-connected air conditioner outdoor unit, a multi-connected air conditioner system and a control method for small-load operation thereof. Background technique [0002] With the development of multi-connection technology, in order to improve the comfort of users, the length of multi-connection piping is getting longer and longer, the number of indoor units is increasing, and the number of outdoor units is required to be larger and larger. The compressor that matches the outdoor unit The displacement is also getting bigger and bigger. For multi-connected systems, variable frequency compressors are generally used, but the variable frequency compressors have a minimum operating frequency. For the volume compressor, the capacity output is still too large, which will cause the low pressure to be low, and the evaporation temper...

AI Technical Summary

Problems solved by technology

However, this practice will cause frequent start and stop of the external unit, which will seriously affect the comfort of users. At the same time, it will increase the oil discharge of the system, make it difficult to return oil, and affect the reliability of the system.

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