Oil-balancing control of combined air conditioners

Abstract

The invention comprises the following steps: first, connecting in series with an electronic expansion valve on the condenser tubule of each compressor, connecting a low-pressure pressure transducer on the air intake duct and then making the parallel between each electronic expansion valve. When the machine set enters oil-balancing process, the enough differential pressure formed by the pressure between oil cavities of compressors impels the freezing oil to flow directly into the low-pressure compressor to realize the oil balance by regulating the aperture of each electronic expansion valve in the compressor system.

Description

technical field [0001] The invention relates to an air conditioner, in particular to a method for controlling the oil balance of a multi-connected air conditioner capable of adjusting the unbalanced amount of oil between compressors. Background technique [0002] When the multi-line system with parallel compressors is running, due to the difference in the operating status and operating pressure of the compressors, the oil volume between the compressors is often unbalanced. If this unbalanced state is serious, some compressors in the system will be seriously short of oil, which will reduce the service life of the compressor and affect the stability and operating performance of the entire unit. In order to avoid this problem, the multi-line system must adopt an appropriate oil balance method to ensure that the compressors in the unit are always in the best state of oil quantity, to ensure the stability of the unit operation and good use effect. [0003] The basic principle of...

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Problems solved by technology

[0006] 1. When the unit enters oil equalization during normal operation, the sub-unit needs to stop to increase the pressure in its own oil chamber, which will inevitably lead to a significant decline in the capacity of the outdoor unit, thus affecting the user's use effect;

[0007] 2. If the cooling (heating) load of the indoor unit meets the requirements, oil equalization is performed, the main engine needs to increase the operating frequency to reduce the pressure in the oil chamber, and the sub-units that are not running need to be started to reduce the pressure in the oil chamber, which will affect the electric energy. Cause unnecessary waste and increase the user's operating costs;

[0008] 3. When the ambient temperature is very low for heating, it is difficult to achieve the best oil equalization pressure difference by adjusting the operating frequency or capacity of the compressor, which will easily lead to oil equalization failure, which will cause damage to the compressor or reduce the service life

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