Multistage compressor, air conditioning system and controlling method of multistage compressor

Abstract

The invention discloses a multistage compressor, an air conditioning system and a controlling method of the multistage compressor. The multistage compressor comprises at least one high-pressure stage cylinder and at least one low-pressure stage cylinder, wherein a bypass hole is formed in the side wall, corresponding to the suction side of the high-pressure stage cylinder and is communicated with the suction hole of the high-pressure stage cylinder through a bypass backflow passage; and in addition, the bypass backflow passage is provided with a control mechanism for controlling on-off of an airflow. According to the multistage compressor, with the arrangement, adjustable volume ratio of the compressor can be realized, the compressor does not have fixed volume ratio any longer, and therefore, the volume ratio can be adjusted to the optimal volume ratio corresponding to the working condition when the compressor runs under different working condition loads, the working condition adaptation of the compressor is better, and the comprehensive energy efficiency of the compressor is better compared with that of the whole multistage compressor with fixed volume ratio.

Description

technical field [0001] The invention relates to the technical field of air conditioning, and more specifically, relates to a multistage compressor, an air conditioning system and a control method for the multistage compressor. Background technique [0002] With the increasing requirements on the energy efficiency of air conditioners worldwide, how to improve the overall energy efficiency of compressors is a technical problem to be solved urgently by those skilled in the art. The existing technology mainly improves the environmental adaptability of the compressor by changing the displacement of the compressor, or adopts a two-stage enthalpy increase technology to improve the capacity and energy efficiency ratio of the compressor under high temperature / low temperature conditions. [0003] The patent documents with application number CN200910178425.0 and application number CN201120255956.8 respectively disclose a compressor with variable capacity. By setting a bypass hole on th...

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Problems solved by technology

[0004] Although the above-mentioned single-stage variable capacity compressor in the prior art can realize the change of displacement, its energy efficiency is still low under harsh working conditions such as ultra-low temperature, and its working condition adaptability range is narrow

However, the volume ratio of ordinary two-stage enthalpy-increasing compressors cannot be adjusted, resulting in poor adaptability to operating conditions. The energy efficiency will drop sharply again, and the two cannot be balanced

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