Variable-displacement-ratio double-stage compression air conditioner system and control method thereof

Abstract

The invention provides a variable-displacement-ratio double-stage compression air conditioner system and a control method thereof. The variable-displacement-ratio double-stage compression air conditioner system comprises a variable-displacement-ratio double-stage compressor (1). A low-pressure suction pipeline (2), a high-pressure exhaust pipeline (3) and a capacity-variable pipeline (4) are arranged on the compressor in a connected mode. Low-pressure stage double air cylinders of the double-stage compressor are made to operate by introducing high pressure into the capacity-variable pipeline (4), and one low-pressure stage single air cylinder of the double-stage compressor is made to operate by introducing low pressure. Switching control over the displacement ratio can be realized by introducing high pressure or low pressure into the capacity-variable pipeline, switching control over the displacement ratio is carried out through the above ways according to the indoor unit capacity requirement and overall load, the air conditioner system operates in a large displacement mode when the load is small and operates in a small displacement mode when the load is large, and the operating efficiency of the system is maximized, so that the technical problem of poor economy existing when the load is too small or too large is solved.

Description

technical field [0001] The invention belongs to the technical field of air conditioning, and in particular relates to a variable displacement ratio two-stage compression air conditioning system and a control method thereof. Background technique [0002] In the prior art, the lower the ambient temperature, the greater the demand for the heating capacity of the air conditioner, but the current single-stage compression heat pump can only start and run normally at minus 20 degrees, and the heating capacity is seriously attenuated, the heating effect cannot be guaranteed, and the unit is reliable Sex is also severely tested. [0003] Compared with single-stage compression heat pumps, the two-stage compression system with air injection enthalpy increases the heating capacity at low temperatures and has higher energy efficiency. And the two-stage compression system can reduce the pressure ratio of the single-stage compressor, lower the exhaust temperature, and at the same time imp...

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Problems solved by technology

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the disadvantage of poor economy of the air conditioning system in the prior art when the load is too small or too large, thereby providing a variable displacement ratio two-stage compression air conditioning system and its control method

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