Heat pumps with rotary compressors operating in low temperature ambient will face heavy performance degradation. A novel vapor injection structure on the blade for the rotary compressor has been proposed in this paper to overcome the back-flowing drawback of the traditional cylinder injection structure and enlarge the injection area. Based on a verified numerical model, the performance of a rotary compressor with the blade injection structure has been investigated. The results indicate that: the proposed vapor injection structure can eliminate the back-flowing of the injected refrigerant; compared to the traditional injection structure, the new structure can enhance the volumetric efficiency and injection mass flow-rate by 1.8~2.7% and 26.6~57.2%, respectively; and compared to the traditional injection structure, the new structure can increase the heating capacity and COP by 23.1~48.9% and 3.2~8.0%, respectively.

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Economizer technology has become a critical method to improve the performance of air conditioners with rotary compressor in low ambient temperature. A novel vapor injection structure on the blade of the rotary compressor has been proposed in previous research to overcome the drawback of the traditional cylinder injection structure. Based on a verified numerical system model, the performance of an air conditioner adopting different economized rotary compressors has been investigated. The results indicate that: compared to the single cylinder rotary compressor with traditional injection structure, the rotary compressor with blade injection structure can enhance the heating capacity and COP by 12.9%~15.7% and 1.5%~4.1% in low ambient temperature, respectively. And compared to the twincylinder rotary compressor, the rotary compressor with blade injection structure has a competitive performance.

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