Research On Vapor Injection Technology For Single Cylinder Rotary Compressor

As a clean and high-efficiency heating technology,heat pumps have attracted extensive attention.And air source heat pump with rotary compressors has become a first choice of technology as such advantages as better economy and higher efficiency.However,when an air source heat pump operates under lower ambient temperature,the system would show a degraded heating performance and insufficient heating capacity.At present,a satisfied solution to the problem of the poor performance operating under widely varying conditions for air source heat pump still was not proposed.Focusing on air source heat pump of full-year high efficiency is considered as a critical way to promote the clean heating in cold regions and also has an important significance to meet the great demand in China.Therefore,the thesis attempts to find an air source heat pump with a rotary compressor which can satisfy the heating request under low temperature and meanwhile can guarantee the satisfied performance for the whole year through utilizing the vapor injection technology.Given this,a comparably deep research for rotary compressor coupling with vapor injection technology has been conducted and the main work can be summarized as follows.First of all,the drawbacks for the traditional vapor injection rotary compressor has been analyzed according to the geometric characteristics of rotary compressors.Based on verified models,the analyzed problems for traditional vapor injection technology system has been studied.Through quantitative and qualitative methods,the fundamental reasons of poor performance for traditional quasi two-stage system has been discussed and revealed deeply.Second of all,a novel end-plate vapor injection structure with an injection valve for rotary compressor has been proposed.Utilized the geometric and analytical methods,the general formula for the envelope curve and injection area of the eligible injection area has been deduced and an optimized research has been carried out.Based on the principles of the novel end-plate injection structure,a prototype has been realized and experimental researches have been conducted.The experimental results indicated that the rotary compressor with the novel end-plate injection can achieve a greater injection mass flowrate and substantial improvement in heating capacity.Thirdly,a novel vapor injection structure on the blade for a rotary compressor has been proposed.Based on the dynamic analysis of compressor and the movement characteristic analysis of blade,the prototype of the rotary compressor with the novel blade injection has been processed and the experimental studies have been finished.The results implied that the rotary compressor with blade injection has a better performance over the regular rotary compressor and a competitive performance compared to the twin rotary compressor.Finally,establishing the simulation platform suitable for air source heat pumps with single-stage rotary compressor,traditional quasi two-stage rotary compressor,novel quasi two-stage rotary compressor and twin rotary compressor and finishing the component and system verifications.Based on numerical models,the performance and comparative researches for air source heat pumps coupling with the novel end-plate injection and blade injection has been implemented.The results suggested that the proposed quasi two-stage rotary compressors have an outstanding performance and can be considered as a substitute for the two-stage rotary compressor.