Research On Defrosting Control Method Of Air Source Heat Pump Based On Image Processing Technology

In recent years,Beijing-Tianjin-Hebei and other regions have introduced a number of measures to change the energy used by heating from coal to electricity and gas,which aims to adopt the use of clean energy instead of decentralized coal heating to avoid environmental degradation problems.The air source heat pump technology,which has the advantages of high energy utilization and non-pollution,has been used more and more widely.But the frosting problem of outdoor heat exchanger affects the operation efficiency of air source heat pump in winter,so the effective defrosting is very important.On the basis of summarizing the development and research status of air source heat pump defrosting at home and abroad,this paper puts forward a control method of defrosting air source heat pump based on image processing technology,and tests the defrosting control method to verify the feasibility of the method.Firstly,this paper describes the formation of frost layer on fin surface and its growth mechanism.Based on the simplified model of fin surface frosting and the heat and mass transfer theory,the mathematical model of fin and frost layer is established,the heat balance equation of each control body is obtained,and the equation is discretized and solved.It lays a theoretical foundation for studying the dynamic change of frost layer during defrosting.Secondly,based on the application of the existing image processing technology,the air source heat pump defrosting control method is developed,and the determination of defrosting and stopping is obtained through the processing of the image collection,pretreatment,multi-threshold segmentation and information feature discrimination of fin surface frosting.The coefficient P of frosting on fin surface of outdoor heat exchanger is introduced to characterize the degree of frosting on fin surface,thus the requirement of defrosting control is quantified.The experiment environment room was constructed,and the phenomenon of defrosting not timely and frost-free defrosting was analyzed.Finally,based on the above methods,the new defrosting control method is tested under two working conditions.On the other hand,the coefficient P value of frost degree of fin surface is set at 0.5 and 0.08 as the judging condition of defrosting and stopping,the feasibility of the defrosting control method is verified,and the method can realize the frost-removing according to the conventional defrosting control method.The research of this paper provides a new solution for the research of air source heat pump defrosting control method,and the new method can realize the aim of defrosting,which provides the theoretical basis and technical reserve for further research.