| Due to the high primary energy utilization rate,almost no environmental pollution and the unique advantages of refrigeration and heating,the air source heat pump system has a good promotion and development prospect under the overall policy orientation of clean energy.However,due to the heating operation of the heat pump unit under low temperature and high humidity conditions,the surface of the fin of the outdoor unit heat exchanger is easily frozen due to low temperature,and the outdoor heat exchanger is aggravated as the freezing phenomenon continues to increase.The fin gap is gradually blocked,the air flow is blocked,making it difficult for the fin to exchange heat with enough air,which causes the overall coefficient of performance of the unit to be continuously reduced.Finally,the heat pump unit has no heating capacity due to almost no heat exchange..Therefore,in order to ensure the continuous low-temperature heating capacity of the heat pump unit in winter,the heat pump unit must be defrosted regularly.At present,the research direction of frosting of heat pump heat exchangers is mainly divided into active defrosting technology and passive defrosting technology.In this paper,based on the characteristics of active and passive defrosting defrosting technology research and analysis,put forward a kind of super hydrophobic electro-thermal coating composite defrosting method,not only the material of super hydrophobic combined with electric heat defrost mode,to make up for the high energy consumption of the electric heating defrosting and super hydrophobic surface can only delay the defects of frost,based on the super hydrophobic graphene and excellent electrical conductivity graphene electro-thermal coating epoxy resin was prepared by heat exchanger.First of all,through the experimental determination of the roughness of the coating for heat exchanger fin,contact Angle and surface energy and comparative analysis the content of graphene graphene composite coating of epoxy resin was evaporator hydrophobic properties,the influence of the simulation experiment results concluded on the basis of analysis and discussion,increase the amount of graphene conductive filler can enhance after graphene cream suppression effect of epoxy resin composite coating.And epoxy resin + 2 wt % and 4 wt % graphene coating on the electrothermal characteristics and resistance stability test,the test results show that increasing the content of graphene in the composite coating can enhance the stable temperature rise rate and the final temperature of coating,the epoxy resin + 4 wt % graphene coating would be under more than 20 v voltage as the coating surface temperatures eventually lead to deformation and failure.Of graphene composite coating epoxy resin + 2 wt % and traditional electric heating defrosting process simulation analysis,analysis of epoxy resin of super hydrophobic graphene coatings combined with planar heating advantage after frost/defrost suppression effect is obvious,than traditional electric heating wire defrosting defrosting time is significantly shortened,the comprehensive analysis of the results,the use of super hydrophobic properties of graphene coating epoxy resin and defrost effectively combine with air source heat pump system can reduce the defrosting frequency unit,improve the low temperature heating and stable operation of the defrost efficiency and system capacity,not only can reduce energy consumption effectively defrost,It can also improve the continuous heating capacity of air source heat pump unit in winter. |
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