空气源热泵室外换热器结霜、除霜及积灰特性研究现状与展望

Research status and prospect of frost,defrost and ash accumulation characteristics of outdoor heat exchanger of air source heat pump

空气源热泵由于其高效、节能环保受到广泛应用。但是,热泵机组运行过程中,积灰和结霜导致室外换热器换热热阻增大,换热效率降低,影响了空气源热泵机组的安全和高效运行,严重阻碍了其推广和应用。目前,学者们已对二者分别展开了广泛的研究,但对于其相互作用鲜有涉及。本文基于积灰、结霜的机理,综述了各自对系统运行性能的影响及除灰、除霜技术的发展,总结了积灰对结霜过程的影响及除霜过程对除灰的作用,提出目前有必要研究积灰条件下换热器结霜/融霜过程的微观特征及其机理,以及积灰对空气源热泵系统的结/融霜频率和系统性能的影响规律,研发针对积灰条件下除霜及抑霜的技术。

Air source heat pump is widely used because of its high efficiency,energy saving and environmental protection.However,during the operation of the heat pump u-nit,ash accumulation and frosting lead to the increase of heat transfer resistance of out-door heat exchanger and the decrease of heat transfer efficiency which has seriously hin-dered its popularization and application.At present,scholars have carried out extensive work on these fields,but their interaction mechanism between of them has been reported rarely.In this paper,based on the mechanism of ash accumulation and frosting,the influ-ence of them on the performance of air source heat pump system and ash removal and frosting technology are reviewed.Also the influence of ash accumulation on frosting process and the effect of defrosting process are summarized.It is pointed out that it is nec-essary to study the micro characteristics and mechanism of frosting/defrosting process of heat exchanger under ash accumulation condition,and the influence rule of ash accumula-tion on the frequency and system performance of air source heat pump,and to develop the defrosting and restrain frosting technology under ash accumulation condition.