Research status of dust accumulation characteristics and dust removal methods of outdoor heat exchangers of air-source heat pumps

The phenomenon of dust accumulation in the outdoor heat exchanger of air-source heat pumps is focused, and the impacts of different factors on the dust accumulation degree and the system operation are summarized in this paper. Based on the analysis of the mechanism of dust accumulation, it is found that there are two main factors that affect the dust accumulation characteristics of heat exchangers: internal factors (fin structure, fin spacing, tube row number) and external factors (operating condition, air flow rate, particle size and concentration, particle type). This paper summarizes the current main dust removal methods and concludes that the dust removal technology by frost formation and defrosting is relatively economical and effective. It is necessary to study the microscopic characteristics and mechanisms of frost formation and defrosting processes in heat exchangers under dust accumulation conditions, as well as the flow mechanism of the dust layer carried by the frost layer during defrosting and dust removal, in order to provide support for the future research and development of advanced technologies to inhibit the growth of dust on the surface of heat exchangers and dust removal.