Advances in frosting suppression air source heat pump device: definition and classification

It has been known that space heating air source heat pumps (ASHPs) are energy-saving, low-carbon, and popular worldwide. The combination of low-temperature and high humidity can lead to frosting formation on the outdoor coil surface, resulting in a low operating coefficient of performance. However, there is no definition and classification of frosting suppression ASHP devices, resulting in a slow development of frosting suppression technology. Therefore, this paper defines and classifies frosting suppression ASHP devices to address the gap. Firstly, several parameters to describe the frosting suppression performance of the ASHP device were defined. Secondly, the experimental platform, unit, and operating conditions were set up in detail. Thirdly, the definition and classification for frosting suppression ASHP devices were established. It is shown that when the output heating capacity decay rate during frosting (Ɛ_f) reaches 5 %, if the corresponding time (t_f) ≥ 68 min, is a frosting suppression ASHP device. Furthermore, if t_f > 96 min, is a first level frosting suppression performance; if 68 ≤ t_f ≤ 96 min, is a second level. At the same time, the frosting suppression device can improve energy efficiency by up to 78 %. The result could offer practical guidance for equipment manufacturers to enhance the frosting suppression performance, and lay a foundation for developing Chinese standards for frosting suppression ASHP devices.