机组冷却器表面结霜，如果不定期清除，最终将导致机组性能受损，最终使其无法使用。因此，在冰点以下的空间，有必要提供外部热源，以充分加热装置，融化霜冻并清除霜冻。在大型中央设备型系统中，最常用的供热方法是从制冷系统的高压侧进行，称为热气除霜。尽管这样收集的用于融化霜冻的热量会在系统外部被拒绝，但除霜过程并非免费。与该过程相关的重大损失迄今尚未完全确定。本文研究了大型商用冷冻机热气除霜过程中的传热传质和流体流动机理。 它提出了一些数学模型来分析这一现象，并提供了诺模图来估计产生的制冷负荷和相关成本。引用:研讨会，ASHRAE Trans。，第95卷，第。2.

The build-up of frost on unit cooler surfaces, if not periodically cleared, will eventually cause impairment of the unit’s performance, eventually rendering it useless.Thus it is necessa~ in spaces below freezing, to provide an external supply of heat to warm the unit sufficiently to melt the frost and remove it. In large central-plant-type systems the most common method employed for supplying heat is from the high-pressure side of the refrigeration system, referred to as hot gas defrost.Although the heat thus captured for use in melting frost would otherwise be rejected external to the system, the defrosting process is not free of cost. There are significant losses associated with the process the magnitude of which have not heretofore been fully identified.This paper looks at the heat and mass transfer and fluid flow mechanisms involved in the hot gas defrost process in large commercial freezers. It suggests some mathematical models for analysis of the phenomenon and offers nomographs for estimating the resultant refrigeration loads and associated costs.