Research on defrost characteristics of cascading high temperature air source heat pumps

Abstract

There is a substantial demand for more efficient methods of reusing waste heat from manufacturing operations. Vapor compression technology is used to transform low-grade heat sources into high-temperature hot water, and subsequently water vapor compression technology is used to generate high-temperature steam. To achieve the required water temperature for the vapor compression system, a high-temperature cascade heat pump system is designed in this article. To achieve these requirements, the state point approach is used to design the system's operational parameters under maximum operating circumstances, and a suitable refrigerant is chosen in line with the performance coefficient of the cascade system. The high-temperature cascade heat pump system has a fin heat exchanger and an air heat exchanger on its low-temperature side. The low temperature side of the cascade system is designed to use a dual system mode to address the issue of the negative effect that system defrosting has on heat generation. This is done so that the desired demand for hot water may be met regardless of the actual temperature in the room. During this period, the theoretical calculation analyzes how changing the output water temperature and the surrounding temperature affects the rest of the system's characteristics. This provides strong theoretical backing for the smooth operation of the system.