TY - JOUR
TI - Influence of water supply temperature on the heating characteristics of low temperature air source heat pump water heaters
AU - Cao Kan
AU - Tan Zezi
AU - Kang Zhiwei
AU - Yu Bowen
AU - Ma Wannian
AU - Liang Jiaxing
AU - Yuan Yaohua
JN - Thermal Science
PY - 2025
VL - 29
IS - 3
SP - 1999
EP - 2006
PT - Article
AB - One of the inherent limitations of air source heat pump water heaters is  their reduced performance when the external temperature is low. In order to  investigate the impact of water supply temperature on system heating in low  temperature conditions, a test bench for an air source heat pump water  heater with a medium pressure air supply was constructed. The findings  illustrate that within the two low temperature settings of -7°C and -15°C,  the heating capacity of the system initially increases with the rise in  water supply temperature, reaching a peak at 39°C. However, this effect is  not sustained as the temperature of the water supply continues to rise.  Concurrently, the system's heating capacity reaches its maximum at a water  supply temperature of 39°C. At this temperature, the heating capacity is  45.8% lower than at -7°C, the compressor power is 42.1% lower, and the  system coefficient of performance is 7.2% lower.