To solve the problems of complex structure and unsuitable capacity control of present multi-function heat pump system
domestic energy system is introduced. A new system performance indicator is chosen to describe the performance of space cooling & water heating mode. By comparison with space cooling only mode
this mode has been proved with a little less cooling capacity but with higher total system performance. Series of experiments are conducted with different initial water temperature in tank
compressor load and outdoor ambient temperature conditions. By analysis of transient characteristics and system performance
the performance rules are concluded. Furthermore
the control strategy is proposed to insure the safe and efficient operation of space cooling & water heating mode.