Abstract: Users are accustomed to switching off the heat pump unit during the day and switching on the heat pump unit at night during the transitional season when heating is required, and such usage habits make the study of the frequency control strategy of the heat pump switch-on phase particularly important. In order to study the difference between the room temperature rise effect and power consumption under different switch-on frequencies, found that under the same test conditions, by comparing the operating effect of the unit under the initial frequencies of 80 Hz and 68 Hz, the indoor temperature rise effect of the two schemes is comparable, but the power consumption of the 68 Hz operating frequency is reduced by 14% compared with that of 80 Hz in 1 h. Through the time-by-time data comparison, it was found that the water temperature grows too fast is the main reason for the high energy consumption of high-frequency start-up operation, which leads to the conclusion that the frequency control in the start-up phase needs to be correlated with the rate of water temperature growth. The results of this experiment can provide a reference for the optimisation of the start-up frequency control strategy of heat pump units.

Key words: Heat pump, Frequency control, Energy conservation