This paper evaluates the seasonal thermodynamic efficiency of the air-to-air heat pump used for a heat recovery ventilation system and several modulations of compressors affecting the thermodynamic efficiency of the heat pump. A variable speed and on/off-type compressors have been selected. In order to evaluate the thermodynamic potential of the device, energy analysis has been performed. Along with modelling the operation of the air handling unit during the cold time of the year, variations in the thermodynamic efficiency or different modulation compressors have been compared. The obtained results have shown that the use of a few simple compressors causes a decrease in the seasonal parameters of the heat pump: heat generated by a condenser is 5% lower compared to the use of variable speed compressors and therefore the seasonal coefficient of the performance (COP) of the heat pump decreases by 5%. Possible improvement on the heat pump can be provided changing the compressor into variable speed or modulatory equipment, which allows adjusting to heat demand and thus increases the seasonal efficiency of the system from a thermodynamic point of view.

Article in Lithuanian