Experimental research and energy consumption analysis on the economic performance of a hybrid-power gas engine heat pump with LiFePO4 battery

Abstract Hybrid power gas engine heat pump (HPGHP) is a novel air conditioning system that uses a power battery as an auxiliary power source to achieve efficient engine operation. Considering that frequent changes in external load can cause frequent charge/discharge of the battery and adversely affect energy conversion efficiency, lithium iron phosphate (LiFePO4) battery was used as the auxiliary power source to analyze its economic performance. A dynamic energy control strategy based on engine economic zone and battery status was proposed to realize power distribution between gas engine and electric motor. By analyzing the fuel consumption rate, energy conversion efficiency and energy consumption, the superior performance of the LiFePO4 battery HPGHP was confirmed. Test results show that the minimum gas consumption rate of LiFePO4 battery HPGHP under low-load, medium-load and high-load conditions was 12.2%, 1.07%, and 6.54% lower than that of lead-acid battery HPGHP. Equivalent energy conversion efficiency was about 7.03%, 0.98%, and 10.42% higher than lead-acid battery HPGHP, 18.56%, 1.98%, and 27.2% higher than conventional GEHP. In addition, energy consumption analysis indicates that the annual primary energy rate (PER) of LiFePO4 battery HPGHP was about 39.85%, 28.35%, and 8.4% higher than electrical heat pump (EHP), GEHP and lead-acid battery HPGHP.