Theoretical and experimental study on total heat recovery from flue gas of gas-engine heat pumps coupled with condensing gas boilers
Liu Fengguo[1] Wu De[1] Wu Hubiao[1] Jia Leilei[2] Gong Weiyuan[2]
In order to achieve the goal of fully recovering the condensation latent heat from the flue gas of gas boilers, this paper proposes to use a cast silicon-aluminum heat exchanger for flue gas waste heat recovery, and couple it with a gas-engine heat pump unit to recover the total heat from the low-temperature flue gas of condensing gas boilers. An experimental platform for the coupled unit is established to conduct experimental research on the waste heat recovery effect of the flue gas. The operating performance of the coupled unit under different inlet water temperatures of the flue gas waste heat recovery heat exchanger and different boiler load rates is analysed, and the economy of the unit is analysed. The results show that when the inlet water temperature of the flue gas waste heat recovery heat exchanger is 14 to 20 ℃, the total heating capacity of the coupled unit remains stable at about 645 kW, the thermal efficiency is about 110%, and the payback period for the initial equipment investment is about 1.9 heating seasons.