The effect of the District Heating Return Temperature Reduction on Flue Gas Condenser Efficiency

The use of flue gas condensers proved to be effective in increasing boiler efficiency and achieving primary energy savings. The transition to the 4^th generation district heating will lead to temperature reduction in district heating networks. The aim of this study is to determine the effects of the reduction in the district heating return temperature on flue gas condenser efficiency. Different DH return temperatures and fuel moisture contents were examined, and a calculation model was created. The results show that a reduction in district heating return temperature can lead to an increase in heat recovery through the flue gas condenser. Primary energy savings were estimated based on the amount of heat recovered.