Numerical and Experimental Investigation of Baffles Effect on Thermal Efficiency of Room Gas Heater

This paper presents a research on thermal efficiency of home gas heaters. Installing baffles inside the furnace and against hot product gas flow prevents rapid gas flow out of the chimney, causing to increase the residue time of flue gases. Therefore, instead of heat energy loss, the energy is transferred to the room, thereby increasing the thermal efficiency of the gas heater. On the other hand, installing these baffles increases pressure drop, which can cause incomplete combustion and pollutant formation. In this work, we used fluent software to simulate fluid flow and heat transfer of product gases for different suggested obstacle surface configurations, and studied its effect on the thermal efficiency of gas heaters. Obstacle configuration with the maximum thermal efficiency is determined, built in workshop, installed and tested experimentally and its performance is shown to correspond with the computer simulation. Ultimately, the thermal efficiency of the model 12000 of Donar-khazar gas heater increased from 76.2 to 82.9% using this model.