Improving thermal and combustion efficiency of gas water heater

The traditional tank type water heaters have thermal and combustion efficiency of the order of 35% and 67.4% respectively. These efficiencies can be improved through various alterations. The factors, Turbulence, Temperature, Time (3 Ts) have been identified to improve heat transfer. The water heaters combustion efficiency, thermal efficiency, recovery rate and draft were determined for a typical set of water heaters. The experimental investigation was carried out by introducing various types of baffles in the flue pipe e.g. flat, conical, finned and barbed razor wire. It was observed that these design improvements resulted in the performance enhancement significantly. The reason attributed to this achievement is increased retention time of flue gases, reduction in temperature of the exhaust gases and rapid turbulence in exhaust pipe. It is observed that barbed razor wire baffle is the best amongst the options studied. The combustion and thermal efficiency in this case improved from 68% to 88% and 35% to 67.4% respectively. (C) 2011 Elsevier Ltd. All rights reserved.