Experimental study on the enhancement of the thermal efficiency of a household gas water heater

In this paper improvement of efficiency of a household gas water heater has been investigated experimentally. For this purpose, six baffles have been used for deceleration of the hot exhaust gases in the middle tube of the water heater. Three of the baffles have almost the same geometry and dimension and the other three are different from geometry and dimension points of view. Also the same distances between the baffles have been considered. The geometry and dimension of the baffles have been chosen by experimental tests. Experimental results show that by employing the optimum geometries and dimension of the baffles and by selecting the optimum arrangement of the baffles, the thermal efficiency of the household gas water heater has been improved and increased up to 82.5 percent. Experimental results also show that by improvement of the thermal efficiency of the household gas water heater, pollutant emissions which have been measured by the gas analyzers at the laboratory remained almost at the lowest level. Finally by taking into account the effective parameters on the uncertainty for the thermal efficiency, in terms of the level of almost 95 percent for insurance against the reported number for the efficiency, the total uncertainty of the final optimized model for the thermal efficiency is ± 0,17.