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Thermal Performance of Residential Electric Water Heaters Using Alternative Blowing Agents.


pdf icon Thermal Performance of Residential Electric Water Heaters Using Alternative Blowing Agents. (1923 K)
Fanney, A. H.; Zarr, R. R.; Ketay-Paprocki, J. D.

ASHRAE Transactions 2000, Vol. 106, No. 2, 1-13, July 2000.

Keywords:

water heaters; blowing agents; efficiency; insulation; heat loss; residential buildings; thermal conductivity

Abstract:

This paper presents the results of a study designed to quantify the performance of water heaters insulated polyurethane foams using three different blowing agents -- hydrochlorofluorocarbon R-141b, H2O/C02, and hydrofluorocarbon R-245fa. The thermal conductivity of the foam was measured as a function of mean temperature, using a guarded hot plate apparatus. Electric residential water heaters, insulated with the three polyurethane foams, were tested to determine the influence of the blowing agent on the water heater's energy factor and overall heat loss area coeficient. A relationship between the overall heat loss area coefficient and energy factor was developed and compared to experimental results. An infrared imaging system revealed that areas surrounding the heating element access covers, the lower circumference of the water heater and piping penetrations were significantly higher in temperature than the exterior surface of the water heater.