This paper presents the results of a study designed to quantify the performance of water heaters insulated with polyurethane foams using three different blowing agents-hydrochlorofluorocarbon R-141b, H 2 O/CO 2 , 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 deter-mine the influence of the blowing agent on the water heater's energy factor and overall heat loss area coefficient. 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.

Also paper MN-00-15-1, in MN-00-15, Symposium on Ownership Costs and Test Results for New Residential Water Heating Systems

Units: Dual