NO-94-14-4 -- Measurement of the Exterior Convective Film Coefficient for Windows in Low-Rise Buildings PDF

The MoWiTT field facility was used to measure the convective film coefficient over the exterior surface of a window. The measured data are compared to some commonly used experimental and theoretical models. The comparison shows that the measured data disagree with previously used models, such as the ASHRAE/DOE-2 model. The reasons for these disagreements are discussed. An experimental model, based on the MoWiTT measured data, is presented to correlate the film coefficient with the difference in temperatures of the exterior glass surface and the ambient in the natural convection region and with the site wind speed in the forced convection region. The wind speed is considered both in windward and leeward hemispheres. The validity of the MoWiTT experimental model for low-rise buildings is discussed.

KEYWORDS: measuring, windows, window films, glazing, surface area, buildings, comparing, calorimeters, experiment, accuracy, calculating, heat flow, temperature difference, ambient temperature, wind speed, heat balance, temperature.