Thermal Resistance of 30° Sloped, Enclosed Airspaces Subjected to Upward Heat Flow

Heat transmission across an enclosed space is determined by the type of filling gas, temperatures and long-wave emissivities all surfaces that define space, heat flow direction. The ASHRAE Handbook Fundamentals provides thermal resistances (R-values) airspaces with only five effective emittance values (E) for vertical, horizontal, 45° airspaces. R-values do not include case 30° sloped In addition, ignore impact airspace aspect ratio (A) on R-values. However, many previous studies, as well this study, have shown A can a significant effect R-value. Previously, correlations were developed determining vertical (90°) subjected to horizontal flow, (0°) up down downward flow. To authors’ knowledge, no such correlation existed R-value upward which in paper. potential increase placing thin layer varied both sides middle was also considered. Architects building designers use compute various E operating conditions. This along be included current energy models (e.g., EnergyPlus, ESP-r, DOE, Design Builder).