Thermal Performance of Gas-Filled Panels with Reflective Surfaces Installed in an Attic PDF

The thermal performance of gas-filled panels (GFPs) with internal and external reflective surfaces were measured in the Large-Scale Climate Simulator (LSCS) at Oak Ridge National Laboratory. Prototype panels filled with argon and panels filled with air were evaluated for both winter and summer conditions. The nominally 1.5 in. (38.1 mm) thick GFPs were installed on top of 3.5 in. (88.9 mm) thick nominal R-13 (RSI-2.29) fiberglass batts to simulate retrofit attic insulation installation. Analysis of the experimental results provided the thermal resistance of the batts, the thermal resistance of the GFPs, and the radiant barrier contributions to the overall thermal resistance between the attic floor and the roof sheathing.

The total contribution of the GFP layer installed above fiberglass batt insulation was 5 to 6 ft²·h·°F/Btu (0.88 to 1.06 m²·W/K) for winter conditions with an outside temperature of 25°F (–3.9°C) and an inside temperature of 70°F (21.1°C). The GFPs added 12 to 13 ft²·h·°F/Btu (2.11 to 2.29 m²·W/K) to the attic thermal resistance with an outside temperature of 115°F (46.1°C) and a roof sheathing temperature of 150°F (65.6°C) due to simulated solar radiation. The summer radiant barrier contribution to the attic thermal resistance was about 6 ft²·h·°F/Btu (1.06 m²·W/K) for both the argon-filled and airfilled GFPs. This project included 11 steady-state LSCS measurements (ASTM 2006a) complemented by material R-value measurements made with a heat-flowmeter apparatus (ASTM 2006b).

Presented at Thermal Performance of Exterior Envelopes of Whole Buildings X – December 2007

Units: Dual