Experiments and computer simulations were conducted to evaluate the performance of radiant barriers under three different insulation levels in residential applications. The experiments were conducted in central Texas, USA using side-by-side comparisons in which two houses, with identical floor plans and thermal profiles, were used. The houses were instrumented, calibrated, and their heat transfer rates across the ceilings were measured and recorded. A heat and mass transfer model was used to run the computer simulations.
A simple duct system was installed in an attic test module for a large-scale climate simulator at a U. S. national laboratory. The goal of the tests and subsequent modeling was to develop an accurate method of assessing duct system performance in the laboratory, enabling limiting conditions to be imposed at will and results to be applied to residential attics with attic duct systems. Steady-state tests were done at a severe summer condition and a mild winter condition. In all tests the roof surface was heated above ambient air temperatures by infrared lights.
During the cooling season, heat transfer from the attic into the conditioned space of a residence can represent a significant portion of the total envelope heat transfer. Radiant barriers are one method used to reduce this heat transfer. A quasi-steady-state model was developed or predicting attic heat transfer in residences with radiant barrier systems. The model was used to estimate the reduction in cooling load that would occur with a radiant barrier and to identify important construction and environmental parameters that influence this cooling load reduction.
Ventilation of the void below suspended timber floors is necessary to prevent dampness, which leads to wet and dry rot. The air flow beneath such a floor has been investigated for a range of ventilator hole positions, using a full-sized test room. The variations in heatlosses with ventilation rate have been measured, for floors with and without insulation. The use of radiation barriers in place of conventional thermal insulation was found to cut down the heat losses significantly at low ventilation rates, but was not so effective at higher rates.
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