Thermal performance of reflective insulation system and comparison against ASHRAE Standard

Abstract

The trend in building energy consumption has been steadily increasing and will continue to rise significantly in the future. The application of a reflective insulation system in roof assembly is proven to be effective in reducing heat gain across the roof and can enhance indoor thermal comfort. This paper presents the development of an Indoor Solar Simulator to evaluate the thermal resistance (RSI value) of reflective insulation systems for roof assemblies. This paper also compares RSI values obtained experimentally and the RSI values listed in ASHRAE Standard. The roof assemblies studied in this paper incorporate the same reflective insulation systems as listed in ASHRAE Standard. Thermocouples and heat flux transducers are installed at various locations and the RSI values are calculated using the average method as detailed in ISO 9869-1:2014. From the error analysis, it can be concluded the RSI values obtained experimentally using the Indoor Solar Simulator and ASHRAE Standard are in a good agreement with MAPE value of 6.13%. These discrepancies could be due to the thermal bridges from mechanical supports inside the air gap, or possibly the air gaps are not completely airtight and unventilated.