Development and evaluation of a measurement method and system for solar heat gain coefficient and thermal transmittance

Abstract

Evaluation of the thermal performance of a fenestration system during the cooling season is based on heat gains by temperature difference and solar radiation, characterised by thermal transmittance (U-value) and solar heat gain coefficient, respectively. While U-value testing and calculation methods have been long established, solar heat gain coefficient has been evaluated only by calculation under the lack of any established testing method. However, calculation alone cannot yield exact solar heat gain coefficient values for various types of fenestration. To address this problem, this study aims to develop a solar heat gain coefficient apparatus for measuring the energy performance of fenestration in terms of U-value and solar heat gain coefficient, and to evaluate that system. The proposed measurement system can be used in measuring U-values and solar heat gain coefficient values for fenestration with complicated shapes, such as an awning device.