Evaluating thermal performance of double-skin facade using response factor

Abstract

Modern office buildings frequently adopted Double-skin façades (DSFs) to save energy use for heating and cooling. The operable layers of a DSFs are designed to control the heat and airflow in its flow domain. The dynamic thermal properties of the operable layers should be well understood for the successful design of a DSFs. The objective of this study was to provide easy and reliable calculation method for cooling or heating load of a DSFs under dynamic weather conditions. The heat transfer in the operable layers was expressed by using the response factor which was got from field monitored data as a transfer function of incident solar radiation and exterior surface temperature at the inner glass of a DSFs. The proposed model was validated by the energy simulations with TRNSYS and field monitoring conducted during 35 days in summer, 6 August to 9 September 2012. From the results, it was found that the response factor is a very useful index to predict the thermal performance of a DSFs. The exterior surface temperature of the DSFs predicted by the response factor was fitted well with the field monitored data in both blind rolling and rolling off conditions. The mean bias error (MBE) and root mean square error (RMSE) of the predicted temperature were within 1.5% and 2.1%, respectively. The models can be helpful to evaluate the thermal performance of DSFs at the early building design stage.