Experimental and analytical examination of the effect of double skin facade system on building thermal performance

Double skin facade systems are technology applied to the building envelope, which has a large share in building energy consumption, to provide indoor comfort conditions and energy efficiency. These systems enable natural or/and mechanical ventilation and lighting while increasing the sound insulation of the building envelope. The heat transfer in these systems, which are formed by integrating a secondary facade to traditional single facade systems by leaving an air cavity, becomes complex due to air movement in the interstitial spaces. In this study, heat transfer in conventional single skin facade and double skin facade system was studied experimentally and numerically by using one dimensional time dependent steady state approach and the effects of facade systems on building energy performance especially heating energy was investigated. In this context, a mathematical model considering user behavior and window aluminum frame element effect was build by zonal analysis method to calculate the heat transfer in single and box type closed cavity double skin facade systems, and build model has been experimentally verified. Experimental study was conducted in office spaces having single and double skin facade system in Ege University Civil Engineering building south facade in January 2017. Next, verified model was used to study the heat transfer in facade systems from two different climatic zones with the monthly average daily time periods. The change in thermal performance of single and double skin facade systems due to climatic condition during a year was investigated by using the 10 year average climate data of İzmir (Mediterranean climate) and Erzurum (Continental climate). According to the results, it has been found that double skin facade systems act as an insulator preventing extreme indoor temperature values, thus contributing to indoor comfort against changing external conditions. Although it is determined that the solar heat gain reduced about 17% by using double skin facade, compare to single facade heat losses can be reduced 39% in continental climate and heat gain in heating period can be increased 64% in mediterranean climate. Keywords: Double skin facade, closed cavity, heat transfer, energy efficiency in buildings.