A state of art review on methodologies for heat transfer and energy flow characteristics of the active building envelopes

Significant share of total final energy use is accounted by the building sector in most of the countries around the world. One way to reduce building energy consumption is to adopt energy efficiency technologies and strategies. Due to environmental concerns and high cost of energy in recent years there has been a renewed interest in building energy efficiency and integration of renewable energy technologies. Active building envelope technology, i.e. transpired solar collectors (TSCs), provides a cost-efficient way of minimizing energy demand of buildings in accordance with global principle of sustainability, which has also proven reliable for diverse applications such as preheating fresh air delivery into the buildings and supplying domestic hot water in summer etc. The objective of this paper is to review the heat transfer and energy flow characteristics of the active building envelopes, particularly focusing on various types of TSCs. Present work consists of background and concept of TSCs, research literature for thermal performance, theoretical modelling, experimental study and numerical simulation investigation. Diverse mathematical models, including thermal models, air flow models, porosity models, and turbulence models etc., have also been presented and compared. Following that, more than 20 parameters affecting TSC performance have been analyzed and evaluated. The literature has illustrated that the best overall performance of turbulence model is RNG k-ε the effects of those parameters on TSC efficiency are completely different, depending on local climatic conditions, time and site constraints, and the interaction between different factors.