Investigation of the Turbulent Flow Behaviour in a Transpired Air Collector

There is an increasing interest in developing renewable energy systems to address the increasing global energy demand and fight climate change. One emerging technology is the transpired air collector, which is a unique type of corrugated and perforated sheet metal installed in front of a building to absorb incident sunlight to preheat the building air intake. As the airflow behaviour in the channel influences the air heat gain, it is important to understand the fluid dynamics within the transpired air collector to maximize its efficiency. A full scale experimental setup using a commercial transpired air collector was built in a laboratory environment. Particle Image Velocimetry (PIV) was used to measure two-dimensional velocity fields at different air flow rates and at different locations inside the channel. PIV data were used to compute various turbulent characteristics of the air flow. It was found that the mean velocity peaks tended towards the flat construction wall side. The profiles of the Reynolds stress indicated a significant momentum transfer from the corrugation wall by the turbulent velocity field towards the bulk flow. Results demonstrate that the turbulence produced by the corrugation waveform dominates the entire channel.