Hydronic flow path analysis on the thermal comfort performance of radiant cooling system

Abstract

Construction and operation in the building sector account for more than 1/5th of global energy consumption. Moving on to an energy-efficient cooling technology and eco-friendly building material can lead to energy savings and a reduction in associated CO2 emissions. In the present study, an energy-efficient thermally activated building system (TABS) is integrated with eco-friendly building material, namely, glass fibre reinforced gypsum (GFRG). The proposed hybrid system is termed as thermally activated glass fibre reinforced gypsum (TAGFRG) system. This system is not only energy-efficient and eco-friendly but also provides better thermal comfort. An experimental room is constructed with the TAGFRG roof within the Indian Institute of Technology Madras campus, Chennai, i.e., in a tropical warm and humid climate zone. The TAGFRG roof has reinforcement in every third cavity with cooling pipes, while in the other two cavities, cooling pipes are embedded with air gap and partial reinforcement. The TAGFRG roof has four parallel loops of cooling pipelines, and each loop consists of one reinforcement zone (RZ) and two air gap zones (AZ1 and AZ2) in series. According to the water flow path in a single loop, various combinations of the flow path, i.e., RZ → AZ1 → AZ2, AZ1 → RZ → AZ2 and AZ1 → AZ2 → RZ, have been analyzed. According to the adaptive thermal comfort model, the water flow path has a negligible effect on thermal comfort. The average operative temperature for all the cases investigated varies between 28.1 and 29.2 °C. The operative temperature is always within the 90% band of thermal comfort, as per the adaptive comfort model.