Field evaluation of the performance of a radiant heating/cooling ceiling panel system

For testing different engineering solutions for energy-efficient buildings, a low-energy building was built at the University of Tokyo as a pilot project. In this building, a radiant heating/cooling ceiling panel system is used. This study aims to not only clarify the system performance but also to share our experience and results for them to serve as a reference for other similar projects. Here, the system performance in relation to its heating/cooling capacity and thermal comfort has been evaluated. The heat transfer coefficient from water to room was 3.7 W/(m2K) and 4.8 W/(m2K) for heating and cooling, respectively. The thermal comfort measurement showed that the air and operative temperature distributions in the room were highly uniform. In both heating and cooling, the PMV was higher than - 0.5 and less than +0.5 and the PPD was less than 10%. A category B thermal environment was obtained using the radiant ceiling heating/cooling system.