Field studies on the energy consumption and thermal comfort of a nZEB using radiant ceiling panel and open-loop groundwater heat pump system in a cold region

Abstract

Field studies were conducted in an office building in a cold region equipped with a radiant ceiling panel (RCP) and open-loop groundwater heat pump (GWHP) system. First, the indoor thermal comfort in a target office was evaluated based on the results obtained from the physical measurements and survey questionnaire. The results showed that the suspended RCP system could achieve comfortable indoor thermal conditions throughout the year. The indoor temperature was maintained within the range of 22–26 °C, the humidity was within 30–60%, and CO2 concentration was mostly below 1000 ppm. Second, the energy performance was tested simultaneously, and intermittent and continuous operation methods were compared. Under the continuous operation method, a stable indoor environment was maintained, and the COP of the GWHP system increased by 10%. The results showed the potential to further reduce energy consumption and maintain a high level of thermal comfort through the optimization of system operations. Finally, the annual energy consumption was calculated based on the recorded measurements. The results illustrate that this building can reach the ZEB-ready level in Japan. The primary energy consumption can be decreased by approximately 67% compared to the reference by applying the combined system.