Possibility of coupling outdoor air cooling and radiant floor cooling under hot and humid climate conditions

Existing radiant floor cooling systems introduce minimum outdoor air to provide ventilation and to prevent condensation on the floor surface. Conventional radiant floor cooling systems save energy relative to conventional air conditioning systems; these savings arise from the use of higher set-point temperatures and the minimization of outdoor air. In this work, the possibility was analyzed of coupling outdoor air cooling with radiant floor cooling in a hot and humid climate. A radiant floor cooling system using a dehumidified ventilation system with an outdoor air cooling mode was analyzed by a simulation method. Moreover, the behavior of the indoor thermal environment, the system's operation and its energy consumption were reviewed. Simulation modeling to analyze the possibility of using the coupled system was validated against experimental results. Simulations showed that the proposed system can provide cooling energy savings of more than 20% compared to the existing radiant floor cooling system in the hot and humid climate of Seoul, Korea; these savings arise primarily from a reduced operation rate of the radiant floor cooling loop and from reduced energy consumption by the chiller realized through proper operation of the outdoor air cooling strategy. The outdoor air cooling reduced the chiller's electricity use by about 24%. Two outdoor air cooling modes were tested: a temperature-based outdoor air cooling mode was more energy-efficient than an enthalpy-based mode even during the hot and humid season in Korea.