A combined method of experimental and numerical simulation was used in this paper to study the surface temperature variations of radiant panel in the start-up stage of radiant ceiling system

and the condensation characteristics of radiant panels were analyzed under different moisture strengths and locations of human being in the stable stage of radiant ceiling system. The results show that in the start-up stage when the radiant cooling system is operated independently

the condensation occurs on the radiant panel after the system starts 6 minutes

and the decreasing of radiant panel surface temperature has more significant impact on the condensation time than the increasing of moisture strength. So it is necessary to take effective measures to prevent condensation in time in the start-up stage. In the stable stage

the radiant panel condenses about 12 minutes earlier when the moisture strength equivalent to an adult man body is additionally added. And the radiant panel which is exactly above the moisture source condenses earlier than others. So the surface temperatures of radiant panels above the moisture source should be monitored to prevent condensation.