A heat and moisture transfer model of an experimental room under the combined cooling mode of radiant panel cooling and a fan coil unit was established in this study. It was proposed to consider the radiant panel as a special “cooler”. The radiant panel was divided into a dry condition and wet working condition when processing indoor air. Under the dry condition

the radiant panel treated the air in a constant vapor content. Under the wet condition

the radiant panel treated the air withan enthalpy reduction and a dehumidification. During the summer

experimental measurements were taken on parameters such as the temperature and humidity of the radiant cooling system and state points were expressed on apsychrometric chart. The load of the fan coil unit and the radiant panel were calculated. The results show that when the water temperature of the radiant panel is 20 ℃

the radiant panel only bears the sensible heat load at a size of 0.85 kW; when the radiant panel water temperature is 10 ℃

the radiant panel operates under wet conditions and the latent heat load is 0.10 kW. Critical state conditions are obtained for controlling the radiant panel without condensation based on the psychrometric chart

i.e.

the state of the convective air from the radiant panel has equal enthalpy of the indoor air state.