Experimental study on the thermal comfort in the room equipped with a radiant floor heating system exposed to direct solar radiation

In buildings with highly glazed facades, the main drawback of radiant floors is the overheating problem when exposed to direct solar radiation. Combined with local climate data from Troyes, an experimental investigation was performed under various exposure duration 2, 4, and 6 h with different solar intensity scenarios that were experimentally realized by a heating film. Indoor air temperatures and floor surface temperature were measured. Obtained results showed that the maximum floor surface temperatures all exceeded the limitation of 29 °C during the sunshine durations. When the sun patch was applied on the floor, the building type changed from category A to category B in terms of the vertical air temperature difference. To sum up, the sun patch indeed gave rise to floor overheating problems in the case of the existing control system, and the case of 6h sunshine duration with an intensity of 718 W/m2 would lead to the worst living conditions taking all factors consideration. The findings and insights of this study will provide an experimental database for designers and engineers. •Sun patch is experimentally simulated by a heating film regarding various durations.•An overheating coefficient is proposed to quantify floor surface overheating.•The overheating coefficient is not positively associated with the sun patch duration.•Effects of sun patch on air temperatures are stronger with the sun patch duration.