Experimental evaluation of the impact of real sun patch on radiant floor heating in highly glazed spaces

When the floor heating system is integrated into highly glazed buildings, the uneven distribution of temperature and humidity caused by the long exposure to the direct solar radiation becomes more and more prominent, which affects the indoor thermal comfort. Given that this issue has already been studied by means of mainly numerical simulations in previous studies and that thermal comfort already needs to be considered by means of a questionnaire, leaving a large room for improvement in terms of experimental considerations. This study quantitatively and qualitatively analyses the evaluation of the impact of real moving sun patch on radiant floor heating for thermal comfort consideration. The effects of long exposure to sun patch on both thermal comfort and thermal sensation are objectively assessed by means of experimental measurements conducted on a thermal manikin placed in a controlled and monitored test cell exposed to non-controlled climatic conditions. The results show that the indoor air temperature exceeds 26 °C, even in winter season, when the sun patch appears and is exaggerated when its duration is extended. The decrease of floor surface temperature is positively correlated with the decrease of sun patch area. Extending the sun patch duration allows the heat absorbed by the floor increase the outlet water temperature and, thus, impact the thermal sensation and thermal comfort. Based on this, future contributions may be to eliminate overheating by combining ventilation systems, intelligent control systems, as well as to recover the radiant heat generated by the sun patch. •Actual sun patches on radiating floors were experimentally studied, avoiding heating films or simulations.•Objective evaluation utilized a Thermal Manikin Newton® instead of subjective volunteer surveys.•Sun patches in radiation heat systems cause discomfort to occupants.•Exposure to sun patch reduces thermal comfort due to floor heating system's thermal inertia.