Management of Thermal Comfort in Smart Homes: Assessing Radiator Performance under Controlled Seasonal Ventilation and Humidity Conditions

Abstract

This study evaluates the thermal comfort performance of a conventional hydronic radiator system in a smart home under varying seasonal, ventilation and humidity conditions. A validated Computational Fluid Dynamics (CFD) model, supported by sensor-based measurements, was used to simulate twelve scenarios: six summer cases with an outdoor temperature of 20 °C and six winter cases with an outdoor temperature of 5 °C, each with open- and closed-window conditions and relative humidity levels of 30%, 50% and 70%. Thermal comfort was assessed using the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indices. The results show that the radiator system maintained slightly warm but near-acceptable comfort in summer closed-window cases, but failed to achieve acceptable comfort in winter, even with windows closed. Open-window conditions caused substantial comfort deterioration through ventilation-driven heat loss, with the winter open-window cases producing severe cold discomfort (PMV < -2.18, PPD > 82%). Regression analysis showed that air temperature was the dominant predictor of comfort, while relative humidity had only a weak linear influence within the tested range. Spatial analysis revealed clear thermal non-uniformity, particularly in transition zones, with localised overheating observed in the stair/landing area. Overall, the findings indicate that effective smart radiator control in modern dwellings should prioritise window-state awareness and zonal control, while treating humidity as a secondary comfort variable.