Optimal thermal comfort quantification in domestic indoor spaces under varying ambient and seasonal conditions – a numerical approach

One of the most crucial factors to consider in an indoor space is the ability to provide a comfortable and safe environment for its occupants. The right combination of relative humidity, temperature and ventilation is important not only for comfort but also for preventing the spread of respiratory diseases. In countries where there is wide ambient condition variation between seasons, it is not always straightforward to decide the right balance between heating/humidity settings and sufficient ventilation for a safe indoor environment. This study employs Computational Fluid Dynamics to assess the interaction between these parameters and determine the optimal radiator surface temperature for thermal comfort. Two seasons were considered (winter and summer) with three relative humidities and radiator surface temperatures. While relative humidity influences thermal comfort, the study reveals how it interacts with ventilation and heating under varying seasonal conditions. The effect of radiator surface temperature on thermal comfort was also examined, with five temperatures studied. Results show that an acceptable range of thermal comfort was achieved when the indoor space is heated with a radiator surface temperature of 49–53°C. Indoor spaces will be thermally uncomfortable with radiator surface temperatures below 43°C under all conditions.