The role of the front pattern shape in modelling personalized airflow and its capacity to affect human thermal comfort

The aim of the tests was to demonstrate the influence of the front pattern shape and its effect on human thermal sensations. Both the cooling capacity in summer conditions and the heating capacity in winter conditions were considered. Eight different types of the front pattern were tested at constant working parameters such as airflow (20 l/s), temperature of supply air (24 °C - summer conditions, 22 °C - winter conditions) and ambient temperature (28 °C - summer conditions, 18 °C - winter conditions). In order to determine the thermal sensation, a thermal manikin was used and equivalent temperature value teq was applied. On the basis of test results, differences in airflow characteristics were demonstrated and its varied influence on thermal sensation. The patterns with round apertures had greater cooling capacity as compared to the other shapes(cross-, rectangle- or star-shaped apertures). Among the round apertures, better values were achieved by those with higher diameters. The most advantageous patterns tested were those with round apertures of 15 mm diameter and 30-50% perforation ratio. These allowed for high cooling effect in summer conditions and considerable teq increase in winter conditions, as compared to that without PV. Operating PV brought about changes in the results teq at the level of 25-30% in summer and 60-75% in winter, as compared to the values obtained without PV, which additionally justifies the rationale behind application of PV.