Radiant panel and air heating performance in large industrial buildings

This study determined the vertical temperature gradient in two large industrial buildings with room height close to 10 m. One of the buildings was an assembly hall with air heating system and the other was a warehouse equipped with radiant heating (primary) and air heating (secondary) system. The objective of the study was to determine the differences of vertical temperature gradient in halls during the winter. The findings from this study were used in dynamic whole-year simulations for estimating the heating and ventilation energy differences. The results showed about 0.2 K/m vertical temperature gradients in both halls, which was smaller by a factor of 5 for air heating than guidebook. This difference was likely because of the building being ventilated and well insulated. Temperature gradients kept reasonably constant at all measured outdoor temperatures. Energy simulations with measured gradient values of 0.2 K/m and with outdoor airflow rate during occupied hours 1.0 L/(s·m²), which was enough for ventilation and for air heating with simulated good insulation level, resulted in 15% to 41% higher primary energy for air heating. If it is possible to lower outdoor airflow rates to 0.5 L/(s·m²) during occupied hours, which was enough to remove pollutants from occupancy, the analyzed cases showed 23% lower primary energy for radiant heating.