Evaluating the Use of Displacement Ventilation for Providing Space Heating in Unoccupied Periods Using Laboratory Experiments, Field Tests and Numerical Simulations

Displacement ventilation is a proven method of providing conditioned air to enclosed spaces with the aim to deliver good air quality and thermal comfort while reducing the amount of energy required to operate the system. Until now, the practical applications of displacement ventilation have been exclusive to providing ventilation and cooling to large open spaces with high ceilings. The provision of heating through displacement ventilation has traditionally been discouraged, out of concern that warm air supplied at the floor level would rise straight to the ceiling level without providing heat to the occupied space. Hence, a separate heating system is regularly integrated with the displacement ventilation in cold climates, increasing the cost and energy use of the system. This paper goes beyond the common industry practice and explores the possibility of using displacement ventilation to provide heating without any additional heating system. It reports on experimental investigations conducted in laboratory and field settings, and numerical simulation of these studies, all aimed at investigating the application of displacement ventilation for providing a comfortable indoor environment in winter by preheating the space prior to occupancy. The experimental results confirm that the proposed concept of providing space heating in unoccupied periods without a separate heating system is possible with displacement ventilation.