Numerical Study of the Effects of Speed and Place of Ceiling Fans on Thermal Comfort and Reducing Energy in Office Buildings

The main aim of the present study is to investigate the effects of speed and place of ceiling fans on thermal comfort parameters (predicted mean vote and predicted percentage of dissatisfied) and energy expenses in two different office rooms with a certain geometry in winter using district heating system. In all of the models, the regime of a flow is turbulent and governing equations are solved by finite volume method and SIMPLE algorithm. Based on the results, using ceiling fans in winter (heating system) has a considerable influence on the improvement of buildings thermal comfort and reducing consumption of energy. By using ceiling fans the effective temperature of room increases and therefore radiator energy consumption decreases. Furthermore, the results show that the location of ceiling fan does not have any effect on room effective temperature and residents’ thermal comfort. According to the results, predicted mean vote and predicted percentage of dissatisfied parameters improve by turning ceiling fans on and increasing fan normal air velocity. But, the operation of fan leads to cooling system after a certain velocity and it is not acceptable for the heating system. Finally, the CF.A case with p(x)=1.0 m, V=0.2 m/s and Tradiator=51oC, and CF.B.1 case with p(x)=2.5 m, V=0.27 m/s and Tradiator=37oC, by providing thermal comfort conditions and reducing consumption of energy about 58% and 73%, respectively are reported as optimal cases.