Effect of spot air movement on thermal comfort and energy saving in an airconditioned space

Abstract

The paper presents the effect of spot air movement on human thermal comfort and energysaving and proposes the technique of using a small fan combined with an air-conditioner to increaseroom air temperature set point. The technique was created from the idea that Thai people have atolerance to high air temperature and are alsoo accustomed to high air movement from electric fans innon-air conditioned space. This method should be used in all air-conditioned space in Thailand tosave energy. In the study, 15 students in total were tested in a room equipped with a 12,000 BTU/hrsplit-type air-conditioner. Room air temperature was varied from 25, 26, 27 and 28 oC every one hour.A small fan with 6-inch diameter was placed in front of each subject. In each hour, the speed of thefan was varied to supply a spot air velocity from 0.2, 0.5, 1, 1.5 and 2 m/s. During each condition, thesubjects were asked to vote for their thermal sensation. The results showed that the temperature setpoint could increase to 28 oC and when a small fan was used to supply spot air velocity from 0.5-2m/s. This would reduce the electricity consumption of the air-conditioning unit by about 18%.