Center for the Built Environment
Enabling energy-efficient approaches to thermal comfort using room air motion
- Author(s): Pasut, Wilmur
- Arens, Edward
- Zhang, Hui
- Zhai, Yongchao
- et al.
In warm environments, room fans can provide comfort using substantially less energy than air- conditioning. The savings are greater if the fans make it possible to successfully condition the building with natural ventilation or evaporative cooling systems, instead of chillers. Although there are many laboratory studies of comfort using desk fans and personalized fans, tests for ceiling fans are rare, mainly in early studies from the 1980s. This study examines the cooling effect of a low-wattage ceiling fan on occupants when air comes from different directions with different speeds. We conducted 96 human subject tests in an environmental chamber. Sixteen college students each experienced 6 air movement conditions: two different air speeds and three different air directions between fan and subject: from front, side, or right above the head (total eleven configurations). The difference in thermal comfort and thermal sensation generated by fixed and oscillating fans was also investigated. The temperature and humidity conditions for the tests were 28 °C and 50% RH.
It was found that the majority of subject (70%) perceive the thermal environment without fans comfortable. This number rise to 100% for some configuration with fans. Our subject found that the oscillating air movement had no effect in terms of improved thermal comfort or thermal sensation, but it greatly improves their air quality perception. The subjects did not report any dry eyes discomfort for any of the eleven configurations.