Annotated Summary

Wong, N.H., & Chong, A. (2010). Performance evaluation of misting fans in hot and humid climate. Elsevier Ltd – Building and Environment, 45(12), 2666-2678. Retrieved from https://www.researchgate.net/publication/222826861_Performance_evaluation_of_misting_fans_in_hot_and_humid_climate

This article is a study conducted by Wong & Chong (2010) to examine the effectiveness of misting fans in a hot and humid climate. The authors sought to evaluate the change in thermal comfort level with the use of misting fans as well as estimate the potential rise in biological pollutants brought about by the higher humidity due to the mists generated. To do so, field measurements at two similarly orientated food centres as well as an experiment within National University of Singapore (NUS) were conducted to determine the thermal conditions and thermal sensations created by the misting fans. Results showed that misting fans were largely more successful in lowering ambient temperature as compared to the non-misting fans, but the relative humidity recorded under the misting fans were consistently higher. Based on thermal comfort and thermal sensation voting outcomes, the lower ambient temperature seemed to have a greater effect on thermal comfort levels compared to the higher relative humidity. The effect of evaporative cooling from the mist generating system was also found to be enhanced at higher air velocity. From the use of collection of biological samples from the 2 food centres, it was found that the higher relative humidity provided a more conducive environment for bacterial and fungal growth. To tackle the increased growth of biological pollutants, the authors thus suggested a possible alternative called the two-stage indirect/direct evaporative cooling system. However, they also stated that there is a need for further studies conducted on the feasibility of such a system in a semi-outdoor area. Moreover, to enhance comfort levels as well as to address the problem of biological pollutants, there is also a need for studies to be conducted on the incorporation of a dehumidifier unit to further reduce air humidity levels.