Performance of the Outdoor Evaporative Cooling: A Case Study of Thammasat University Rangsit Campus

摘要

It is very important to maintain the thermal comfort for the residents at outdoor arena, to develop sustainable cities and promote outdoor activities for the residents. Although, there are many passive ways to maintain that thermal comfort at outdoor spaces without using much energy like the design and orientation of the building envelope. Also, adopting passive measures like using shades, and shading of trees, reflectors, shutters, louvers and so forth, help in mitigating the heat in a building. Similarly, humans can adapt to the environment by making changes in their physiological behavior to help combat extreme weathers too, like maintaining healthy habits, diet, posture, use of light clothing and so on, and adapting to the environment. However, in humid and hot areas like Thailand where the weather challenges the residents to extreme, there are ways to maintain the thermal comfort using little energy for the outdoor spaces. Evaporative cooling is one of these options. This study was conducted to analyse the effectiveness of direct evaporative in an open area at Thammasat university, Rangsit campus. We collected the data by installing sensors at the evaporative coolers to analyse how much energy it requires to operate, and its performance and effectiveness by measuring the outdoor temperature and humidity with and without the use of evaporative coolers. The data was recorded from October 31 to November 1, 2019 on hourly basis. This data was tallied with the environmental meteorological data which was measured at Don Mueang international airport station. The type of the evaporative cooling systems installed at the Thammasat university is the jet fan type direct evaporative cooling system (DES) system. It is important to check the effectiveness of evaporative coolers by calculating air enthalpy at different times of the day. This way, we tried to see at what time of the day, at what temperature and at what enthalpy the evaporative coolers are most effective. Moreover, we found out what should be the effective daily duration of evaporative coolers operation. We also calculated the energy offset, that is, the total energy saved using evaporative coolers which could not have been saved, if air conditioners had been used instead.