The application air-plant green roof for residential building in hot-humid climate

Abstract

The idea of green roof can be developed into a design guideline. It composes of natural methods that benefit to the surrounded environment. According to the experiment, green roofs can reduce thermal storage space during daytime. Moreover, it can also reflect heat at night. With that reason, green roofs can reduce solar heat transmission of buildings as well as energy, which leads to sustainable solutions toward global warming. This research aims at studying green roofs energy efficiency by growing air plants on residential building in tropical climate area. The experiment was conducted in Songkhla, situated in the South Thailand at latitude 60° 55N and longitude 100° 26E, during April to November. There were two main types of air plants used in the study, Spanish moss and Tillandsia Cotton Candy. Both of them are monocotyledon plants in family of Bromeliaceae and Genus of Tillandsia. Air plants are easy to maintain and can tolerate to various weather conditions. In addition, it also has lower weight and does not need soil too. The leaf surface has tri-chrome cover as to help vapor gas and other substances trap. This research has set up three different mocked up rooms for the temperature test. The temperature performance study decreased according to density and air gap of air plant. The temperature comparison of two air plants and fiber cement roofs was measured in both day and night time. The result from the temperature performance study has decreased depending on the density of air plants. The main factors which influencing the decrease in temperature were leaf area density. According to the study, the result from temperature performance study revealed that the density of air plant decreased the day time (1,500 g/0.144 m3). Moreover, Spanish moss can reduce temperature more than Tillandsia Cotton Candy. The temperature can be reduced up to 8.1 to 6.87 degree respectively. During the night time, Tillandsia Cotton Candy at density of 1,500g/0.144m3 can reduce the temperature more than Spanish moss at density of 500g/0.144m3. The temperature can be reduced up to 4.20 and 3.43 degrees respectively. The result from temperature performance shows that the decreased temperature on the 30 cm air gap during the day time at density of 1,500g/0.144m3 of Spanish moss was more than Tillandsia Cotton Candy. It can reduce the temperature up to 8.1 and 6.87 degree respectively. During the night time, Tillandsia Cotton Candy can decrease roof temperature more than Spanish moss in 40 cm air gap and density of 1,500g/0.144 m3. The decreased temperature are up to 4.20 and 4.10 degrees, respectively. The research can be concluded that air plant species, density and air gap all affect the decreasing temperature of the surface and ambient in residential buildings. Green roof at the density of 1,500g/0.144m3 can reduce the highest temperature during day and night time. The 30 cm air gap and density of 1,500g/0.144 m3 air plants can decrease the temperature at its highest during night time. The 40 cm air gap and density of 1,500g/0.144 m3 green roof can reduce the highest temperature.