การศึกษาเพื่อหาแนวทางในการสร้างต้นแบบระบบหลังคาเพื่อลดการถ่ายเทความร้อนเข้าสู่อาคารในเขตร้อนชื้น / พรหมสิทธิ์ สร้อยระย้า = A study to develop a prototype of tropical roof system to reduce heat gain / Promsit Sroyraya
Heat is an important factor that affects the resident in tropical climates. The roof is a part of the building that obtains the maximum heat and that causes the increase in the air-conditioning. The objective of this research is to analyze and search for the model roof that can be developed to stop heat gain in the tropical climates by studying the variables that effect heat gain and apply it for the model roof creation. To control the variables a experimental building was created which is 4.40 m wide, 7.90m long and 2.85 m high. The wall were made of polystyrene insulation and 4 of the houses are equipped with the roof's model which are 0.90 m wide and 0.90 m long. This experiment is carried out in an air-conditioned place. The data was recorded in every 15 minutes for 48 hours. The research has been divided into 2 parts. The first part deals with the variables and then compares the result of the heat transfer into the roof with different angles: 15 degrees, 30 degrees, 45 degrees and 60 degrees. The results of this experiment showed that during the daytime, the least heat gain into building was the roof with 60 degrees at 19.15 Btu/hr. The second part was to compare the effectiveness of the roof system in term of reducing the heat gain. The experiment was divided into 3 sets. The first set was comparing the different roof system and found that heat enters the roof insulated horizontally the least which account at 28.92 Btu/hr if comparing with metal sheet roof without installation. The second set was comparing the heat loss and heat gain in the roof system by color indicators which are white, green, and black. The roof with black sheet material has the highest heat gain. The third set was a comparison between the roof insulated with 3-inch-thick insulation and 6-inch-thick and found that 6-inch-thick insulation had the least heat transfer. It can be concluded that the heat from the sun is the strongest factor that effects the heat transferring into the building. Generally the roof at 60 degrees is better at preventing heat gain when compared with the 15 degree roof. The heat transferring under the cavity of the black roof can reduce the heat loss at a 18.38% rate and in use together with 6-inch-thick horizontal insulation would be able to reduce the heat gain 90.28% compared to the metalsheet roof without insulation
