A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Environment Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1999

Knowledge and understanding of heat transfer through a roof to an air-conditioned building have become a necessity for providing comfort of human being as well as for rational use of energy. The mechanism of heat transfer is a dynamic phenomenon influenced by many factors such as instantaneous solar radiation, thermal properties of materials, ambient and interior temperature. The objective of the experiments was to study the Thermal performance of a kind of reflectible surface-TYVEK in reducing the heat transfer. TYVEK was installed as ceiling with different configurations, and it was used to compared with other ceiling materials-cellocrate and acoustic board, results from measurement presented a significant reduction in heat flux through ceiling of TYVEK as ceiling than other ceiling materials. TYVEK installed as flat ceiling with forced ventilation was proved to be the best configuration in case of slope roof type, and TYVEK installed as flat ceiling in case of flat roof type was proved to be the best confoguration. This thesis also studied the shading effect of a three dimension object such as a tree ( the tree is assumed to be a ellispsoidal object by its shape), method has been developed to calculate the shaded area cast by a tree on an arbitrary plane at any given time, Experiments were conducted to evaluate the shading effect in reducing heat transfer through ceiling with flat roof when there was a shade on it. A computer model simulating heat transfer mechanism in the attic was used to calculate heat flux and temperature, finite difference method was used in that model to consider the transient heat transfer situation, good agreement was found between measurement and simulation which proved the validity of the model.