A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering.

Thesis (M.Eng.) - Asian Institute of Technology, 2003

Nowadays, Energy conservation of commercial building is well-known but there are some problems in evaluate energy saving from improving measure suggested by energy consultants. Before giving advice to these building owners who will make decision to invest money to the energy conservation project, we need to have some method, which accurate in measuring the energy consumption of building. OTTV formulation is done first because it is a heat gain through building envelops transferring to load of air-conditioning system, which is the largest part of energy use in commercial building. The regression method is used for evaluating constant values of the equation which are equivalent temperature difference of opaque wall, average temperature difference between indoor and outdoor and Solar Factor. Then, Energy equation is evaluated by regressing coefficients of internal loads generating to air-conditioning system so cooling load of air-condition system can be calculated. After that, summation of energy use by air-condition system with energy use by lighting system, equipments and other systems is formulated to energy equation. The DOE2 simulation program is used to calculate cooling load of generic building at different parameters. The generic building is an office building, which is the most common type of commercial buildings. The results from DOE2 program will be compared with another simulation program, which is EP Program. Energy equation is used to calculate energy use of existing building and compared results with audit report data.