Optimum Design of Air-Conditioned Buildings

The main consideration in the design of thermally insulated buildings, apart from the energy required for operation, is the total (initial plus operating) cost. There is no simple explicit relation between the total cost and energy required to maintain the desired inside conditions which are dependent on the uncontrollable outside conditions. With limited energy resources, it is necessary to conserve energy or use it optimally. A unified approach to find the optimal combination of initial cost and operating cost (energy) or total energy requirements (cooling plus heating) for air-conditioned buildings is presented in this paper. Since the thickness of insulation is one of the important factors to be considered in reducing the external load, the optimum values of insulation thickness for walls and roof are found by using the interior penalty function method of minimization. For the computation of heat gain through external walls and roof, a design day based on the average maximum solar-air temperature (computed from the hourly meteorological data) is chosen. The sensitivity of optimum design with respect to design parameters is also found.