Theoretical and experimental investigation of cooling load temperature difference (cltd) values for building walls and flat roofs

In this thesis, Cooling Load Temperature Difference (CLTD) values for the commonly used multilayer building walls and flat roofs are obtained by using theoretical and experimental methods. A new periodic solution technique is applied for solving transient heat transfer problem for the building walls and flat roofs. The technique known as Complex Finite Fourier Transform (CFFT) technique is the first time used to obtain CLTD values for the building walls and flat roofs. Therefore, experimental system consisting of two testing rooms with eight types walls and two different roofs are used in the University of Gaziantep Campus to compare CLTD values for these elements. In the experimental study, inside and outside air temperatures, surface temperature of each layer of the walls and roofs and solar radiation flux on horizontal surface are measured instantaneously. Heat gains and CLTD values for the walls and roofs which are calculated using measurement values, and compared with theoretical results. Also, economic analysis has been done for some walls and roofs for finding the best wall type and optimum insulation thickness. A computational procedure based on the periodic solution is developed, and a program in Matlab is prepared for the numerical calculations. Validation for that model has been done by comparing CLTD values for some selected walls and roofs given in ASHRAE handbooks. It is observed that there is a considerable agreement between computed CLTD values and provided in ASHRAE handbooks for the selected structures. The results of economic analysis for ten years show the Roof 1 and AAC wall are the best for Turkey, as well as Roof B and Wall E the best for Iraq. Optimum thickness for Roof1, AAC wall, Roof B and Wall E are 36.7, 10.1, 24.5 and 10.8 cm, respectively. Keywords: Cooling Load Temperature Difference, solar radiation, heat gain, cooling load, economical analysis.