Investigation of the effect of solar radiation on the optimum insulation thickness

Energy conservation is one of the most important issues nowadays due to the appalling deterioration of the environment as a result of power generation. In this context, researchers are working to save energy in the residential and commercial sectors which consume most energy especially in cold and hot regions. This study, clearly showed the influence of latitude, altitude and surrounding environment conditions on energy requirements for cooling and heating purposes. Therefore the effect of solar radiation has emerged as a very influential factor in buildings design and optimum insulation thickness which achieves energy saving. The study was carried out for Istanbul and Khartoum, which have two different climatic conditions with degree-day method and insulation material polyurethane. In Istanbul without solar radiation effect; annual optimum insulation thickness, energy savings per m2 and payback period were found 0,054 m, 30,3 USD ve 15 years respectively. While in Khartoum 0,107 m, 143 USD ve 4 years respectively too. However with solar radiation effect; In Istanbul this parameters vary between 0,051 – 0,056 m, 27,6 – 33,7 USD, 13,6 - 16,4 years respectively depending to wall direction. While in Khartoum between 0,112 – 0,125 m, 157 - 196 USD, 5,4 – 6,3 years respectively depending to wall direction too.