NATIONWIDE MAPPING OF OPTIMUM WALL INSULATION THICKNESSES: A STOCHASTIC APPROACH

Abstract

Energy consumption in buildings accounts for a notable part of the primary energy consumption all over the world. The building industry also has a great potential to decrease the environmental impact by reducing greenhouse gas emissions. The national strategies of many developing countries are shaped by energy conservation issues. Improving energy efficiency and productivity is stated as one of the main elements of the Turkish national energy strategy. An efficient way to decrease energy consumption in buildings is to implement insulation on the building envelope. Identifying the optimum insulation thickness to be applied on the exterior walls is of prime importance. This study adapts a stochastic approach to determine optimum insulation thickness for 81 cities in Turkey. The stochastic approach, unlike the commonly used deterministic approach, incorporates the probabilistic nature of the process and presents the optimum insulation thickness as a probability distribution graph rather than a single value. For this purpose, a number of insulation thicknesses (1-20 cm) were regarded as the alternatives and the optimum alternative was determined based on life cycle costing analysis involving the cost of insulation application and annual energy savings. The average monthly temperature of each city and financial parameters such as the inflation and discount rates were considered as the stochastic elements. The results of the life cycle costing analysis were used to (i) identify the optimum thicknesses in each city as a probability distribution graph and (ii) generate an optimum insulation thickness map for Turkey.