Calculation of energy efficiency according to optimum cost analysis in historical buildings: İzmir case

The importance of the concept of energy efficiency has increased in recent years and has taken its place in the development goals of the countries. The fact that buildings have a high share in total energy consumption makes it necessary to improve energy performance both in environmental and economic terms. The Energy Performance of Buildings Directive (EC, 2002), which was published by the European Union in 2002 in order to achieve the objectives of increasing energy performance in buildings, contains legal limitations and calculation method. Subsequent revisions (EC, 2010, 2018) have introduced the concept of an optimal cost-effective energy level and published guidelines for the implementation of the methodology (EC, 2012a; 201b). Although the steps to increase energy efficiency in buildings have focused primarily on new buildings, existing buildings have always maintained their importance. As it is known, it is important that historical buildings are included in the existing building stock in order to increase energy efficiency and improvement works in order to achieve carbon neutral building targets. In this thesis, energy efficient improvement measures taken in a historical building located in hot-humid climate zone are aimed to determine optimum cost energy level in energy retrofitting works. Energy consumption values and global cost calculations of scenarios created by energy efficient measures determined in the historical building example where the field study was conducted were compared with each other. In the study, calculation periods are taken as 10, 20 and 30 years and the effect of the changes in the discount rate on the results is also evaluated. In determining the optimum cost energy level, the calculations were carried out in accordance with the regulation published by the EU council. Electricity cost, inflation rate and bank interest rate determined based on statistical data, and as a result of calculations made for a 30-year calculation period, energy efficient measures taken in building envelope (heating insulation, windows), lighting and mechanical systems and photovoltaic (PV) panel application resulted in optimum cost-effective energy level was obtained. The most efficient measures in terms of energy and cost effectiveness were identified as improvements to the lighting system and the application of PV panels. However, the lowest level of efficiency was found in the application of thermal insulation to the roof of the roof and basement. The insulation thicknesses of the wall vary between 3 cm and 6 cm and 6 cm insulation thickness gives the best result in terms of energy efficiency, but in terms of cost effectiveness, 5 cm insulation thickness has reached the optimum result. The measures taken in the windows are more efficient in terms of cost and energy efficiency than the thermal insulation measures and the addition of a secondary joinery internally gave more effective results than the use of glasses with low solar heat gain coefficients. The effects of investment costs on optimum cost energy level calculations were determined by sensitivity analysis performed at calculation period, discount rate and energy price increase rate. The shorter the calculation period, the less the impact of global costs and energy gains on global costs. Sensitivity analysis of discount rate has shown that the increase in discount rate has a decreasing effect on global costs. Decreasing energy price increase rate also shows a decreasing effect on global costs. Changes in economic parameters that lead to a reduction in annual costs reduce the cost effectiveness of scenarios with high initial investment costs.