Life-cycle assessment and cost analysis of residential buildings in South East of Turkey: part 2-a case study

Residential buildings play an important role in consumption of energy resources. About 40 % of all primary energy is used in buildings all over the world. This paper is the second part of the study on the life-cycle energy (LCEA), emissions (LCCO(2)A) and cost (LCCA) assessment of two residential buildings constructed in urban and rural areas. In the first part, the methodology, formulations and procedure for such a comprehensive analysis are provided, while this paper provides an application of the methodology that considers two actual buildings located in Gaziantep, Turkey. The proposed model focused on building construction, operation and demolition phases to estimate energy use, carbon emissions and costs per square meter over a 50-year lifespan. The optimum thickness of insulation used to reduce energy consumption and emissions per square meter is determined. It is found that the operating phase is dominant in both urban and rural residential buildings and contributes 87-85 % of the primary energy requirements and 88-82 % of CO2 emissions, respectively. Life-cycle greenhouse gas emissions were 5.8 and 3.9 tons CO2 eqv. for BT1 and BT2, respectively. It is calculated that the life-cycle energy consumption and CO2 emissions of the residential buildings can be reduced by up to 22.8 and 23.4 %, respectively, by using a proper insulation material for the external walls. The life-cycle cost, consisting of mortgage, energy, maintenance, service and demolition payments are calculated to be 7.28 and 1.72 million USD for BT1 and BT2, respectively. Building envelope developments, such as better wall insulation, provide noteworthy potential energy savings and contribute to the reductions from cooling and space heating. Therefore, primary strategies and technologies needed for efficient buildings include optimal insulation of external walls. The economic insulation thickness of the residential buildings in Gaziantep is determined to be 80 mm by using a life-cycle cost analysis. The results show that because of the differences in building structures and living standards, life-cycle energy intensity and CO2 emissions in urban residential buildings are 29 and 25 % higher than in rural conditions.