A model proposal to obtaining energy and cost efficient alternatives from life cycle perspective for residential buildings in Turkey

Technological developments increase human's dependency to energy. Therefore, it has critical role in country's economic growth and development. But energy become an important issue in world's agenda due to lack of non-renewable energy sources in near future and environmental pollution which is produced from non-renewable energy source consumption. As it is known building sector is responsible from significant portion of energy consumption and greenhouse gas emission. Therefore, energy efficiency in buildings have important role for country's economic growth and development. Tukey's energy supply has increased in years and domestic energy production meet only 25% of demand and rest of the demand has supplied from abroad. Security of energy supply source and economic dimension of energy imports affect turkey's economic growth negatively. Thus, energy consumption became an important issue due to reasons which is point out above. Countries have determined own targets and strategies on energy efficiency with the studies. Energy Performance Directive for Buildings (EPBD) (2002 and recast 2010) which is developed by European Union Assembly, Kyoto Protocol (2009) and United Nations Framework Convention on Climate Change (UNFCC) (2004) are some important international studies for energy efficiency and greenhouse gas emission reduction. Although energy efficiency in buildings is important issue, studies which is done in Turkey aren't sufficient for Turkey's targets on energy efficiency. According to literature survey there are remarkable studies on energy efficiency in buildings which consider energy consumption from life cycle perspective. Buildings' life cycle includes different phases as, raw material extraction, transportation of building materials to construction site, constructing building, operation of building, maintenance of building and demolition of building. As it is known, buildings consume energy and cause greenhouse gas emission during their entire life cycle. But standards or directives on energy efficiency such as EPBD doesn't consider energy performance from life cycle perspective. Therefore this study focus on energy performance evaluation from life cycle perspective. Considering annual energy performance of buildings instead of life cycle energy performance prevent net energy consumption performance and energy saving potential. Life cycle energy analysis have done without detailed data or include limited phase of life cyle in previous studies. But phases which has remarkable effect on life cycle performance includes analysis in the study. Environmental performance such as greenhouse gas emission and cost performance doesn't consider with energy performance from life cycle perspective in standards and directives. Therefore in thesis study, a model proposal has been developed for obtaining design alternatives which have optimum energy, environmental and cost performance during life cycle for buildings. Model could be applied all building typology. But it is limited with residential buildings in the study due to large number of residential building which should be renovated or new design. Model has developed for new buildings. But it could also applied energy efficient retrofitting of existing buildings. However, model work flow should be revised while applied existing buildings. The model is limited with energy consumption, greenhouse gas emision and cost criterias but different criterias could be added according to the aim and scope of study. The main aims of the model as follows; • Developing a model obtaining design alternatives which have optimum energy, environmental and cost performance during life cycle for residential buildings in Turkey. • Getting new ideas or evaluating existing ideas on energy efficient building design after application of model to the residential building for different climate regions. Thus, building design ideas, which has optimum energy, environmental and cost performance during life cycle, could obtain for different climate regions of Turkey. Model is formed of six main steps and substeps. It has applied to the multi-storey residential building which is developed by Turkish Housing Development Administration (TOKI). The residential building, which is model applied, assume that construct in three different climate region of Turkey warm-humid (İzmir), cold (Erzurum) and temperate (İstanbul). Design alternatives evaluated from energy consumption, greenhouse gas emission and cost during building's life cycle. As it is known, life cycle analysis need large amount of data and assumptions. But there is a problem for getting some data such as embodied energy of building materials in Turkey due to lack of necessary data. Data, which is not obtaining from national database or standards for life cycle performance calculations, are gathering from international database. Assumptions about occupancy, household equipments and lighting system for energy performance calculations in operational period of the building are gathered from national research project which is based on statistical data about residential buildings. According to findings, energy, greenhouse gas emission and cost performance analysis from life cycle perspective is necessity for energy saving and greenhouse gas emission reduction targets. Design alternatives for building envelope should be determined according to multi criteria such as energy, greenhouse gas emission and cost from life cycle view. Performance of design alternatives are significantly different according to selected criteria, building typology and climate regions. Energy efficient design strategies such as increasing thermal insulation thickness perform as expected from point of energy saving and greenhouse gas emission reduction. But same strategy decrease energy consumption while decreasing greenhouse gas emission in warm climates. Consequently, standards and directives on energy efficiency should be revised with life cycle approach according to building typology and climate. According to findings there is remarkable energy saving greenhouse gas emission reduction and cost reduction with obtaining design alternatives which has optimum life cycle performance.