Development of a Decision Support Tool for nZEB (nearly Zero Emission Building) at the Early Design Stage

Abstract

Financial problems are one of the major causes for sluggishness in realizing sustainable buildings. There is a pervasive perception among investors that an increase in the initial investment cost for building environmental improvement is financially denting. From the perspective of a building′s life cycle, building environmental improvement and economic effect have an integrated composition. This is because the building operating period is long and this results in huge operating costs. When ″green premium″ (initial investment cost increases with the use of technology necessary for sustainable buildings such as energy saving or CO₂ emissions reduction) is invested, a considerable decrease in operating cost is expected at the operation stage. As the oil price is continuously increasing and a carbon tax is very likely to be imposed, the effect of ″green premium″ is anticipated to a greater extent. In contrast, if there is no information on life cycle cost analysis at the initial design stage when deciding ″green premium″, the investment of stakeholders can hardly be expected. This is considered as the leading cause for failure to realize sustainable buildings throughout the world. In particular in Korea, analysis techniques and experts are considerably insufficient. Therefore, this paper proposes the development of a Decision Support Tool for evaluating the reduction effect of CO₂ emissions against the cost, which is available at the early design stage. For this, a program has been developed with a database after implementing a CO₂ emission evaluation module, life cycle cost evaluation module, and output module for cost-effectiveness.