Towards promoting sustainable construction in Egypt: a life-cycle cost approach

Abstract

People spend most of their life in buildings, be it homes, work places, education facilities or entertainment centers. Buildings as such represent a large economical investment and have significant impacts on our lives and performance. With the presence of challenges such as the rise in greenhouse gases emissions, global warming, resource depletionâ ¦..etc., buildings' designers should have future visions and innovative solutions. Designing sustainable/green buildings will be an indispensible alternative in the construction industry. However, investors in developing economies might overlook all considerations except their profit. Thus, this research aims at promoting green construction in Egypt by showing the savings and economic benefits that investors could harvest. Ideally, green building design should have aims to meet a customized design for each building based on its location, surrounding weather conditions, required performance, environmental contribution and owner's preferences. This research introduces a framework for green buildings design to support planners in choosing optimum customized building envelope designs (orientation, walls, windows and roof) with the least possible costs over the building lifetime. The proposed framework uniquely focused on using sustainable approaches (material efficiency, indoor quality, energy efficiency, passive solar design and natural illumination) to meet least life-cycle costs. Moreover, it introduces four modules to reach this goal: (1) interactive database to include system setup information and owners preferences; (2) systems builder to form different systems components; (3) systems assessment that includes thermal, energy demand, daylighting and cost assessments of built systems; and(4) optimization engine to link the three modules and reach all requirements with least life-cycle costs. A friendly prototype(Easy Design Integrated Tool- EDIT)is introduced based on the proposed framework. It represents a comprehensive and easy application tool that advises the optimum design for each facade wall, window, roof and building orientation. A medium size residential building case study was implemented using the (EDIT) model. The (EDIT) output advises orienting the building towards the North with the use of high thermal insulation (rice straw blanket) for the building envelope walls and roof. A comparative analysis of this case study is introduced between the green design results and alternate design of least initial costs. Although the (EDIT) green design shows an increase in initial investments of 5.4%, the life-cycle costs produces savings reaching 16.3%, and energy savings of 49% annually. The compounded payback period is computed to be about 3 years. Simulation of all possible design systems combinations is conducted to provide a global view on possible compromise between buildings design life-cycle costs, energy costs and initial investments. Finally, surveys are developed concerning the (EDIT) model to score its performance in terms of its capabilities, ease of use, quality of output and overall satisfaction. The surveys were distributed to design consultants and investors with 5-15 years of experience in the Egyptian construction field market. The surveys output shows high scores regarding the (EDIT) model overall performance and proves that it can aid consultants, project managers and owner organizations to reach optimum building envelope systems design that ensure sustainability approaches and operation with least possible costs.