Life-cycle cost analysis for façade retrofit measures of residential buildings in Cairo

Abstract

Nowadays, energy retrofit for existing buildings has become a worldwide approach to reduce total energy consumption. A wide range of energy-efficient retrofit measures is actively affecting the decision process, of which retrofit alternatives should be used. The existing study aims to evaluate the effects of façade retrofit measures in residential buildings in Cairo using life-cycle cost analysis. An extensive variety of façade retrofit alternatives was explored individually and combined. A hypothetical benchmark building was used as a reference to represent typical residential buildings in Cairo. DesignBuilder was adopted to assess and quantify the energy-saving potentials for the proposed measures. The evaluation process was based on a parametric analysis of four major façade parameters that are affecting building energy performance; exterior wall configuration, glazing type, window-to-wall ratio and external shading. Thermal characteristics for façade retrofit measures were analysed to give a better understanding of the thermal performance for each retrofitting case. Results showed that the most cost-effective alternative for façade retrofit is to install a 1 m overhang as an external shading device, which reached 1.4% life-cycle cost saving and 18% energy saving. Finally, a sensitivity analysis for the main life-cycle cost supplements was presented to show major variables that are affecting life-cycle cost analysis.

Prediction and Optimization Analysis of the Performance of an Office Building in an Extremely Hot and Cold Region

“…Secondly, increasing the WWR_S and decreasing the WWR_N and WWR_E of a building is critical to improving building performance. Literatures [37,98] are more consistent at the level of performance sensitivity analysis compared to the results derived from the optimization in this paper. It can be seen that window performance and the WWR of a building have a very significant effect on building performance, so more attention should be paid to this aspect in future research.…”

“…Kazem et al went on to explore the effectiveness of energy efficiency retrofits in Cairo buildings through a whole-life-cycle cost analysis. The results showed that the most cost-effective façade retrofit was the installation of 1 m long external shading facilities, which reduced LCC by 1.4% and energy consumption by 18% [37]. Weerasinghe et al went on to analyze the impact of green building costs in Sri Lanka by examining the life cycle costs of the building in its aspect.…”

“…In this case, when the entropy-based Topsis method is used, the optimization results in a reduction in the TEUI, GWP, and LCC of 41.94%, 40.61%, and 31.29%, respectively. Literatures [37,98] used the entropy-based Topsis method to go for the effect of optimization of building energy efficiency in extremely hot and cold regions and severe cold regions, respectively. In the above optimization results, in terms of building performance improvement strategies at the level of the building envelope, at the level of the building shading measures, and at the level of the building's thermal insulation performance, the method objectively evaluates and measures the optimization results to quickly and efficiently improve the building's performance potential.…”