Implementing multi objective genetic algorithm for life cycle carbon footprint and life cycle cost minimisation: A building refurbishment case study

Yair Schwartz,Rokia Raslan,Dejan Mumovic

doi:10.1016/j.energy.2015.11.056

Abstract

Early design decisions made by architects have been shown to significantly impact the energy performance of buildings. However, designers often lack the resources or knowledge to take informed decisions that might improve building performance. The refurbishment of existing buildings is considered to significantly contribute to the reduction of the life cycle environmental impact of buildings. Building refurbishment is also seen as the most cost-effective way of achieving this goal. In assessing the life cycle impacts of constructing and usage processes of buildings, LCA (life cycle analysis) is often used.In order to simplify the decision-making process in early design, this study uses MOGA (multi objective genetic algorithms) to find optimal designs for a refurbishment of a residential complex case study, in terms of LCCF (life cycle carbon footprint) and LCC (life cycle cost) over an assumed life span of 60 years.Results show that utilizing MOGA has the potential to reduce the refurbishment LCCF and LCC. Findings emphasize the life-cycle impacts of insulating thermal bridges and the importance of using different heating systems and fuels. Finally, in comparing LCA with more commonly used performance-based decision-making design procedures, the study highlights that employing these distinctive methods can lead to different design solutions.

Highlights

Energy consumption in the built environment accounts for approximately 40% of the total energy consumption in the UK
The outputs of LCA studies are a combination of a range of environmental impacts, in buildings these impacts are often converted to CO2e (CO2 Equivalent) to evaluate the building's GWP
This study focuses on a specific section of the complex comprised of two similar blocks with different orientations (Fig. 3) -a north building (A) and a south building (B) As different orientations can lead to differences in OE consumption, the study set out to examine the performance of the refurbishment of both buildings separately, and to determine how orientation impacts building LCCF

Summary

Introduction

Energy consumption in the built environment accounts for approximately 40% of the total energy consumption in the UK. Improving the energy performance of existing buildings, while keeping additional CO2 emissions and cost to a minimum, has become a key concern and challenge in reducing the life cycle impact of buildings. The outputs of LCA studies are a combination of a range of environmental impacts, in buildings these impacts are often converted to CO2e (CO2 Equivalent) to evaluate the building's GWP (global warming potential). This single value describes the LCCF (life cycle carbon footprint) of the building, which enables the direct evaluation of environmental impacts of alternative solutions. Carrying out an LCC can help in the determination of a building's lowest life cycle cost [10]

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Results

Conclusion