Get Sust! Issue 31

Genetic algorithms make whole life choices clearer

Researchers in Belgium have developed a new way to analyse the whole life performance of extremely low energy dwellings, taking into account energy use, environmental and ecological impact, and financial costs.

Ultra-low-energy dwellings - such as passive houses and energy autarkic buildings (which are completely disconnected from any external supply network for either energy or water) - incorporate numerous technologies, each of which could potentially contribute to much more embodied energy and more embodied pollution to the overall project. But it is also possible that more resources are needed to produce and maintain these technologies and they may be more expensive to build. Thus, although these experimental buildings have much smaller energy consumption during the usage phase, such projects hardly ever show clearly whether the global balance of energy, ecology and costs is finally positive.

Traditional life-cycle analysis techniques are insufficient to deal with this increasing complexity. So the researchers, led by Griet Verbeeck of University College Provinciale Hogeschool Limburg, have developed a technique based on genetic algorithms (GA) - a computation technique that mimics the biological natural selection process i.e. ‘survival of the fittest’ where, of course, we’re correctly talking about ‘fittest’ in terms of ‘most appropriate’.

In their report, published in the latest issue of Journal of Building Physics the researchers say that one of the main advantages of this strategy is that little mathematical detail is required.

The methodology consists of three pillars: a multi-objective optimisation based on GA, a model for life cycle inventory (LCI) for buildings, and a model for cost assessment.

Their paper presents the results of a whole life assessment of a typical (Belgian) terraced dwelling over a 30 year life-span, taking account of likely energy cost changes over that period.

Learn more:

	•	Life Cycle Optimization of Extremely Low Energy Dwellings, Griet Verbeeck and Hugo Hens, Journal of Building Physics 2007; 31; 143 (DOI: 10.1177/1744259107079880)
	•	Read the full paper - available free of charge until 30 November - at http://jen.sagepub.com/cgi/content/abstract/31/2/143.