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Optimization of Construction Compositions for Design of Green Building
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1  Technical University of Košice, Košice, Slovakia

Published: 01 November 2011 by MDPI in The 1st World Sustainability Forum session Environmental Sustainability
Abstract: Human activities cause climate changes which are now recognized by the global community as the greatest environmental threat of the 21st century. The global climate system is being affected by the emission of greenhouse gases, of which the most significant is carbon dioxide. It is known that the building sector represents approximately 40% – 50% of the total energy consumption and production of emissions in developed countries. The buildings can make a marked contribution to energy and carbon conservation during all phases of their lives by sophisticated building design. It is recognized that operational energy analysis has dominated building energy research for many years when compared to embodied energy analysis. However, it has been shown, that the building becomes more operationally energy efficient, the embodied energy to operational energy ratio increases. The embodied energy and emissions are therefore likely to account for an increasingly large proportion of building-related life cycle CO2 eq. emissions in the future. The importance of embodied energy and CO2 eq. emissions analysis should therefore not be underestimated when assessing life cycle energy requirements, resource depletion and related environmental impacts. The study presents analyses of significant environmental indicators of different structural solutions of residential building in the paper. The results of analyses show how lower the energy demand and the carbon footprint of building can be reduced by increased use of sustainably sourced timber and nature building materials on vegetable base acting as a long-term carbon store. The environmental quality of the building materials in construction variants was evaluated by methodology LCA. The study was also evaluated thermo-physical data of construction solutions used in residential building for climatic conditions of Slovakia. The construction variants were compared in order to assure positive effect on the energy balance of operation of residential building and results in better passive control of summertime overheating. The aim of multicriterial analysis was to create high energy effective building constructions with minimal value of embodied energy and which act as a carbon store. The environmental and physical comparisons of the building construction variants were calculated in order to optimization of design of green house which is environmental evaluated by partial analyze of LCA at the conclusion of the paper.
Keywords: constructions, embodied energy, emissions, LCA
Comments on this paper
Yvan Dutil
Embodied energy and CO2
Very nice work. I would like to point out that in modern energy efficient house embodied energy is a very significant fraction of the overall energy consumption (Dutil et al. 2011). In consequence, your work is very important. However, I have some doubt about the usage of organics construction materials to sequestrate the carbon. Practical house lifetime is not much larger that the trees lifetime, which raises doubt about the effectiveness of this strategy.

Monika Culakova
The tree absorbs a lot of CO2 emissions during its growth; however its ability of absorption is decreasing by the trees age. When an old tree (around 50-70 years) is used in building constructions, it can serve as a long-term carbon store. The wood–framed houses with straw bales can reach the long lifetime when they are designed correct, e.g. they are protected against wind-driven rain thanks to wooden paneling and overhangs of roof and they must be protected against ground moisture and so on.

A straw-bale wall rendered with the earth plaster is neutral and improves the indoor environment through its ability to regulate interior moisture (Wihan 2007, Minke 2006).
Furthermore the straw bales are cheap insulation material. If the straw bales were not used in constructions, they would be rotten and CO2 emissions would be released sooner.

In effect it is fully possible to build a building with straw bales as a biodegradable house, all depending on the overall design and selection of additional materials for the building construction (Wimmer et al 2004). If this kind of building is rendered with an earth plaster it becomes almost completely degradable. This ensures a CO2 neutral material, which may be CO2 positive as it replaces other materials with a high value of embodied CO2 (Rowan, 2007).