Comparative analysis and evaluation of innovative building concept models in terms of key ecological and economic figures during life cycle of individual building concepts
Contents and goals
The controversial issue which construction type in combination with which energetic standard and which building equipment and appliances will prove itself to be environmentally the most friendly gave birth to the idea of a comprehensive comparison of the variant types. The main focus was on creating an objective knowledge base by an extensive project consortium consisting of key building material experts from ACR – Austrian Cooperative Research in collaboration with external experts from the Austrian construction industry to work out the individual calculation of costs as well as independent consultants to carry out the life cycle assessments.
Methods of treatment
The four main construction types (brick, concrete, wood-chip concrete and prefab timber wood construction) were combined with so far well-established energetic standards for new buildings. In addition the studies were stretched out over different systems of building equipment and appliances (wood pellets heating, heat pump, solar heating, photovoltaics etc.). These combinations finally led to 45 building types, the configuration of which was set up on a standard plan lay-out. The environmental impacts of all these building types were evaluated in an ecobalance (LCA) based on an assumptive life time of 100 years and their costs calculated by cash method over an accounting period of 50 years (LCC). The results were expected to answer the above mentioned questions.
The chosen building types were calculated with the help of programs used for energy performance certificates and their superstructures standardized for a uniform heating demand. On the basis of the plans provided for each building type and its energetic standard a big construction company compiled service specifications for the buildings, their equipment and appliances, electro-techniques and sanitary accessories, containing quantities, units and standard prices. After a check-up the ecobalance was set up with the help of tabulation and life cycle costs calculated.
Results and conclusions
The balance sheets show that none of the building types offers a clear answer for the questions put forward. As a whole the building materials used have only little influence on the total result. The energetic standard, however, seems to affect the result substantially. The results with respect to environmental indicators vary due to different utilities management systems, an explicit answer in favour of or against a certain variety cannot be given here either.
At first sight this results seem to be very disappointing, but at a second glance it prove to be satisfactory. If a high efficiency standard in energy demand (total energy efficiency) is obligatory for new buildings, it’s the right direction. And this implies that we have done nothing wrong while adhering to low-energy, solar-energy, passive house or positive energy building standards. The question remains for which site and needs in which circumstances an object is planned, and additionally we should focus on the security in use of the utilities as well as to the user behaviour. Only in that case efficiency figures calculated in theory can be reached in reality.
The collaboration between the institutes and experts enhanced the transfer of expertise and networking opportunities between the individuals and institutes. It also used the host of networking contacts to companies in the Austrian housing and construction industry for dissemination of the results. The relevant target groups were found in the building industry in the areas of service, process and system creation and among building product manufacturers as well as in SMEs in the Austrian real estate industry. Other industries to benefit from the results include the housing industry, whose ecological requirements – particularly in terms of the development and market penetration of innovative solutions that can be implemented economically – are constantly growing.
FGW, Forschungsgesellschaft für Wohnen, Bauen und Planen