8. Life Cycle Assessment and Optimization Methods. F. Betzler: Sustainable Structures 155

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1 8. Life Cycle Assessment and Optimization Methods F. Betzler: Sustainable Structures 155

2 Life Cycle Assessment and Optimization Methods Today's method for building evaluation Minimization of life cycle costs Minimization of material flow Minimization of land consumption Maximization of flexibility Optimization of the process cycle F. Betzler: Sustainable Structures 156

3 Today's method for building evaluation F. Betzler: Sustainable Structures 157

4 In the context of the passive solar and low energy building research the energy and the primary energy expenditure for buildings since the middle of the eighties were examined. F. Betzler: Sustainable Structures 158

5 Examination method Previous examination methods focused on the energy need of buildings e.g. for heating. The examination of the energy need of building had to be extended as well as the investigation of the impact on the environment during the whole building process. The information about the primary energy and/or grey energy given by producers of construction units is usually outdated. A direct comparison of products is difficult due to the use of different system borders. The original method based on the energy expenditure (input) was therefore replaced by the life cycle analysis (life cycle assessment LCA/ ecobalance =deutsch: Öko-Bilanz) and the associated inspection of the environmental aspects (output). F. Betzler: Sustainable Structures 159

6 Definition LCA A life cycle assessment (LCA, also known as life cycle analysis, ecobalance, and cradle-to-grave analysis) is a technique to assess each and every impact associated with all the stages of a process from cradle-to-grave (i.e., from raw materials through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling). The goal of LCA is to compare the full range of environmental damages assignable to products and services, to be able to choose the least burdensome one. (wikipedia.org 2010) F. Betzler: Sustainable Structures 160

7 LCA parameters For the LCA information are gathered about the transformation of materials and energy (input) of products and services during the entire life cycle of the building as well as for the estimation of the associated ecological effects (outputs). In particular there are five central parameters: - consumption of material resources - consumption of energy - air contamination by atmospheric emissions - material contamination of water - soil contamination by waste and direct emission The economic and social effects are not regarded in the LCA. For this purpose there is a so-called line analysis. F. Betzler: Sustainable Structures 161

8 Products and services are surveyed during the entire product life cycle: the winning and supply of the raw material, the production and processing of semi-finished materials and products, the use of the products and their recycling or disposal. Depending on the definition of the framework even the energy supply, the additives supply, the transport and maintenance in the respective phases are considered. F. Betzler: Sustainable Structures 162

9 Goal of the LCA The goal of the LCA is to minimize the use of resources and the production of emissions. Therefor the material cycle in the building industry should be closed by recycling of building materials and energy. In order to ensure a standardization and comparability of LCAstudies, the procedures of the LCA are regulated in the ISO environmental management standards: in ISO 14040:2006 and 14044:2006. (ISO replaced earlier versions of ISO to ISO ) Die nächsten Folien sind nicht mehr aktuell, da sie von den alten Versionen der ISO-Series handeln! Hab die Folien daher ausgeblendet und andere eingefügt. F. Betzler: Sustainable Structures 163

10 DIN EN ISO series (von mir eingefügte Folie) ISO series (14040 to 14049), Life Cycle Assessment, LCA, discusses pre-production planning and environment goal setting. According to the ISO and standards, a Life Cycle Assessment is carried out in four distinct phases: (wikipedia.org 2010) F. Betzler: Sustainable Structures 169

11 (von mir eingefügte Folie. Zu ausführlich?) Goal and scope definition In order to make efficient use of time and resources and outline how the study will be conducted and what final results will be obtained, the following six decisions must be made at the beginning of the LCA process: 1. Define the goal(s) of the project 2. Determine what type of information is needed 3. Determine the required specificity 4. Determine how the data should be organized and the results displayed 5. Define the scope of the study 6. Determine the ground rules for performing the work The object of study is described in terms of a so-called functional unit. Apart from describing the functional unit, the goal and scope should address the overall approach used to establish the system boundaries. The system boundary determines which unit processes are included in the LCA and must reflect the goal of the study. Finally the goal and scope phase includes a description of the method applied for assessing potential environmental impacts and which impact categories that are included. F. Betzler: Sustainable Structures 170

12 (von mir eingefügte Folie) Life cycle inventory The second phase of LCA involves data collection and modeling of the product system, as well as description and verification of data. This includes all data related to environmental (e.g., CO 2 ) and technical (e.g., intermediate chemicals) quantities for all relevant unit processes within the study boundaries that compose the product system. Examples of inputs and outputs quantities include inputs of materials, energy, chemicals and 'other' and outputs of air emissions, water emissions or solid waste. Other types of exchanges or interventions such as radiation or land use can also be included. F. Betzler: Sustainable Structures 171

13 Life cycle impact assessment The third phase 'Life Cycle Impact Assessment' is aimed at evaluating the contribution to impact categories such as global warming, acidification, etc. The first step is termed characterization. Here, impact potentials are calculated based on the Life cycle inventory results. The next steps are normalization and weighting, but these are both voluntary according the ISO standard. Normalization provides a basis for comparing different types of environmental impact categories (all impacts get the same unit). Weighting implies assigning a weighting factor to each impact category depending on the relative importance. F. Betzler: Sustainable Structures 172

14 Interpretation This stage leads to the conclusion whether the ambitions from the goal and scope can be met. Life Cycle Interpretation is a systematic technique to identify, quantify, check, and evaluate information from the results of the life cycle inventory (LCI) and/or the life cycle impact assessment (LCIA). The purpose of performing life cycle interpretation is to determine the level of confidence in the final results and communicate them in a fair, complete, and accurate manner. F. Betzler: Sustainable Structures 173

15 In order to provide a standard LCA, the steps specified above are necessary. In the building industry there are large material and energy flows and therefore a huge amount of information. The LCA can be accomplished on different levels, depending on the investigation goal: F. Betzler: Sustainable Structures 174

16 Minimization of life cycle costs F. Betzler: Sustainable Structures 178

17 Life cycle costs For the minimization of life cycle costs the total costs for the entire Investment have to be considered: beside the construction costs also the maintenance costs and above all the operating costs (cooling, heating, warm water...). F. Betzler: Sustainable Structures 179

18 Building costs In former times the highest primary energy need of buildings and the associated costs resulted from the heating and warm water supply of the building. Today the highest costs result from production and maintenance: less energy is needed for heating due to better and more complex constructions.. F. Betzler: Sustainable Structures 180

19 Building costs In the graphic the source for the costs are shown. While the Frame construction should at least last 80 years, the technology, the interior fittings etc. must be renewed in shorter periods in order to correspond to the requirements. F. Betzler: Sustainable Structures 181

20 Minimization of material flow F. Betzler: Sustainable Structures 182

21 General principles for above ground construction To recycle/re-use building materials is difficult due to the mix up of different kinds of materials. Therefore following principles should be considered: You tell me... F. Betzler: Sustainable Structures 183

22 Re-use of building materials One possible way is to use parts of old buildings to build new ones like people were using material of ruins of old castles to build new houses in former times. In east Germany in July 2002 already about empty buildings made with precast concrete slabs ( Plattenbau ) were counted, with upward trend. These concrete slabs are high-quality products with a life span of 80 to 100 years. Demolition would mean a high loss of energy: In a building with five levels approx. 1,7 million kw/h primary energy is fixed. For buildings that means a loss of energy that would be enough for the heating of 5000 families over 100 years. F. Betzler: Sustainable Structures 184

23 Minimization of land consumption F. Betzler: Sustainable Structures 185

24 Development of living space needs Per-capita living space needs are rising. The number of inhabitants in Germany increased between 1950 and 1993 by approx. 50 %. In the same time the living space demands have doubled and the energy consumption has become nearly five times higher. The inhabitants of Switzerland have got the highest living space need of Europe followed by German citizen with approximately. The increased living space needs reduce the semi-natural and the agricultural area. F. Betzler: Sustainable Structures 186

25 Von mir eingefügte Folie nach dem deutschen Skript Reduction of land consumption To reduce the land consumption it is possible to use already builtup areas more effectively like an example in Trondheim (Norway) shows: a shopping center was used as a building ground for eleven new appartments in the fourth and fifth floor. A positive side effect is the central location: people don t have to use cars to go shopping so the traffic is reduced. F. Betzler: Sustainable Structures 187

26 Maximization of flexibility F. Betzler: Sustainable Structures 188

27 A building should be designed in a way that it is easy to change without high costs according to the needs of its users. It should breeze according the the temporary use. This flexibility provides a longer existence and like this less environmental impact compared to the construction of a new building. Also the construction and the interior fittings should be changeable. Give some samples that you know... F. Betzler: Sustainable Structures 189

28 Von mir eingefügte Folie nach dem deutschen Skript Change of use There are many examples of a changed use of previous industrial buildings. One example you can see in Oslo: 16 grain silos from 1953 were rebuilt to student dorms with 226 appartments. Due to the re-use of buiding material energy and ressources were saved compared to a new building. The alternative to demolish the silos would bring a lot of construction waste and would waste energy and ressources. F. Betzler: Sustainable Structures 190

29 Optimization of the process cycle F. Betzler: Sustainable Structures 191

30 Process cycle of a building In the process cycle of a building there are five phases: 1. production of materials and storage 2. construction of a building 3. building use 4. demolition 5. recycling and disposal Each phase needs production and transport means, work and energy and produces pollutantas and waste. Production means themselfs like machines or tools and the means of transport need energy during production, pollutants and waste are generated too. F. Betzler: Sustainable Structures 192

31 F. Betzler: Sustainable Structures 193

32 Optimization of the eco-balance The goal of the detailed examination of the five phases is to find criteria for the most ecological arrangement of the cycle, that means for the optimization of the eco-balance. The entire eco-balance consists of the single eco-balances of the five phases and their weightings regarding the total balance. For each phase a separate eco-balance must be generated including the input factors (energy needs) and the output factors (waste and pollutants). Input Output F. Betzler: Sustainable Structures 194