Exergy-Based Calculations of a Building’s Lifetime Energy Usage and Emissions Improve Environmental Decision-Making
This algorithm calculates a building’s energetic quality, its material resource use, and its environmental impact over its life cycle. Building construction and operations make up 36 percent of global energy end-use and 40 percent of energy-related carbon dioxide emissions. Reducing the energy consumption and emissions of buildings through informed decision-making in the blueprinting phase is therefore a focus in preserving environmental health. Contractors commonly perform a Life Cycle Assessment (LCA) to measure the environmental impacts of building designs, but these assessments do not accurately account for resource depletion, plus lack standardization and have the potential for subjectivity.
Researchers at the University of Florida have developed an algorithm to improve LCA that measures the “exergy,” or energetic quality, of resources used and emissions produced in constructing and operating a building. Exergy-based LCA more accurately calculates a building’s energy-related environmental impacts, reduces subjectivity, and allows for easier comparison between LCAs of different buildings.
Application
Exergy-based life cycle assessment of building resource use and emissions to help builders make more sustainable designs
Advantages
- Factors in the energetic quality of depleted resources and emissions, improving life cycle inventory data for better environmental impact projection
- Eliminates need for normalization and weighting of indicators, reducing the subjectivity of sustainability assessments
- Expresses total environmental impact as a single objective function, standardizing comparisons between assessments of multiple buildings
- Applies to a variety of structures including bridges, buildings, parking decks, houses, etc.
- Facilitates calculation of downstream maintenance costs or environmental taxes, informing monetary plans for a building’s sustainability
- Algorithm may be applied to older buildings to make sustainable implementations (e.g. as energy-efficient windows)
Technology
The algorithm uses data from the conventional life cycle assessment (LCA) of a building to determine more accurately its environmental impact based on the energetic quality of the building’s emissions and depleted resources. The automated computation tool employs life cycle inventory (LCI) data to perform a holistic exergy-based LCA to determine the primary exergy demand, material exergy demand, and exergy loss of emissions. The final comprehensive assessment of resource use and emissions can better inform decisions concerning social and economic sustainability factors such as labor and capital.
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