Life-cycle assessments (LCAs) of buildings are an important tool, but they generally occur after the design process is finished, when it’s too late to make significant changes. But a team of MIT researchers has developed a tool that lets architects perform LCAs easily as part of the design process, without significantly impacting creative freedom.
Life-cycle assessments look at the cost (financial and/or environmental) of a building through all the phases of its life, from construction all the way to dismantling or repurposing. These costs include the energy embodied in the materials used to make the building (i.e., carbon emissions from concrete production) and the power sources needed to heat and cool the building.
Usually, the life-cycle analysis is performed after the building is already designed, with architects making minor tweaks or adjustments to the building to lower its lifetime costs. The researchers who developed the Building Attribute to Impact Algorithm (BAIA) system wanted to change that. Their early-design, parametric LCA tool considers factors like location/climate, building dimensions and orientation and climate control, and helps architects select environmentally optimal solutions.
Initially, the researchers were worried that an early-in-the-process LCA tool might restrict architectural creativity, and that architects might balk at that. “Our theory is that any designer doesn’t want to be told that this is how the design must be,” said Randolph Kirchain, one of the study’s authors. “Their role is to design without undue constraints.”
The researchers decided to test the question of how much their tool restricted design by developing a measure they call “entropy,” where higher entropy represents a greater range of creative freedom. They then ran design tests with BAIA to see how much it restricted designer freedom.
The result? While creating perfectly optimized designs reduced design flexibility, searching for 75 percent optimized designs did not. “That’s the most remarkable result [when calculating the LCA at the beginning of the design process], you barely touch the design flexibility,” said Franz-Josef Ulm, another study author. “I was convinced we would come to a compromise,” where design flexibility would have to be limited in order to gain better life-cycle performance, Ulm said. “But in fact, the results proved me wrong.”
There’s still a lot more the researchers want to do with BAIA. Currently, their software is meant to optimize relatively simple single-family buildings, but they would like to see if they can modify it to optimize apartment housing and industrial buildings. They also want to include it as a plug-in for commonly used architecture software. Finally, they are interested in BAIA as a tool for estimating life-cycle costs as well as life-cycle environmental impact.
Read the full paper, published in the journal Building and Environment, here.