Buildings That Suit the Climate and Save Energy

Humans have long used sophisticated heating and air-conditioning technology to adapt to any climate in the world, but at what cost?

Alpha Arsano SM ’17 asked herself that question as she watched more and more skyscrapers rise up in her hometown, the Ethiopian capital Addis Ababa. “They were mimicking the kinds of buildings found in Dubai and other countries,” she says. Building techniques such as earthen walls, natural airflow, and insulation, used for centuries to complement Addis Ababa’s temperate climate, were being abandoned in favor of massive, glass-walled buildings that relied on mechanical systems for climate control. “If I showed you a picture of one of these high-rise buildings, you wouldn’t be able to tell where in the world it was from.”

Then a student at the Ethiopian Institute of Architecture, Arsano began investigating how buildings might become more environmentally sustainable by taking advantage of passive strategies to save energy—including orienting buildings to take advantage of light and air flows and circulating natural air rather than using air conditioning. Her journey took her to a fellowship with a green engineering company in Germany and eventually to MIT, where she is pursuing a doctorate in architecture and building technology at the School of Architecture and Planning.

“Passive strategies cannot be a hundred percent of the solution all of the time,” Arsano allows. However, integrating such strategies with active heating and air conditioning in so-called hybrid systems can dramatically reduce energy consumption and fossil fuel emissions. “The proposal is to find a middle ground.”

Free online tool

Most architects today design buildings that are “climate-agnostic,” Arsano says, producing essentially the same structure for snowy Boston, temperate Addis Ababa, or heat-baked Dubai. Together with her advisor, building technology professor Christoph Reinhart, Arsano has created a new online tool called ClimaPlus to help architects reverse that trend.

Loaded with climate information from more than 2,000 locations worldwide, the tool allows users to explore data related to temperature, air flow, and solar radiation and experiment with different construction techniques to optimize energy usage. “The architect, engineer, and climate scientist can all come together to customize a solution for a particular location,” Arsano says.

The architect, engineer, and climate scientist can all come together to customize a solution for a particular location.

For example, an architect can use trial and error to rotate the orientation of a building, add insulation, change the outside glazing material, and make other virtual adjustments to see the resulting effect on expected energy use. The tool can also help builders save money by translating that energy usage into cost, Arsano says. “An architect sitting in the United States doing a project in Australia or South Africa can use this to get a general, intuitive sense of a location they’ve never been to, in order to choose what kind of a system can work best.”

Currently free online, the tool is also being used in a course Reinhart teaches on environmental building technologies and in a massive open online course sponsored by the MIT Energy Initiative that is available on MITx. “They can use this tool in their education and then when they go into the field, they have much more experience in what might work for different circumstances,” Arsano says.

Whether or not she returns to work in Africa, Arsano says she hopes the ClimaPlus tool helps architects create buildings more suitable to the continent’s climate. Like many parts of the world, Africa is facing massive urban population growth alongside temperature increases due to the effects of climate change, creating a negative feedback loop of more people needing more buildings, which generates more emissions that drive temperatures higher.“There’s an expectation that buildings have air conditioning in every location, and of course, that has an adverse effect on climate,” she says. “Now is the time to rethink how to address these challenges.”

This story originally appeared in the Spring 2021 issue of MIT Spectrum magazine.

Photo of Alpha Arsano by Erin Eve.