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To create a 鈥渓iving building鈥� at the Georgia Institute of Technology, PAE Engineers faced a tall order. Living Building Challenge standards require that such structures be net-positive in terms of energy and water use, and that is a severe challenge in the hot, humid climate of Atlanta.

鈥淔rom an engineering standpoint, humidity is the hardest part to deal with there,鈥� said Marc Brune, an associate principal with PAE Engineers, which is serving as the project’s mechanical, electrical and plumbing engineer. 鈥淚t’s a lot different than the Pacific Northwest.鈥�

The standards for a living building require it to produce 105 percent of the electricity and water it uses annually. Achieving that can be difficult in an environment where summer nighttime temperatures often don’t drop below 70.

The first priority is keeping hot, humid air out and cool, dry air in.

鈥淭here is a lot of energy that goes into wringing the water out of the air,鈥� Brune said.

The project team also needed to limit infiltration. The $15 million building will include a 200-seat auditorium; at each class change, students and teachers will enter and leave, cool air will escape and hot air will enter.

The solution to keep hot, humid air out includes an air curtain within a vestibule. Students will be showered with air as they enter and leave the building. Designers are combining that feature with cooling floors, dehumidification air handlers and a closed-loop geothermal heat pump system to keep the building comfortable.

Energy use is another problem. Figuring out how many laptops and phones might be plugged into charging stations in a given day is a huge challenge.

鈥淭he intent is to prove this can be successful,鈥� said John DuConge, Georgia Tech senior project manager. 鈥淕eorgia Tech has a track record for sustainable projects.鈥�

The plan is to use approximately 17,000 square feet of photovoltaic panels to meet the building’s predicted energy demand.

鈥淧roducing more energy than we consume over the course of a year is an enormous challenge,鈥� DuConge said. 鈥淭hat is something you don’t typically see.鈥�

The project team also sought to recover as much water as possible from the structure. The one advantage Atlanta has in that respect is that rainfall there is fairly consistent.

鈥淭hey get rain all year long,鈥� Brune said. 鈥淗ere we get more rain, but we have several months of drought.鈥�

The team is designing a cistern that will be able to withstand a drought equal to the worst the region has experienced in the past 40 years, according to Brune.

鈥淭he way the cistern is being sized is to look at 30 to 40 years of rainfall data,鈥� he said. 鈥淲hat are the worst droughts that happened? We need to be able to deal with that.鈥�

Designers also have to be careful what they use. The Living Building Challenge includes a 鈥渞ed list鈥� of chemicals that may not be used. Many of the chemicals are found in everyday items.

鈥淭hey are things we commonly find in off-the-shelf products,鈥� DuConge said. 鈥淔or instance, we have to find things that are PVC free. PVCs are pretty ubiquitous.鈥�

If team members can’t find a product that doesn’t have PVCs, they have to argue for a change. The goal of the project is to make a building that is both comfortable and sustainable.

鈥淲e are trying to use things that are healthier,鈥� DuConge said.

Brune said that one of the goals for the engineers is to prove that sustainable, comfortable buildings can be built no matter the environment. Currently, such buildings are only in the Pacific Northwest and Northeast.

鈥淚t is pretty powerful,鈥� he said. 鈥淚t shows that we can be doing things differently.鈥�