Buildings use a lot of energy. Heating and cooling account for much of that consumption, with heat often coming from natural gas and air conditioners relying on fossil fuel-derived electricity. While air conditioners (ACs) have gotten more efficient over the years, they’re still a major source of power usage — one the world needs to address as climate change worsens.
The solution may not necessarily be in new technology but the natural world. Some architects have seen impressive results by creating natural ventilation inspired by nature.
The problem with conventional cooling
Humans need a way to keep buildings cool during the warm months. As the world gets hotter, that may become an even bigger demand, but how most homes and offices approach this is remarkably inefficient. Home ACs consumed a staggering 254 billion kilowatt-hours of electricity in 2020 alone — 19% of houses’ total electrical usage.
Electricity-free ventilation may sound far-fetched, but some projects have already proved its potential.
Commercial buildings tell a similar story. Roughly 14% of their electricity goes toward powering AC systems, and another 18% goes to ventilation once this AC has cooled the air. All this power consumption poses a problem because most electricity today comes from fossil fuels.
As a result, space cooling generated 1.02 gigatons of carbon dioxide emissions in 2022. That’s more than 1 billion metric tons of hazardous fumes entering the atmosphere because of the way humans cool buildings. More worryingly, cooling-related emissions keep growing — they’ve almost tripled since 1990.
The promise of natural ventilation
Energy-efficient AC units would help, but a better option is to eliminate the need for electricity in space cooling. Passive cooling aims to achieve this. Clever building designs could naturally redirect air to keep temperatures low without using much — if any — energy.
Electricity-free ventilation may sound far-fetched, but some projects have already proved its potential. The Eastgate Center in Harare, Zimbabwe, uses 90% less energy than a conventional building to keep cool. It’s able to do this by copying how termite mounds take advantage of hot air rising.
Termite mounds are colder than their surroundings due to a network of tunnels that lets air enter the base and escape through the top. Because air becomes less dense as it heats up, the lower levels remain cool while heat dissipates out the mound’s “roof.” The Eastgate Center applies the same concept with a series of air shafts and vents.
Other structures use a double roof to capitalize on the same idea. The first roof lets hot air escape through a network of vents, while the curve of a second roof above it creates a wind tunnel to blow the heat away. By creating airflow, the design ensures heat keeps moving, cooling the inside more efficiently than a simple hole in the ceiling.
Boosting passive cooling with smart design choices
Passive cooling systems like these are most effective when paired with related design choices. Even something as simple as paint can make a difference. Dark colors absorb much more heat than light tones, so painting interiors near windows a lighter shade will prevent excess heat buildup.
Natural insulation can drive further energy savings, too. Underground temperatures remain relatively constant and are cooler than the air above, thanks largely to avoiding sunlight and changing weather patterns. Buildings can take advantage of this by placing structures into hills instead of on top of them. Covering walls in layers of earth has a similar insulating effect against the heat outside.
Similarly, homes and offices can grow greenery along the outside to foster natural cooling. Plants provide shade and reduce temperatures around them as they draw water from their roots and release it as vapor through their leaves.
What about heating?
Of course, heating buildings in the colder months also deserves attention. Thankfully, there are passive solutions to this problem, too. Solar chimneys are particularly promising.
These structures consist of a large window in front of a dark-painted wall with closable vents at the top and bottom. As the sun shines through the glass, the chimney intensifies the resulting heat. By opening the chimney to the outside at the bottom and opening it to the interior toward the top, this design heats air as it enters and releases it throughout the room once warm.
Even if solar chimneys use fans to facilitate movement, they reduce energy demand by 20% in some cases. These structures can also promote passive cooling in warm weather by adjusting the vents to release outside at the top but open inside at the bottom.
Nature may hold the future of architecture
Cutting-edge technology has done a lot of good for the environment, but it can do more. Taking inspiration from nature can help architects create structures with natural, passive heating and cooling. Relying on these clever designs will reduce energy consumption and related greenhouse gas emissions while keeping everyone comfortable.
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Ellie is a freelance writer as well as an associate editor for Revolutionized. When she's not writing about the latest advancements in science and technology, you can find her playing video games and spending time with husband and their cat.
