Modern technology is helping us develop innovative ways to produce alternative energy. Solar and wind energy are good examples, although the idea of tapping the sun and the wind for light and heat is hardly new.
What’s new is the ways we’re using them.
Back in the days before electrical power was widely available in rural areas, farmers in the Prairie West used windmills to operate pumps so they could water their livestock.
Back in those days, you could see wind chargers mounted on rooftops.
When the wind blew, they would charge the bank of batteries that powered the household. They didn’t gain wide acceptance, though. Battery technology wasn’t as good as it is now.
Solar energy is even older. People have known for generations that stone houses absorbed heat all summer long, which helped warm the house when the weather turned cold.
Now a small start-up in Nebraska has installed a 14-storey "energy column" in an apartment building in Omaha.
It makes use of a concept that was understood in the Middle East and Europe centuries ago.
While it was used then as a passive form of cooling and ventilation, the Omaha project is using it to generate electricity to power the building.
Construction people have long understood the stack effect.
Warm air rises within the building while cooler air rushes in at ground level to replace it. It’s one of the design factors considered in tall buildings.
What GRNE Solutions has done is take advantage of that stack effect by installing an enclosed column in a corner of the building’s lobby. It’s framed in stainless steel and panelled with sheets of transparent polycarbonate. At the bottom, a turbine spins as the relatively cool air at ground level rushes into the column and rises up the stack to an exhaust vent on the roof. That generates electricity to help power the building.
Jess Baker and Eric Peterman, who co-founded GRNE Solutions, call their system an "energy column." Older systems that simply ventilate have been known by several names over the centuries, but most often they were called solar chimneys.
In its simplest form, a solar chimney consists of a chimney painted black.
During the day the sun’s energy heats the chimney and the air within it. That heated air rises, creating suction at the base, which pulls cooler air into the chimney.
Such structures were known and used by the ancient Persians in the Mideast.
Nowadays, we have proposals for "solar updraft towers," which would employ the same principles as the Omaha project, but with a dozen or more turbines around the perimeter of the tower’s base.
These proposals—in Texas, Arizona and Australia—are for immense, utility-scale structures. But they bring high up-front costs with them, which is why none have yet been built. As interest in sustainability has increased, so, too, has interest in solar chimneys.
For example, a heat pump could provide relatively cool air into a building, then the stack effect could exhaust the warmer through a modern version of a solar chimney. It’s a neat solution that takes advantage of the fact that you don’t have to drill very deeply to find temperatures that are pretty well constant all year.
Such a system could be used to warm a building during the winter simply by closing the damper on the chimney.
The Omaha project, say its installers, is intended mostly to prove the concept of this modern adaptation of solar chimneys. They will be using it as a test bed, to test such things as the configuration of the turbine blades, and the location of the turbine, or turbines, within the tower.
Old as it is, the concept of solar chimneys can still be improved to help us protect our environment by using renewable energy.
Korky Koroluk is an Ottawa-based freelance writer. Send comments to editor@journalofcommerce.com.
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