solar_air_chimney
Art Burtis' solar air chimney uses heat from the sun to move massive amounts of air. If built, the device could support carbon capture systems, spin turbines and condense water vapor from the air.   David Briggs

A mason in San Geronimo has developed a prototype for a giant chimney that moves massive amounts of air using heat from the sun, a device he believes could be instrumental in fighting climate change.

Art Burtis, a valley resident for 24 years, says the air movement created by his chimney can be used for carbon capture systems, which separate carbon dioxide from the atmosphere when air passes through, like a filter. The separated CO2 could then be used as a base material in fuel for any combustion engine, creating the potential to reverse climate change without disrupting the global economy.

It’s a concept Mr. Burtis has been working to develop since 1992. “Air is one of the most powerful items on the planet when it moves,” he said. “What I’ve done is I’ve put it in a specially designed chimney system that operates off of the heat of the sun. I control the air flow, and I make it move fast and in great mass.”

The idea to use rising hot air to generate electricity has been around for over a century, but Mr. Burtis’s idea was inspired by the hundreds of standard chimneys he designed in his 40-year career as a builder. At one point he was hired to build Trombe walls, a patented design that uses the sun to passively heat the inside of a home. It helped him understand the power of moving air.

Mr. Burtis now has a nine-foot tall prototype of the Solar Air Tower Chimney; a working one would be between 30 and 700 feet tall and its ideal location is a desert. Below  the chimney’s base, a translucent material that captures heat spreads out in a canopy mounted horizontally about five feet off the ground. As the sun heats the air beneath the canopy, the hot air rises toward the chimney, where it reaches a point of constriction. 

Here, the design relies on the venturi effect, by which the velocity of a fluid or gas increases as its movement is constricted. (The effect is visible when you put your thumb over the end of a hose to increase water speed.) Once the hot air is constricted at the chimney’s base, it shoots up at rapid speeds.

The walls are made of fabric supported by poles and wires, and interior walls would guide channels of air with different temperatures, speeds, pressures and direction, leading to even more airflow. (The precise materials and interior design are trade secrets.)

The structure has the potential to move more air faster than any other device, Mr. Burtis said. Turbines could be placed horizontally in the chimney and spin without wind, generating electricity. And because the air on the inside of the chimney is a different temperature from the air on the outside, water vapor could be condensed into potable water.

Mr. Burtis has hosted discussions and met with industry leaders in the field of carbon capture to ensure their inventions are compatible with his design. At the lab of Klaus Lackner, the director of the Center for Negative Carbon Emissions at Arizona State University, he learned about a filter that can collect CO2 molecules as air passes through it.

Carbon dioxide collection systems need to make contact with a lot of air, Mr. Lackner explained. Most of these systems actively fan the air, he said, but Mr. Burtis’s chimney moves air without relying on electricity.

That the captured CO2 could be used as a base material in hydrocarbon fuels that work in any combustion engine is a key feature for Mr. Burtis, as it gives energy companies an incentive to build the chimneys and reduce the amount of CO2 in the atmosphere.

“How could we take down the oil companies, with everything they contribute for our day-to-day life?” asked Linda Jannsen, Mr. Burtis’s wife, who manages the administrative side of the company. “It would be nice if everybody could get an electric car, but still we’ve got a whole other set of problems with that because of the batteries.”

Instead, Ms. Jannsen and Mr. Burtis believe the solution is for governments to invest in sustainable technology with the urgency of going to war.

Before a large-scale prototype of the solar air tower chimney can be built, Mr. Burtis needs a significant investment from a government entity or large energy company. A full-size chimney would cost at least $3 million to build, though once the infrastructure is in place and the wrinkles ironed out, capital costs would fall and hundreds could be built, he said.

As someone who has been following climate change since well before the issue entered the zeitgeist, Mr. Burtis understands the global systems and cycles that have been thrown out of balance, from ocean currents to Arctic albedo. He said he used to tell people that the earth was overheating, and they reacted with apathy. But lately, he’s noticed an increase in the realization that something needs to be done, which is why this year he plans to circulate his chimney as much as he can.

“Now that the people are beginning to agree that something has to be done, it is the people that will create the momentum to make this happen and force the governments to fund it,” he said.