Using solar power to add more precision to the tobacco curing process has proven to be a time and money saver in tests at Virginia Tech University and at Clemson University’s PeeDee Agriculture Research and Extension Center in Florence, SC.

Modern tobacco production is often time and labor intensive. Tobacco curing can make or break both quality and profit in a tobacco crop.

Curing takes about 20 percent of variable cost and 15 percent of the total cost of tobacco production.

A new hybrid energy source tobacco barn that uses solar power and propane, under development by North Carolina-based Long Tobacco Barn Company (LTBC), was one of the highlights of a recent Farmer Field Day at the Pee Dee Station.

Speaking at the field day, Clemson Researcher Russell Henderson said, “Tobacco barns currently in use have an insulated curing chamber. The solar powered barn has no side-wall or roof insulation; instead it has an air pocket that collects solar heat. When you walk into the prototype solar barn here in the middle of the day, the temperature is much higher than in a conventional tobacco barn.”

In the solar barn, air comes into the curing chamber from the bottom of the side walls via an opening that runs the length of each side of the barn. 

Air is pulled through the air pocket around the curing chamber and back to the burner. This allows for capture of the solar heated air that is generated in the air pocket, as well as any heat that escapes from the curing chamber.

A new standard tobacco barn costs about $36,000, while $35,000 is the projected price of a comparable sized solar barn. Hopefully, there will be a Federal tax credit of about $7,000, so the net cost of the solar barn should be a bit lower than a standard barn once they get to the market.

Bob Pope, owner and general manager of LTBC in Edgecombe County, N.C., was on hand at the field day to provide more technical details of the solar powered tobacco barns.

"The solar collector that surrounds the curing chamber works passively by conducting heat directly into the curing chamber through the black corrugated steel collector plate that forms its walls and ceiling. It also works actively by pre-heating fresh air used for curing before it enters the barn's propane-fired furnace," Pope said.

LTBC's barn not only uses the cost-free power of the sun, it has been shown to shorten the time the tobacco needs to be dried. The barn accomplishes this by wrapping the curing chamber in a solar air collector. On sunny days, the barn's solar collector maintains a constant temperature of up to 135 degrees Fahrenheit.

David Reed, an Extension agronomist at Virginia Tech, has conducted studies on the solar barn's curing efficiency, specifically testing the pounds of tobacco cured per gallon of fuel used in the curing process for the past three years.