Using Space Age Engines To Alleviate Poverty

By Jacqueline Callihan

NASA's exacting standards require a power generator to run for 17 years on deep space missions with high efficiency, low weight, and zero maintenance. For this, they turned to Stirling engines made by a Kennewick, Wash. company called Infinia Corporation.

Infinia's Stirling engines have only two moving parts, have no friction, and require no oil, making them entirely maintenance free. "We design and fabricate them, assemble, weld shut, and then send them off for their useful life,” says Jim Clyde, vice president of sales and marketing at Infinia. In NASA's case, 17 years of useful life.

Now, entrepreneurs are developing a new use for these engines as generators of economic growth for villages in the developing world. Last July, Infinia and Emergence BioEnergy Inc., founded by entrepreneur Iqbal Quadir, announced a partnership to help villages derive energy from cow dung using a Stirling engine. The engine produces one kilowatt of electricity, enough to light one hundred fluorescent bulbs, and twice as much thermal energy. When both energy products are used, the engines are more than 90 percent efficient.

Centralized power plants here in the U.S. waste up to 70 percent of produced energy through heat lost into the atmosphere. In the Bangladesh community model, the combined heat and power capabilities of Stirling engines minimize waste. Electricity can be used to power homes, heat to dehydrate crops, and waste created from anaerobic digestion of cow dung can be used to fertilize fields.

Not only will the local economies be able to develop, but they will be developing in an ecologically friendly way. Biogas is produced from cow dung that would otherwise be left in the fields, emitting methane, a greenhouse gas. The biogas is used to fuel the Stirling engines while the waste produced from digestion can be used to fertilize fields for the next year's crops.

In 2005, pilot tests in two villages in Bangladesh demonstrated that Stirling engines would be practical in the rural areas. Some twelve more systems will be tested in the summer of 2008.

Jacqueline Callihan is a Ph.D. student in bioengineering at the University of Washington.

Images:

Top: Schematic of a working Stirling engine. Image: Jeff Schreiber

Bottom: A model of the community uses for the Stirling engines.