More By This Author

Current Issue

Current Issue

Posted: March 27, 2013

Tech startup: Cool Energy Inc.

Eric Peterson

INITIAL LIGHT BULB Sam P. Weaver founded Cool Energy with his father, Sam C. Weaver, and his brother, Dan Weaver, after a Christmas toy provided inspiration.Sam C.’s background in nuclear energy led to a longstanding family conversation on how power plants and industrial facilities could reclaim waste heat and convert it to electricity. Then came Christmas 2005 and the American Stirling Co.’s coffee cup Stirling engine. Robert Stirling’s eponymous engines converted waste heat into mechanical energy during the Industrial Revolution, and the toy turned the waste heat from a cup of joe into 250 revolutions per minute. It captivated the Weavers. Cool Energy now has seven employees, with Sam P. Weaver serving as CEO and his father as chairman of the board. (Dan Weaver is an investor.)

IN A NUTSHELL Cool Energy was born from the idea for a low-temperature Stirling engine that didn’t require combustion. The result of five years of research and development, the company’s SolarHeart Engine converts low-temperature waste heat into electricity to be used onsite or sold back to the grid. After four prototypes that advanced the concept from 30 watts to 3 kilowatts, Cool Energy’s final 20-kilowatt prototype is currently in the design phase, and Weaver says he expects to build it in early 2014 and subsequently scale up production. Thanks to better materials and more surface area to facilitate heat exchange, existing SolarHeart Engine prototypes operate at about 22 percent efficiency at 300 degrees Celsius, a breakthrough number that Weaver only sees increasing with the 20-kilowatt version. “What’s nice about it is it will cost about 2 ½ times as much to build, but it produces seven times as much electricity,” says Weaver, describing “economies of scale” for larger engines. Ultimately, Weaver says Cool Energy’s technology could reduce fossil fuel use by 10 percent worldwide if it was applied universally to engines of all kinds.

THE MARKET Cool Energy’s target customers include everything from coffee roasters to ceramic and cement manufacturers, as well as oil and gas fields. As the SolarHeart Engine will run $60,000 installed, the payback cycle could be as little as two years in markets where energy is most expensive. “The most lucrative markets look like they’ll be in Europe,” Weaver says. Before scaling up production, he says he hopes to license the design to manufacturing partners.

FINANCING Cool Energy raised $1 million from California-based Idealab in 2011 while also landing about $1.8 million in government grants. Weaver says the company is in pursuit of an investment of about $5 million more to launch production.

where Boulder    |    FOUNDED 2006    |   web

Denver-based writer Eric Peterson is the author of Frommer's Colorado, Frommer's Montana & Wyoming, Frommer's Yellowstone & Grand Teton National Parks and the Ramble series of guidebooks, featuring first-person travelogues covering everything from atomic landmarks in New Mexico to celebrity gone wrong in Hollywood. Peterson has also recently written about backpacking in Yosemite, cross-country skiing in Yellowstone and downhill skiing in Colorado for such publications as Denver's Westword and The New York Daily News. He can be reached at

Enjoy this article? Sign up to get ColoradoBiz Exclusives. The opinions expressed in this article are solely that of the author and do not represent ColoradoBiz magazine. Comments on articles will be removed if they include personal attacks.

Readers Respond

Commenting is not available in this channel entry.

ColoradoBiz TV

Loading the player ...

Featured Video