Gary Conley, the entrepreneur who founded concentrating solar company SolFocus, is at it again. Last month he launched b2u Solar, a startup which uses the sun’s heat for industrial applications like drying, curing and commercial baking, and is one of a crop of startups working to take advantage of the higher efficiency potential of heat compared to electricity.
At the Cleantech Forum in San Francisco last week, Conley claimed b2u’s technology can deliver the equivalent of 40 to 60 cents per watt – and 2.5 to 4.5 cents per kilowatt-hour – by generating heat directly, instead of producing energy that is then used to make heat. That makes it potentially competitive with natural gas today, and the economics look even better if the heat is also used for air conditioning, as well as heating, Conley said. (It may sound counterintuitive, but heat can be paired with a chiller to generate cool air).
Other solar companies that are developing ways to utilize the sun’s heat include Sopogy, which installed its first commercial project in Hawaii last year, Focal Point Energy, which is developing systems that produce hot water and steam for industrial applications, HelioDynamics, Chromasun, and the Center for Architecture Science and Ecology.
These solar heat systems are generally based on the same type of technology as the big projects that BrightSource Energy, Abengoa Solar and others are installing in the desert. A reflector directs the sun’s heat to a tube in which fluid circulates, and the hot fluid then provides heat for other applications.
But companies like b2u Solar are working to make the systems viable for applications that can use the heat directly — and at smaller sizes so the systems can be installed where the heat is used, avoiding transmission losses. In b2u’s case, the design utilizes an evacuated tube collector, normally used for hot water heating, and Conley claims the system can capture and convert diffuse light, not just direct light like most concentrators.
B2u’s technology generates heat of between 135 and 200 degrees Celsius. But one issue with these types of technologies has been the difficulty of using all of the heat. Even though making heat is cheaper than producing electricity, “if a system generates more heat than [a customer] can use, that’s not a payback,” said Jenny Chase, lead solar analyst at Bloomberg New Energy Finance. Solar-thermal cooling has proven more difficult than expected, with Chase saying she has yet to see a company make it work on a commercial scale and volume.
B2u believes its ability to use diffuse light will allow it to tap into the elusive cooling market. A case study comparing production on a cloudy day with a sunny day found only 16 percent lower production on the cloudy day, Conley said. And a demonstration project has been cooling successfully since Dec. 1 at a third of the current electricity cost for air conditioning during the day, he added.
With that ability, along with its temperature range, b2u believes its technology has plenty of industrial applications, including concrete curing, paper finishing, wastewater treatment and commercial cooking. “ConAgra drying onions and garlic for McDonald’s – that’s the temperature range you need,” Conley said. The company also hopes to replace some of the natural gas used to inject water for oil production, he said, and has just bid on one such project in the Middle East. All together, b2u estimates its technology could potentially address 30 percent, or $90 billion, of the market for industrial process heat and commercial heat.
B2u, which is seeking $6 million to $8 million in its first round of funding, is in final negotiations with contract manufacturing partners and plans to begin shipping commercial collectors in the second quarter of this year, said Conley. The company already has several demonstration projects installed in China and the United States, including one at the NASA Ames Research Center at Moffett Field, Calif. that has been running for nearly two years. B2u also has formed a partnership with the Gas Technology Institute, a nonprofit to develop new energy technologies, and, together with its partner, won a $400,000 grant from the California Energy Commission for a demonstration project in Southern California.
Image courtesy of Sopogy.