Not only is the newly designed SunCatcher for Scottsdale, Ariz.-based Stirling Energy Systems, or SES, now closer in shape to an actual dish, but it uses 2 tons less steel.
This, according Sandia National Laboratories scientist Chuck Andraka, whose laboratory designed the system, is what sets the newest generation of solar dishes apart from their predecessors, and it’s an important factor in making commercial solar energy as affordable as conventional energy sources like coal, oil and gas.
But it’s not just the use of less steel. Overall, the design is fully 5,000 pounds lighter than its prototype, making it easier to transport and install, and the new shape – closer to a satellite dish – allows the same structural resistance with less steel.
About 37.5 feet in diameter, the SunCatcher’s new design doesn’t enhance solar performance, but with fewer pieces it does make manufacturing easier, faster and less expensive, and the new dishes – which should start appearing next year – should, by virtue of lowered costs, attract more interest at the commercial solar level.
The less complicated SunCatchers also make servicing easier, reducing times from a week to a few hours, and the parts – steel, mirrors and glass – are also integral to the auto manufacturing sector, which means suppliers in the newly downsized auto industry could revamp production lines and get back in business rather rapidly.
The SunCatchers also use automotive-type closed-loop radiators for cooling, which represents another manufacturing opportunity.
The new SunCatcher design is the result of a cooperative effort between SES and Sandia National Laboratories, which began working on the project in 2002. In 2003, SES brought in a dish manufactured by another firm, but by 2005 was able to install an SES-built (and Sandia-designed) prototype which led to the current design standard.
Each SunCatcher produces 25 kilowatts of electricity. Placed in solar arrays covering many acres of otherwise unused land, these solar “farms” are potentially able to deliver real power. Currently, according to the Pew Center on Global Climate Change, all forms of solar generation (concentrating, utility-scale and distributed generation) provide only 0.5 percent of the entire generation mix, or 3 terawatt hours per year (TWh/yr) as compared to natural gas, which generates 685 TWh/yr.
The SunCatcher works as a solar concentrator, focusing solar radiation via mirrors attached to a parabolic dish on a receiver, which transmits the heat to a Stirling engine (a self-contained system filled with hydrogen gas).
As the hydrogen heats and cools, the changes in pressure drive a piston inside the engine that produces mechanical power, much like a piston in an automobile engine. In the Stirling engine, however, the mechanical power feeds a generator making electricity.
As improvements in weight, design and manageability overhaul prospects for the commercial solar energy sector, more investors express interest. This, according to Andraka, is where the bulk of the investment is coming from, not from the government, because investors understandably want results; that is, a return on investment. And SES’ new, simplified and lighter SunCatcher appears designed to deliver just that.