The Heart of Solar Thermal Power Plants: High-power Receivers as Energy Collectors
Dr. rer. nat. Nikolaus Benz (Spokesperson)
Dr.-Ing. Thomas Kuckelkorn Schott Solar CSP, Mitterteich
The fossil fuels oil, gas, and coal are becoming ever more expensive and will someday run out. The future thus belongs to energy production from renewable sources of energy – like solar energy.
But: how can the solar power plants which have been used to produce electricity relatively expensively become competitive?
The first step on this road has now been taken by Nikolas Benz and Thomas Kuckelkorn. The nominated researchers developed a receiver for solar power plants that uses a parabolic trough technology to produce electricity from solar radiation much more efficiently than ever before. Nikolas Benz is Managing Director at SCHOTT Solar CSP in Mitterteich; Thomas Kuckelkorn worked as project manager in development from 2001 and 2006 and got the product ready for launch together with Nikolaus Benz.
Oil absorbs solar heat
The sun sends enough energy in the form of sunlight to Earth every hour to meet the energy demands of man for one year. But the technology needed to exploit solar energy and use it to generate power is costly. A less expensive alternative is the parabolic trough system. In these power plants, numerous curved mirrors capture the solar radiation and concentrate it on a receiver, a tube in which heat transfer oil circulates. The temperature of the oil rises due to the bundled radiation and transports heat to a boiler. The heat produces steam that drives a turbine, producing electricity.
This technology has already been in use for many years in many power plants, for example, in the USA. However: their power efficiency – the percentage of solar energy converted into electric energy – is relatively low. This is what makes electricity generation expensive.
A strong combination of new materials
By combining several innovations, the nominated researchers succeeded in designing a receiver that considerably improves the efficiency of parabolic trough power plants. For one thing, they invented a special glass-metal compound. It produces a stable and vacuum-sealed connection in the receiver between a metal absorber tube in which the heat transfer oil circulates and a surrounding sheath – the vacuum reduces the amount of heat loss. The researchers also created innovative transition elements between absorber tube and sheath which allows virtually the entire receiver to be used for capturing solar heat, thereby also increasing the efficiency of the system. A special process based on nanotechnology applies an anti-reflection coating and a temperature-resistant absorber coating that converts solar radiation into heat round off the package of innovations.
With the new design the researchers laid the foundation for the more productive and efficient operation of solar power plants – making power generation from solar energy both sustainable and economically worthwhile.