Scientists have developed a material that can generate electricity from solar heat to produce cheap solar energy on cloudy days and at night.
Innovation is an important step in generating solar heat – electricity generation in direct cost competition with fossil fuels, researchers said.
"Storage of solar energy as heat may already be cheaper than storing energy through batteries, and the next step is to reduce the cost of producing solar heat from electricity with the added benefit of greenhouse gas emissions," Kenneth Sandhage said. a professor at Purdue University in the USA.
Concentrated solar power plants convert solar energy into electricity by using mirrors or lenses to concentrate a lot of light into a small area that generates heat that transforms into molten salt.
The heat from the molten salt is then transferred to a "working" liquid, supercritical carbon dioxide that expands to spin a turbine to generate electricity.
To make solar-powered electricity cheaper, the turbine engine would need to be even more power for the same amount of heat, meaning that the engine has to run hotter.
The problem is that heat exchangers that transfer heat from the hot molten salt to the working fluid are currently manufactured from stainless steel or nickel-based alloys that become too soft at the desired higher temperatures and pressure of supercritical carbon dioxide.
Researchers designed a composite of ceramic zirconium carbide and tungsten metal for more robust heat exchangers
They produced ceramic-metal composite plates. The plates house customizable channels to accommodate heat exchange.
Mechanical tests and corrosion tests have shown that the composite material can be tailored to withstand the higher temperature supercritical carbon dioxide needed for more efficient power generation
. Economic analysis also showed that large scale manufacturing of these heat exchangers at a cost comparable to or lower than that based on stainless steel or nickel alloy.
"Ultimately, with continued development, this technology would enable widespread deployment of renewable solar energy into the grid," Sandhage said.
"This would mean a dramatic reduction in man-made carbon dioxide emissions from power generation," he said.
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