New ceramic composite material makes solar energy production cheaper: study

Mechanical tests and corrosion tests have shown that the composite material can be adapted to withstand the higher temperature of the new heat exchangers. (Image Source: Purdue University)

Scientists have developed a material that can be used to harvest electricity from the Sun's heat, paving the way for cheaper solar power generation on cloudy days and at night. Innovation is an important step for solar heat generation to compete directly with fossil fuels, the researchers said.

"Storing solar energy in the form of heat can already cost less than energy through batteries. The next step will be to reduce the cost of producing electricity from the Sun's heat while reducing greenhouse gas emissions, "said Kenneth Sandhage, a professor at Purdue University in the United States. Concentrating solar power plants convert solar energy into electricity by using mirrors or lenses to focus a large amount of light onto a small area, generating heat that is transferred to a molten salt.

The heat from the molten salt is then transferred to a working fluid, supercritical carbon dioxide, which expands and operates to spin a turbine to generate electricity. To make solar electricity cheaper, the turbine engine would have to produce even more electricity for the same amount of heat, which means the engine has to run hotter. The problem is that the heat exchangers, which transfer heat from the hot molten salt to the working fluid, are currently made of stainless steel or nickel-based alloys that become too flexible at the desired higher temperatures and high pressure. supercritical carbon dioxide.

The researchers designed a ceramic zirconium carbide and metallic tungsten composite for more robust heat exchangers. They created ceramic-metal composite plates. The plates host customizable channels to accommodate the heat exchange.
Mechanical tests and corrosion tests have shown that the composite material can be adapted to withstand the high pressure and high temperature supercritical carbon dioxide required to produce electricity more efficiently than current heat exchangers.

An economic analysis also showed that large scale manufacturing of these heat exchangers could be performed at a cost comparable to or lower than that of stainless steel or nickel alloy heat exchangers. "Ultimately, with continued development, this technology would enable large-scale penetration of renewable solar energy into the grid," said Sandhage. "This would result in a dramatic reduction in human-induced carbon dioxide emissions resulting from the generation of electricity," he said.

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