CERAMIC COMPOSITE – SCI & TECH

News: Efficient passive radiative cooling materials developed

 

What's in the news?

       Researchers conceived a composite of ceramic zirconium carbide and tungsten, to create robust heat exchangers for conversion of solar heat to electricity.

       By creating plates of the ceramic-metal composite, they were able to get better performance at higher temperatures.

 

Key takeaways:

  1. Scientists have developed a material that can be used to harvest electricity from the Sun’s heat.
  2. This innovation paves the way for generating cheaper solar power on cloudy days and at night time.
  3. The innovation is an important step for putting solar heat-to-electricity generation in direct cost competition with fossil fuels

 

How does it work?

       Concentrated solar power plants convert solar energy into electricity by using mirrors or lenses to concentrate a lot of light onto a small area, which generates heat that is transferred to a molten salt.

       Heat from the molten salt is then transferred to a “working” fluid, supercritical carbon dioxide, that expands and works to spin a turbine for generating electricity.

       To make solar-powered electricity cheaper, the turbine engine would need to generate even more electricity for the same amount of heat, which means the engine needs to run hotter.

       The problem is that 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 get too soft at the desired higher temperatures and at the elevated pressure of supercritical carbon dioxide.

       Researchers conceived a composite of ceramic zirconium carbide and the metal tungsten for more robust heat exchangers.

       They created plates of the ceramic-metal composite.

       The plates host customisable channels for tailoring the exchange of heat.

       Mechanical tests and corrosion tests showed that the composite material could be tailored to successfully withstand the higher temperature, high-pressure supercritical carbon dioxide needed for generating electricity more efficiently than today’s heat exchangers.