In recent years, the Department of Energy has backed lots of projects focused on lowering the cost of solar power. Another project, at the Wisconsin Energy Institute, recently received a $2.6 million grant from the agency to design a power conversion unit for concentrating-solar-power (CSP) plants.
CSP power plants generate solar energy by reflecting and concentrating sunlight onto small solar collectors. The solar energy is transferred into a fluid, usually supercritical steam or synthetic oil, which is then used as a heat source for an electrical power generator.
As outlined in the research proposal, the team will design two advanced power cycle units that transfer thermal energy into a supercritical carbon-dioxide (sCO2) fluid. According to Department of Energy research, this sCO2 fluid exhibits a higher thermal stability than the supercritical steam used in CSP power plants, increasing the efficiency of the thermal-to-electric energy conversion.
Because sCO2 has the density of a liquid in a gaseous state, the power consumed by operating the electric generators is significantly reduced. Although it is targeting solar energy, the power cycle will also be compatible with nuclear and geothermal energy, as well as fossil fuels. The research will become part of the Energy Department’s SunShot Initiative, which aims to make solar energy cost-competitive with other forms of energy.
The research team is also planning to develop a new regenerator unit for transferring heat into the electrical generators. While specific details about the design have not yet been released, the new regenerator is being designed to have better capabilities for internal heat transfer and energy storage than the recuperators currently used in CSP power plants.
The research team is also engineering a pre-cooling system that can release heat into the atmosphere at lower temperatures than current CSP systems. Using dry cooling capabilities, the system will be capable of reducing waste energy and limiting the amount of water used in the cooling process.
More information about the research proposal has not yet been released by the Wisconsin Institute or the Energy Department. The research team is headed by University of Wisconsin-Madison professor Mark Anderson. The proposal has not yet been added to the the official list of SunShot-funded projects.
Anderson and UW-Madison professor Greg Nellis will collaborate with members of the Colorado School of Mines, Sandia National Laboratories, the National Renewable Energy Laboratory, heat-transfer company CompRex, and chemical-process equipment company Flowserve. The team will test the new power units at a prototype facility in Albuquerque, New Mexico.