U.S. Department of Energy - Energy Efficiency and Renewable Energy
Direct Supercritical Carbon Dioxide Receiver Development
The demonstration of the 250 kWth receiver experimental loop will occur at high pressure, requiring a source of compressed s-CO2. Heat absorbed in the receiver will serve to pre-heat the incoming CO2 to temperature, and the remaining portion will be rejected in an air-cooled heat exchanger. Image from NREL
The National Renewable Energy Laboratory (NREL), under the National Laboratory R&D competitive funding opportunity, is working to develop, characterize, and experimentally demonstrate a novel high-temperature receiver technology using supercritical carbon dioxide (s-CO2) directly as the heat transfer fluid (HTF). A high-temperature receiver that is compatible with s-CO2 enables a significant increase in power cycle efficiency and reduces solar-field size, thereby decreasing the installed cost of concentrating solar power (CSP) systems.
The team will expand the scope of its "nested-tube" receiver design configured for a reheat s-CO2 power cycle to include other types of s-CO2 receivers and power cycle configurations. The approach will use a closed receiver configuration to directly heat s-CO2 in the receiver and deliver it to the power cycle without intermediate heat exchange. NREL will analyze three direct receiver configurations and select a single concept for detailed prototype design and construction for on-sun testing. The criteria for success will be a receiver that can achieve 90% thermal efficiency and produce s-CO2 above 650°C. The team will also demonstrate a receiver that can withstand 10,000 thermal cycles before failure and has an expected commercial cost of less than $150/kWth.
The s-CO2 system uses no water, which is significant given that CSP plants are typically located in hot, dry climates where water is scarce. The direct s-CO2 receiver has numerous potential advantages over indirect molten-salt receivers. Additionally, heating s-CO2 directly delivers benefits that are most pronounced with smaller systems that have a few hours of thermal storage, including the ability to place the power cycle in the receiver to minimize the length and cost of high-pressure piping.
Publications, Patents, and Awards
At this time, this project does not have published articles, patents, or awards.
Learn about other DOE competitive awards for concentrating solar power research that are in progress.