Mighty Mite

This article presents an overview of a turbine that uses supercritical carbon dioxide (CO2) to deliver great power. At around 73 atmospheres and roughly room temperature, CO2 makes a strange transition from a gas to a state known as a supercritical fluid. A supercritical fluid is dense, like a liquid, but it expands to fill a volume the way a gas does. These properties make supercritical CO2 an incredibly tantalizing working fluid for Brayton cycle gas turbines. Such gas turbine systems promise an increased thermal-to-electric conversion efficiency of 50% over conventional gas turbines. The system is also very small and simple, meaning that capital costs should be relatively low. The plant uses standard materials like chrome-based steel alloys, stainless steels, or nickel-based alloys at high temperatures (up to 800°C). It can also be used with all heat sources, opening up a wide array of previously unavailable markets for power production. For these reasons, the technology is quite promising.