Isotherm, Inc.

Next Generation Power Plants: Supercritical Carbon Dioxide


When Carbon Dioxide (CO2) operates above its critical point, it is called Supercritical Carbon Dioxide (sCO2) where there is no distinction between liquid and gas phase. In this phase CO2 undergoes a continuous, non-isothermal transition from “gas-like” to “liquid-like” properties resulting in significant spikes in specific heat and other thermophysical properties that can enhance heat transfer.

To take advantage of these qualities, active research is underway under the auspices of the Department of Energy (DOE) to develop a prototype advanced sCO2 Brayton cycle power plant. The source of heat could be solar, geothermal, nuclear, and/or clean fossil fuels.

A fundamental advantage of the sCO2-Brayton combo is that it results in almost double thermal efficiency as compared to a conventional Rankine cycle steam plant which, therefore, leads to smaller components and reduced freshwater consumption. Currently water consumption for power generation accounts for 45% of U.S. fresh water supply.

The major challenge to the industry is the development of materials that would be suitable for high temperature/pressure and at the same time reliable and less cost prohibitive. This leads us to a challenge to develop heat exchangers with high heat flux attributes that are compact and less expensive. Besides the material and construction aspects, another important area is the development of reliable design tools that are based on experimental, empirical, and theoretical data base.

Isotherm designed and fabricated an Ice Slurry Heat Exchanger System for a 10-Megawatt prototype power plant. The idea is to use Ice Slurry as a sink instead of air or water as used in conventional power plants. Ice Slurry operates at lower temperature than air- and water-cooled condenser with a latent heat component which results in higher thermal efficiency.

Isotherm MaximIce Dynamic Ice Slurry System