We have successfully used techniques found in computational chemistry to identify a series of compounds for use as nontoxic heat transfer fluids for habitat two-phase thermal control systems. Our approach allows us to screen compounds, based on their molecular structure, where no thermodynamic data exists. Once compounds that have the desired properties are identified, their properties can be measured.
The key problem in developing the most efficient and versatile two-phase pumped fluid system is the selection of the appropriate working fluid. Although many fluids are good candidates in terms of their thermodynamic properties, they cannot be used inside pressurized, habitat volumes due to toxicity, flammability, and thermal stability concerns.
We used our computational chemistry approach based on pattern recognition techniques to correlate a molecules thermodynamic and chemical properties with its molecular structure, we have identified several perfluorocarbons that meet the NASA design requirements.