Thermodynamic Property Measurements of Supercritical Fluid Mixtures for Energy Storage Applications
Researcher: Mitchell Ishmael
Principal Investigator: Professor Jefferson Tester
Our group is investigating energy storage mechanisms in supercritical fluid mixtures to improve the efficiency and cost effectiveness of intermittent renewable energy sources. We want to engineer the desirable thermophysical properties of supercritical fluids (seen in the figure) to increase their energy storage potential. To evaluate candidate mixtures, we have built a supercritical fluid calorimeter to make constant pressure heat capacity measurements. We have not limited our storage material exclusively to fluid mixtures and are currently making preliminary measurements to evaluate the potential of nanoparticle-supercritical fluid suspensions.
Figure 2: Fluids in their near critical region show heat capacities several times higher than at ideal gas or subcooled liquid states. The figure above on the left shows this enhancement in the isobaric heat capacity of carbon dioxide along different isotherms.
Figure 1: The supercritical fluid flow calorimeter allows us to measure isobaric heat capacity of pure fluids and mixtures. It is composed of the following major elements: (A) data acquisition system with a GUI, (B) DC power supply for heating element, (C) outlet cooling bath, (D) vacuum pump, (E) sand bath with the vacuum chamber.