Graphite Foam Infused with Pentaglycerine for Solid-State Thermal Energy Storage

The use of a solid-state phase change material, pentaglycerine, in thermal energy storage was investigated. The motivation for exploring a thermal energy storage system that relies on a solid-state phase transition is to eliminate phase change material leakage and sealing issues. Pentaglycerine was effectively injected into graphite foam, and this combination was studied for potential use in a thermal energy storage device. Graphite foam samples that contained pentaglycerine demonstrated a storage capacity that was close to the theoretical capacity. The graphite foam infused with pentaglycerine retained 100% of its storage capacity after 59 separate thermal cycles under various conditions, with many of those cycles contiguous. It was subjected to a 28% duty cycle of applied heat flux under active cooling conditions, and the duty cycle of the sample was not adversely affected by subcooling of the pentaglycerine. The one-dimensional model developed for this study assumed a homogeneous mixture of pentaglycerine and foam which were in local thermal equilibrium with each other. The numerical results reasonably represented the effects of phase change as reflected by the temperature histories for several locations within a graphite foam-pentaglycerine sample. The current study showed that the graphite foam-pentaglycerine combination has potential for use in thermal energy storage devices.