Session: 10-01 Interactive Presentations

Paper Number: 100285

100285 - Varied Phase Change Material Properties for Increased Melt Front Velocity and Heat Transfer Efficiency 

            Phase change materials (PCMs) offer the potential to add a secondary passive cooling mechanism to existing thermal management solutions to help alleviate temperature and loading spikes in electronic devices. These materials are able to absorb a large amount of energy during their phase transition from solid to liquid and maintain an isothermal temperature at the melt front. This can help to store energy during high load cycles that cannot be managed by the primary thermal management solution and can prevent damaging temperature spikes in systems. Many eligible PCMs have low thermal conductivity, preventing the materials from adequately moving energy through the PCM and away from the heat source. The static nature of material properties also makes it difficult to identify an ideal PCM for each specific thermal design. Previous literature has demonstrated the ability to augment PCM properties with the use of nanoparticles, especially for increasing bulk material thermal conductivity. Nanoparticle inclusions also alter other key properties such as melting temperature, latent heat, and specific heat of the PCM. The ability of the PCM to work effectively as a passive cooling device can be observed as a function of the melt front velocity. Poor conducting PCMs will have a slow melt front, preventing utilization of all the PCM in a proper time frame. By adding nanoparticles, the melt front velocity can be increased and the PCM can be more effectively used. Heat transfer occurs in two stages within the PCM. Early in the melting process, conduction dominates the heat transfer. Once a large enough liquid front is developed, natural convection can begin to form based on the PCM’s orientation with respect to gravity. Increasing thermal conductivity is important in both stages. The melt front is tracked using an infrared camera to map the temperature of the PCM with embedded thermocouples as reference points. Changes in material properties will be used to understand the impact of nanoparticle inclusion on the melt front velocity. Augmenting the bulk properties of a composite material with nanoparticles will lead optimization opportunities for fine tuning material benefits for specific thermal requirements. By further understanding the ability of nanoparticle inclusion to impact the melt front propagation, PCMs can be enhanced for use as secondary passive cooling devices. In this study sorbitol and paraffin are used as the base PCMs. Various carbon-based nanoparticles including multiwalled carbon nanotubes, graphene oxide, and graphene nanoparticles are used to assess the change in material properties that can be induced in these systems and their impacts on the melt front propagation.

Presenting Author: Joshua Kasitz University of Arkansas