Nanoparticle Enhanced Crystallization of Sorbitol PCMs for Latent Heat and Temperature Control

摘要

Thermal management plays an important role in maintaining reliable functionality in electronic systems. As electronic packaging scales for increased power density, the need for cost effective heat removal becomes vital to electronic system design. Conventional systems, such as heat pipes, fans, and liquid cooling methods, require significant energy input, resulting in reduction of total system efficiencies. Phase change materials (PCMs) offer a safe and efficient passive thermal management approach that can supplement traditional cooling methods such as air and liquid cooling. PCMs can help absorb thermal energy during temperature spikes and with the addition of current cooling systems, can aid in cooling applications to increase the reliability of electronic devices. Within the broad PCM characterization, sugar alcohols have displayed promising thermal properties such as high specific latent heat (W/g), which is a useful metric for determining maximum thermal heat absorption, and the appropriate phase transition temperatures for electronic systems. These properties have been shown to be altered with nanoparticle inclusion, leading to more effective and efficient nanocomposites for thermal management.This study examines the impact of gold and iron oxide nanoparticles on the latent heat, melting temperature, and crystalline properties of D-Sorbitol (promising sugar alcohol). Particle size, concentration, and spatial density are discussed for their effects in changing the properties of the PCM. The particle induced augmentation was evaluated using various crystallographic, mechanical, fluid, and thermal characterization techniques, to illustrate the mechanism of PCM enhancement. The structure of Sorbitol is polycrystalline, but it can be shown that nanoparticle inclusion introduces controllable crystalline ordering. This work encompasses what trends can be seen with the change in certain properties within sorbitol using nanoparticles. The increase in latent heat is dependent on the preferred crystalline structure of the nanocomposite based on the changes introduced by the nanoparticles. Furthermore, liquid-to-solid formation kinetics were also observed through rheology and shear stress induced crystallization. The focus of this paper will be on the crystalline changes present in the new nanocomposites and the relationship between structure and thermal characteristics as controlled by varying nanoparticle properties.