Modeling and analysis of Phase Change Materials for efficient thermal management

Abstract

Direct placement of Phase Change Materials (PCMs) on the chip has been recently explored as a passive temperature management solution. PCMs provide the ability to store large amounts of heat at a close-to-constant temperature during the phase change (solid to liquid and vice versa). This latent heat capacity can be used to provide higher performance while reducing hot spots. Detailed modeling of the phase change behavior is essential for the design and evaluation of systems with PCM. This paper proposes an accurate phase change model that is integrated into the commonly used thermal simulation tool, HotSpot. It also provides validation of the proposed model by carrying out computational fluid dynamics (CFD) simulations using COMSOL Multiphysics <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> . This paper also explores the impact of PCM properties on the thermal profile of a processor, and demonstrates that PCM material choices can affect peak temperatures by up to 20.1°C. Experimental results show that dynamic policy decisions change dramatically when using the proposed detailed phase change model, as prior simpler PCM models can substantially over/under-estimate temperature and PCM melting duration. The proposed model helps design more effective dynamic management policies and enables realistic evaluation of systems with PCM.