Fundamental limits of dynamic phase change materials

Abstract

To accommodate societal electrification and decarbonization, renewable energy resources continue to expand their share of the global energy market. The intermittency of renewable energy technologies as well as the high power density of modern electrified platforms necessitates the need for both efficient thermal management and high-density thermal storage. Phase change materials are a promising passive thermal energy storage solution. However, difficulties with efficient system implementation stemming from the inherent melt pool formation hinder their potential. We develop an innovative strategy, termed dynamic phase change material “dynPCM,” to address this thermal transport issue by ensuring a constant, thin, melt layer. We analyze the fundamental limits of dynPCMs, characterize the peak achievable heat flux and energy/power densities, estimate the power consumption of dynPCM systems, and investigate the fundamental physics which govern dynPCM behavior. We show that dynPCM can eliminate the classical trade-off seen between energy density and power density and achieve ultrahigh heat fluxes, ∼105 W/cm2, with heat flux-to-required power ratios as high as ∼107. We also demonstrate achievable power densities as high as ∼100 W/cm3 at energy densities as high as ∼10 kJ/cm3. Throughout this work, we develop a methodology to evaluate the operating limits, enabling adaptation of the dynPCM system concept to a variety of applications and industries.