A new PCM composite with microencapsulated phase change material slurry saturated in metal foam for passive thermal management

Organic/inorganic phase change materials (PCMs) are used in a variety of thermal applications such as thermal control, thermal management and energy storage systems because most of PCMs have the merits of high latent-heat density and selectable phase-change point. However, they suffer from disadvantages of low thermal conductivity, super cooling, volume expansion and corrosion issue. To address these problems, this article reported a thermally-enhanced PCM composite for passive thermal management with microencapsulated phase change material slurry (MPCMS) saturated in metal foam. Microencapsulation technology for PCM avoided the super cooling, volume expansion during phase change, and segregated the core PCM from environment to solve the corrosion issue. The addition of metal foam was aimed to further enhance the heat transfer rate. The experimental system to evaluate the flow and thermal performances of the MPCMS/foam composite was built. The case of pristine MPCMS was employed as the control group. The thermal characteristics of MPCMS and MPCMS/foam modules in terms of surface/internal temperatures were extracted and compared. The effects of natural convection of slurry and foam geometries on the surface temperature of MPCMS/foam were investigated. Experiment results showed that significant temperature reduction in the heated surface was achieved by MPCMS/foam composite at the penalty of shrinking the thermal management time since metal foam enhanced heat transfer rate and reduced the latent heat density. The natural convection of slurry exerted important role in heat transfer of MPCMS, but was almost suppressed in the compact pore structure in MPCMS/foam composite. Moreover, lower porosity MPCMS/foam composite had lower surface temperature than higher porosity composite.