Rami Sabbah

Passive thermal management using phase change material (PCM) for EV and HEV Li- ion batteries

Researchers at the Illinois Institute of Technology (IIT, Chicago, IL) have successfully demonstrated a passive thermal management system using phase change materials (PCM) in Li-ion batteries for electric vehicle and scooter applications. Thermal characterization of Li-ion battery modules using PCM is presented and discussed. In addition, a battery pack design for plug-in hybrid vehicles (PHEV) is proposed and discussed.

Miniaturized Refrigeration System With Advanced PCM Micro Encapsulation Technology

Technology advances in microchips and miniaturized refrigeration systems require heat to be removed at a high flux. Microchannel heat exchangers have been implemented for the efficient removal of heat in these applications. However, the maximum achievable heat flux is still limited even when two-phase flow (evaporation) is used, due to the formation of vapor film along the wall of the heat exchanger. In this presentation, the principle of using a suspension of microcapsules in liquid as a heat transfer fluid to improve the performance of microchannel heat exchangers will be discussed. The microcapsules contain phase change material, which melts and solidifies at a specified range of temperatures. These microcapsules improve the fluid effective specific heat capacity and thermal conductivity due to latent heat effect and micro mixing respectively.© 2007 ASME

Natural Convection With Micro-Encapsulated Phase Change Material

This study numerically explores the effect of presence of Micro-Encapsulated Phase Change Material (MEPCM) on the heat transfer characteristics of a liquid in a rectangular cavity driven by natural convection. The Natural convection is generated by the temperature difference between two vertical walls at constant temperatures. The Phase Change Material (PCM) inside the MEPCM particles melts in the vicinity of the hot wall and solidifies near the cold wall. Unlike pure liquids, the heat transfer characteristics of MEPCM slurry cannot be simply presented in terms of corresponding dimensionless controlling parameters such as Rayleigh number. In the presence of phase change particles, the controlling parameters’ values change significantly due to the local phase change. The numerical results show significant increase in the heat transfer coefficient (up to 80%). This increase is a result of the MEPCM latent heat and the increased volumetric thermal expansion coefficient due to MEPCM volume change during melting.© 2009 ASME

Characteristics of Hydro-Dynamically and Thermally Developing Liquid Flow With Micro-Encapsulated Phase Change Material

This numerical investigation explores the hydrodynamic and thermal boundary layers characteristics of a liquid flow with Micro-Encapsulated Phase Change Material (MEPCM). Unlike pure liquids, the heat transfer characteristics of MEPCM slurry can not be simply presented in terms of corresponding dimensionless controlling parameters such as Peclet number. In the presence of phase change particles, the controlling parameters’ values change significantly along the tube length due to the phase change. As a result, the hydrodynamic and thermal boundary layers are significantly affected by the changing parameters. The numerical results reveal that the growth of the thermal boundary layer for MEPCM slurries is different than for pure liquids. The presence of MEPCM in the working fluid slows the growth of the thermal boundary layer and extends the thermal entry length. The local heat transfer coefficient strongly depends on the location of the melting zone interface.Copyright

Eexperimental Investigation of Heat Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

This experimental study investigates the effect of presence of Micro-Encapsulated Phase Change Material (MEPCM) within the working fluid on thermal performances of the cooling system. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.3mm and a length of 1,016mm is selected. 5%, 10% and 20% mass concentration MEPCM slurries with particle diameter ranging between 5–15μm were included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding heat transfer coefficients are determined for various operating conditions. Differential Scanning Calometery (DSC) test results for an iterative method for local variables calculation. The experimental results showed significant enhancement in heat transfer coefficient higher than 50% and reduction in tube wall temperature higher than 35%. The controlling parameters are identified and their effects on the heat transfer characteristics are evaluated and analyzed.Copyright

Experimental and Numerical Investigation of Heat Transfer Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

This experimental and numerical study investigates Micro-Encapsulated Phase Change Material (MEPCM) heat transfer characteristics and corresponding pressure drop. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.5mm and a length of 1,016mm is selected. A MEPCM mass concentration of 20% slurry with particle diameter ranging between 5–15μm is included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding Nusselt number are determined for various operating conditions. The experimental results are used to validate the numerical model predictions. The numerical model results show good agreement with the experimental data under various operating conditions. The controlling parameters are identified and their effects on the heat transfer characteristics of micro-channels with MEPCM slurries are evaluated.Copyright