EXPERIMENTAL INVESTIGATION OF THERMAL MANAGEMENT OF TABLET COMPUTERS USING PHASE CHANGE MATERIALS (PCMs)

This paper presents a study of thermal management of tablet computers (tablet PCs) using phase change materials (PCMs) encapsulated in aluminized laminated film under continuous operation. The experimental setup consists of original tablet PC parts and a simplified dummy printed circuit board (PCB) with a thermal response similar to the original PCB. Two PCMs were used in the experiments, n-eicosane and PT-37 (a commercial PCM from PureTemp). These PCMs have similar melting temperatures (n-eicosane - 35.6 degrees C; PT-37 - 36.3 degrees C) but different latent heats of fusion (n-eicosane 236 kJ/kg; PT-37 - 206 kJ/kg). Two encapsulations with different sizes (6 '' x 2.6 '', 7 '' x 1.5 '') but the same thickness (0.0792 '' (2 mm)) were used in this study. The effects of inclination and power input level on the thermal behavior of the tablet were investigated. Experiments showed that PCM encapsulated in laminate film led to lower back cover temperature for constant heat flux applications. As much as a 20 degrees C temperature reduction of the back cover hotspot was achieved with encapsulated PCM. It was also observed that better thermal behavior was achieved both by the melting of PCMs and heat spreading through the laminate film. It was found that the rate of PCM melting is directly related to the power input. No significant effect on PCM melting and temperature history was observed in relation to the system inclination.