Experimental Investigation of Thermal Management of Tablet Computers Using Phase Change Materials (PCMs)

Abstract

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 °C; PT-37 – 36.3 °C) but different latent heats of fusion (n-eicosane – 236 kJ/kg; PT-37 – 206 kJ/kg). Two encapsulations with different sizes (6″ × 2.6″, 7″ × 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 °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.

Passive Thermal Management of Tablet PCs Using Phase Change Materials: Intermittent Operation

“…Two PCMs were selected: n-eicosane (99% pure, AS number-A13853, purchased from Alfa Aesar, Ward Hill, MA, USA) and PT-37 (a commercial PCM manufactured by PureTemp, Plymounth, MN, USA) with melting temperatures of 35.6 • C and 36.3 • C, respectively. Both PCMs have good chemical stability under melting-solidification cycles [21], a requirement for long-term use. It is also known that the corrosion of aluminized laminate film, the prospective encapsulation material used in the current research, was negligible with these PCMs [22].…”

“…Both PCMs have good chemical stability under melting-solidification cycles [21], a requirement for long-term use. It is also known that the corrosion of aluminized laminate film, the prospective encapsulation material used in the current research, was negligible with these PCMs [22]. Table 1 presents the thermophysical properties of n-eicosane and PT-37.…”

Experimental Investigation of Thin PCM Packages and Thermal Spreader for Thermal Management of Portable Electronic Devices

“…An interesting approach that could lead to a reduction of peak temperatures and therefore increased time of operation of electronic components is based on phase change materials (PCMs) integration into the design of tablets [10][11][12]. Typically, portable electronic devices operate in transient cycles, meaning that heat is produced during short periods of demanding use, followed by longer periods of idling or less demanding use.…”

“…However, a small number of investigations with the aim of using PCM as part of the thermal management system of thin electronic devices (overall thickness in the range of 15 mm or smaller) have been published [10][11][12][25][26][27][28][29][30], and those are of great interest to the field of study and this work specifically. Numerical investigation on the thermal management of a modern computer tablet including thin PCM layers (0.5 mm) was performed by Sponagle and Groulx [11].…”

“…Ahmed et al [10,12] presented the first experimental study testing PCM temperature management using real tablet PC components. PCM encapsulated in aluminized laminated film with a thickness of only 2 mm was used.…”