Experimental and numerical studies on the cooling of mobile device

• Main Author: Setoh, Guojing.
• Other Authors: Tan Fock Lai
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Manufacturing::Product engineering
• Online Access: http://hdl.handle.net/10356/17077
• Institution: Nanyang Technological University

With the advancement in technology, consumers can expect mobile devices (cellular phones, laptop computers, PDA, etc.) to be packed with more complex components and features to satisfy consumer demand. On the other hand, the packaging of the mobile devices is made smaller, reducing the external surface area available for heat dissipation. Enhanced and added power consuming features will only worsen the thermal management. The end result will be an increase in power density despite an increased usage of power management in both hardware and software. Effective cooling strategies are needed to prevent over heating of the components and also to suit the comfort of the user. In this project, an experimental study is conducted on the feasibility of cooling mobile devices using phase change material. The high heat of fusion of phase change material will be tested on the capability of storing latent heat dissipated from the heat source. Aluminum heat sinks are fabricated and filled with phase change material of n-eicosane. The usage of internal fins was investigated for effects on the phase change material. Three different heat sinks were fabricated. The first one is without fins, second one with three fins and the last one with six fins. Three different power levels of 3W, 4W and 5W were experimentally tested in this study. The discharging effect of the phase change material was tested in the experiments. This is to analyze the effectiveness of phase change material when it is fully melted. In addition, transient charging and discharging of the mobile device in three different scenarios were studied; light user, moderate user and heavy user. Thermocouples and thermal imager were used to capture the data for analysis. Results have shown that increased power will increase the melting rate. With an increase of internal fins, the maximum temperature of the heat sinks and plastic casing can be maintained at a lower temperature. The time taken for complete solidifying of liquid PCM is much longer as compared to complete melting of solid PCM. The use of PCM is only effective in making intermittent calls but not long duration calls.