Experimental investigation of multiwall carbon nanotube/paraffin based heat sink for electronic device thermal management

This paper presents experimental investigation for the effects of a phase change material (PCM) and a nano/ phase change material (nano-PCM) on the thermal performance of an electronic chipset. A thermal storage system using Paraffin wax as a PCM is integrated with a heat sink. Additionally, the PCM is modified as nano-PCM by mixing it with multiwall carbon nanotubes (MWCNTs). The effects of various quantities of the PCM, concentrations of the MWCNTs in the PCM, and different power levels on three different modules of heat sinks (without PCM, filled with PCM, and filled with nano-PCM) are studied in passive and active operating modes. Experiments are also performed when the heat flux is applied intermittently, which commonly encountered in the thermal management of portable electronic devices. The phase front propagation is captured and analyzed by an image processing technique. It is found that the PCM can significantly increase the usage time of the system and the nano-PCM as compared to the PCM can extend this time under passive cooling condition. Under active cooling condition, the usage of PCM and nano-PCM may increase the steady-state temperature; however, it reduces the operating temperature of the chipset at the beginning period of the operating time. The nano-PCM module can enhance thermal management of the system by reducing the cooling time up to 6% as compared to the PCM. Under intermittent heating, using more on-and-off cycles lead to decreasing the chipset peak temperature. Using PCM and nano-PCM increases the operating time and reduces the peak temperature of the chipset under intermittent use.