Fabrication and Thermal Characterization of the Modularized Thermal Storage Unit

Phase change materials (PCMs), due to their extraordinary latent heat storage characteristic, have been widely investigated in the thermal management of electronic devices. However, the current PCM-based heat sinks generally suffer a long heat dissipation time after heat absorption. To address this issue, the modularized thermal storage unit (MTSU) was proposed in this paper. The online charging and offline discharging working modes of the MTSU allow it to cool the intermittent electronic devices with a high duty cycle. In this paper, the MTSU samples were fabricated with paraffin wax as latent heat storage core unit and polymer encapsulation shell. The specific latent heat storage and morphology of the MTSU samples were studied. Afterward, the thermal storage performance of each individual MTSU sample was specially characterized with the sample subjected to the constant heat flux. The MTSU samples showed desirable performance on encapsulating the PCMs and stabilizing the heat source temperature. The safe operation time of the heat source was prolonged by 181% with 16 g of PCM in the vacuum environment. Furthermore, the performance of the MTSU samples on cooling of the electronic devices with a relatively high duty cycle was investigated. The results show that owing to the modularization and replaceability of the samples, the ON/OFF working time ratio of the heat source was greatly enlarged. When cooled by the MTSU sample with 11.42 g of paraffin, the heat source could work with an ON/OFF time ratio up to 6.7 at 4 W and 14.9 at 3 W.