Design and Assessment of an Innovative Thermal Management System for Electronic Cooling Using PCMs

A Master of Science thesis in Mechanical Engineering by Yahya Abdulrahman Sheikh Mohammed entitled, “Design and Assessment of an Innovative Thermal Management System for Electronic Cooling Using PCMs”, submitted in July 2020. Thesis advisor is Mohamed Gadalla. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form).

Abstract

Thermal management of electronics is an important issue since the reliability of electronic components is greatly affected by the operating temperature. Electronics, such as laptops, are becoming more likely to overheat as their dimensions become smaller. Overheating an electronic device can cause problems such as a sudden shutdown, system freezing, and most importantly, it will affect its lifetime. To overcome this problem, a small vapor compression refrigeration (VCR) system integrated with Phase change materials (PCMs) is proposed. PCMs could be effective when electronic cooling systems such as heat sinks are considered. However, bio-based PCMs have poor thermal conductivity and therefore suffer from poor heat transfer characteristics. The diffusion of certain additives within the PCM has proven successful in the enhancement of heat transfer during the cooling process. Graphene Nanoplatelets (GNPs) presents itself as one such additive. This work experimentally investigates the cooling performance of the heat sink when GnPs and Graphite with various surfactants such as Sodium Dodecyl Sulfate (SDS), Sodium Dodecylbenzene Sulfonate (SDBS) and Sodium Stearoyl Lactylate (SSL) are added to the bio-based PCM. SSL NanoPCM provided a 345-sec delay compared to the Pure PCM, and the response time of PCM was improved be 51% when it was mixed with GnPs at 5% mass fraction. SDS surfactant indicated the highest increase in thermal conductivity when compared to others as it reported the highest increase of 368% when compared with the thermal conductivity of PurePCM. The main objective of this work is to design a new active cooling system to cope with increasing demand for powerful and high-performance electronics. The system is made of a compressor, an expansion device, a condenser, an evaporator, a fan, and a cold storage. The system is designed for laptop cooling with a cooling capacity of 100W and the dimension of the system is 38 × 30 × 15 cm. A comprehensive thermodynamic analysis was performed. While modelling the performance of the system, it is found that R134a has the best performance among the others. When the laptop cooler was used, the maximum temperature of the central processing unit (CPU) was found to be 67 °C, while it was 78 °C without using the cooler. Noticeably, using the cooler helped in reducing the temperature of CPU by 11 degrees (14.1%).