Enhancing heat rejection from electronic devices with a supercritical carbon dioxide minichannel heat exchanger

The need for high heat flux dissipation in computing centers due to compactness of electronic components has created unforeseen challenges. Due to its large heat transfer coefficients, numerous studies propose the use of phase-change cooling. However, because of the limited operational temperatures allowed within microprocessors, closed cycles often require the employment of refrigerants, which generally present high GWP (Global Warming Potential)/ODP (Ozone Depletion Potential). Here, a s-CO2 (supercritical carbon dioxide) cooling system for thermal management of compact, multi-electronic circuits is investigated. This minichannel heat exchanger cooling unit takes advantage of variations in s-CO2's properties near the critical point for achieving large thermal conductance and reduced compressing power. It is shown that the cooling unit operating pressure could be controlled to provide maximum cooling rates depending on the thermal load of the electronic circuit. The cooling unit is shown to be compact and to present high heat transfer coefficients (similar to 10(4) Wm(-2)K(-1)), allowing the electronic component to operate with significant heat transfer rates, and with minimal environmental footprint given the low GWP/ODP of CO2. (C) 2019 Elsevier Ltd and IIR. All rights reserved.