Tese: Modeling of a two-phase thermosyphon loop with low environmental impact refrigerant applied to electronic cooling
Aluno(a) : Veronica da Rocha WeaverOrientador(a): José A. Parise
Área de Concentração: Termociências
Data: 06/10/2020
Link para tese/dissertação: http://doi.org/10.17771/PUCRio.acad.55177
Resumo: Given the constant advances in technology, electronic devices have been going through a process of miniaturization while sustaining an increase in power. This trend proves to be a challenge for thermal management since commonly electronic cooling systems are air-based, so that the low heat transfer coefficient of air limits its capacity to keep up with the thermal needs of today’s industry. In this respect, two-phase cooling has been regarded as a promising solution to provide adequate cooling for electronic devices. Two-phase thermosyphon loops combine the technology of two-phase cooling with its inherent passive nature, as the system does not require a pump to provide circulation for its working fluid, thanks to gravity and buoyancy forces. A micro-channel heat sink located right on top of the electronic device dissipates the heat generated. This makes for an energy and cost-efficient solution. Moreover, having a thermosyphon loop operating with a low GWP refrigerant such as R-1234yf results in low impact for the environment since it is an environmentally friendly refrigerant, and the system has low to none energy consumption. This work provides a detailed numerical model for the simulation of a two-phase thermosyphon loop operating under steady-state conditions. The loop comprises an evaporator (chip and micro-fin heat sink), a riser, a tube-in-tube water-cooled condenser and a downcomer. Fundamental and constitutive equations were established for each component. A finite-difference method, 1-D for the flow throughout the thermoysphon’s components and 2-D for the heat conduction in the evaporator and chip, was employed. The model was validated against experimental data for refrigerant R134a, with good agreement. Additional simulations were performed to present a performance comparison between R134a and its environmentally friendly substitute, R1234yf.