Guilherme B. Ribeiro

Bio: Guilherme B. Ribeiro is an academic researcher from Universidade Federal de Santa Catarina. The author has contributed to research in topics: Heat exchanger & Refrigeration. The author has an hindex of 9, co-authored 33 publications receiving 241 citations.

A State-of-the-Art Review of Compact Vapor Compression Refrigeration Systems and Their Applications

Abstract: We present a critical review of the literature on the fundamentals, design, and application aspects of compact and miniature mechanical vapor compression refrigeration systems. Examples of such systems are those envisaged for electronics and personal cooling. In comparison to other refrigeration technologies (e.g., solid-state), vapor compression enables the attainment of low evaporating temperatures while maintaining a large cooling capacity per unit power input to the system. Over the past decade, there have been a significant number of studies devoted to the miniaturization of system components, with the most critical being the compressor. When compared with competing cooling technologies, such as flow boiling in microchannels, jet impingement, and spray cooling, refrigeration is the only one capable of lowering the junction temperature to values below the ambient temperature. The combination of vapor compression refrigeration with the aforementioned technologies is also possible, necessary, and benefi...

Mini-channel evaporator/heat pipe assembly for a chip cooling vapor compression refrigeration system

Abstract: We investigate a novel evaporator design for a small-scale refrigeration system whose function is to assist the existing heat pipe technology currently used in chip cooling of portable computers A heat transfer model for the evaporator/heat pipe assembly was devised specifically for sizing the evaporator in order to keep the chip surface temperature below a certain value A prototype was tested with R-600a at saturation temperatures of 45 and 55 °C, mass flow rates between 05 and 15 kg h −1 and heat transfer rates between 30 and 60 W The experimental results demonstrated that the average refrigerant-side heat transfer coefficient is more sensitive to a change in the refrigerant mass flux than to changes in the saturation temperature and heat transfer rate The agreement between the calculated heat transfer coefficient and the data was within ±10% for the conditions evaluated

Nanoengineered materials for liquid–vapour phase-change heat transfer

Abstract: Liquid–vapour phase change is a useful and efficient process to transfer energy in nature, as well as in numerous domestic and industrial applications. Relatively recent advances in altering surface chemistry, and in the formation of micro- and nanoscale features on surfaces, have led to exciting improvements in liquid–vapour phase-change performance and better understanding of the underlying science. In this Review, we present an overview of the surface, thermal and material science to illustrate how new materials and designs can improve boiling and condensation. There are many parallels between boiling and condensation, such as nucleation of a phase and its departure from a surface; however, the particular set of challenges associated with each phenomenon results in different material designs used in different manners. We also discuss alternative techniques, such as introducing heterogeneous surface chemistry or direct real-time manipulation of the phase-change process, which can offer further control of heat-transfer processes. Finally, long-term robustness is essential to ensure reliability and feasibility but remains a key challenge. Recent works in boiling and condensation have achieved unprecedented performance and revealed new mechanistic insights that will aid in material design. In this Review, we focus on nanoengineered materials, with emphasis on further improving the heat-transfer performance and long-term robustness.

Review of micro- and mini-channel heat sinks and heat exchangers for single phase fluids

Abstract: Depleting energy resources have become the driving force for their conservation. Increasing the system efficiencies is one method by which sustainability of energy may be ensured, for which miniaturization has successfully provided solutions. Miniature heat exchangers, owing to their high thermal performance, have the potential to provide energy efficient systems. In addition, their characteristics of compactness, small size and lesser weight have attracted widespread applications. Various works on micro- and minichannel heat exchangers as heat sinks and heat exchangers have been reviewed in this paper. Currently employed fabrication techniques and different applications have been summarized. An overview of the single-phase thermo-hydraulic studies in micro- and minichannel heat sinks has been presented. Literatures related co-current, counter-current and cross-current micro- and minichannel heat exchangers have been discussed. Finally, the persisting lacunae of this technology drawn from the review have been pointed out.

A chip scale electrocaloric effect based cooling device

Abstract: The recent finding of large electrocaloric effect in several ferroelectric polymers creates unique opportunity for developing compact size solid state cooling cycles beyond the traditional mechanical vapor compression cycles. Here, we show that, by employing regeneration process with solid state regenerators, a chip scale Electrocaloric Oscillatory Refrigeration (ECOR) can be realized. A prototype ECOR is fabricated and characterized. More than 6 K temperature span is obtained near room temperature between the hot and cold sides of a 2 cm long device. Finite volume simulation validates the test results and shows the potential high performance of the ECOR.