Electronics cooling

About: Electronics cooling is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 17608 citations.

Issues In The Thermal Management Of Outdoor Telecommunications Cabinets/enclosures

Abstract: In many telecommunications applications, switchinglsignal processing equipment is continuously increasing in capabilities. and more importantly, heat dissipation. The problem starts at the boardsub-component level and grows to the system level. The equipment often must be housed in enclosures that more often than not will be placed outdoors. The housed equipment generates heat that must dissipated while keeping the air temperature inside the cabinets within prescribed limits for optimum performance. Thermal management of all telecommunications systems, thus, becomes of primary importance for any telecommunications operation. This paper will describe the thermal analysis of outdoor enclosures (from small to large sizes) that house telecommunications equipment Furthermore, the different approaches open to engneers for the design and development of thermal management of these systems are presented. Both passive and active means of thermal management are included in the discussion as well as typical auxiliary devices such as air-to-air heat exchangers, air conditioners, phase-change materials, heat pipes, thermosiphons, etc.

Two-phase liquid cooling system for electronics, part 3: Ultra-compact liquid-cooled condenser

Abstract: An experimental study to investigate the thermal performance of a two-phase thermosyphon for electronics cooling is presented in this article. In this study, the thermosyphon evaporator was connected via a riser and a downcomer to an ultra-compact condenser operating as a refrigerant-to-refrigerant counter flow heat exchanger. The secondary side of the condenser evaporated R134a from a “bus line” to condense the working fluid in the thermosyphon. Experiments were carried out for filling ratios ranging from 60% to 76%, heat loads from 102 W to 1841 W, secondary side mass flow rates from 40 kg/h to 120 kg/h, inlet subcoolings from about 0 K to 5 K, and saturation pressures from 600 kPa to 730 kPa. Robust thermal performance was observed for the entire range of operating test conditions. In particular, at the optimum filling ratio of 65%, secondary side mass flow rate of 80 kg/h, inlet subcooling close to 0 K and saturation pressure of 600 kPa, the mean temperature difference from the evaporator to inlet coolant was only 9.4 K. Experimental results demonstrated an increase of 14X in heat density dissipation, 19X increase in energy efficiency and a virtually noiseless system compared to the air-cooled thermosyphon discussed in Part 2.

Thermally enhanced pressure regulation of electronics cooling systems

Abstract: A two-phase cooling system operated at atmospheric pressure. A reservoir containing cooling fluid has a stack that is vented to the atmosphere. The stack is shaped to allow condensation of substantially all of the cooling fluid in vapor form entering the stack. Condensation may be enhanced by cooling the stack, such as with flowing air along the outer walls of the stack or placing a thermoelectric device in contact with the stack. The system provides high thermal capacity but is easy to use and service.

Direct bonding of a titanium header to an embedded two-phase FEEDS cooling device for high-flux electronics

Abstract: High heat-flux electronics require novel thermal management solutions to push the current boundaries of state-of-the-art technologies on multiple fronts. A two-phase flow scheme that facilitates thin film evaporation in micro grooves via a microfluidics-enabled, enhanced fluid delivery system (referred to as FEEDS), is one such solution for transferring a very high heat flux with a manageable pressure drop, thus providing a very high coefficient of performance while meeting compactness and other related requirements. The design utilizes an array of parallel inlets and outlets to a microgrooved surface. One of the major challenges of a two-phase electronics cooling system is hermetically sealing the thermal management solution to the chip; in this case, it consists of a titanium header stacked on a microgrooved silicon chip. Titanium was chosen because of its low coefficient of thermal expansion close to that of silicon or silicon carbide compared to other alternatives. The two materials will not bond at moderate temperatures without intermediate metallization layers. In this study, a method for solder bonding of titanium to silicon was developed. One of the base requirements of the solder bond was to maintain a minimum of 5 MPa ultimate strength, which was met by utilizing innovative, thin, and low stress metallization processes A bonded manifold and chip were pressurized to burst to test the strength of the solder bond. Detailed procedures are described in this paper.