Author Archives: akoss

Latest Qpedia has a new look!

As Qpedia is now in its 9th year of publication, we decided to give it a new look! We are pleased to release the new issue, showing off the fresh design. Download the issue.

Qpedia | Issue 94 cover

IN THIS ISSUE:

Improving Fin Efficiency with Thermosyphons

In electronics cooling applications, the heat sink geometry is typically decided by card-to-card spacing, resulting in height restrictions and therefore high fin efficiencies in the range of 80-90%. Because of this, fin efficiency has yet to be fully explored. This article will discuss the use of thermosyphons as one method for improving fin efficiency and improving the heat sink’s thermal performance.

Heat Flux Measurement for Zhaga Standardized LED Light Engines

The Zhaga consortium, a worldwide organization, aims to standardize LED light engines. Standardization is essential when there is the need to ensure exchangeability of LED based Luminaires. Zhaga consortium is working to develop standard specifications for the various interfaces of LED light engines. A complete interface consists of the description of Mechanical, Optical, Electrical and Thermal specifications. In this article we will focus on one aspect that is covered in the thermal interface specification.

Industry Developments: Heat Exchangers

Heat exchangers are found in a variety of environments. In electronics cooling, the outward portion of a heat exchanger uses either ambient air or water in the cooling process. A heat exchanger can’t cool an enclosure or a device below the temperature of the air or water, so its vital to anticipate worst-case scenarios in order to ensure proper cooling. This article discusses air-to-air and liquid-to-air indoor and outdoor heat exchangers for a variety of electronics cooling applications.

Technology Review: Heat Pipes in Heat Exchangers

Qpedia reviews innovative technologies developed for electronics cooling applications. This section presents selected patents that were awarded to developers around the world to address cooling challenges. In this issue our spotlight is on application of heat pipes in heat exchangers and its application in the thermal management industry.

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How Does the Wick and Orientation of a Heat Pipe Affect its Performance?

Heat pipes are used in a wide variety of applications, particularly in the aerospace, military and consumer electronics industries. A heat pipe is self-driven, two phase device used to transport heat from one end to the other. The liquid evaporates and turns to vapor on the heat pipe’s hot end (also known as the evaporator) where it then flows to the cold end (also known as the condenser) and liquifies. wick_type_structuresThe heat transfer ability of a heat pipe is determined by its diameter, fluid type, wick structure, and orientation. The Qpedia article, “How Wicks and Orientation Affect a Heat Pipes Performance” will review the different types of wicks and other factors that need to be considered when selecting a heat pipe for specific applications.

How to Design Efficient Fans for Electronics Cooling Applications

In modern day equipment racks, the power consumed by the cooling fans represents a significant percentage of the overall system power budget. With the advent of data centers and their large energy costs, the issue of “cooling power” is exacerbated. It is, therefore, becoming crucial to design and implement methods for reducing data centers’ power consumption. The Qpedia article, “Designing Efficient Fans for Electronics Cooling Applications,” presents a review of methods available for reducing energy consumption through increasing fan efficiency. Three main ways of improvement by optimization will be discussed: motor and electronic driver optimization, fan aerodynamic optimization and surrounding inlet/outlet equipment optimization. fan

 

New Qpedia Issue Published

This month’s Qpedia Thermal eMagazine has just been released and can be downloaded at qats.com.

Qpedia Thermal eMagazine | October 2014

Featured articles this month include:

Heat Transfer Calculations of a Thermosyphon

A thermosyphon is a simple device that can be used to transfer large amounts of heat without moving parts. The limitations of the device are similar to those of a traditional heat pipe with a wicking structure, but thermosyphons provide cost savings over common heat pipes. This article will discuss heat transfer calculations that can be used for thermosyphon pipe selection.

Data Center Hybrid Cooling: A Cost Saving Method

Data centers are the core of the information economy, representing government and academic institutions, financial, medical, media and high-tech industries. However, accelerating power consumption, environmental concerns and the cost of energy have created the need for change in data center design and thermal management. This article discusses the benefits of hybrid cooling compared to traditional air cooling of data centers.

Industry Developments: Porous Heat Sinks

Heat sinks are typically made from non-porous materials that are impermeable to water, air and other fluids, most commonly aluminum and copper. However, studies and applications have shown that porosity features can provide better heat sink performance. This article discusses recent developments on heat sinks that are made from semi-porous materials or with porous coatings.

Technology Review: Application of Phonons in Heat Transfer Devices

In this issue our spotlight is the application of phonons in heat transfer devices. There is much discussion about its deployment in the electronics industry and these patents show some of the salient features that are the focus of different inventors.

Cooling News

The latest product releases and news from around the electronics cooling industry.

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First Qpedia of 2015 Released

The first Qpedia Thermal eMagazine of 2015 has just been released and can be downloaded at: http://www.qats.com/Qpedia-Thermal-eMagazine/Back-Issues

Qpedia_Sept14_cover

Featured articles in this month’s issue:

Modeling Vapor Chambers as a Heat Spreading Device in CFD

Despite the ongoing trend which demands higher power dissipation with smaller devices, the proper junction temperature must be maintained in order to meet performance and reliability requirements. This article discusses how vapor chambers can be modeled in CFD for effective spreading of the heat dissipation of a component which is smaller than a heat sink.

Application of TEC Using a Heat Exchanger for Sub-Ambient Liquid Cooling

Thermoelectric modules are a compact electronics cooling option for applications that require simple integration, quiet operation and acceptable reliability. Though sub-ambient temperatures can be achieved with the application of thermoelectric modules, they come with the limitation of heat flux resulting in lower coefficient of performance. This article examines how using a thermoelectric chiller can overcome a thermoelectric module’s limitation and be a beneficial electronics cooling method.

Industry Developments: Advanced Packaging Materials for Electronic Components and Systems

A number of high performance materials are now available for electronic housings and packages and provide advantages over traditional choices. Advanced composites are lighter, more weather resistant and have increased reliability and thermal performance. This article will review the latest advanced packaging materials that are available on the market and discuss the thermal management and electronics packaging benefits they hold.

Technology Review: Heat Exchangers Using Two-Phase Flow

In this issue our spotlight is on heat exchangers using two-phase flow. There is much discussion about its deployment in the electronics industry and these patents show some of the salient features that are the focus of different inventors.

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