September 2007

Unifin Announces Removable Cover Plate Generator Coolers

Unifin, a supplier of cooling equipment and transformer oil pumps and valves to the power generation and power transformer industries, has released its line of Removable Cover Plate (RCP) generator coolers. RCP coolers are used in new and existing power generation installations, from nuclear to hydro-electric to gas turbine power. Applications include both air cooled and hydrogen cooled generators.

Today's electrical generators produce not only electricity, but also heat from conductor resistance and from friction losses in the bearings. RCP coolers effectively remove this heat, in a system that is easy to clean and maintain. The RCP coolers feature Unifin’s plate fin technology, which provides optimal heat transfer efficiency and durability. Other fin surfaces are also available from Unifin. A removable, bolt-on cover plate facilitates access for cleaning while keeping the cooler installed, without disturbing the piping.

RCP coolers include a unique leak detector configuration available to prevent catastrophic failure of the motor or generator. The detector senses moisture before it can leak into the air. The Unifin leak detector system consists of a full double-tube construction, which provides additional protection against possible leaks caused by tube erosion.

The consistency and dispensing characteristics of FRV138 encapsulant make it a candidate for protection of delicate parts in applications where small or deep crevices must be filled. FRV138 encapsulant is heat curable at 90ºC and retains its elastomeric properties in a range of temperatures from -40ºC to 150ºC. The material can be applied to many substrates without the use of a primer.

New Mini Spring Clip Improves Air Filter Performance and Versatility

Universal Air Filter has introduced a new, low profile mini spring clip for electronics cooling air filters that makes them easier to install and service and improves their performance, especially in smaller filter applications where space is limited. Mini spring clips are perfect for 1U and 2U high chassis designs used in telecom, datacom, medical and military electronics applications.

Compact, lightweight and already installed on the filter assembly, these clips increase filter design options for filter installation, retention and replacement, eliminating the need to incorporate more expensive means of filter installation and removal provisions as part of the chassis manufacturing process. In addition, mini spring clips maintain positive contact with the chassis mounting slot and flanges, providing improved EMI shielding.

Skymark Performance Films Limited employs Arnitel VT thermoplastic ether ester block copolymer elastomer ( TEE-E) film technology materials from DSM Engineering Plastics, in Skymark’s breathable Skyair and Skyair XT membranes. Skyair and Skyair XT membranes offer different levels of moisture vapor transmission rate, and when laminated to fabric, can be used in recreational, sports, medical and construction applications which are waterproof and windproof, yet remain breathable. Because there are no pores in membranes made from the Arnitel material, Skyair and Skyair XT membranes retain their waterproof qualities even when water drops hit at high speeds, as on a motorcycle jacket worn while riding in the rain.

In textile-based uses, the breathability of Skyair and Skyair XT membranes affords comfort to wearers engaged in performance recreation and sports activities, even in extreme weather. In a completely different vein, the same attribute makes non-porous fabric made from Arnitel VT elastomer good for use as a roofing membrane in building construction, where it allows water vapor from the inhabited side to disperse into the outside air.

Other attributes especially fitting for the Skyair and Skyair XT usage of Arnitel include the material’s elasticity over a wide temperature range, excellent chemical resistance, high melting point and good adhesion to substrates.

Chomerics, division of Parker Hannifin Corp. has introduced T777, a new Polymer Solder Hybrid (PSH) Thermal Interface Material with superior thermal properties, enhanced thermal stability and excellent long-term reliability. T777 was developed collaboratively for next generation Intel microprocessors for mobile applications. It was optimized for Intel's Santa Rosa platform, Merom CPU and verified with Yonah test vehicle.

T777 pads are easy to handle during assembly and are readily re-workable. Unlike traditional phase change materials, PSH materials incorporate low-melt metal alloy fillers and polymer systems that maximize thermal conductivity, thermo-oxidative stability and surface wetting during flow. It reaches the bond-line thickness less than 0.001 inch (0.025 mm) and achieves minimum thermal impedance of 0.03°C-cm2/W. The microprocessor can then run at lower design temperatures with superior thermal performance. Long-term aging tests have shown that T777 does not have dry-out issues common to thermal grease materials and demonstrates relatively small change in end-of-life thermal performance after five years at 70°C.

New Findings Contradict Common Perception of Parallel Fan Efficiency

A new study from the American Society of Heating, Refrigerating and Air-Conditioning Engineers, and co-funded by the Air-Conditioning Engineers and Air-Conditioning and Refrigeration Technology Institute, has found that despite common perception, parallel fan-powered air-terminal units, which are used to distribute cooled or heated air in commercial building cooling systems, may not be more efficient than series fans.

When designing a cooling system, building designers can choose between either a series or parallel configuration for a building’s fan-powered, air-terminal unit. Since parallel fans run intermittently while a building is occupied, this configuration has been thought to be more efficient than series fans, which run continuously during the work day.

When no leakage occurs, the parallel fan terminals are more efficient, consuming 17 percent less energy than series fan terminals; however, tests showed that when leaks are present, series fans appear to outperform parallel fans. When a 20 percent leakage rate was introduced, the series terminal unit outperformed the parallel unit and used 5.5 percent less energy.
 
“For manufacturers and building design engineers, this research provides new insights into the magnitude of air leakage in parallel fan powered terminals and its impact on system operation and overall energy consumption,” said Karim Amrane, ARI’s vice president of policy and technology. “It also serves as a useful reference in prompting changes in design practices to provide more energy efficient building.” 

Combined US factory shipments of central air conditioners and air-source heat pumps for July totaled 637,606, down 3 percent from July 2006 shipments, according to the Air- Conditioning and Refrigeration Institute (ARI).

Year-to-date combined US factory shipments totaled 4.2 million, down 11 percent from the same period last year. Heat pump shipments for July totaled 169,417, down 7 percent from July 2006 shipments. Year-to-date heat pump shipments totaled 1.2 million, down 11 percent from the same period last year.

NanoDynamics subsidiary MetaMateria Partners has received of a one-year, $150,000 Phase I Small Business Technology Transfer (STTR) grant from the National Science Foundation. The grant will fund MetaMateria’s joint efforts with Purdue University and the Indium Corp. of America in advancing the development of a low-temperature, lead-free solder technology for heat-sensitive microelectronic, nanoelectronic and MEMS devices.

The program will specifically include MetaMateria’s nanometal preparation efforts, led by chief scientist Suvankar Sengupta; Purdue University’s evaluation of the nanometals’ melting characteristics, led by metal solder expert professor Carol Handwerker; and the Indium Corp.’s provision of flux components for the preparation of nanometal-containing solder pastes.

Based on a lowering of the bulk melting temperature using nanoparticles under 10 nm, the tin-, silver- and copper-alloyed nanometals employed in this project have exhibited preliminary melting depressions of 30ºC to 50ºC. The result of this project will be the development of lower-melting, lead-free solder pastes that can melt below 180ºC.

The grant will allow for further exploration into the behavior of nanometals when prepared in different ways and with different fluxes and organics. It is also intended to develop processes applicable to additional nanometals used in brazing and other joining techniques where lower melting temperatures are ideal.

Following successful completion of Phase I, MetaMateria will be eligible to submit a proposal for a two-year, $500,000 Phase II project to explore and test commercial applications for the developed technology. In addition to their work on this project, MetaMateria and Purdue University are active participants in the iNEMI electronics consortium project on nanosolder and low temperature electronics assembly and the development of lower melting lead-free solders.

A new class of catalysts created at the US Department of Energy's Argonne National Laboratory may help scientists and engineers overcome some of the hurdles that have inhibited the production of hydrogen for use in fuel cells.

Argonne chemist Michael Krumpelt and his colleagues in Argonne's Chemical Engineering Division used “single-site” catalysts based on ceria or lanthanum chromite doped with either platinum or ruthenium to boost hydrogen production at lower temperatures during reforming. “We've made significant progress in bringing the rate of reaction to where applications require it to be,” Krumpelt said.

Most hydrogen produced industrially is created through steam reforming. In this process, a nickel-based catalyst is used to react natural gas with steam to produce pure hydrogen and carbon dioxide.

These nickel catalysts typically consist of metal grains tens of thousands of atoms in diameter that speckle the surface of metal oxide substrates. Conversely, the new catalysts that Krumpelt developed consist of single atomic sites imbedded in an oxide matrix. The difference is akin to that between a yard strewn with several large snowballs and one covered by a dusting of flakes. Because some reforming processes tend to clog much of the larger catalysts with carbon or sulfur byproducts, smaller catalysts process the fuel much more efficiently and can produce more hydrogen at lower temperatures.

Krumpelt's initial experiments with single-site catalysts used platinum in gadolinium-doped ceria that, though it started to reform hydrocarbons at temperatures as low as 450°C, became unstable at higher temperatures. As he searched for more robust materials that would support the oxidation-reduction reaction cycle at the heart of hydrocarbon reforming, Krumpelt found that if he used ruthenium – which costs only one percent as much as platinum – in a perovskite matrix, then he could initiate reforming at 450°C and still have good thermal stability.

The use of the LaCrRuO3 perovskite offers an additional advantage over traditional catalysts. While sulfur species in the fuel degraded the traditional nickel, and to a lesser extent even the single-site platinum catalysts, the crystalline structure of the perovskite lattice acts as a stable shell that protects the ruthenium catalyst from deactivation by sulfur.

AVS offers the most respected and comprehensive science and technology meeting available for materials science and research. Activities include short courses, technical sessions (posters/oral presentations/invited speakers) and a large exhibition of scientific instrumentation, components, accessories, tools and services. This program covers applications and products in fields such as surface analysis and engineering; biomaterials; magnetics; MEMS/NEMS; nanotechnology; plasma science; thin film; vacuum technology; and electronic materials and processing. Exhibit attendance is free! For more information, visit www.avs.org.

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