Appliance Design - April 2008 - (Page 25)

the depth and find more creative ways to add face area that you can draw air through.” Reductions in coil and package depth correlate to lower airside pressure drop through the heat exchangers. A lower airside pressure drop can allow the same fan to pass more air through a coil, or the fan size can be reduced to save energy and money. An example of finding ways to get more surface area can be found in some outdoor condensing units on which the coil follows the shape and structure of the unit, says Johnson. “Designing-in more face area usually means changing a cabinet or packaging shape or layout,” he says. Changing the shape of the cabinet could mean a significant investment in terms of tooling, design, and re-test, depending on the current design of the cabinet and each application is going to be a little different. “Starting fresh with a new package design that maximizes coil surface area, similar to an outdoor residential condensing unit, would be ideal, but is not always necessary,” he says. “In some applications, a microchannel coil can replace a larger RTPF coil allowing the existing cabinet or package to be used or even reduced in size. Each application really needs to be taken on a case by case basis to determine which coil technology is best.” To help determine which technology is best in a given application, Modine offers its customers a software package called MPower that was developed to aid its customers in the design of RTPF and Microchannel heat exchangers in vapor compression systems. Because the software is a system model, the user is able to see how changes to a heat exchanger affect the entire system, and not an individual heat exchanger. The Modine software was codeveloped with IMST, which is associated with the University of Valencia, Spain. The all-aluminum brazed fin construction of the heat exchanger is another benefit of the system, says Johnson. The microchannel coil components are joined together in a single coil using a nitrogen-charged brazing furnace. This is a one-shot brazing process in a brazing oven, as compared to 200- or 300-manually brazed connections on traditional copper and aluminum coils. Using allaluminum, as opposed to a copper/aluminum system, eliminates some of the problems of galvanic corrosion that can occur when disFor more Information Enter 108 www.applianceDESIGN.com AD02084CF.indd 1 applianceDESIGN April 2008 25 1/15/08 10:59:16 AM http://www.caereports.com http://www.appliancedesign.com

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Appliance Design - April 2008 Contents Editorial Shipments/Forecasts News Watch A Variant of Thermoacoustic Refrigeration Known as Acoustic-Stirling is Expanding Its Range Outside Cryocooling Into More Conventional Applications Such As Refrigeration and Air Conditioning Free-Piston, Stirling Coolers Are Now Showing Up in Mainstream Applications As Costs Come Down and Heat Transport Solutions Are Devised Heat Exchanger Innovations Are Helping To Improve the Overall Efficiency of Vapor Compression Systems Environmental Concerns Have Once Again Ignited a Debate Over Refrigerants A New Glass Ceramic Material for Induction Cooktops Can Be Decorated In a Variety of Glimmering Metallic, 3-D Looks That Can Employ a Number of Shades, Patterns, Styles, Colors, Intensities, and Textures Colorful, Reflective Coatings for Glass Create a Variety of Design Options To Help Designers Establish a Unique Look for Their Products Appliance Designers Faced With Different Motor and Drive Options Need To Understand the Differences and Tradeoffs Before Choosing A New MEMS Valve Offers a Number of Advantages Over Solenoids In Certain Applications, Including the Opportunity To Cut Energy Use The AHR Expo Set Attendance Records and Showcased Thousands of Innovative New Products Classifieds Design Marts Advertiser’s Index Association Report: CEA

Appliance Design - April 2008

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