Appliance Design - June 2008 - (Page 35)

FaNS & BlowErS Fan 560mm Benchmark Fan PAX (1) PAX (2) Q [CFM] 2068 2043 2432 Summary in-unit at Free-air 230V Q Speed Power [% more] [RPM] [W] 822 121.9 0 862 92.0 18 813 121.9 Power [% less] 25 0 ave SPl [dB] 57.4 54.2 53.7 Fig. 2. In developing solutions to improve efficiency of a condenser fan, PAX came up with two solutions. One required less power for equal airflow, while the other increased airflow for the same power as the existing baseline fan required. of fluid are the result of viscosity, changes in pressure, gravity, and other forces acting inside the fluid. The result of these efforts is a blade design whose curves and angles reduce turbulence before, during, and after air makes contact with the fan blade. Sometimes the number of fan blades change — one OEM went from using a fan with six blades to a fan that uses three blades. Often, the blades run at higher RPMs, but consume less energy. The geometry of the curved blades is such that the blades generate a vortex on their downstream sides. The fans “entrain” the air coming into the fan and accelerate air toward the center, creating a directed vortical flow that decreases turbulence. Traditional thinking in fan design was that producing laminar, straight-line flow was the best way to achieve smooth, non-turbulent flow. The PAX approach significantly departs from that conventional thinking by recognizing that vortical flow is the optimal path to achieving smooth, non-turbulent flow. In the same way a spiraling football or spinning bullet delivers a stronger and more stable trajectory, a vortical air-flow delivers a stronger and more stable stream of air. By taking this new approach, PAX engineers have been able to reduce energy requirements in fans and other rotors from between 10 and 85 percent, depending upon the application. The new blade design method also reduces noise levels from 30 percent to 75 percent, depending on the application. The actual shape and pitch of the blade, as well as the number of blades used, all depend on ALONE IS NO WAY TO BE COMPETITIVE IN THE GLOBAL MARKETPLACE With Fenwal® as your supplier of Gas Ignition and Temperature Controls, new products and markets are an opportunity, not a risk. We’ve put in place a top-tier global supply network to provide the performance and value you expect from Fenwal…at competitive prices. As a global manufacturer, we provide: • • • • • Qualified, proven production Strict material controls Local quality assurance Dedicated supply chain management On-time delivery to your destination Backed by Fenwal…the name OEMs trust. Don’t go it alone – contact us today. Call 508.881.2000 ext. 2104 or visit us at www.fenwalcontrols.com For more Information Enter 110 www.applianceDESIGN.com AD06084FEN.indd 1 applianceDESIGN June 2008 35 5/12/08 11:30:58 AM http://www.fenwalcontrols.com http://www.fenwalcontrols.com http://www.appliancedesign.com

Table of Contents Feed for the Digital Edition of Appliance Design - June 2008

Appliance Design - June 2008 Contents Editorial Shipments/Forecasts News Watch 21st Annual Excellence in Design Winning Designs Combine State-of-the-art Technology with . . . Meet the Judges Design Marts Fans & Blowers Mother Nature Has Her Own Ideas About Designing for Fluid Flow . . . Using CFD Simulation Software Early in the Product Development . . . Electronics Digital Signal Controllers Enable Digital Motor Control . . . Classifieds Meetings Advertiser’s Index Association Report: AHRI

Appliance Design - June 2008

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