Appliance Design - June 2008 - (Page 36)

FaNS & BlowErS the particular application and is an area the company declines to discuss in detail. The fan blades are often matched to the motor output and the packaging that surround it. “In many situations, we seek to design a PAX solution that is fairly similar to the current existing solution, so that it is easier to integrate into the application,” says Shekar. And, these applications seem to be growing, as technology based on PAX’s streamline principle begins to enter the marketplace. To commercialize its technology, PAX Scientific granted master licenses to its spinoff companies, PaxFan, PaxIT, and PaxAuto. PaxFan holds the license for fans in the appliance, HVAC/R and industrial process segments. PaxIT is licensed for computer cooling applications. PaxAuto’s license covers engine and compartment cooling for automotive applications. These companies’s then license the technology to other companies and work with them to design products. Two such licensees are A.O. Smith Electrical Products, Tipp City, Ohio, and Delphi Corp., Troy, Mich. Testing at PAX, as well as Delphi and A.O. Smith, appears to bear out the claim of improved performance when using fans designed using PAX’s techniques. The tests examine different goals, whether it is to improve airflow output with the same size motor or get the same output with a smaller motor. In other applications, the goal is to reduce noise, and in some applications they are looking to achieve a combination of desired benefits. Sometimes, trade offs need to be made. At PAX, researchers have studied a number of cooling applications. In one example, a motor manufacturer asked PAX to develop new refrigerator evaporator fans to improve energy efficiency. The effort was part of the manufacturer’s actions to achieve Energy Star certification for the appliance. The application used a 95-mm fan operating in 0.03 in. H20. (See Fig. 1). The benchmark fan produced 58 cfm, while the PAX fan produced a comparable 57 cfm. At the same time, the PAX fan reduced power consumption some 25 percent, 5.55 W to 4.15 W, and reduced noise by half from 0.6 sone to 0.29 sone. (A sone is the perceived unit of loudness. One sone is roughly comparable to the sound a quiet refrigerator makes in a quiet room.) Another test looked at reducing noise and power usage in an air conditioner condenser fan. In this case, PAX developed two solutions to replace an existing 560-mm fan. (See Fig. 2). The first allowed for reduced torque to run the fan while achieving the same output. It achieved a 25 percent reduction in power in the air conditioning unit and a 3dba drop in fan and motor sound level. The first test consumed 92.0 W power, dropping from 121.9 W, and reduced noise from 57.4 db to 54.2 db. The second solution increased output 12 percent and decreased the fan motor noise by 4dba. Keeping the power requirement the same, 121.9 W, it generated more CFM, increasing from 206.8 to 243.2 cfm. Thus, the manufacturer was provided with two different options, one which would allow the product to feature more airflow, but consume the same amount of power, and the other a product that delivers less airflow, but consumes considerably less energy. Range hoods were also tested. In one case, the blade geometries reduced required shaft torque by 52 percent, which would have allowed the manufacturer to use a less expensive motor. For unrelated reasons, the project was not pursued, but if implemented, the manufacturer could have replaced a 4-pole barrel motor with a 2-pole C-frame motor and saved $3.50 per motor. For HVAC/R applications, A.O. Smith has done extensive studies of PAX fan designs and how best to integrate the technology with its motors. They are marketing their prototype fans to customers interest- Fig. 5. At the rated pressure and airflow, the PAX/A.O. Smith system showed a power reduction of nearly 23 percent. For more Information Enter 111 36 applianceDESIGN AD01084AmRad.indd 1 June 2008 11/30/07 9:37:11 AM www.applianceDESIGN.com http://www.AmericanRadionic.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

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.