AMCA International inmotion Magazine - Fall 2011 - (Page 8)

By TIM MATHSON, principal engineer for centrifugal, vane axial, and industrial products, Greenheck Fan Corp., Schoﬁeld, Wis.; and MICHAEL IVANOVICH, director of strategic energy initiatives, AMCA International, Arlington Hts., Ill. AMCA’s Fan Efﬁciency Grades: Answers to Frequently Asked Questions Learn what FEGs are and how they are applied for HVAC systems in commercial and industrial buildings. It has become clear that fan system design improvements and higher efﬁciency fans could have substantially reduced HVAC energy use in commercial and industrial buildings. Until recently, fan selection guidance and metrics that allow quick comparison of fan efﬁciencies have not been available. One approach has been to specify a fan efﬁciency rating based on the aerodynamic properties of the fan itself, and to specify where on the fan efﬁciency curve the fan operation point should sit. In essence, this is what AMCA International, working with ASHRAE’s TC 5.1 fan committee, has done with the development of a new fan efﬁciency classiﬁcation system, called the Fan Efﬁciency Grade (FEG). Work that began in 2007 to address fan efﬁciency classiﬁcations is now paying off. FEGs were formalized with the publication of AMCA 205 in 2010, and an AMCA Certiﬁed Ratings Program is now in place to provide third-party veriﬁcation of FEGs as speciﬁed in AMCA 211. This article answers questions that engineers, building owners, operators, regulators, and contractors may have about FEGs. What is a Fan Efﬁciency Grade? A fan efﬁciency grade (FEG) is a numerical rating that classiﬁes fans by their aerodynamic ability to convert mechanical shaft power, or impeller power in the case of a direct driven fan, to air power. Essentially, it reﬂects fan energy efﬁciency, allowing engineers to more easily differentiate between fan models: more efﬁcient fan models will have higher FEG ratings. FEGs apply to the efﬁciency of the fan only and not to the motor and drives. FEG ratings can be applied to custombuilt single fans and to series-produced fans manufactured in large quantities. In 2007, the ASHRAE Standing Standard Project Committee (SSPC) 90.1’s, mechanical subcommittee, invited ASHRAE TC 5.1, Fans, to participate in the development of the 8 FA L L 2 0 1 1 requirements for fan efﬁciency. An ad hoc working group was formed promptly. With assistance from the AMCA Fan Committee, the group ﬁrst developed a system for energyefﬁciency classiﬁcation of fans. The group recognized that a highly efﬁcient fan will operate inefﬁciently if used in the low-efﬁciency region of the fan curve. This led to a requirement that fans be speciﬁed within 10 percentage points of the peak total efﬁciency (Figure 1). Figure 1: A typical fan curve showing the 10-point total efﬁciency band. FEGs were developed by AMCA in response to regulators in the U.S. and abroad taking interest in reducing fan energy consumption and the environmental impacts of that consumption. Simultaneously, the International Standards Organization (ISO) was considering a similar efﬁciency rating for European energy standards and regulations. For the U.S. market, where fans are normally cataloged as bare-shaft fans and purchased with standard NEMA motors, FEGs were deﬁned through AMCA Standard 205-10, Energy Efﬁciency Classiﬁcation for Fans. AMCA Publication 211, inmotion W W W. A M C A . O R G A M C A I N T E R N AT I O N A L http://WWW.AMCA.ORG

Table of Contents for the Digital Edition of AMCA International inmotion Magazine - Fall 2011

AMCA International inmotion Magazine - Fall 2011
President’s Message
News
Code Watch
Fan Efficiency Grades: Answers to Frequently Asked Questions
Fans and Atrium Smoke Control
Fire Dampers and Smoke Dampers: The Difference is Important
Fan and Damper Guide Specs Update
Calendar

AMCA International inmotion Magazine - Fall 2011