One of a series of industrial energy efficiency sourcebooks ImprovingImproving FanFan SystemSystem PerformancePerformance a sourcebook for industry NT O E F E TM N R E U.S. Department of Energy A R P G E Y D U A N Energy Efficiency and Renewable Energy C I I T R E D E M Bringing you a prosperous future where energy is clean, ST A ATES OF abundant, reliable, and affordable Acknowledgments Improving Fan System Performance: A Sourcebook for Industry has been developed by the U.S. Department of Energy’s (DOE) Industrial Technologies Program and the Air Movement and Control Association International, Inc. (AMCA), a DOE Allied Partner. Industrial Technologies and AMCA International undertook this project as part of a series of sourcebook publications on motor-driven equipment under the BestPractices effort. Other topics in this series include compressed air systems, pumping systems, and motors and drives. For more information about the Industrial Technologies’ BestPractices effort and AMCA International, see Section 3. AMCA International is a not-for-profit association of the world’s manufacturers of related air system equipment—primarily, but not limited to fans, louvers, dampers, air curtains, airflow measurement stations, acoustic attenuators, and other air system components—for industrial, commercial, and residential markets. The association’s mission is to promote the health and growth of industries covered by its scope and the members of the association consistent with the interests of the public. DOE, AMCA International, Lawrence Berkeley National Laboratory, and Resource Dynamics Corporation thank the staff at the many organizations that so generously assisted in the collection of data for this sourcebook. The contributions of the following participants are appreciated for their review and input to this sourcebook: Gary Benson, The New York Blower Company Frank Breining, Airmaster Fan Company Don Casada, Diagnostic Solutions, LLC Brad Gustafson, U.S. Department of Energy Tom Gustafson, Hartzell Fan, Inc. Tony Quinn, American Fan Company & Woods USA Division Paul Saxon, Air Movement and Control Association International, Inc. Bill Smiley, The Trane Company Sastry Varanasi, ABB Fan Group North America Dick Williamson, Twin City Fan Companies, Ltd. Ron Wroblewski, Productive Energy Solutions Prepared for: The United States Department of Energy Air Movement and Control Association International, Inc. Prepared by: Lawrence Berkeley National Laboratory Washington, DC Resource Dynamics Corporation Vienna, VA Cover photo credit: Copyright© CML Northern Blower Inc., 1989. All rights reserved. This image may not be reproduced, stored, or transmitted in any form or means without the prior written consent of the copyright holder. Contents Quick Start Guide 1 Section 1: Introduction to Fan Systems 3 Fans 3 Fan Performance Curves 6 Fan System Components 9 Section 2: Performance Improvement Opportunity Roadmap 15 1—Assessing Fan System Needs 17 2—Fan Types 19 3—Basic Maintenance 25 4—Common Fan Systems Problems 29 5—Indications of Oversized Fans 33 6—System Leaks 37 7—Configurations to Improve Fan System Efficiency 39 8—Controlling Fans with Variable Loads 43 9—Fan Drive Options 47 10–Multiple-Fan Arrangements 51 11–Fan System Economics 55 Section 3: Programs, Contacts, and Resources 59 Industrial Technologies Program and BestPractices 59 Air Movement and Control Association International, Inc. (AMCA International) 63 Directory of Contacts 65 Resources and Tools 67 Appendices 75 Appendix A: Fan System Terminology 75 Appendix B: The Fan System Marketplace 83 A Sourcebook for Industry i ii Improving Fan System Performance Quick Start Guide Quick Start Guide This sourcebook is designed to provide fan system ◆ Section 3: Programs, Resources, and Contacts users with a reference outlining opportunities to Section 3 provides a directory of associations and improve system performance. It is not intended to other organizations involved in the fan marketplace, be a comprehensive technical text on improving along with a listing of the resources, tools, software, fan systems, but rather a document that makes users videos, and workshops. aware of potential performance improvements, provides some practical guidelines, and details where ◆ Appendices the user can find more help. The sourcebook is The sourcebook includes two appendices. Appendix A divided into three main sections and appendices. is a glossary that defines terms used in the fan system industry. Appendix B presents an overview ◆ Section 1: Introduction to Fan Systems of the fan system marketplace. For users unfamiliar with the basics of fans and fan systems, a brief discussion of the terms, relationships, The Systems Approach and important system design considerations is provided. This section describes the key factors involved in fan selection and system design and The cost-effective operation and maintenance of a provides an overview of different types of fans and fan system requires attention not only to the needs the applications for which they are generally used. of the individual pieces of equipment, but also to Users already familiar with fan system operation the system as a whole. A “systems approach” may want to skip this section. The key terms and analyzes both the supply and demand sides of the parameters used in selecting fans, designing system and how they interact, essentially shifting systems, and controlling fluid flow are discussed. the focus from individual components to total system performance. Often, operators are so focused ◆ Section 2: Performance Improvement on the immediate demands of the equipment that Opportunity Roadmap they overlook the broader question of how system This section describes the key components of a fan parameters are affecting the equipment. The system and the opportunities for performance improve- systems approach usually involves the following ments. Also provided is a figurative system diagram types of interrelated actions: ■ identifying fan system components and performance Establishing current conditions and operating improvement opportunities. A set of fact sheets parameters ■ describing these opportunities in greater detail Determining present and estimating future follows the diagram. These fact sheets cover: process production needs ■ Gathering and analyzing operating data and 1. Assessing Fan System Needs developing load duty cycles 2. Fan Types ■ Assessing alternative system designs and 3. Basic Maintenance improvements 4. Common Fan Systems Problems ■ Determining the most technically and 5. Indications of Oversized Fans economically sound options, taking into 6. System Leaks consideration all of the subsystems Configurations to Improve Fan System Efficiency 7. ■ Implementing the best option 8. Controlling Fans with Variable Loads ■ Assessing energy consumption with respect to 9. Fan Drive Options performance 10. Multiple-Fan Arrangements ■ Continuing to monitor and optimize the system 11. Fan System Economics ■ Continuing to operate and maintain the system for peak performance. A Sourcebook for Industry 1 2 Improving Fan System Performance Introduction to Fan Systems Section 1: Introduction to Fan Systems Fans1 are widely used in industrial and commercial often causes system designers to design fan applications. From shop ventilation to material systems conservatively. Concerned about being handling to boiler applications, fans are critical responsible for under-performing systems, designers for process support and human health. In the tend to compensate for uncertainties in the design manufacturing sector, fans use about 78.7 billion process by adding capacity to fans. Unfortunately, kilowatt-hours2 of energy each year. This con- oversizing fan systems creates problems that can sumption represents 15 percent of the electricity increase system operating costs while decreasing used by motors.3 Similarly, in the commercial fan reliability. sector, electricity needed to operate fan motors composes a large portion of the energy costs for Fans that are oversized for their service requirements space conditioning. do not operate at their best efficiency points. In severe cases, these fans may operate in an unstable Performance may range from “free air” to several manner because of the point of operation on the pounds per square inch gage (psig)4, with fan airflow-pressure curve. Oversized fans generate airflow from a few cubic feet per minute (cfm) excess flow energy, resulting in high airflow noise to more than 1 million cfm. Pressures above and increased stress on the fan and the system. 15 psig generally require air compressors, which Consequently, oversized fans not only cost more to are addressed in a separate sourcebook titled purchase and to operate, they create avoidable Improving Compressed Air System Performance, system performance problems. The use of a A Sourcebook for Industry. “systems approach” in the fan selection process will typically yield a quieter, more efficient, and In manufacturing, fan reliability is critical to plant more reliable system. operation. For example, where fans serve material handling applications, fan failure will immediately Fans create a process stoppage. In industrial ventilation applications, fan failure will often force a process to be shut down (although there is often enough There are two primary types of fans: centrifugal time to bring the process to an orderly stoppage). and axial. These types are characterized by the Even in heating and cooling applications, fan path of the airflow through