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Reducing Energy Costs In Warehouses

Tue, 10/12/2010 - 10:23am
John Lytle, Application Engineer, Grove Gear

With the continuing trend of increasing energy demand and rising energy costs, conserving energy in warehouse facilities should be extremely important to industrial distributors.

Efficient warehousing and distribution centers are integral components of a business’ supply chain strategy, especially in today’s competitive global economy.  Electric motors are used in everything from driving conveyor belts to operating overhead doors.  Because of the essential part they play in operations, electric motors are a key component to reducing energy and operating costs. 

Industrial Sector and Energy Consumption

According to the U.S. Department of Energy (DOE), the industrial sector has been the country’s largest energy user, currently representing more than one-third of the country’s total energy consumption.  One component factoring into this excessive energy use is electric motors, which account for an estimated 65 percent of industrial electrical use.  Additionally, more than $30 billion is spent annually on electricity dedicated to electric driven systems, of which, nearly 70 percent goes to motor systems.1

With the continuing trend of increasing energy demand and rising energy costs, conserving energy is extremely important.  As you undoubtedly know, electric motors used in warehouses and distribution centers are almost always on, driving the energy bill higher.  But what if there was a way to reduce energy consumption and costs while increasing the efficiency level?  There is; through the use of gear reducers, which may be one of the most cost-saving components of a power transmission system.

When trying to improve overall system efficiency, most people initially look to the electric motor. And while it is true that switching to an energy efficient motor is a smart investment in most cases, this is only part of the overall energy savings equation.  According to the DOE, greater attention to power transmission system management can reduce motor energy costs by up to 18 percent while also boosting productivity, reliability and profitability.

Gear reducer options

Rising energy costs dictate the need for energy optimization to help businesses remain competitive. Facility and plant managers are always seeking ways to maximize profitability and minimize total cost of ownership.

Substantial energy and operating cost savings are gained by combining premium efficient motors with highly efficient gearing, and the choice of gearing can have a significant impact on energy usage. Gear reducers are commonly used for speed reduction and torque multiplication; however, during this process the gearing consumes a certain percentage of power. Obviously, as power losses are reduced or minimized, system efficiency improves.

Optimized components allow systems to perform at their best.  Gear reducers are components that, if appropriately sized for the application, provide reliability, measurable efficiency and optimal performance

Gear reducers are available in numerous materials, styles and configurations, and utilize a variety of gearing types, including worm, helical, spur, bevel and planetary.  Like motors, high efficiency gear reducers are becoming available to meet increasing standards and efficiency demands.

Worm gear reducers are the most common types of gearing today in the industrial marketplace because of their low initial cost, long service life and ability to withstand high overloads. However, one of the drawbacks of worm gear reducers is their relatively low efficiency: there is a lot of friction caused by the worm gear design and at high ratios this can cause the reducer to be only [approximately] 50 percent energy efficient.2  

Replacing them with in-line helical reducers, for example, offers energy savings from higher reducer efficiency and also provides the opportunity to reduce motor horsepower.  Here’s why – helical gearing technology delivers a wide range of ratios while maintaining 98 percent efficiency per stage of reduction; helical-bevel right-angle gearing technology delivers efficiencies of up to 95 percent.  Conversely, as stated, single stage worm gear reducer’s efficiency can be as low as 50 percent.3

The reason helical gearing is more efficient is a result of how the torque is transmitted between gears through rolling motion.  For a worm gear, torque is transmitted through sliding motion between the worm and the worm gear.  This sliding motion causes considerable friction and heat, which leads to greater efficiency loss than other types of gearing.

The efficiency of helical gear products ensures that a high proportion of the energy being input into the speed reducer is multiplied and transmitted into torque rather than being wasted on mechanical losses inside the gearbox.  Compact, high efficiency products are now available to directly interchange to most major brands of worm gear reducers.  This provides a unique combination of both compactness and outstanding power transmission efficiencies and offers the maximum speed reduction in the smallest package.

Mandates, Rebates and Incentives

The Energy Independence and Security Act (EISA) goes into effect December 19, 2010, and has far reaching implications for many industries.  While the act has numerous goals and mandates – 300 pages worth – the EISA addresses raising the efficiency of industrial electric motors and expands the range of motors that are in question.

Although not affected by the EISA legislation, high efficiency gear reducers can certainly lessen energy consumption.  Currently there is not legislation specifically for gear reducers.
However, a few of the industry’s forward-thinking manufacturers are proponents of Congress introducing laws targeting the efficiency of gear reducers.

Electric motors and their accessories may not be the highest-priority concerns of equipment buyers. But being aware of energy issues, both before and after purchase, can improve a facility’s “green profile”—in terms of both environmentalism and dollars. And, incentives, tax credits and accelerated depreciation are helping companies upgrade to premium motors and gear reducers, which decrease energy costs and lower CO2 emissions.

Following are a few examples that illustrate what states are both mandating and offering as incentives for upgrading to energy efficient technology.

California

Efficiency has been a key policy in California for 30 years, and it is widely credited with keeping per-capita power consumption flat.  But it’s also an ongoing battle.

“We’ve been so incredibly inefficient as an economy, as a society, that there is more and more to do,” said Dan Adler, president of the California Clean Energy Fund, a nonprofit venture fund set up in the wake of the energy crisis nearly 10 years ago. “The low-hanging fruit grows back when it comes to energy efficiency; you have to keep picking it.”

California’s legislature and governor realize that maintaining the economic health of California’s business and industry is vitally important but not at the cost of precious resources and emitting carbon.  To that end, in 2006, the Legislature passed and Governor Schwarzenegger signed AB 32, the Global Warming Solutions Act of 2006, which set the 2020 greenhouse gas emissions reduction goal into law.  Assembly Bill 32 will compel California companies to document by 2012 the steps they are taking to reduce carbon footprints, with a target of 20 percent reductions by 2020.

Surprisingly, because of California's massive and growing economy, the state is the 12th largest emitter of carbon in the world despite leading the nation in energy efficiency standards and lead role in protecting its environment. 4

Wisconsin

The Wisconsin Food Processing Plant and Food Warehouse Investment Credit is a refundable tax credit for businesses that have invested to modernize or expand food processing plants or food warehouses in Wisconsin and who have been certified by the Wisconsin Department of Commerce.

Tax credits are earned by incurring eligible expenses for modernization or expansion of a food processing plant or food warehouse.  This includes constructing, improving or acquiring buildings or facilities, or acquiring equipment for food processing or food warehousing.

Opportunity

It doesn’t matter whether a production, warehouse or distribution center is 10,000 square feet or one-million square feet, there is a strong business case for sustainable practices and operations: sustainability cuts costs and contributes to operating efficiencies. 

About 16 percent of commercial building space nationwide is warehouses, 5 which represents a significant opportunity for improved operations, lower operational costs and reduced environmental impact. Energy efficient motors that utilize gear reducers help facility managers value these changes not just from an environmental standpoint but from an economical one as well.

Gear Reducers in Action
Southern Wine and Spirits of American, Inc.
Delaware Distribution Center

Miami-based Southern Wine and Spirits of America, Inc., (Southern) founded in 1968, is a wholesaler and distributor of wines, spirits and beers operating in 30 states. It is known for its state-of-the-art distribution capabilities and superior customer service.

The company strives to grow the business while minimizing its environmental impact through efforts targeting saving energy and promoting sustainable environmental practices.

Small Change, Big Impact

With energy prices rising, energy conservation is a must for distribution centers. A few warehouse modifications can mean big savings.  Brian Greyerbiehl, maintenance manager at Southern’s Delaware distribution center (DC), knew that there had to be a more efficient way to maintain the conveyor system’s motor and gear reducers than continually purchasing and stocking eight gear boxes at a cost of $300 to $800 each. He wanted to modernize and upgrade the existing system and adopt a more energy efficient solution. 

The Delaware DC had maintenance-intensive worm gear reducers that often leaked and failed, causing excessive plant downtime.  Through the recent installation of one-of-a-kind HE24®, engineered and manufactured by Grove Gear™, Greyerbiehl was able to help bring the facility and its 3.75-mile conveyor system back on track.  The HE24 provides a dramatic 60 percent more torque than the previously used worm gear reducers, and uses optional mounting bases and existing bolt patterns to fit into the existing location without having to modify the conveyor.

Additionally, previously installed variable frequency drives (VFD) are also rated to be used with the new 2Hp standard, providing greater variability of the conveyor speeds. The use of the VFDs, combined with the HE24’s increased available torque, allows for the consolidation of distribution center ratios.

“It’s imperative for the DC to remain productive, yet at the same time I want to help reduce energy costs and consumption,” said Greyerbiehl.  “The HE24’s modular design and ease of assembly does this.”

As a result of installing the high-efficient gear reducer and replacing inefficient motors with premium efficient ones, Southern is now pursuing government rebates. 

“We’re realizing an immediate payback; I’m recommending this to all of Southern’s distribution centers throughout the United States.

John Lytle is an application engineer at Grove Gear and may reached at 262-878-8308, john.lytle@regalbeloit.com. Headquartered in Union Grove, Wis., Grove Gear manufactures standard and custom gear drives for industrial and specialty applications. Grove Gear is part of Regal-Beloit Corporation® (NYSE: RBC), a $2.25B Wisconsin-based manufacturer of efficient solutions for motion control and power generation serving markets around the world. For additional information: www.grovegear.com.

 

1. http://www1.eere.energy.gov/industry/bestpractices/motor_challenge_national_strategy.html

2. Werger, Jennifer. “Food Processing Machinery: Improving Energy Efficiency,” Applied Industrial Technologies, published 2009, FoodProcessing.com

3. Fulton, Mike.  “Maximizing Energy Savings by Replacing Motors and Reducers,” Plantservices.com.

4. http://gov.ca.gov/press-release/4111/

5. http://smartenergy.arch.uiuc.edu/pdf/Warehouse%20Niche%20Market%20Report.pdf

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