ebm-papst Fans, Blowers and Technology

Turbulence. It happens. Luckily, ebm-papst has a solution for noisy systems.

If you’ve tossed and turned at night, unable to sleep because of humming sounds from your home’s air conditioner, you know these noises are intolerable. That same distraction from a heating or A/C system can strike anywhere… in the office, at the store, at a restaurant.

But did you know that it’s usually the turbulence in an air-moving system – not the components – that makes your ears ring?

Fans are an essential part of today’s refrigeration, air conditioning and ventilation systems.  They are designed and tested to minimize noise in thousands of applications. However, there are wide differences in how fans are installed and configured, the conditions in which they operate, and their location within the air system. These variables can create air inflow and outflow disruptions that raise the ‘loudness level.’

For example, the housing walls of rectangular heat exchangers can generate a backflow that creates pressure fluctuations on the fan blade. These turbulence ‘vortexes’ drastically increase a fan’s low-frequency (tonal) noise. While it’s not possible to compensate by changing the fan itself, it is possible to straighten the flow of air moving into the fan and balance the pressure of air moving out of the fan.

Over the past few years, ebm-papst has developed two passive add-on devices — the FlowGrid air inlet grill and the AxiTop diffuser. In distinctive ways, each improve how air moves into and out of our axial and centrifugal fans.

The FlowGrid air inlet grill has a straightening effect on the inflowing air, reducing acoustical levels and considerably reducing tonal noise.

In a condenser application, fitted with an axial fan, the FlowGrid air inlet grill reduces overall sound levels by 3.9 dB(A) and tonal noise by 16 dB. In a low profile (250 mm diameter) air conditioning device, the FlowGrid reduces sound levels by 2.5 dB(A) and reduces tonal noise by 9 dB.

While FlowGrid works to reduce low-frequency noise on a fan’s inlet side, the AxiTop diffuser reduces mid-frequency noise on the fan’s discharge side. How does this work? AxiTop operates like a reverse nozzle, increasing pressure and significantly reducing discharge losses. Efficiency increases and operating noise decreases.

Using both AxiTop and FlowGrid on a condenser fitted with a 31.5 inch (800 mm) axial fan, with outside air drawn through a heat exchanger, we’re able to reduce the fan’s noise level by 5.8 dB(A) and tonal noise by 20 dB.

Setting new standards for their quiet, energy-efficient operation, both devices are advancing technology and creating ideal operating conditions for fans. As a result, we can all sleep better!

Contact our application engineer for additional information at 860 674-1515 or by e-mail at sales@us.ebmpapst.com.

by Lou Moffa, Market Manager – Commercial Refrigeration

Last week, my colleague Joe Giacona talked about why ventilation is critical within food transport refrigeration. With many fresh foods making an average journey of 1,500 to 2,000 miles from their source, well-engineered refrigeration systems and fine-tuned logistics ensure that these fragile foods remain delicious no matter their destination.

This week, we continue the food chain journey through the supermarket right before it is purchased for use at your home. As with the containers inside ships and trucks, consistent and efficient refrigeration in holding warehouses and at the supermarkets themselves provide a slowing of the clock to help maintain food as long as possible. Commercial refrigeration systems must maintain safe temperatures; perform reliably and efficiently while working continuously in the background.

In keeping with our company’s GreenTech philosophy, ebm-papst developed a specialized line of air movers to help refrigeration engineers meet their critical design objectives. The ecological benefits are achieved with features such as programmable speeds to dial in the exact air needed, two speed fans that allow the fan to change speeds without complicated wiring or variable speed operation that allow ebm-papst fans’ EC motors to operate over a full RPM range to match the cooling performance needed without wasting energy. These various features are found in our product line so it is easy to choose the right air mover for the refrigeration system. Our small mounting footprint and quiet operation provide refrigeration designers with exciting new approaches to solving old problems.   

To help your local supermarket maximize your food shopping experience, our fans are designed into various refrigeration systems that you will see in a typical supermarket.

Once the food products arrive at the supermarket they are unloaded from the trucks and usually placed in a "walk in" cooler (or freezer). Most walk in coolers are near the loading docks at the back of the store hidden from public view.  Even if you have not been behind the scenes, you still have encountered them during your recent shopping. One side of the unit cooler is typically made out of glass display doors that are open to the public. Fast moving items like the milk in a supermarket or the beer in a liquor store have doors that you open so that you can select your product. Since these products are usually in the back of the store, they are against a wall near the loading docks so they can be restocked with little effort. This allows the store to keep large inventories of product and have it appear so that it is always stocked. Next time you open one of those doors, peak in behind the milk or beer, if you don't see the fans up above, you will hear them running as well as feel them move the air around the area.  Fans are needed to keep the air in constant circulation within these cases to help keep the products cool.

The other key refrigerated areas of a supermarket are the display cases that hold fruits, vegetables, frozen foods and every other possible food product including recently refrigerated pet foods in the pet food aisle. These display cases must perform two important tasks: They must keep food at a constant and precise temperature, and present the food in a way that shoppers can easily see it, want it and ultimately put it in their shopping carts. This is not an easy task but our ebm-papst EC fans meet the challenge even while they are subjected to constant cold temperatures, moisture from misting systems and the bumps and jarring from stocking these cases every day.

The reach in bottle cooler is another example of a refrigeration system that is in constant operation, keeping soda and water cool for impulse purchases. ebm-papst EC fans are used on both the hot (condenser) side and the cold (evaporator) side. Your home refrigerator has it easy compared to what a bottle cooler goes through every day. Multiple opening and closings and constantly being loaded with room temperature products gives these coolers a workout. Our fans keep refrigerated air in constant circulation to help cool down product as quickly as possible.

Our last stop on how fans are used in our supermarket, ends with a birds-eye of the condenser units on the rooftop. All of the reject heat from the refrigeration systems throughout the store is sent to the rooftop condensers. Our variable speed, EC Giant series of fans are installed here and are running at just the needed speed to cool down the refrigerant. Variable speed helps increase efficiency compared to running standard fans in an on and off manner.  By adding our latest AxiTop diffuser these EC Giants are operating quietly so that there is no unnecessary noise pollution and they are providing increased efficiency to help supermarkets further reduce their utility bills.

 
Whether it’s on a boat, in a truck or ready for supermarket display, our local, national and internationally-sourced food depends on reliable and efficient fans to help refrigeration systems to equalize air flow and save energy. To learn more, visit our new market solutions tool and click on “Refrigeration.”

Read part 3 of this blog series: What's that fan doing in my food chain? Part 3

About Lou Moffa
With his 11+ years experience with ebm-papst Inc., Lou Moffa listens to the challenges our customers face and recommends air-moving solutions that help refrigerant system engineers, warehouse owners and supermarket managers keep food fresh across a variety of storage and display environments. As the company’s market manager – commercial refrigeration, Lou holds an automated manufacturing engineering degree from Waterbury State Technical and a Bachelor of Science in Manufacturing Engineering from Central Connecticut State University. In his free time, Lou enjoys tackling renovation projects around his home, cooking and exploring new food shopping experiences.

Compact, efficient FlowGrid air-inlet grill from ebm-papst  significantly reduces noise spectrum for
axial and centrifugal fans

Whether it’s heat pumps in the home, condensers in supermarket refrigerators or ventilation systems on the production floor, FlowGrid, the innovative patent-pending air-inlet grill from ebm-papst, is dramatically reducing noise levels for fans installed within limited-space air moving equipment.

What our award winning AxiTop diffuser does on the pressure side (outlet)
of the fan, FlowGrid does on the suction side (inlet). Easily mounted to applications with ebm-papst fans and backward curved impellers, its open grill design straightens airflow to minimize turbulence before the air hits the axial or centrifugal impeller blades. FlowGrid is ideal for fans installed within flat and central air handling units, air purifiers and heat pumps with centrifugal fans, or air-water heat pumps, condensers and V-shaped condensers
with axial fans.

“FlowGrid is the result of our extensive airflow testing for inlet conditions with a wide variety of customers’ axial and centrifugal fans across dozens of applications,” said George Riker, business development. “By improving the aerodynamic conditions external to the fan, FlowGrid reduces the adverse effects of these inlet conditions and
minimizes noise.”

Here’s how noise happens within a fan and how FlowGrid corrects it:

1. When the walls of a device such as an air handler, heat exchanger or heat pump are different distances from the fan, powerful vortices combine in the narrowest areas to form so-called ‘vortex strings.’

2. These turbulences then hit the rotating blades of the fan, generating noise – specifically a broadband noise and additional narrowband, tonal frequency components, known as propeller noise or tonal noise.

3. Mounted on the air intake side of the fan, the FlowGrid weakens these ‘vortex strings’ as they flow through the device.

4. This reduces sound pressure across the entire sound frequency range and especially in the low frequency tonal range.
   
   

Apart from reducing overall sound pressure, the most drastic reduction is in low-frequency blade-passing noise (the sum of the fan speed and the number of blades) caused by blades cutting through turbulence within small space applications such as heat exchangers. The FlowGrid grill has been proven in certain applications to reduce overall sound pressure levels by as much as 3.9 dB(A), and these blade passing frequencies by up to 16 decibels.

With FlowGrid, ebm-papst is making a clear contribution to passive noise reduction – a big part of our GreenTech philosophy. It can help manufacturers and ventilation specifiers comply with noise regulations and improve the environment for employees who work near ventilation equipment. The innovative air-intake grills, which require less acoustic insulation, work with both axial and centrifugal fans without reducing their performance. Using them can help to reduce or entirely avoid the use of cost-intensive, active noise-reduction measures.

For additional information about how FlowGrid can make a difference in your application, contact one of our application engineers today at 860 674-1515 or sales@us.ebmpapst.com.

by Bob Sobolewski - President & CEO

If one thing was evident at last month's Air Conditioning, Heating and Refrigeration (AHR) Expo in New York, it's that innovation and sustainability must go hand in hand.

AHR provides us with an opportunity to meet our partners, suppliers and customers face to face. Every year, the show renews our belief that energy savings and resource conservation are a priority. It renews our commitment to our GreenTech philosophy: that every product we develop must exceed its predecessor in terms of efficiency and economy.  At this year’s expo, we gave a group of editors and industry experts a re-cap of our company’s achievements in 2013.

2013 Growth
2013 marked the 50^th anniversary for the ebm-papst Group. Founded by Gerhard Sturm and Heinz Ziehl in 1963 with only 35 employees, the company now has 11,400 employees at 57 sales offices and 18 production facilities worldwide. ebm-papst Group grew 10 percent to around 730 million euros ($993 million) for the first half of the current fiscal year (April 1 - September 30, 2013). Over the past three years, the global company has grown by 37 percent.

The double-digit growth of ebm-papst USA last year was fueled by a growing need for climate control across nine major markets and the applications within each, as well as employees’ focus on exceeding customer needs.

Awards for AxiTop
The epylen wood-plastic composite AxiTop diffuser, introduced in 2012 as a new, passive component in ebm-papst 800 and 910 mm series fans, recently earned ebm-papst top honors at the MATERIALICA trade fair in Munich. AxiTop was honored in the Material category for its combined energy savings, noise reduction and energy efficiency.

US production of Axial and RadiPac fan assemblies
Over the past decade, we’ve expanded our product portfolio into much larger dimensions. Ten years ago, a large ebm-papst fan was 500mm to 630mm in diameter. Now, we’re selling fans up to 1.5 meters in diameter that are used in large-scale refrigeration and ventilation applications.

To increase responsiveness to our NAR customer base, we began localizing production of our larger axial fans, which are typically used in condensers and chillers, and for our RadiPac backward curved impellers used in rooftop A/C units, computer room A/C units and other applications.

Localizing production of these fan models also helps us customize the venturi, housing, mounting and paint color specs to customers’ requirements, speed turnaround and further reduce our transport-related carbon footprint.

GreenTech in practice at our Farmington, CT production facility and offices
Last year, our production facility completed installation of a new large capacity powder paint application system complete with an automatic feed system and new spray guns. The guns allow for more even coating and better use of powder at lower air pressures – further reducing powder spray waste and improving paint quality. The new powder paint system’s dual cyclone technology feeds back (recycles) the 40% of powder that hits the parts and falls into the bottom of the paint booth – increasing our actual powder usage efficiency to about 95%. As a result, production has increased our powder spray efficiency, disposed of less scrap powder, achieved higher quality for painted parts, and significantly reduced color change times.

We also replaced all highbay lights in our production facility and warehouse, and all outdoor lighting around the plant with new energy efficient LED fixtures. Energy savings for this recent installation will be measured throughout 2014.

A comprehensive new high-efficiency 15-unit HVAC system with an average Seasonal Energy Efficiency Ratio (SEER) rating of 12.0 is being installed to replace a circa-1999, 9.0 SEER-rated 200 ton cooling system on the roof of our US headquarters. Based on today’s energy rates, we expect that these new HVAC units will save the company 20% per year in electricity expense. To further boost efficiency, a sophisticated web-based control system will allow for in-house and remote monitoring. What’s more, the new HVAC units employ ebm-papst impellers!

by Lou Moffa, Market Manager - Refrigeration

Take a walk outdoors in any suburban area and it is difficult to avoid the sounds created by the mechanical inventions in our modern society.  The drone of an aircraft passing overhead, the rush of vehicles from a busy street or the buzz of a lawnmower in the neighbor's yard create a measurable soundtrack to our daily activities.  Most of us are pleasantly surprised by just how quiet it becomes when these sounds suddenly stop and we are exposed to the underlying level of quiet that is present.  We cannot eliminate these noises entirely, but by applying our GreenTech philosophy of continuous design improvement during our product development, ebm-papst can again help engineers create air moving systems that are found outdoors that we can comfortably live with. 

In congested cities, with living spaces adjacent to supermarkets and small industry, the need for quiet operation is not just desired, it is mandatory by local codes.   Fans that are used to move large amounts of air to cool our mechanical equipment or keep our refrigeration systems running are necessary components in the systems that are placed on rooftops and the outside of our buildings.  Engineers and designers work very hard to meet the strict guidelines that are put in place to limit noise but these restrictions can negatively affect their final designs.

To lower noise in these applications, there are standard "fixes" that the designer can call upon to help meet the required noise and performance levels.  With axial fans, the common fix is to reduce the motor RPM and increase the number of fans to handle the air performance needs and or increase the blade size.  These solutions can lead to a reduction in system performance, add components increase the system footprint and increase energy consumption.   Not an appealing solution with today's high electrical costs, small installation areas and increased refrigeration costs.  Even worse, in many cases, these changes are not always effective and further fixes must be done on site where additional changes are even more costly. 

AxiTop from ebm-papst, a leader in air moving technology, offers a groundbreaking solution.  We have combined our high efficiency AC and EC axial fans with a passive diffuser assembled in one complete package to help simplify installations.  Our optimized AxiTop design has been shown to reduce noise lower energy consumption when installed in typical applications.  Integration of this assembly is simple.  The fan and diffuser are delivered as a complete assembly that can easily be integrated into an existing design using our standard square wall plate.  Or custom wall plates are available so that the AxiTop fan assembly can be integrated seamlessly into your air handling system.  

AxiTop is currently available worldwide in 800 and 910mm diameter axial fans.  These popular sizes are perfectly suited for use on rooftop condensers, fluid coolers, and agricultural ventilation applications.

If you need a real solution to meet applications with low noise requirements and at the same time reduce total cost of ownership and simplify your design, our AxiTop product line provides an answer! 

Please visit us at booth #2967 at the upcoming AHR Expo in Dallas, TX, to see the AxiTop units on display and for a complete overview of this exciting new product. Or contact us at sales@us.ebmpapst.com to review the benefits of using AxiTop.