ebm-papst Fans, Blowers and Technology

by Matt Menard, Market Manager - Air Conditioning

In the world of HVAC, motors move conditioned air throughout the system. When a motor fails, cooling or heating ceases, leaving occupants of that building uncomfortable. The motor can be replaced relatively quickly with an experienced technician. However, diagnosing what caused the failure is difficult, time consuming and often ignored.

Motor failure is a major headache that can cost building owners significant money. With limited budgets and resources, implementing a preventative maintenance program on motors to minimize failures can be difficult for most. So what is the solution?

The December 9 issue of ACHR News discusses causes and prevention of motor failure. All of these types of failure can be avoided by choosing external rotor EC motor technology, such as is utilized in ebm-papst’s product line, to boost reliability and efficiency.

1. Belt — Belt tension is critical in avoiding vibrations between the fan wheel and motor. Belts tend to stretch throughout their lifetime, so technicians tend to over tighten during replacement. A belt that is too tight overloads the motor and shortens the lifespan. ebm-papst external rotor motors do not use belts—the fan wheel is mounted directly to the motor rotor.

2. Overheating — This is the most common cause of failure. Dirt buildup on the fan wheel and poorly designed/installed ductwork causes additional strain on the motor resulting in overheating and a shortened lifespan. ebm-papst EC motors have temperature sensors built into the internal electronics package that act as a safety device in the case of overheating.

3. Electrical Fluting — When utilizing a Variable Frequency Drive (VFD) for speed control, users can experience a phenomenon called electrical fluting, which basically equates to a mini-lightning storm that occurs within the motor as voltage and frequency are regulated by the VFD. This ‘storm’ affects the bearings, resulting in premature failure. Electrical fluting is unpredictable and requires additional measures such as shaft grounding kits and ceramic bearings to prevent. ebm-papst EC motors have built-in speed control and do not require a VFD, eliminating the electrical fluting issue.

In addition to eliminating belts, adding temperature sensors and built-in speed control, industry experts such as Jim Connell of AirXChange Inc. believes that ECM fans are more reliable and use less energy than traditional AC motors and drives.  Utilizing external rotor EC motor technology provides not only the most reliable, but most efficient technology available.

By Matt Menard, Market Manager - Air Conditioning

Imagine it’s a sweltering day, and you’ve entered a nice cool office building, school, hospital or large retail store. Aaah. Now imagine you’ve entered that same building but the air conditioning’s not working. Would you accept that the building’s owners shut it off to be green and consume less energy?

Given that 40% of commercial building utility bills go to power their HVAC systems, manufacturers are placing a strong emphasis on energy efficiency in product design for the rooftop units that move the cool (and hot) air that keeps us comfortable at work, in school, and at play.

Ranging from 3 to 175 tons, rooftop HVAC systems provide a turnkey solution, and can be installed on most large buildings. All components of the system, including fans, compressors, coils, electronics and filters are packed tightly into the unit, making installation, operation, and maintenance as simple as possible.

To meet the energy-saving specifications of HVAC system manufacturers, component suppliers have improved the efficiency and operation of the compressors, motors, fans, gas/electric heating devices and controls inside them.

Within rooftop units, compressors and fan motors consume the most energy. However, both have changed dramatically. Compressors have been transformed from inefficient, single speed devices to variable speed devices with electronic controls, making them 40 percent more efficient than their predecessors.

Similarly, fan motors have evolved from inefficient, single-speed units to variable speed, highly efficient designs. For example, the ebm-papst external rotor EC motor touts an efficiency of 90%.

If you’re responsible for keeping HVAC costs down in your building, this is great news. However, motor and compressor technology is nearing the limits of efficient design. Meanwhile, state and federal minimum energy standards are becoming more stringent.

As the mechanical components within HVAC systems begin to hit their efficiency limits, OEM’s are looking to computer-generated designs that can optimize the heat exchangers and aerodynamics in packaged rooftop systems.

Evolving the heat exchanger
Recent work by the NIST (National Institute of Standards and Technology) is focused on air conditioning heat exchangers.  Using computer generated design and analysis, they produced a unique heat exchanger design that yielded an 8% gain in efficiency for the heat exchanger and a 3% gain in overall unit performance. OEM manufacturers are actively pursuing these ultra-efficient designs. They’re also utilizing materials such as aluminum instead of copper in new heat exchangers to reduce cost and improve efficiency.

Evolving the fan
While current fan motor technology is up to 90% efficient, the blades and impellers within a fan are aerodynamically inefficient. Forward curved fans, used in indoor applications, are about 50% efficient. Axial fans, used in outdoor applications, are between 30 and 40% efficient.

Offering expertise in EC motors and aerodynamic design, ebm-papst is working to boost the efficiency of future products through computer generated design and analysis. We’re also working closely with our OEM partners to test new blade and impeller configurations within rooftop HVAC systems, with the goal of reducing power consumption and lowering operating costs to meet their customers’ needs.  So now imagine being green and keeping the air conditioning on! 

By Matt Menard, Market Manager - Air Conditioning

Building owners view their HVAC system as a necessary evil. Tenants / patients / guests don’t want to hear it or see it, and the system better keep everyone in that building comfortable (an impossible task).  Hot/cold complaints rank #1 on calls into the facilities maintenance department. The HVAC system is the largest utility consumer in a building, mainly due to inefficient motors and compressors. In the eyes of a building owner, the HVAC system should be hidden, silent, efficient and fail-proof.   When the time comes for the HVAC system to be replaced or retrofit, there are many opportunities to improve the system.

These improvements can bring ‘value’ to the building owner in the following ways:  

1.       Energy Savings:  In an average commercial office building, the HVAC system is the largest consumer of electricity, accounting for 40% of the electric bill on an annual basis. Designing and installing an HVAC system that utilizes energy efficient equipment is one of the most logical and effective ways to slash operating costs in a commercial building.  For the past 20+ years, most HVAC manufacturers have put energy efficiency near the top of the R&D priority list developing and utilizing technologies that provide significant improvements in efficiency.  EC technology from ebm-papst is the perfect fit for OEM’s as they strive for higher efficiency, replacing inefficient motors with the most efficient motor technology and integrated speed-control. Many retrofit projects result in energy reduction by 25%, with some extreme cases exceeding 40%.  When combined with government and utility sponsored low-cost financing and rebates for installing efficient systems, building owners will be presented with compelling ROI’s for choosing high-efficiency systems. 

2.       Improved Performance: The hospital of 30 years ago had 1 patient per room and very little technological equipment outside of an X-Ray machine. Today’s hospitals have double the beds, hundreds of computers for the staff, and high-tech tools including CAT & PET scanners and robotic surgical machinery.  All of these changes have one thing in common: they produce enormous amounts of heat.  A 30 year-old HVAC system in a hospital is likely to be undersized and strained, which won’t provide the best environment for the hospital. When a retrofit is performed on the HVAC system, the increased need for cooling capacity and changes to the air distribution system need to be taken into account to create a comfortable and safe environment for all staff and patients The UConn Health Center Bioscience Connecticut facility is being replaced due to inefficient and inadequate mechanical facilities in the existing buildings.    

3.       Better System Control: Even the best and most efficient HVAC systems will operate poorly and inefficiently if not controlled properly.  The ability to control different ‘zones’ within a building allows for the HVAC system to constantly adjust airflow and temperature based on the needs of that zone at any given time. With EC technology from ebm-papst, fan speed can be modulated to provide accurate control and energy savings.  For example, at noon an office cafeteria requires high-volume conditioned air to serve the lunch crowd. At 2:00, all of those people have vacated the cafeteria and are back to their desks, so little airflow is required.  Decreasing fan speed for that zone reduces airflow and the refrigeration system can operate at a lower capacity, both saving energy.  A properly designed and installed automated controls system allows for adjustments to be made in all zones based on time of day, day of the week, current weather, occupancy, etc.  These adjustments and decisions are done automatically and consistently by the computer-based system without the need for human input, keeping all building occupants comfortable at all times in all areas of the building.  In addition to improved comfort, the building automation system can help save enormous amounts of energy as the HVAC system will supply only what is required in specific zones, as opposed to full-blast in all zones at all times. 

4.       Increase in Asset Value: In the commercial real estate market, a building owner’s business is the building. The value of this building can be measured in two ways: revenue generated by the building, and asset value of the building.  Improving any part of the building, including retrofitting the HVAC system with a modern efficient design, increases the value of that asset immediately. In other words, if the building were sold, a premium would be paid for the building with the modern HVAC system than that of the antiquated, inefficient system.  In another case where the building owner retains the property, a modern HVAC system can help with revenue as a premium lease rate can be negotiated due to the efficiency and comfort provided to the tenant. 

5.       Being Green:  Efficient buildings and “Being Green” can bring value to a building owner that cannot be immediately measured in dollars and cents. “Green” and “Sustainability” are very common marketing campaigns being utilized by companies to promote their global citizenship.  Possibly included in these campaigns is the commitment to own/lease buildings that meet certain Green/Energy guidelines. Building owners can take advantage of this market segment with the choices they make in creating energy efficient buildings, and many times charge a premium to clients.

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