Reducing energy costs through high-efficiency chiller system fan motors 

Every year, breweries in the United States spend more than $200 million on energy. That's equal to three to eight percent of the production cost of beer.¹ Faced with competition from larger breweries, microbreweries see narrower profit margins. The cost of energy hits microbreweries even harder. Smaller breweries can consume as much as twice the energy per barrel of finished product as large breweries. For microbreweries, taking energy efficiency measures are an effective way to save money and increase profits.

Breweries and HVAC Energy

Energy usage varies among brewpub operations. Most operators see food preparation and heating, ventilating and air conditioning (HVAC) consuming the most energy. Energy is usually seen as a fixed expense, yet it is a very controllable operating cost. Microbreweries can make prudent, energy efficiency investments to lessen energy costs and consumption. Changes like a space-saving rooftop HVAC system with high efficiency fan motors will not only cut costs but also reduce a facility's carbon footprint.   

Self-Contained HVAC Systems

Self-contained rooftop air conditioning units cool about half of all U.S. commercial space. These packaged units include cooling equipment, air-handling fans, and sometimes gas or electric heating equipment.

There are many ways to  achieve efficiency in rooftop units. Efficiency measures include:

• Adding coil surface
• Applying technologies (such as scroll and twin-single compressors, staging compressors
• Equipping the units with  variable speed advances.

High efficiency fan motors, the heart of HVAC equipment, are also extremely important to rooftop unit efficiency. Most of a rooftop’s power consumption is from the compressor, then the supply and condenser fans. However, HVAC fans often run to provide ventilation even when the compressor is not on. Because of this, the fans can account for up to 45 percent of the equipment’s energy use.

Increasing rooftop unit efficiency will reduce energy use and lower peak usage time. Peak usage is power used during the hours when the energy grid suffers the greatest strain. Lowering peak usage  leads to better facility energy management and also lessens environmental impact.

PMAC Motors

The Permanent Magnetic AC (PMAC) motor is traditionally a more complex construction than the standard induction motor. With the new motor type, powerful permanent magnets simplify the design. The magnets create a constant flux in the air gap. This eliminates the need for rotor windings and brushes normally used for excitation in synchronous motors. With this change, you get the accurate performance of a synchronous motor and the robust design of a standard induction motor. The motor is energized directly on the stator by the variable speed drive.  

HVAC and PMAC Motors

Commercial HVAC retrofits are an example of PMAC benefits. PMAC motors boost efficiency in centrifugally-loaded variable speed applications (pumps, fans and blowers). In many instances, PMAC motors can also direct-drive these designs. Fans are unique because in most cases, they are sized by torque. Direct-driving PMAC motors can eliminate the need for belts, pulleys and sheaves. When you simplify or remove components from power transmission devices, you will see increased service life for the entire drive system. Reduced maintenance is always helpful, especially when a fan is located on a roof. 

In residential and commercial sectors, the highest energy consumers are motor-driven components in HVAC and refrigeration.² In the commercial sector, the two make up 93 percent of motor-driven energy use.³ If you want to reduce staggering energy consumption, HVAC and refrigeration upgrades are an excellent opportunity.

For almost all equipment types in both the residential and commercial sectors, users are transitioning to permanent magnet motors. This technology offers the highest-efficiency models within each category. Permanent magnet motors are becoming increasingly cost-effective based purely on simple payback period. Users see other non-energy benefits like reduced noise and the ability to reach higher rotational speeds.

PMAC Motor Benefits

Standard induction motors are not particularly well suited for low-speed operation. A decline in efficiency accompanies low speed operation. Standard induction motors may also be unable to deliver sufficiently smooth torque across the lower speed range. Normally, a gearbox would overcome this torque issue. The new solution provides a high torque drive coupled directly to the load. Because a user would need to prepare a foundation for one piece of machinery, eliminating the gearbox saves space and installation costs. This also gives more freedom in the layout design. 

The PMAC motor can deliver more power from a smaller unit. For instance, powering the in-drives of a paper machine directly at 220 to 600 r/min with a conventional induction motor would require a motor frame substantially larger than that of a 1500 r/min motor. Using permanent magnet motors also means higher overall efficiency and less maintenance. 

PMAC Achieves Higher Productivity 

Advanced PMAC technology improves system performance. The radial permanent magnetic design minimizes rotor loss, which significantly reduces operating temperature and vibration. Matching a PMAC motor with a variable frequency drive optimizes mechanical systems. The overall effect- maximum output and lowest total cost of operation. After upgrading, most users see a payback in just 12 to 23 months with a noticeable reduction in monthly utility bills. 

PMAC motors provide:

• Higher efficiencies achieved across a speed range
• Greater torque capabilities
• Greater power density
• Lighter than AC induction motors in a comparison within the same HP range.

High Efficiency Chiller Systems and Craft Breweries

Few industries have seen as much growth and evolution in the past 30 years as craft breweries. This growing sector has changed the purchasing and drinking habits of many beer lovers.  What was once the pursuit of hobbyists has become a sector of commercial significance. Energy management has become a major priority for these brewery operators.  Craft brewers have taken a growing interest in sustainability, particularly energy use. As production has increased in scale, energy efficiency has become an important financial consideration for many microbreweries.⁴

The brewing process starts with mixing (or “mashing”) malted barley and other grains with high-temperature water. The resulting liquid, or wort, is drained off of the grains. Brewers then boil the wort while adding hops and (sometimes) other spices. After cooling, the wort is mixed with yeast before fermentation (at a temperature suited to the strain of yeast employed). Once fermentation has ended, cleaned bottles are filled with the resulting beer and packaged for delivery. Some breweries cellar the beer or keep it in cold storage before distribution.⁵

Refrigeration is a necessity in most breweries. Many times, there are separate refrigeration systems operating in a brewery. Refrigeration costs can add up to more than 30 percent of a brewer’s electrical consumption. (6) Considering rising energy costs, addressing factors that affect efficiency, such as the chiller system, can pay big dividends. High torque PMAC fan motors help reduce costs in high efficiency brewery chillers. Even better for those who use them, these systems can sometimes have short payback periods of only two to three years.

The process of heating and cooling the wort is critical to the success of craft beer. Industrial brewing chillers are an efficient way of quickly cooling wort. Additionally, HVAC systems maintain temperatures in brite and fermentation tanks. It is crucial for chillers to operate in a quick and efficient way to lower the wort back to the ideal temperature. 

Conclusion

Today’s craft breweries are making great strides in reducing energy consumption. Implementing the latest technologies and practices increases efficiency and cuts costs. PMAC motors have several advantages over AC motors. PMAC motors  significantly reduce operating temperature and vibration. They also provide higher efficiencies achieved across a speed range, and offer greater torque capabilities and increased power density. Adopting chiller systems with high efficiency PMAC motors helps breweries see savings.  

 

¹ http://www.energystar.gov/ia/business/industry/LBNL-50934.pdf (accessed April 9, 2015).

² https://www.energy.gov/sites/prod/files/2014/02/f8/Motor Energy Savings Potential Report 2013-12-4.pdf(accessed January 10, 2018).

³ Ibid

⁴ https://www.plantengineering.com/articles/gas-technology-craft-brewers-watch-energy-dollars(accessed October 6, 2016).

⁵ https://www.mge.com/saving-energy/business/bea/article_detail.htm?nid=1914 (accessed January 10, 2018).

⁶ https://snopud.bizenergyadvisor.com/microbreweries (accessed January 10, 2018).