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Microbreweries Tapping into Savings

Reducing energy costs through high-efficiency chiller system fan motors

Annually, breweries in the United States spend over $200 million on energy, which is equal to three to eight percent of beer’s production costs.¹ Surprisingly, however, microbreweries can consume as much as twice the energy per barrel of finished product as large breweries and typically have narrow profit margins; making energy-efficiency measures a particularly effective way to save money and increase profits.

Breweries and HVAC Energy

Energy usage varies among brewpub operations; however, food preparation and heating, ventilating and air conditioning (HVAC) consume the greatest amount of energy. Typically, energy is viewed as a fixed expense, yet, it is a very controllable operating cost. With prudent, energy efficiency investments, such as space-saving roof top HVAC systems with high efficiency fan motors, breweries are able to lessen energy costs and consumption while reducing their carbon footprint.

Self-Contained HVAC Systems

About half of all U.S. commercial space is cooled by self-contained, packaged air conditioning units that sit on rooftops. These self-contained packaged units, including cooling equipment, air-handling fans, and also sometimes gas or electric heating equipment, are found on the tops of buildings.

There are a number of ways to achieve efficiency in rooftop units, from adding coil surface to applying the latest compressor technologies, such as scroll and twin-single compressors, staging compressors, or equipping them with variable speed advances.

Highly efficient 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, because the fans often run to provide ventilation even when the compressor isn’t running, they can account for up to 45 percent of the equipment’s energy use.

Increasing rooftop unit efficiency not only reduces energy use, but also lowers peak usage time, which is power used during the hours when the energy grid suffers the greatest strain. Lower peak usage supports better energy management for the facility and also lessens environmental impact.

PMAC Motors

The PMAC motor is traditionally a more complex construction than the standard induction motor. With the new motor type, the design has been simplified by using powerful permanent magnets to create a constant flux in the air gap, thereby eliminating the need for the rotor windings and brushes normally used for excitation in synchronous motors. This results in the accurate performance of a synchronous motor, combined with 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

One example of PMAC benefits can be found in commercial HVAC retrofits. In centrifugally-loaded variable speed applications (pumps, fans and blowers), PMAC motors boost efficiency — and, in many instances, can direct-drive these designs. Fans are unique in that they are typically sized by torque; yet direct-driving PMAC motors can eliminate the need for belts, pulleys and sheaves. With power transmission devices like gear reducers simplified or removed, you will see increased service life of the entire drive system. Reduced maintenance is particularly helpful where fans are installed on roofs.

Motor-driven components used in HVAC and refrigeration are the highest energy consumers in both the residential and commercial sectors.² In the commercial sector, the HVAC and refrigeration categories combined account for 93 percent of motor-driven energy use.³ Clearly, these applications offer an excellent opportunity for reducing staggering energy consumption.

For almost all equipment types in both the residential and commercial sectors, users are transitioning to permanent magnet motor technology for the highest-efficiency models within each category. Permanent magnet motors are becoming increasingly cost-effective based purely on simple payback period. They also offer other non-energy benefits such as 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 as their efficiency drops with the reduction in speed. They may also be unable to deliver sufficiently smooth torque across the lower speed range. This is normally overcome by using a gearbox. The new solution provides a high torque drive coupled directly to the load. By eliminating the gearbox, the user saves space and installation costs, as he only needs to prepare the foundations for one piece of machinery. 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 with a radial permanent magnetic design that minimizes rotor loss, significantly reducing operating temperature and vibration. When a PMAC motor is matched with a variable frequency drive, the combination helps optimize mechanical systems to achieve maximum output and lowest total cost of operation. Upgrading to a PMAC motor typically delivers 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 of the brewing industry has changed the purchasing and drinking habits of many beer lovers. Energy management has become a major priority for these brewery operators. As they’ve grown from hobbyist scale to commercial significance, craft brewers have taken a growing interest in sustainability, particularly in terms of energy use. As production has increased in scale, energy efficiency has also become a more important financial consideration.⁴

In general, the brewing process involves mixing (or “mashing”) malted barley and other grains with high-temperature water; draining the resulting liquid, or wort, off of the grains; boiling the wort while adding hops and (optionally) other spices; cooling the wort; then adding yeast and letting the mixture ferment at a temperature suited to the strain of yeast employed. Once the wort has fermented, bottles are cleaned and filled with the resulting beer and packaged for delivery. Depending on the brewery, beer may be cellared or kept 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 With energy prices already high and continuing to rise, paying attention to factors that affect efficiency, such as the chiller system, can pay big dividends. High efficiency brewery chillers with PMAC fan motors that provide higher torque help reduce energy costs and can sometimes have fairly short payback periods of only two to three years.

Industrial brewing chillers are an efficient way of quickly cooling wort as well as maintaining temperatures in brite and fermentation tanks. The process of heating and cooling the wort is critical to the success of craft beer and it is crucial that the chiller operates quickly and efficiently to lower the wort back to the ideal temperature.

Conclusion

Today’s craft breweries are making great strides in reducing their energy consumption and costs, and in implementing the latest technologies and practices for efficiencies. One way to achieve this is through the use of chiller systems that utilize high efficient PMAC motors. These motors, in comparison to AC motors, significantly reduce operating temperature and vibration, provide higher efficiencies achieved across a speed range, and offer greater torque capabilities and increased power density.