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Modular Building Institute

Facility's Upgrades Keep Product Fresh

Nov. 1, 2007
The Anheuser-Busch sales and distribution center in San Angelo, Texas, is part of one of the largest beer wholesalers in the United States. In one year,

The Anheuser-Busch sales and distribution center in San Angelo, Texas, is part of one of the largest beer wholesalers in the United States. In one year, approximately 1 million cases of beer move in and out of the plant, which stores packaged and keg beer.

Anheuser-Busch recently completed a $3 million expansion of the San Angelo facility, adding a 17,000-sq-ft refrigerated package vault and a loading dock. The plant's two existing package vaults each housed two refrigeration units and 20-year-old electronic control panels. The new package vault features four refrigeration units. When Anheuser-Busch wanted state-of-the-art environmental controls for the plant, it called Trend Control Systems.

Anheuser-Busch has strict policies regarding its products and maintaining temperatures for freshness. Multiple temperature fluctuations adversely affect the taste of its product. The company dictates storage-plant set points of 46°F during winter and up to 66°F during summer.

At 1,850 ft above sea level, San Angelo — nicknamed the Shining Star of Texas — enjoys a relatively mild climate, with about 250 days of sunshine. The average monthly temperature is 77°F, with normal highs falling between 58 and 94°F. Meteorological fluctuations outside — combined with 28 massive, constantly turning fans inside — make maintaining precise temperatures inside the plant difficult.

The evaporators, stands, and compressors inside each existing refrigeration unit lacked onboard controls for reporting temperature fluctuations. That meant the operations manager was unaware of straying temperatures until an alarm alerted him. Anheuser-Busch requires constant temperatures — not a tenth of a degree up or down — so the plant's new state-of-the-art controls system had to be unfailing in its operation, monitoring, and alarming.

Another challenge the operations manager faced was avoiding downtime on the compressors. This was most imperative in the keg vaults because, unlike the canned and bottled beer in the package vaults, keg beer is not pasteurized. If one of the two compressors in the San Angelo keg vault goes down, temperatures could climb quickly, risking a great deal of product.

The existing building-controls system was not able to alert the operations manager to operating conditions or any issues that cropped up. As a result, his presence was required at the equipment site to see if it was running correctly and to observe any problems. Having to patrol the 27,000-sq-ft plant on foot and make adjustments manually took too much time and effort.

Anheuser-Busch requires the plant to keep a year's worth of records to make sure temperatures are constant and accurate. The controls system needed sophisticated trending and reporting capabilities to demonstrate the plant's adherence to the company's strict temperature policies.

Ener-Tel, Trend Control Systems' West Texas technology center, installed a Trend system in the San Angelo plant to control and monitor the package vaults. IQ3xcite controllers monitor the refrigeration units, and IQView touchscreen displays provide quick, comprehensive views of all data from the networked controllers. The Trend IQ system also is integrated with exterior lighting controls in the plant's parking lot.

To gauge the actual temperature of product, Ener-Tel simulated the Anheuser-Busch refrigeration units by fabricating copper tubing, filling it with oil, and inserting a temperature sensor inside. Because air is more fluid than liquid, the plant's massive overhead fans, which run 24/7, can cause the temperature inside the package vaults to fluctuate. With accurate temperature readings, the operations manager is able to program the Trend system to maintain precise set points. He can record air and liquid temperatures inside the plant.

The San Angelo plant's operations manager now receives e-mail and text messages for any issue he programs the Trend system to monitor. This includes temperature set points for the refrigeration units and package vaults. If a piece of equipment operates outside established parameters, the system sends an e-mail alarm and text message to the operations manager's cell phone. He then can log into the network with remote access to view the problem.

To comply with Anheuser-Busch's strict reporting protocols, the Trend system polls trendlog data point values every 15 min to monitor and verify system activity and identify critical operating trends inside the package vaults. The operations manager then can view and print the data in graph format or as a comprehensive list of temperature values. He makes notes on the printed copy, identifying and explaining any spikes and the corrective actions he took, and submits the printouts for reporting purposes.

As part of the plant's remodel, Anheuser-Busch replaced its 20-year-old controls with Trend IQ equipment, making the entire plant compatible with the building-automation system (BAS) and networking the devices. This enabled the operations manager to view the entire system from his office — or remotely from his home — without having to walk the floor to identify issues.

Finally, Ener-Tel set up automatic lead/lag so the compressors run only when needed and none operates more than the others. The San Angelo compressors are on a 30-day cycle during which three always lag behind the one currently in operation. In this way, maintenance is fairly equal for all of the compressors. Because automatic lead/lag balances the compressors' run times, none will wear out faster than the others.

Since its installation, the Trend system has maintained temperatures inside the package vaults within 1°F of the required set points at all times — despite the plant's inside temperature changing as much as 10°F from month to month. The Trend system enables the operations manager to view and poll data points at any time interval he chooses so he can view system activity and spot operating trends. He then can use the printed data for his reports.

With the BAS equalizing run times on the compressors with automatic lead/lag switching, the units run only when needed. No unit operates more than another, which simplifies maintenance.

“The biggest difference now is the flexibility and access we have — really seeing more of what's going on,” Mark Tumlinson, operations manager for Standard Sales, the parent company of Anheuser-Busch Distributing, said. “It's not just the quantity of the information; it's the quality of it, too.”

Project Scope

Equipment used in an update of the San Angelo, Texas, Anheuser-Busch distribution plant included:

  • Three IQView touchscreen displays
  • Three IQ3xcite controllers
  • Seven input/output expansion modules
  • Eighty-eight total input/output points
  • Two package vaults, 25 hp each
  • Four package vaults, 15 hp each
  • Two keg vaults, 7 hp each
  • Eight refrigeration units
  • Fourteen temperature sensors