Refrigeration Retrofit Creates Energy Savings On Tap
Advance Beverage's business relies heavily on its warehousing facilities. Distribution means far more than the delivery of product - it means the proper warehousing of these beverages to maintain the integrity and packaging of the product especially with regard to precise temperature and environmental control.
Trouble BrewingFreshness upon delivery, in fact, is so important that Advance Beverage was at a point when an update to their entire refrigeration system to keep their 500,000-plus cases of beverages cool was absolutely necessary. Oxygen, heat, and time are the primary contributors to decreased freshness in beer. During the summer months, temperatures in the Advance Beverage warehouse were rising above Anheuser-Busch's storage requirements. The pre-existing system was inefficient, high-maintenance, and consumed excessive energy. Three refrigerated warehouse rooms were being cooled with 14 air-cooled condensing units on the roof, for a total of 400-compressor hp. Medium-profile DX unit coolers were located throughout the warehouses to provide additional refrigeration.
What made the project the most challenging is that because of local climate, Advance Beverage was faced with the need to raise or lower the setpoint - as many as six times yearly. In addition, they needed to move their existing 400-hp refrigeration system off the roof and into a mechanical room in order to lower maintenance and energy costs.
In 2001, Advance Beverage sought the assistance of Greg Friesen and George Hernandez, Jr., of ARC Comfort Systems, to design a retrofit solution to include managing energy consumption, long-term maintenance costs, and overall cost.
The plan was to replace the existing system with a 250-hp built-up unit in a designated machine room. The new 250-hp system includes Carrier 5H80 and 5H120 compressors, an Imeco evaporative condenser, six Krack AHUs, and uses R-22 refrigerant.
Additionally, a new Teletrol controls system was added. One Teletrol Integrator 486 controller panel with 75 additional points of ValuTRAC I/O was installed with Yaskawa VFDs (supplied by Omron) on the compressors, AHUs, and other equipment. A PC workstation running Teletrol's MCP software was designed to monitor and control the entire system, and was a big part of ARC's success with this project.
Special algorithms were written to control temperature, which allowed ARC a unique approach to this retrofit. The system was programmed to manage setpoint and the alarming threshold through the controls system, along with the ability to control speed, temperature, and defrost, although not monitoring energy consumption directly.
Hernandez said that despite facing the challenge of having to maintain a beer-friendly temperature throughout the warehouse, the installation went relatively smoothly. "We couldn't afford a lot of downtime because it's an active facility, so we had to do it incrementally," he said. Before the flexible duct could be installed, the old coils, drains, and piping had to be removed. This meant moving large numbers of inventory to accommodate the installation of air handlers, drains, and plumbing, while building and loading 30 sales trucks per day.
47% SavingsAn independent vendor was brought in to record system energy usage prior to the retrofit, and remonitor the system afterward to measure energy savings. The monitoring showed that the new variable-speed system saved 47% of the total energy used for refrigeration, as compared to the previous constant-speed air-cooled system.
With the project complete in December of 2001, Scott Barnett, chief financial officer of Advance Beverage, stated, "Our latest electrical billing for the month ending June 2002 shows a reduction in kilowatt-hours per day of 33.7% compared to the same period last year." It's estimated that the portion of the project's electricity consumption related to the refrigeration system is between 75% and 80% of their total consumption. This means that the consumption reduction related to the retrofit is between 42% and 45% when compared to the previous system.
Advance Beverage also received great benefit from the variable-speed motors and the water-cooled evaporator tower (also installed in the retrofit) during the summer months. Additionally, the actual power costs are lower than last year, even after a large electric rate increase, due to a large reduction in peak period usage which carries a $0.10/kWh surcharge on their rate schedule. "After one year of operating the new system with no problems - only normal maintenance -we have crisp, clean, temperature-efficient rooms, and have exceeded our expectations of energy savings," said Jerry Mason, the company's operations manager.ES