• Refrigeration Controls: The Power of Electronics

    Jan. 1, 2007
    You dont have to be there to be there. Thats one way to describe a key benefit of electronic refrigeration monitoring systems. The ability to conduct

    You don’t have to “be there” to be there.
    That’s one way to describe a key benefit of electronic refrigeration monitoring systems.
    “The ability to conduct off-site monitoring” was the most popular response by refrigeration contractors interviewed by Contracting Business on the state-of-the-art in refrigeration controls. Electronics, say these leading contractors, have greatly influenced the way they service their customers’ systems.
    Because they have transformed so many aspects of refrigeration, Bill Way, manager of automation and special projects for Hughes Environmental Engineering, Montvale, NJ, says electronic controls are the biggest step in the refrigeration business in the last 40 years.
    “Electronic controls are so accurate, you can design the system to do anything you want it to do, from reading pressures and temperatures, to sending alarms to pagers,” says Way.
    “They’re the ‘perfect’ service tool. I can diagnose 50% of the problems on a site before the technician ever goes to the job.”
    Among Hughes Environmental Engineering’s responsibilities is the service of the refrigeration systems for the 400,000 sq.ft. New Fulton Fish Market, Bronx, NY, the Hunts Point Cooperative Market, and the Hunts Point Meat Market.
    “We have 50 to 70 large sites that we’ve installed or taken over. Therefore, shorter diagnostic time adds up to many hours saved each year,” says Way.
    “Our technicians appreciate the technology, too. We have about 50 technicians, four of whom are primarily doing control work, and they love the work.”
    Way says he continues to be impressed by the energy savings made possible by electronic refrigeration controls.
    “We do a lot of peak demand limiting (reducing a building’s energy demand during periods of the day that are traditionally high-use), and when you have many induction motors, you don’t want them all starting and stopping at once.”
    As a service supervisor for a leading refrigeration contractor in Madisonville, LA, Wayne Galiano used a variety of monitors, such as the Beacon II system from Heatcraft Refrigeration Products. The Beacon II monitors room temperatures, checks system status, and makes adjustments at the facility or offsite, through a computer or modem. The system helps maintain consistent temperatures at all times, which improves food quality and energy efficiency.
    “It uses full electronics to convert pressure readings to electronic information, and it self-adjusts to superheat,” says Galiano.
    The specialists at Cooling Equipment Service, Inc., Elk Grove Village, IL, build their own custom controls that allow for complete control of refrigeration systems over the Internet.
    “Customers are beginning to realize how important it is,” says Axelrod. “One of our customers told us remote monitoring helps him sleep at night because he knows the refrigeration information is constantly monitored, and that his systems maintain desired temperatures.”
    Ease of Programming, Precise Temp Control
    Bob Eck, president of Eck Refrigeration, Sidney, OH, is among those refrigeration contractors who appreciate refrigeration systems that are easy to program, and which maintain super-steady temperatures.
    “The one we’ve been using most is the Einstein E2 from Computer Process Controls (CPC). It comes in three models: refrigeration rack controller (RX), convenience store controller (CX), and building HVAC controller (BX),” Eck explains. “The electronic systems don’t experience temperature drift. If the temperature doesn’t drift, it’s easier to control. In addition to precision, the ability to use the controls in a wide variety of applications eliminates the need to stock multiple product lines.”
    Eck uses Paragon defrost timers, White-Rodgers thermostats, Emerson’s Control Techniques variable frequency drives, and step motor valves (ESVs) from Emerson Climate Technologies Flow Controls, to control refrigerant flow.
    “Steppers provide more precise control than standard TXVs,” says Eck. “Flow Controls’ electronic suction regulator valve (ESR) is also an improvement over the old manual type.”
    Eck also uses the CPC IRLDS infrared leak detection device, that he says was very easy to set up and program, and has been trouble-free for three years.
    “System diagnostics is much easier when we can get easy access to large amounts of data,” Eck says. “The more information we can learn about the system when the customer is not there, the easier it is to find and correct system problems.”
    Supply Chain Benefits
    “Electronics bring more efficient energy use, and allows for more diversity in products contractors carry. Now, he has something on his truck that performs multiple functions,” says John Albritton, president of The John Albritton Co., a manufacturers’ representative based in Laguna Beach, CA.
    “That versatility also applies to thermostats with multiple uses, and it all combines to save the contractor time and money,” says Albritton.
    “Wholesalers, too, would rather have less product on their shelves. Instead of stocking 30 different types of defrost controls, they can stock one or two. Overall, we’re seeing more diversified electronic controls in refrigerated cases, instead of systems built with a variety of components.”
    Tim Dehardt, construction manager for the New Jersey branch of AAA Refrigeration, Bronx, NY, also uses CPC’s E2, to control a variety of supermarket functions beyond refrigeration.
    “With the Einstein, we can control humidity, parking lot lights, monitor how long ovens are running, how long the lights are on, anything that uses electricity can be controlled or monitored. It also provides total site management of energy use in any area.”
    “If I get a call that a store has recorded a system alarm, I can get into the store system via computer, determine the nature of the problem, and sometimes correct it from here. If, for example, the alarm is caused by a bad sensor, I can cancel the alarm, and send someone out the next morning.”
    “The amount of information that’s available [via Internet-based systems] is incredible,” says Ron Dehardt, branch manager for AAA’s New Jersey division.
    “You can literally tell if the filters are dirty, or if the fans are running. You can get an alarm call anytime, day or night, and that benefits the retail market, and the consumer,” Dehardt says.
    “Product loss prevention has been cut dramatically, because we can respond a lot earlier than we ever could before.”
    Ethernet a Communications Breakthrough
    Todd Hedenstrom, manager of automation for ALTA Refrigeration, Inc., Peachtree City, GA, says the introduction of ethernet — frame-based technology for local area networks (LANs) — into the industrial refrigeration control environment has led to vastly improved communications and control capabilities.
    ALTA specializes in central refrigeration systems, spiral freezers and rooftop units.
    “We’ve been using Opto IO systems for more than 20 years. We just made the transition from their serial communications products to ethernet,” Hedenstrom says.
    “Ethernet is faster, and has a high data reliability rate. Because of the way ethernet is designed, it takes care of issues I always had to deal with in my programming.”
    Conservative Use of VSDs
    Hedenstrom sees more demand for variable speed drives, however, he urges contractors to consider each application carefully.
    “It has to do with efficiency,” says Hedenstrom. “As a contractor, our philosophy is to run the system as hard as you possibly can to get it cold, and let it cycle, because the best energy savings are obtained when it’s not running it at all.
    “If you run a compressor at half of its capacity, its energy efficiency is down to about 10%, not half. It’s designed run at 100%, but when you start unloading it, and use it at a lower design capacity, its energy efficiency goes off the low end of the scale.
    “There’s definitely a place for variable speed drives,” Hedenstrom says. “When customers tell me about variable speed drives, and ask for it, we give our recommendations. You’re driven by what the customer wants.”
    Over the last couple of years, Hedenstrom has been using programmable logic controllers (PLCs) for a variety of automation needs. PLCs perform simple logic, timing, counting, and real-time clock operations. PLCs read limit switches, temperature indicators, and the positions of complex positioning systems.
    On the actuator side, PLCs operate electric motors, pneumatic or hydraulic cylinders or diaphragms, magnetic relays, or solenoids.
    “With five or six outputs, the best application for PLCs is to replace timers,” says Hedenstrom.