Ice machines are a paradoxical bunch. They can be the forgotten workhorse in a kitchen and often come in last on equipment purchasing priorities. But at the same time, they open up incredible opportunities for total-kitchen energy savings because of their improved efficiencies.
"There has been an advent in improved ice harvesting and other technologies over the past five years," says Ray Soucie, FCSI, LEED AP, principal of RSA Inc. Foodservice Design in Portland, Ore. "Some models now use 50 percent less water and significantly less energy than ever before."
Don Fisher, co-owner, Fisher-Nickel, Inc., and operator of the PG&E Food Service Technology Center in San Ramon, Calif., shares a similar perspective. "Ice machines are kind of off the radar when it comes to energy-saving equipment," he says. "In actuality, ice machines are major energy-using pieces of equipment. So the potential for total kitchen energy savings by selecting the right model is quite significant."
The first step in sustainable ice machine selection, according to Fisher, is to research the energy usage of different brands and models on the Air-Conditioning, Heating and Refrigeration Institute website at www.ahrinet.org. "Their data is incredibly thorough and useful, and we (the Food Service Technology Center) support their test results," Fisher says. Users of the site can select by manufacturer, unit size and ice-making capacity to compare the maximum kilowatt per hour used by the different brands on the market. Access the directory here.
Beyond selecting a machine based on energy efficiency labels and test scores alone, maximizing the efficiency involves several other measures: first, it's crucial to match the capacity of the machine with the needs of the operator/end-user. Otherwise you risk producing too much ice, which could lead to waste, or produce too little at a time, which could cause the machine to expend more energy to produce the desired amount. Choosing the right type of condensing unit for an operation also presents an important challenge, Fisher says.
Water-Cooled vs. Air-Cooled Machines
Once the more prevalent type of ice machine, water-cooled units (without the use of closed water loop systems) are slowly being phased out of demand because of their significant water usage; they flush fresh water down the drain, essentially, according to Fisher. However, hotels and other large institutions with closed water loop systems can easily support these types of units without wasting too much chilled, fresh water. In terms of energy usage, "In this case, they can be as efficient as an air-cooled machine," Fisher says.
Air-cooled machines tend to run about the same as water-cooled machines in terms of energy efficiency, Fisher says, but they still save more water than water-cooled units, even if closed loop systems recycle water. According to Soucie, air-cooled ice machines can also pose an advantage for projects pursuing LEED status, where total building water conservation can lead to extra points.
Even still, new LEED prerequisites for water consumption stand at higher rates than ever before, Soucie says. "When you use more water, you pay for it three times," he adds. "You pay for it coming in, when you use it and when it goes down the drain in sewer charges."
Smaller restaurants face a dilemma when it comes to air-cooled machines, however. "You can't have a self-contained air-cooled unit sit on top of a soda machine pumping heat into the front-of-the-house area," says Armand Iaia, regional manager for Cini-Little International, Inc. While this setup might be acceptable in larger, open-air buildings and facilities like stadiums or large serveries with sophisticated venting capabilities, in smaller, enclosed areas, self-contained air-cooled machines force ventilation systems to work much harder.
Air-cooled machines with remote condensers can be an ideal solution in terms of energy and water efficiency. Still, these systems have their own drawbacks. Take the desert, Soucie says, where all day long the sun would beat down on a remote condenser placed outdoors, perhaps on a rooftop. In that case, "Closed-loop water cooled units are most effective in hot climates such as Las Vegas, where the outside air temperature could adversely affect the remote condenser," he says. Remote units and water-cooled units also work best in space-constrained, mechanical mezzanines where indoor venting is not an option, Soucie says.
In addition, remote condensing can be an expensive venture for smaller restaurants. When it comes to big cities with taller buildings, rooftop condensing can pose both design and financial burdens.
What's also challenging about remote condensing in particular, Fisher says, is "we don't have data to show how much you can save when you use a remote condenser versus a self-contained unit or ice-making head." While the assumption is that remote condensing saves on total building energy use because of the lessened strain on the HVAC unit, that data does not exist at the moment because of the complex variations between each remote condensing environment. This could cause a problem for schools and other institutions needing to justify the extra cost for the equipment.
Still, if it's possible to condense remotely, it's the best option, Soucie says. "You pay more upfront for installation but the potential for a quicker return on investment is higher," he says.
In addition to remote condensing and closed water loop systems, Iaia has worked with operators to tap into existing geothermal water loops to cut down both on energy and water usage with ice machines. "With schools you have to be careful with this setup because the geothermal has to be running the whole year," he says. "If you shut down the geothermal unit the refrigeration will go off."
Sometimes the only viable option is a self-contained air-cooled unit, Iaia says. In that case, positioning the unit appropriately (i.e., not placing this type of ice machine near the salad bar) can cut down on the rejected air funneling into the main kitchen or dining space.
Newer models offer unique alternatives to remote condensers for operations with limited space. One manufacturer, Soucie points out, recently released a model that uses an auger, or corkscrew-type design to push out ice through a tube as it turns. Unlike a traditional ice machine, which freezes water on a plate, the corkscrew option comes with fewer moving parts, which reduces energy consumption by up to 50 percent. The tube can also be extended up to 75 feet beyond the ice dispensing location to act like a remote condenser. Both the corkscrew design and extended tube help prevent the machine from expelling hot air and energy close to the dispensing area and ice bin. The ice bin could theoretically sit out in the front of the house or in an open space with the tube running behind a wall in the back room.
Specify Slightly Larger, Not Smaller
It seems counterintuitive, but specifying larger machines instead of multiple smaller machines often saves more energy, even if the machine produces slightly more ice than needed or requires a bit more labor to transport the ice.
"Many of the 500-pound ice machines have the same components — or better — as the 400-pound machines," Fisher notes. So with just a 100-pound difference, the machine may actually work harder in less time, the definition of efficiency. "Ice machines really are energy guzzlers. So if you go for two 200-pound machines you could end up using twice the energy of one 600-pound machine to meet your ice-making needs. You really have to go back to looking at the KWH used per 100 pounds of ice for the different machines out there."
Also consider labor and the distance the ice has to travel, Soucie says. Evaluate the tradeoff between using multiple machines to save on the distance the ice has to travel before it is used versus a single hardworking machine and an extra pair of hands. Newer models dump ice from the bottom of the machine, which cuts back on scooping labor and ensures better food safety, meaning there is less potential for hand-scooping or using glass to scoop ice. In that case, the machine takes care of the extra labor required through its capacity.
Multiple ice machines may be necessary, however, if an operation requires different types of ice, Soucie says. A specialty cube machine might be used for cocktails in the bar area while a larger nugget ice machine might sit in back for soft drinks and other utility ice needs.
That said, consider the specific application for the type of ice machine selected, Soucie says. You wouldn't necessarily have to choose perfectly shaped cube ice just for soft drinks and tap water. At the same time, you wouldn't choose nugget ice for hand-crafted cocktails; while nugget ice machines tend to use less energy because they contain more water than perfectly frozen cube ice, they're not quite as pure, Soucie notes. With a faster melting time, nugget ice would easily water down a nice cocktail.
"It's important not to downgrade the quality and type of ice you need for the sake of energy savings," Soucie says.
Running on Time
Many ice machines now come equipped with programmable controls or time clocks to run the machine overnight, rather than during peak energy-use hours, such as the middle of the afternoon when it's hotter outside, Fisher says.
"For a little 400-pound machine we were able to help one operator save 34 percent more energy and $500 a year just by running the machine overnight," Fisher says. He also points out that number would only increase with larger or multiple ice machines and this figure didn't even include energy savings from remote condensing.
Even though time clocks are a neglected area when it comes to the technological advancements of ice machines, the potential for dramatic utility and operator cost savings are there, according to Fisher. "We're on a campaign to encourage manufacturers and operators to see the benefits of these controls." One of the current setbacks with time clocks is that some models shut off the machine before dumping the ice, leaving the foodservice operator with a bucket full of melting ice. The best machines with built in timers finish the entire cycle before shutting down.
While non-peak-period programming is a nice feature, Soucie says, "You have to make sure you keep track of the programming. If a seasonal operator were to shut down the machine for evenings and weekends in the winter and crank it up in the summer, you need to make sure the programs are set correctly to make the amount of ice you need. Sometimes it is better to have a larger bin or a backup bin with ice during peak periods than to have less ice."
Some ice machine manufacturers have on-and-off cycling features. Another comes equipped with an electronic monitoring system for online electronic diagnosis. And then there is another brand that senses the thickness of the ice to accurately detect when to harvest. "Many ice machines these days come with smart controls that help in energy conservation," Soucie says.
Outside of specifying the right size, capacity and condensing type, simple add-ons and good preventative maintenance will help prolong the life of the machine and save energy over time, Soucie says.
A simple heat exchanger can be hooked up to an ice machine to reuse chilled drain water off the ice bin and pre-chills the incoming water. This reduces the time the unit takes to freeze the water and helps the condenser run for a shorter period of time," Soucie says. "What's nice is a heat exchanger can be retrofitted on any brand and it doesn't have any moving parts. You can hook it right up to the plumbing line."
Just like a car runs better when fine-tuned, "regular seasonal maintenance is really important for getting better performance," Soucie says. "Many new models have automated cleaning systems." Outside of regular cleaning and maintenance, be weary of placing a machine too close to a bread-baking station or oven, which could cause airborne yeast to invade the machine.
Easy fixes like these can offset limited budgets or buy some energy before it's time to replace the ice machine.