Foodservice Equipment Reports

FER REPORT: "Remote" Possibilities

Remote refrigeration certainly isn’t a new thing. New components have come on the market in recent years, yes. Modern scroll compressors are better and more efficient than conventional reciprocating units. Coils and corrosion protection are more advanced than in the past. The refrigerants themselves have evolved over the years. And parallel rack systems—loosely defined as common components shared by multiple pieces of refrigeration equipment—have become more common. You’ve probably come across these updates as you’ve had to deal with routine replacement.

But when was the last time you reexamined the big picture? Not that you’ll go back and refit existing installations en masse. But going forward, will you keep doing what you’ve always done? 

Why Remote 

Maybe the first question is whether you should remote anything at all, and if so, what. In principle, the plusses for remoting are pretty well known. When located inside the kitchen, compressors generate heat, and condensers expel heat into the environment. Dumping that heat into the workspace is problematic. It makes for an uncomfortable work environment, and the ambient heat becomes a problem for other equipment in the space. Further, all of that heat becomes an additional HVAC load. You pay twice: first to extract the heat from the equipment and then to extract it from the building. There also are maintenance issues.

“One benefit of going to remote components is that they’re easier to service than self-contained units when the restaurant is busy,” says Andy Dunmire, v.p.-design and construction at Eat’n Park, Homestead, Pa. “It’s difficult to put a dollar value on that, but as concepts are squeezing more square footage out of the back of house, it makes servicing without interruption even more difficult.” 

Other payback items: A lot of specifiers loosely assume improved utility efficiency; depending on particulars like extreme climates, the size and number of components being remoted, etc., that often is true. But even bigger advantages can come in performance and reliability of the refrigeration system. Getting components away from the kitchen heat and grease can make a big difference.

Downsides? Remote refrigeration systems add capital expense—by some estimates 25% or more—and complexity. More pieces mean more chances for things to get leaky and strange. The electrical and refrigeration lines are longer. The system needs more refrigerant to fill those longer coolant lines, etc. And climate will play into specs, cost and durability. 

So how do you decide where and how to spend the money on a remote installation? Where’s the payback?

One point to consider, says Dave Entrekin, national technical sales manager, Master-Bilt Refrigeration, New Albany, Miss., is the balance between remote costs and HVAC sizing and operating expenses. Remoting a significant amount of refrigeration will reduce HVAC load, which might let you reduce HVAC sizing, he says. 

Basically, you have to run the numbers. If refrigeration is not a big part of your business, if it’s not a big cost for you, remotely installing components might not be worth the cost and complexity.

“If refrigeration is a big piece of your operating budget, as it is at a c-store or a supermarket, remoting offers proportionally larger benefits and cost savings,” says foodservice engineering consultant John Bowden of The Bowden Group, Ostrander, Ohio. But for smaller operations, the benefits and savings might be less significant. “A facility with a bunch of glass coolers is much different from a small-footprint QSR, for example,” he notes. 

“We sell food for a living,” he continues, and investment in equipment systems needs to be measured against that. “The bigger vision on equipment is whether it’s worth the complexity it adds over the next 20 years,” says Bowden, who has several decades of experience as an equipment specifier in the QSR segment. “Trading one issue for another is not progress. The challenge is people don’t often see all the issues. Purchasing might only see cost. But there’s energy and maintenance to be considered, too.

“When I look at remote refrigeration, the question really is a balance of cost and performance,” Bowden says. “It depends on the individual operator’s perspective on cost vs. the science of performance. 

“Cost, you look at initial and at long term. Under initial cost, you look at the size of the equipment to be refrigerated. On a percentage basis, it is less costly to remote a walk-in than a reach-in. It’s more cost-effective. If you’re looking at smaller equipment, say a 1/3-hp or smaller compressor, it shouldn’t be remoted. It’s a physics problem. You just don’t get the cost-performance payback.”

Another time you might not remote is if your air conditioning is free, he says. If your lease says the owner provides air conditioning, the math on your payback changes. This, somewhat ironically, fits right in with a lot of lease situations. “Many operators occupy rented or leased spaces that prohibit breaching the structure walls or roof,” notes Ben Picker, Copeland product manager, Emerson Climate Technologies, Sydney, Ohio. “This prevents running the refrigerant lines needed for a remote system.” 

Another consideration is noise. If the noise refrigeration equipment generates isn’t a factor—for guests or staff—that’s one less reason to go remote. On the other hand, a noisy icemaker in the dining room is an awful thing.

“And you look at things like the size and configuration of the facility—is it 10 stories or one?” Bowden says. “Given the laws of physics, what will it take to make it work?” It’s important to note that technology in remote refrigeration makes almost anything possible, but whether lengthy vertical or horizontal runs are practical or cost-effective may be another matter. 

For most foodservice operations, at 2, 3 or 5 hp each, walk-ins are the biggest refrigerated pieces, so they’re the first candidates for remote components. Next come ice machines. Prep tables and reach-ins probably aren’t candidates. If all you’ve got is the walk-in, you might not want the expense of remoting. You can just outfit it with a package that mounts atop the walk-in, which might put it beneath the building’s ceiling or might extend above the ceiling line, depending on the walk-in height vs. the building ceiling.

If you have multiple walk-ins, ice machines and so on, you might remote them each separately with their own compressors and condensers up on the roof or out on a concrete pad by the side of the building. Or you can save some capital cost, complexity and energy by piggybacking multiple components on a single rack system. 

Parallel Racks For Select Few 

Parallel rack systems, another refrigeration technology that’s been big in supermarkets for a while, are making some inroads now in larger foodservice installations, but the emphasis remains on larger ops. Parallel rack systems come in a few different configurations. Mostly they involve running multiple refrigeration pieces to a remote rack housing a single condenser and multiple compressors. In some designs, a single “main” compressor does most of the work, and when loads rise, additional compressors kick in to augment the main compressor. In other designs, multiple compressors share the load and ramp up and down together. Larger operations might need larger parallel racks. If you have 12-15 refrigerated pieces of equipment, you might have a single huge rack with three or four condensers and a half-dozen compressors. Or you might have multiple parallel racks. But examples this big would be few and far between in foodservice. 

One of the main items when considering parallel systems is redundancy. What if the condenser or one of the compressors fails? Which refrigeration equipment is tied to which components? Give that some thought. Guard yourself against single-point failures that would bring down refrigeration in your key cold-storage equipment.

Skilled maintenance and repair support is another thing to plan for. “Parallel racks are not usually serviced by your regular refrigeration tech in foodservice,” says Jack Heisler, service manager at Allegheny Refrigeration Service Co., Pittsburgh, Pa. Bowden makes the same point, noting there’s often little crossover between supermarket servicers and foodservice servicers, so you might have to search around. 

New Components, New Designs 

As mentioned previously, once you sort what equipment you might want to route to remote components, you’ll be looking at components that work better than their predecessors. You’ll want to consider scroll compressors, which started out, like most things, in bigger applications but now are available in smaller, more useful sizes for foodservice applications. Scrolls have fewer moving parts than conventional hermetic reciprocating compressors, offering increased reliability and reduced noise, and the scrolling/turning motion is inherently more efficient than the reciprocating movement of traditional compressors. The advantage in energy savings can be 20% or more. Couple scrolls with other higher-efficiency components—variable-speed condenser fan motors, digital controls, etc.—and the cumulative efficiency gains can be significant. 

Condenser coils are better these days and can be more corrosion-resistant as well. Look for aluminum as opposed to traditional copper alloys. Many suppliers offer a coated version of aluminum to further resist corrosion especially in coastal areas, and in most climates you’d be hard pressed to turn down the coatings (salt air plays havoc on uncoated aluminum). 

You might want to delve into the finer points of refrigeration components, as well. Heatcraft Worldwide Refrigeration, Stone Mountain, Ga., for example, touts a microchannel coil design that uses less refrigerant and provides superior leak and corrosion resistance to traditional coils, according to Jeff Johnson, Heatcraft segment manager-food service. Johnson says the design makes the condenser coil lighter and easier to clean as well. 

Be sure to consider refrigerants. R-404A and R-134A are still the most common coolants for anything but the smallest applications, but they’re not the only ones. Johnson notes that glycol systems, first seen in larger installations like supermarkets, for example, are appearing in foodservice applications. Master-Bilt Refrigeration, for example, is marketing a glycol-and-R-404A system. “Glycol is a very effective heat-transfer fluid,” Entrekin notes. In the Master-Bilt system, glycol cools the equipment and then circulates to a brazed-plate heat exchanger in the rack system, where R-404A takes the heat out of the glycol. The evaporator then absorbs the heat from the R-404A. Among the advantages to this system, Entrekin says, is reduced refrigerant volume, less refrigerant piping and reduced risk of refrigerant leaks. With glycol, piping is a choice of copper or less-expensive ABS plastic. Advanced digital controls and variable-speed glycol pumps are said to reduce energy consumption by as much as 25% as well. 

Sizing Matters—So Does Maintenance 

Whichever way you go, refrigeration systems are spec-sensitive, and everyone we spoke with says you have to think it through carefully. “One common mistake is basing decisions too much on initial cost,” says Scott Hester, v.p., Refrigerated Specialist Inc., Mesquite, Texas. “I’ve seen a lot of operators go with self-contained systems, and then they have the wrong environment, and they’re not happy.” Wrong environments feature a host of problems, such as kitchens that are too hot, heat sources that are too close to each other, intake air that is too grease laden and workspaces that leave no room for basic chores, like cleaning condenser coils. 

“Errors on the remote side are commonly capacity related,” he continues. “Operators may put too much capacity onto the roof system, too much horsepower. And then if there’s not enough load, the large compressors don’t work properly.” Excessive cooling capacity often can shorten run times, which can lead to more frequent start-stops. That, in turn, can increase wear on electrical and compressor components. Other symptoms of overcapacity can include too-low suction pressure, which can lead to hot running temps that shorten lifecycle. Too much cooling also can cause icing on the evaporator side of the system, which ironically hampers airflow and cooling in the walk-in. Conversely, of course, too much load creates the opposite problems with overworking components and premature wear. It’s all a delicate balancing act. 

Load, remember, includes many factors. How many pieces of equipment are you running through the remote system? Walk-ins, multiple walk-ins, icemakers, prep tables, salad tables and display cases all add up. What’s your ambient workspace temperature? What season is it? “Say we had a capacity problem during fall or spring,” Hester says. “Now the Texas summer comes, and the system runs 24 hours a day and cannot keep up. Refrigeration and air-conditioning calculations generally are based on average run times and operating 14-18 hours a day of average temperatures. Then in a heat wave you run longer hours, and in winter you run shorter.” 

But not too short, Hester cautions. If the system doesn’t run at least 10 hours a day, essentially you have an overcapacity unit and you will start running into the overcapacity problems mentioned previously. 

For all of those variables, Hester says it’s important to deal with a refrigeration expert who has experience and knows his or her way around a commercial kitchen. Hester adds that sometimes you can just look at the data and do the math, but you still need someone with experience to know whether to go one size up or one size down from the size a computer calculation indicates you need. 

Bowden makes similar points. “Phoenix and Minnesota are much tougher on remote refrigeration than the Carolinas. In a hot environment, you need more condensing surface. In Phoenix, ambient temps can be 120°F, and rooftop readings can be 140°F or higher, and I’m trying to eject heat into that? It’s physics. It ‘works,’ yeah. But at half the effectiveness, and the system lasts half as long. 

“In Minnesota, a remote system can work, although a small unit might not generate enough heat to work well. You can deal with extreme climates, but they add cost.”

Coming Soon

What’s the crystal ball saying? More choices to come in refrigerants and controls. “The current trends are revolving around natural refrigerants like CO2 and propane R-290,” Picker says. “While some major chains are leaning toward either one of these natural options, new refrigerants that should become available soon may make more economic sense than the natural refrigerants, while remaining environmentally friendly.” 

Other trends, he says, revolve around creating smarter systems. “With a need to reduce energy and ensure food safety, electronics are becoming ever more important. Smart systems can monitor the operation of each piece of equipment and determine if service is needed before the system breaks down. If service is needed, the system can provide diagnostic information to the technician, ensuring the problem is corrected quickly and accurately.” Advance warning can save your inventory and keep your operation open.

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