In the textbook, Refrigeration & Air Conditioning Technology by Bill Whitman, Bill Johnson, John Tomczyk, and Eugene Silberstein, the authors wrote, “When the service technician arrives at the job, it may be necessary to evaluate whether a particular evaporator is performing properly. This can be considered one of the starting points in organized troubleshooting.”
It just so happens that the starting point typically is configured with tubes and fins that allow the evaporator to absorb the heat so the compressor can pump the heat and the condenser can reject it. And, as students-turned-technicians know, there are a number of coil configurations and technologies morphing with the times.
The NEWS asked a few individuals at a recent refrigeration trade expo — and a few others in the industry — to do a bit of fortune telling regarding what the next generation of coils may look like.
Brian Baker, owner of CustomVac Ltd. in Winnipeg, Manitoba, Canada, said, “I do think we will see coils that move away from traditional, A-style coils to M-type coils, which allow lower pressure drops and more coil surfaces. In my climate area, the sensible loads are low, and latent loads higher, which has been driven by tighter structures. In fact, this is why in the last 25 years our ductless market grew and exploded. Variable capacity and yet comfort; it is complex, but they need to get the microchannel sorted out.”
And that microchannel sorting out is taking place. Steven Wand, president and CEO of AlCoil, said, “Microchannel coils, like scroll compressors and other HVAC components, have made great strides. We know their use is growing and will become the predominant airside coil of choice due to reliability, energy efficiency, lower refrigerant charge, and cost. Long-term, field technicians should see more use and higher reliability as more OEMs integrate all-aluminum microchannel coils into their equipment.”
And there are more developments on the horizon, said Dave Anderson, vice president of sales and marketing for Luvata Heat Transfer Solutions. “The next-generation coils are available with alternate materials, alloys, and coatings to further reduce the risk of formicary corrosion,” he said. “We’ll continue to see a reduction in tube diameters as well as increased use of natural refrigerants such as ammonia and CO2 that may require heavier tube construction.
“Included in the environmentally friendly refrigerants are hydrocarbons (HCs). They are highly flammable with the right air-fuel ratio, therefore it is even more important the industry takes extra precautions to prevent refrigeration system leaks. Current regulations limit the amount of HCs in refrigeration systems. The smaller-diameter tube coils reduces the internal volume, using less refrigerant in the system,” he said. “Environmentally friendly refrigerants come with special handling instructions. Additionally, the units will become more complex, and, in turn, the proper training of installing contractors and service technicians will become increasingly more important with next-generation coils.”
For Tim Fregeau, sales manager, Apex Engineering Products Corp., the learning curve continues. “Contractors have to be educated not only on the new designs and alloys of coils, but also the cleaning products on the market to help maintain these coils. There are hundreds of coil cleaners and pieces of equipment on the market, each made to be used on different alloys and materials. It is up to the contractor to learn which products are effective and safe for a particular job.”
On The Floor
Coil trends were also seen in mid-May at the annual National Restaurant Association (NRA) Restaurant, Hotel-Motel Show in Chicago. One trend is to engineer the coils so they can be easily isolated and replaced to reduce costs and downtime for the unit. “Such a unit can be positioned as a ceiling-mounted, mullion, up-blast, or frost-discharge coil,” said Danny Sanchez, production manager for Turbo Coil Refrigeration Systems, the exhibitor of the technology. “This versatility allows the coil to fit the design, rather than catering to the limitations of the coil.”
The stainless steel, compact evaporator coil was one of 24 innovations among 2,000 exhibitors to win Kitchen Innovations Awards, selected by an independent panel of food facilities consultants and executives.
Evaporator coil options, including back-mount coils for behind the counter bars, top-mount thin-profile coils for the top of refrigerators, and mullion coils for under counter reach-in refrigerators — all shown by Amco Mechanical, also garnered attention at the trade show.
Publication date: 6/9/2014