You’re very familiar with them. Likely you may drive them. Reefers, or refrigerated trailers, are an essential part of the freight supply chain. These vehicles haul freight that needs to be kept at very specific temperatures for very specific reasons.
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Even so, trailer refrigeration technology has remained relatively static over the years. So, what will the refrigerated trailer of tomorrow look like? Can we expect strong, lightweight material made of corrosion-proof materials? For many manufacturers, that is certainly the hope.
Evolution of the Reefer
For many years now, engineers have been involved in design improvements to temperature cooled trailers. Economic, efficient aluminum-sheet designs becoming the norm.
Still, far too many reefer trailers are made of sheet-and-post walls. The floors are generally supported by underbody crossmembers.
One thing truck drivers and fleet technicians are continuing to see is the use of non-metallic materials. Things like aluminum are great for strength, but it also conducts heat very well. Inside a wall cavity, they contribute far less to the trailer’s overall heat signature. This is where design comes in.
New trailer walls will come with a void between the inner and outer metal panels. The void between the aluminum is then filled with polyurethane foam insulation. The foam then acts as both an insulator and limits heat conduction, or any internal cold seeping through trailer walls.
Another way to better insulate a reefer trailer is to surround the narrow interior posts with foam. The one-inch posts, located within a 2-inch wall, allows for injection room between the open spaces.
More changes to foam insulation comes in 2020, when the federal government is making the switch to a more environmentally friendly foam. The “blowing agent” used in current industrial capacity foam for commercial vehicles is not environmentally friendly, which is what is prompting the change.
Greater Efficiency
Also, being looked at for increased reefer efficiency are aerospace-like composites. These advanced materials use little to no bolts, rivets or crossmembers, thus greatly decreasing the areas where air can escape.
Panel-type composite reefer trailers uses a molded structure that gives the 53-foot trailer up to 25% improvement over thermal performance, while at the same time being 20 percent lighter than conventional trailers.
These composites are a mixture of fiberglass, carbon fiber and resin. Carbon fiber is used for strength, and the rest of the materials help resist corrosion and other chemicals.
While many of these prototypes are currently being tested, how will they fare on actual roads, and will there be any repair issues when a technician is working on a trailer he or she is simply not familiar with?
Certainly, the area of maintenance may be the biggest stumbling block to full-scale adoption. Much like working on a truck hood, which is made of fiberglass, repairing these new advanced materials generally takes a sidewall patching material. Will there be a premium for these new materials?
Electric Reefer Units
The new buzzword on the block is in electric reefer units. Solar-generated electricity will supply all the power the trailer needs. This will save on both time and money and make the trailers far more reliable.
These electric systems also serve as a great way to cut back on exhaust fumes and greenhouse gases. And since there is charging infrastructure in place all around the country, these systems can be used for single or multi-temperature moving and stationary cold storage, as needed.
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Shore power can be used at the docks but is expensive in yards. Since long stretches of wiring must be buried, human error – such as driving away still plugged in – increases the risk of unforced error.
Still, as technology marches forward unapologetically, expect to see the reefers of the future become the reefers of today.