Modern refrigerated trailers tread lightly and protect perishables.
“When it comes to reefer trailers, reduced weight is even more important than in van trailers,” says Rod Ehrlich, chief technology officer at Wabash National. “Foodstuffs tend to be heavy, and people want to haul product, not trailer.”
Joe Stianche, fleet manager for Laurel, Miss.-based Sanderson Farms, agrees. “The trick is to make a refrigerated trailer as light as possible – without compromising thermal efficiency or durability,” Stianche says.
Loads in, corrosion out
In addition to standing up to the rigors endured by any other type of trailer, reefer trailers face unique conditions. For example, they must insulate their loads, and resist corrosion from load moisture. That’s tricky, since moisture can collect behind seams, scuff liners and even fasteners.
“We used to use aluminum scuff liners,” says Ehrlich. “They would dent easily and pull away from the inside walls, and they were difficult to repair. Now we use a high-performance plastic that’s fused in place. And if they get damaged, they’re easily repaired.”
Ehrlich also cautions against using pressure washers on seams and fasteners, since that drives moisture into the insulation, where it compromises insulating ability and corrodes metal.
And corrosion isn’t limited to bodies; reefer frames are just as vulnerable as those on any other trailer. “I’ve had trailer webs with holes so big you could put your hand through them,” says Darry Stuart, president of DWS Fleet Management Services, based in Wrentham, Mass. “That’s why I started spec’ing stainless steel and aluminum subframes, but that added $4,000 to the cost of each trailer, and the fleet almost had my head.”
No doubt, trailer manufacturers are taking more precautions against corrosion, but the war is far from over. “Corrosion is still getting worse,” Stuart says. “We’re seeing better coatings, and just driving on the highway, you can see a lot more stainless and galvanized steel. But the use of these new de-icing chemicals is spreading faster than the industry can keep up.”
But that may be changing. CorroGuard, a spray-in-place thermoplastic elastomer coating, is the newest addition to Great Dane’s protection package to fight corrosion. Applied to suspensions and support gear, CorroGuard is said to protect against road abrasion and corrosion, and resist de-icing chemicals, snow and road debris.
Reefer interior materials have improved, says Charles Cole, manager of technical sales and product training for Utility Trailer. “Lining materials are better, such as woven glass fabric like Armortuf by Kemlite,” Cole says.
Chris Hammond, vice president of dealer sales at Great Dane, agrees. “Interior linings have added puncture resistance and reduced weight, while adding useful life and reducing maintenance,” Hammond says.
Another consideration is how much solar heat the roof absorbs. The lighter in color the roof is, the better it reflects light and heat, which reduces the load on the reefer unit. “But aluminum roofs darken over time,” says Ehrlich. “That’s why we offer our Solar Guard roof, which won’t darken. And because it forms a superior bond, we’re able to use half as many roof bows as conventional designs.”
Interior lighting poses yet another challenge unique to refrigerated trailers. That’s because with conventional fluorescent lights, the colder the interior temperature, the dimmer the lights. “Interior LED lighting has become popular despite the cost,” Hammond says.
“LEDs are better suited for multi-temp operations because they burn brighter, especially in the front compartment, which is the coldest. In addition, they require less maintenance because they are not as susceptible to shock, and they activate instantly instead of warming up to full brightness.”
If reefer trailers have an Achilles’ heel, it has to be the floor, says Sanderson Farms’ Stianche. “They can only take a finite number of forklift landings before they break,” he says. “And when that happens, the trailer’s useful life is over. They’re better than they used to be, but they’re not quite there yet.”
The evolution continues
There seems to be little doubt that reefer units and trailers have evolved for the better. “There are better interior materials that reduce wall damage,” Stianche says. “And the units are more durable. Refrigerant is no longer a consumable item, electrical systems and controls are more sophisticated and more robust, and self-test capability really has helped. I can’t think of an area that hasn’t gotten better.”
Signed, sealed, delivered
In transporting refrigerated goods, information pertaining to the condition of a load during transit is just as important as the load itself. The latest refrigerated units from Thermo King and Carrier Transicold are teeming with such information, providing critical data such as temperatures, fuel levels, engine fault codes and battery levels.
Most refrigeration units have the ability to produce trip performance reports for the receiver. Some fleets, however, do not want drivers to touch the equipment while in use. Through a remote monitoring capability known as telematics, fleets can confirm that the refrigeration unit is set to the operating parameters consistent with what was requested by their customer, says David Wilson, telematics product manager for Thermo King.
In addition to customer service benefits, telematics also supports fleets’ maintenance programs. Fleets can establish baselines for fuel usage and performance data, including factors like engine run hours. Anything that deviates from the norm can be monitored conveniently in real time through alerts, says Mark Fragnito, product manager
of electronics for Carrier Transicold.
Both Thermo King and Carrier have developed a standard interface protocol to allow third-party providers of telematics solutions to monitor and transmit information from the reefer unit. GE’s VeriWise cellular-based solution is compatible with most Thermo King and Carrier Transicold models, says Robert Montgomery, GE product manager for VeriWise. Standard location and event data is accompanied by reefer power status, operating mode, return air temperature, setpoint, operating hours, battery voltage and fuel level. The product also combines the information to show active alarms and fault codes with each event, Montgomery says.
The user can establish a “profile” for a type of load, including allowable temperature ranges, reporting profiles, exception handling, etc. The system also accumulates a rolling “reefer log,” recording temperature and setpoint for up to three zones according to the profile settings. The logs can be kept on the VeriWise unit for weeks to months, depending on the interval. When needed, the reefer logs can be downloaded to the website, and then to Microsoft Excel or Adobe PDF for use as proof of quality for the end customer, Montgomery says.
Both Thermo King and Carrier also have designed their refrigeration units to allow for two-way communication. This feature allows a fleet manager to remotely control tasks such as starting the unit, selecting temperature set points or running diagnostic routines.
Thermo King units use the company’s own satellite-based tracking system called Trac-King for two-way communication. Carrier offers a free software upgrade for the unit controller called DataTrak; this upgrade allows microprocessor information to be extracted via the providers’ telematics systems, Fragnito says. In June, the company will begin to allow various third-party telematics systems to use DataTrak for two-way communications.
CarrierWeb will be one of the first third-party telematics solutions to offer two-way communications through Carrier Transicold, says Norman Thomas, vice president of marketing for CarrierWeb. The company recently released ReeferMate, an untethered trailer-tracking system for refrigerated units. The system costs about $850 and $20 per month for wireless costs – assuming fleets decide to receive automatic trailer position and reefer status updates every hour. The system also transmits exception alerts in real time.
CarrierWeb also offers a tethered trailer-tracking version that uses an RFID-based tag on the trailer to communicate trailer ID and temperature to CarrierWeb’s computing and mobile communications platform in the tractor.
For refrigerated carriers, telematics offers real solutions for adding a virtual layer of protection to cargo in transit.