Cool Talk

When you’re spec’ing a reefer unit, it’s tempting to jump straight away to the good stuff: how much oomph you need for the job. Every truck or trailer refrigeration system has a maximum capacity, namely its ability to cool or heat space under various circumstances. How much capacity you need depends on the type and size of body or trailer you’re buying, and, of course, what you plan to haul. If you’re taking cut flowers from the field to the market, you won’t need the same amount of gusto as you would if you were delivering ice cream.

The thing is, if you’re a contract carrier, you probably want to be able to pick up a load of tulips one day and go down the street and get skids of strawberry ripple the next. To be a carrier for all seasons–asparagus season, chocolate syrup season, frozen hamburger season, whatever. That kind of flexibility means taking all the reefer unit capacity you can get.

“Capacity” relates to the reefer unit’s ability to affect temperature change, as measured in Btu’s (British thermal units). When you’re comparing rated Btu capacity, you’ll see three interior temps quoted (all at Fahrenheit): 35 F (“fresh”), 0 F (“frozen”), and minus-20 F (“deep frozen”). A reefer’s capacity will be different for each of the three rating points, ranging from perhaps 14,000 to 60,000 or more.

But you can’t look at capacity in isolation when so many other factors affect how efficient your temperature control system can be. Consider the size of the cargo box and the amount of insulation it has. It takes more capacity to cool an over-the-road, 53-foot trailer with thin walls (and an inch and a half of insulation) than a 45- or 48-foot trailer with thicker walls. And no matter how much power your reefer has, if the air doesn’t flow well around (and under) the load, it’ll have to work that much harder to be effective.

As important as capacity, however, is a reefer unit’s ability to maintain a specific temperature range. More shippers and receivers of food are adhering to HACCP, or Hazardous Analysis and Critical Control Point standards. HACCP is a set of international guidelines designed to help make sure food shipments stay within a temperature range that prevents harmful bacteria from growing. In the United States, the U.S. Food and Drug Administration has endorsed HACCP in the way it regulates seafood and juices. The U.S. Dept. of Agriculture uses it for meat and poultry processing plants, as well. And the FDA is considering regulations that would establish HACCP as the food safety standard throughout other areas of the food industry, including both domestic and imported food products.

With hospitals, hotels, and grocery stores structuring their food-supply bids to include verification of food-safety programs, shippers have to keep detailed records showing that HACCP controls are working. They feel most vulnerable to a breach of compliance when the food is in transit or sitting on a hand truck, so they’ll install a Ryan Recorder or some other type of temperature logger with each load.

Being able to track temperatures from the cold storage warehouse to the delivery dock, while providing specific records for shippers with HACCP plans in place, constitutes a big-time competitive advantage for a freight carrier. Speedy microprocessor controls in reefer units let you check detailed information about each trip, from your arrival and departure times to the temperature within the trailer–heck, within each compartment–at each leg of the journey.

However, data loggers and computer controls won’t do much for you when there’s a problem on the road.

Trucking companies can use their two-way communications systems to relay interior temperatures, trigger open-door alerts, and control reefer functions, but typically the trailer has to be hooked up to the tractor. ReeferTrak gives you the same kind of two-way controls without any wires at all. Developed by Startrak (www.startrak.com) and supported in Canada by Cancom Tracking (www.
cancomtracking.com), ReeferTrak lets you set your trailer thermostat, conduct pre-trip operations, or perform any command or poll reliably in real-time–the unit’s low power draw means it’s always on. If there’s a problem, you can have the system notify you via e-mail, the web, fax, and/or pager.

Thermo King (www.thermoking.com) also offers an untethered monitoring system, except this one is wired directly into the reefer unit. Trac-King uses a Global Positioning System (GPS) to determine the trailer’s location and satellite or digital cellular communications to report information about the load and the performance of the reefer unit from just about anywhere in North America. All of the information is available at a password-protected web site.

Trac-King is part of a suite of remote monitoring products from Thermo King. The company’s R-Com unit, introduced last year, is a radio-based wireless system that can document when a trailer arrives and leaves a particular location, what its operating temperature and condition is, and if any alarms have been sounded. The R-Com system can be used for one-way or two-way communications, so you can adjust trailer temperature settings without having to leave the office, and Thermo King’s FleetWatch software organizes the information into concise, customized reports.

Multiplexed trailer wiring, used to light an in-cab fault light for your antilock braking system, has opened new electronic channels between the tractor and trailer. Using the J560 cable, it can bring the reefer unit’s warning lights into the cab as well as display trailer interior temperatures or warn the driver when the trailer door has been popped open.

Wheel Monitor (www.wheelmonitor.
com), a Niagara-on-the-Lake, Ont., company known for its wheel and brake monitoring system, is one of several manufacturers producing an onboard computer and in-cab display that take advantage of multiplexing. “The nice thing about the system is that not only does it monitor the overall temperature within the trailer but also the upper, lower, front, and back temperature–anywhere you can place a sensor,” explains Wheel Monitor president John Mantini.

That means the driver no longer has to rely on a glance into his side-views to check the reefer’s status, he just has to watch the screen in front of him. And with the right communications package, he can bet that his dispatcher, operations manager, and even the shipper are getting regular e-mail messages from the unit itself saying everything is cool as can be.

Now how’s that for oomph?Looking for an opening to talk to a customer about waiting times and responsibilities for loading, sorting, and palletizing freight? Two words: food safety.

Good food-safety practices encompass how the freight is packed and placed in the trailer, and how much of a temperature swing it can stand. Work with your customers and consignees to ensure the safety of the food you haul, nailing down procedural details like what to do when the temperature differs from the requirements on the bill of lading (at the loading dock, in transit, etc.).

In the process, you’ll more clearly define what you’re responsible for and reduce the chance that you’ll be hung up at the border during an inspection or on the hook for a load of melted ice cream. Here are two places to start and some questions to address:

1 The dock. What steps should be taken to ensure safe food temperature? Is the food product loaded under conditions that prevent temperature abuse? Is the load configured so the temperature can be distributed evenly? Does load stacking consider cross-contamination–e.g., do you put the windshield-washer fluid on the same skid as the crates of oranges?

2The vehicle. Does the truck reefer unit system provide single or dual-temp performance, and are there separate compartments for refrigerated and frozen freight? Can the proper temperature be maintained during short and long hauls? Is in-cab load temperature verification available? Is full-time temperature recording available for downloading at the load destination? How is a road emergency handled?