Cool Orange

Finding the right solutions for engine-off cab cooling.

Beauchamp agrees that this is the "hot topic" of the day for the company. He is supervising the installation of the different test technologies the company has chosen as its "finalists."

The nominees are:

Webasto BlueCool—a storage solution that uses cold air from the engine air conditioner while the truck is in motion to "pre-cool" a chemical solution. Once the solution is cooled and the driver goes to sleep at night, it is passed through a heat exchanger, very much like an evaporator coil. The exchanger dehumidifies the warm cab air and blows cool air into the bunk area.

Bergstrom NITE System—a battery solution that combines an Espar direct-fired cab heater with a 12 V air conditioning system that is installed under the sleeper bunk. The cooling component runs off a battery pack that can run up to 10 hours between recharges.

DC Airco—a cooling-only battery solution that uses a 12 V air conditioning unit mounted on the outside back wall of the sleeper. This system can run off the truck's starting batteries, or an independent battery pack.

Caterpillar MorElectric—combines an auxiliary power unit (APU), or genset, with shorepower capabilities. Still in testing—Caterpillar has not announced a production date.


"The strength of the APU is that it has a lot of capacity and can provide as much cooling as is called for in the tractor, day or night," Damman says. But he also points out two key weaknesses: cost and required maintenance.

"Even if you're idling at 40 percent or 50 percent, it's very difficult to come up with a payback for that technology," he says, "because realistically you need the air conditioning system from the middle of May to the middle of September in about 80 percent of the country. So you have a technology that costs a lot, and provides four months' worth of benefits, but there's a risk for the other eight months, if the driver runs that genset to power cab electrical needs, all your payback is used up the months that you don't need it."

In addition, Damman says, the maintenance needs of the APU can upset regular maintenance schedules. Schneider has found that in some cases the APU's engine needs service twice as often as the truck engine.

The battery and storage systems offer a very different cost/benefit dynamic, according to Damman. Compared to an APU, these systems cost less and are easier to maintain. "In fact, unless there's a breakdown, there is no maintenance," he says. "Some of our evaluation units are three years old, and they're still on their original batteries. That's fairly positive. They're also quiet; you don't have another motor running, so there's no vibration."

There is one negative, however, and that is that battery and storage systems don't have as much capacity as either the tractor air conditioning system, or the APU. "You have to use them more wisely," Damman explains. "But we've found that the drivers have been able to make them work, and are satisfied with the output and the performance, and in fact prefer them over the gensets that we've evaluated, because there's less noise, less vibration, and in total they're easier to use."

To enhance the performance of all the systems, Schneider gives drivers the option of using an insulated bunk curtain that keeps the cool air in the bunk while allowing the driver to watch TV from bed. This simple accessory holds the cooled air in the sleeping area, effectively maximizing the system's cooling capacity.


Of course, it's not enough that a system makes Damman and Beauchamp happy. If the drivers aren't pleased enough to want to use the technology, then all that effort and expense will have been wasted.

"Total value is what will drive the final decision, but there are positives and negatives to each technology," Beauchamp explains. "BTU output will be a big thing to the drivers, and if they can get a full ten hours out of one of the technologies, that will be a plus. Webasto has changed its approach enough that we're not totally familiar with what it's going to do. Previous iterations didn't provide what we wanted, but the new one looks like it might. The battery-powered ones are simple enough that it looks like, with proper management by the driver, they will accomplish that as well, and possibly have a higher BTU output."

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