Bottom Line
Powering up for comfort

by Ruth Jones

As long as trucks have been on the road, truckers have been idling their engines. They say they do it to stay warm (or cool) while they sleep, or to keep their engines from freezing up in very cold weather. While idling may work as far as the driver's comfort is concerned, any idling engine has a shortened life expectancy and wastes a lot of fuel.

How much fuel is wasted? The Argonne National Laboratory at the University of Chicago researched this question on behalf of the Department of Energy. Argonne transportation analysts estimate that a typical Class 8 long-haul truck consumes about 1,890 gallons of diesel fuel per year through overnight idling alone. So, if you're an owner-operator who routinely idles your engine while you sleep, imagine yourself setting fire to 20 or so crisp $100 bills. That's a lot of money to go up in smoke, not to mention the money you're likely to need for an engine overhaul before your truck is even paid for.

The pollution generated by idling big rigs has become the target of federal, state and local governments as well as environmental groups. A number of communities have already banned or restricted idling, and many more are likely to implement bans over the next few years, with fines for violators in the "stiff" category. While cleaner air is certainly a desirable goal, the fact remains that truckers must have the means to rest comfortably - highway safety depends on it.

Nowadays, electronic engines have "kill" switches to limit idling. Many hired drivers report that the fleets that employ them strongly discourage idling, with penalties ranging from reprimands to loss of bonuses. But few fleets offer their drivers any alternative to idling in order to sleep comfortably.

New technologies make it possible for some engines to turn themselves off and on while the rig is parked in order to keep a sleeping driver comfortable, to maintain engine temperature, and keep batteries charged. However, some truckers have expressed doubts about the quality of sleep they can get with the engine starting and stopping itself throughout their hours of rest.

An auxiliary power source that would eliminate the need to idle the engine would seem to be the obvious answer to the problem. Yet, for reasons that confound the experts, auxiliary power sources have not gained widespread acceptance in the industry, with estimated use at five percent. Among owner-operators, auxiliary power sources are generally perceived as luxury items, usually associated with customized sleeper set-ups. As environmental regulations continue to tighten, this perception will likely change as both owner-operators and fleet owners are forced to find a workable alternative to engine idling.


The latest offering from Webasto Thermosystems, a Lapeer, MI, company with over97 years of experience in the transportation industry, is the ThermoCooler. The ThermoCooler is a packaged system consisting of a cool storage reservoir and a fuel fired heater that provides heat for the engine and the sleeper, as well as a unique means of allowing a driver to sleep in air-conditioned comfort without idling the engine.

To provide air conditioning when the truck is parked, the ThermoCooler stores the cold produced by the vehicle's primary air conditioning system while the vehicle is in motion. Chilled coolant circulates in a closed loop through the sleeper's rear evaporator/heat exchanger and around an array of tubes inside a storage unit. The tubes are filled with an environmentally safe solution that freezes at 49 degrees Fahrenheit. When the driver activates the system, chilled coolant is circulated back to the heat exchanger, and chilled air is delivered to the sleeper through existing ducts. Charging time for the unit is four to six hours, resulting in up to eight hours of air conditioning for the sleeper.

Heat is provided by circulating engine coolant through the fuel-fired heating unit. The system features an interleaved heat exchanger in place of a re-circulating air system to improve efficiency. The heated coolant flows from the heater outlet to the rear heat exchanger, heating the air and delivering it through existing ducts in the sleeper. In addition, coolant is circulated to the engine, keeping it warm enough to start in severe weather.

Power Pak

A product of International Power Sources (IPS) of Burnsville, MN, The Power Pak is an auxiliary power system that operates on diesel fuel drawn from the truck's main tanks. The unit provides AC power to operate 110-volt appliances, air conditioning for the sleeper and cab, a micro-furnace for heating, and block heating for the engine, as well as DC power to recharge the main batteries. It has a 45-amp DC charging system, an AC distribution panel with circuit breakers, sleeper mounted controls, and provides 8000 BTUs for cooling and 5500 BTUs for heating. A water-cooled 2-cylinder LOMBARDINI LDW502 diesel engine and a B105 Brushless Mobile 6KW generator power the unit. Fuel consumption ranges from one pint to one quart per hour, depending on usage. The Power Pak weighs 350 pounds and is 26 inches long, 23 inches high, and 22 inches deep. IPS offers truckers a lease program.


Eberspaecher, a European company manufacturing fuel-fired heaters, entered the American market in the '70s under the brand name Espar. Espar offers truckers a line of compact, diesel-fired cab heaters to keep sleepers and engines warm without idling.

Pony Pack

Rex Greer, a long-haul trucker, took delivery on a new Peterbilt with a 285-inch wheelbase and a 100-inch custom sleeper in 1984. Greer was running from California to Florida back then, and was looking for a way to stay cool while he slept without idling his truck. He had an idea that a small, diesel-powered engine with a 12-volt alternator could take over the chore of heating and cooling from his truck's engine. No one else concurred with Rex's theory, so he decided to design and build it himself. The result was the Pony Pack.

Today's Pony Pack utilizes a 10.8 horsepower diesel engine that consumes about one and one-half pints of fuel per hour. The unit weighs about 300 pounds and takes 24 inches of frame rail space. Its 105-amp alternator provides 12-volt power to operate the truck's existing heating and air conditioning systems and provides power for in-cab appliances. LL