[what's new in:]APUs

July 1, 2011
With an ever-increasing number of regulations limiting idling, and fleets wanting to cut fuel costs, there has never been more focus on auxiliary power units than there is today. The units can save fleets money and create comfortable cab environments to help with driver retention. And with today's newer systems, longer run-times and more consistent cab temperature are just two of the benefits. Espar

With an ever-increasing number of regulations limiting idling, and fleets wanting to cut fuel costs, there has never been more focus on auxiliary power units than there is today. The units can save fleets money and create comfortable cab environments to help with driver retention. And with today's newer systems, longer run-times and more consistent cab temperature are just two of the benefits.

Espar Products was the first company to have its anti-idling truck heating products certified by the California Air Resources Board, according to John Dennehy, vice president of marketing & communications. The Airtronic line, which includes the D2 bunk heater and the Airtronic D4 and D5, use forced hot air and produce between 7,500 and 41,000 Btu/hr. All are CARB-certified, as is the company's Hydronic 5 engine preheater. The Hydronic line, including the Hydronic 5, offers between 3,700 and 120,000 Btu/hr. It eliminates engine idling for cab warm-up, maintains temperatures, and provides rapid window defrosting capabilities by circulating the engine coolant for faster heat transfer.

“Our customers want compact, easy to maintain and service heating systems that do more than just heat. They want systems that can heat fuel [and also] hydraulics; integrated heating systems with electrically powered air-conditioning systems; and also APUs and gensets,” Dennehy adds.

The company's products are available as OE-installed options, and these include Espar heaters that use 12- or 24-volt battery systems, and gasoline or diesel as an onboard fuel with sealed combustion chambers to create heat.

Customers are asking for “a complete solution to the idling dilemma,” says Bill Gordon, vice president-aftermarket & Nite sales for Bergstrom. “Bergstrom was the first to offer a battery-operated system. The battery-based Nite system is CARB-approved, and available [through] both the aftermarket and factory-installed through Navistar, Freightliner and Peterbilt.”

According to Gordon, the use of more efficient components has increased both Btu capacity and run-time for Bergstrom's units. “Buyers must beware of how Btus are calculated, as many in this industry do not use TMC or any standard Btu calculation,” Gordon cautions. “Often the Btus are highly inflated.”

Bergstrom's products include both sleeper and day cab AC units, batteries, fuel-fired heaters, inverters, chargers, and shorepower kits. “We try to identify technologies that will be in use in five or ten years, not just react to what others are doing today,” Gordon adds.

“Fleets generally choose APUs for fuel savings and idle reduction,” says Dean J. Lande, manager-business development for Carrier Transicold. “Some APUs provide additional solutions. For example, Carrier Transicold's APU provides both heating and cooling, and covers hotel loads in the sleeper.”

Truck engine warming, battery charging capabilities, and shorepower connectivity are included, he says.


For fleets in warmer climates, the APU must provide at least eight hours of continuous cooling. To improve comfort, Carrier Transicold's diesel-powered APU was recently upgraded to provide 12,000 Btus of cooling, 20% greater capacity than previous models.

Fleets also want technical support no matter where the unit goes, Lande says. “Choose manufacturers that provide nationwide service support. If an APU needs service while on the road, you don't want your driver in a situation where there are no service centers for miles,” he explains.

Centramatic offers an APU/HVAC split system that is a stand-alone unit with its own cooling system. It can serve as a backup of the truck's alternator and factory-installed HVAC system should a failure occur, says Mike Hagar, director of sales & marketing.

“Centramatic spent two years doing research and testing to develop the highest-quality unit available and [with] ease of service,” Hagar says.

The unit includes auto start, 60 amp 12-volt power supply and low oil pressure, or high-water temperature shutdowns. The HVAC includes a fully programmable climate control and digital thermostat.


At Glacier Bay Technology, the extension of battery life through the tight controlling of the charging pattern is helping its ClimaCab electric APU provide 10 hours of temperature control while cutting fuel costs.

“Our customers are asking for the maximum amount of idle percentage reduction and diesel fuel cost savings they can get by using our all-electric APU,” says CEO Derek Kaufman. “They also want to avoid additional maintenance costs if possible. By maximizing the efficiency of the energy draw, we can provide more than 10 hours of sleeper bunk climate control using a four-battery system.” According to the company, ClimaCab users can save as much as $4,800 per truck per year and eliminate over 17 tons of carbon dioxide over an average truck idling 2,000 hours per year.

“Our customers [want] a reliable APU to help them increase uptime, reduce maintenance costs, and increase driver retention,” says Paul Barbaro, product manager-APU, for Thermo King. “[And] they want an APU that is very fuel-efficient to help meet their need to increase energy, operational efficiency and sustainability.”

Through its extensive service and dealer networks, Thermo King is helping meet those requirements with its TriPac and TriPac E APUs. The company says its TriPac E uses an NXT dry cell battery, which offers 30% more run-time than a standard wet cell battery, with an operating range of -40 to 180 deg. F. The unit can save a fleet over $7,000 a year in fuel over a vehicle idling 2,500 hours with a fuel price of $3/gal., Thermo King says.

Power inverters and inverter/charger combination units can be used as stand-alone products or in conjunction with an APU to power such things as entertainment systems, microwaves, or coffee makers. Xantrex Technology USA, which produces the Prowatt SW series of compact and lightweight inverters, is focused on developing low-cost, high-efficiency units.

“Fleet managers are under extreme pressure to maintain profitability in the wake of escalating fuel prices and a tough economy,” says David Norman, director of marketing & strategy. “We have learned from our partner fleets and APU manufacturers about the need for low-cost, high-efficiency power inverters that meet UL458, a safety and quality standard recommended by … TMC and SAE.”

The Prowatt SW uses pure sine wave output, and the Pro series offers a modified sine wave output and a built-in transfer switch.

“Drivers diagnosed with sleep apnea must use the correct inverter, preferably a pure sine wave unit and installed at the OEM level, to operate a CPAP, the machine used to treat their disorder,” Norman notes.

Carrier's APU provides heating, cooling, and hotel loads.


Bergstrom Inc.

Carrier Transcold


Espar Products, Inc.

Glacier Bay Technology

Thermo King

Xantrex Technology

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