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NREL's Complete-Cab Truck Climate Control Package Showcased in Automotive Engineering

June 6, 2016

Long-haul Class 8 trucks use approximately 7% of their fuel for rest period idling, consuming more than 667 million gallons of fuel each year nationwide. NREL has identified a package of climate control technologies that annually can save 774 gallons of fuel used per truck for rest period air conditioning, with the potential for full payback on equipment investments in about three years. In a recent Automotive Engineering article, reporter Paul Weissler asked NREL's Jason Lustbader for an overview of these complete-cab solutions.

"The project goal was to reduce cab thermal loads to enable smaller, lighter, and more cost-effective idle-off climate control equipment," explained Lustbader, who heads up the lab's heavy-duty vehicle thermal management research.

Manufacturers know that comfortable sleeper compartments are high priorities for drivers. In response, some trucks are designed with more than 370 cubic feet of living space in the sleeper.

NREL researchers have developed and evaluated an integrated suite of technologies to reduce the energy loads and fuel use associated with the heating, ventilating, and air conditioning needed to maintain driver comfort when long-haul trucks are parked and idling. The Complete-Cab Thermal Load Reduction Package included Thinsulate insulation, ultra-white paint, and advanced window shades designed to complement a battery-powered auxiliary HVAC unit.

These combined thermal solutions reduced the air conditioning load by 35.7% and the heating load by 43%, with an even more impressive 53% reduction in heat-transfer coefficient when another layer of advanced insulation was added. Modeling with NREL's CoolCalc load-estimating software showed major reductions in battery capacity requirements and improvement in air conditioning performance.

"Combining thermal load reduction technologies with battery electric air conditioning can improve system payback period and performance, providing fleet owners with additional economic motivation to adopt the technology," Lustbader said.

NREL researchers work with industry partners including Volvo Group NA, PPG, and Aearo Technologies on these projects to optimize the thermal performance of light-duty and heavy-duty vehicles, as well as providing the technical and deployment expertise needed to help make vehicle fleets more fuel efficient and environmentally friendly.

To learn more, read NREL's recent report on long-haul truck sleeper heating load reduction.