Heavy-Duty Vehicle Thermal Management
National Renewable Energy Laboratory (NREL) researchers are assisting heavy-duty vehicle (HDV) manufacturers and operators with energy efficiency technology to mitigate high fuel costs and meet more stringent idling regulations. NREL's HDV thermal management program, CoolCab, focuses on optimizing truck heating and cooling systems to improve efficiency while reducing operating expenses, fuel consumption, and tailpipe emissions.
Cab climate control during driver rest periods requires running the engine and burning additional fuel. In the United States, long-haul trucks use approximately 667 million gallons of fuel each year for rest period idling, 6.8% of their total fuel use. Truck workday idling consumes more than 2 billion gallons of fuel each year.
The CoolCab project researches technology and methods for improving truck cab heat transfer and climate control system performance, and works with vehicle and component manufacturers to develop effective solutions. NREL researchers use both testing and modeling of heavy-duty vehicles to assess the energy saving potential of advanced materials and equipment, including films, paints, advanced insulation, micro-environmental design, and idle reduction technologies.
Enhancing the thermal performance of truck cabs will enable smaller, lighter, and more cost-effective idle reduction solutions. In addition, if fuel savings from new technologies can provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them.
While HDVs and advanced thermal management technologies undergo assessment at NREL's Vehicle Testing and Integration Facility test pad, researchers also use a wide range of computer-based modeling tools to evaluate performance. CoolCalc and CoolSim vehicle thermal management modeling tools are available to researchers and outside partners for use in simulating climate control energy use and calculating the potential benefits of thermal load reduction options.