Hupfer, R. and Habbel, G., "Development of a Method for the Long-Term Efficiency and Cost Evaluation of Mobile Idle-Reduction Technologies (MIRT)," SAE Technical Paper 2010-01-2031, 2010, doi:10.4271/2010-01-2031.
The heavy-duty truck industry has adopted various methods and technologies to provide comfort in sleeper cabins during rest periods.For heating a sleeper cabin the fuel-operated heating technology has been used already industry wide, due to performance, ecological, and economical reasons. The same criteria apply to the comfort requirements in the summer or in warmer climate.One of the most common methods is still the idling of the main truck engine. While engine idling increases both fuel consumption and emissions, it is also having a negative effect on the engine and exhaust system maintenance, especially with the latest changes of the emission regulation and the application of active and passive Diesel Particulate Filter (DPF) regeneration strategies.Alternative methods and technologies for cooling Mobile Idle Reduction Technologies (MIRT) are auxiliary power units (APUs), which include a combustion engine driven generator, but also battery based electric cooling systems and thermal storage technologies, based on phase change materials (PCM).While in the past the requirements for comfort equipment in trucks were mainly driven by performance criteria, a new approach will present the balance between performance, long-term durability, and life cycle costs.The paper will present a method to evaluate the cost of the energy provided in the sleeper cabin, considering different MIRTs under the industry criteria, with a special focus on the long-term durability and life cycle costs, which are becoming more important due to the longer life cycles of fleet vehicles.This approach provides a complete method to compare the different MIRT systems not only regarding the output of performance and emissions, but also regarding the necessary input of fuel and equipment related cost.The main focus on this evaluation is between the electrochemical energy storage systems of batteries, and the thermal storage system, which accumulates the energy in a PCM for the cooling of the truck cabin during the rest period.Both systems provide the advantage of reduced idling and therefore have a positive effect on fuel consumption reduction and minimizing of emissions.While the electrochemical battery provides the energy with limited lifetime expectations, the thermal storage core with highly increased life time will provide the most efficient return on invest for longer life cycles of fleet applications. The paper will provide the relevant data.