Low-Cost Scroll Organic Rankine Cycle

Heavy-duty diesel vehicles lose on average a third of their engine efficiency to thermal waste heat and a further tenth to parasitic electrical draw for auxiliary electrical systems from mechanical efficiency. These inefficiencies contribute among others to their average fuel economy of six miles per gallon, well below EPA 2027 targets for reduced emissions and improved energy consumption. Despite decades of investment in diverse efficiency improvements, several mature technologies remain unrealized due to uneconomic payback periods longer than the expected life of the vehicle and poor cost per kilowatt ratios. Air Squared proposes the Low-Cost scroll Organic Rankine Cycle (LOC-ORC) with a $500 per kilowatt cost target producing 30 kW of usable electricity to improve fuel economy by 10% on state-of-the-art class 8 vehicles. The LOC-ORC uses next-generation spinning scroll technology and advanced reduced footprint micro-tube heat exchangers to reduce weight and increase power for optimized transportation waste heat recovery. Capturing low-grade waste heat from diesel engine thermal losses, the proposed technology can increase modern tractor-trailer fuel economy while producing net-zero emissions. By eliminating inlet and outlet valves and reducing part count, spinning scroll expanders can drastically reduce costs compared state-of-the-art waste heat recovery engines. Air Squared has extensive experience leveraging scalable assembly, low-cost sourcing, and advanced machining to drastically reduce component costs resulting in strong commercialization of otherwise prohibitively expense solutions. The same cost-cutting measures could be applied to the LOC-ORC, eliminating superfluous components and identifying low-cost alternative materials to bring the LOC-ORC cost to $15,000, producing the most cost-competitive diesel engine ORC on the market.With all-electric heavy-duty vehicle market dominance still a generation away on the horizon, the hybridization of diesel engine freight transportation with waste heat recovery electrification is an achievable milestone on the way to increased utility vehicle fuel economy. The 300,000 modern tractor-trailers produced annually transporting 11 billion tons of freight in the US alone could save over $6,000 a year in fuel cost by implementing the LOC-ORC. It is projected that the proposed LOC-ORC would be widely adopted by modern semi-truck manufacturers as a cost-effective way to increase fuel economy and reduce fossil-fuel emissions with a realistic payback period of under three years.