Comparative evaluation of three alternative power cycles for waste heat recovery from the exhaust of adiabatic diesel engines
Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced ''adiabatic'' diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum improvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- DOE Contract Number:
- AI01-80CS50194
- OSTI ID:
- 5057540
- Report Number(s):
- DOE/NASA/50194-43; NASA-TM-86953; ON: DE85017352
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
320304 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Waste Heat Recovery & Utilization
33 ADVANCED PROPULSION SYSTEMS
330102* -- Internal Combustion Engines-- Diesel
BRAYTON CYCLE
COMPARATIVE EVALUATIONS
COST
DIESEL ENGINES
ECONOMICS
ENERGY RECOVERY
ENGINES
EXHAUST GASES
FLUIDS
GASEOUS WASTES
GASES
HEAT ENGINES
HEAT RECOVERY
INTERNAL COMBUSTION ENGINES
PERFORMANCE
RANKINE CYCLE
RECOVERY
THERMODYNAMIC CYCLES
WASTE HEAT UTILIZATION
WASTE PRODUCT UTILIZATION
WASTES