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tag A NEW TEST STAND FOR INVESTIGATIONS OF ORC-EXPANDERS - EVAPORATION BEHAVIOR OF ETHANOL AND ETHANOL-WATER MIXTURES
Martin K. Günzel, Roland R. Scharf
Session: Poster session & Welcome drinks
Session starts: Wednesday 13 September, 17:30



Martin K. Günzel (Leibniz University Hannover - Institute of Power Plant Engineering and Heat Transfer)
Roland R. Scharf (Leibniz University Hannover - Institute of Power Plant Engineering and Heat Transfer)


Abstract:
Organic-Rankine-Cycle- (ORC-) technology is considered as an additional system to improve the energy efficiency of combustion engines. The concept is to use the hot exhaust gases to evaporate the ORC-fluid. Other than, for stationary utilization the ORC-technology has not been scaled down to mobile uses, such as in trucks, coaches, trains and or other mobile work machines, yet. In these applications, new challenges arise, due to variations in the load profile of the engine. For safe operation, turbinetype expanders require well defined working fluid parameters for the superheated steam. Decreasing engine load and related lower exhaust gas flow requires adjusted mass flow-rates in the ORC. In this study the evaporation behavior of ethanol and ethanol-water mixtures was investigated in a standard finned tube evaporator. The mass flow was gradually reduced from the design point at various constant steam parameters. The inlet temperature of the exhaust gas was maintained constant. The exhaust gas flow was varied until the evaporation including overheating of the ethanol or ethanol-water mixture were stable. The influence of the heat transferability as a function of exhaust mass flow and steam mass flow as well will be discussed. In addition, a comparison is made between undenatured ethanol and ethanol denatured with methylethylketone (MEK). Furthermore the thermal decomposition of the investigated working fluids has been monitored during the tests.