Abstract
Keywords: Steam cycle, Gas cycle, Thermoelectricity, AMTEC, Energy recovery
CO2 Emissions are in the focus of the current discussion. Improving the energetic efficiency of vehicles therefore is requiring continuing efforts. The introduction of hybrid drive trains can be taken as an indication that the potential in classical power train technology have been explored and exploited to a significant degree.
Before us is the challenge to harness the branched energy flow through vehicles more precisely even though these are differing in magnitude and direction depending on the vehicle (Passenger car or Heavy duty).
A number of different approaches and technologies have recently been proposed in order to utilize exhaust and coolant heat. The scope of utilization reaches from the conservation heat in order to avoid cold starts or to increase the temperature for these to the generation of electricity.
Main drive train hybridisation is not considered in this paper.
Depending on the layout and dimensioning of drive train and vehicle and the envisaged operational strategy the technical potential for utilising the above mentioned energy flows will be assessed and described and appropriate technologies for their utilisation will be identified. Basis for comparison according to technical and commercial criteria is discussed.
Technologies considered (given here without any particular order) will include: Steam cycles (ORC); Gas cycles, Joule, Stirling, Ericsson; Turbo compounding; Electro-chemical and Semiconductor based devices, FC-APU, Seebeck Effect and AMTEC.
In some cases competition between some of these technologies has existed in other fields of application e.g. aerospace or defence. Some reference is made to these cases.