Optimum for CO2 transcritical power Rankine cycle using exhaust gas from fishing boat diesel engines

We present a study of a carbon dioxide transcritical power Rankine cycle using exhaust gas from fishing boat diesel engine, in order to reduce fuel dependence. Two types of cycle have been studied: with or without internal heat exchanger. This work has been realised without defining the geometry of the heat exchangers. This choice means that their effectiveness is not considered.Results show that an optimal pressure is found for each temperature below 438K for systems without internal heat exchanger and for each temperature below 503K for systems that have one. Moreover, results show that an optimal temperature exists for each pressure in systems with internal heat exchanger. Those facts prove that an optimisation of this system is possible at design of heat exchangers, and this, in correlation with all other parts: pump, expander, etc. Furthermore, presence of those optimal conditions shows us possibility of a future system control that enables to stay at optimum despite exhaust gas variations.