Organic Rankine Cycle based waste heat recovery modeling and control of the low pressure side using direct condensation and dedicated fans

Abstract

Organic Rankine cycle based waste heat recovery has been studied over the past decade as a potential solution to reduce fuel consumption and fulfill the requirements of upcoming regulations on CO2 emissions for heavy-duty trucks. This study, focusing on a particular configuration of the system, using direct condensation and dedicated fans, presents the models of all the components in the system and validation of the evaporator and fan model according to experimental results. A special attention has been paid to the effectiveness of the fan speed and condensation pressure control to increase the net power output of the direct condensed ORC. Road cycle simulations are run over an internal Volvo cycle that is suitable for the present application, using a "base" control strategy; afterwards a sensitivity analysis and optimization, involving the low pressure loop of the system, are performed, leading to better performance in terms of net power produced by the Rankine system.