Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering


Sobiesiak, Andrzej




As emissions regulations become more stringent, automakers must improve fuel consumption in their vehicles to meet performance targets. An Organic Rankine Cycle is a technology with substantial fuel savings potential. As the power producing device in the system, the expander is a critical component with a large impact on overall cycle efficiency. The choice of expander type can significantlly affect system design choices. In order to decrease development time, a modeling tool which can evaluate the performance of various expander types is necessary to simulate expander performance without the need for costly prototyping and testing. This thesis will examine the development of a generic Matlab expander model which can replicate expander performance through a thermodynamic analysis. A modular approach to modeling allows for differentiation between expander types and sizes through modification of user defined modules. Thermal behaviour of the device is examined with an emphasis on heat transfer and its effect on expander performance. Results of the model and applications including the system response to thermal conditions are examined in detail.