Selection and Conversion of Turbocharger as Turbo-expander for Organic Rankine Cycle (orc)

Turbo-expander is the most crucial and expensive component in Organic Rankine Cycle (ORC) power generation systems. The turbine engineering, design and research development process for ORC system is costly, time-consuming, and difficult for new-entrants in the ORC field. This paper investigates the re-design and retrofit of an off-the-shelf turbocharger for use in a 1 kW ORC system. The expander requirements were determined for the 1 kW Capstone Gas Turbine bottoming cycles from the ORC system design. A radial turbine was selected and an off-theshelf turbocharger from a small petrol-driven vehicle was acquired. The turbocharger was simulated to study the offdesign performance in an ORC system. The turbocharger was evaluated by expansion of compressed air at room temperature to assess the leakage of working fluid and the lubrication requirements. A preliminary design was developed to deal with leakage and lubrication issues. The conceptual design of an ORC turbine was presented including the casing design and selection of auxiliary components such as bearings, seals and lubrication systems.