Proceedings of the
5th International Seminar on
ORC Power Systems
9 - 11 September 2019, Athens Greece
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Design of an Experimental ORC Expander Setup Using Natural Working Fluids

Go-down orc2019 Tracking Number 43

Session: Poster session and Ouzo tasting in room Kallirhoe
Room: ---
Session start: 17:20 Mon 09 Sep 2019

Ángel Á. Pardiñas

Marcin Pilarczyk

Lars O. Nord

Roberto Agromayor

Topics: - Experimental activities and techniques (Topics), - Poster Presentation (Preferred Presentation type)


Organic Rankine Cycles (ORCs) are a potential solution to recover energy and generate power from surplus heat that different industries, such as metal production and the oil and gas industry in Norway, are currently releasing to the ambient. The industries are often in remote locations, which complicates direct use of the heat. The expander is a crucial component in any ORC system since it transforms the energy of the working fluid into shaft power. This potential for waste heat recovery, combined with the future restrictions on some of the fluids normally used in these units, justify the need for further research on ORC expanders using natural working fluids, such as hydrocarbons. To the knowledge of the authors, there is no experimental data available in the open literature for flows involving natural working fluids and operating conditions representative of ORC expanders. As a result, the fluid dynamic design methodologies used for ORC expanders often rely on tools that have not been validated. In response to this lack of experimental data, a test rig to characterize the performance of expanders in the 100 kW range will be designed and built at NTNU. This unit, named Expander Test Rig, is a part of the infrastructure project HighEFF-Lab, sponsored by The Research Council of Norway. In this work, the design of the Expander Test Rig is presented. The experimental setup design aims to be flexible enough to study the performance of both turbo- and volumetric expanders operating with different natural working fluids and their mixtures, at various operating conditions. To cover a range of operating conditions relevant for industrial applications, the test rig was designed for electrical power outputs between 30 and 50 kW, pressure ratios ranging from 2 to 8 and static temperatures at the inlet from 100 °C to 150 °C. In addition, the unit was designed to operate in the gas phase only to reduce the heating and cooling needs as well as the charge of working fluid, which is particularly important with hydrocarbons, the family of substances targeted in the design. A tailor-made, single-stage axial turbine operating with isobutane (R600a) was selected as the starting expander configuration.