This paper presents a study aimed at evaluating the use of siloxanes as the working fluid of a small-capacity () ORC turbogenerator based on the “high-speed technology” concept, combining the turbine, the pump, and the electrical generator on one shaft, whereby the whole assembly is hermetically sealed, and the bearings are lubricated by the working fluid. The effects of adopting different siloxane working fluids on the thermodynamic cycle configuration, power output, and on the turbine and component design are studied by means of simulations. Toluene is included into the analysis as a reference fluid in order to make comparisons between siloxanes and a suitable low molecular weight hydrocarbon. The most influential working fluid parameters are the critical temperature and pressure, molecular complexity and weight, and, related to them, the condensation pressure, density and specific enthalpy over the expansion, which affect the optimal design of the turbine. The fluid thermal stability is also extremely relevant in the considered applications. Exhaust gas heat recovery from a 120 kW diesel engine is considered in this study. The highest power output, 13.1 kW, is achieved with toluene as the working fluid, while, among siloxanes, provides the best simulated performance, namely 10.9 kW. The high molecular weight of siloxanes is beneficial in low power capacity applications, because it leads to larger turbines with larger blade heights at the turbine rotor outlet, and lower rotational speed if compares, for instance, to toluene.
Siloxanes as Working Fluids for Mini-ORC Systems Based on High-Speed Turbogenerator Technology
Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the Journal of Engineering for Gas Turbines and Power. Manuscript received February 28, 2012; final manuscript received June 25, 2012; published online March 18, 2013. Assoc. Editor: Joost J. Brasz.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Uusitalo, A., Turunen-Saaresti, T., Honkatukia, J., Colonna, P., and Larjola, J. (March 18, 2013). "Siloxanes as Working Fluids for Mini-ORC Systems Based on High-Speed Turbogenerator Technology." ASME. J. Eng. Gas Turbines Power. April 2013; 135(4): 042305. https://doi.org/10.1115/1.4023115
Download citation file:
- Ris (Zotero)
- Reference Manager