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Session: Parallel Session: Operational Experience I
Session starts: Thursday 22 September, 11:10
Presentation starts: 11:50
Room: Frans van Hasseltzaal

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Uri Kaplan ()

Abstract:
Organic Rankine Cycles for Geothermal Applications Uri Kaplan Ormat Technologies, Inc. e-mail: Ukaplan @ormat.com ABSTRACT Many innovative power cycles have been proposed in the past 20 years to widen the range of resources suitable for power generation beyond dry steam and flashed steam plants. During recent history, some (such as Kalina, Bi-Phase, etc.) have been experimented with, but only four are in commercial operation – single and double flash steam cycles, and two configurations of the Organic Rankine Cycle (ORC): the binary power cycle and geothermal combined cycle. The ORC has become the preferred means of exploiting low- to moderate-enthalpy geothermal and waste heat resources. The system has been widely used to efficiently and reliably utilize the brine in existing single flash geothermal plants, as well as with many other applications in the form of water only or water and low pressure steam. Over the years, the basic ORC has been improved and modified to adapt the cycle more efficiently to various heat source conditions. No single thermodynamic cycle provides a “cookie cutter” solution to all low- and medium-enthalpy cases. Adapting and combining the power cycles in the correct manner enables the optimal solution selection for specific resource conditions. An optimum power conversion cycle provides for the maximum output from an available heat source, while maintaining power plant simplicity combined with a high level of reliability. The optimization of the whole geothermal power plant system is accomplished by matching the working cycle and fluid properties to the characteristics of the resource, in considering not only the resulting efficiency and cost, but also the impact on the environment, the long-term pressure support requirements for make-up wells and the O&M costs. Operational experience has confirmed the advantages of the ORC plants, not only for the low enthalpy water dominated resources, but also at high enthalpy for aggressive brine or brine with high non condensable gas content. The somewhat higher installed cost of these systems is often justified by environmental and long-term resource management consideration. This presentation will describe advanced versions of the ORC and demonstrate their ability to provide an efficient conversion cycle adaptable to specific thermal and chemical properties in a wide variety of heat sources. REFERENCES [1] Bronicki, L.Y., 1989, “Organic Vapor Turbogenerators using Locally Available Heat Sources – 25 Years of Industrial Experience”, Congress of the World Energy Conference, Montreal [2] Bronicki, L.Y., 1994, “Innovative Geothermal and Heat Recovery Power Plants Experience to Date”, CEPSI, New Zealand [3] Bronicki, L.Y., 2002, “Geothermal Power Stations”, Encyclopedia of Physical Science and Technology, Third Editions, 6, Academic Press, San Diego [4] DiPippo, R., 2004, “Second Law Assessment of Binary Plants Generating Power from Low-Temperature Geothermal Fluids”, Geothermics, University of Massachusetts, Dartmouth, USA [5] Bronicki, L.Y., “Implementing New Power Plant Technologies, Technical and Economic Aspects”, Geothermal Energy and Territory Conference, Pomarance, Tuscany, Italy, 2004 [6] Bronicki, L.Y., “Advanced Power Cycles for Enhancing Geothermal Sustainability”, IEEE, Pittsburg 2008