Parallel Session: Operational Experience I
CLEAN CYCLE™ – WASTE-HEAT-RECOVERY TECHNOLOGY
Abstract: Clean Cycle™, from GE Energy, adapts Organic Rankine Cycle (ORC) technology for the vast majority of smaller-scale heat-wasting processes. Clean Cycle takes waste heat from sources as low as 250°F (121°C) and transforms it into 125 kW of electricity for the renewable and distributed energy segments.
An integrated Power Module (IPM) is the heart of the Clean Cycle system and houses the high speed turbine and generator. Magnetic bearings that support the turbine and rotor facilitate the shaft spinning in a magnetic field rather than riding on a mechanical bearing. The bearings require no lubrication systems, and the entire generator and turbine are hermetically sealed so external seals are not required, either. Clean Cycle’s Power Electronics convert the raw power generated at the IPM to usable electricity at the exact same frequency and voltage as the grid to which the IPM is attached -- without gearboxes or other mechanical means. The power generated has a constant power factor of 1, so costly capacitors are not needed.
Clean Cycle can operate in small spaces, be moved from site to site, and accommodate a broad range of facilities, including factories, foundries and cement plants.
To utilize Clean Cycle, waste heat must be exclusively available, with no diversion to other purposes such as heating water. The number of engines determines the type of installation. Customers have the option of installing a collection of smaller engines to combine their accumulated waste heat.
BACKGROUND AND SUMMARY OF COMMERCIAL ORC
Antti Uusitalo, Jaakko Larjola, Teemu Turunen-Saaresti
The first Organic Rankine Cycle (ORC) power plants were built at the beginning of the 1960s and
the principle of ORC process has been known for decades. The majority of the early ORC plants
were built between 60’s and 80’s. Excluding chloro-fluoro-carbons, the most popular working
fluids at that time were chlorobenzenes, fluorinol 85 and toluene.
Nowadays the most ORC applications are related to produce electricity and heat from biomass,
industrial waste heat, geothermal heat and solar power. In the early stages of the commercialization
there were only few manufactures and during the 90’s and the beginning of millennium only very
few ORC plants were realized. However, the interest towards the ORC has been raised recently, and
there have been many new manufacturers coming on markets during the last decade. The number of
delivered ORC units and installed power worldwide has increased rapidly and several hundred ORC
plants have been built during the last decade. Also a wide range of more suitable and environmental
friendly working fluids have been adapted for the commercial ORC plants compared to the earliest
The tightening of the greenhouse gas emission regulations have set the goals and the limits for the
use of energy efficient processes and better fuel economy in both large and small scale energy
production systems. Nowadays, it is very important to decrease CO2 and CH4 emissions having an
effect on the global warming. CH4-rich gases, (biogas, landfill gas) produced by the decay of
organic material and biomass, can be exploited in distributed electricity and heat production.
Utilizing the waste heat streams from the industrial processes in electricity and heat production is a
suitable way to achieve improvements to the energy efficiency of the processes and reducing CO2
emissions. In these kinds of applications the ORC technology is a feasible choice due to its flexible
power range and therefore, it is expected that the number of installed ORC plants will increase
rapidly in the near future.
 Larjola J. “Organic Rankine cycle (ORC) based waste heat / waste fuel recovery systems for
small CHP applications”. Chapter 9 in: Small- and micro-combined heat and power (CHP)
systems, Advanced design, performance, materials and applications. Editor: Robert Beith, 528 p.
Woodhead Publishing Limited, Oxford 2011
 Quoilin S., Lemort V. “Technological and Economical Survey of Organic Rankine Cycle
Systems” 5th European conference Economics and Management of Energy in Industry, Algarve
Portugal, April 14 – 17, 2009
ORGANIC RANKINE CYCLES FOR GEOTHERMAL APPLICATIONS
Abstract: Organic Rankine Cycles for Geothermal Applications
Ormat Technologies, Inc.
e-mail: Ukaplan @ormat.com
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.
 Bronicki, L.Y., 1989, “Organic Vapor Turbogenerators using Locally Available Heat Sources – 25 Years of Industrial Experience”, Congress of the World Energy Conference, Montreal
 Bronicki, L.Y., 1994, “Innovative Geothermal and Heat Recovery Power Plants Experience to Date”, CEPSI, New Zealand
 Bronicki, L.Y., 2002, “Geothermal Power Stations”, Encyclopedia of Physical Science and Technology, Third Editions, 6, Academic Press, San Diego
 DiPippo, R., 2004, “Second Law Assessment of Binary Plants Generating Power from Low-Temperature Geothermal Fluids”, Geothermics, University of Massachusetts, Dartmouth, USA
 Bronicki, L.Y., “Implementing New Power Plant Technologies, Technical and Economic Aspects”, Geothermal Energy and Territory Conference, Pomarance, Tuscany, Italy, 2004
 Bronicki, L.Y., “Advanced Power Cycles for Enhancing Geothermal Sustainability”, IEEE, Pittsburg 2008