The impact of component performance on the overall cycle performance of small-scale low temperature organic Rankine cycles

Low temperature organic Rankine cycles offer a promising technology for the generation of power from low temperature heat sources. Small-scale systems (~10kW) are of significant interest, however there is a current lack of commercially viable expanders. For a potential expander to be economically viable for small-scale applications it is reasonable to assume that the same expander must have the ability to be implemented within a number of different ORC applications. It is therefore important to design and optimise the cycle considering the component performance, most notably the expander, both at different thermodynamic conditions, and using alternative organic fluids. This paper demonstrates a novel modelling methodology that combines a previously generated turbine performance map with cycle analysis to establish at what heat source conditions optimal system performance can be achieved using an existing turbine design. The results obtained show that the same turbine can be effectively utilised within a number of different ORC applications by changing the working fluid. By selecting suitable working fluids, this turbine can be used to convert pressurised hot water at temperatures between 360K and 400K, and mass flow rates between 0.45kg/s and 2.7kg/s, into useful power with outputs between 1.5kW and 27kW. This is a significant result since it allows the same turbine to be implemented into a variety of applications, improving the economy of scale. This work has also confirmed the suitability of the candidate turbine for a range of low temperature ORC applications

ORMAT qualifications and work experience

Overview, group of companies, projects, engineering, project management, corporate resumes, fact sheets

Dr. House: medical ethics and subjective responsibility

House’s first season premiered in November, 2004 and ended in 2012. Millions of people have enjoyed these 8 seasons over nearly a decade. Different conjectures have been put forward to try to explain the magnitude of the show’s success, giving way to various newspaper and philosophical articles. This study, which is part of a research program on Cinema and Ethics of the University of Buenos Aires, proposes three lines of analysis: (a) philosophical cynicism as the outstanding feature in House’s interventions – his swing from irony and sarcasm to total lucidity; (b) the underlying ethical concept in his medical interventions –read in terms of the French philosopher Alain Badiou; (c) the two dimensions of responsibility that are present in the series in different episodes –legal deontological responsibility and subjective responsibility, read in terms of French psychoanalyst Jacques Lacan. In order to do this, several passages from five different episodes of ‘House’ are taken, centering the analysis on one of them, where both ethical cynicism and the tension between the two dimensions of responsibility are concentrated

Kapoho State 2 well

Date Range: 1987-1990Documents include letters between ORMAT and DLNR, applications for permits, and figures

The Application of Similitude Theory for the Performance Prediction of Radial Turbines Within Small-Scale Low-Temperature Organic Rankine Cycles

For small-scale organic Rankine cycles (ORCs) to be a competitive technology, it is reasonable to assume that the same turbine design will be implemented into a range of different applications. It is therefore critical to be able to predict turbine off-design performance over a range of different operating conditions while utilizing different working fluids. Similitude theory can be used for this purpose, and it has been well validated for ideal gases. However, the same cannot be said for its applications to the organic fluids found within ORCs. This paper considers a candidate subsonic turbine design operating with R245fa and the corresponding turbine performance map. Similitude theory is used to predict the performance of the same turbine operating at different inlet conditions using R245fa, R123, and R1234yf. The similitude predictions are compared to computational fluid dynamics (CFD) results obtained using ansys CFX. The original similitude theory using turbine total inlet conditions was found to only apply within a small range of operating conditions, so a modified similitude theory has been suggested that uses the choked flow conditions instead. This modified similitude theory agrees with the CFD predictions to within 2%, right up until the choked mass flow rate. Further studies considering supersonic turbines are required to establish the applicability of similitude for applications beyond the choked pressure ratio