Influence of condensation temperature and fluid properties on the organic Rankine cycle efficiency

The Organic Rankine Cycle (ORC) is becoming a popular choice for the exploitation of limited heat sources, where air and water cycles fail to provide satisfactory results. This paper gives a theoretical overview of the organic Rankine cycle and lists a number of its uses, highlighting its application in geothermal reservoirs, most commonly providing geothermal fluids in the liquid state. The advantages and disadvantages of this cycle are analyzed, followed by the criteria for fluid selection. Furthermore, a method for calculating the cycle efficiency of a specific geothermal ORC plant is presented, as well as an analysis of the impact that the condensation temperature and choice of working fluid have on the cycle efficiency. (author)