The geothermal power generation will make a growing contribution to energy supply in
the future. Very important is the kind of the cycle, which is used for energy
supply. When the hot thermal water is directly relaxed from a temperature of circa
200 °C in the turbines, the secondary loop is used under this limit. For this
purpose the two technologies Kalina Cycle and Organic Rankine Cycle are available.
For the ORC there is more operational experience, but a higher efficiency of Kalina
cycle is assumed. Because the choice of the plant for power generation influences
the economies of geothermal projects, a clarification of the question, which type of
plant is advantageous for the energy recovery, has an immense importance. GEOCAL® is
one solution of ORC power plant with various possibilities. Every power plant has
its own boundary conditions, like temperature of geothermal water, cooling
conditions and utilization of heat. The most economic is not always the most
efficient geothermal power plant.
The presentation won’t solve all problems but will give some background information
and will show some possibilities for a better understanding in ORC technology.