Masoud Soltani- Hosseini - Mechanical Eng Department, Niroo Research Institute, lran.
Hallgimur Sigurdsson - Rafhonnun Consulting Engineers Annula ۴۲, ۱۰۸ Reykjavik, Iceland.

Co-generation power plant is one of the alternatives for the first geothermal plant in die Sabalan area. This kind of power plant combines electricity generation with direct heat applications. The latter can be accomplished using the thermal energy available in the waste brine and rejected heat from die condenser to heat fresh feed, water which can then be distributed to a variety of end users. Design parameters and performance charac teris ties of this kind of power plant is studied in this paper. Results show that [lie utilization efficiency of geothermal co-generation power plants is 15-45% depending on the enthalpy and scaling potential of the geothermal fluid and also die electrical and heat loads of district heating system. The energy balance of this type of geothermal power plants is also presented in this paper. A technical and economic assessment is necessary to determine the optimum electrical and thermal output of a geothermal cogeneration -power plant according to the properties of the geothermal fluid and local energy and economic parameters.

co-generation, geothermal, design, power plant