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U.S. Department of Energy
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User manual for GEOCOST: a computer model for geothermal cost analysis. Volume 2. Binary cycle version

Technical Report ·
DOI:https://doi.org/10.2172/7140516· OSTI ID:7140516

A computer model called GEOCOST has been developed to simulate the production of electricity from geothermal resources and calculate the potential costs of geothermal power. GEOCOST combines resource characteristics, power recovery technology, tax rates, and financial factors into one systematic model and provides the flexibility to individually or collectively evaluate their impacts on the cost of geothermal power. Both the geothermal reservoir and power plant are simulated to model the complete energy production system. In the version of GEOCOST in this report, geothermal fluid is supplied from wells distributed throughout a hydrothermal reservoir through insulated pipelines to a binary power plant. The power plant is simulated using a binary fluid cycle in which the geothermal fluid is passed through a series of heat exchangers. The thermodynamic state points in basic subcritical and supercritical Rankine cycles are calculated for a variety of working fluids. Working fluids which are now in the model include isobutane, n-butane, R-11, R-12, R-22, R-113, R-114, and ammonia. Thermodynamic properties of the working fluids at the state points are calculated using empirical equations of state. The Starling equation of state is used for hydrocarbons and the Martin-Hou equation of state is used for fluorocarbons and ammonia. Physical properties of working fluids at the state points are calculated.

Research Organization:
Battelle Pacific Northwest Labs., Richland, Wash. (USA)
DOE Contract Number:
E(45-1)-1830
OSTI ID:
7140516
Report Number(s):
BNWL-1942-V2
Country of Publication:
United States
Language:
English