Working fluid and cycle selection criteria for binary geothermal power plants with resource temperatures in the range of 220/sup 0/F to 400/sup 0/F

Technical Report · Fri Apr 01 04:00:00 EST 1977

OSTI ID:7213980

Ingvarsson, I J; Turner, S E

Binary cycles using refrigerants as working fluids are an effective means of developing geothermal resources for power production. In order to maximize the utilization of the geothermal fluid resource over a temperature range of from 220/sup 0/F to 400/sup 0/F, a study was performed to optimize plant design with respect to working fluid and thermodynamic cycle. Additionally, system variations due to tolerances applied to key plant input factors are included for each optimum fluid-cycle combination. Four working fluids were considered in this study: isobutane, pentane, propane and Genetron 31/114 (an azeotrope of Genetron 31 and Genetron 114 developed by Allied Chemical Corporation). Isobutane, pentane, and propane are hydrocarbons, whereas Genetron 31/114 is a halogen. The parametric studies indicated that hydrocarbons were better working fluids for the binary system than were halogens. Genetron's behavior was similar to that of isobutane's but never equaled its performance. It is, however, nonexplosive, noncombustible, and relatively nontoxic, whereas the hydrocarbons are explosively combustible, and highly toxic. At some trade-off point, then, system safety may become more important than optimum cycle performance. The propane cycles controlled the optimum performance for g.f. temperatures of 220/sup 0/F to 280/sup 0/F. For a g.f. temperature range of 300/sup 0/F to 360/sup 0/F the isobutane cycles performed highest, and for g.f. temperatures of 380/sup 0/F to 400/sup 0/F, the pentane cycles were the most effective. For temperatures near the change of control points for the fluids, a mixture of fluids is recommended. The effectiveness of the system would thus be protected in case of resource degradation.

• Research Organization: Idaho Coll., Caldwell (USA). Snake River Regional Studies Center
• DOE Contract Number: EY-76-C-07-1570
• OSTI ID: 7213980
• Report Number(s): TREE-1108
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150802* -- Geothermal Power Plants-- Power Plant Systems & Components
2-METHYLPROPANE
ALKANES
BINARY-FLUID SYSTEMS
COMPARATIVE EVALUATIONS
COMPUTER CALCULATIONS
DIAGRAMS
DISPERSIONS
ELEMENTS
FLOWSHEETS
FLUID FLOW
FLUIDS
GEOTHERMAL POWER PLANTS
HALOGENS
HYDROCARBONS
MEDIUM TEMPERATURE
MIXTURES
NONMETALS
OPTIMIZATION
ORGANIC COMPOUNDS
PENTANE
PERFORMANCE TESTING
POWER PLANTS
PROPANE
SAFETY
TESTING
THERMAL POWER PLANTS
THERMODYNAMIC CYCLES
WORKING FLUIDS