Waste heat rejection from geothermal power stations

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6031269

Robertson, R C

Waste heat rejection systems for geothermal power stations have a significantly greater influence on plant operating performances and costs than do corresponding systems in fossil- and nuclear-fueled stations. With thermal efficiencies of only about 10%, geothermal power cycles can reject four times as much heat per kilowatt of output. Geothermal sites in the United States tend to be in water-short areas that could require use of more expensive wet/dry or dry-type cooling towers. With relatively low-temperature heat sources, the cycle economics are more sensitive to diurnal and seasonal variations in sink temperatures. Factors such as the necessity for hydrogen sulfide scrubbers in off-gas systems or the need to treat cooling tower blowdown before reinjection can add to the cost and complexity of goethermal waste heat rejection systems. Working fluids most commonly considered for geothermal cycles are water, ammonia, Freon-22, isobutane, and isopentane. Both low-level and barometric-leg direct-contact condensers are used, and reinforced concrete has been proposed for condenser vessels. Multipass surface condensers also have wide application. Corrosion problems at some locations have led to increased interest in titanium tubing. Studies at ORNL indicate that fluted vertical tubes can enhance condensing film coefficients by factors of 4 to 7.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: Not Available; USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6031269
• Report Number(s): CONF-790808-16
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150802* -- Geothermal Power Plants-- Power Plant Systems & Components
2-METHYLPROPANE
ALKANES
AMMONIA
CHEMICAL REACTIONS
CONDENSERS
COOLING TOWERS
CORROSION
EFFICIENCY
ELEMENTS
ENERGY
ENERGY SOURCES
FLASHED STEAM SYSTEMS
FLUIDS
FREONS
GEOTHERMAL POWER PLANTS
HALOGENATED ALIPHATIC HYDROCARBONS
HEAT
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
MECHANICAL DRAFT COOLING TOWERS
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PENTANE
PERFORMANCE
POWER PLANTS
REFRIGERANTS
REINJECTION
THERMAL EFFICIENCY
THERMAL POWER PLANTS
TITANIUM
TRANSITION ELEMENTS
WASTE HEAT
WASTES
WORKING FLUIDS