Organic Rankine cycle coupled to a solar pond by direct-contact heat exchange - selection of a working fluid

Technical Report · Tue Jun 01 00:00:00 EDT 1982

OSTI ID:6918926

Wright, J D

Heat from a solar pond may be used to drive an organic Rankine cycle and produce electricity. Due to the inherent low efficiency of low-temperature cycles, large amounts of heat must be transferred, and heat exchangers may account for up to 50% of the plant cost. Use of a direct-contact boiler, in which the organic fluid is bubbled through a stream of pond brine, may reduce the plant cost by about 25%. The choice of a working fluid affects plant efficiency, turbine cost, and the loss rate of the organic fluid. Low-vapor-pressure fluids maximize cycle efficiency by minimizing pumping requirements, but require a larger turbine. Because efficiency affects the size and cost of the entire plant, low-pressure fluids are preferred. Both the saturated and halogenated hydrocarbons were evaluated for use as working fluids. Pentane was the working fluid best suited to this application, because it showed high efficiency, low solubility in the pond, and a reasonable turbine cost.

• Research Organization: Solar Energy Research Inst., Golden, CO (USA)
• DOE Contract Number: AC02-77CH00178
• OSTI ID: 6918926
• Report Number(s): SERI/TR-631-1122R; ON: DE82020998
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
RANKINE CYCLE POWER SYSTEMS
DIRECT CONTACT HEAT EXCHANGERS
SOLAR PONDS
WORKING FLUIDS
SOLAR THERMAL POWER PLANTS
2-METHYLPROPANE
ALKANES
BRINES
COST
EFFICIENCY
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
LOSSES
PENTANE
REFRIGERANTS
SALINITY GRADIENTS
SOLUBILITY
THERMODYNAMICS
ENERGY SYSTEMS
EQUIPMENT
FLUIDS
HEAT EXCHANGERS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PONDS
POWER PLANTS
POWER SYSTEMS
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR POWER PLANTS
SURFACE WATERS
THERMAL POWER PLANTS
140700* - Solar Thermal Power Systems
141000 - Solar Collectors & Concentrators