RECOVERY OF WASTE HEAT BY MEANS OF ORGANIC FLUID

After finding that Fluorinol 85 (F-85), a non-flammable non-toxic organic fluid with a low boiling-point (76.1 deg C), was excellent for use in the conversion (by expansion of the vapour through a turbine) of heat energy into mechanical power, especially when the heat source has a comparatively low temperature, the Thermo Electron Corporation (TECO) developed the Organic Rankine Cycle System (ORCS), which uses F-85 as its working fluid. In 1976, Mitsui Engineering & Shipbuilding concluded an agreement with TECO, and using the basic ORCS technique in association with their own techniques for waste-heat recovery, Mitsui have been developing a 500-kW experimental electricity-generating plant for utilising waste heat; information on trials, at a steel mill, of this plant is expected to be available soon. The Authors, of Mitsui, describe and discuss the characteristics of F-85 fluid and of the ORCS in some detail, with special reference to its potential for marine applications; an explanation of the relevant theory is included. The source of the waste heat can be the exhaust of a main or auxiliary Diesel engine or gas turbine. The particular value of the system is that it enables waste heat at about 200 deg to 500 deg C (typical of many Diesel-engine exhausts) to provide power, for electricity generation or to assist propulsion, with a high degree of efficiency; waste heat at these temperatures has hitherto been lost owing to the lack of an effective working fluid. The system would enable a Diesel engine of, say, 10,000 to 13,500 hp to provide power for turbo-generator drive, whereas the engine would need to be one of, say, 13,500 to 18,000 hp before a steam cycle would be practicable. Its efficiency results in 10 to 30% more power than a steam cycle, from a 250 deg to 500 deg C heat-source; above 500 deg C, it loses this superiority. Features of the system include a once-through vapour-generator, a compact turbine, low turbine-speed, and a regenerator for preheating the working fluid. The article includes a number of flow and other diagrams illustrating the principles and performance of the system. It is mentioned that, in some applications, a working fluid with a lower boiling point than F-85, such as Freon-11 or pentane, may be desirable. Order from BSRA as No. 49,660.

  • Corporate Authors:

    Marine Engineering Society in Japan

    Osaka Building, 1-2-2 Uchisaiwai-Cho, Chiyoda-Ku
    Tokyo 100,   Japan 
  • Authors:
    • Ohashi, S
    • Suzuki, T
  • Publication Date: 1978

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Filing Info

  • Accession Number: 00195358
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jul 31 1979 12:00AM