Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients
Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients Dan Wendt, Greg Mines Idaho National Laboratory The use of mixed working fluids in binary power plants can provide significant increases in plant performance, provided the heat exchangers are designed to take advantage of these fluids non-isothermal phase changes. In the 1980's testing was conducted at DOE's Heat Cycle Research Facility (HCRF) where mixtures of different compositions were vaporized at supercritical pressures and then condensed. This testing had focused on using the data collected to verify that Heat Transfer Research Incorporated (HTRI) codes were suitable for the design of heat exchangers that could be used with mixtures. The HCRF data includes mixture compositions varying from 0% to 40% isopentane and condenser tube orientations of 15{sup o}, 60{sup o}, and 90{sup o} from horizontal. Testing was performed over a range of working fluid and cooling fluid conditions. Though the condenser used in this testing was water cooled, the working fluid condensation occurred on the tube-side of the heat exchanger. This tube-side condensation is analogous to that in an air-cooled condenser. Tube-side condensing heat transfer coefficient information gleaned from the HCRF testing is used in this study to assess the suitability of air-cooled condenser designs for use with mixtures. Results of an air-cooled binary plant process model performed with Aspen Plus indicate that that the optimal mixture composition (producing the maximum net power for the scenario considered) is within the range of compositions for which data exist. The HCRF data is used to assess the impact of composition, tube orientation, and process parameters on the condensing heat transfer coefficients. The sensitivity of the condensing coefficients to these factors is evaluated and the suitability of air-cooled condenser designs with mixtures is assessed. This paper summarizes the evaluation of the HCRF data and discusses the next steps in the project evaluation of air-cooled condenser designs that can take advantage of the performance gains possible with these fluids.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - EE
- DOE Contract Number:
- DE-AC07-05ID14517
- OSTI ID:
- 1044204
- Report Number(s):
- INL/CON-11-21392; TRN: US201214%%371
- Resource Relation:
- Conference: Geothermal Resources Council Annual Meeting,San Diego, California,10/23/2011,10/26/2011
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
2-METHYLBUTANE
DESIGN
EVALUATION
GEOTHERMAL RESOURCES
HEAT EXCHANGERS
HEAT TRANSFER
IDAHO NATIONAL LABORATORY
MIXTURES
ORIENTATION
PERFORMANCE
POWER PLANTS
SENSITIVITY
TESTING
WATER
WORKING FLUIDS
binary cycles
condenser
heat transfer
heat transfer coefficients
working fluid mixtures