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Title: Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge

Abstract

Experimental and theoretical comparisons were made of the performance of cylindrical parabolic and flat plate solar energy collectors operating under Oak Ridge weather conditions. The flat plate collector was observed to consistently out-perform the parabolic collector under the design and operating (135 to 185/sup 0/F) conditions used (parabolic cylindrical collector - one glass cover plate, refocused hourly, receiver absorptivity of 0.87; flat plate collector - two glass cover plates oriented at latitude minus declination, absorptivity 0.98). Other factors contributed to the difference including poorer insulation (1.25 in. fiberglass) for the focusing collector (versus 5 in. fiberglass for the flat plate) and a poor fin efficiency for the receiver tube of the focusing collector. Observed efficiencies were as high as 47% for the cylindrical parabolic collector operating with one glass plate at 185/sup 0/F and as high as 62% for the flat plate collector operating with two glass plates at 165/sup 0/F. Performance models were developed for both collectors and the model used for the flat plate collector was extended to predict month-to-month operation under Oak Ridge weather conditions (based on the average of 16 years of weather data). A temperature distribution model was developed for optimization of the finned tubemore » receiver used in the cylinderical parabolic collector. Further experimentation should be conducted at higher temperatures (approx. 250/sup 0/F) with selective receiver coatings (..cap alpha../epsilon >> 1) and also runs under conditions of broken cloud cover are suggested. In addition, the performance models should be extended and the finned tube design optimization continued.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Massachusetts Inst. of Tech., Oak Ridge, TN (USA). School of Chemical Engineering Practice
OSTI Identifier:
5477479
Report Number(s):
ORNL-MIT-192
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; FLAT PLATE COLLECTORS; PERFORMANCE; PARABOLIC TROUGH COLLECTORS; CLOUD COVER; COMPARATIVE EVALUATIONS; DAILY VARIATIONS; FINS; MATHEMATICAL MODELS; MONTHLY VARIATIONS; OAK RIDGE; OPERATION; OPTIMIZATION; SEASONAL VARIATIONS; TEMPERATURE DISTRIBUTION; TUBES; WORKING FLUIDS; CONCENTRATING COLLECTORS; EQUIPMENT; FLUIDS; NORTH AMERICA; PARABOLIC COLLECTORS; SOLAR COLLECTORS; SOLAR EQUIPMENT; SOUTHEAST REGION; TENNESSEE; USA; VARIATIONS; 141000* - Solar Collectors & Concentrators

Citation Formats

Kronenberger, E. J., Newman, J. S., Demetriou, C. V., and Orlandi, R. D. Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge. United States: N. p., 1974. Web. doi:10.2172/5477479.
Kronenberger, E. J., Newman, J. S., Demetriou, C. V., & Orlandi, R. D. Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge. United States. https://doi.org/10.2172/5477479
Kronenberger, E. J., Newman, J. S., Demetriou, C. V., and Orlandi, R. D. 1974. "Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge". United States. https://doi.org/10.2172/5477479. https://www.osti.gov/servlets/purl/5477479.
@article{osti_5477479,
title = {Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge},
author = {Kronenberger, E. J. and Newman, J. S. and Demetriou, C. V. and Orlandi, R. D.},
abstractNote = {Experimental and theoretical comparisons were made of the performance of cylindrical parabolic and flat plate solar energy collectors operating under Oak Ridge weather conditions. The flat plate collector was observed to consistently out-perform the parabolic collector under the design and operating (135 to 185/sup 0/F) conditions used (parabolic cylindrical collector - one glass cover plate, refocused hourly, receiver absorptivity of 0.87; flat plate collector - two glass cover plates oriented at latitude minus declination, absorptivity 0.98). Other factors contributed to the difference including poorer insulation (1.25 in. fiberglass) for the focusing collector (versus 5 in. fiberglass for the flat plate) and a poor fin efficiency for the receiver tube of the focusing collector. Observed efficiencies were as high as 47% for the cylindrical parabolic collector operating with one glass plate at 185/sup 0/F and as high as 62% for the flat plate collector operating with two glass plates at 165/sup 0/F. Performance models were developed for both collectors and the model used for the flat plate collector was extended to predict month-to-month operation under Oak Ridge weather conditions (based on the average of 16 years of weather data). A temperature distribution model was developed for optimization of the finned tube receiver used in the cylinderical parabolic collector. Further experimentation should be conducted at higher temperatures (approx. 250/sup 0/F) with selective receiver coatings (..cap alpha../epsilon >> 1) and also runs under conditions of broken cloud cover are suggested. In addition, the performance models should be extended and the finned tube design optimization continued.},
doi = {10.2172/5477479},
url = {https://www.osti.gov/biblio/5477479}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 22 00:00:00 EDT 1974},
month = {Wed May 22 00:00:00 EDT 1974}
}