Flat-plate solar-collector performance evaluation with a solar simulator as a basis for collector selection and performance prediction
- NASA Lewis Research Center, Cleveland, OH (United States)
The use of a solar simulator for performance determination permits collector testing under standard conditions of wind, ambient temperature, flow rate, and ''Sun.'' The performance results determined with the simulator have been found to be in good agreement with outdoor performance results. This paper reports the measured thermal efficiency and evaluation of 23 collectors which differ according to absorber material, absorber coating, type of glazing material, the use of honeycomb material and the use of vacuum to prevent thermal convection losses. The collectors are given performance rankings based on noon-hour solar conditions and all-day solar conditions. The determination with the simulator of an all-day collector performance is made possible by tests at different incident angles. The solar performance rankings are made based on whether the collector is to be used for pool heating, hot water, absorption air conditioning, heating, or for a solar Rankine machine. Another test which aids in selecting collectors is a collector heat capacity test. This test permits a ranking of collectors according to their heat capacity (and time constant), which is a measure of the rapidity of a collector's response to transient solar conditions. Results are presented for such tests. Final considerations for collector selection would of course be made on the basis of cost and the reliability of performance over the required life of a collector. Results of a cost-effectiveness study are given for conditions corresponding to those required for absorption a/c or heating. These results indicate that the additional cost involved in the upgrading of collector performance (selective surfaces, anti-reflection glass, etc.) appears to be cost effective and therefore justified. Some data are also presented to illustrate a method for the determination of outdoor performance degradation by use of simulator tests carried out before and after a period of outdoor operation.
- Research Organization:
- NASA Lewis Research Center, Cleveland, OH (United States)
- Sponsoring Organization:
- US Energy Research and Development Administration (ERDA)
- OSTI ID:
- 7186398
- Report Number(s):
- NASA-TM-X-71793; CONF-750712-15
- Journal Information:
- Solar Energy, Vol. 18, Issue 5; Conference: 1975 Annual Meeting of the International Solar Energy Society, Los Angeles, CA (United States), 28 Jul - 8 Aug 1975; ISSN 0038-092X
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
Determination of the optimum orientations for the double-exposure, flat-plate collector and its reflectors
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journal | October 1966 |
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