SCRAM: a fast computational model for the optical performance of point fucus solar central receiver systems
Because of the complexities of heliostat shadowing and blocking calculations, computational models for the optical performance of point focus central receiver (PFCR) systems tend to be too slow for many important applications, such as optimization studies based on performance with realistic weather data. In this paper, a mathematical approximation procedure, designated Sandia Central Receiver Approximation Model (SCRAM) will be described. Rather than simulating the system components from first principles, it relies on data generated by the DELSOL code of Dellin and Fish for the optical performance of PFCR systems, and abstracts a mathematical model using a stepwise regression procedure. The result is a computational procedure which allows the user to define the heliostat field boundaries and tower height arbitrarily, generating a model for optical field performance, including shadowing, blocking, cosine, losses, and atmospheric attenuation, and which requires only a polynomial evaluation for each set of sun angles. A comparison with DELSOL for three different fields on three representative days indicates that the rms error of the approximation is 1-3% and that the new code is 1,000-3,000 times as fast as DELSOL. It is also shown that one reason that the accuracy in field performance predictions is higher than that of the generting function for the model is that much of the error in the generating function is due to an oscillatory behavior associated with a moire pattern in the optical response of the heiostat field.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5304143
- Report Number(s):
- SAND-80-0433
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CENTRAL RECEIVERS
MATHEMATICAL MODELS
COMPUTER CODES
S CODES
TOWER FOCUS COLLECTORS
ACCURACY
COMPUTER CALCULATIONS
HELIOSTATS
LOSSES
OPTICS
PERFORMANCE
REGRESSION ANALYSIS
SHADING
CONCENTRATING COLLECTORS
EQUIPMENT
MATHEMATICS
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR RECEIVERS
STATISTICS
CSP
Concentrating Solar Power
141000* - Solar Collectors & Concentrators
140702 - Solar Thermal Power Systems- Central Receiver