Use and limitations of ASHRAE solar algorithms in solar energy utilization studies
Conference
·
· ASHRAE J.; (United States)
OSTI ID:6152234
Algorithms for computer calculation of solar radiation based on cloud cover data, recommended by the ASHRAE Task Group on Energy Requirements for Buildings, are examined for applicability in solar utilization studies. The implementation is patterned after a well-known computer program, NBSLD. The results of these algorithms, including horizontal and tilted surface insolation and useful energy collectable, are compared to observations and results obtainable by the Liu and Jordan method. For purposes of comparison, data for Riverside, CA from 1960 through 1963 are examined. It is shown that horizontal values so predicted are frequently less than 10% and always less than 23% in error when compared to averages of hourly measurements during important collection hours in 1962. Average daily errors range from -14 to 9% over the year. When averaged on an hourly basis over four years, there is a 21% maximum discrepancy compared to the Liu and Jordan method. Corresponding tilted-surface discrepancies are slightly higher, as are those for useful energy collected. Possible sources of these discrepancies and errors are discussed. Limitations of the algorithms and various implementations are examined, and it is suggested that certain assumptions acceptable for building loads analysis may not be acceptable for solar utilization studies. In particular, it is shown that the method of separatingg diffuse and direct components in the presence of clouds requires careful consideration in order to achieve accuracy and efficiency in any implementation.
- Research Organization:
- California State Univ., Fullerton
- OSTI ID:
- 6152234
- Conference Information:
- Journal Name: ASHRAE J.; (United States) Journal Volume: 84:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hourly Solar Radiation Data for Vertical and Horizontal Surfaces on Average Days in the United States and Canada
Guide for calculating collection efficiency for the shallow solar pond (applicable for any horizontal flat plate solar collector)
Hourly vs daily method of computing insolation on inclined surfaces
Technical Report
·
Thu Mar 31 23:00:00 EST 1977
·
OSTI ID:5267143
Guide for calculating collection efficiency for the shallow solar pond (applicable for any horizontal flat plate solar collector)
Technical Report
·
Fri Feb 01 00:00:00 EDT 1974
·
OSTI ID:4331019
Hourly vs daily method of computing insolation on inclined surfaces
Journal Article
·
Sat Dec 31 23:00:00 EST 1977
· Sol. Energy; (United States)
·
OSTI ID:6342427