Hourly diffuse fraction correlation at a tropical location

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Solar Energy (Journal of Solar Energy Science and Engineering); (United States)

DOI:https://doi.org/10.1016/0038-092X(94)90130-T· OSTI ID:6776465

Chandrasekaran, J; Kumar, S ^[1]

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1. Madurai Kamaraj Univ. (India)

Five years of hourly global and diffuse radiation data on a horizontal surface at a tropical location (Madras, India) were used to establish the relationship between the hourly diffuse fraction and hourly clearness index. Two types of correlations--on a yearly and a seasonal (wet and dry months)--have been established. Piecewise and single polynomial curves have been fitted to the data. These correlations have been compared to those developed by Orgill and Hollands, Erbs el al., and Reindl et al., which have been obtained from data of temperate locations. The comparison has been performed in terms of standard deviation and relative standard deviation. The results indicate that the proposed correlations are better. The best fits were obtained when the seasonal effects were taken into account. It is also shown that the hourly diffuse fraction is larger at a tropical location at higher hourly clearness indices.

• OSTI ID: 6776465
• Journal Information: Solar Energy (Journal of Solar Energy Science and Engineering); (United States), Journal Name: Solar Energy (Journal of Solar Energy Science and Engineering); (United States) Vol. 53:6; ISSN SRENA4; ISSN 0038-092X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140100* -- Solar Energy-- Resources & Availability
CALCULATION METHODS
CLOUD COVER
CORRELATIONS
DIFFUSE SOLAR RADIATION
RADIATIONS
SEASONAL VARIATIONS
SOLAR FLUX
SOLAR RADIATION
STELLAR RADIATION
TROPICAL REGIONS
VARIATIONS