Estimation of the diffuse fraction of daily and monthly average global radiation for Fudhaliyah, Baghdad (Iraq)

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Solar Energy; (USA)

DOI:https://doi.org/10.1016/0038-092X(89)90132-1· OSTI ID:5165418

Al-Hamdani, N; Al-Riahi, M; Tahir, K ^[1]

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1. Scientific Research Council, Jadiriyah, (Iraq)

Separating the global solar radiation on a horizontal surface into direct and diffuse components is required in the simulation of solar energy systems. Many models have been developed for this purpose. The aim of this study is to establish, from the data collected over the period 1985-1986 at Fudhaliyah, daily correlations between (i) diffuse fraction of global radiation and clearness index; (ii) diffuse fraction and fractional sunshine duration; (iii) diffuse fraction and clearness index combined with fractional sunshine duration. In addition, the monthly average values of the above-mentioned correlations were established. Comparison with the most commonly used equation, Page's correlation, gives good agreement for monthly average of the relationship between diffuse fraction and clearness index. An equation for daily diffuse transmissivity values that incorporates a single physically based coefficient, which reflects the maximum clear-sky transmissivity at the study site is presented.

• OSTI ID: 5165418
• Journal Information: Solar Energy; (USA), Journal Name: Solar Energy; (USA) Vol. 42:1; ISSN SRENA; ISSN 0038-092X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140100* -- Solar Energy-- Resources & Availability
ASIA
AVAILABILITY
CORRELATIONS
DATA ANALYSIS
DEVELOPING COUNTRIES
DIFFUSE SOLAR RADIATION
INSOLATION
IRAQ
MIDDLE EAST
RADIATIONS
SOLAR FLUX
SOLAR RADIATION
STELLAR RADIATION