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Title: Computer program for calculating direct and diffuse solar radiation on inclined surfaces in Egypt

Conference · · Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States)
OSTI ID:6669637

A new model is presented for computing both direct and diffuse components of insolation on inclined surfaces in Egypt for a year round. The recent model has the advantage of its independence on expensive or sensitive instruments. The input data comprises the ambient temperature, the atmospheric relative humidity, wind speed and the dust concentration in the atmosphere. In order to have a limited-length program, two days of each month, namely its beginning and middle, were adopted for running the excutation. A polynomial that fits the curve of saturated vapor pressure versus temperature was found. Others were fitted to the curves of both the vertical and horizontal components of the diffuse radiation versus the altitude of the sun. The effect of atmospheric attenuation is taken into account by introducing the transmissivity of the atmosphere. All transmissivity values were calculated for a fictitous monocromatic radiation. Recorded data of the ambient temperature, atmospheric relative humidity, wind speed and dust concentration in the atmosphere for the year 1980 in El-Minia, were introduced to the computer. The output, representing the total insolation on a sloped surface was compared with the experimentally measured values during the same period. A deviation of up to 14.6% was noticed.

OSTI ID:
6669637
Report Number(s):
CONF-820629-Vol.5-Pt.2
Journal Information:
Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States), Vol. 5; Conference: American section of the International Solar Energy Society conference, Houston, TX, USA, 1 Jun 1982
Country of Publication:
United States
Language:
English