scholarly journals Estimating monthly means of daily totals of direct normal solar radiation and of total solar radiation on a south-facing, 45/sup 0/, tilted surface

1977 ◽  
Author(s):  
E. Boes ◽  
I. Hall
1996 ◽  
Vol 118 (3) ◽  
pp. 183-189 ◽  
Author(s):  
B. E. Psiloglou ◽  
C. A. Balaras ◽  
M. Santamouris ◽  
D. N. Asimakopoulos

The diffuse radiation incident on an inclined surface is composed of both the sky diffuse radiation and the ground-reflected radiation. Depending on the model used to calculate the sky diffuse radiation and the estimated albedo value, it is possible to introduce a significant error in the prediction of the total radiation incident on a tilted surface. Twelve sky diffuse submodels associated with four different albedo submodels are used to estimate the total radiation on the tilted surface from data on the horizontal plane. The predicted total solar radiation values are compared with measured data on a south facing vertical surface, from four representative south and north European locations. Root mean square error, mean bias error, and a t-test are used to determine the intrinsic performance of each combination of diffuse tilt and albedo submodel. Accordingly, the various model combinations do not exhibit a statistically significant difference between measured and calculated values.


2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Orhan Ekren

Characteristics of site-specific solar irradiation is required to optimize a solar energy system. If no tracking system is used, the amount of electricity or heat produced by solar energy depends on the total solar radiation on a tilted surface. Although pyranometer measures direct plus diffuse solar radiation on a horizontal surface, there are many locations where diffuse radiation is not measured. Also, diffuse radiation is necessary to determine the total radiation on a tilted surface. Therefore, in this study, new correlations for diffuse solar radiation is proposed as a function of atmospheric parameters for Urla (Izmir, Turkey). After applying the statistical procedure on the measured data, seven new correlations are proposed for the ratio of hourly average diffuse and total radiation. Also, the ratio of monthly average daily diffuse and total radiation for this region is proposed.


2021 ◽  
Author(s):  
Katarzyna Zielonko-Jung ◽  
Justyna Janiak

AbstractThe present study is aimed at the analysis of possibilities for shading southern frontage of street oriented along the E-W axis by the single row of trees, parallel to the southern elevations. The effectiveness of solar control shading was tested depending on the geometric relationships between trees and buildings. Numerical simulation analyses were conducted in Rhinoceros® program for the street located in humid continental climate in city Płock, Poland (52°32′50 “N 19°42’00 “E), for the day of the highest degree of total solar radiation in the year i.e. June 7th, during hours: 8.00a.m - 5.00 p.m. The analysis has proved that a row of 20–25 year old Sycamore Maple ‘Rotterdam’ in the street 30 m wide and 18 m high (H/W = 0.6), can provide solar protection for the southern frontage, especially when trees are located no more than 4 m away. Location of greenery within the range of 4 to 5 m from the buildings leads to a radical reduction in the possibility of shading the wall surfaces (at 5 m to 0%). Over 90% of the shading area of the ground floor façade walls was found when trees were within the distance 2 and 3 m away from the building.


Solar Energy ◽  
1977 ◽  
Vol 19 (3) ◽  
pp. 307-311 ◽  
Author(s):  
J.A. Sabbagh ◽  
A.A.M. Sayigh ◽  
E.M.A. El-Salam

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