Solar energy availability study under distinct topographic and cloudiness conditions.
Observed and computed values of percentage of irradiance at different altitudes in V-shaped valleys are compared. Completely clear (Valley parallel and perpendicular to the solar beam) and overcast conditions are considered, and irradiance expressed as a function of slope angles and surface albedo. Irradiance for clear days decreases with increasing altitudes of the observation point in the valley, and with decreasing slope angles. On cloudy days the opposite happens. Global irradiance on the bottom of cone-chaped valleys, depending on slope angles and surface albedos on clear and overcast days was studied with physical and matematical models. For both clear and overcast conditions the percentage of irradiance increases with decreasing slope angles. The contribution due to multiple reflection between ground and cloud bottom for different cloud densities and ground albedos under overcast conditions was studied. Measured and computed values were compared and a curve relating multiple reflection to surface albedofor overcast conditions was established.
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| Format: | Teses biblioteca |
| Language: | Ingles English |
| Published: |
1978.
1994-12-07
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| Subjects: | Agricultura, Energia Solar, agriculture, solar energy, |
| Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/401807 |
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| Summary: | Observed and computed values of percentage of irradiance at different altitudes in V-shaped valleys are compared. Completely clear (Valley parallel and perpendicular to the solar beam) and overcast conditions are considered, and irradiance expressed as a function of slope angles and surface albedo. Irradiance for clear days decreases with increasing altitudes of the observation point in the valley, and with decreasing slope angles. On cloudy days the opposite happens. Global irradiance on the bottom of cone-chaped valleys, depending on slope angles and surface albedos on clear and overcast days was studied with physical and matematical models. For both clear and overcast conditions the percentage of irradiance increases with decreasing slope angles. The contribution due to multiple reflection between ground and cloud bottom for different cloud densities and ground albedos under overcast conditions was studied. Measured and computed values were compared and a curve relating multiple reflection to surface albedofor overcast conditions was established. |
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