Evaluation of enhancement events of global horizontal irradiance due to clouds at Patras, South-West Greece

Ioannis Vamvakas, Vasileios Salamalikis and Andreas Kazantzidis

Renewable Energy, 2020, vol. 151, issue C, 764-771

Abstract: Cloudiness is the dominant factor that affects the transfer of solar irradiance through the atmosphere. Especially the type of clouds, their high spatial and temporal variability, velocity and position relatively to the Sun, could cause events ranging from total reduction to substantial enhancements of surface solar irradiance. In study, the enhancements of Global Horizontal Irradiance (GHI) at South Greece for 2 years are examined. We use 1–min averages of GHI, sunshine duration and synchronized estimations of cloud coverage and type from a digital imaging system. A radiative transfer model is used to estimate GHI under clear skies. For solar zenith angles lower than 80°, 4% of total GHI measurements are considered as enhancements. It is shown that the effect of thick clouds on the GHI enhancements is significantly higher when compared to the thin ones. We also examine cases that correspond to instantaneous clearness index values higher than 1 (Kt > 1): 228 extreme enhancement events are found including 5 cases with GHI values higher than 1367 W/m2 and a maximum value of 1420 W/m2. These results suggest that such events are common and should be included in the design and simulation of the performance of solar energy systems.

Keywords: Global horizontal irradiance; Clouds; Clearness index; Sunshine duration; Enhancement (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0960148119317616
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:151:y:2020:i:c:p:764-771

DOI: 10.1016/j.renene.2019.11.069

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().