PERFORMANCE COMPARISON OF FIXED, SINGLE, AND DUAL AXIS TRACKING SYSTEMS FOR SMALL PHOTOVOLTAIC SYSTEMS WITH MEASURED DIRECT BEAM FRACTION

摘要

The purpose of this study is to evaluate the side-by-side performance of small photovoltaic systems with fixed, single, and dual-axis tracking capabilities with regard to the presence of direct beam irradiance. Selected geographic regions within the United States will be evaluated for impact to performance utilizing the results of the analysis. Independent variables of the study include tracking system type (fixed, single, and dual axis), as well as measured direct beam fraction irradiance reported as percent of total irradiance. The dependent variable (performance) is power production from each individual photovoltaic system and reported in units of Watts. The hypothesis is that although power production and irradiance are linearly related, power and direct beam fraction are not. This study is phase Ⅱ of an initial study completed at the Appalachian State University Solar Lab during fall 2011 by John W. Robinson and Brian Raichle in which power enhancement from a fixed axis to a single axis tracking system was reported, with a strong direct beam fraction dependency.