[7]Solar position algorithm for solar radiation applications英文教材.pdf

Solar Energy 76 (2004) 577–589 /locate/solener Solar position algorithm for solar radiation applications Ibrahim Reda *, Afshin Andreas National Renewable Energy Laboratory (NREL), 1617 Cole Blvd., Golden, CO 80401, USA Received 28 July 2003; received in revised form 26 November 2003; accepted 3 December 2003 Communicated by: Associate Editor Pierre Ineichen Abstract There have been many published articles describing solar position algorithms for solar radiation applications. The best uncertainty achieved in most of these articles is greater than ±0.01 in calculating the solar zenith and azimuth angles. For some, the algorithm is valid for a limited number of years varying from 15 years to a hundred years. This report is a step by step procedure for implementing an algorithm to calculate the solar zenith and azimuth angles in the period from the year 2000 to 6000, with uncertainties of ±0.0003. The algorithm is described in a book written by Jean Meeus in 1998. This report is written in a step by step format to simplify the complicated steps described in the book, with a focus on the sun instead of the planets and stars in general. It also introduces some changes to accom- modate for solar radiation applications. The changes include changing the direction of measuring azimuth angles to be measured from north and eastward instead of being measured from south and eastward, and the direction of measuring the observer’s geographical longitude to be measured as positive eastward from Greenwich meridian instead of neg- ative. This report also includes the calculation of incidence angle for a surface that is tilted to any horizontal and vertical angle,