Quoted from:Chen R ,  Lu S ,  Kang E , et al. Estimating daily global radiation using two types of revised models in China[J]. Energy Conversion & Management, 2006, 47(7/8):865-878.

https://www.sci-hub.ren/10.1016/j.enconman.2005.06.015

INTRODUCTION

Using the daily global radiation data and sunshine hours from 1994 to 1998 at 86 stations in China, the Angstrom model and the Bahel model are both validated and revised. The parameter a of Angstrom model is affected by the geological position, especially the latitude and altitude of the used stations, while the parameter b is little affected. The four parameters of the Bahel model are evidently affffected by the longitude, latitude and altitude of the used stations. Using the total daily data in 1994–1998 at 86 stations together in China, 15 equations are calibrated, and all these equations can simulate the daily global radiation with relatively high accuracy. The revised equations that using geological positions and altitude to adjust the parameters of both the Angstrom model and the Bahel model, can give better results than the original models. The terms cos(Φ) and latitude Φ in the revised Angstrom equations have nearly the same effect, while in the revised Bahel equations, the former term can give better results. Using or not using the longitude k in the revised equations of the Angstrom model does not change the simulation results largely, while in the revised equations of the Bahel model, the longitude k has a relatively important effect. Because the parameter b of the Angstrom model is hardly affected by the positions and altitude of the used stations, the revised equations that just use the basic station information data to adjust parameter a can give nearly the same simulation results as the equations that adjust both the parameters a and b. For the revised Bahel equations, the equations in which all the parameters are adjusted by the geological position and altitude of the used stations can give better results.

Most measuring systems at these reference stations now are automatic, and sunshine hours have been observed without question from about the later 1950s. Thus, using sunshine based models to estimate the global radiation in China has an excellent foreground. The number of reference stations at which the global radiation is observed is 98, and in Chen et al., the authors have used daily global radiation data from 1994 to 1998 at 48 reference stations to validate fifive well known global radiation models, They found that the Angstrom model and the Bahel model can give acceptable results. In this paper, the authors fifirstly use the daily global radiation and sunshine hours data from 1994 to 1998 at 86 stations to validate these two models, then to fifind the variation of the model parameters with the geological position and altitude of these stations and, fifinally, to give some universal equations to estimate the daily global radiation in China.

Rensheng et al. suggested the linear equation to estimate global solar radiation as follows:

\( 𝐻/𝐻_0 = 0.176 + 0.563 𝑆/𝑆_0 . \)

Using the longitude k could not improve the simulation results of the revised Angstrom model, however, it does improve the daily global radiation simulation results in China when it is used in the revised Bahel models.