Improvement of the hourly global solar model and solar radiation for air-conditioning design in China

Abstract

Hourly global solar radiation is a significant parameter for building thermal simulation and building cooling design. Most of the solar radiation models focus on the monthly or daily values, but very few studies have been carried out on the hourly values. The Zhang and Huang model was developed for estimating the hourly solar radiation based on the dry-bulb temperature difference, relative humidity and cloud cover. In this study, a new model is proposed for all-sky conditions based on the hourly/daily radiation ratio retrieved from the Zhang and Huang model and the measured daily solar radiation dataset. Compared with the Zhang and Huang model, the proposed model is more accurate (the average of R2, 0.90) and the average of RMSE is improved by 29.54%. The latest hourly solar radiation dataset for 17 locations in China from 2006 to 2016 is subsequently established using the proposed model, which can be used to generate the latest Typical Meteorological Year (TMY). As one of the significant applications to buildings, two kinds of hourly solar radiation datasets (the frequency levels of 95% and 97.5%) for 17 locations are also developed, which are usable for air-conditioning design.