Study of clear sky models for Indian climate
Student name: Ms Chris Alice Abraham
Guide: Dr Jami Hossain
Year of completion: 2018
Host Organisation: Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ)
Supervisor (Host Organisation): Dr Indradip Mitra
Abstract: A sound knowledge of solar radiation is quite important in the planning of solar power plant. This thesis is being carried out to study the clear sky models for Indian climate and to find the suitability for each site. Determination of Indian specific clear sky model is inevitable for solar resource assessment studies which is instrumental in energy planning. Solar radiation passing through the atmosphere is absorbed, scattered, reflected back to space or transmitted to the surface of the earth depending upon the composition of the atmosphere. In order to determine the radiation received at the surface, it is important to know the composition of the atmosphere and the optical properties associated with it. Knowledge of the components responsible for the attenuation process becomes essential for the estimation of the correct clear sky model for a particular site. These components mainly include the amount of water vapor, uniformly mixed gases and aerosol particles. These particles are known to be present even during cloudless conditions. Besides, these particles are highly variable in nature, which is why the estimation of solar radiation involves the quantification of each of these parameters. Many physical and empirical clear sky models have been developed using a number of inputs. This study is carried out under cloudless conditions. The solar radiation received on the surface of the Earth is vital in many applications. The solar irradiance incident at a certain location mainly depends on its extra-terrestrial radiation, solar geometry and extinction processes in the atmosphere. Clear sky models help in finding out the terrestrial radiation received after all the attenuation processes it undergoes. The availability of highly accurate ground measurements across various Indian sites is pivotal in determination of the model, specific to each site. The report provides an overview of 3 models, used to compute GHI for a few sites and the results were generated in MATLAB.
