The International Journal of Engineering and Science (IJES) || Volume || 9 || Issue || 02 || Series I || Pages || PP 20-24| 2020 || ISSN (e): 2319-1813 ISSN (p): 20-24-1805 DOI:10.9790/1813-0902012024 www.theijes.com Page 20 Predicting The Global Solar Radiation In Ikwo Using Insolation- Sunshine Correlation P. E. Okpani Department of Electrical and Electronics Engineering, Alex Ekwueme Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria. ----------------------------------------------------------ABSTRACT------------------------------------------------------------- Knowledge of the global solar radiation received at a particular location on the earth’s surface is of utmost importance in order to design and evaluate the performance of any device using solar energy at that location. In this paper the data from the measurements and recordings of the number of sunshine hours in a day undertaken by the Nigerian Meteorological Agency (South East Zone) were analyzed using pertinent equations to predict the monthly mean daily global solar radiation in Ikwo, Nigeria (Latitude 6.18⁰ N, Longitude 8.13⁰ E). The results show that the monthly mean daily sunshine hours range from a minimum of 2.73 hours to a maximum of 7.85 hours while the predicted monthly mean daily global solar radiation on a horizontal surface range from a minimum of 14.30MJm -2 day -1 to a maximum of 22.57MJm -2 day -1 . KEYWORDS: monthly mean daily sunshine hours, monthly mean daily global solar radiation --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 4-02-2020 Date of Acceptance: 20-02-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION The importance of electricity for economic growth and national development cannot be overemphasized. The main sources of fuel for electricity generation as of now are nonrenewable. The use of these conventional fuels leads to environmental degradation. It is therefore pertinent to foster renewable energy sources to make the environment eco-friendly [1]. Solar radiation can provide the much needed renewable energy to energy-deficient third world countries like Nigeria which has abundant untapped solar influx [2] Solar radiation received at a particular location on the earth’s surface depends on two main factors namely the extraterrestrial solar irradiance and the state of the atmosphere. The extraterrestrial solar irradiance is the rate at which solar energy arrives on a horizontal surface at the top of the atmosphere. It varies according to the latitude of the location, the distance of the Earth form the Sun and the time of the year. On any particular day, it varies from zero at sunrise to a maximum at noon and back to zero at sunset [3]. When solar radiation enters the atmosphere a part of the incident energy is removed through the processes of scattering, absorption and reflection. The scattering of solar radiation is mainly by atmospheric molecules and aerosols. The absorption of solar radiation is mainly by ozone (O3), water vapour (H2O), oxygen (O2), carbon (IV) oxide (CO2) as well as clouds. Fig 1: Fate of solar radiation in the atmosphere Limits of Earth’s atmosphere Extraterrestrial irradiance 16% absorbed by ozone, water vapour, oxygen and carbon (iv) oxide 26% reflected or absorbed by clouds 7% scattered by atmospheric molecules and aerosols. Direct radiation Diffuse radiations Horizontal surface Earths surface