International Journal of Research (IJR) e-ISSN: 2348-6848, p- ISSN: 2348-795X Volume 2, Issue 4, April 2015 Available at http://internationaljournalofresearch.org Available online:http://internationaljournalofresearch.org/ Page | 566 Global solar radiation measurement in AbakalikiEbonyi State Nigeria using locally made pyranometer S.N. Nwankwo and M.N. Nnabuchi Department of Industrial Physics, Ebonyi State University, PMB 053 Abakaliki, Nigeria +2348039513033, nwankwo.s.n@gmail.com Abstract This research work focused on the variability of global solar radiation over the area of Abakaliki,Ebonyi State (6 o 20’N, 8 o 06’E) located in South Eastern part of Nigeria for the rainy and dry seasons. The Pyranometer used for this measurement was locally developed and calibrated against a standard pyranometer, it competed favorably with the standard Einstrain Lungs Sensor. The global solar radiation was measured every five minutes from 08:00hours to 18:00hours during the dry season 2011 and rainy season in 2012. The measurements were carried out near the New Physics Laboratory Complex Ebonyi State University Abakaliki, Nigeria. Maximum Irradiances of 1095.10Wm -2 and 689.48Wm -2 recorded in Abakaliki during dry and rainy seasons respectively occurred between 12:00 – 14:00hours local time, whereas the minimum values of 9.20Wm -2 and 9.86Wm -2 respectively are recorded during the sunrise and sunset. Partly cloudy conditions in Abakaliki cause conspicuous oscillations in global solar radiation. This can be attributed to multiple reflections by nearby cloudy layers.The seasonal difference in the observed global solar radiation is 405.62Wm -2 . Therefore solar energy devices can operate continuously in Abakaliki for up to 10 hours in a solar day from 8:00hours to 18:00hours which was the period covered during this investigation. Key words: Solar Energy, Pyranometer, Measurement, Solar Radiation, Irradiance 1.1 Introduction One of the greatest challenges we have in the present millennium is the development of renewable sources of energy, which can supplement the dwindling fossil fuels. Solar energy which can be used in one form or the other is definitely the most promising among all other renewable energy sources. This is true because, every hour the earth receives more energy from the sun than is consumed by mankind in a year, (Patz et al., 1983). The energy transferred from the Sun in the form of radiant energy to the earth’s surface is called solar radiation. Solar radiation is used in Agriculture for crop drying, electricity generation, house heating, and water purification among others (UNIDO, 2003). It is this energy that allows life to flourish. The beauty of solar energy is that it is free, abundant, inexhaustible and non-pollutant. Solar energy warms our planet and gives us our everyday wind and weather. Without the sun’s radiant energy, the earth will gradually cool and become encased in a layer of ice. Measurement of solar radiation per unit of surface (Wm -2 ) is called irradiance. Pyranometer is an instrument used for measuring solar radiation on a horizontal surface. Pyranometers are widely used in meteorology, climatology, agriculture, solar energy studies among others, (Rai, 2006). The tropical Nigeria has made solar energy availability unequal and the average is 3.7 KWhm -2 day -1 along the coastal areas to about 7.0KWhm -2 day -1 along the semi-arid areas of the North. The Country however, on the average receives solar radiation level of about