Estimation of Global Solar Radiation Using Clearness Index and Cloud Transmittance Factor at Trans-Himalayan Region in Nepal
- 1 Institute of Engineering, Tribhuvan University, Kathmandu, Nepal
- 2 Institute of Engineering, Tribhuvan University, Kathmandu, Nepal
- 3 Institute of Engineering, Tribhuvan University, Kathmandu, Nepal
- 4 Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
Abstract
This paper presents the global solar radiation (GSR) and cloud transmittance factor (cf) measured at the horizontal surface over a period of one year from 2009 to 2010 using CMP6 Pyranometer and NILUUV Irradiance Meter at Lukla (Latitude 26.69 o N,Longitude 86.73?E and Altitude 2850 m) in the foothills of the Mt Everest (8850 m high). Monthly and seasonal variations of global solar radiation as well as correlation between clearness index and cloud transmittance factor at Lukla are presented. The annual average daily global solar radiation is about 3.83 kWh/sq·m/day which is sufficient to promote solar active and passive energy technology at high mountain terrain where there is no other viable alternative sources of energy. The maximum and minimum global solar radiation of 5.33 and 2.08 kWh/sq·m/day is recorded in April and September 2010 respectively. The seasonal variation of solar energy is about 2.87 kWh/sq·m/day and 4.83 kWh/sq·m/day in summer and spring respectively which is not in line with the general trend. The coefficient of determination (R 2 ) between cloud transmittance factor (cf) and clearness factor (K) is found to be 0.97. This novel result can be utilized to estimate the global solar radiation at the horizontal surface where K and cf are available.
- WECS, Water and Energy Commission Secretariat, “Energy Synopsis Report,” Government of Nepal, 2010.
- M. B. Basnyat, “Rural Electrification through Renewable Energy in Nepal,” World Review of Science, Technology and Sustainable Development, Vol. 1, No. 1, 2004, pp. 74-80. doi:10.1504/WRSTSD.2004.004857
- B. K. Bhattarai, “Factors Affecting Solar Ultraviolet Radiation, Based on Some Case Studies in Norway and Nepal,” Doctoral Theses at NTNU, 2007, pp. 26-27.
- SWERA Final Report, “United Nation Environment Program Global Environment Facility (UNEP/GEF),” Solar and Wind Energy Resource Assessment in Nepal (SWERA), 2006.
- K. N. Poudyal, P. Daponte, D. V. Luca, B. K. Bhattarai and B. Sapkota, “Study of Variation of Global Solar Radiation at Different Altitudes of Himalaya Region—A Case Study in Nepal,” 17th Symposium IMEKO TC 4, 3rd Symposium IMEKO TC 19 and 15th IWADC Workshop, Instrumentation for the ICT Era, Kosice, 2010.
- M. Oki and H. Shiina, “Preliminary Study on an Estimation Method for Annual Solar Irradiance at Various Geographical Altitudes,” Eighth International IBPSA Conference, Eindhoven, 11-14 August 2003, pp. 11-14.
- M. Iqbal, “An Introduction to Solar Radiation,” Academic Press, New York, 1983.
- M. B. Sukhera and M. A. R. Pasha, “Solar Radiation Maps for Pakistan,” Solar and Wind Technology, Vol. 4, No. 2, 1987, pp. 229-238. doi:10.1016/0741-983X(87)90053-1
- J. Serm, “Assessment of Solar Energy Potentials for Cambodia,” 2008.
- K. N. Poudyal, B. K. Bhattarai, B. Kjeldstad and B. K. Sapkota, “Solar Radiation Potential at Four Sites of Nepal,” Journal of the Institute of Engineering, Vol. 8, No. 3, 2011, pp. 189-197.
- U. Kenichi and R. Aryal, “Impact of Tropical Convective Activity on Monthly Temperature Variability during Nonmonsoon Season in the Nepal Himalayas,” Journal of Geophysical Research, Vol. 113, No. 9, 2008.
- Kipp and Zonen, “Instruction Manual,” 2008. http://www.kippzonen.com/?product/1251/CMP+6.aspx
- B. A. K. H?iskar, R. Haugen, T. Danielsen, A. Kylling, K. Edvardsen, A. Dahlback, B. Johnsen, M. Blumthaler and J. Schreder, “Multichannel, Moderate-Bandwidth Filter Instrument for Measurement of the Ozone-Column Amount, Cloud Transmittance, and Ultraviolet Dose Rates,” Applied Optics, Vol. 42, No. 18, 2003, pp. 3472-3479. doi:10.1364/AO.42.003472