performance investigation of offset-parabolic solar cooker for rural application

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Theoretical and Experimental Comparison of Box Solar Cookers with and without Internal Reflector

Box solar cookers are commonly built with internal sheet metal painted black as an absorber. In order to increase the performance, a design which incorporates internal reflection is proposed in this paper. The aim of this paper is to report comparisons made between box solar cookers with and without internal reflector. Theoretical modelling of the two types of cookers has been made by considering the radiation, convection and conduction heat transfer employing the thermal network method. The theoretical analysis made was based on steady state heat transfer analysis of the cookers. Experimental comparisons were also made on two cookers having the same aperture area and made from the same type of materials except the internal absorber. The tests were made as per the American Society of Agricultural Engineers (ASAE) procedure. The result of the theoretical analysis predicts that the performance will be higher in the cooker with internal reflector than the same cooker without reflector. The steady state analysis shows that for the cooker with reflection the temperature of the bottom absorber plate is higher than the cooker without reflector. Similarly, results of dry test and water boiling test show better performance by the cooker with reflector. The standard stagnation temperature and the cooking power were higher in the cooker with reflector as compared to the cooker without reflector. In conclusion, the performance of box solar cookers can be enhanced by making appropriate angle side walls of the absorber and providing internal reflection.status: publishe

Wind Energy Data Analysis and Resource Mapping of Geba Catchment, North Ethiopia

Wind energy potential in Ethiopia is estimated to be enormous due to local peculiar landscape situations. However, the country started to utilize the potential only very recently. One of the reasons for low utilization of wind energy in Ethiopia is the absence of reliable and accurate wind energy resource data. Development of reliable and accurate wind atlas helps to identify candidate sites for wind energy applications and facilitates the planning and implementation of wind energy projects. This paper presents wind energy data analysis and wind atlas of Geba catchment in North Ethiopia. The work reported in this paper is based on wind data collected over a period of one year from measuring masts in six different sites in Tigray, Ethiopia. The data was analyzed using various statistical software to evaluate the wind energy potential of the area. Average wind speed and power density, distribution of the wind prevailing direction, turbulence intensity and wind shear profile of each site were determined. Wind Atlas Analysis and Application Programme (WAsP) was used to generate the wind atlas of the area and to develop the wind speed and power density maps. The data analysis indicates that the average wind speed at 10 m above ground level (a.g.l.) varies from 3.7 m/s to 6.64 m/s. The mean power density at 10 m a.g.l varies from 64 W/m2 to 301 W/m2. The prevailing wind directions are East and South East directions. The wind resource map developed by WAsP at 50 m indicated that the catchment has good wind power potential having mean wind speed and power density of 6.5 m/s and 288 W/m2, respectively.status: publishe

Solar Energy Resource Assessment of the Geba Catchment, Northern Ethiopia

© 2014 Published by Elsevier Ltd. The global shift towards renewable energy is manifested in developing countries such as Ethiopia primarily because of continuous economic growth in the last two decades and secondly due to the vast untapped potential resources. In addition to other factors, the lack of accurate data of the resources has, however, hampered the development of solar energy technologies. The aim of this paper is to investigate the resource estimation by undertaking direct measurements at selected sites in the Northern part of Ethiopia. This paper presents an assessment of the solar energy resource based on the primary data collected between January 2011 and December 2012. The daily and monthly average global solar radiation is analyzed based on the 10 minute interval measurement retrieved from the data loggers. From the analysis it is seen that the measured values give a better accuracy and distribution of the global solar radiation than earlier Fig.s that were based on satellite images and model calculations. Furthermore, these results can be used to determine the solar resource potential of Northern Ethiopia for further energy development.publisher: Elsevier articletitle: Solar Energy Resource Assessment of the Geba Catchment, Northern Ethiopia journaltitle: Energy Procedia articlelink: http://dx.doi.org/10.1016/j.egypro.2014.10.116 content_type: article copyright: Copyright © 2014 The Authors. Published by Elsevier Ltd.status: publishe

Solar Energy Resource Assessment of the Geba Catchment, Northern Ethiopia

AbstractThe global shift towards renewable energy is manifested in developing countries such as Ethiopia primarily because of continuous economic growth in the last two decades and secondly due to the vast untapped potential resources. In addition to other factors, the lack of accurate data of the resources has, however, hampered the development of solar energy technologies. The aim of this paper is to investigate the resource estimation by undertaking direct measurements at selected sites in the Northern part of Ethiopia.This paper presents an assessment of the solar energy resource based on the primary data collected between January 2011 and December 2012. The daily and monthly average global solar radiation is analyzed based on the 10minute interval measurement retrieved from the data loggers.From the analysis it is seen that the measured values give a better accuracy and distribution of the global solar radiation than earlier Fig.s that were based on satellite images and model calculations. Furthermore, these results can be used to determine the solar resource potential of Northern Ethiopia for further energy development