Browsing by Author "Djongyang, N."

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A Field Study Of Indicators Of The Performance Of Four Absorption Chillers In The Sudano-sahelian Region Of Cameroon
(University of Eloued جامعة الوادي, 2016-01-01) Chedop, A.n.n.; Djongyang, N.; Tchinda, R.; Zaatri, A.; Kana, J.d.
This paper presents a field study of indicators of the performance of absorption refrigerating systems in the Sudano-Sahelian region of Cameroon. A modeling of various components of the system is performed in order to choose the technology best adapted for the region. Based on the characteristics from the manufacturers, four absorption chillers were studied; namely: EAW Schüco LB 15 and 30; Rotartica Solar 045 and Sonnenklima Suninverse. The model of Kühn and Ziegler and meteorological data of the city of Maroua ((14.33 °E, 10.58 °N) were used to assess the coefficient of the performance (COP) of these machines. Results showed that the Sonnenklima Suninverse technology is best suited for the climatic conditions of the Sudano-Sahelian region with COP values between 1.5 and 3.5.
A New Analytical Modeling Method For Photovoltaic Solar Cells Based On Derivative Power Function
(University of Eloued جامعة الوادي, 2016-05-01) Zieba Falama, R.; Dadjé, A.; Djongyang, N.; Doka, S.y.
This paper presents a simple method of optimizing the photovoltaic (PV) generator based on the one diode electrical model. The method consists in solving a second degree equation representing the derivative of the power function. The maximum current and voltage are determined, and the maximum power is deduced. Two popular types of photovoltaic panels constructed with different materials have been considered for the test: the multi-crystalline silicon (Shell S75), and the mono-crystalline silicon (Shell SP70). For various environmental conditions, a comparative study is done between the simulated results and the product manufacturer data. The obtained results prove the efficiency of the proposed method.
A Novel Technique For Improving The Efficiency Of A Photovoltaic Silicon Solar Cell Based On The Band-trap Impact Ionization Phenomenon
(University of Eloued جامعة الوادي, 2015-09-01) Zieba Falama, R.; Mibaile, J.; Djongyang, N.; Doka, S. Y.
In this paper, we consider a photovoltaic silicon solar cell in which the charge carriers are moved solitary. To evaluate the number of charge carriers in the solar cell, the proposed nonlinear reaction-diffusion equation describing the phenomena of carriers transport in solar cell under the effect of band-trap impact ionization has been solved. The results from this equation are solitary solutions. The maximum efficiency of the proposed model has been evaluated for various photo-generation coefficients. The range of the external applied electric field Eo to be avoided has been carried out. The interest of the obtained results is firstly economical since it could be useful in avoiding strong and undesirable external applied electric field on solar cells. The second interest is that they permit to identify the approximate maximum efficiency value of solar cell band-trap impact ionization.
Performance Analysis Of Methods For Estimating Weibull Parameters For Wind Speed Distribution In The District Of Maroua
(University of Eloued جامعة الوادي, 2014-07-01) Kidmo Kaoga, D.; Danwe, R.; Doka Yamigno, S.; Djongyang, N.
In this study, five numerical Weibulldistribution methods, namely, the maximum likelihood method, the modified maximum likelihood method (MLM), the energy pattern factor method (EPF), the graphical method (GM), and the empirical method (EM) were explored using hourly synoptic data collected from 1985 to 2013 in the district of Maroua in Cameroon. The performance analysis revealed that the MLM was the most accurate model followed by the EPF and the GM. Furthermore, the comparison between the wind speed standard deviation predicted by the proposed models and the measured data showed that the MLM has a smaller relative error of -3.33% on average compared to -11.67% on average for the EPF and -8.86%on averagefor the GM. As a result, the MLM was precisely recommended to estimate the scale and shape parameters for an accurate and efficient wind energy potential evaluation.
A Strategy To Improve The Quality Of The Electric Power Produced By A Wind Turbine Under Variable Speed Using A Proportional Resonant Controller
(University of Eloued جامعة الوادي, 2016-05-01) Menga, F. D.; Djongyang, N.; Raïdandi, D.; Tchinda, R.; Zaatri, A.
The wind power is well adapted nowadays as solution to the production of electricity or for mechanical use. But wind is a very fluctuating source of energy; it generates a non-permanent and variable power to the loads. This paper presents a strategy to improve the quality of the electric power produced by a wind turbine under variable speed. The mathematical modeling of the various elements of the conversion system is performed. Two control strategies are developed to improve the quality of the energy produced by the wind turbine. The first consists to a judicious management of the DC bus and the second to control the inverters with a corrective proportional resonant. The results obtained after implementation and simulation under Matlab/Simulink platform are presented.