Noël Djongyang

Bio: Noël Djongyang is an academic researcher from University of Maroua. The author has contributed to research in topics: Photovoltaic system & Geothermal gradient. The author has an hindex of 12, co-authored 54 publications receiving 960 citations. Previous affiliations of Noël Djongyang include University of Yaoundé I & University of Ngaoundéré.

Thermal comfort: A review paper

Abstract: This paper presents a literature review of thermal comfort. Both rational and adaptive thermal comfort approaches are presented. An overview of the human body thermoregulatory system as well as the mathematical modelling of heat exchanged between human body and its environment in the situations of both awaked and sleeping people is presented.

A review of geophysical methods for geothermal exploration

Abstract: Exploration of geothermal resources is important from the energy point of view. Geophysical methods are among the three main disciplines applied on the surface to explore geothermal resources, including geology and the chemistry of thermal fluids. This paper presents various geophysical methods of exploring geothermal reservoir. Some comparisons, advantages, and disadvantages of each method are discussed. It was found that, the most successful methods are aimed at parameters that are directly influenced by the geothermal activity, such as Geophysical well logs, self-potential, Geoelectrical and thermal methods, and are usually referred as direct methods. Other methods explore the physical parameters of the host rock, including magnetic properties, density and seismic velocity, and are usually referred as indirect or structural methods. It appears that, direct methods give information on parameters that are influenced by the geothermal activity, while the structural methods give information on geological parameters which may reveal structures or geological bodies that are important for the understanding of the geothermal system.

Statistical analysis of wind speed distribution based on six Weibull Methods for wind power evaluation in Garoua, Cameroon

Abstract: Wind data analysis and accurate wind energy potential assessment are critical factors for suitable development of wind power application at a given location. This paper explores wind speed distribution to select the two-parameter Weibull methods that provide accurate and efficient estimation of energy output for Wind Energy Conversion Systems (WECS).The dimensionless shape parameter k and the scale parameter C are determined based on measured hourly mean wind speed data in times-series from 2007 to 2012, collected at the Garoua International Airport, main meteorological station, in Garoua, Cameroon. Six numerical methods, namely Empirical Method (EM), Energy Pattern Factor method (EPF), Graphical Method (GM), Maximum Likelihood Method (MLM), Moment Method (MM) and Modified Maximum Likelihood Method (MMLM) are examined to estimate the Weibull parameters. To analyze the efficiency of the methods and to ascertain how closely the measured data follow the Weibull methods, goodness of fit tests were performed using the chi-square test (χ 2 ), correlation coefficient (R 2 ), root mean square error (RMSE) and Kolmogorov-Smirnov test (KOL). The results revealed that the EPF followed by the MM were the most accurate and efficient methods for determining the value of C and k to approximate wind speed distribution. The statistical tests rejected the GM as an adequate method and revealed as well that the EM, MLM and MMLM ranked respectively third, fourth and fifth. Furthermore, the potential for wind energy development in Garoua is not fitted for generating electricity and a very fruitful result would be achieved if windmills were installed for producing community water supply, livestock watering, and farm irrigation. Resume - L'analyse des donnees du vent et l'estimation du potentiel eolien sont des facteurs determinant pour le developpement des eoliennes. Cet article explore les donnees horaires de vitesse du vent afin de choisir les methodes de Weibull a deux parametres, les plus precises et aptes a evaluer l'energie produite par les eoliennes. Le facteur adimensionnel de forme k et le facteur d'echelle C sont ainsi determines sur la base des donnees mesurees (2007 a 2012), obtenues aupres de la station meteorologique de l'aeroport international de Garoua au Cameroun. Six methodes numeriques, a savoir, la Methode Empirique (EM), la Methode du Facteur d'Energie (EPF), la Methode Graphique (GM), la Methode du Maximum de Vraisemblance (MLM), la Methode de Moment (MM) et la Methode Modifiee du Maximum de Vraisemblance (MMLM) sont ainsi examinees pour calculer les parametres de Weibull. Afin d'analyser l'efficience des dites methodes et d'etablir la methode qui se rapproche davantage des donnees mesurees, les tests de performance du chi-carree (χ²), du coefficient de correlation (R 2 ), de l'erreur moyenne quadratique (RMSE) et de Kolmogorov-Smirnov (KOL) ont ete effectues. Les resultats ont revele que les methodes EPF et MM sont les plus precises et efficientes pour determiner les valeurs de C et k. Les tests statistiques ont egalement reveles que la methode GM n'est pas appropriee et que les methodes EM, MLM et MMLM sont respectivement classees troisieme, quatrieme et cinquieme. De plus, the potentiel

Green building research–current status and future agenda: A review

Abstract: Green building is one of measures been put forward to mitigate significant impacts of the building stock on the environment, society and economy. However, there is lack of a systematic review of this large number of studies that is critical for the future endeavor. The last decades have witnessed rapid growing number of studies on green building. This paper reports a critical review of the existing body of knowledge of researches related to green building. The common research themes and methodology were identified. These common themes are the definition and scope of green building; quantification of benefits of green buildings compared to conventional buildings; and various approaches to achieve green buildings. It is found that the existing studies played predominately focus on the environmental aspect of green building. Other dimensions of sustainability of green building, especially the social sustainability is largely overlooked. Future research opportunities were identified such as effects of climatic conditions on the effectiveness of green building assessment tools, validation of real performance of green buildings, unique demands of specific population, and future proofing.