فهرست مطالب

Energy & Environment - Volume:9 Issue: 2, Spring 2018

Iranica Journal of Energy & Environment
Volume:9 Issue: 2, Spring 2018

  • تاریخ انتشار: 1397/05/15
  • تعداد عناوین: 10
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  • Djamel Bensahal *, A. Yousfi Pages 78-85
    This paper is focusing on hourly air temperature estimation model (MAT) using available meteorological measured data located in Laghouat (Algeria). The hourly air temperature defined by the present model can be calculated at any time of the night or the day period based on atmospheric pressure, global solar radiation and relative humidity data. This work was compared with three published models from the literature as: Wave, Idliman and Double cosine. Fifteen months of hourly atmospheric pressure, global solar radiation, relative humidity and air temperature data collected during the period (January 2015 to March 2016) were used to test the accuracy of the various models studied. The analysis of the days selected randomly showed that the MAT model gave substantially good fit to the observed data. The RMSE of the MAT model is less than 0.5 oC during all the period of study than the other models studied ranged in the interval (2 oC, 4 oC). The estimated results are compared to the measured ones by using statistical parameters tests such as the mean bias error (MBE), the mean percentage error (MPE), the mean absolute error (MAE), the root mean square error (RMSE) and the coefficient of determination (R2).
    Keywords: Air Temperature, Global Solar Radiation, Atmospheric Pressure, Relative humidity
  • Y. Jani *, K. Pehme, A. Bucinskas, J. Burlakovs, W. Hogland Pages 86-90
    Mining landfills and open dumpsites is associated with (40-70% by mass) fine fraction of particle sizes less than 20 or 10 mm. Soil and trace elements of considerable concentrations typically dominate the composition of this fraction. In the present paper, a modified three steps sequential extraction procedure was used to fractionate Cu, Zn and Cr in the fine fraction of waste sampled from Högbytorp (Sweden) and Torma (Estonia) landfills. The results showed that the major concentrations of Cu (98.8 and 98.6 wt%) and Cr (98.5% and 98.4 wt %) in fines from Högbytorp and Torma landfills, respectively. These data were found associated to the residual fraction. Noticeable concentrations of Cu and Cr were also found associated within the water -soluble fraction, which could be regarded as a potential risk. The Zn displayed different behavior by distributing in all the sequential extraction fractions in the fine fractions from the two landfills. Specifying the metals content using this method is essential to explore the valorization as well as the potential environmental risks by these fines fractions.
    Keywords: Metals speciation, Metals fractionation, Sequential extraction, Metals mobility, Fine fraction
  • A. Sidiki *, W. Li, M. Alhousseini Pages 91-99
    The development of solar photovoltaic faces some difficulties in West African countries; such as: high cost of kW/h produced and long duration of return on investment. To that, there are some installation and operation aspects of Photovoltaic(PV) modules. In terms of installation, the incline plays a predominant role in the efficiency of a field photovoltaic. Indeed, the modules being fixed, it is, therefore, necessary to find the right incline so that they can capture the most solar energy every day. In terms of operation, PV modules need to be exposed to outside in order to operate under the most possibility of direct sunlight. Such equipment is therefore subjected to a natural climatic condition causing a great impact on its performance. This article deals with the influence of the operating parameters (optimal tilt and dust deposits) of PV modules in view of their improvement in West African countries such as Mali. After the choice of the cleaning by cloth and the different inclines of the modules were studied; the experiments were developed during the months of April-May-June, 2017. The results showed a reduction of PV modules from 4 to 14% of their efficiency was due to the accumulation of dirt on their capture surface. In addition, this study reveals an impressive
    Result
    a simple cleaning can save us energy about 140 FCFA/m2/month. Similarly, comparing with the outputs of the PV modules for different inclinations; it emerged that the optimal angle of inclination of the modules is slightly higher than the latitude of the study’ s place (about 15 °).
    Keywords: Photovoltaic modules, Average power, Dust deposition, Surface cleaning, Optimal incline
  • Amir Hasheminezhad * Pages 100-104
    Today, the production of biodiesel from waste cooking oil due to its renewability, low cost of production and also low pollution become more popular. In this research, the factors affecting the production of biodiesel by trans-esterification method from waste cooking oil were evaluated. For this purpose, a batch reactor which equipped with a mechanical stirrer, was designed and constructed. Waste cooking oil as feedstock and methanol is used with 1:6 molar ratio in the presence of potassium hydroxide as a catalyst to 1% by weight of waste cooking oil used. In order to optimize the production process, these three parameters including rate of stirring at 3 levels (450, 550 and 650 rpm), temperature at four levels (40, 50, 60 and 70 °C) and reaction time at 6 levels (10, 20, 30, 40, 50, 60 min) were considered. The results indicated, more than 90% of ester conversion occurred in the first 30 minutes and biodiesel production increased and reached its maximum amount at stirring speed of 650 rpm and also the highest rate of esters conversion occurred at 60 ?. Thus, 60 °C for reaction temperature and 650 rpm for stirring speed at 30 min are optimum production condition in order to reach the most amount of biodiesel from waste cooking oil using a batch stirred tank reactor.
    Keywords: Biofuels, Biodiesel, Trans, esterification, Potassium hydroxide, Methanol
  • Akram Al-Khazzar * Pages 105-113
    In this study, PVsyst simulation software is used to analyze a PV grid tied system in a typical primary school in Iraq. The proposed system is 5kW which is affordable and applicable from the cost and required area points respectively. The monthly averaged electrical load for a typical school is approximately calculated. The system simulation has been done for thirteen Iraqi provinces while it is described and its performance is analyzed in details for Baghdad city as an example. The performance ratio for the system in Baghdad is 0.825 and about 9.82MWhr is generated by the system per year, 62.7% is consumed by the load and the remaining is injected to the national grid. The results showed that the initial capital cost is 5,442$ which is returned after five and a half years. The cost of 1 kWhr if the system operates for 10 years is 0.058$. This study clearly demonstrates that photovoltaic power system can effectively assist the peak load on the grid. In addition, these systems are very economical/no maintenance project and can be hooked to any the peak time load.
    Keywords: Solar energy, Photovoltaic system, Grid, tied systems, Simulation, Iraq, PVsyst
  • Olakunle Salawu *, Akindele Okedoye Pages 114-120
    This study examines the second law of thermodynamic gravity-driven viscous combustible fluid flow of two-step exothermic chemical reaction with heat absorption and convective cooling under bimolecular kinetic. The flow is acted upon by periodic changes in the axial pressure gradient and time along the axis of the channel with the existence of magnetic field. The heat convection at the channel surfaces with the environment is the same and satisfies the Newtons law of cooling. The dimensionless main equations of the flow are solved using a convergent and stable semi-implicit finite difference method. The effect of some fluid parameters associated with the problem on momentum and temperature are obtained. The expression for irreversibility ratio, volumetric entropy generation and Bejan number along with the graphical results are presented and quantitatively discussed.
    Keywords: Heat absorption, Entropy generation, Bimolecular kinetics, Bejan number, Viscous combustible
  • Tasmira J. Malek, S. H. Chaki Chaudhary, J. P. Tailor, M. P. Deshpande Pages 121-129
    The effect of Mn doping on Fe3O4 nanocrystalline spinel particles is studied. Two doping concentrations of 10 and 15% Mn were employed. The nanoparticles synthesis was carried out by wet chemical reduction technique. The energy dispersive analysis of X-ray confirmed the stoichiometry of the samples. The X-ray diffraction technique was used to determine the crystal structure and particles size of the synthesized nanoparticles. The electron microscopy revealed that both the synthesized nanoparticles surfaces have flower-like patterns and the particles are spherical. The optical absorption study showed that the absorption is more in case of 10% Mn doped compared to 15% Mn doped Fe3O4 nanoparticles. The Fourier transform infra-red spectroscopy revealed that both the samples contain characteristics bands. The magnetization variation with temperature with zero field cooled and field cooling conditions for two different applied magnetic fields of 500 Oe and 1000 Oe as well as the hysteresis study was carried out by vibrating sample magnetometer technique. The obtained results are discussed in details.
    Keywords: Fe3O4, Nanoparticles, Wet chemical reduction, Surface morphology, Magnetic properties
  • Mohammad Shaik*, Kolla Srinivas Pages 130-136
    Now a days Fridges and Air-conditioners are mostly used in domestic environment. The CFCs have been almost ruled out since 1995 due to their huge impact on the ozone layer, due to the above problem HFC refrigerants are introduced but these are having a high GWP value, which causes environmental pollution. But later Kyoto protocol came into existence which stated the need to replace HFC’S due to their high GWP values. Along with the prevention of environmental pollution, performance improvement also very important. Performance of a conventional refrigeration system can be improved with the help of liquid-suction heat exchanger. So in this paper, Thermodynamic analysis of domestic refrigerator with liquid suction heat exchanger using R134a as a refrigerant was done and the results are compared with various low gwp refrigerants like, HFC152a, HC290, HC600a, HFO1234yf and HFO1234ze(E) as a possible alternative to 134a without any modification to the system. Performance parameters like COP, Refrigeration Effect, Compressor Work and Pressure ratio have been reported at various operating parameters like evaporator temperature, condenser temperature. Theoretical results revealed that all the low GWP refrigerants used in the analysis have a slightly lower performance the R134a at various condenser and evaporator temperatures
    Keywords: Domestic refrigerator, GWP, R134a, R152a, R1234yf, R1234ze (E), R290, R600a
  • G. Boligan Rojas, R. Lorenzo Avila Rondon *, A. Carolina Melendez Gurrola Pages 137-145
    The aim of the present study is to assess theoretical and practical analysis of scientific publications on solar desalination. This analysis is proposed within mechanical design theory framework. For this, inductive and statistical methods were used in analysis of the scientific publications of different specialties that deal with the design process of solar desalination. With the use of the mentioned methods a tendency was obtained that justifies applying the study results to this type of devices of the approaches of the theory of the mechanical design analyzed. Statistical analysis is conducted for the above assessment not only analytically but quantitatively. This gives responses to problems currently posed by different authors related to the possibility of linking several disciplines used today in isolation for the application of mechanical design theory to this type of solar desalination.
    Keywords: Desalination, Mechanical design, Meta-analysis, Solar energy, Functional modeling, Design representation, Humidification-dehumidification
  • Optimization of Whey Treatment in Rotating Biological Contactor: Application of Taguchi Method
    Atieh Ebrahimi, Ghasem D. Najafpour *, Michael Anazadeh, Mohammad Ghavami Pages 146-152
    Industrial waste management is the main concern of sustainable environment, and the proper control and operation of wastewater treatment plants for efficient removal of pollutants are certainly important. In this study, the L16 orthogonal array of the Taguchi method was applied to determine the optimum condition of some controlling parameters such as organic loading rate, hydraulic retention time, number of stages, rotational speed and recycling for treating whey effluent in a rotating biological contactor (RBC). In order to determine the impacts of levels and factors, the optimum condition of the experiment was predicted and determined. QUALITEK-4 has reported 76.25% COD removal based on a desired experimental condition (COD: 50000 mg L−1, HRT: 24 h, No. of stages: 3). To improve the performance of the RBC, second optimum condition (COD: 50000 mg L−1, HRT: 24 h, recycling: positive, rotational speed: 10 rpm, No. of stages: 3) was also investigated. According to the above-stated conditions, the highest COD removal was found to be 98%. Furthermore, two sets of test experiments were also conducted in lab scale under optimum conditions, and the prediction of other combinations of factors/levels was evaluated. Overall, the experimental results demonstrated that Taguchi method was able to predict COD removal with an average relative error of 6.5%.
    Keywords: COD removal, Controlling parameters, RBC reactor, Taguchi method, Whey effluent