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Abdoli M.A.,University of Tehran | Amiri L.,University of Tehran | Baghvand A.,University of Tehran | Nasiri J.,Renewable Energy Organization of Iran | Madadian E.,McGill University
Environmental Progress and Sustainable Energy | Year: 2014

Anaerobic digestion (AD) treatment of agricultural and animal waste can be considered as a means of enabling environmental remediation. This research investigated two conditions of anaerobic co-digestion of maize waste and cow dung. This was done by placing a mixture of cow dung and maize waste together in a floating drum digester that was run at two different cow dung/maize ratios of 10:1 and 10:5. Batch conditions were on a bench-scale of AD, 5 L in volume, developed to operate under mesophilic (36 ± 1°C). Results showed that biogas and methane yields from mesophilic digestion at the ratio of 10:1 were lower than yields obtained at ratio tested in the second run (10:5). Biogas yields were 250 and 480 L/kg VS for first and second runs, respectively. In the case of methane, these amounts were presented at 130 and 300 L/kg VS. Furthermore, the average methane content of biogas was calculated as 51 and 62%, in first and second runs respectively. The total biogas production of the reactor increased by 92% when substrates were fed in second condition ratio compared to biogas production during the first condition ratio. In continue the effect of adding maize waste on biogas yield from cow dung was evaluated in batch digesters under mesophilic conditions. The addition of maize waste to cow dung presents a viable method to improve biogas yield, as well as a means to use maize waste. Copyright © 2013 American Institute of Chemical Engineers Environ Prog.

Mohammadkarim A.,Islamic Azad University at Tehran | Kasaeian A.,University of Tehran | Kaabinejadian A.,Renewable Energy Organization of Iran
International Journal of Renewable Energy Research | Year: 2014

Outlet temperature of the collector for efficiency of water-in-glass evacuated tube solar domestic hot water system with natural circulation is generally more than the flat plate collector systems. Additionally, this type of evacuated tube solar collectors with the free circulation is economically cheaper than heat pipes collector systems, this system is widely used in the world. This paper is dedicated to simulation of evacuated tube solar water heating system with natural circulation under the climatic conditions in Tehran city with TRNSYS software. Diagram of the components used in the simulation of the TRNSYS has fully been studied including Type71 for evacuated tube collector with horizontal tank above it with natural circulation and five nodes in the vertically tank stratified in order to control the temperatures out of the collector. Vertical tank increases the tank temperature out of the collector for the household uses. After the simulation we obtain the regression linear curve of the efficiency of the evacuated tube solar domestic hot water system against heat loss of this system in spring and summer seasons with the solar irradiation and mean and ambient temperature in each selected day.

Rahmatmand A.,Shiraz University | Yaghoubi M.,Shiraz University | Raesi M.,Shiraz University | Niknia I.,Shiraz University | Kanan P.,Renewable Energy Organization of Iran
Journal of Optoelectronics and Advanced Materials | Year: 2013

Among concentrated solar power (CSP) technologies, parabolic trough technology has been established worldwide due to current advances in technical and economical development of these systems. In this paper, durability and performance of current configuration of Shiraz Solar Power Plant (250 kW) is analyzed using the measurements of important parameters including the oil inlet/outlet temperature of the collector's field, thermal efficiency, direct radiation during 2009-2011 and system major deficiencies regarding installation and operating condition are discussed. In addition, effects of different factors on thermal efficiency of collector's field such as dust deposition and sun tracking are also studied.

Esfahanian V.,University of Tehran | Salavati Pour A.,University of Tehran | Harsini I.,Islamic Azad University at Karaj | Haghani A.,Renewable Energy Organization of Iran | And 3 more authors.
Journal of Wind Engineering and Industrial Aerodynamics | Year: 2013

In this study, a mixed CFD (Computational Fluid Dynamics) and BEM (Blade Element Momentum Method) analysis is implemented for simulating the flow field around a wind turbine rotor to predict the aerodynamic performance such as the Power Curve diagram and the forces and moments imposed on the rotor blades that are essential in structure and/or aeroelastic design. The present approach requires considerable less computational time and memory than three-dimensional simulation of a wind turbine rotor by merely CFD methods, while retains the desirable accuracy. This work consists of two parts: 1-calculating 2D aerodynamic coefficients of several spanwise sections of the blades by CFD methods, using Fluent commercial software. 2-Simulating 3D-flow field through the wind turbine rotor using the BEM technique. To validate the current approach, the Combined Experiment Phase II Horizontal Axis Wind Turbine known as NREL Phase II Rotor is used. The comparison indicates that the combination of CFD and BEM methods is much faster than merely CFD approaches while accurate enough to be used for engineering purposes. © 2013 Elsevier Ltd.

Tizpar A.,Renewable Energy Organization of Iran | Satkin M.,Renewable Energy Organization of Iran | Roshan M.B.,Renewable Energy Organization of Iran | Armoudli Y.,Renewable Energy Organization of Iran
Energy Conversion and Management | Year: 2014

In this paper, wind power potential of Mil-E Nader region is statistically analyzed based on 10 min measured short term wind data. Weibull parameters at 40 m height have been estimated and used to describe the distribution of wind data and its frequencies. Additionally, diurnal and monthly wind speed variations have been calculated. Based on power law model and average wind speed at three heights (10, 30 and 40 m), wind speeds at higher elevations have been extrapolated. Energy analysis has been carried out to find best hub height by comparing energy production of several wind turbines with different classes and hub heights. The energy production analysis showed that the wind turbines with 80 m height have high production in comparison to the others. © 2013 Published by Elsevier Ltd.

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