access deny [1301]
Research field: Development of advanced technologies for production and evaluation of renewable energies
Expert: hadi zare
Phone: 48292200
Address:
access deny [1026]
Today renewable energies such as biodiesel have considerable role in the bio-based economy. Long production time and low efficiency are a number of problems in biodiesel production that is essential to be considered when designing and operating the biodiesel production systems. In this study, using safflower oil in a hydrodynamic cavity reactor, biodiesel fuel was produced in the possible shortest time and maximum efficiency. The effect of reaction time (30, 60 and 90?s), concentration of potassium hydroxide catalyst (0.75%, 1% and 1.25%), alcohol to oil ratio (6, 8 and 10) and rotor-stator distance (1?cm, 2?cm and 3?cm) on the reaction yield were analyzed. The results were analyzed by response surface methodology. Among the independent var
Dielectric barrier discharge (DBD) cold plasma (CP) was used for surface treatment of fennel (Foeniculum vulgare Mill.) seeds and spearmint (Mentha spicata L.) leaves, followed by hydro-distillation, to enhance essential oil (EO) yield extraction. Response Surface Methodology (RSM) was applied to optimize the EOs yields extraction. The experiments were designed using the central composite design (CCD) with two independent variables: X1: exposure times (5-15 min); and X2: applied voltage values (17-23 kV). The EOs yields were enhanced by small defects, generated on the fennel seed coat and spearmint leaf surface. The optimum yield was achieved at 10 min exposure time, and 19 kV applied voltage, by 1.83 (% v/w) and 1.81 (% v/w), consi
Energy crises and environment impact forced governments and countries to develop utilizing renewable energy in different forms. One of the first forms of alternative energy which was in use is bioethanol which is using in SI (spark ignition) engines as pure fuel or after blending with gasoline. The selection of proper blending of bioethanol plays an important role in the production of alternative energy. In this investigation, the use of TOPSIS (Technique for Order Performance by Similarity to Ideal Solution) to select the optimal value of the engine performance and exhaust pollutants which run at various bio-ethanol-gasoline fuel blends, namely E5, E10, E15 and E20. Obtained results indicate that performance parameters (ie torque, power) f
In this study, heat transfer characteristic and fouling of Novel EGR cooler (Semi-spiral) system were investigated. In this study, waste vegetable oil (Waste Cooking Oil) was used as feedstock for biodiesel production. The experiment was conducted in different loads (25%, 50% and 75%) and different speeds (2100rpm and 2400rpm). Four fuel blends were prepared and used (B0, B5, B10, and B15). The new EGR cooler has 6 tubes in length of 19 cm and overall heat transfer coefficient of 35.63 W/m^ 2 K which is acceptable with compared to overall heat transfer coefficient of shell and tube heat exchanger. Also, the total resistance of fouling (Rft) derived was 0.002712 m^ 2 K/W. The maximum heat transfer efficiency is 94% and the minimum heat trans
H-type Darrieus vertical axis wind turbines (VAWT) have omnidirectional movement capability and can get more power compared to other VAWTs at high tip speed ratios (λ). However, its disadvantages are self-starting inability and low generated power at λ less than 1. The performance of H-type Darrieus wind turbine at λ< 1 was studied using double multiple stream tube (DMST) model and two-dimensional computational fluid dynamic (CFD) simulation. In CFD simulation, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations were used and the turbulence model was solved with SST k-ω model. The performance of fifteen various wind turbines was determined at fourteen wind velocities by two solution methods. The effect of chord length, solidi
The performance of a developed brackish water reverse osmosis (BWRO) desalination unit integrated with a stand-alone hybrid photovoltaic-thermal (PVT) module was evaluated under the climatic conditions of Tehran (35.68? N latitude 51.42? E longitude). From the experimental results, the maximum surface temperature of the PV module and thermal efficiency of the PVT module were recorded as 60.38 ?C and 83.7%, respectively at the set-point temperature of 50.00 ?C for the thermostat, and under the average solar radiation of 971.34 W/m2. During the evaluation, the maximum average productivity of the BWRO unit was obtained as 13.98 L/h when temperature values of the PV module, soft water, and brackish feed water (BFW) were recorded as 52.94 ?C, 28
Lubricants are among the largest drivers of global oil demand in the world. The negative environmental impacts resulting from the entry of direct mineral lubricants necessitates the application of bio-lubricants as an excellent alternative to mineral lubricants. The main resources of bio-lubricants are edible/non-edible oils. The use of edible oils as the primary feedstock for bio-lubricant production in developing countries like Iran is being faced with several controversial challenges including the high dependence of the country to edible oils import, the high price of edible oils, the crisis of food shortage, and the negative impact of edible oils on energy security. The application of non-edible oils as a sustainable bio-lubricant resou
In recent years, biodiesel has been demonstrated to offer a suitable level of reliability and attracted the attention of many researchers. Accordingly, various studies have been carried out to account for the biodiesel production and application, producing valuable reports and findings. In this research study, the effects of biodiesel on engine noise were studied on the basis of a time–frequency analysis. To do so, the acquired acoustic signal was initially filtered and denoised. Then the signal was transferred to the time–frequency SPL domain using short-time Fourier transform. In the A weighted signal, the SPL of all treatments were compared using an innovative visual technique. In this novel approach, the values of area percentages o
Biodiesel fuel has some disadvantages including increase in NOx, poor atomization and incomplete combustion. Additives and catalysts can be used to reduce the negative effects of biodiesel fuel. In addition, the use of metal oxide and metal nanoparticles causes environmental hazards. However, using biodegradable nanoparticles can significantly reduce such concerns. The present study investigated the effect of adding GQD?+?E to B10 fuel on the emission and performance characteristics of a diesel engine. B10 was blended with GQD (90?ppm) and bioethanol (E2, E4, E6 and E8% vol). Performance and emission characteristics, including power, torque, SFC, CO, CO2, UHC and NOx emissions were measured at the speeds of 1800, 2100 and 2400?rpm and full
Due to the damaging environmental impacts resulting from direct entry of mineral lubricants into the environment, the use of bio-lubricants as a sustainable and renewable alternative to mineral lubricants is necessary; therefore, bio-based lubricants play an important role in overcoming existing challenges and reducing energy consumption. The present research has been conducted to intensity the production process of TMPTE (trimethylolpropane triester) from rapeseed methyl ester under the influence of ultrasonic irradiation. Ultrasound irradiation is one of the efficient and new methods to intensify the TMPTE production reaction. Ultrasound significantly intensifies the overall process with reduction in energy consumption. The response surfa
There are increasing concerns and growing regulations over contamination and environmental pollution. One of the major concerns is the pollution caused by mineral oils. As the world oil reserves are dwindling the pressures for finding alternative replacements are increasing. Vegetable oils are a biodegradable and renewable source of lubricants. Thus, they seem to be attractive candidates for the replacement of mineral oils. In this study, chemical modification of sunflower waste cooking oil through epoxidation reaction was used to improve its physicochemical properties to be used as biolubricant. Then, using the response surface method (RSM), the reaction yield was statistically modeled as a quadratic regression equation and optimal points
This study first aims to determine the physical characteristics of bioethanol from its dielectric properties during the production process. For this purpose, bioethanol samples were produced from sugarcane molasses under different fermentation conditions such as temperature and reaction time. The main permittivity properties, including dielectric constant and loss factor at various frequencies, were measured as the inputs, whereas flash point and octane number, as significant physical parameters, were considered as output variables. Linear regression (LR) models were developed to predict the relationships between predictors and targets. Next, four learning algorithms – multivariate regression splines (MARS), M5 tree, multilayer perceptron
This study presents the assessments of the acoustic performance of a Herschel-Quincke (HQ) tube, which includes sensitivity analysis and multi-objective optimization of its design variables. A proper model introduced using the flow characteristics of the HQ tube. Input variables were frequency (f), temperature (T), the ratio of areas (R), and tube length (L). These variables were chosen to be varied in a specified range to best characterize the exhaust flow in internal combustion engines. Then a proper multi-objective genetic algorithm (MOGA) was developed for the acoustic performance and geometry optimization of a two-duct HQ tube; the objectives were maximizing the transmission loss (TL) and at the same time minimizing the backpressure (B