Renewable Energy Research and ApplicationRenewable Energy Research and Application
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http://rera.shahroodut.ac.ir/
Feed provided by Renewable Energy Research and Application. Click to visit.Development of a Simple Model to Estimate Entropy Generation of Earth
http://rera.shahroodut.ac.ir/article_1620_189.html
Entropy generation can be caused by the energy transfer from a high-temperature recourse to a low-temperature resource; this is defined by the second law of thermodynamics. This phenomenon can occur for the Earth by transferring the solar energy from the sun to the earth. The process of entropy generation of the Earth is an important concept for the life of the earth. This process also has significant effects on the global hydrological cycle, carbon cycle of the Earth’s atmosphere, and global warming. This paper presents an approximate method to estimate the entropy generation of the earth caused by the sun. Application of the heat engine to calculate the entropy generation of the planets has been carried out so far. In this research work, the concept of heat engine is applied to calculate the entropy generation of the earth and the atmosphere surrounding it in a relatively simple model. Based upon this calculation, the rate of entropy generation of the earth and its surrounding atmosphere is . Moreover, by considering this imaginative heat engine, the first and second law efficiencies are equal to 0.11036 % and 0.11546 %, respectively. The results of this research work have also been justified by similar works on this topic.Tue, 30 Jun 2020 19:30:00 +0100An Experimental Study on Producing a Sustainable Diesel-like Fuel from Waste Engine Oil
http://rera.shahroodut.ac.ir/article_1673_189.html
Used engine oil is one of the most environment pollutants that is produced in large quantities. Methods of recycling and reuse of the oil are important for sustainable environment. In this work, a new experimental method is proposed for producing diesel-like fuel from the waste engine oil. The study proposes new physical and chemical treatment methods to produce diesel-like fuel from the used engine oil. The produced oil is chemically analyzed to characterize the produced engine oil fuel for application in a diesel engine, to calculate the power produced, to measure the gaseous emissions and to compare with the standard diesel fuel. The diesel-like fuel properties are investigated including viscosity, flash point, pour point, energy content, and gaseous emissions. The diesel-like fuel proves to emit less gaseous pollutants such as NOx than the diesel fuel. The diesel-like fuel is tested in a diesel engine which provided the efficiency of 22.4%. The proposed experimental approach proves sustainable for producing diesel-like fuel from waste engine oils and protects the environment from the abundant amount of the waste engine oil.Tue, 30 Jun 2020 19:30:00 +0100A New Method for Real Time Economic Dispatch Solution Including Wind Farms
http://rera.shahroodut.ac.ir/article_1674_189.html
Economic dispatch in the presence of wind farms is of high interest in power system operational planning. Due to the uncertainty of wind speed and wind power, a probabilistic model is needed for application in economic dispatch solution. The weibull probability distribution function is a common tool to model wind speed probabilistic behavior, but the main challenge is the nonlinearity of wind power generation with respect to wind speed. This causes complexity in probabilistic economic dispatch, which can lead to numerical and time-consuming solution methods. Therefore, linearization of the wind power curve is in the interest of some methods by simply connecting the first point to end point of power curve by a straight line. In this paper, by developing a conventional objective function for ED solution, two main contributions are made to obtain a suitable method for fast and also good accuracy results in real time purposes. At first, an improved method for linearization of wind power curve with respect to previous works is introduced which increases the performance of modelling with respect to the nonlinear model as the base model. The second contribution is developing an analytical routine for economic dispatch by an acceptable time-consuming calculation suitable for real time purposes. The effectiveness of the new approach has been tested on two test systems. The results show the improvement in relative error in ED cost with respect to real nonlinear curve model which reduces the error about one fifth regard to the conventional linearization model.Tue, 30 Jun 2020 19:30:00 +0100Global Solar Radiation, Sunshine-hour Distribution, and Clearness Index: A Case Study of ...
http://rera.shahroodut.ac.ir/article_1676_189.html
Global solar radiation is the sum total of all radiation reaching the earth surface i.e. it includes: the direct and the diffused solar radiation reaching the earth surface. The instrument used for measuring this very important component arriving from the whole hemisphere is the pyranometer. This is one of the most important parameter for applications, developments and researches related to alternative source of clean and renewable energy. In cases where these data are not available, it is very common to use computational models to estimate the missing data, which are based mainly on the search for relationships between weather variables, such as temperature, humidity, precipitation, cloud cover and sunshine hours, among others. In this research work, the baseline data for mean monthly global solar radiation and sunshine hours for three (3) geopolitical zones of Nigeria (sub-sahara regions of Nigeria) with Sokoto (North-western Nigeria) (12.910N, 5.200E), Maiduguri (North-eastern Nigeria) (11.850N, 13.080E) and Ilorin (North- Central Nigeria) (8.430N, 4.500E) were obtained from the Nigeria Metrological Agency (NIMET), Nigeria which spread from 1996 to 2010. A linear regression correlation model was developed and clearness index estimated for each station in this study. The result shows the Angstrom coefficients and for estimating global solar radiation for zone respectively, using the Angstrom-Prescott model. The average global solar radiation for these stations was estimated, results subjected to statistical tests proven to be good estimates. The study concluded that the Angstrom- Prescott model plays a significant role in predicting and estimating solar energy potentials in these regionsTue, 30 Jun 2020 19:30:00 +0100Thermodynamic and Exergy Analyses of a Novel Solar-Powered CO2 Transcritical Power Cycle with ...
http://rera.shahroodut.ac.ir/article_1683_189.html
In this paper, a novel CO2 transcritical power cycle which is driven by solar energy integrated by a cryogenic LNG recovery unit is investigated. In the proposed cycle, the condenser unit of the CO2 power cycle is replaced by a Stirling engine. Thermodynamic and exergy analyses are carried out to evaluate the performance of the presented system. Furthermore, in order to investigate the impact of utilization of Stirling engines instead of conventional condenser units, the proposed cycle is compared with the typical CO2 power cycle. The results show that employing the Stirling engine decrease the exergy destruction from 17% in the typical cycle to 8.85%. In addition, the total generated power of the novel system is considerably boosted up about 15 kW in off-peak times and more than 20 kW in the peak time. Moreover, integration of the Stirling engine also decreases LNG mass flow rate. Therefore, the required heat exchanger area in the LNG heater is also lowered.Tue, 30 Jun 2020 19:30:00 +0100A Case Study on Effect of Inclination Angle on Performance of Photovoltaic Solar Thermal ...
http://rera.shahroodut.ac.ir/article_1695_189.html
A case study is conducted to evaluate the photovoltaic (PV) performance in a horizontal and in an inclined PV solar thermal collector (PVT) for two different PVT geometries; the series flow and the parallel series flow. It is shown that the series flow gives a better photovoltaic performance at a horizontal PVT surface as compared to the parallel series flow. At mass flow rate of 0.03 kg/s and zero inclination angle (horizontal PVT surface), the PV efficiencies are 14.32 % and 14.25 % for series and parallel series flow, respectively. But for an inclined PVT surface, the parallel series performs better than that of the series flow. At mass flow rate of 0.03 kg/s and inclination angle of 45 °C, the PV efficiencies are 13.76 % and 13.87 % for series and parallel series flow, respectively. It can be concluded that the inclination angle is one of the essential parameters that can be used to evaluate any PVT design and make better comparison between different designs. It is also beneficial for researchers and PVT product designers to know the effectiveness of their collector designs for cooling the PV panel at the early product design stage and to base on the optimum inclination angle of the region.Tue, 30 Jun 2020 19:30:00 +0100