Renewable Energy Resources and Technologies
Ali Ebadi; Ali Akbar Abdoos; Mohammad Ebrahim Moazzen; Sayyed Asghar Gholamian
Abstract
Nowadays, the Permanent Magnet (PM) generator has become an instrumental tool for wind power generation due to its high performance. In this study, an optimal design is established to provide a cost-effective multiphase outer-rotor PM wind generator (OR-PMWG). The cost of the generation system (generator ...
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Nowadays, the Permanent Magnet (PM) generator has become an instrumental tool for wind power generation due to its high performance. In this study, an optimal design is established to provide a cost-effective multiphase outer-rotor PM wind generator (OR-PMWG). The cost of the generation system (generator and power converter) as well as the annual energy output must be optimized to ensure cost-effective PM wind generation. In fact, the main novelty of this paper lies in the presentation of an accurate model of OR-PMWG and the investigation of the design variables affecting annual energy output and the generation system cost (GSC). In this respect, a multi-objective framework is presented to make satisfactory agreement among all objectives. At first, the main optimal design objectives namely generation system cost and annual energy output are optimized separately and then, a multi-objective optimization is established, in which all the objectives are considered simultaneously. In order to tackle these optimization problems, Genetic Algorithm (GA) is adopted herein to determine the design variables. It is also shown that simultaneous optimization with 71.39 (MWh) AEO and 2651.51 (US$) GSC leads to a more optimal design for a PM wind generation system. In addition, the effectiveness of the presented optimal design is demonstrated by making a comparison between a prototype outer-rotor PM wind generator and the theoretical counterpart. Finally, a finite element analysis (FEA) is carried out for the validation of the outcomes obtained from the proposed optimal design.
Renewable Energy Resources and Technologies
Babak Keyvani; Bahador Fani; Hamed Karimi; Majid Moazzami; Ghazanfar Shahgholian
Abstract
Conventional droop control method has been widely adopted for power sharing between Distributed Generators (DGs) in microgrids. However, the mismatched feeder impedance of the Voltage-Sourced Inverters (VSI) may generate reactive power sharing error during islanding operation of a microgrid. In this ...
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Conventional droop control method has been widely adopted for power sharing between Distributed Generators (DGs) in microgrids. However, the mismatched feeder impedance of the Voltage-Sourced Inverters (VSI) may generate reactive power sharing error during islanding operation of a microgrid. In this paper, an improved droop control method is suggested to improve the reactive power sharing accuracy. In the proposed method, the slope correction of the droop characteristics is performed in such a way that the reactive power sharing error is reduced. In this method, the errors of reactive power sharing are detected by applying a clear signal to the microgrids and, then, by adding a new term to the P-ω and correcting the slope of Q-E, the reactive power sharing is done. In this way, the proposed method can successfully improve the reactive power sharing accuracy even at different X/R ratios. Another feature of this method is its high operation speed compared to the other methods of droop feature correction. The simulation results for a prototype microgrid point to the efficiency and flexibility of the proposed method.
Renewable Energy Resources and Technologies
Rahul Dogra; Sanjay Kumar; Nikita Gupta
Abstract
The use of these conventional resources causes continuous depletion of fossil fuels and increased greenhouse effect. Solar power is the major renewable resource used for power generation across the globe. Solar energy activities depend on the available potential of any geographical location. Therefore, ...
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The use of these conventional resources causes continuous depletion of fossil fuels and increased greenhouse effect. Solar power is the major renewable resource used for power generation across the globe. Solar energy activities depend on the available potential of any geographical location. Therefore, prior to the installation of solar technologies for these activities, estimation of solar potential is very important due to costly technologies. Data of solar potential is not present at every location in Himachal Pradesh (H. P.) due to the high cost of measurement instruments. The objective of this study includes the solar potential estimation for 12 cities of the H. P. The present study could be divided into two parts. Initially, Artificial Neural Networks (ANNs) are utilized to estimate global sun radiation utilizing meteorological and geographical data from 23 places. The ANN model with seven input parameters including latitude, longitude, altitude, air temperature, humidity, pressure, and wind speed were used to estimate the solar irradiation. Statistical indicators including Mean Absolute Percentage Error (MAPE) were used for the performance evaluation of these ANNs. The minimum MAPE value was obtained to be 2.39 % with Multi-Layer Perception (MLP) architecture 7-11-1. For the 12 districts of the H. P., the acquired network 7-11-1 was utilized to estimate Global Solar Radiation (GSR). The output of ANN model was implemented in Geographic Information System (GIS) environment to obtain the solar potential map for each month. The available map of the present study may be helpful for solar application in each district.
Renewable Energy Resources and Technologies
Mirmahdi Seyedrahimi-Niaraq; Tohid Nouri
Abstract
Geothermal energy is a non-carbon renewable source from the earth's internal energy. This energy is considered reliable today and has a high potential to reduce the threat of climate change. The main factor that any investor wants to invest in any natural energy source is the resulting economy. In the ...
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Geothermal energy is a non-carbon renewable source from the earth's internal energy. This energy is considered reliable today and has a high potential to reduce the threat of climate change. The main factor that any investor wants to invest in any natural energy source is the resulting economy. In the case of geothermal energy, factors that increase the risk of investing in this sector include higher investment costs, longer payback times than other renewable power plants, and the uncertainty of the size and quality of the resources before the completion of the well drilling operation. The average payback time in geothermal energy systems is 5.7 years, longer than wind and solar energy. According to these factors, the risk of investing in geothermal technology increases. On the other hand, due to its independence from oil and gas, it increases a country's energy security, helps to create direct, indirect, and induced employment, and affects other economic sectors. Also, unlike renewable wind and solar energies, it is not dependent on climate change; therefore, it has higher reliability than other renewable energies. Also, by combining this energy with other renewable energies, its performance can be optimized. For example, in an optimal geothermal-solar hybrid power plant, solar energy provides 48 % of the total energy. In this case, the Levelized Cost of Energy (LCOE) is reduced from 225 $ per MWh (only with geothermal source) to 165 $ per MWh. In this study, while studying the economic effects of geothermal systems, an attempt has been made to address the challenges in this field and present the policies implemented in some countries. It is implied that by providing incentive policies and an appropriate roadmap, it is possible to help attract investment in the operation of geothermal systems.
Renewable Energy Resources and Technologies
Mehran Gheyrati; Asadollah Akram; Hassan Ghasemi-Mobtaker
Abstract
The orientation of greenhouses is one of the effective factors in terms of radiation they receive. In the present study, a multi-span greenhouse (40 m × 93.5 m with a coverage area of 5457.44 m2) located in the central region of Iran was investigated in three orientations including: North-South ...
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The orientation of greenhouses is one of the effective factors in terms of radiation they receive. In the present study, a multi-span greenhouse (40 m × 93.5 m with a coverage area of 5457.44 m2) located in the central region of Iran was investigated in three orientations including: North-South (N-S), East-West (E-W), and Northeast-Southwest (NE-SW: the most frequent orientation of the existing greenhouses in the study area). The solar irradiation received on the outside surface of the greenhouse cover and the amount of irradiation captured inside the greenhouse for each orientation during the cold season were calculated using mathematical modeling and the results were compared. According to the results, in the E-W orientation, the main sections of receiving solar irradiation, such as the south and north roofs, have a better angle toward the sun; therefore, the quantity of solar irradiation captured inside the greenhouse with the E-W orientation was on average 361.48 MJ day-1 more than that with the N-S orientation. The north wall of the greenhouse could not receive the beam radiation for all the orientations investigated, and the total irradiation captured by this section was composed of the diffused radiation and the ground-reflected radiation, which is an important result for insulation of some surfaces of greenhouses.
Renewable Energy Resources and Technologies
Mohammad Hosseinpour; Hassan Ali Ozgoli; Seyed Alireza Haji Seyed Mirza Hosseini; Amir Hooman Hemmasi; Ramin Mehdipour
Abstract
In this study, the partial alteration of fuel consumption of combined cycle power plants was investigated and analyzed using an innovative model. This system is applicable using the fuel derived from the biomass gasification process. For this purpose, energy modeling of an advanced gasification system ...
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In this study, the partial alteration of fuel consumption of combined cycle power plants was investigated and analyzed using an innovative model. This system is applicable using the fuel derived from the biomass gasification process. For this purpose, energy modeling of an advanced gasification system to supply a share of the gas fuel was fulfilled. The results demonstrated that by considering the reasonable capacities for the design, up to 10 % of natural gas fuel could be replaced with syngas. In addition, heat recovery of the plant stack in the Kalina low-temperature cycle enhanced the total efficiency by up to 1.7 %. Therefore, the competitive advantage of the proposed cycle was enhanced compared to conventional power generation systems. A parametric study of the components affecting the integrated cycle performance including alternative biomass fuels, moisture content of biomass fuel, steam-to-biomass ratio, and equivalence ratio of the gasifier was performed, and the permissible values of each factor were obtained. Thus, by utilizing the proposed approach, it is possible to gradually substitute the consumed fossil fuels of power plants with renewable resources to achieve the objectives of sustainable energy development.
Renewable Energy Resources and Technologies
Ehsan Hosseini; Neda Behzadfar; Mahnaz Hashemi; Majid Moazzami; Majid Dehghani
Abstract
Wind turbines can be controlled by controlling the generator speed and adjusting the blade angle and the total rotation of a turbine. Wind energy is one of the main types of renewable energy and is geographically extensive, scattered and decentralized and is almost always available. Pitch angle control ...
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Wind turbines can be controlled by controlling the generator speed and adjusting the blade angle and the total rotation of a turbine. Wind energy is one of the main types of renewable energy and is geographically extensive, scattered and decentralized and is almost always available. Pitch angle control in wind turbines with Doubly Fed Induction Generator (DFIG) has a direct impact on the dynamic performance and oscillations of the power system. Due to continuous changes in wind speed, wind turbines have a multivariate nonlinear system. The purpose of this study is to design a pitch angle controller based on fuzzy logic. According to the proposed method, nonlinear system parameters are automatically adjusted and power and speed fluctuations are reduced. The wind density is observed by the fuzzy controller and the blade angle is adjusted to obtain appropriate power for the system. Therefore, the pressure on the shaft and the dynamics of the turbine are reduced and the output is improved, especially in windy areas. Finally, the studied system is simulated using Simulink in MATLAB and the output improvement with the fuzzy controller is shown in the simulation results compared to the PI controller. Fuzzy control with the lowest cost is used to control the blade angle in a wind turbine. Also, in this method, the angle is adjusted automatically and it adapts to the system in such a way that the input power to the turbine is limited. Compared to the PI controller, by calculating different parameters, the power quality for fuzzy controller is enhanced from 2.941 % to 4.762 % for wind with an average speed of 12 meters per second.
Renewable Energy Resources and Technologies
Alireza Maheri; I Kade Wiratama; Terence Macquart
Abstract
The effectiveness of trailing-edge flaps and microtabs in damping 1P-3P loads has been proven through a series of research work during the past decade. This paper presents the results of an investigation into the effectiveness of these devices in power enhancement and power control for responding to ...
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The effectiveness of trailing-edge flaps and microtabs in damping 1P-3P loads has been proven through a series of research work during the past decade. This paper presents the results of an investigation into the effectiveness of these devices in power enhancement and power control for responding to the issue of where these devices can be used with dual function of load and power control on a medium size turbine. The 300 kW-AWT27 wind turbine is used as the base wind turbine and the effects of adding trailing-edge flaps and string of microtabs of different lengths positioned at different span locations on the aerodynamic performance of the rotor are studied. In each case, the wind turbine simulator WTSim is used to obtain the aerodynamic performance measures. In the next step, the original blade twist is redesigned to ensure that the blade is optimized upon the addition of these active flow controllers. It is found that blades equipped with flaps can increase the annual average power and reduce the blade loading at the same time for constant speed and variable speed generators. Power enhancement is more visible on constant speed rotors, while load reduction is more significant on variable speed rotors. To achieve constant speed rotors, an average power enhancement of around 12 % is achieved for a flap of size 25 % of the blade span located at about 72 % of the blade span. Microtabs are less effective in power control and can improve the produced power only by a few percentage points.
Renewable Energy Resources and Technologies
Hadi Farzan
Abstract
Recently, novel techniques have been developed in building industries to use solar heating and cooling systems. The current study develops a Solar-powered Heating and Cooling (SHC) system for an office building in Kerman and assesses the transient dynamics of this system and office indoor temperature. ...
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Recently, novel techniques have been developed in building industries to use solar heating and cooling systems. The current study develops a Solar-powered Heating and Cooling (SHC) system for an office building in Kerman and assesses the transient dynamics of this system and office indoor temperature. To this end, TRNSYS simulation software is utilized to simulate system dynamics. The developed system comprises Evacuated-Tube solar Collectors (ETCs), heat storage tank, heat exchanger, circulating pumps, axillary furnace, cooling tower, single-effect absorption chiller, and air handling unit. The office indoor temperature is assessed in two scenarios, including commonly-insulated and well-insulated envelopes, while window awnings are used to prevent the sun from shining directly through the windows. The results illustrate that the SHC system can meet the thermal loads and provide thermal comfort in line with ASHRAE standards. The indoor temperature reaches 21 °C and 24 °C on cold winter and hot summer days by using the SHC system; however, without the SHC system, the indoor temperature experiences 15 °C and 34 °C on cold and hot days, respectively. The SHC system provides 45 °C and 15 °C supply air on cold and hot days to keep the indoor temperature in the desired range. A thermostat monitors the indoor temperature and saves energy by turning off the system when no heating or cooling is required. Furthermore, the ETCs can run the SHC system for a long time during daytime hours, but the axillary heater is still essential to work at the beginning of the morning.
Renewable Energy Resources and Technologies
Bharosh Kumar Yadav; Amit Chandra Jyoti; Pintu Kr. Rajak; Ramesh Kr. Mahato; Deelip Kr. Chaudhary; Mehdi Jahangiri; Ram Dayal Yadav
Abstract
The Gravitational Water Vortex Power Plant (GWVPP) is a power generation system designed for ultralow head and low flow water streams. Energy supply to rural areas using off-grid models is simple in design and structure and sustainable to promote electricity access through renewable energy sources in ...
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The Gravitational Water Vortex Power Plant (GWVPP) is a power generation system designed for ultralow head and low flow water streams. Energy supply to rural areas using off-grid models is simple in design and structure and sustainable to promote electricity access through renewable energy sources in the villages of Nepal. The objective of this study is to determine the most favorable gap between the booster and main runners of a Gravitational Water Vortex Turbine (GWVT) to ensure maximum power output of the GWVPP. CFD analysis was used to evaluate the 30 mm gap between the main and booster runners, which was the most favorable gap for enhancing the plant’s power. In this study, the optimum power and economic analysis of the entire plant was conducted in the case of mass flow rates of 4 kg/s, 6 kg/s, and 8 kg/s. The system was modeled in SolidWorks V2016 and its Computational Fluid Dynamic (CFD) analysis was performed utilizing ANSYS R2 2020 with varying multiple gaps between the main and booster runners to determine the most favorable gap of the plant’s runner. This research concluded that optimum power could be achieved if the distance of the main runner’s bottom position be fixed at 16.72 %, i.e., the distance between the top position of the conical basin and the top position of the booster runner. At a mass flow rate of 8 kg/s, the plant generated maximum electric energy (3,998,719.6 kWh) comparatively and economically contributed 268,870.10 USD on an annual basis.
Renewable Energy Resources and Technologies
Sepideh Rahmati Dehkordi; Mehdi Jahangiri
Abstract
In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it ...
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In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it is necessary for architects to have an accurate assessment of the amount of electricity produced in different conditions. Therefore, in the present work, using HOMER software, the energy-econo-Enviro (3E) potential of a Building Integrated Photovoltaic (BIPV) in Abadan was studied. The effect of slope and azimuth of solar cells as well as cloudiness and system losses were investigated using sensitivity analysis. The results showed that the PV-grid system was the most economical option and after the azimuth angle of zero degree, the positive azimuth angle was the most economical. The results also showed that the slope of 30 degree and the angle of azimuth equal to zero was appropriate, for which the price per kWh of generated electricity was calculated to be $0.09. For the use of solar cells in the vertical wall of the building, the southwest direction was the most suitable and based on the results, it was suggested that the western wall of the building should be in the form of “inclined PVs with windows”. The authors of this paper hope that the results of the present work can be used by architects and energy decision-makers as a guide in developing the BIPV use in Iran.
Renewable Energy Resources and Technologies
Marziyeh Gharibian; Bahram Hosseinzadeh Samani; Alireza Shirneshan; Sajad Rostami
Abstract
To investigate the possibility of using fuel for plant origin in a diesel generator, safflower methyl ester was prepared and used as a biodiesel. In this research, biodiesel was produced through a transesterification reaction using a hydrodynamic reactor, which increased the reaction efficiency and reduced ...
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To investigate the possibility of using fuel for plant origin in a diesel generator, safflower methyl ester was prepared and used as a biodiesel. In this research, biodiesel was produced through a transesterification reaction using a hydrodynamic reactor, which increased the reaction efficiency and reduced fuel production time. Upon increasing the reaction time from 30 seconds to 60 seconds, the reaction performance increased by 5.5 %. Then, its important features complied with ASTM D-6751 standard. The performance and pollution indices of the diesel generator engine were tested with compounds B0, B20, B50, B80 and B100. The results of short-term engine tests showed that by increasing the share of biodiesel to 20 %, CO emissions were reduced by 21 % compared to pure diesel fuel, but the amount of NOX increased by 0.82 % compared to diesel. Also, the use of 20 % volume of biodiesel in the fuel composition increased the thermal efficiency of braking, braking power, and braking torque of fuel, compared to diesel. Also, the specific fuel consumption of B20 was reduced by 2 %, which is very important economically. Finally, the TOPSIS analysis illustrated that B50 fuel outperformed pure diesel fuel and other listed fuel combinations.
Renewable Energy Resources and Technologies
Mohamed A. Barakat; Tamer Mohamed Ismail; Sayed Ibrahim Abdel-Mageed; Khaled Ramzy
Abstract
The greenhouse problem has a significant effect on our communities, health, and climate. So, the capturing techniques for CO2 remain the focus of attention these days. In this work, a Chemical Looping Combustor (CLC) was designed and fabricated with the major geometric sizes at the Faculty of Engineering, ...
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The greenhouse problem has a significant effect on our communities, health, and climate. So, the capturing techniques for CO2 remain the focus of attention these days. In this work, a Chemical Looping Combustor (CLC) was designed and fabricated with the major geometric sizes at the Faculty of Engineering, Suez Canal University. The system involves two interconnected fluidized beds. Nickel powder with 150 µm diameter as well as brown coal and liquefied petroleum gas were used as oxygen carrier, solid fuel, and gaseous fuel, respectively. The temperature distributions along the fuel reactor for LPG flow rates of 11 and 18 LPM with and without using nickel powder as well as using preheated reactor were discussed and evaluated. The effects of brown coal diameter change with and without using nickel powder were studied. The CO and CO2 concentrations at combustion gases with and without using nickel powder were conducted for LPG and brown coal fuels. A mathematical model was used to simulate the combustion in CLC using combustion and energy code. The obtained results showed that using nickel powder improved the combustion process and in case of using LPG, the flame color changed to blue which is the color of the complete combustion flame. The CO was reduced by 48.4 % and CO2 was augmented by 66.5 %. In case of using brown coal as solid fuel, CO was reduced by 53.7 % and CO2 was increased by 71.9 %. Finally, there is good agreement between the experimental and numerical results based on the determination coefficient.
Renewable Energy Resources and Technologies
Toyese Oyegoke; Emo Obadiah; Francis Adah; John E. Oguche; Geoffrey T. Timothy; Ismail A. Mantu; Abubakar D. Ado
Abstract
In recent times, limitations and adverse effects of fossil fuels have significantly attracted researchers' attention to green fuels worldwide, especially in developed nations. As a way of assessing this actualization of biorefineries establishment in developing nations, this report surveys the works ...
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In recent times, limitations and adverse effects of fossil fuels have significantly attracted researchers' attention to green fuels worldwide, especially in developed nations. As a way of assessing this actualization of biorefineries establishment in developing nations, this report surveys the works done by various researches towards this great course in terms of promoting and gaining the attention of both government and private investors about the technical and economic feasibility of embracing the use of biofuels, a case of bioethanol in Nigeria. Different classes of feedstocks were reviewed for the laboratory-scale, process scale-up, pilot plant, and techno-economic studies regarding ascertaining the technical and economic feasibility of local setup of a functional biorefinery in Nigeria, which would be beneficial environmentally and economically. The literature survey unveiled that the Bioethanol yield obtained from sugarcane-juice (72.7 %), banana-stems (84.0 %), and cassava (92.0 %) were found to be of highest potential amongst other sugar-based, lignocellulosic, and starch-based feedstock, respectively. The survey further unveils that the volume of process scale-up and economic feasibility studies does not correlate well with the laboratory-scale studies. The bulk of the research works on bioethanol has given preferential attention to laboratory studies. Only a few studies have looked into the commercialization (i.e., scale-up) of the laboratory findings and the economic implications. Presently, only sugarcane and a few cassavas are reported in the literature so far. It is, therefore, necessary for further studies to give attention to the investigation of the commercializing locally developed technologies and the exploration of their economic benefits.
Renewable Energy Resources and Technologies
Aloys Martial Ekoe A. Akata
Abstract
Photovoltaic energy has the potential to become one of the major energy sources used in the households in the tropical region of Africa, where the solar radiation intensity is abundant and almost constant over the year. Solar photovoltaic systems present many advantages when they are integrated in the ...
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Photovoltaic energy has the potential to become one of the major energy sources used in the households in the tropical region of Africa, where the solar radiation intensity is abundant and almost constant over the year. Solar photovoltaic systems present many advantages when they are integrated in the building structure envelope and have a significant influence on the indoor air temperature of dwelling buildings due to the thermal resistance modification. In this paper, a simplified model of the photovoltaic system integrated on the roof of a residential building according to the building construction customs and materials has been designed and modeled. The heat transfer is studied in several situations: with and without a Building Integrated Photovoltaic (BIPV) system and for a building with and without false ceiling. The BIPV system installed over an effective area of 35 m2 increases the building indoor air temperature of approximately 5 °C which is corrected by the heat insulation optimization of the false ceiling made up with building local materials. The final indoor air temperature obtained is in good agreement with the ASHRAE standards and can, therefore, be applied to tropical regions.
Renewable Energy Resources and Technologies
Babak Tohidi; Majid Delshad; Hadi Saghafi
Abstract
A new interleaved high step-up converter with Zero Voltage Transition (ZVT) is proposed for operation in this paper. The main advantages of the proposed converter are low input current ripple and low voltage stress on the power switches, high efficiency, low total component count, and eliminating reverse ...
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A new interleaved high step-up converter with Zero Voltage Transition (ZVT) is proposed for operation in this paper. The main advantages of the proposed converter are low input current ripple and low voltage stress on the power switches, high efficiency, low total component count, and eliminating reverse recovery problem of power diodes. Due to the soft switching operation of the switches and diodes in the converter, the efficiency has been enhanced. Also, the switches do not have capacitive turn on loss due to ZVT operation. The proposed converter uses only one power switch to provide ZVT conditions for all switches and the clamp capacitor transfers its energy to the lifting capacitor, which causes increase in voltage gain of the converter. Because of the interleaved structure, the converter has a low input ripple current and this advantage makes it very suitable for solar applications. The proposed converter is analysed and a 580W prototype is made to verify theoretical analyses.
Renewable Energy Resources and Technologies
Hemad Zareiforoush; Adel Bakhshipour; Iraj Bagheri
Abstract
Drying process is an important post-harvest stage of food crops production which accounts for about 20 % of the world’s energy consumption in the industrial sector. One of the effective ways to reduce the share of fossil fuel consumption in the food drying process is to develop new drying systems ...
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Drying process is an important post-harvest stage of food crops production which accounts for about 20 % of the world’s energy consumption in the industrial sector. One of the effective ways to reduce the share of fossil fuel consumption in the food drying process is to develop new drying systems based on the use of renewable energy sources. In this research, a novel solar-assisted multi-belt conveyor dryer was developed and its performance was analysed. The required thermal energy for drying process was supplied by the combination of solar-gas water heaters and four solar-powered infrared (IR) lamps. The experimental factors included the speed and temperature of the drying air and the power of IR lamps. The performance characteristics were drying time, Overall Specific Energy (OSE), Non-Solar Specific Energy (NSE), Overall Energy Efficiency (OEE), and Solar-Assisted Energy Efficiency (SEE). The optimization process of the drying system was carried out using Response Surface Methodology (RSM) by defining two general modes for the energy sources of the drying system, namely overall mode and solar-assisted mode. Based on the results, the lowest OSE (17.30 MJ/kg water evaporated) was obtained when the speed and temperature of the drying air were equal to 7 m/s and 40 °C, respectively, without using IR power. The lowest NSE (2.71 MJ/kg water evaporated) was achieved by applying the treatment of 7 m/s * 40 °C * 300 W. The maximum OEE was equal to 13.92 % whilst the maximum SEE was obtained as 88.71 %. Both of the mentioned maximum values were obtained at the speed and temperature combination of 7 m/s and 40 °C and their difference was applying 300 W IR power to gain maximum SEE and no IR utilization for the maximum OEE. According to RSM analysis, the optimum working conditions for the drying system included the treatment of 7 m/s * 39.96 ºC * 300 W. Under this condition, the drying time, NSE, and SEE values were equal to 180.95 min, 1.062 MJ/kg water evaporated, and 84.63 %, respectively.
Renewable Energy Resources and Technologies
Shiva Shadpour; ALi Pirouzi; Mohsen Nosrati; Hoda Hamze
Abstract
Long mixing time, high power consumption, and small mass transfer coefficients are common problems in the photobioreactor design for microalgae culture which have a great effect on system efficiency and performance, CO2 stabilization, and biomass production. In this study, a special design of the triangular ...
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Long mixing time, high power consumption, and small mass transfer coefficients are common problems in the photobioreactor design for microalgae culture which have a great effect on system efficiency and performance, CO2 stabilization, and biomass production. In this study, a special design of the triangular external loop airlift photobioreactor was studied. The bioreactor's geometry was such that the angle between hypotenuse and the horizontal side ( ) could vary. This configuration created an effective gas-liquid countercurrent flow in the downcomer section. In the present research, hydrodynamic and mass transfer of the reactor were investigated on the microalgae productivity under different design and operating parameters. The optimum conditions for the enhancement of Chlorella vulgaris productivity were explored by analyzing the mixing time ( ), volumetric power consumption (P/V), mass transfer coefficients ( ), bubble diameter (d), and gas holdup ( ) as responses. The results showed that the hypotenuse angle of = 59o and the superficial gas velocities of the = 0.0050 m.s-1 for the downcomer and = 0.008 m.s-1 for the riser of the reactor were the best conditions to achieve the highest biomass productivity. The responses’ values obtained in the optimum condition were as follows: = 19.67 (h-1), = 23.79 (h-1), = 23.76 (h-1), = 0.41, and = 62.83 , which had a smaller deviation than the actual values. The highest concentration of Chlorella vulgaris ( 1.4 g.l-1) achieved in this work was obtained in a shorter span of time (11th day of cultivation) based on the growth curve in optimized conditions.
Renewable Energy Resources and Technologies
Sina Eterafi; Shiva Gorjian; Majid Amidpour
Abstract
In this study, the effect of covering the aperture area of a conical cavity receiver with an ultra-white glass on operational parameters of a Parabolic Dish Collector (PDC) was numerically and experimentally investigated under climate conditions of Tehran (35.44° N latitude and 51.10° longitude). ...
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In this study, the effect of covering the aperture area of a conical cavity receiver with an ultra-white glass on operational parameters of a Parabolic Dish Collector (PDC) was numerically and experimentally investigated under climate conditions of Tehran (35.44° N latitude and 51.10° longitude). The main components of the experimental setup include a dish reflector, a conical cavity receiver, Heat Transfer Fluid (HTF), hydraulic and cooling cycle, and a sun tracker. For this purpose, a conical cavity receiver with an ultra-white glass cover on its aperture was numerically modeled in Fortran software. During the evaluation, environmental parameters including ambient temperature, solar radiation, and wind speed were considered as inputs of the model. The results revealed fair agreement between the numerical and experimental data with the maximum error of approximately 4.63 % and 7.89 % for receivers with and without the glass cover on the aperture, respectively. For a steady-state analysis, the mean values of useful energy ( ) absorbed by the receiver were calculated as 1,253.25 W and 987.68 W, while thermal efficiency ( ) of the receiver was calculated as 52.61 % and 40.69 % for receivers with and without glass cover, respectively. The results revealed that both and followed a similar trend of the variations in the HTF’s temperature between the inlet and outlet of the receiver. Also, the overall heat loss coefficient ( ) and the collector heat removal factor ( ) were calculated as 420.76 W/m2°C and 0.62 for the conical cavity receiver with the glass cover.
Renewable Energy Resources and Technologies
Najmeh Salehi; Arash Mirabdolah Lavasani; Ramin Mehdipour; Mohammad Eftekhari Yazdi
Abstract
One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others ...
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One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others lies in our attempt at applying a new method for calculating critical heat flux based on Look-up Table. In the current study, effects of nanofluid on the length of the critical heat flux and convection heat transfer coefficient were investigated. The nanoparticles considered in this study were aluminum, silver, nickel, and titanium dioxide at concentrations of 0.01, 0.1, 0.3, 0.5, 1 and 2 %. Modeling results revealed that the heat transfer coefficient increased upon enhancing the volumetric concentration of nanoparticles, thereby improving this coefficient at 2 vol. % nickel nanoparticles, which was 10.6 % above the value of pure water. On the other hand, thermal efficiency was enhanced when nickel nanoparticles were dispersed in pure water such that increase rates of thermal efficiency equaled 11.2, 10.8 and 11.3 % in the months of June, July, and August, respectively, when the volume concentration of nanoparticles was 0.5 %.
Renewable Energy Resources and Technologies
Daryoosh Borzuei; Seyed Farhan Moosavian; Abolfazl Ahmadi; Rouhollah Ahmadi; Kourosh Bagherzadeh
Abstract
Energy plays a vital role in all human life activities. Due to the problems caused by fossil fuels in recent decades such as global warming, greenhouse gas emissions, ozone depletion, etc., the use of renewable and clean energy has been considered. An experimental facility for the acquisition of reliable ...
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Energy plays a vital role in all human life activities. Due to the problems caused by fossil fuels in recent decades such as global warming, greenhouse gas emissions, ozone depletion, etc., the use of renewable and clean energy has been considered. An experimental facility for the acquisition of reliable data from Parabolic Trough Solar Collectors (PTCs) was established to develop a robust analytical model. A wide range of Heat Transfer Fluid (HTF) flow rates (0.0372-0.1072 kg/s) and solar radiation (400-900 W/m2) were used to determine PTC parameters such as the outlet temperature of HTF loss and temperature distribution. Vacuum conditions in the receiver were considered effective in terms of thermal efficiency. Also, three types of HTF including two oil fluids (Syltherm 800 and S2) and water were examined. The temperature distribution showed that when Syltherm 800 or S2 passed through the absorber tube, the outlet temperature was higher than water: 2.84 % for Syltherm 800 and 3.72 % for S2. Since the absorber tube temperature was much higher than water, the heat loss in this condition was considered for oil HTF. Of note, the results demonstrated that use of the vacuum tube could diminish heat loss for the oil HTF. The effect of solar intensity increases from 600 W/m2 to 900 W/m2 on the maximum temperature of the receiver tube indicated that when Syltherm 800 was used as an HTF, this temperature increased by 35.1 % (from 167 °C to 219 °C), while this percentage was 32.7 % and 6.8 % for S2 and water, respectively.
Renewable Energy Resources and Technologies
Mehdi Jahangiri; Fatemeh Karimi Shahmarvandi; Reza Alayi
Abstract
The use of small-scale Combined Heat and Power (CHP) to meet the electrical and thermal needs of buildings has grown exponentially and plans have been made in Iran to expand these systems. In view of the above, in the present work, for the first time, sensitivity analysis has been performed on the parameters ...
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The use of small-scale Combined Heat and Power (CHP) to meet the electrical and thermal needs of buildings has grown exponentially and plans have been made in Iran to expand these systems. In view of the above, in the present work, for the first time, sensitivity analysis has been performed on the parameters of natural gas price, annual interest rate, and the price of pollutant penalties. The CHP system studied included fuel cell, biomass generator, solar cell, wind turbine, and gas boiler. The techno-econo-enviro simulations were performed by HOMER software and the study area was Abadan. The use of a dump load to convert excess electricity into heat and heat recovery in a biomass generator and fuel cell are other advantages presented by the present work. The minimum Cost of Energy (COE) is 1.16 $/kWh. The results also showed that the use of biomass generators was economical when the annual interest rate was 30 %. The significant effect of using dump load on the required heat supply and the lowest price per kg of hydrogen produced equal to $ 35.440 are other results of the present work. In general, the results point to the superiority of solar radiation potential over wind energy potential of the study area and the prominent role of dump load in providing heat on a residential scale is clearly seen. Also, for the current situation, using biomass is not cost-effective.
Renewable Energy Resources and Technologies
Stephen Ndubuisi Nnamchi; Onyinyechi Adanma Nnamchi; Kevin Nnanye Nwaigwe; Zaid Oluwadurotimi Jagun; Johnson Ugochukwu Ezenwankwo
Abstract
This study conducts a comparative evaluation of the performance of modules and the arrays under standard test conditions. An equivalent circuit model was developed alongside a computational scheme. The model input data were obtained from the manufacturer’s specification datasheets. They were used ...
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This study conducts a comparative evaluation of the performance of modules and the arrays under standard test conditions. An equivalent circuit model was developed alongside a computational scheme. The model input data were obtained from the manufacturer’s specification datasheets. They were used to analyse the maximum Fill Factor (FF) and Relative Power Losses (RPL) for Parallel (P), Series (S) and Series-Parallel (SP) configurations. For matching modules, the RPL was insignificant, but for mismatched modules, the parallel configuration (P) and series-parallel (SP) yielded RPL of 1.3 %, while the series configuration (S) produced RPL of 2.6 %. Thus, short circuit defects associated with the P and SP configuration were well below the open circuit defects associated with the series configuration (S). These results clearly show that the large photovoltaic plant needs to be configured with multiple blocks or strings of SP configuration in order to suppress RPL. In addition, the designer and installers of large solar power plants should adopt modules with uniform electrical and thermal properties in the construction of large solar power plants. The trivial RPL associated with the matched modules should be taken into consideration, as well.
Renewable Energy Resources and Technologies
Md. Tamim Hossain; Md. Atiqur Rahman; Suman Chowdhury
Abstract
In the context of increasing emission of greenhouse gasses in the environment due to fossil fuel burning, this paper attempts to describe the significance of Maximum Power Point Tracking (MPPT) by investigating the power performance of photovoltaic modules with MATLAB simulation. MPPT algorithm was employed ...
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In the context of increasing emission of greenhouse gasses in the environment due to fossil fuel burning, this paper attempts to describe the significance of Maximum Power Point Tracking (MPPT) by investigating the power performance of photovoltaic modules with MATLAB simulation. MPPT algorithm was employed to secure maximum power from PV module. The boost converter whose pulse is linked to MPPT algorithm restricts the flow of load power and controls the current and voltage of PV panels. The whole design of the solar model, boost converter, and MPPT controlled algorithms was done in the SIMULINK to prioritize the system in simulation. The main concept employed in this paper was to develop a power generation process with MPPT algorithm and to provide information for future use. In this paper, all simulations along with the PV power generation process were done in MATLAB. This research could potentially play a vital role in mitigating the world fuel crisis.
Renewable Energy Resources and Technologies
Nima Amani; Abdul Amir Reza Soroush
Abstract
One of the main reasons of environmental pollution is energy consumption in buildings. Today, the use of renewable energy sources is increasing dramatically. Among these sources, solar energy has favorable costs for various applications. This study examined a commercial building in a hot and humid climate. ...
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One of the main reasons of environmental pollution is energy consumption in buildings. Today, the use of renewable energy sources is increasing dramatically. Among these sources, solar energy has favorable costs for various applications. This study examined a commercial building in a hot and humid climate. The findings showed that choosing the optimal angle of solar panels with the goal of optimized energy consumption would yield reduced costs and less environmental pollutants with the least cost and maximum energy absorption. In this study, to calculate the energy requirements of the building, DesignBuilder software was used. To study the solar angles and estimate the energy produced by the solar panels, Polysun software was used after simulating the building energy. Energy simulation results showed that the whole building energy consumption was 26604 kWh/year. Finally, the evaluation results of solar panels showed that the energy produced by photovoltaic modules at an optimal angle of 31° would be equal to 26978 kWh/year, which is more than the energy required by the building. This system can prevent 14471 kg of carbon dioxide emissions annually. Sustainable energy criteria showed that for the studied building, photovoltaic modules could be used in energy production to reach a zero-energy system connected to the grid with an annual energy balance.
