Mahdi Sharifi; Mohammad Haghighi; Farhad Rahmani; Nader Rahemi
Abstract
Utilization of active and stable catalyst could have enormous advantages in industrial application of biogas reforming. In order to achieve this goal, the effects of Cu and Co as promoters were investigated over physical-chemical properties of Ni/Al2O3-ZrO2 catalyst in reforming of biogas. The sequential ...
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Utilization of active and stable catalyst could have enormous advantages in industrial application of biogas reforming. In order to achieve this goal, the effects of Cu and Co as promoters were investigated over physical-chemical properties of Ni/Al2O3-ZrO2 catalyst in reforming of biogas. The sequential impregnation was used for preparation of catalysts. The catalysts were characterized using XRD, FESEM, BET and FTIR analysis. The XRD patterns displayed that the active phases promoters could be effective on nanoparticles dispersion. The FESEM images showed that uniformity of particles size was improved for bimetallic catalysts in comparison with Ni/Al2O3-ZrO2 catalyst but the specific surface areas had no significant change in BET analysis. Higher content of –OH structural groups on surface of Ni-Co/Al2O3-ZrO2 catalyst were proved by FTIR characterization. The performances of catalysts were assessed at atmospheric pressure, feed gas ratio of CO2/CH4= 1, GHSV=24 l/g.h and temperature ranges from 550-850°C. The results revealed Ni-Co/Al2O3-ZrO2 catalysts had the best activity. Because of optimized operating condition and application of ZrO2 as a promoter, the activities of all catalysts remained stable at 850°C for 24 h.
Imologie Simeon; Raji O. A.; Agidi Gbabo; Cynthia Okoro-Shekwaga
Behzad Aghabarari
Abstract
In this study, Functionalized chitosan with amine groups was synthesized and coated on the surface of carbon black. The hybrid amino functionalized chitosan-carbon support was employed as an efficient, environmentally friendly heterogeneous catalyst for the transesterification reaction of canola oil ...
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In this study, Functionalized chitosan with amine groups was synthesized and coated on the surface of carbon black. The hybrid amino functionalized chitosan-carbon support was employed as an efficient, environmentally friendly heterogeneous catalyst for the transesterification reaction of canola oil and methanol. It was observed that this hybrid was more active than parent polymer at the reaction condition. Furthermore, the reactionparameters, such as reaction temperature, molar ratio, amount of the catalyst and reaction time were studied. It was shown that the conversion of canola oil to methyl esters could reach to 95 % during 3.5 h when the reaction was performed with the molar ratio of methanol to canola oil of 12, a catalyst amount of 5 Wt.%, at the reaction temperature of 60 C. These results can be explained by the inherent basicity of amines groups of amino functionalized chitosan on the surface of carbon support. This novel heterogeneous catalyst offers several attractive advantages such as high catalyst activity, easy recovery and reusability of the catalyst.
Renewable Energy Resources and Technologies
Abir Hmida; Abdelghafour Lamrani; Mamdouh El Haj Assad; Yashar Aryanfar; Jorge Luis Garcia Alcaraz
Abstract
Around the globe, a 60 % increase in energy demand is predicted to occur by the end of the year 2030 due to the ever-increasing population and development. With a registered temperature up to 50 °C in August 2020, which is classified as one of the hottest regions in the world, the demand for cool ...
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Around the globe, a 60 % increase in energy demand is predicted to occur by the end of the year 2030 due to the ever-increasing population and development. With a registered temperature up to 50 °C in August 2020, which is classified as one of the hottest regions in the world, the demand for cool temperatures in Gabes-Tunisia to achieve the thermal comfort of people ensuring the product storage has become more and more intense. Removing heat from buildings represents the most extensive energy consumption process. In this paper, an absorption-refrigeration system driven by solar energy is proposed. A parametric simulation model is developed based on the TRNSYS platform. A comparison between different models for global radiation calculation and experimental meteorological data was carried out. It has been proven that the Brinchambaut model seems to be the most convenient in describing the real global radiation, with an error of up to 3.16 %. An area of 22 m² of evacuated tube solar collector ensures the proper functioning of the generator and achieves a temperature up to 2 °C in the cold room.
Advanced Energy Technologies
Mohammad Saleh Barghi Jahromi; Vali Kalantar; Mohammad Sefid; Masoud Iranmanesh; Hadi Samimi Akhijahani
Abstract
Paraffin waxes are widely used as commercial organic heat storage phase changes (PCM) for many applications due to their suitable properties. Significant heat from fusion, nonpoisonous and stable properties, no phase separation, and the phase process result in a small volume change. Meanwhile, they are ...
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Paraffin waxes are widely used as commercial organic heat storage phase changes (PCM) for many applications due to their suitable properties. Significant heat from fusion, nonpoisonous and stable properties, no phase separation, and the phase process result in a small volume change. Meanwhile, they are subject to low thermal conductivity. The thermal conductivity of PCMs can be increased by different techniques such as the use of dispersion of particles or nanomaterials with high conductivity in PCM and the use of metal foams. The use of nanoparticles has such disadvantages as high cost and particle deposition after various cycles. Hence, in this study, some experiments were carried out to investigate the effect of porous media like copper foam and iron wool as the filler instead of nanomaterials on improving the heat conductivity of PCM. The results show that the porous foam increases the heat transfer and during the charging operation, the temperature of the porous plate wall increases continuously at the same rate as the paraffin. At 2400 s, the temperature of pure PCM, iron wool, and copper foam reaches 67.3, 72.5, and 73.27℃, respectively. The optimal mode is the one in which the copper absorber plate is connected to the copper foam, thus reducing the charging time by 600 s compared to pure PCM and saving 75% of energy. Connecting the copper absorber plate to the iron wool has a good thermal performance and stores 70.83% of energy. Thus, iron wool has an acceptable performance and is suitable for storage systems.
Renewable Energy Resources and Technologies
Mahdi Pourbafrani; Hossein Ghadamian; Mohammad Aminy; Meisam Moghadasi; Masoud Mardani; Mohammad Akrami; Amir houshang Khaki; Seyed Mohammad Kazem Sadr
Abstract
Evacuated tube solar collectors (ETSC) are widely utilized in both domestic and industrial solar water heaters (SWH) due to their commendable thermal performance and straightforward installation. However, a significant challenge associated with ETSC lies in the fact that half of the collector remains ...
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Evacuated tube solar collectors (ETSC) are widely utilized in both domestic and industrial solar water heaters (SWH) due to their commendable thermal performance and straightforward installation. However, a significant challenge associated with ETSC lies in the fact that half of the collector remains unexposed to sunlight. To overcome this limitation, parabolic reflectors can be employed as a viable solution. The primary objective of this study is to assess the performance of a compound parabolic concentrator (CPC) in conjunction with ETSC, taking into account a specific ratio between the areas of the CPC and ETSC. To achieve the desired configuration, the CPC was meticulously designed, fabricated, installed, and subsequently tested. Moreover, the energy performance of the absorber tube was scrutinized both with and without the integration of a parabolic trough collector. The experiments and data collection were conducted on two selected days for both the conventional ETSC device and the system incorporating the CPC. Meteorological data and operational conditions were measured and digitally stored for subsequent analysis. A noteworthy outcome of the study is the revelation that the energy efficiency of the system with a concentrator exhibited a notable improvement of 2.8% compared to the conventional system. Offline results further indicated that the performance of a single absorber tube with a concentrator increased by approximately 2.7 times when compared to the standard system. This suggests that the energy performance of the solar water heater, with a capacity of about 200 liters and featuring 7 absorber tubes with a concentrator, is comparable to that of the conventional system equipped with 18 absorber tubes.
Renewable Energy Resources and Technologies
Amir Hossein Zare; Esmail Mahmoodi; Mohsen Boojari; Ali Sarreshtehdari
Abstract
Significant growth of the wind power market has led to a dramatic increase in the scale and capacity of wind turbines over the past decades. As these extreme-scale structures are expected to pose a wide range of challenges, an innovative concept which both lightens blade's mass and improves their aerodynamic ...
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Significant growth of the wind power market has led to a dramatic increase in the scale and capacity of wind turbines over the past decades. As these extreme-scale structures are expected to pose a wide range of challenges, an innovative concept which both lightens blade's mass and improves their aerodynamic performance, is vital for the future of rotor's design. In the present study, modeling and evaluating of an innovative pre-aligned rotor design based on SANDIA SNL100-00 wind turbine blade were accomplished. To evaluate the aerodynamic performance of the proposed rotor, CFD simulation was used as a well-developed technique in fluid mechanic. In the new rotor design, the swept area was increased using an equal blade length and the blade sections were more appropriately aligned with the wind flow compared to the reference model. This enhancement attained due to transferring the bending position from the root to a certain point alongside the length of blade. According to simulation assessments, this modification led to the overall improvement of main performance parameters in terms of the mean power and the applied torque on the blades. The simulation revealed that the novel concept is capable of increasing the mean power coefficient by 13.21 % compared to the conventional rotor designs. Analysis of the axial induction in front of the rotor plane displayed a greater drop in the flow velocity streaming up to the rotor, which could lead to have a more efficient configuration for harnessing the upcoming wind's power.
Zahra Najafgholi; Mostafa Rahimnejad; Ghasem Najafpour
Abstract
Sediment microbial fuel cells (SMFCs) are a promising technology for a viable source of energy. This technology is faced with many challenges, such as limited mass transfer and low electricity generation. The aim of this research was to investigate the effect of electrolyte conductivity and aeration ...
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Sediment microbial fuel cells (SMFCs) are a promising technology for a viable source of energy. This technology is faced with many challenges, such as limited mass transfer and low electricity generation. The aim of this research was to investigate the effect of electrolyte conductivity and aeration effect on power generation from SMFCs. Electrical conductivity was adjusted at 6different levels by adding several concentrations of NaCl and KCl, which are abundant and economic salts. By adding NaCl, the performance of SMFCs improved about 3.25 fold. Maximum generated power and current density of 32.76 mW/m2 and 330.14 mA/m2are obtained,respectively afterNaCl addition. Also, with aeration dissolved oxygen level increased as an electron acceptor in cathode portion, thereby power density enhanced from 16.36 mW/m2 to 38.31 mW/m2which was a 234% increase compared to the situation before aeration.
Sajad Rostami; Bahram Hosseinzadeh Samani; Keramatolah Saeidi
Abstract
Renewable energy sources are developed worldwide, owing to high oil prices and in order to limit greenhouse gas emissions. The objective of this research was to study the feasibility of biodiesel production from mountain almond (Prunus Scoparia) oil using ultrasonic system and optimization of the process ...
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Renewable energy sources are developed worldwide, owing to high oil prices and in order to limit greenhouse gas emissions. The objective of this research was to study the feasibility of biodiesel production from mountain almond (Prunus Scoparia) oil using ultrasonic system and optimization of the process using Artificial Bees Colony (ABC) Algorithm. The results showed that by increasing the molar ratio, the conversion percentage increased and after reaching a certain ratio, further increase in the molar ratio caused decrease in the conversion percentage. Increasing in the ultrasound amplitude resulted in an increase in the conversion percentage which tends to ascend; Furthermore, results of optimization showed that the amount of molar ratio, amplitude, pulse and reaction time were 5.6, 0.90, 0.33 and 5 min, respectively. For independent variables, the values of yield and energy consumption were obtained which were equal to 96.1% and 9912 J, respectively. This finding proves that ABC algorithm can estimate the optimum point in biodiesel production with high accuracy. Renewable energy sources are developed worldwide, owing to high oil prices and in order to limit greenhouse gas emissions. The objective of this research was to study the feasibility of biodiesel production from Mountain almond (Prunus scoparia) oil using ultrasonic system and optimization of the process using Artificial Bees Colony Algorithm. The results showed that with increasing the molar ratio, the conversion percentage increased and after reaching a certain ratio, further increase in the molar ratio caused decrease in the conversion percentage. The increase in the ultrasound amplitude resulted in an increase in the conversion percentage which tends to ascend. Furthermore, results of optimization showed that the amount of molar ratio, amplitude, pulse and reaction time were 5.6, 0.90 0.33 and 5 min, respectively. For independent variables, the values of yield and energy consumption were obtained which were equal to 96.1% and 9912 J, respectively. This finding proves that ABC algorithm can estimate the optimum point in biodiesel production with high accuracy.
Mohammad Zarei-Jelyani; Mohsen Babaiee; Abdolmajid Ghasemi; Rahim Eqra
Abstract
Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in ...
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Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in VOSO4 solution with an optimized supporting electrolyte (a mixture of six parts HCl and 2.5 parts H2SO4). Carbon felt electrode was hydroxylated with mixed acids of H2SO4 and HNO3 in a stainless steel autoclave for 6 h. Then thermal treatment of electrode was performed at 400 oC for 5h. Obtained results of cyclic voltammograms showed that when the carbon felt was hydroxylated, both oxidation and reduction peak currents were increased remarkably and the peak potential separation is decreased from 356 mV to 246 mV, suggesting that the electrochemical activity and the kinetic reversibility on HCF electrode were improved compared to the pristine one. According to results of electrochemical impedance spectra, charge transfer resistance (Rct) was calculated to be 648 Ω for pristine carbon felt. The obtained Rct at hydroxylated electrode (176 Ω) shows a decrease of about 73 % in Rct. Charge-discharge profiles of two cells assembled with the pristine carbon felt (cell A), and hydroxylated carbon felt (cell B) showed that energy, voltage and coulombic efficiencies were significantly improved by using the hydroxylated electrodes inside the cell of vanadium redox flow battery.
Morteza Keshavarz; Behnam Mostajeran Goortani
Abstract
The amine regenerator of acid removal unit in South Pars Gas Complex, Assalouyeh, Iran was modeled. This model was fitted to assess the large scale columns and allow application of solar thermal energy for production of low pressure steam. Heat transfer fluids including Therminol oil, sulfur, or salt ...
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The amine regenerator of acid removal unit in South Pars Gas Complex, Assalouyeh, Iran was modeled. This model was fitted to assess the large scale columns and allow application of solar thermal energy for production of low pressure steam. Heat transfer fluids including Therminol oil, sulfur, or salt melt could be applied to yield thermal energy from a solar collector and to store and transfer it to the reboiler of columns. The Angstrom model was adopted here to simulate solar irradiance. Solar irradiance data for the city of Assalouyeh, during the years of 2009-2014, were collected and applied. The results indicated that based on a reboiler duty of around 21.8 MW, a solar collector area of 148,000 m2 was required with a mass of heat transfer and storage medium of 1247255 kg oil, 1787732 kg salt melt and 3803686 kg sulfur, respectively. This model was applied as an analytical tool to explore and describe the following two problems encountered during real plant operation: fouling in the amine heat exchangers and increasing regenerator pressure.
Renewable Energy Economics, Policies and Planning
Vasundhara Sen
Abstract
Despite the falling costs of Renewable Energy (RE), RE adoption in Indian residential households is still attepid growth rates. With the onset of retail electricity market deregulation in India, the introduction of “greentariffs” for residential households can be effective in resolving the ...
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Despite the falling costs of Renewable Energy (RE), RE adoption in Indian residential households is still attepid growth rates. With the onset of retail electricity market deregulation in India, the introduction of “greentariffs” for residential households can be effective in resolving the issue of low RE adoption. This studyinvestigates the willingness to pay for green tariffs/renewable energy-based electricity contracts using thecontingent valuation method. Data collected from 476 Indian residential households are analyzed by theDouble-Bounded Dichotomous Choice technique. The results of the conducted maximum LikelihoodEstimation (MLE) method reveal the mean willingness to pay 308.52 Rs per household/month for consumption of green power in a premium-paying setting. Results indicate that although households hold positive perception of renewable energy, the willingness to pay is not commensurately high, indicating an attitude-action gap. The study recommends green energy defaults in residential energy contracts, direct marketing of non-use value of RE use (altruistic and bequest) by power supplying utilities, and promoting RE use through RE opinion champions/influencers as measures to enhance RE adoption amongst Indian residential energy consumers.
Mona Iravaninia; Sousan Rowshanzamir
Abstract
In present research work, anion exchange membranes based on quaternized polysulfone with ammonium cation moieties (QAPSF) were prepared by chloromethylation, amination and alkalization. The chloromethylated polysulfone were characterized by 1HNMR spectroscopy and functionalization degree was determined ...
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In present research work, anion exchange membranes based on quaternized polysulfone with ammonium cation moieties (QAPSF) were prepared by chloromethylation, amination and alkalization. The chloromethylated polysulfone were characterized by 1HNMR spectroscopy and functionalization degree was determined according to peak area integration. Ion transport properties (ionic conductivity, ion exchange capacity, activation energy for ion transport) and water content associated properties (water uptake, swelling ratio, hydrated number) were measured for the prepared anion exchange membranes. The ion exchange capacity for these membranes varied from 0.96 to 1.73 meq/gr while the degree of chloromethylation increased from 82% to 143%. The membrane with IEC value of 1.73 meq/gr showed the highest ionic conductivity in the range of 15.87-34.01 mS/cm at 25-80 °C. The activation energy for ion transport, water uptake and swelling ratio of this membrane were measured to be 11.99 kJ/mol, 37.41% and 14.71%, respectively which demonstrated the reasonable performance of the prepared anion exchange membranes. Based on the obtained results, prepared anion exchange membranes could be proposed as good candidates for solid alkaline fuel cells.
Afshin Lashkar Ara; rahil hosseini; Hajar Bagheri Tolabi
Abstract
In this paper, a novel approach for the estimation of global solar irradiance is proposed based on a combination of empirical correlation and ant colony optimization. Empirical correlation has been used to estimate monthly average of daily global solar irradiance on a horizontal surface. The Ant Colony ...
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In this paper, a novel approach for the estimation of global solar irradiance is proposed based on a combination of empirical correlation and ant colony optimization. Empirical correlation has been used to estimate monthly average of daily global solar irradiance on a horizontal surface. The Ant Colony Optimization (ACO) algorithm has been applied as a swarm-intelligence technique to tune the coefficients of linear and nonlinear empirical models. . The performance of the models is investigated for the estimation of global solar irradiance at four different climatic regions of Iran based on statistical indicators like coefficient of determination (R2) and root mean square error (RMSE). The results obtained from the proposed model are superior in comparison with the other well established models.
Advanced Energy Technologies
Vahid Nazari; Mohammad Hossein Mousavi; Hassan Moradi CheshmehBeigi
Abstract
Over the past decades, power engineers have begun to connect power grids to other networks such as microgrids associated with renewable units using long transmission lines to provide higher reliability and greater efficiency in production and distribution besides saving resources. However, many dynamic ...
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Over the past decades, power engineers have begun to connect power grids to other networks such as microgrids associated with renewable units using long transmission lines to provide higher reliability and greater efficiency in production and distribution besides saving resources. However, many dynamic problems such as low frequency oscillations were observed as a result of these connections. Low frequency oscillation is a normal phenomenon in most power systems that causes perturbations and, thus, the grid stability and damping process are of paramount importance. In this paper, to attenuate these oscillations, a novel method for designing Power System Stabilizer (PSS) is presented via Linear Parameter-Varying (LPV) approach for a Single Machine Infinite Bus system (SMIB). Because the system under study is subject to frequent load and production changes, designing the stabilizer based on the nominal model may not yield the desired performance. To guarantee the flexibility of the stabilizer with respect to the aforementioned issues, the power system polytopic representation is used. In order to apply the new method, the nonlinear equations of the system at each operating point, located in a polytope, are parametrically linearized by scheduling variables. Scheduling variables can be measured online in any operating point. By using this model and following the H∞ synthesis, feedback theories, and Linear Matrix Inequalities (LMIs), LPV controllers at all operating points are obtained. Finally, the simulation results verify the effectiveness of the proposed controller over classic and robust controllers with regard to uncertainties and changes in system conditions.
Advanced Energy Technologies
Mohammad Rahimzadeh; Hamid Samadi; Nikta Shams Mohammadi
Abstract
Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters ...
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Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters of these devices. In addition, improved performance is often achieved by operating at or near the resonance point. So, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. For this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. These parameters include the length, thickness, density, and Young’s modulus of each layer. The beam is considered a unimorph cantilever with rectangular configuration and the study is performed using COMSOL Multiphysics software. The results are compared with those obtained by an analytical approach. The results show that changing the parameters made the natural frequency of the system vary in the range of 20 Hz to 200 Hz and increased the output voltage up to 20 V.
Shoeleh Vahdatpour; Shokoofeh Behzadfar; Leila Siampour; Elahe Veisi; Mehdi Jahangiri
Abstract
Renewable systems influence the process of supplying domestic electricity demands. It will be useful to replace the conventional energy generation system by renewable energy sources since the uncontrolled use of fossil fuels is accompanied by global warming and environmental hazards, in addition ...
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Renewable systems influence the process of supplying domestic electricity demands. It will be useful to replace the conventional energy generation system by renewable energy sources since the uncontrolled use of fossil fuels is accompanied by global warming and environmental hazards, in addition to the danger of their depletion, and because most of the energy derived from these fuels are used in buildings. Economical renewable energy systems have not yet been studied in each climate of Iran. Considering the historical background and the potential biomass of Iran, the potential of using a hybrid solar cell/wind turbine/biomass system for supplying the electricity demands of a residential building in each of the four climate regions of Iran has been studied by using HOMER software in this paper. HOMER software has been determined the most cost-efficient system for each region by using the solar radiation and wind speed data, which are acquired over 20 years. By considering economic issues, results indicate that usage of solar cells is the ideal option for the cold, hot dry and warm humid climates (Total net present cost (NPC) and cost of electricity (COE) are $11639 and 1.808 $/kWh, respectively). Also, usage of systems based on biomass is the best choice for the moderate and humid climates (total NPC and COE are $13211 and 2.052 $/kWh, respectively for Babol and $13075 and 2.031 $/kWh, respectively for Chalous).
Shahab Alizadeh; Hamid Reza Haghgou
Abstract
In a 10-ton capacity pilot plant solar liquid desiccant air conditioner (LDAC) developed, dehumidification of the outside air is achieved through a honeycomb packed-bed heat and mass exchanger, using lithium chloride solution as the desiccant. The dry air obtained from the dehumidification process is ...
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In a 10-ton capacity pilot plant solar liquid desiccant air conditioner (LDAC) developed, dehumidification of the outside air is achieved through a honeycomb packed-bed heat and mass exchanger, using lithium chloride solution as the desiccant. The dry air obtained from the dehumidification process is evaporative cooled inside a cooling pad and directed into the conditioned space. The dilute solution thus produced is concentrated in a honeycomb packed-bed scavenger air regenerator using hot water from flat plate solar collectors. Carryover of the desiccant particles has been avoided by using eliminators. The air conditioner was installed on a 250 m2 area of the fluid mechanics laboratory of Babol University of Technology, a hot and humid location in the north on the Caspian Sea. The experimental data obtained were compared with the predicted results of a model developed for the air conditioner based on HYSIS and CARRIER energy soft-wares. The comparison reveals that good agreement exists between the experiments and the model predictions. The above tests further reveal that the unit has a satisfactory performance in independently controlling the air temperature and humidity of the conditioned space. The inaccuracies are well within the measuring errors of the temperature, humidity and the air and solution flow rates. An efficient heat recovery within the air conditioner resulted in a thermal COP of about 1.5 and an electrical COP of 7. A commercialization study reveals that the operating cost of an LDAC is significantly lower than its conventional counterpart. The costs would further reduce if a storage system was used to store the concentrated solution of liquid desiccant. A simple payback of five years was determined for the solar components of the liquid desiccant system in this study.
Mahmoud Samadpour; Mehdi Molaei
Abstract
CdSe quantum dots were in situ deposited on various structures of TiO2 photoanode by successive ionic layer adsorption and reaction (SILAR). Various sensitized TiO2 structures were integrated as a photoanode in order to make quantum dot sensitized solar cells. High power conversion efficiency was obtained; ...
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CdSe quantum dots were in situ deposited on various structures of TiO2 photoanode by successive ionic layer adsorption and reaction (SILAR). Various sensitized TiO2 structures were integrated as a photoanode in order to make quantum dot sensitized solar cells. High power conversion efficiency was obtained; 2.89 % (Voc=524 mV, Jsc=9.78 mA/cm2, FF=0.56) for the cells that sensitized by SILAR method. Also all the cells, showed rather high efficiencies (more than 2.65%) regardless of their structure. Here we did the SILAR deposition in room temperature by a simple method which introduces it as a cost effective method for large scale production. Regarding the considerable efficiencies which obtained here by simple SILAR method for various structures, pointed out that SILAR deposition, can be introduced as an effective method for sensitizing electrodes by QDs, in quantum dot sensitized solar cells.
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.
Advanced Energy Technologies
Abraham Olatide Amole; Adebimpe Oluwaseun Adeyeye; Daniel Oluwaseun Akinyele; Kehinde Adeleye Makinde; Stephen Oladipo
Abstract
The use of Diesel Generators (DGs) and gas turbines to power oil rigs is characterized by pollution due to the emission of harmful gases like carbon dioxide, very high noise levels, high maintenance costs, and the inability to start the platform if the DG fails. Offshore wind energy generation system ...
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The use of Diesel Generators (DGs) and gas turbines to power oil rigs is characterized by pollution due to the emission of harmful gases like carbon dioxide, very high noise levels, high maintenance costs, and the inability to start the platform if the DG fails. Offshore wind energy generation system provides a viable alternative means of powering the oil rig and can also be integrated to operate in parallel with gas turbines. However, offshore wind energy might fail if not properly designed due to the high variability of wind resources. Hence, the objective of this work is to design offshore Wind Turbine Generator (WTG) energy generation system, DG, and hybrid DG-WTG for the black start of an offshore oil rig. The designed energy systems are simulated using HOMER Pro. Furthermore, the performance of the simulated systems was evaluated using the electrical production, unmet load, and emission profile as the performance metrics. The results of the hybrid DG-WTG powered black start revealed that 150kW DG generated 322,071kWh/yr representing 6.77% of the total generation and 1.5MW WTG generated 4,434,632kWh/yr representing 93.2% of the total generation. The comparison of the emissions from DG and DG-WTG revealed that 294,058kg/yr, 1,945kg/yr, 80.9kg/yr, 9.02kg/yr, 720kg/yr, and 688kg/yr of CO2, CO, UH, PM, SO2, and NO, respectively, were released into the atmosphere by DG-WTG which is very low compared to 969,129kg/yr, 6,109kg/yr, 267kg/yr, 37kg/yr, 2373kg/yr, and 5739kg/yr of CO2, CO, UH, PM, SO2, and NO, respectively, released into the atmosphere by DG. The sensitivity analysis revealed that while the electrical production of 100kW and 50kW DGs decreased with an increase in WTG height, the electrical production of 1.5MW WTG increased with an increase in WTG height. It was further revealed that the higher the WTG height the smaller the quantity of the emission released into the atmosphere.
Renewable Energy Resources and Technologies
Ahmed H. Mohammed; Ahmed N. Shmroukh; Nouby M. Ghazaly; Abd Elnaby Kabeel
Abstract
In the present study, a modified pyramid-solar-still (MPSS) with new multiple stepped basin areas was investigated in the weather conditions of Qena, Egypt, at a location of (Latitude: 26.16°, Longitude: 32.71°). Boosting the output of the pyramid solar still is the primary focus of the proposed ...
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In the present study, a modified pyramid-solar-still (MPSS) with new multiple stepped basin areas was investigated in the weather conditions of Qena, Egypt, at a location of (Latitude: 26.16°, Longitude: 32.71°). Boosting the output of the pyramid solar still is the primary focus of the proposed strategy. To achieve this, four basins were built and integrated into the pyramid solar still, with their size increasing in proportion to the surface area of the condensing glass. A 25% increase in basin area per square meter of solar still was achieved compared to conventional pyramid solar still (CPSS) with the same condensing cover area. The thermal performance and productivity of the suggested solar still were demonstrated by developing energy balance equations for temperature components and then analytically computing their solutions. The results showed compatibility between theoretical and experimental results. The highest yields for CPSS were 2524 mL/m2, and for MPSS, they were 3415 mL/m2. The stepped area enhanced the yield by 35.3% compared with CPSS. Moreover, the efficiency of CPSS and MPSS was recorded as 23.5% and 31.7%, respectively. Furthermore, the maximum yield of freshwater was obtained for the northern condensing cover, with the recorded value reaching 1174 mL/m2. Distilled water under the proposed system would cost $0.0179 per liter. Finally, the TDS and pH levels are in accordance with WHO recommendations for the quality of drinking water.
Renewable Energy Resources and Technologies
Ayowumi Rita Soji-Adekunle; Betiku Eriola; Abraham A. Asere
Abstract
This study used ternary substrates consisting of honne, neem, and yellow oleander (HONOYO) oil blend to produce methyl-esters for sustainability of raw materials for biodiesel synthesis. A biomass-based catalyst from calcined mixed agro-wastes consisting of kolanut pod, cocoa pod, and plantain peel ash ...
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This study used ternary substrates consisting of honne, neem, and yellow oleander (HONOYO) oil blend to produce methyl-esters for sustainability of raw materials for biodiesel synthesis. A biomass-based catalyst from calcined mixed agro-wastes consisting of kolanut pod, cocoa pod, and plantain peel ash was employed to transesterify the blend. A two-step method was adopted to convert HONOYO into methyl-esters. Taguchi L9 experimental design tool was used to ascertain the interactive effects of microwave irradiation power (W), Methanol/oil ratio (MeOH), time (min), and agro-wastes synthesized catalyst ASC (wt %) on the yield of methyl-esters from HONOYO. Results demonstrated that at 3:1 MeOH, microwave power of 150 W, ASC of 1.5 wt %, and reaction time of 1 minute, a yield of 80.96 % was achieved. HONOYOB satisfied ASTM D6751 and EN 14214 standards. Performance evaluation of the process input variables suggests weight of ASC as the most significant process parameters for HONOYOB yield. This work authenticates that biomass catalyst from agricultural wastes can adequately be applied to synthesis biodiesel effectively from blends of non-edible oils to supplement fossil diesel.
Advanced Energy Technologies
Mohammad Rasooli Mavini; Hassan Ali Ozgoli; Sadegh Safari
Abstract
In this study, various configurations design of a Heat Recovery Steam Generator (HRSG) are examined to enhance energy efficiency of a Combined Cycle Power Plant (CCPP). A novel approach is used to investigate ten applicable configurations of a dual pressure Heat Recovery Steam Generator HRSG thoroughly ...
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In this study, various configurations design of a Heat Recovery Steam Generator (HRSG) are examined to enhance energy efficiency of a Combined Cycle Power Plant (CCPP). A novel approach is used to investigate ten applicable configurations of a dual pressure Heat Recovery Steam Generator HRSG thoroughly to explore the best practice models from the energy-conserving considerations. Further, a fuel consumption assessment has been conducted to identify the best performance of the cycle and investigate the minimum pollutants released of each Heat Recovery Steam Generator (HRSG) configuration. The results have revealed that four scenarios among ten, have expressed a considerably better performance regarding; fuel consumption, steam production, energy efficiency, and finally yet importantly environmental considerations. Further, it has been found that in comparison to the conventional configuration, not only the selected scenarios have proved almost four times improvement in the low-pressure steam generation, but also 30% fuel consumption saving in supplementary firing has been achieved which has both economic and environmental benefits. Moreover the carbon dioxide saving potential for the best scenario is 51.37 kgCO2 MWh-1 consequently the environmental benefit of it is calculated about 133,418 $ MWh-1.
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.
