Energy
M. Maghsoudizadeh; M. Ameri; E. Jahanshahi Javaran; A. MotamedSadr; A. A. Feili Monfared
Abstract
In recent years, the use of renewable energy sources and investigation on renewable energy have significantly grown. In this research, parabolic trough and linear Fresnel collectors, which are widely used in the field of solar energy, have been investigated from the point of view of exergy. First, the ...
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In recent years, the use of renewable energy sources and investigation on renewable energy have significantly grown. In this research, parabolic trough and linear Fresnel collectors, which are widely used in the field of solar energy, have been investigated from the point of view of exergy. First, the energy balance equations for different components of the collector were solved using numerical methods and the temperature distribution in each component of the collector was obtained. Then the values of exergy destruction in each component of the system were calculated. The comparison of the results obtained in the present work with the results of the previous research showed a good agreement. The results showed that the exergy efficiency in the parabolic trough collector is approximately 1.5 times that of the linear Fresnel reflector. Also, changes in exergy efficiency, exergy destruction of the whole collector, output exergy cost and CO2 emission with increasing solar radiation intensity and fluid mass flow rate for both collectors have been compared and investigated.
Energy
N. Momen; H. Pahlavanzadeh
Abstract
Nowadays, due to environmental concerns and the reduction in fossil fuel resources, biodiesel is being considered as a renewable alternative or supplement to fossil diesel. In this research, the transesterification method was used to produce biodiesel from low-cost and non-edible linseed oil in the presence ...
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Nowadays, due to environmental concerns and the reduction in fossil fuel resources, biodiesel is being considered as a renewable alternative or supplement to fossil diesel. In this research, the transesterification method was used to produce biodiesel from low-cost and non-edible linseed oil in the presence of commercial calcium oxide as the catalyst. In addition, the time-consuming and costly calcination step was omitted and a deep eutectic co-solvent of choline chloride/glycerol (2:1) was used to activate the catalyst. The catalyst characterization was studied using X-ray diffraction(XRD) and Fourier transform infrared (FTIR). To ensure the formation of fatty acid methyl esters (FAME), the purity of FAME in the produced biodiesel was calculated using gas chromatography method. Then, the effect of two reaction parameters of the catalyst and the DES concentration on the FAME purity was investigated at a constant temperature of 65 °C, stirring speed of 500 rpm, reaction time of 180 minutes and the methanol to oil molar ratio of 9.5:1. Finally, the optimal catalyst and the DES concentration were obtained as 10% and 14%, respectively. The effect of temperature and time on the FAME purity was investigated and a kinetic study of the reaction suggested a pseudo-first-order reaction with a rate constant of 0.0311 at 65 °C and activation energy of 22.45 kJ/mol.
Energy
N. Hedayati Goodarzi; M. Rahimi-Esbo
Abstract
Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges ...
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Steam reformers are typically utilized in hydrogen production industry, demanding pressure vessels within methanol reformer systems operating at temperatures between 250-350°C to ensure cost-effectiveness. This characteristic makes them a superior choice for fuel cell systems. However, challenges arise in enhancing hydrogen gas production efficiency while minimizing carbon monoxide emissions. Computational Fluid Dynamics (CFD) has proven effective in addressing these challenges by simulating fluid behavior. This study delves into product production, reactant consumption using CFD, and investigates changes in physical parameters of methanol reformers to optimize their performance. The research involves 140 numerical simulations that examine the relationship between feeds (steam-to-carbon) and various temperatures, aiming to understand the concurrent effect of physical parameters. The results demonstrate that increasing temperature has a more significant impact on hydrogen production compared to increasing the feed ratio. This effect is particularly notable at lower fuel ratios. For example, at a feed ratio of 1, a temperature increase of 11.4°C leads to a substantial 5.4% rise in hydrogen production. However, at a higher feed ratio (1.98), the increase in hydrogen production is only 1.9% with the same temperature increase.
Energy
I. Pishkar; S. M. Beigi
Abstract
With sensitive and important systems in hospitals requiring an uninterrupted power supply, finding solutions for power outages is becoming increasingly crucial. Iran's favorable potential for renewable energy makes wind and solar energy viable options to support hospital electricity needs and contribute ...
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With sensitive and important systems in hospitals requiring an uninterrupted power supply, finding solutions for power outages is becoming increasingly crucial. Iran's favorable potential for renewable energy makes wind and solar energy viable options to support hospital electricity needs and contribute to sustainable development goals. The present work investigates, for the first time, the electricity supply of a part of the Parsian Hospital in Shahrekord using HOMER software. The use of real electricity exchange data with the national grid and the new generation of tree-shaped wind turbines are unique advantages. Results show that an optimal renewable energy-based system consisting of two 1-kW solar cells and a 1-kW electric converter costs $0.111 per kWh and solar cells generate 3% or 2999 kWh/year. The optimal scenario produces 55193 kg of CO2 annually due to national grid electricity use, highlighting the importance of renewable energy adoption in hospitals.
Energy
M. Bagheri; I. Mirzaee; M. Khalilian; V. Mousapour
Abstract
The present study simulates Invelox in a three-dimensional and stable way. The flow regime is turbulent flow and an unorganized grid with 350000 cells was utilized. This work has studied the modeling of invelox with conventional dimensions and four different sizes in the form of four modes for use in ...
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The present study simulates Invelox in a three-dimensional and stable way. The flow regime is turbulent flow and an unorganized grid with 350000 cells was utilized. This work has studied the modeling of invelox with conventional dimensions and four different sizes in the form of four modes for use in a residential building. The numerical data with an error of less than 6% are in good agreement with the available experimental and analytical data. The results show that considering the average velocity of mode 2 with a velocity of 6.54 m/s and a 5% difference from the other two modes, it can be operated in a residential building. It is worth noting that in this investigation, in addition, the effect of dust on the turbine performance was evaluated. The results represent that the oscillation frequency of the blades increases with the increase of the rotational speed. In the case of not considering dust particles on blades, this amount increases by 25%, while considering dust particles with an amount of 0.1%, it increases up to 300%, and this can cause irreparable damage to the turbine as well as the power generation system.
Energy
A. Bozorgi; M. J. Zarei
Abstract
Noise pollution is one of the biggest problems of wind turbines, especially when these turbines are located near residential areas. In this article, the effect of blade thickness is numerically investigated on the noise pollution of an H-type Darrieus wind turbine. The flow is first simulated using the ...
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Noise pollution is one of the biggest problems of wind turbines, especially when these turbines are located near residential areas. In this article, the effect of blade thickness is numerically investigated on the noise pollution of an H-type Darrieus wind turbine. The flow is first simulated using the unsteady Reynolds averaged Navier-Stokes equations and the SST-kω model at the tip speed ratio of 2.64. Then, the noise is calculated using Ffowcs Williams-Hawkings equations. Blade thickness is changed using NACA airfoils from NACA 0008 up to NACA 0024. It is concluded that noise calculation at only one point, known as a routine method in noise investigation of wind turbines, is insufficient to investigate the noise of this turbine. Here, maximum noise in directivity is defined as the criterion of noise pollution. The results show that changing the blade profile of the benchmark turbine from NACA 0021 to NACA 0015 increases the power coefficient from 0.318 to 0.371 and reduces the maximum noise from 95.67 dB (76.35 dB) to 90.19 dB (71.01 dB) at R = 2 m (8m). For NACA 0018, the power coefficient is 0.353, and the maximum noise is 89.78 dB (70.47 dB) at R = 2 m (8m). Overall, the highest output power is for NACA 0015, and the lowest noise pollution is for NACA 0018.
Energy
A. Kamyab; M. Mahmoudi Zarandi; M. Nikpour
Abstract
Yazd is located in a hot-dry region with harsh weather conditions. Houses with an iwan were suitable for establishing comfort conditions in the past. An evaluation of the visual comfort conditions in residential courtyard buildings in Yazd city was carried out by investigating the effects of the depth ...
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Yazd is located in a hot-dry region with harsh weather conditions. Houses with an iwan were suitable for establishing comfort conditions in the past. An evaluation of the visual comfort conditions in residential courtyard buildings in Yazd city was carried out by investigating the effects of the depth of the iwan and the ratio of the adjacent rooms' openings. Research is currently being conducted on an optimal model of the iwan in an effort to facilitate sustainable development and increase the use of such a model in contemporary housing. The effect of the parameters was investigated by simulating models containing different proportions of the iwan and sizes of the window in the Design Builder software. The results indicate that the proportion of the iwan and Window Wall Ratio of the adjacent room's window significantly affects the daylight that penetrates into the rooms. For the purposes of this study, climate-based daylight metrics (CBDMs), such as Useful Daylight Illuminances (UDI) with thresholds of 100–3000 lux and Spatial Daylight Autonomy (sDA) over 300 lux. In models with an iwan depth of 1.5 and above, windows from 20% to 60% WWR have the ability to bring a suitable amount of light into the room. This means that by using the iwan, wider windows can be designed without having glare and adding extra thermal load to the building. Results obtained from this research will provide new insight into the concepts of iwan. Furthermore, findings of this research help architect to design spaces with the utilization of daylight.
Energy
I. U. Siloko; E. Enoyoze
Abstract
Wind is a significant weather variable and its study has gained convincing attention recently due to its increasing importance as a source of renewable energy as well as its role in various natural phenomena like erosion, precipitation, and spread of wildfires. This paper investigates wind speed distribution ...
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Wind is a significant weather variable and its study has gained convincing attention recently due to its increasing importance as a source of renewable energy as well as its role in various natural phenomena like erosion, precipitation, and spread of wildfires. This paper investigates wind speed distribution in Delta State, Nigeria using a nonparametric statistical technique for ten consecutive years spanning from 2011 to 2020 across three stations. The nonparametric statistical approach is the kernel density estimation with focus on Gaussian kernel estimator. The results of the investigated period revealed that wind speed in Asaba that is located in Delta North is higher in comparison with the wind speed in Patani which is situated in Southern region of the State while the wind speed is low at Sapele in Delta Central. Therefore, installation of wind power generation system is more profiting in the Northern part because the amount of wind energy generated is determine by the wind speed. Again, the performance of agricultural or industrial activities that depend on wind speed for their proper execution is optimum in 2018 while the least performances were recorded in 2015 and 2016 respectively for the period explored.
Energy
Z. Aouissi; F. Chabane; M. S. Teguia
Abstract
The study shows an experimental investigation for a solar air collector with a single pass by adding rectangular baffles for different positions inside the channel. The aim of this study is to improve the thermal efficiency for this collector, and that through testing four cases of baffles positions ...
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The study shows an experimental investigation for a solar air collector with a single pass by adding rectangular baffles for different positions inside the channel. The aim of this study is to improve the thermal efficiency for this collector, and that through testing four cases of baffles positions (mode 1, 2, 3, 4). The study was done under different operating conditions by changing the mass flow rates and positions of baffles. The results show the effectiveness of the baffles in improving the efficiency of the collector, The study also proved that the baffles positions affect thermal efficiency, where the greatest efficiency was recorded in the fourth mode and then in the positioning of obstacles at the middle of the channel for the mode 2 and the mode 4 with a percentage of 76.61 and 90.9, at mass flow rate m=0.0522 kg/s, while the pressure drop was very high in the mode 4, and after that the mode 2. Through the conditions of the study and taking into account all the results; we can say that the best case was mode 2.
Energy
A. W. Tahiru; S. U. Takal; E. D. Sunkari; S. Ampofo
Abstract
Although Ethiopia is one of the world's fastest-growing economies, access to sustainable energy and cutting-edge clean energy technology remains a major concern. The government is making significant efforts to generate renewable energy and provide more access to its citizens. Despite this, traditional ...
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Although Ethiopia is one of the world's fastest-growing economies, access to sustainable energy and cutting-edge clean energy technology remains a major concern. The government is making significant efforts to generate renewable energy and provide more access to its citizens. Despite this, traditional fuels (charcoal, fuel wood, dung cakes, and agricultural waste) account for around 87 percent of Ethiopia's energy use, and they pose a range of health and environmental risks. Solar, hydro, wind, and geothermal resources abound in the nation, but only 5% of the country's total hydroelectric capacity is being used; while, the rest is either underutilized or underdeveloped. An in-depth look at Ethiopia's renewable energy potential, as well as the opportunities and problems it faces, is presented in this review. With a combined installed capacity of over 7000 MW, hydropower and wind power are the most promising renewable energy sources in Ethiopia as of yet. It is hoped that this assessment will shed light on how Ethiopia can harness and maximize the use of its abundant renewable energy sources.
Energy
H. Farzan; A. A. Abouee-Mehrizi; M. Khazali
Abstract
The current study introduces and analyzes a novel square cross-flow perforated solar air heater (SAH). Since the convection mechanism in SAHs is weak, numerous methods have been suggested to address this problem and improve thermal efficiency. Perforations and cross-flow configuration generate high turbulency ...
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The current study introduces and analyzes a novel square cross-flow perforated solar air heater (SAH). Since the convection mechanism in SAHs is weak, numerous methods have been suggested to address this problem and improve thermal efficiency. Perforations and cross-flow configuration generate high turbulency and, consequently, high convection rate resulted. Hence these methods have been applied to enhance thermal efficiency. To achieve this goal, an experimental setup was fabricated and tested at outdoor conditions for two air mass flow rates (mair) of 0.015 kg/s and 0.03 kg/s while several sensors monitored the collector’s heat dynamics and ambient conditions. The obtained results illustrate that outlet temperature reaches the peak values of 38 oC and 34 oC, which is only 6 oC and 7 oC lower than the maximum absorber temperature. This crucial issue proves a high heat exchange rate in the fabricated SAH that causes the absorber temperature to approach the outlet temperature due to high turbulency. The strong convection mechanism in the fabricated SAH improves daily thermal efficiency, in which its value reaches nearly 78.6% for the mass flow rate of 0.03 kg/s. In conclusion, the square cross-flow perforated SAH is an economy, applicable, compact collector, ensuring high thermal efficiency.
Energy
A. Amini; N. M. Nouri; S. Niazi; A. Abedi
Abstract
Surface-piercing propellers (SPP) are known as one of the most efficient propellers in marine sciences and maritime industries. In this study, different types of simulations were performed on an SPP in various rotational speeds in open water conditions, and a numerical study was also carried out on a ...
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Surface-piercing propellers (SPP) are known as one of the most efficient propellers in marine sciences and maritime industries. In this study, different types of simulations were performed on an SPP in various rotational speeds in open water conditions, and a numerical study was also carried out on a particular type of such propellers. In fact the main purpose of this paper is comparing the simulation results with the experimental results from past in order to derive a trustable soultion for future works. For this purpose, the surface-piercing propeller was simulated by OpenFoam software (an open source software with high range of capabilities) in order to analyze the results. The performance curve was then plotted and compared with the ones from open water tests. In this case the turbulance model of K-Epsilon RNG was used which is capable of increasing Y+ to 300 which is monitored at the end of the simulation with the maximum amount of 315 and the average of 80. Results showed that the curves followed the same pattern and trends in the numerical study, and the report pointed to similar findings. In conclusion, it was proved that the sliding mesh method was a proper way for simulating propellers, particularly SPPs. The curves for thrust and torque coefficients of the SPP were also compared with the literature and the efficiency curve was plotted.
Energy
H. Eskandari
Abstract
Increasing demand for agricultural products and production of resource constraints- especially the limitation of cultivable areas - have made the highest yield per unit area the main goal of agricultural producers. Agriculture is a system exhibiting high energy consumption and production. Since energy ...
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Increasing demand for agricultural products and production of resource constraints- especially the limitation of cultivable areas - have made the highest yield per unit area the main goal of agricultural producers. Agriculture is a system exhibiting high energy consumption and production. Since energy has a direct impact on the efficiency of crop production, a sustainable agricultural system needs to be analyzed in terms of its input and output energy to determine the total consumed energy of production per unit area. The difference between input and output energy determines energy efficiency of an agronomical system. Input energy requires being well analyzed to reduce energy consumption and increase energy efficiency. This paper reviews energy efficiency indices based on energy consumption during planting and harvesting. To enhance energy efficiency of agronomical systems, some strategies are discussed in detail, including using high quality seeds, minimum tillage systems, direct seeded rice, weeds control especially in irrigation canals and plant nutrition through agronomical management. Although some agronomical strategies -like complementary irrigation in dry land farming systems- increase input energy, they increase crop yield. However, when output energy, resulting from the rise in crop yield, is higher than input energy, the system energy efficiency improves. Still, some inputs cannot be altered according to regional conditions which are often related to harvest stages operations.
Energy
J. Ahmadi; S. M. Maddahi; R. Mirzaei
Abstract
All important decisions that affect the thermal performance of the building are made in the early stages of design. Accordingly, in this research, the initial stage of architectural design which is related to space plan was targeted. The aim of this research is the perfect approach to evaluate, and optimize ...
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All important decisions that affect the thermal performance of the building are made in the early stages of design. Accordingly, in this research, the initial stage of architectural design which is related to space plan was targeted. The aim of this research is the perfect approach to evaluate, and optimize the energy a set of alternative spatial layout solutions through the functional computational design model. The method of this research includes the production of coherent design solutions and the evaluation and optimization of the energy performance of the selected solutions. In the first part, space allocation at a level produces the plan through an evolutionary technique. In the next step, certain plans were evaluated for energy performance, performance rank, and optimization. The energy simulation tool is Honeybee and Ladybug plugins,. The optimization tool is Pareto Evolutionary Algorithm in the Octopus plugin. The reproduction rate, the mutation rate and the possibility of mutation were 0.9, 0.8 and 0.2, respectively. The results showed that each algorithm is a suitable tool for design solutions, thermal performance of floor plans, helping architects’ perspective in the decision-making process, and speeding up the design process. Finally, based on the optimization, the final result of the research algorithm is 70 elite answers in the Pareto front. Only during the Pareto front optimal responses, energy consumption can be reduced by more than 30%; in daylight time and more than 39% improvement was achieved.
Energy
F. Akhlaghinezhad; H. Bagheri Sabzevar
Abstract
Considering the global energy crisis and the need to reduce energy consumption while providing thermal comfort to occupants, building performance prediction using building simulation programs requires higher accuracy of output data. Therefore, it seems necessary to study the impact of occupant behavior, ...
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Considering the global energy crisis and the need to reduce energy consumption while providing thermal comfort to occupants, building performance prediction using building simulation programs requires higher accuracy of output data. Therefore, it seems necessary to study the impact of occupant behavior, which is the main source of uncertainty in residential buildings. The traditional courtyard houses, which are recognized as a successful passive house model, respond to different climatic conditions. Therefore, this research focuses on this building type to analyze occupant window opening control scenarios and determine which control works better. For this purpose, several probabilistic controls and their effects on the adaptive thermal comfort of occupants in zones around a central courtyard were compared in the three cities of Yazd, Bandar Abbas, and Tabriz. Energy Plus was used as a simulation program for the application of Grasshopper's energy management system (EMS) along with the Ladybug and Honeybee environmental plugins. The results show that the window control algorithms can increase the adaptive thermal comfort of occupants by 25.7%, 32.2%, and 20.3% in each of the climates of Yazd, Bandar Abbas, and Tabriz cities, respectively. Indoor and outdoor temperature were the most significant variables for opening windows in the warm and cold seasons, respectively.
Energy
A. Haghani; M. Jahangiri; R. Riahi; M. Golali Jonaghani; A. Baharizadeh
Abstract
The use of fossil fuels leads to greenhouse gas emissions, global warming, and secondary consequences such as desertification and winds in the Middle East and Africa, including Egypt. The use of renewable energy is the most appropriate solution to prevent the emission of polluting gases. Egypt is one ...
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The use of fossil fuels leads to greenhouse gas emissions, global warming, and secondary consequences such as desertification and winds in the Middle East and Africa, including Egypt. The use of renewable energy is the most appropriate solution to prevent the emission of polluting gases. Egypt is one of the best places to use solar water heating systems, located in the solar belt. In this paper, for the first time, the best place to use solar water heater (SWH) systems is examined using TSOL 2018 R(1) software and climate data for residential apartments in 35 stations in Egypt. The results showed that Sharm el sheikh station with supplies 96.8% of its total heat needs is the most suitable station for using solar water heating systems. According to the studies performed, using solar water heaters in the studied stations generated good energy savings annually (production of 134.5 GWh of solar heat). Also, greenhouse gas emissions were significantly reduced (preventing the emission of about 39.2 tons of CO2 pollutants per year) and as a result, the government should turn to the use of clean and renewable energy.
Energy
M. R. Hayati; S. Ranjbar; M. R. Abdar; M. Molaei Nasab; S. Homayounmajd; M. Esmaeili Shayan
Abstract
With countries throughout middle east and north Africa pursuing ambitious targets for a transition to renewable energies, the political economy of a region predominantly analyzed through the prism of fossil fuels is on the verge of radical change. As hydrocarbon prices decline, the low-cost producers ...
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With countries throughout middle east and north Africa pursuing ambitious targets for a transition to renewable energies, the political economy of a region predominantly analyzed through the prism of fossil fuels is on the verge of radical change. As hydrocarbon prices decline, the low-cost producers of Middle East have an advantage and should be the last to leave the market. The world will demand proportionally more of the region’s oil and gas. Nearly half of the world's oil is located in Middle East, which has long been referred to as the "energy axis" of the planet. In the meanwhile, as the nations of this area progress towards the future, they have realized the need of supplying energy from these other sources, such that the utilization of renewable energy sources, such as the sun, has attracted considerable interest. This study analyzed and assessed these attractions in addition to five middle eastern nations and Turkey, which is located in middle east, close proximity to this area. The approach of comparing government incentives in the development of renewable power plants was used in this study. The final findings revealed the current status of this energy in the target nations. This study may give the target countries and other nations in the middle east with a wealth of information for the formulation of effective policies for the use of renewable resources.
Energy
A. A. Sheikh Aleslami; H. Sadeghi
Abstract
Tall buildings are subject to wind loads as one of the effective lateral loads. An analysis of the effect of wind on Milad Tower is presented in this research. The wind tunnel testing results and numerical modelling implemented in computational fluid dynamics (CFD) using ANSYS software. For the numerical ...
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Tall buildings are subject to wind loads as one of the effective lateral loads. An analysis of the effect of wind on Milad Tower is presented in this research. The wind tunnel testing results and numerical modelling implemented in computational fluid dynamics (CFD) using ANSYS software. For the numerical simulation, the K-epsilon model has been used. The study evaluated the flow around the tower in several deformation states and compared it with a model where the tower is modeled rigidly in the wind tunnel. The maximum coefficient of negative pressure (suction) at the top of the tower structure equals to -1.95, which occurs at q =90o, and the maximum coefficient of the positive pressure equals +1. Since the buildings near the tower are located a short distance from the tower, the shed's structure, which is located near the tower, has also been investigated. With the aid of Tecplot software. The wind pressure coefficients obtained from the wind tunnel test were plotted. As part of the wind loading analysis in the single-span and two-span shed models, the model is rotated with a step of 5o relative to the direction of wind application, and wind pressure is recorded.
Energy
N. Deb; M. Z. Alam; T. Rahman; M. S. Jami; M. F. Bt. Mansor; H. B. A. Tajuddin
Abstract
The world's most economically developed countries are facing an energy crisis caused by geopolitical instability, rising energy costs, global stock disruptions, and a shift towards low-carbon energy sources that has yet to be fully realized. Electrification of the transportation industry offers the advantages ...
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The world's most economically developed countries are facing an energy crisis caused by geopolitical instability, rising energy costs, global stock disruptions, and a shift towards low-carbon energy sources that has yet to be fully realized. Electrification of the transportation industry offers the advantages of increased energy efficiency and reduced local pollutants. Electric Vehicles (EVs) are environmentally friendly because they reduce fossil fuels usage even zero consumption, need fewer maintenance requirements, and lower operating costs than the vehicles powered by gasoline or diesel. However, this study focuses on comparing various energy management strategies (EMS) for a backup energy supply system for EVs. The hybrid power system (HPS) considered in this study includes DC-DC and DC-AC synchronous converters, as well as supercapacitors, batteries, and fuel cells. The EMS analyzed includes state machine control, classical proportional-integral control, equivalent consumption minimization, frequency decoupling, rule-based fuzzy logic, and fuzzy logic control. The HPS's efficiency, hydrogen fuel, supercapacitor or battery state of charge levels, and overall performance are evaluated as primary efficiency criteria. Additionally, the HPS not only increases system energy but also reduces the number of pack batteries required. This study designs and constructs the combined power systems to enhance EV power schemes with rechargeable battery power supplies. The results show that a 6-kW fuel cell hybrid increases the power system capacity to 408 kWh. Moreover, a novel method based on wavelet transforms of the instantaneous power of each energy source is used to quantify the stressors on each energy source that impact its life cycle. To validate all analyses and performance, a simulation model and an experimental test bench are created. Finally, simulation results demonstrate a synchronous converter with a 6-kW output power and 96% efficiency, validating the optimization results.
Energy
H. Eskandari; S. N. Mosavian
Abstract
This research, conducted in Gotvand, southwest of Iran, compared the energy consumption of two cucumber production systems: field and greenhouse production systems. In this study, energy inputs of two production systems of cucumber (including seed, pesticide, human labor, machinery, diesel fuel, electricity, ...
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This research, conducted in Gotvand, southwest of Iran, compared the energy consumption of two cucumber production systems: field and greenhouse production systems. In this study, energy inputs of two production systems of cucumber (including seed, pesticide, human labor, machinery, diesel fuel, electricity, organic manure, chemical fertilizer) were determined from questionnaires completed by farmers. The results of the experiment indicated that the energy input of the two cultivation systems was not significantly different in input energies. In both cucumber production systems, the most input energy was allocated to nitrogen fertilizer (57% and 53% for field and greenhouse, respectively) followed by diesel fuel (21% in both production systems). Non-renewable energies accounted for 90 and 88% of the total energy input to the farm and greenhouse systems, respectively. Total output energy of field and greenhouse cucumber production system was 33000 and 34000 MJ, respectively. Reducing the consumption of nitrogen fertilizer through the use of appropriate crop rotation is a suitable solution to improve energy efficiency in the cucumber production system.
Energy
S. Naranjo-Silva; D. Punina-Guerrero; J. Barros-Enriquez; J. Almeida-Dominguez; J. Alvarez del Castillo
Abstract
The present manuscript aims to identify the advantages and consequences of hydropower development, showing a view of trends finding the status and situation in Brazil, Colombia, and Ecuador. This study uses a non-experimental methodology based on a comprehensive literature review of relevant papers retrieved ...
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The present manuscript aims to identify the advantages and consequences of hydropower development, showing a view of trends finding the status and situation in Brazil, Colombia, and Ecuador. This study uses a non-experimental methodology based on a comprehensive literature review of relevant papers retrieved from 41 selected papers that are summarized covering different application areas in these selected countries. In addition, the non-experimental methodology is guided by a perspective design sequential with a qualitative phase defining two indicators that do a relation between the people and the installed capacity in megawatts (MW) and energy production in gigawatts hour (GWh). The results show Colombia has the main installed capacity and energy generation per capita, followed by Ecuador, and finally, Brazil. According to the models and studies, the general hydropower potential of Brazil, Colombia, and Ecuador decreases as time goes on because this renewable energy affects the water quality, interacting deeply with the surrounding environment. However, in South American countries only 34% of hydropower potential has developed.
Energy
A. Kamyab; M. Mahmoodi Zarandi; M. Nikpour
Abstract
The city of Yazd has a large number of traditional houses. Houses with central courtyards and an Iwan were suitable for establishing thermal comfort conditions. In this research, the effect of Iwan's depth and the ratio of the adjacent room's openings on the comfort condition in the residential courtyard ...
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The city of Yazd has a large number of traditional houses. Houses with central courtyards and an Iwan were suitable for establishing thermal comfort conditions. In this research, the effect of Iwan's depth and the ratio of the adjacent room's openings on the comfort condition in the residential courtyard buildings in Yazd city were evaluated. The current research aims to provide an optimal model of the Iwan to increase sustainable development and use such models as the Iwan in contemporary housing in the hot and dry climate of Yazd. In order to investigate the effect of parameters, samples from the north-facing room and south-facing room in a central courtyard model with different proportions of the Iwan and different sizes of the window were simulated in Design Builder software. The results showed that the depth of Iwan and window to wall ratio's (WWR) of the adjacent room’s window significantly affects the comfort (according to cooling load, heating load, and energy consumption) in this room. The results obtained in this research will be a new window to recover the concepts of old patterns and help to solve climate problems.
Energy
A. Habibzadeh; M. Abbasalizadeh; I. Mirzaee; S. Jafarmadar; H. Shirvani
Abstract
In this study, renewable energy sources including a high-temperature solar parabolic trough collector and geothermal water integrated with a modified Kalina cycle, a combined ORC-EJR cycle, an electrolyzer, an RO desalination unit, and a domestic water heater. SiO2 and TiO2 nanoparticles dissolved in ...
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In this study, renewable energy sources including a high-temperature solar parabolic trough collector and geothermal water integrated with a modified Kalina cycle, a combined ORC-EJR cycle, an electrolyzer, an RO desalination unit, and a domestic water heater. SiO2 and TiO2 nanoparticles dissolved in Therminol VP1 are applied as the working fluid of the solar collector. A comparative analysis of introduced working fluids is performed from energy, exergy as well as cost analysis point of view to evaluate their efficiencies. Solar irradiation, ambient temperature, and collector inlet temperature were the parameters investigated to discover their effects on energy and exergy efficiency, solar collector outlet temperature, hydrogen production rate, and freshwater production rate. The highest generated outlet temperature of the solar collector outlet was 693.8 K obtained by Therminol VP1/SiO2 nanofluid. The maximum energy and exergy efficiencies of the proposed system were 36.69 % and 17.76 %, respectively. Moreover, it is found that by increasing the solar collector inlet temperature, the hydrogen production rate decreases while the water production rate increases.
Energy
M. Beykani; R. Shafaghat; A. Yousefi
Abstract
This paper investigates the effect of the immersion ratio parameter on the hydrodynamic performance of three surface-piercing propellers with diameters of 0.125, 0.132 and 0.140m at different advancing speeds. Experimental tests have been carried out in the free surface water tunnel of the Babol Noshirvani ...
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This paper investigates the effect of the immersion ratio parameter on the hydrodynamic performance of three surface-piercing propellers with diameters of 0.125, 0.132 and 0.140m at different advancing speeds. Experimental tests have been carried out in the free surface water tunnel of the Babol Noshirvani University of Technology. The results showed that the maximum thrust coefficient of three propellers occurs in the velocity range of 3-3.5 m/s. This interval represents the transition area of the three propellers. Also, the effect of the blockage ratio on the hydrodynamic coefficients of three propellers relative to the advance coefficient has been studied. By increasing the immersion depth raises the propeller's wet surface and increases the thrust and torque hydrodynamic coefficients. However, growing the propeller's diameter to 0.140m causes the effect of the blockage ratio parameter by increasing the immersion and the propeller's torque experiences a decreasing trend. Therefore, maximum propeller efficiency value with diameter 0.140m in immersion ratio 0.60 and 0.70, incresing 38% and 44%, respectively; relative to other proepllers. Also, the curve of the efficiency gradient of three propellers in the optimum immersion ratio of 0.40 compared to the advancing coefficient shows that the maximum efficiency gradient occurs in the range of 0.7 to 0.9.
Energy
H. Farzan; M. Mahmoudi; E. Hasan Zaim
Abstract
Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. ...
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Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. Two scenarios are considered to assess the dynamics and efficiency of this perforated SAH, including mair = 0.012 kg/s and 0.024 kg/s. Numerous sensors monitored the dynamics of the perforated SAH and ambient factors for 12 hours in October 2022. The experimental outcomes illustrate that the perforation method remarkably enhances the thermal efficiency of the perforated SAH compared with standard smooth SAHs. The daily thermal efficiency of the perforated SAH reaches 73.30% and 82.65%, while the outlet air temperature experiences peak values of 39 oC and 42 oC at noon and keeps within 90% of its maximum value for 2 hours for the scenarios considered. Improving the convection mechanism causes the flowing air to extract the absorber’s thermal energy more effectively. Hence the SAH can produce an airstream near its maximum temperature for an extended duration. In conclusion, the perforation method is a robust, simple method to boost the thermal efficiency of SAHs.
