Advanced Energy Technologies
Ala Moradi; Hajar Es-haghi; Seyed Hassan Hashemabadi; Majid Haghgoo; Zahra Emami
Abstract
Due to their high energy storage capacity, phase change materials (PCMs) have received significant attention as thermal energy storage systems. However, their low thermal conductivity reduces the rate of heat transfer. Incorporating nanoparticles into the matrix of PCM can be an efficient way to solve ...
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Due to their high energy storage capacity, phase change materials (PCMs) have received significant attention as thermal energy storage systems. However, their low thermal conductivity reduces the rate of heat transfer. Incorporating nanoparticles into the matrix of PCM can be an efficient way to solve their deficiency. In the current research, nano-enhanced phase change materials (NEPCM) based on Eicosane and incorporated nano graphite were prepared, and their thermal characteristics were evaluated. The SEM micrographs of graphite nano-powders, pure Eicosane, and prepared nanocomposites were analyzed. Differential scanning calorimetry (DSC) and thermal conductivity evaluation (TC) of samples were conducted to determine their heat capacity, thermal diffusivity, and thermal conductivity. The results illustrated that the more graphite nanoparticles, the more collision number between graphite and Eicosane. Therefore, nanocomposites' thermal conductivity and diffusivity are increased with nanophase. Furthermore, increasing crystal growth and reducing heat capacity for the high amount of nanoparticles in the composite were discussed.
Advanced Energy Technologies
Seyed Amir Hassan Bathaei; Masoud Iranmanesh; Hossein Amiri; Hajir Kourki
Abstract
Thermal Energy Storage (TES) for solar thermal systems has attracted great attention because of the intermittent availability of solar energy. In the current paper, new combinations of several Phase Change Materials (PCMs) including a type of paraffin and some mineral compounds like ammonium nitrate ...
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Thermal Energy Storage (TES) for solar thermal systems has attracted great attention because of the intermittent availability of solar energy. In the current paper, new combinations of several Phase Change Materials (PCMs) including a type of paraffin and some mineral compounds like ammonium nitrate and magnesium nitrate hexahydrate were exanimated and their thermo-physical properties were compared. This study targets solar heating systems at different temperature intervals for the TES. Another new approach of this study is to determine the effect of Multi-Wall Carbon Nanotubes (MWCNTs) with two diameters (D) of 8 and 10-20 nm on paraffin's thermophysical property to improve these properties. An innovative method was used to measure Electrical Conductivity (EC) as it is easier to measure than thermal conductivity (K) to study the effect of nanoparticles on PCM behavior. The results showed that the highest values of improvement over paraffin properties were related to 5% nanoparticle additive for both nanoparticle diameters among the percentages studied. The addition of 5 % nanoparticles with 10-20 nm and 8 nm to paraffin at 25 ° C increased heat conductivity by 142% and 156%, respectively. The addition of nanoparticles to paraffin improved EC several times such that a diameter of 8 nm made a 300% increase in EC compared to 10-20 nm.
Advanced Energy Technologies
Njovana G. Allen; Wenying Yu; Qiying Shen; Jiarui Li; Yanyan Zhu; Yongsheng Liu
Abstract
This study aims to assess the potential of coupling solar PV power plants with Battery Energy Storage System (BESS) to curtail load-shedding and provide a stable and reliable baseload power generation in Zimbabwe. Data from geographical surveys, power plant proposals, and investment information from ...
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This study aims to assess the potential of coupling solar PV power plants with Battery Energy Storage System (BESS) to curtail load-shedding and provide a stable and reliable baseload power generation in Zimbabwe. Data from geographical surveys, power plant proposals, and investment information from related sources were reviewed and applied accordingly. Areas considered to be of good potential to employ the use of BESS were identified considering such factors as feasibility of PV plants, proximity to transmission lines, the size of a town or neighborhood, and energy demands for BESS Return On Investment (ROI) calculations. Previous studies have proven that 10% of the suitable land for PV systems has the capability to generate thirty times the current power demand of the nation operating even with the least efficiency. In recent years, coupling renewable energy sources with a suitable energy storage system yielded improved performances, giving consumers a reliable, stable, and predictable grid. BESS technologies on the utility scale have improved in recent years, giving more options with improved safety, and decreasing the purchase costs, too.
Advanced Energy Technologies
Samira Jafari; Mehran Ameri Mahabadi
Abstract
As a result of growing energy demand, shortage of fossil fuel resources, climate change, and environmental protection, the need for renewable energy sources has been growing rapidly. However, there is an urgent need to cope with intermittency and fluctuation of renewable energies. Various energy storage ...
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As a result of growing energy demand, shortage of fossil fuel resources, climate change, and environmental protection, the need for renewable energy sources has been growing rapidly. However, there is an urgent need to cope with intermittency and fluctuation of renewable energies. Various energy storage systems are considered as appropriate solutions to the above-mentioned problem. In the present manuscript, a novel compressed carbon dioxide energy storage system was proposed. Furthermore, an extra thermal energy storage with Therminol VP-1 as a working fluid, coupled with Parabolic Trough Collector (PTC), was added to the system. This integration is conducive to rising the inlet temperature of turbines and reducing the work load that should be done by the compressors. In the present study, a method based on software product including Engineering Equation Solver (EES) for determining thermodynamic characters per component and System Advisor Model (SAM) was employed to model the solar field for a desired location. Energy and exergy analyses were conducted to evaluate the whole cycle performance during charging and discharging periods. In this study, the city of Kerman located in the south-eastern part of Iran, with Direct Normal Incidence (DNI) of 950 , was selected for the present modeling. The results of a random day (June 22/2019) at time 15:00 represented the exergy efficiency of 66.98 % and the round trip efficiency of 93.14 %. High exergy efficiency and round trip efficiency of this system make this idea applicable to enhancing the total performance of the entire system.
Advanced Energy Technologies
Ehsan Hasan Zaim; Hadi Farzan
Abstract
Utilizing thermal storage units such as Phase Change Materials (PCMs) is a suitable approach to improving Solar Air Heaters (SAHs). The present study tries to assess the effects of PCM mass values on the heat dynamics and thermal performance of SAHs. To this aim, an analytical thermodynamic model was ...
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Utilizing thermal storage units such as Phase Change Materials (PCMs) is a suitable approach to improving Solar Air Heaters (SAHs). The present study tries to assess the effects of PCM mass values on the heat dynamics and thermal performance of SAHs. To this aim, an analytical thermodynamic model was developed and validated by available experimental data. This model provides a robust numerical framework to model the phase change phenomenon and analyze the heat dynamics and thermal performance of SAH using various PCM masses. Four scenarios were considered using the developed analytical model including SAHs using 0, 30, 60, 90 kg PCM. The obtained results illustrated that the maximum outlet temperature was reduced, approximately near 20 %, by increasing the PCM mass between 0 and 90 kg; however, heating time was extended to periods when solar energy availability was inadequate. The thermal performance improved by nearly 14.5 % in the SAH using 90 kg PCM mass compared to the SAH without using PCM. The thermal performance of the SAH with 90 kg PCM was slightly higher than the SAH using 30 kg of PCM; hence, a significant portion of stored thermal energy was lost during nighttime through heat exchange with ambient surroundings. The obtained results also showed that despite available latent thermal energy, the outlet air temperature profiles for the SAHs using different PCM mass were close after sunset due to the low thermal conductivity of paraffin.
Advanced Energy Technologies
Ghazanfar Shahgholian
Abstract
Renewable energy provides twenty percent of electricity generation worldwide. Hydroelectric power is the cheapest way to generate electricity today. It is a renewable source of energy and provides almost one-fifth of electricity in the world. Also, it generates electricity using a renewable natural resource ...
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Renewable energy provides twenty percent of electricity generation worldwide. Hydroelectric power is the cheapest way to generate electricity today. It is a renewable source of energy and provides almost one-fifth of electricity in the world. Also, it generates electricity using a renewable natural resource and accounting for six percent of worldwide energy supply or about fifteen percent of the world’s electricity. Hydropower is produced in more than 150 countries. Hydropower plant producers provide energy due to moving or falling water. This paper presents and discusses studies on hydroelectric power plant fields, which have been carried out by different investigators. This work aims to study and provide an overview of hydroelectric power plants such as applications, control, operation, modeling and environmental impacts. Also, the hybrid power and efficiency of the hydroelectric power plants has been investigated. The applications of a flexible AC transmission system (FACTS) controller in the power system with the hydroelectric power plants are presented.
Advanced Energy Technologies
Nima Amani
Abstract
Must limited energy resources and the need for energy saving make the design of buildings more efficient in terms of energy consumption. For this reason, proper orientation of buildings, use of sunlight, natural ventilation, application of consumable materials are factors that help reduce heat and cooling ...
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Must limited energy resources and the need for energy saving make the design of buildings more efficient in terms of energy consumption. For this reason, proper orientation of buildings, use of sunlight, natural ventilation, application of consumable materials are factors that help reduce heat and cooling loads. The objective of this study is to evaluate the energy efficiency of residential buildings using natural energy and optimizing the choice of materials for heat and cold saving with the Ecotect simulation software. According to analysis and simulation, it was found that the optimum materials of the main building components in a mild climate zone of Rasht city include (a) the Brick Conc block Plaster for a wall with the total radiation incident of 340 W/m2 and a radiation absorption of 240 W/m2, (b) Double Glazed-Low E for windows with the total radiation incident of 340 W/m2 and a radiation absorption of 100 W/m2, (c) Foam Core Ply Wood for door with the total radiation incident of 340 W/m2 and a radiation absorption of 200 W/m2, (d) ConcSlab- OnGround for floor with the total radiation incident of 340 W/m2 and a radiation absorption of 220 W/m2, and (e) Conc Roof Asphalt for roof with the total radiation incident of 340 W/m2 and a radiation absorption of 300 W/m2. According to an hourly temperature analysis of all stories of the building on two hot and cold days of the year and as observed by the design and material selection requirements, the building will be conditioned in an almost thermal comfort zone (below 30 degrees) in the warm season.
Advanced Energy Technologies
Azin Hasanvand; Mehdi Pourabdoli; Ahmad Ghaderi Hamidi
Abstract
The effect of Al2O3 (1-10 wt %) and Y2O3 (1-10 wt %) additions on thermochemical heat storage properties of Co3O4/CoO system was investigated by thermogravimetry, XRD, and SEM analyses. Results showed that the addition of Al2O3 to Co3O4 at constant 8 h mechanical activation improved the redox cycle stability ...
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The effect of Al2O3 (1-10 wt %) and Y2O3 (1-10 wt %) additions on thermochemical heat storage properties of Co3O4/CoO system was investigated by thermogravimetry, XRD, and SEM analyses. Results showed that the addition of Al2O3 to Co3O4 at constant 8 h mechanical activation improved the redox cycle stability and increased oxygen sorption value and rate. It was found that oxygen sorption and their rate decreased with increasing the alumina content to more than 8 wt %. The formation of the spinel phase and an increase in its amount by increasing the alumina content led to a decrease in the oxygen sorption capacity. SEM studies showed that Al2O3 prevented the sintering and particle growth of cobalt oxide particles during reduction and re-oxidation processes. In addition, results showed that the addition of Y2O3 in all ranges to Co3O4 improved the redox cycle stability of cobalt oxide; however, it significantly decreased the oxygen sorption in the Co3O4/CoO system. XRD patterns of a sample containing 10 wt % yttria before the redox process indicated the presence of only Co3O4 phase; however, after three redox cycles, other phases including CoO and Y2O3 appeared.
Advanced Energy Technologies
Mohammad Sajjad Rostami; Morteza Khashehchi; Payam Zarafshan; Mohammad Hossein Kianmehr; Ehsan Pipelzadeh
Abstract
Capacitive deionization (CDI) is an emerging energy efficient, low-pressure and low-cost intensive desalination process that has recently attracted experts’ attention. The process is to explain that ions (cations and anions) can be separated by a pure electrostatic force imposed by a small bias ...
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Capacitive deionization (CDI) is an emerging energy efficient, low-pressure and low-cost intensive desalination process that has recently attracted experts’ attention. The process is to explain that ions (cations and anions) can be separated by a pure electrostatic force imposed by a small bias potential. Even at a rather low voltage of 1.2 V, desalinated water can be produced. The process can be well operational by a professional cell design. Although various processes have been manufactured before, in this study, membrane was removed and a new unit was designed and manufactured (Using CFD Simulation). In this case, the combination of activated carbon powder (with an effective surface area of 2600 m2 per gram), carbon black, and polyvinyl alcohol with a ratio of 35/35/30 coated on carbon paper as electrode materials was considered for tests. The weight was 1.41 grams for each material, and the thickness was 0.44 mm. CDI system was tested, and the results of charge-discharge cycles, cyclic voltammetry, and impedance spectroscopy were evaluated. It can be implied that there is no need for a strong pump and, also, pressure drop can be reduced due to such a noticeable space between two electrodes. Preliminary experimental results showed high specific capacitance (2.1 Farad) and ultra-high salt adsorption capacity, compared with similar cases.
Advanced Energy Technologies
Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Mohsen Babaiee; Rahim Eqra
Abstract
In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. ...
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In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. Herein, to investigate the binding performance between MCMB artificial graphite and the copper current collector, three binders such as PVDF, MSBR, and CMC+SBR were used to prepare the anode electrodes. The mechanical and electrochemical tests were conducted for different MCMB electrodes. The results show that the water-based binders (CMC+SBR and MSBR) made better adhesion properties for the coating on the current collector in comparison with the organic solvent-based binder (PVDF). MCMB anode fabricated with CMC+SBR binder shows the highest discharge capacity and the best rate performance at various C-rates of 0.2C, 0.5C, and 1C that result in the brilliant electrochemical performance. Therefore, artificial graphite anode materials using cheap aqueous CMC+SBR binder instead of toxic solvent like NMP and expensive PVDF improve electrochemical property and reduce the cost of LIBs.
Advanced Energy Technologies
Mohammad Jafari; Hossein Ghadamian; Leila Seidabadi
Abstract
The study of the battery charge process as the only power storage agent in off-grid systems is of significant importance. The battery charge process has different modes, and the battery in these modes is dependent on the amount of charge. In order to charge the battery in off-grid systems, two charge ...
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The study of the battery charge process as the only power storage agent in off-grid systems is of significant importance. The battery charge process has different modes, and the battery in these modes is dependent on the amount of charge. In order to charge the battery in off-grid systems, two charge controllers including Pulse Width Modulation (PWM) and Maximum Power Point Tracker (MPPT) are commonly used. The charge rate (C-Rate) is different in these two models. Therefore, it is necessary to study the state of charge (SoC) in the PWM and MPPT models considerably. In this study, by using these two charge controller models, C-Rate is examined on portable and power plant scales. This research indicates that the PWM charge controller has better performance on the power plant scale than on the portable scale. The charging quality of the MPPT model is about 31 % and 7 % on portable and power plant scales, respectively, proved to be higher than that of the PWM charge controller. The PV panel performance has increased by 2 %-5 % through the application of the MPPT charge controller, compared with the PWM model. As the overall achievement of the experiment, according to the limitations of the MPPT charge controller, the PWM charge controller can be proposed on power plant scales, whereas the application of the MPPT model is appropriate for specific purposes.
