Search results for: photovoltaic solar energy

Authors: Daniel Manaye Kabtamu, Anteneh Wodaje Bayeh

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With the development and utilization of new energy technology, people’s demand for large-scale energy storage system has become increasingly urgent. Vanadium redox flow battery (VRFB) is one of the most promising technologies for grid-scale energy storage applications because of numerous attractive features, such as long cycle life, high safety, and flexible design. However, the relatively low energy efficiency and high production cost of the VRFB still limit its practical implementations. It is of great attention to enhance its energy efficiency and reduce its cost. One of the main components of VRFB that can impressively impact the efficiency and final cost is the electrode materials, which provide the reactions sites for redox couples (V₂₊/V³⁺ and VO²⁺/VO₂⁺). Graphite felt (GF) is a typical carbon-based material commonly employed as electrode for VRFB due to low-cost, good chemical and mechanical stability. However, pristine GF exhibits insufficient wettability, low specific surface area, and poor kinetics reversibility, leading to low energy efficiency of the battery. Therefore, it is crucial to further modify the GF electrode to improve its electrochemical performance towards VRFB by employing active electrocatalysts, such as less expensive metal oxides. This study successfully fabricates low-cost plate-like bismuth vanadate (BiVO₄) material through a simple one-step hydrothermal route, employed as an electrocatalyst to adorn the GF for use as the negative electrode in VRFB. The experimental results show that BiVO₄-3h exhibits the optimal electrocatalytic activity and reversibility for the vanadium redox couples among all samples. The energy efficiency of the VRFB cell assembled with BiVO₄-decorated GF as the negative electrode is found to be 75.42% at 100 mA cm−2, which is about 10.24% more efficient than that of the cell assembled with heat-treated graphite felt (HT-GF) electrode. The possible reasons for the activity enhancement can be ascribed to the existence of oxygen vacancies in the BiVO₄ lattice structure and the relatively high surface area of BiVO₄, which provide more active sites for facilitating the vanadium redox reactions. Furthermore, the BiVO₄-GF electrode obstructs the competitive irreversible hydrogen evolution reaction on the negative side of the cell, and it also has better wettability. Impressively, BiVO₄-GF as the negative electrode shows good stability over 100 cycles. Thus, BiVO₄-GF is a promising negative electrode candidate for practical VRFB applications.

Keywords: BiVO₄ electrocatalyst, electrochemical energy storage, graphite felt, vanadium redox flow battery

Procedia PDF Downloads 1555

Authors: Iñaki Milton-Laskibar, Leixuri Aguirre, Maria P. Portillo

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Introduction: Energy restriction is an effective approach in preventing liver steatosis. However, due to social and economic reasons among others, compliance with this treatment protocol is often very poor, especially in the long term. Resveratrol, a natural polyphenolic compound that belongs to stilbene group, has been widely reported to imitate the effects of energy restriction. Objective: To analyze the effects of resveratrol under normoenergetic feeding conditions and under a mild energy restriction on liver fat accumulation and hepatic fatty acid oxidation. Methods: 36 male six-week-old rats were fed a high-fat high-sucrose diet for 6 weeks in order to induce steatosis. Then, rats were divided into four groups and fed a standard diet for 6 additional weeks: control group (C), resveratrol group (RSV, resveratrol 30 mg/kg/d), restricted group (R, 15 % energy restriction) and combined group (RR, 15 % energy restriction and resveratrol 30 mg/kg/d). Liver triacylglycerols (TG) and total cholesterol contents were measured by using commercial kits. Carnitine palmitoyl transferase 1a (CPT 1a) and citrate synthase (CS) activities were measured spectrophotometrically. TFAM (mitochondrial transcription factor A) and peroxisome proliferator-activator receptor alpha (PPARα) protein contents, as well as the ratio acetylated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α)/Total PGC1α were analyzed by Western blot. Statistical analysis was performed by using one way ANOVA and Newman-Keuls as post-hoc test. Results: No differences were observed among the four groups regarding liver weight and cholesterol content, but the three treated groups showed reduced TG when compared to the control group, being the restricted groups the ones showing the lowest values (with no differences between them). Higher CPT 1a and CS activities were observed in the groups supplemented with resveratrol (RSV and RR), with no difference between them. The acetylated PGC1α /total PGC1α ratio was lower in the treated groups (RSV, R and RR) than in the control group, with no differences among them. As far as TFAM protein expression is concerned, only the RR group reached a higher value. Finally, no changes were observed in PPARα protein expression. Conclusions: Resveratrol administration is an effective intervention for liver triacylglycerol content reduction, but a mild energy restriction is even more effective. The mechanisms of action of these two strategies are different. Thus resveratrol, but not energy restriction, seems to act by increasing fatty acid oxidation, although mitochondriogenesis seems not to be induced. When both treatments (resveratrol administration and a mild energy restriction) were combined, no additive or synergic effects were appreciated. Acknowledgements: MINECO-FEDER (AGL2015-65719-R), Basque Government (IT-572-13), University of the Basque Country (ELDUNANOTEK UFI11/32), Institut of Health Carlos III (CIBERobn). Iñaki Milton is a fellowship from the Basque Government.

Keywords: energy restriction, fat, liver, oxidation, resveratrol

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Authors: Ankitsinh Chauhan, Vimal Patel, A. D. Parekh, Ishant patil

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This study delves into the crucial influence of cooling tower fan operation on the performance of a chiller plant, with a specific focus on the Chiller Plant at SVNIT. Continuous operation of the chiller plant led to unexpected damage to the cooling tower's belt drive, rendering the cooling tower fan non-operational. Consequently, the efficiency of heat transfer in the condenser was significantly impaired. In response, we analyzed and calculated several vital parameters, including the Coefficient of Performance (COP), heat rejection in the condenser (Qc), work required for the compressor (Wc), and heat absorbed by the refrigerant in the evaporator (Qe). Our findings revealed that in the absence of the cooling tower fan, relying solely on natural convection, the COP of the chiller plant reached a minimum value of 5.49. However, after implementing a belt drive to facilitate forced convection for the cooling tower fan, the COP of the chiller plant experienced a noteworthy improvement, reaching approximately 6.27. Additionally, the utilization of forced convection resulted in an impressive reduction of 8.9% in compressor work, signifying enhanced energy efficiency. This study underscores the critical role of cooling tower fan operation in optimizing chiller plant performance, with practical implications for energy-efficient HVAC systems. It highlights the potential benefits of employing forced convection mechanisms, such as belt drives, to ensure efficient heat transfer in the condenser, ultimately contributing to improved energy utilization and reduced operational costs in cooling.

Keywords: cooling tower, chiller Plant, cooling tower fan, energy efficiency, VCRS.

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Authors: Dmytro Symak

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Drying is a complex technologic, thermal and energy process. Energy cost of drying processes in many cases is the most costly stage of production, and can be over 50% of total costs. As we know, in Ukraine over 85% of Portland cement is produced moist, and the finished product energy costs make up to almost 60%. During the wet cement production, energy costs make up over 5500 kJ / kg of clinker, while during the dry only 3100 kJ / kg, that is, switching to a dry Portland cement will allow result into double cutting energy costs. Therefore, to study raw materials drying process in the manufacture of Portland cement is very actual task. The fine ferrous materials drying (small pyrites, red mud, clay Kyoko) is recommended to do by filtration method, that is one of the most intense. The essence of filtration method drying lies in heat agent filtering through a stationary layer of wet material, which is located on the perforated partition, in the "layer-dispersed material - perforated partition." For the optimum drying purposes, it is necessary to establish the dependence of pressure loss in the layer of dispersed material, and the values of heat and mass transfer, depending on the speed of the gas flow filtering. In our research, the experimentally determined pressure loss in the layer of dispersed material was generalized based on dimensionless complexes in the form and coefficients of heat exchange. We also determined the relation between the coefficients of mass and heat transfer. As a result of theoretic and experimental investigations, it was possible to develop a methodology for calculating the optimal parameters for the thermal agent and the main parameters for the filtration drying installation. The comparison of calculated by known operating expenses methods for the process of small pyrites drying in a rotating drum and filtration method shows to save up to 618 kWh per 1,000 kg of dry material and 700 kWh during filtration drying clay.

Keywords: drying, cement, heat and mass transfer, filtration method

Procedia PDF Downloads 247

Authors: Julie Connelly, Tanvi Toprani, Xin Xie, Dhinoth Kumar Bangarusamy, Kris C. Gunsalus

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The overuse of antibiotics worldwide has contributed to the development of multi-drug resistant (MDR) pathogenic bacterial strains. There is an increasing urgency to discover antibiotics to combat MDR pathogens. The microbiome of the Arabian Gulf is a largely unexplored and potentially rich source of novel bioactive compounds. Microbes that inhabit the Abu Dhabi coastal regions adapt to extreme environments with high salinity, hot temperatures, large temperature fluctuations, and acute exposure to solar energy. The microbes native to this region may produce unique metabolites with therapeutic potential as antibiotics and antifungals. We have isolated 200 pure bacterial strains from mangrove sediments, cyanobacterial mats, and coral reefs of the Abu Dhabi region. In this project, we aim to screen the marine bacterial strains to identify antibiotics, in particular undocumented compounds that show activity against existing antibiotic-resistant strains. We have acquired the ESKAPE pathogen panel, which consists of six antibiotic-resistant gram-positive and gram-negative bacterial pathogens that collectively cause most clinical infections. Our initial efforts of the primary screen using colony-picking co-culture assay have identified several candidate marine strains producing potential antibiotic compounds. We will next apply different assays, including disk-diffusion and broth turbidity growth assay, to confirm the results. This will be followed by bioactivity-guided purification and characterization of target compounds from the scaled-up volume of candidate strains, including SPE fraction, HPLC fraction, LC-MS, and NMR. For antimicrobial compounds with unknown structures, our final goal is to investigate their mode of action by identifying the molecular target.

Keywords: marine bacteria, natural products, drug discovery, ESKAPE panel

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Authors: Asmir Gogic, Aljo Mujcic, Sandra Ibric, Nermin Suljanovic

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Ubiquity of natural disasters during last few decades have risen serious questions towards the prediction of such events and human safety. Every disaster regardless its proportion has a precursor which is manifested as a disruption of some environmental parameter such as temperature, humidity, pressure, vibrations and etc. In order to anticipate and monitor those changes, in this paper we propose an overall system for disaster prediction and monitoring, based on wireless sensor network (WSN). Furthermore, we introduce a modified and simplified WSN routing protocol built on the top of the trickle routing algorithm. Routing algorithm was deployed using the bluetooth low energy protocol in order to achieve low power consumption. Performance of the WSN network was analyzed using a real life system implementation. Estimates of the WSN parameters such as battery life time, network size and packet delay are determined. Based on the performance of the WSN network, proposed system can be utilized for disaster monitoring and prediction due to its low power profile and mesh routing feature.

Keywords: bluetooth low energy, disaster prediction, mesh routing protocols, wireless sensor networks

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Authors: Masood Roohi, Amir Taghavipour

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This paper describes a strategy to develop an energy management system (EMS) for a charge-sustaining power-split hybrid electric vehicle. This kind of hybrid electric vehicles (HEVs) benefit from the advantages of both parallel and series architecture. However, it gets relatively more complicated to manage power flow between the battery and the engine optimally. The applied strategy in this paper is based on nonlinear model predictive control approach. First of all, an appropriate control-oriented model which was accurate enough and simple was derived. Towards utilization of this controller in real-time, the problem was solved off-line for a vast area of reference signals and initial conditions and stored the computed manipulated variables inside look-up tables. Look-up tables take a little amount of memory. Also, the computational load dramatically decreased, because to find required manipulated variables the controller just needed a simple interpolation between tables.

Keywords: hybrid electric vehicles, energy management system, nonlinear model predictive control, real-time

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Authors: María Canal-Rodríguez, María Arnaiz, Natalia Rey-Raap, Ana Arenillas, Jon Ajuria

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The constant demand of electrical energy, as well as the increase in environmental concern, lead to the necessity of investing in clean and eco-friendly energy sources that implies the development of enhanced energy storage devices. Li-ion batteries (LIBs) and Electrical double layer capacitors (EDLCs) are the most widespread energy systems. Batteries are able to storage high energy densities contrary to capacitors, which main strength is the high-power density supply and the long cycle life. The combination of both technologies gave rise to Li-ion capacitors (LICs), which offers all these advantages in a single device. This is achieved combining a capacitive, supercapacitor-like positive electrode with a faradaic, battery-like negative electrode. Due to the abundance and affordability, dual carbon-based LICs are nowadays the common technology. Normally, an Active Carbon (AC) is used as the EDLC like electrode, while graphite is the material commonly employed as anode. LICs are potential systems to be used in applications in which high energy and power densities are required, such us kinetic energy recovery systems. Although these devices are already in the market, some drawbacks like the limited power delivered by graphite or the energy limiting nature of AC must be solved to trigger their used. Focusing on the anode, one possibility could be to replace graphite with Hard Carbon (HC). The better rate capability of the latter increases the power performance of the device. Moreover, the disordered carbonaceous structure of HCs enables storage twice the theoretical capacity of graphite. With respect to the cathode, the ACs are characterized for their high volume of micropores, in which the charge is storage. Nevertheless, they normally do not show mesoporous, which are really important mainly at high C-rates as they act as transport channels for the ions to reach the micropores. Usually, the porosity of ACs cannot be tailored, as it strongly depends on the precursor employed to get the final carbon. Moreover, they are not characterized for having a high electrical conductivity, which is an important characteristic to get a good performance in energy storage applications. A possible candidate to substitute ACs are carbon aerogels (CAs). CAs are materials that combine a high porosity with great electrical conductivity, opposite characteristics in carbon materials. Furthermore, its porous properties can be tailored quite accurately according to with the requirements of the application. In the present study, CAs with controlled porosity were obtained from polymerization of resorcinol and formaldehyde by microwave heating. Varying the synthesis conditions, mainly the amount of precursors and pH of the precursor solution, carbons with different textural properties were obtained. The way the porous characteristics affect the performance of the cathode was studied by means of a half-cell configuration. The material with the best performance was evaluated as cathode in a LIC versus a hard carbon as anode. An analogous full LIC made by a high microporous commercial cathode was also assembled for comparison purposes.

Keywords: li-ion capacitors, energy storage, tailored porosity, carbon aerogels

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Authors: Alessandro Balbo, Gianvito Colucci, Matteo Nicoli, Laura Savoldi

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Hydrogen is expected to become a game changer in the energy transition, especially enabling sector coupling possibilities and the decarbonization of hard-to-abate end-uses. The Italian National Recovery and Resilience Plan identifies hydrogen as one of the key elements of the ecologic transition to meet international decarbonization objectives, also including it in several pilot projects for the early development in Italy. This matches the European energy strategy, which aims to make hydrogen a leading energy carrier of the future, setting ambitious goals to be accomplished by 2030. The huge efforts needed to achieve the announced targets require to carefully investigate of their feasibility in terms of economic expenditures and technical aspects. In order to quantitatively assess the hydrogen potential within the Italian context and the feasibility of the planned investments and projects, this work uses the TEMOA-Italy energy system model to study pathways to meet the strict objectives above cited. The possible hydrogen development has been studied both in the supply-side and demand-side of the energy system, also including storage options and distribution chains. The assessment comprehends alternative hydrogen production technologies involved in a competition market, reflecting the several possible investments declined by the Italian National Recovery and Resilience Plan to boost the development and spread of this infrastructure, including the sector coupling potential with natural gas through the currently existing infrastructure and CO2 capture for the production of synfuels. On the other hand, the hydrogen end-uses phase covers a wide range of consumption alternatives, from fuel-cell vehicles, for which both road and non-road transport categories are considered, to steel, and chemical industries uses and cogeneration for residential and commercial buildings. The model includes both high and low TRL technologies in order to provide a consistent outcome for the future decades as it does for the present day, and since it is developed through the use of an open-source code instance and database, transparency and accessibility are fully granted.

Keywords: decarbonization, energy system optimization models, hydrogen, open-source modeling, TEMOA

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Authors: Glaoui Hachemi

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Wind has been proven as a cost effective and reliable energy source. Technological advancements over the last years have placed wind energy in a firm position to compete with conventional power generation technologies. Algeria has a vast uninhabited land area where the south (desert) represents the greatest part with considerable wind regime. In this paper, an analysis of wind energy utilization as a viable energy substitute in six selected sites widely distributed all over the south of Algeria is presented. In this presentation, wind speed frequency distributions data obtained from the Algerian Meteorological Office are used to calculate the average wind speed and the available wind power. The annual energy produced by the Fuhrlander FL 30 wind machine is obtained using two methods. The analysis shows that in the southern Algeria, at 10 m height, the available wind power was found to vary between 160 and 280 W/m2, except for Tamanrasset. The highest potential wind power was found at Adrar, with 88 % of the time the wind speed is above 3 m/s. Besides, it is found that the annual wind energy generated by that machine lie between 33 and 61 MWh, except for Tamanrasset, with only 17 MWh. Since the wind turbines are usually installed at a height greater than 10 m, an increased output of wind energy can be expected. However, the wind resource appears to be suitable for power production on the south and it could provide a viable substitute to diesel oil for irrigation pumps and electricity generation. In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms, and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper, we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.

Keywords: windgenerator systems, permanent magnet synchronous generator (PMSG), wind turbine (WT) modeling, MATLAB simulink environment

Procedia PDF Downloads 323

Authors: O. Adjroud

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The present study was conducted to investigate the interaction between selenium (Se) and chloride nickel (NiCl2) on energy profiles in Wistar albino preimplanted rats. NiCl2 was given on day 3 of pregnancy either in distilled drinking water at a dose of 20 mg/L/day for 16 consecutive days or as a single subcutaneous (s.c.) dose of 25, 50, or 100 mg/kg. Se was given as a s.c. injection (0.3 mg/kg) together with the higher dose (100 mg/kg) of NiCl2. Changes in energy profiles were evaluated in treated and control groups on days 5 and 20 of gestation. NiCl2 s.c. induced a significant increase in plasma glucose on day 20 of pregnancy. NiCl2 s.c. induced on day 5 and 20 of gestation a significant decrease in plasma triglycerides, with the higher dose. This decrease was maintained at day 20 of gestation with doses of 50 mg /kg. In addition, NiCl2 s.c. caused on day 5 of gestation a significant decrease in plasma total cholesterol with the low and medium doses. The pretreatment with Se reversed the effects of NiCl2 on plasma glucose, total cholesterol and triglycerides levels. NiCl2 administered in the drinking water augmented significantly the plasma triglycerides and total cholesterol levels and slighty the plasma glucose on day 20 of gestation, while on day 5 of gestation NiCl2 s.c. Induced a significant decrease in cholesterol. Three doses of NiCl2 (sc) induced severe alterations in liver and architecture which are markedly improved by Selenium. These results suggested that selenium has protective effects on energy profiles against the toxicity induced by NiCl2 administered subcutaneously in preimplanted rats.

Keywords: hepatotoxicity, nickel chloride, preimplanted rat, biochemical parameters

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Authors: Mahadehe Hassan

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Transport system and industries which are the main basis of industrial and socio-economic development of any country. It is mainly dependent on fossil fuels. Bangladesh has fossil fuel reserves of 9.51 TCF as of July 2023, and if no new gas fields are discovered in the next 7-9 years and if the existing gas consumption rate continues, the fossil fuel reserves will be exhausted. The demand for petroleum products in Bangladesh is increasing steadily, with 63% imported by BPC and 37% imported by private companies. 61.61% of BPC imported products are used in the transport sector and 5.49% in the industrial sector, which is expensive and harmful to the environment. Liquefied Petroleum Gas (LPG) should be considered as an alternative energy for Bangladesh based on Sustainable Development Goals (SDGs) criteria for sustainable, clean and affordable energy. This will not only lead to the much desired mitigation of energy famine in the country but also contribute favorably to the macroeconomic indicators. Considering the environmental and economic issues, the government has referred to CNG (compressed natural gas) as the fuel carrier since 2000, but currently due to the decline mode of gas reserves, the government of Bangladesh is thinking of new energy sources for transport and industrial sectors which will be sustainable, environmentally friendly and economically viable. Liquefied Petroleum Gas (LPG) is the best choice for fueling transport and industrial sectors in Bangladesh. At present, a total of 1.54 million metric tons of liquefied petroleum gas (LPG) is marketed in Bangladesh by the public and private sectors. 83% of it is used by households, 12% by industry and commerce and 5% by transportation. Industrial and transport sector consumption is negligible compared to household consumption. So the purpose of the research is to find out the challenges of LPG market development in transport and industrial sectors in Bangladesh and make recommendations to reduce the challenges. Secure supply chain, inadequate infrastructure, insufficient investment, lack of government monitoring and consumer awareness in the transport sector and industrial sector are major challenges for LPG market development in Bangladesh. Bangladesh government as well as private owners should come forward in the development of liquefied petroleum gas (LPG) industry to reduce the challenges of secure energy sector for sustainable development. Furthermore, ensuring adequate Liquefied Petroleum Gas (LPG) supply in Bangladesh requires government regulations, infrastructure improvements in port areas, awareness raising and most importantly proper pricing of Liquefied Petroleum Gas (LPG) to address the energy crisis in Bangladesh.

Keywords: transportand industries fuel, LPG consumption, challenges, economical sustainability

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Authors: Tsegahun Milkesa

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This study investigates the implementation of Power-Line Communications (PLC) as a sustainable solution for home automation in Ethiopia. With the country's growing technological landscape and the quest for efficient energy use, this research explores the potential of PLC to facilitate smart home systems, aiming to enhance connectivity and energy management. The primary objective is to assess the feasibility and effectiveness of PLC in Ethiopian residences, considering factors such as infrastructure compatibility, reliability, and scalability. By analyzing existing PLC technologies and their adaptability to local contexts, this study aims to propose optimized solutions tailored to the Ethiopian environment. The research methodology involves a combination of literature review, field surveys, and experimental setups to evaluate PLC's performance in transmitting data and controlling various home appliances. Additionally, socioeconomic implications, including affordability and accessibility, are examined to ensure the technology's inclusivity in diverse Ethiopian households. The findings will contribute insights into the viability of PLC for sustainable connectivity in Ethiopian homes, shedding light on its potential to revolutionize energy-efficient and interconnected living spaces. Ultimately, this study seeks to pave the way for accessible and eco-friendly smart home solutions in Ethiopia, aligning with the nation's aspirations for technological advancement and sustainability.

Keywords: sustainable connectivity, power-line communications (PLC), home automation, Ethiopia, smart homes, energy efficiency, connectivity solutions, infrastructure development, sustainable living

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Authors: Svetlana Pushkar

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The Leadership in Energy and Environmental Design (LEED) green building rating system is recognized in Europe. LEED uses regional priority (RP) points that are adapted to different environmental conditions. However, the appropriateness of the RP points is still a controversial question. To clarify this issue, two different parts of Europe: northern Europe (Finland and Sweden) and southern Europe (Turkey and Spain) were considered. Similarities and differences in the performances of LEED 2009-new construction (LEED-NC 2009) in these four countries were analyzed. It was found that LEED-NC 2009 performances in northern and southern parts of Europe in terms of Sustainable Sites (SS), Water Efficiency (WE), Materials and Resources (MR), and Indoor Environmental Quality (EQ) were similar, whereas in Energy and Atmosphere (EA), their performances were different. WE and SS revealed high performances (70-100%); EA and EQ demonstrated intermediate performance (40-60%); and MR displayed low performance (20-40%). It should be recommended introducing the following new RP points: for Turkey - water-related points and for all four observed countries - green power-related points for improving the LEED adaptation in Europe.

Keywords: green building, Europe, LEED, leadership in energy and environmental design, regional priority points

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Authors: Francis C. Emejeamara, Alison S. Tomlin, James Gooding

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Due to the highly turbulent nature of urban air flows, and by virtue of the fact that turbines are likely to be located within the roughness sublayer of the urban boundary layer, proposed urban wind installations are faced with major challenges compared to rural installations. The challenge of operating within turbulent winds can however, be counteracted by the development of suitable gust tracking solutions. In order to assess the cost effectiveness of such controls, a detailed understanding of the urban wind resource, including its turbulent characteristics, is required. Estimating the ambient turbulence and total kinetic energy available at different control response times is essential in evaluating the potential performance of wind systems within the urban environment should effective control solutions be employed. However, high resolution wind measurements within the urban roughness sub-layer are uncommon, and detailed CFD modelling approaches are too computationally expensive to apply routinely on a city wide scale. This paper therefore presents an alternative semi-empirical methodology for estimating the excess energy content (EEC) present in the complex and gusty urban wind. An analytical methodology for predicting the total wind energy available at a potential turbine site is proposed by assessing the relationship between turbulence intensities and EEC, for different control response times. The semi-empirical model is then incorporated with an analytical methodology that was initially developed to predict mean wind speeds at various heights within the built environment based on detailed mapping of its aerodynamic characteristics. Based on the current methodology, additional estimates of turbulence intensities and EEC allow a more complete assessment of the available wind resource. The methodology is applied to 4 UK cities with results showing the potential of mapping turbulence intensities and the total wind energy available at different heights within each city. Considering the effect of ambient turbulence and choice of wind system, the wind resource over neighbourhood regions (of 250 m uniform resolution) and building rooftops within the 4 cities were assessed with results highlighting the promise of mapping potential turbine sites within each city.

Keywords: excess energy content, small-scale wind, turbulence intensity, urban wind energy, wind resource assessment

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Authors: T. Y. Liu, C. H. Lin, Y. M. Ferng

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Wind energy is one of the clean renewable energy. However, the low frequency (20-200HZ) noise generated from the wind turbine blades, which bothers the residents, becomes the major problem to be developed. It is useful for predicting the aerodynamic noise by flow field and pressure distribution analysis on the wind turbine blades. Therefore, the main objective of this study is to use different turbulence models to analyse the flow field and pressure distributions of the wing blades. Three-dimensional Computation Fluid Dynamics (CFD) simulation of the flow field was used to calculate the flow phenomena for the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor. Two different flow cases with different wind speeds were investigated: 7m/s with 72rpm and 15m/s with 72rpm. Four kinds of RANS-based turbulence models, Standard k-ε, Realizable k-ε, SST k-ω, and v2f, were used to predict and analyse the results in the present work. The results show that the predictions on pressure distributions with SST k-ω and v2f turbulence models have good agreements with experimental data.

Keywords: horizontal axis wind turbine, turbulence model, noise, fluid dynamics

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Authors: Muciz Özcan, Mustafa Sacid Endiz, Veysel Alver

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In this paper we present a new approach to the boom welding related to the mobile cranes manufacturing, implementing a new method in order to get homogeneous welding quality and reduced energy usage during booms production. We aim to get the realization of the same welding quality carried out on the boom in every region during the manufacturing process and to detect the possible welding errors whether they could be eliminated using laser sensors. We determine the position of the welding region directly through our system and with the help of the welding oscillator we are able to perform a proper boom welding. Errors that may occur in the welding process can be observed by monitoring and eliminated by means of an operator. The major modification in the production of the crane booms will be their form of the booms. Although conventionally, more than one welding is required to perform this process, with the suggested concept, only one particular welding is sufficient, which will be more energy and environment-friendly. Consequently, as only one welding is needed for the manufacturing of the boom, the particular welding quality becomes more essential. As a way to satisfy the welding quality, a welding manipulator was made and fabricated. By using this welding manipulator, the risks of involving dangerous gases formed during the welding process for the operator and the surroundings are diminished as much as possible.

Keywords: boom welding, seam tracking, energy saving, global warming

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Authors: A. Escoffier, A. Albrecht, F. Consigny

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In order to host the Football Euro in 2016, many French cities have launched architectural competitions in recent years to improve the quality of their stadiums. The winning project in Nice was designed by Wilmotte architects together with Elioth structural engineers. It has a capacity of 35,000 seats. Its roof structure consists of a complex 3D shape timber and steel lattice and is covered by 25,000m² of ETFE, 10,500m² of PES-PVC fabric and 8,500m² of photovoltaic panels. This paper focuses on the ETFE part of the cover. The stadium is one of the first constructions to use flat single layer ETFE on such a big area. Due to its relatively recent appearance in France, ETFE structures are not yet covered by any regulations and the existing codes for fabric structures cannot be strictly applied. Rather, they are considered as cladding systems and therefore have to be approved by an “Appréciation Technique d’Expérimentation” (ATEx), during which experimental tests have to be performed. We explain the method that we developed to justify the ETFE, which eventually led to bi-axial tests to clarify the allowable stress in the film.

Keywords: biaxial test, creep, ETFE, single layer, stadium roof

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Authors: Tianyue Wan

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Lost space is the space that has not been used for a long time and is in decline, proposed by Roger Trancik. And in his book Finding Lost Space: Theories of Urban Design, the concept of lost space is defined as those anti-traditional spaces that are unpleasant, need to be redesigned, and have no benefit to the environment and users. They have no defined boundaries and do not connect the various landscape elements in a coherent way. With the rapid development of urbanization in China, the blind areas of urban renewal have become a chaotic lost space that is incompatible with the rapid development of urbanization. Therefore, lost space needs to be reconstructed urgently under the background of infill development and reduction planning in China. The formation of lost space is also an invisible division of social hierarchy. This paper tries to break down the social class division and the estrangement between people through the regeneration of lost space. Ultimately, it will enhance vitality, rebuild a sense of belonging, and create a continuous open public space for local people. Based on the concept of lost space and energy field, this paper clarifies the significance of the energy field in the lost space renovation. Then it introduces the energy field into lost space by using the magnetic field in physics as a prototype. The construction of the energy field is support by space theory, spatial morphology analysis theory, public communication theory, urban diversity theory and city image theory. Taking Wuhan’s Lingjiao Park of China as an example, this paper chooses the lost space on the west side of the park as the research object. According to the current situation of this site, the energy intervention strategies are proposed from four aspects: natural ecology, space rights, intangible cultural heritage and infrastructure configuration. And six specific lost space renewal methods are used in this work, including “riveting”, “breakthrough”, “radiation”, “inheritance”, “connection” and “intersection”. After the renovation, space will be re-introduced into the active crow. The integration of activities and space creates a sense of place, improve the walking experience, restores the vitality of the space, and provides a reference for the reconstruction of lost space in the city.

Keywords: dynamic vitality intervention, lost space, space vitality, sense of place

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Authors: Yudhitya Kusumawati, Yuki Mitsuya, Tomooki Shiba, Mitsuru Uesaka

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After the Fukushima Daiichi nuclear power reactor incident, there are a lot of unaccountable nuclear fuel debris in the reactor core area, which is subject to safeguard and criticality safety. Before the actual precise analysis is performed, preliminary on-site screening and mapping of nuclear debris activity need to be performed to provide a reliable data on the nuclear debris mass-extraction planning. Through a collaboration project with Japan Atomic Energy Agency, an on-site nuclear debris screening system by using dual energy X-Ray inspection and neutron energy resonance analysis has been established. By using the compact and mobile pulsed neutron source constructed from 3.95 MeV X-Band electron linac, coupled with Tungsten as electron-to-photon converter and Beryllium as a photon-to-neutron converter, short-distance neutron Time of Flight measurement can be performed. Experiment result shows this system can measure neutron energy spectrum up to 100 eV range with only 2.5 meters Time of Flightpath in regards to the X-Band accelerator’s short pulse. With this, on-site neutron Time of Flight measurement can be used to identify the nuclear debris isotope contents through Neutron Resonance Transmission Analysis (NRTA). Some preliminary NRTA experiments have been done with Tungsten sample as dummy nuclear debris material, which isotopes Tungsten-186 has close energy absorption value with Uranium-238 (15 eV). The results obtained shows that this system can detect energy absorption in the resonance neutron area within 1-100 eV. It can also detect multiple elements in a material at once with the experiment using a combined sample of Indium, Tantalum, and silver makes it feasible to identify debris containing mixed material. This compact neutron Time of Flight measurement system is a great complementary for dual energy X-Ray Computed Tomography (CT) method that can identify atomic number quantitatively but with 1-mm spatial resolution and high error bar. The combination of these two measurement methods will able to perform on-site nuclear debris screening at Fukushima Daiichi reactor core area, providing the data for nuclear debris activity mapping.

Keywords: neutron source, neutron resonance, nuclear debris, time of flight

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Authors: Tomas Vincze, Michal Micjan, Milan Pavuk, Martin Weis

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In recent years, alternative materials are gaining attention to replace polycrystalline and amorphous silicon, which are a standard for low requirement devices, where silicon is unnecessarily and high cost. For that reason, metal oxides are envisioned as the new materials for these low-requirement applications such as sensors, solar cells, energy storage devices, or field-effect transistors. Their most common way of layer growth is sputtering; however, this is a high-cost fabrication method, and a more industry-suitable alternative is the sol-gel method. In this group of materials, many oxides exhibit a semiconductor-like behavior with sufficiently high mobility to be applied as transistors. The sol-gel method is a cost-effective deposition technique for semiconductor-based devices. Copper oxides, as p-type semiconductors with free charge mobility up to 1 cm2/Vs., are suitable replacements for poly-Si or a-Si:H devices. However, to reach the potential of silicon devices, a fine-tuning of material properties is needed. Here we focus on the optimization of the electrical parameters of copper oxide-based field-effect transistors by modification of precursor solvent (usually 2-methoxy ethanol). However, to achieve solubility and high-quality films, a better solvent is required. Since almost no solvents have both high dielectric constant and high boiling point, an alternative approach was proposed with blend solvents. By mixing isopropyl alcohol (IPA) and 2-methoxy ethanol (2ME) the precursor reached better solubility. The quality of the layers fabricated using mixed solutions was evaluated in accordance with the surface morphology and electrical properties. The IPA:2ME solution mixture reached optimum results for the weight ratio of 1:3. The cupric oxide layers for optimal mixture had the highest crystallinity and highest effective charge mobility.

Keywords: copper oxide, field-effect transistor, semiconductor, sol-gel method

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Authors: Khaled R. Khater

Abstract:

The weight of the SPT hammer is standard (0.623kN). The locally manufacturer drilling rigs use hammers, sometimes deviating off the standard weight. This affects the field measured blow counts (Nf) consequentially, affecting most of correlations previously obtained, as they were obtained based on standard hammer weight. The literature presents energy corrections factor (η2) to be applied to the SPT total input energy. This research investigates the effect of the hammer weight variation, as a single parameter, on the field measured blow counts (Nf). The outcome is a correction factor (ηk), equation, and correction chart. They are recommended to adjust back the measured misleading (Nf) to the standard one as if the standard hammer is used. This correction is very important to be done in such cases where a non-standard hammer is being used because the bore logs in any geotechnical report should contain true and representative values (Nf), let alone the long records of correlations, already in hand. The study here-in is achieved by using laboratory physical model to simulate the SPT dripping hammer mechanism. It is designed to allow different hammer weights to be used. Also, it is manufactured to avoid and eliminate the energy loss sources. This produces a transmitted efficiency up to 100%.

Keywords: correction factors, hammer weight, physical model, standard penetration test

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Authors: Jyh-Cherng Chen, Yu-Zen Lin, Wei-Zhi Chen

Abstract:

Torrefaction is one of waste to energy (WTE) technologies developing in Taiwan recently, which can reduce the moisture and impurities and increase the energy density of biowaste effectively. To understand the torrefaction characteristics of different biowaste and the influences of different torrefaction conditions, four typical biowaste were selected to carry out the torrefaction experiments. The physical and chemical properties of different biowaste prior to and after torrefaction were analyzed and compared. Experimental results show that the contents of elemental carbon and caloric value of the four biowaste were significantly increased after torrefaction. The increase of combustible and caloric value in bamboo was the greatest among the four biowaste. The caloric value of bamboo can be increased from 1526 kcal/kg to 6104 kcal/kg after 300oC and 1 hour torrefaction. The caloric value of torrefied bamboo was almost four times as the original. The increase of elemental carbon content in wood was the greatest (from 41.03% to 75.24%), and the next was bamboo (from 47.07% to 74.63%). The major parameters which affected the caloric value of torrefied biowaste followed the sequence of biowaste kinds, torrefaction time, and torrefaction temperature. The optimal torrefaction conditions of the experiments were bamboo torrefied at 300oC for 3 hours, and the corresponding caloric value of torrefied bamboo was 5953 kcal/kg. This caloric value is similar to that of brown coal or bituminous coal.

Keywords: torrefaction, waste to energy, calorie, biofuel

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Authors: Felice De Luca, Vincenzo Galdi, Piera Stella, Vito Calderaro, Adriano Campagna, Antonio Piccolo

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Sustainable mobility has become one of the major issues of recent years. The challenge in reducing polluting emissions as much as possible has led to the production and diffusion of vehicles with internal combustion engines that are less polluting and to the adoption of green energy vectors, such as vehicles powered by natural gas or LPG and, more recently, with hybrid and electric ones. While on the one hand, the spread of electric vehicles for private use is becoming a reality, albeit rather slowly, not the same is happening for vehicles used for public transport, especially those that operate in the congested areas of the cities. Even if the first electric buses are increasingly being offered on the market, it remains central to the problem of autonomy for battery fed vehicles with high daily routes and little time available for recharging. In fact, at present, solid-state batteries are still too large in size, heavy, and unable to guarantee the required autonomy. Therefore, in order to maximize the energy management on the vehicle, the optimization of driving profiles offer a faster and cheaper contribution to improve vehicle autonomy. In this paper, following the authors’ precedent works on electric vehicles in public transport and energy management strategies in the electric mobility area, an eco-driving strategy for electric bus is presented and validated. Particularly, the characteristics of the prototype bus are described, and a general-purpose eco-drive methodology is briefly presented. The model is firstly simulated in MATLAB™ and then implemented on a mobile device installed on-board of a prototype bus developed by the authors in a previous research project. The solution implemented furnishes the bus-driver suggestions on the guide style to adopt. The result of the test in a real case will be shown to highlight the effectiveness of the solution proposed in terms of energy saving.

Keywords: eco-drive, electric bus, energy management, prototype

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Authors: Mark Daniel De Luna, Ma. Katreena Pillejera, Wei-Hsin Chen

Abstract:

The raw bamboo (Phyllostachys mankinoi), with a moisture content of 13.54 % and a higher heating value (HHV) of 17.657 MJ/kg, was subjected to torrefaction under a high gravity (higee) environment using a rotating packed bed. The performance of the higee torrefaction was explored in two parts: (1) effect of rotation and temperature and (2) effect of duration on the solid yield, HHV and energy yield. By statistical analyses, the results indicated that the rotation, temperature and their interaction has a significant effect on the three responses. Same remarks on the effect of duration where when the duration (temperature and rotation) increases, the HHV increases, while the solid yield and energy yield decreases. Graphical interpretations showed that at 300 °C, the rotating speed has no evident effect on the responses. At 30-min holding time, the highest HHV reached (28.389 MJ/kg) was obtained in the most severe torrefaction condition (the rotating speed at 1800 rpm and temperature at 300 °C) with an enhancement factor of HHV corresponding to 1.61 and an energy yield of 63.51%. Upon inspection, the recommended operating condition under a 30-min holding time is at 255 °C-1800 rpm since the enhancement factor of HHV (1.53), HHV (26.988 MJ/kg), and energy yield (65.21%) values are relatively close to that of the aforementioned torrefaction condition. The Van Krevelen diagram of the torrefied biomass showed that the ratios decrease as the torrefaction intensifies, hence improving the hydrophobicity of the product. The spreads of the results of the solid yield, enhancement factor (EF) of HHV, energy yield, and H/C and O/C ratios were in accordance with the trends of the responses. Overall, from the results presented, it can be concluded that the quality of the product from the process is at par to that of coal (i.e. HHV of coal is 21-35 MJ/kg). The Fourier transform infrared (FTIR) spectroscopy results indicated that cellulose and lignin may have been degraded at a lower temperature accompanied with a high rotating speed. The results suggested that torrefaction under higee environment indicates promising process for the utilization of bamboo.

Keywords: heat transfer, high gravity environment, FTIR, rotation, rotating speed, torrefaction

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Authors: C. Hall, J. Ramos, V. Ramasamy

Abstract:

Hydrocarbon-based fuel vehicles are a major contributor to air pollution due to harmful emissions produced, leading to a demand for cleaner fuel types. A leader in this pursuit is hydrogen, with its application in vehicles producing zero harmful emissions and the only by-product being water. To compete with the performance of conventional vehicles, hydrogen gas must be stored on-board of vehicles in cylinders at high pressures (35–70 MPa) and have a short refueling duration (approximately 3 mins). However, the fast-filling of hydrogen cylinders causes a significant rise in temperature due to the combination of the negative Joule-Thompson effect and the compression of the gas. This can lead to structural failure and therefore, a maximum allowable internal temperature of 85°C has been imposed by the International Standards Organization. The technological solution to tackle the issue of rapid temperature rise during the refueling process is to decrease the temperature of the gas entering the cylinder. Pre-cooling of the gas uses a heat exchanger and requires energy for its operation. Thus, it is imperative to determine the least amount of energy input that is required to lower the gas temperature for cost savings. A validated universal thermodynamic model is used to identify an energy-efficient pre-cooling strategy. The model requires negligible computational time and is applied to previously validated experimental cases to optimize pre-cooling requirements. The pre-cooling characteristics include the location within the refueling timeline and its duration. A constant pressure-ramp rate is imposed to eliminate the effects of rapid changes in mass flow rate. A pre-cooled gas temperature of -40°C is applied, which is the lowest allowable temperature. The heat exchanger is assumed to be ideal with no energy losses. The refueling of the cylinders is modeled with the pre-cooling split in ten percent time intervals. Furthermore, varying burst durations are applied in both the early and late stages of the refueling procedure. The model shows that pre-cooling in the later stages of the refuelling process is more energy-efficient than early pre-cooling. In addition, the efficiency of pre-cooling towards the end of the refueling process is independent of the pressure profile at the inlet. This leads to the hypothesis that pre-cooled gas should be applied as late as possible in the refueling timeline and at very low temperatures. The model had shown a 31% reduction in energy demand whilst achieving the same final gas temperature for a refueling scenario when pre-cooling was applied towards the end of the process. The identification of the most energy-efficient refueling approaches whilst adhering to the safety guidelines is imperative to reducing the operating cost of hydrogen refueling stations. Heat exchangers are energy-intensive and thus, reducing the energy requirement would lead to cost reduction. This investigation shows that pre-cooling should be applied as late as possible and for short durations.

Keywords: cylinder, hydrogen, pre-cooling, refueling, thermodynamic model

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Authors: M. A. Wijewardane, S. A. N. C. Sudasinghe, H. K. G. Punchihewa, W. K. D. L. Wickramasinghe, S. A. Philip, M. R. S. U. Kumara

Abstract:

Visual comfort is one of the major parameters that can be taken to measure the human comfort in any environment. If the provided illuminance level in a working environment does not meet the workers visual comfort, it will lead to eye-strain, fatigue, headache, stress, accidents and finally, poor productivity. However, improvements in lighting do not necessarily mean that the workplace requires more light. Unnecessarily higher illuminance levels will also cause poor visual comfort and health risks. In addition, more power consumption on lighting will also result in higher energy costs. So, during this study, visual comfort and the illuminance requirement for the workers in textile/apparel industry were studied to perform different tasks (i.e. cutting, sewing and knitting) at their workplace. Experimental studies were designed to identify the optimum illuminance requirement depending upon the varied fabric colour and type and finally, energy saving potentials due to controlled illuminance level depending on the workforce requirement were analysed. Visual performance of workers during the sewing operation was studied using the ‘landolt ring experiment’. It was revealed that around 36.3% of the workers would like to work if the illuminance level varies from 601 lux to 850 lux illuminance level and 45.9% of the workers are not happy to work if the illuminance level reduces less than 600 lux and greater than 850 lux. Moreover, more than 65% of the workers who do not satisfy with the existing illuminance levels of the production floors suggested that they have headache, eye diseases, or both diseases due to poor visual comfort. In addition, findings of the energy analysis revealed that the energy-saving potential of 5%, 10%, 24%, 8% and 16% can be anticipated for fabric colours, red, blue, yellow, black and white respectively, when the 800 lux is the prevailing illuminance level for sewing operation.

Keywords: Landolt Ring experiment, lighting energy consumption, illuminance, textile and apparel industry, visual comfort

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Authors: Diala Bitar, Emmanuel Gourdon, Claude H. Lamarque, Manuel Collet

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Acoustic absorber devices play an important role reducing the noise at the propagation and reception paths. An electroacoustic absorber consists of a loudspeaker coupled to an electric shunt circuit, where the membrane is playing the role of an absorber/reflector of sound. Although the use of linear shunt resistors at the transducer terminals, has shown to improve the performances of the dynamical absorbers, it is nearly efficient in a narrow frequency band. Therefore, and since nonlinear phenomena are promising for their ability to absorb the vibrations and sound on a larger frequency range, we propose to couple a nonlinear electric shunt circuit at the loudspeaker terminals. Then, the equivalent model can be described by a 2 degrees of freedom system, consisting of a primary linear oscillator describing the dynamics of the loudspeaker membrane, linearly coupled to a cubic nonlinear energy sink (NES). The system is analytically treated for the case of 1:1 resonance, using an invariant manifold approach at different time scales. The proposed methodology enables us to detect the equilibrium points and fold singularities at the first slow time scales, providing a predictive tool to design the nonlinear circuit shunt during the energy exchange process. The preliminary results are promising; a significant improvement of acoustic absorption performances are obtained.

Keywords: electroacoustic absorber, multiple-time-scale with small finite parameter, nonlinear energy sink, nonlinear passive shunt

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Authors: Arif Ferdiyanto, Fajar Hamida, Arif Hidayat

Abstract:

Oil palm empty fruit bunches, derived biomass available in Indonesia, is one of the potential biomass to produce biofuels like bio-oil due to its abundant supply and favorable physicochemical characteristics. An interesting alternative of utilising the oil palm empty fruit bunches is in the production of bio-oil by pyrolysis. Pyrolysis of oil palm empty fruit bunches to bio-oil is being considered for national energy security and environmental advantages. The aim of this study was to produce bio-oil by pyrolysis of oil palm empty fruit bunches at various temperature and observe its detailed chemical composition. The biomass was submitted to a pyrolysis in a batch reactor. Experiments were carried out at a temperature range of 450–600°C and heating rate range of 10-20°C/min. The yield of bio-oil was found to be maximum at the temperature of 600°C. The bio-oils detailed compositions were investigated using FTIR and GC-MS. The bio-char produced as a co-product can be a potential soil amendment with multiple benefits including soil fertility and for solid fuel applications that also contributes to the preservation of the environment. The present investigation suggests the suitability of oil palm empty fruit bunches as a potential feedstock for exploitation of energy and biomaterials through pyrolysis process.

Keywords: bio-oil, oil palm empty fruit bunches, pyrolysis, renewable energy

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Authors: Varun Joshi, Manish K. Rathod

Abstract:

The latent heat thermal energy storage system is a thrust area of research due to exuberant thermal energy storage potential. The thermal performance of PCM is significantly augmented by installation of the high thermal conductivity fins. The objective of the present study is to obtain optimum size and location of the fins to enhance diffusion heat transfer without altering overall melting time. Hence, the constructal theory is employed to eliminate, resize, and re-position the fins. A numerical code based on conjugate heat transfer coupled enthalpy porosity approached is developed to solve Navier-Stoke and energy equation.The numerical results show that the constructal fin design has enhanced the thermal performance along with the increase in the overall volume of PCM when compared to conventional. The overall volume of PCM is found to be increased by half of total of volume of fins. The elimination and repositioning the fins at high temperature gradient from low temperature gradient is found to be vital.

Keywords: constructal theory, enthalpy porosity approach, phase change materials, fins

Procedia PDF Downloads 166