MW Of Electrical Power Research Articles

Energy, exergy and exergoenvironmental analyses on gas-diesel fuel marine engine used for trigeneration system

This study has addressed a trigeneration system driven by dual fuel marine engine. The marine engine manufacturers have developed the dual fuel (DF) version to improve the combustion and reduce the pollutant gaseous emissions. The aim was evaluated the performances of gas diesel fuel and full diesel based on exergy and exergoenvironmental analyses. The energy, exergy and exergoenvironmental balances were conducted considering the effect of pollutant emissions. The specific exergy cost (SPECO) approach was applied, which use the fuel and product definition. The diesel marine engine original produced 6.90 MW of electrical power, 28.16 kW of cooling water and 278.2 and 588 kW of heating. The findings revealed that the effect of gas diesel fuel has reduced the energy and exergy efficiencies by 87% in relation to full diesel mode. The diesel engine has the highest exergy destruction with 3051 kW. The NO emission has a portion of 92% of environmental impact rate associated to pollutant formation. The lowest energy and exergetic efficiencies and the highest environmental impact rates of components were investigated. The environmental impact rate per exergy unit of electricity power, cooling water of absorption chiller and heating water were presented. The reduction of environmental impact rate of pollutant formation is the main responsible for the better environmental performance of gas diesel fuel marine engine. Despite the reduction in energy and exergy efficiencies, the dual fuel (DF) technology was able to controlling pollutant emissions and improved the exergoenvironmental performance without great modification into engine. Further recommendations were proposed.

Biogas from Agri-Food and Agricultural Waste Can Appreciate Agro-Ecosystem Services: The Case Study of Emilia Romagna Region

Agro-ecosystems are intensively exploited environments which are both providers and consumers of ecosystem services. The improvement of both provisioning and regulating services in cultivated landscapes is crucial for the sustainable development of rural areas. Among the provisioning services offered, producing biogas from the anaerobic digestion of residual biomass is nowadays a promising option for decreasing greenhouse gas (GHG) emissions, while avoiding the land use conflicts related to the use of dedicated crops. Based on the available quantitative data at a regional level, provisioning and regulating services provided by the use of agri-food waste, livestock waste and agricultural residues were assessed for the case of Emilia Romagna region, the second biggest biogas producer in Italy. One provisioning service, i.e., bioenergy generation, and three regulating services were considered: (i) air quality improvement by the reduction of odors derived from direct use of waste, (ii) regulation of soil nutrients by reducing organic load and digestate spreading, and (iii) global climate regulation by saving GHG emissions. A potential further generation of 52.7 MW electric power was estimated at the regional level. Digestate spreading on fields may reduce odor impact by more than 90%, while containing a higher percentage of inorganic nitrogen, which is readily available to plants. The estimated GHG emission savings were equal to 2,862,533 Mg CO2eq/yr, mainly due to avoided landfilling for agri-waste and avoided replacing of mineral fertilizers for livestock waste and agricultural residues. The results suggest that bioenergy generation from lignocellulosic, livestock and agro-industrial residues may improve some regulating services in agro-ecosystems, while helping to reach renewable energy targets, thus contributing to overcoming the provisioning vs. regulating services paradigm in human-managed ecosystems.

Flexibility of Power‐to‐Gas Plants: A Case Study

AbstractDue to the increasing share of renewable energies in the power sector, the need for energy storage and flexible performance is rising. This study provides an in‐depth investigation of the flexibility of a Power‐to‐Gas plant for the production of synthetic natural gas. Model‐based analysis is conducted for the individual technologies PEM electrolysis, MEA absorption and fixed‐bed methanation as well as for the continuously operated process. This study reveals that the Power‐to‐Gas plant offers a capacity flexibility of 87–125 %, corresponding to 4.79–6.88 MW electrical input power.

Development of a clean power plant integrated with a solar farm for a sustainable community

Renewable energy sources are attracting attention as a replacement of fossil fuel-based sources. This paper presents a new renewable combined cycle power plant to deliver smart services for a sustainable community. A case study is undertaken for the Kedron Community in the city of Oshawa in Canada. The integrated power plant depends on solar radiation and seawater. The services produced are electric power, heating load, fresh water, and liquified hydrogen as a clean fuel. The combined plant consists of six subsystems: solar farm, Gas turbine cycle, Rankine cycle, multi-effect desalination, electrolyzer, and hydrogen liquefaction subsystem. The integrated system has been studied thermodynamically to investigate the thermal and exergy performance. The solar farm uses HITEC with a mass flow rate of 2000 kg/s to produce an overall heat of 201.3 MW to the combined cycle. The combined cycle delivers 133.1 MW of electric power, a heating load of 284 MW for desalination, and a heating load of 98.2 MW for residential applications. The multistage flash desalination system provides 684 kg/s of fresh water, where 32.09 kg/s is used for electrolysis to produce hydrogen gas. The hydrogen liquefaction system consists of nitrogen precooling refrigeration system, hydrogen Claude refrigeration system, and hydrogen liquefying stream. This liquefaction system produces 355 ton/day of liquefied hydrogen with SFC of 5.24 kWh/kg-LH2. The overall thermal efficiency of the integrated system is 88.12%, while the exergetic efficiency is 23.05%.

Exploiting ultralow-frequency energy via vibration-to-rotation conversion of a rope-spun rotor

Ultralow-frequency kinetic energy mainly in the form of vibrations is omnipresent in the environment, but its effective exploitation remains a challenge. To tackle this problem, this paper presents a rope-spun rotor structure to transform ultralow-frequency vibrations/linear motions to rapid rotations through a piece of rope. The superior performance of the rotor is demonstrated by applying it to electromagnetic energy harvesting from ultralow-frequency vibrations and irregular human body motions. When the rope-spun rotor based harvester is periodically pushed down 10.5 mm at 1.5 Hz, it produces 9.7 mW electric power. When embedded in a shoe insole, the harvester delivers 8 mW power to a matched load as a male participant walks with the shoe at 6.5 km/h. When positioned under a piece of floorboard, the harvester can charge a supercapacitor (220 mF) from 0 to 3.5 V within 8 min. The harvester can also sustain the continuous operation of multiple electronics simultaneously by scavenging energy from gentle finger tapping motions. This study demonstrates a new mechanism for realizing vibration-to-rotation conversion and a promising way for efficient harvesting of ultralow-frequency energy.

Estimated View of Renewable Resources as a Sustainable Electrical Energy Source, Case Study

Renewable energy resources for energy generation in the Gaza Strip (GS) emerge as a complementary resource, not only to meet the need of society for energy in various forms, but also to find available, sustainably, and less costly resources for institutions as with individuals. These resources could provide safety in use, increase energy security, and address environmental concerns. This work aimed to assess the renewable energy potential in the GS, which has few natural resources and a real crisis in energy supply. Therefore, an integrated evaluation methodology is assumed for renewable energy potential; the methodology comprises mathematical as well as software programming to assess the renewable energy. The results reveal the assessment of the existing four renewable energy sources: solar, wind, wave, and biomass. The estimations exhibit that the solar and biomass resources are dominant. The methodology consists of mathematical models for calculating the energy outputs from different resources in the study area. ArcGIS 10.1 software used for calculating solar radiation, WindSim 9.0.0 software for estimating wind energy and OpenWEC software tool for evaluating the force stored in coastal waves. The potential of each energy and the integration of all are depicted in individual maps by ArcGIS. It was found that if anaerobic digestion technology is applied, 65.15 MW electric power could be produced from about one-and a third million tons/year of biomass. Depending on the available statistical data due to the specified annual time period and the household electric demand that is about 120 MW at the corresponding time, this means that the energy from biomass can cover more than half of the demand. In addition, solar energy potentials were estimated to reach 1195 GWh/year. Therefore, the existing power may be replaced by biomass and solar energy. It also demonstrates that the energy potential maps can be used as metrics for possible sustainability projects in the GS.

Feasibility analysis of reverse osmosis desalination driven by a solar pond in Mediterranean and semi-arid climates

Solar desalination is emerging as a sustainable solution for water shortage in countries having limited access to conventional energy resources. This paper proposes an autonomous desalination system fully powered by solar energy. This system mainly consists of a salt gradient solar pond coupled to an organic Rankine cycle that drives the pumps of a reverse osmosis desalination unit. For each of these three components, a theoretical model is elaborated, and validated with numerical and/or experimental data. Then, each model is combined with a genetic algorithm to determine the optimal design and operating parameters. The optimization tests revealed that the hybrid pressure vessel can produce fresh water at a salinity of 376.6 mg/l with a specific energy consumption of about 2.1 kWh/m3. A recuperative organic Rankine cycle was optimized to supply the desalination unit, composed of 31 hybrid pressure vessels and 3 pressure exchanger devices, with 0.28 MW of electric power with an exergy efficiency around 54%. In addition, the results predicted that the solar pond land required to run the desalination unit at a daily drinking water production of about 2380.8 m3 is almost 33.6% smaller in the semi-arid climate compared to the Mediterranean one. The designed desalination plant can supply drinking water over 73.3% of the year, 61.2% of whom without interruption, in semi-arid climate compared to only 50% in the Mediterranean one. The discussion of the results includes some technics suggested to enhance the feasibility of the current plant.

Strategies to Promote Biogas Generation and Utilisation from Palm Oil Mill Effluent

Palm oil mills generate a large amount of wastewater, known as palm oil mill effluent, during the production of crude palm oil. The high organic contents in palm oil mill effluent have an excellent potential for biogas utilisation. Besides, such effluent must be further treated before discharge or reused in milling processes. In this respect, an integrated biogas and wastewater treatment system should be developed. The aim of this paper is to synthesise and optimise an integrated biogas and wastewater treatment system via a process systems engineering tool that yields maximum economic performance. To illustrate the proposed approach, a typical palm oil mill case study in Malaysia is presented. The variation in palm oil mill effluent availability is considered to evaluate the changes in performance and ensuring the flexibility of the developed system. As shown in the results, implementation of integrated biogas and wastewater treatment system in a typical 60 t/h mill in Malaysia could export up to 1.9 MW electrical power on average. Alternatively, 110,800 GJ/year of compressed biomethane can be produced when feed-in to the national grid is not available. The implementation of integrated biogas and wastewater treatment system successfully reduces greenhouse gas emissions by 50,430 t CO2e/year as compared with the conventional open ponding system practiced in the industry. Lastly, feasibility studies and strategies to promote biogas utilisation in the industry are performed.

Reservoir simulation of Ulumbu geothermal field using TOUGH2 and ITOUGH2 simulator

Ulumbu geothermal field is classified as a natural two-phase geothermal system, located in the south of Mandosawu - Ranakah Old volcanics and Pocoleok, Flores Island. This field produces 4 x 2.5 MW electric power in 2014 until now with temperature between 230–240 °C. This study aims to perform reservoir simulation in the Ulumbu field. The reservoir simulation method aims to determine the reservoir characteristics of the geothermal field. This research used TOUGH2 and ITOUGH2 simulator to simulate the reservoir. The work concept from TOUGH2 is forward modeling while ITOUGH2 is inverse modeling. Both of methods will produce an output. The output of this research is natural state model that was validated by three wells of the actual measurement (pressure and temperature) and heat flow from the conceptual model. A pressure and temperature profiles are very representative with the data in the three wells. The reservoir location is between Poco Leok and Poco Rii (upflow zone) and continues to the southwest (outflow zone) with an average area of 10.5 km2. The top reservoir is at an elevation of 500 m, while the depth is up to -2000 m. Reservoir rock has a permeability value of around 10−14–10−15 m2, porosity value of 8–10 %, density value of 2500 kg/m3, and specific heat capacity value of 900 J/kgK. Temperature distribution results of the natural state model show the hydrogeological profile of the Ulumbu geothermal system. The natural state model is then used to help undertake a geothermal field development scenario, that is, to calculate resource reserves and to make recommendations for subsequent drilling zones.

A regional integrated energy system with a coal-fired CHP plant, screw turbine and solar thermal utilization: Scenarios for China

Regional integrated energy system has been a suitable scheme in China to satisfy eco-industrial park’s both electric and heat needs. Combined heat and power (CHP) is an efficient technology for coal-fired plants during heating seasons. Currently, wires transport electric from CHP to destination while urban pipes network transport heat from CHP to destination, respectively. However, this might not be the case in future, when eco-industrial parks are close to plants or pipes network can’t carry enough heat. This paper presents a feasible regional integrated energy system which meets both electric and heat’s needs with steam from CHP while maintaining photothermal resources’ high percent utilization. This system includes a coal-fired CHP plant, pressure matcher, steam supply pipeline, screw turbine and solar thermal utilization part. This paper set up a model of 600 MW electric power CHP with pressure matcher and screw turbine in Ebsilon software. Then the steam supply pipeline and solar thermal utilization part were developed and analyzed based on the basic thermodynamic theories with Beijing and Huzhou’s meteorological statistics taken into consideration. Besides, the operational issues of the regional system were also listed. Meanwhile, the regional integrated energy system was obtained and a lot of characteristics were analyzed. Main devices were further investigated with energy, exergy and entransy analysis. Three extreme working situations were also carried out and discussed in the end. Several useful conclusions were drawn. It’s necessary for China to masterly integrate regional energy system with multi-energy. Moreover, pressure matcher is high-efficient in general under other parameters’ influences. This extracting steam’s technology might be considered in future. Besides, low-stent placed pipeline which can transport high-parameter steam 4 km at most was introduced. A proper mass flow value or lower inlet temperature will both reduce loss of pipeline. Furthermore, heat user side can offer electric power about 9.22 MW, heating acreage about 0.79 km2 to the eco-industrial park. More solar heat’s import, lower upper temperature difference and less sunlight will favor solar thermal utilization part. Higher heat load or lower CHP’s working condition will benefit screw turbine. Peak heat exchanger doesn’t need to work when supply domestic water temperature’s demand is less than 65 °C. The simulation in this paper might give technological statistics to the regional integrated energy system which has CHP and photothermal. This will help to put this energy system into actual use in future.

Preliminary Study of Passengers’ Body Heat Harvesting Potential in Commercial Transport Aircraft

The increasing demands for onboard electrical power of commercial transport aircraft have driven the search for other alternative power sources instead of relying only on the propulsion system. Along with the motivation for renewable and greener energy usage, heat energy harvesting from the passengers’ body while they are seated has been proposed to generate electrical power for the seat’s electronics. This heat energy harvesting concept uses thermoelectric devices that convert energy potential from temperature difference into electrical power based on the phenomenon known as Seebeck effects. The generated electrical power from this method heavily depends on the temperature gradient between the two sides of the thermoelectric generator. Therefore, this study has been made to demonstrate the potential of energy harvesting from the dissipated body heat of the seated aircraft passengers. Overall, based on 20 conducted experimental cases, it has been found out that the average maximum temperature that can be possibly obtained from the passengers’ dissipated body heat is about 35.5 °C. This leads to a maximum temperature difference between the seated passengers’ body and the cabin environment of about 15.5 °C, which can be converted into about 10.23 mW of electrical power per each sensor point in the experiment using a standard thermoelectric generator.

In Vitro Study on Smart Stent for Autonomous Post-Endovascular Aneurysm Repair Surveillance

Endovascular aneurysm repair (EVAR) is an established and reliable surgical treatment of abdominal aortic aneurysm (AAA), where a covered stent is implanted to prevent blood flow in the aneurysm sac. Although current EVAR is an effective technique, it requires long-term monitoring for the post-operative complications (e.g., endoleak, stent occlusion), which usually requires expensive radiologic imaging techniques such as ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI). In this paper, we present an accessible and continuous post-EVAR surveillance scheme by developing a smart stent that features ultrasonic powering, blood flow sensing, and integrated wireless electronics. As the body of the smart stent, a piezoelectric membrane with a custom pore architecture is utilized. The benefits of the embedded pore architectures include the expansion and contraction to comply with a minimally invasive procedure and enhanced ultrasonic powering and sensing capability. The smart stent is able to expand up to 112% in diameter when stretched due to the negative Poisson's ratio. The ultrasound generates 0.23 mW of electrical power, which can sufficiently operate a low power wireless electronics. A comprehensive operation of the smart stent is demonstrated in vitro. The integrated flow sensor can measure blood flow ranging between 30 mL/min to 980 mL/min with an average sensitivity of 0.11 mV/mL/min. The wireless electronics transmit and receive such blood flow rate data by modulating the carrier frequency from 81 to 88 MHz from 1 m away. The developed smart stent prototype is the first step towards minimizing post-EVAR complications by providing early and frequent access to diagnostic information to patients and physicians.

Renewable Energy from Cooking Stove Waste Heat Energy using Thermoelectric Generator for Night Market Application

Malaysia night market normally operated along a temporarily closed road. No electrical power provided by the authorities and therefore hawkers need to prepare their own. Currently, they are working with gasoline-electric generator. On top of the cost incurred, they also need to consume exhaust gas and noise from the machine. Further, this situation will also affect customers. With a high percentage of the hawkers involve with cooking activities using the LPG gas stove, excess heat is one of the potential energy which can be converted into electrical energy using a thermoelectric generator (TEG). The aim of this study is to convert the excess heat available used to powered night market electrical facilities. A set of experiments was conducted utilizing five units of TEG connected in series to convert excess heat from a butane gas stove to electrical power. The temperature at both the hot and cold sides of the TEG was recorded used to analyze the effect of power produced. Two electrical parameters namely voltage and current outputs were measured used to calculate the electrical power generated. The analysis focused on the two main governing parameters namely temperature different and Seebeck coefficient toward power generated. It was found that only some amount of excess heat was converted which produced up to 46.8 mW electrical power. This is based on the high temperature recorded at the cold side of the TEG. The almost constant trend showed in temperature different was contributed to a small magnitude of the Seebeck coefficient and so for the power generated. The trend showed by the power generated was also almost constant even the temperature on the hot side keep increasing. The energy conversion process was considered success and can be further increased by increasing the number of TEG units used as well as by incorporating a cooling mechanism as practiced by many researchers.

Design and CFD analysis of an industrial fan for a concentrating high-temperature solar powerplant

The increasing request for the use of renewable energy sources leads to the study of different types of new alternative powerplants, one of them being the electricity generation by means of solar concentration powerplants with open volumetric receiver, using non-pressurized air as the heat transfer fluid. Due to the poor heat transfer characteristics of the fluid, a large air mass flowrate is needed in the solar tower to transfer a sufficient amount of heat to a conventional steam cycle. The aim of this study is to design a machine with 5 MW electrical power output and 1.125 compression ratio that is able to work in this severe environment. The compression needed by the forced convection circuit, requires verification of the relevance of the compressibility phenomena. The design start from the machine type selection and the sizing of the compressor, based on the standard mono-dimensional turbomachinery theory, and continue with the verification of the fluid dynamic performance of the fan, based on a commercial CFD code (ANSYS-FLUENT). A first 2D case is evaluated to ensure that the geometry is working correctly, then the full 3D geometry is simulated to quantify the real performance of the compressor. A preliminary structural analysis of the blade is also performed to verify the structural integrity of the chosen configuration.

The potential of electrical power generation based on organic waste utilization at Tamangapa landfill Makassar

Waste is one of environmental pollution contributor. Waste utilization for electrical generation is an alternative solution. Based on existing data, average amount of waste at Tamangapa landfill Makassar in 2010-2016 were 223,637 tons. The organic waste was approximately 50%, around to 111,818 tons. With rotary kiln incinerator technology, the calculation result showed that existing organic waste (2010-2016) could to generate 29.678 MW of electrical power or 259,978.345 MWh of electrical energy. The prediction by trend analysis method states that in 2026, the amount of organic waste can reach 176,230,390 tons. It can generate 46.773 MW of electrical power or 409,735.657 MWh of electrical energy. This value is equivalent with construction of two distributed generation (DG) units with 2x30 MW capacities.

A three-equation thermocline thermal energy storage model for bidisperse packed beds

The present publication introduces a novel three-equation model for the simulation of bidisperse packed beds, typically utilized in thermocline thermal energy storages with filler. These systems aim for the substitution of a large fraction of cost intensive liquid storage material such as molten salts by a cost effective solid storage material. A higher packing density can be achieved by a combination of large and small particles, i.e. a bidisperse packing. For the simulation of such systems, the currently most widely applied Schumann and continuous solid phase models consider the solid phase as single sized spheres with a mean particle diameter derived from the bidisperse packing. The present work introduces a novel approach, where, besides the differential equation for the fluid, two differential equations for the small and for the large particles are applied. The model is validated with bidisperse experimental data from the literature. For comparison a reference case of a 100 MW electric solar thermal power plant is defined and the bidisperse model is compared to the Schumann model in its outcome for four different particle size combinations. In the single blow operation, where the storage volume is charged from uniform temperature, the temperature curves show differences of up to 6.6 Kelvin. If the thermocline is given time to develop over several consecutive cycles, the difference in charging and discharging time of one period reaches up to 3.5%. With the model presented in this work, accuracy of long duration or annual simulations can be significantly increased.

Application of New Design Automation in the Development of the Pregolskaya TPP Automated Process Control System

The article considers the methods for a hierarchical description of complex systems’ engineering, which is the foundation for aggregation and decomposition technology of structurally complicated electrical systems’ computer-aided design. The issues of technology application in the design of the automated process control system, the improvement of these methods, and the expansion of the class of designed systems are discussed. The technology development issue and its application in the automated design of secondary wiring systems in general and TPP essential auxiliaries in particular is considered. The process of introducing the automated design technology at АО Zarubezhenergoproekt, realized in the Elektrika TsVK CAD system, is described. The CAD-based technology was tested in the design of the 0.4 kV alarm and essential auxiliaries' control systems at the Pregolskaya TPP with 4 × 110 MW of electric power. The features of the design process’s organization at the Pregolskaya TPP are provided: the degree of the design institute’s equipment availability with technologies and design automation facilities at the beginning of the project, the assimilation degree of these technologies by the personnel, and the possibility of integrating existing technologies with the new developments. The issues of mutual adaptation of the new technology’s components and routine design procedures and operations existing in the design institute, information flows between the technology components and design groups, and structural units (departments) of the design institute are considered. The quantitative indicators of the information volume transmitted in the design process between the structural units of the design institute, as well as the volumes of design documentation developed in the CAD system, are given. The expected timetable to obtain a result using the new technology is indicated.

Aspects regarding the use of recovered energy for air conditioning

In the paper the authors analyze the possibility of using the energy recovered from combustion gases, for air cooling. The objective is to evaluate the thermal potential of combustion gases from a cogeneration plant with a 3 MW electric power, located in Buzau. The monitoring data for the cogeneration system shows that the average flue gas temperature at the exit to the atmosphere is 125° C and the mass flow rate of the combustion gases is 18351 kg/h. The thermal potential of combustion gases isused for the preparation of hot water at 85°C for the operation of a LiBr-H2O solution absorption plant. Finally, the authors present a comparative study between the classic cooling system using chiller with mechanical vapor compression (VCM) and the absorption plant supplied by recovered energy from the cogeneration system, high lighting the advantage of the proposed trigeneration system.

A 250 μm × 57 μm Microscale Opto-electronically Transduced Electrodes (MOTEs) for Neural Recording.

Recording neural activity in live animals in vivo with minimal tissue damage is one of the major barriers to understanding the nervous system. This paper presents the technology for a tetherless opto-electronic neural interface based on 180 nm CMOS circuits, heterogeneously integrated with an AlGaAs diode that functions as both a photovoltaic and light emitting diode. These microscale opto-electrically transduced electrodes (MOTEs) are powered by and communicate through an optical interface, simultaneously enabling high temporal-resolution electrical measurements without a tether or a bulky RF coil. The MOTE presented here is 250 μm × 57 μm, consumes 1 μW of electrical power, and is capable of capturing and encoding neural signals before transmitting the encoded signals. The measured noise floor is as low as 15 μVRMS at a 15 kHz bandwidth.

Acoustic metastructure for effective low-frequency acoustic energy harvesting

In this study, a multifunctional acoustic metastructure is proposed to achieve both effective low-frequency sound isolation and acoustic energy harvesting. A metallic substrate with proof mass is adopted to generate the local resonant phenomenon for the purpose of overcoming the drawbacks of the previous rubber film-based acoustic metastructure; the latter usually requires an elaborate tension process. Numerical simulations show that the proposed structure exhibits excellent noise isolation performance in the low-frequency band. Meanwhile, the incident sound energy can be converted into electrical energy with the help of an added piezoelectric patch. Numerical simulation results indicate that the harvested energy can reach the mW level. The parameters’ influence on the metastructure’s vibro-acoustic and energy harvesting performance are discussed in detail. An optimized configuration is selected and used for experimental study. It is demonstrated that 0.21 mW electrical power at 155 Hz can be harvested by the proposed metastructure under 114 dB sound pressure excitation.