Significant Amount Of Electric Power Research Articles

Energy and Exergy Analysis of a Geothermal Sourced Multigeneration System for Sustainable City

The issue of depleting fossil fuels has emphasized the use of renewable energy. Multigeneration systems fueled by renewables such as geothermal, biomass, solar, etc., have proven to be cutting-edge technologies for the production of different valuable by-products. This study proposes a multigeneration system using a geothermal source of energy. The main outputs include power, space heating, cooling, fresh and hot water, dry air, and hydrogen. The system includes a regenerative Rankine cycle, a double effect absorption cycle and a double flash desalination cycle. A significant amount of electrical power, hydrogen and fresh water is generated, which can be used for commercial or domestic purposes. The power output is 103 MW. The thermal efficiency is 24.42%, while energetic and exergetic efficiencies are 54.22% and 38.96%, respectively. The COPen is found to be 1.836, and the COPex is found to be 1.678. The hydrogen and fresh water are produced at a rate of 0.1266 kg/s and 37.6 kg/s, respectively.

Measuring and rating the energy-efficiency of servers

Abstract Data centers and servers consume a significant amount of electrical power. As future data centers increase in size, it becomes increasingly important to be able to select servers based on their energy efficiency. Rating the efficiency of servers is challenging, as it depends on the software executed on that server and on its load profile. To account for this, a measurement and rating methodology for servers must make use of both realistic and varying workloads. Existing energy-efficiency benchmarks either run standardized application loads at multiple load levels or multiple micro-benchmarks at full load. This does not enable a full analysis of system behavior as the energy efficiency for different kinds of software at low load levels remains unknown. This article introduces a measurement methodology and metrics for energy-efficiency rating of servers. The methodology defines system setup and instrumentation for reproducible results. It is designed to use multiple, specifically chosen workloads at different load levels for a full system characterization. All partial results are aggregated in a final metric that can be used by regulators to define server-labeling criteria. The methodology and workloads have been implemented in the standardized Server Efficiency Rating Tool. We show the applicability and use of the measurement methodology specifically considering its reproducibility, fairness, and relevance. A reproducibility analysis shows that efficiency scores vary with a maximum coefficient of 1.04% for repeated experiments. In addition, we evaluate the proposed metrics by investigating their energy-efficiency rating on a set of 385 different servers and show the relevance of the selected workloads by analyzing relationships to real-world applications.

Prospect of wind energy utilization in Saudi Arabia: A review

In Saudi Arabia, the current production of electric power is mainly relying on crude oil which causes a high percentage of carbon dioxide emissions and no power is generated from any renewable sources. However, recently Saudi Government has announced a development plan ‘The Saudi Vision 2030’ where the target is 20% of the production of power from the renewable sources mainly from solar and wind. Like other countries e.g., China, India, US and UK that produce a significant amount of their electric power from renewable sources. Saudi Arabia has a vast land area where there is a plenty of prospect to install renewable power plants (solar and wind farm) to generate a significant amount of electric power to meet their 2030 target. This paper analyses past 10 years wind data in various location of Saudi Arabia to investigate the feasibility to generate power. This study also recommends the potential locations that are suitable for wind power generation including suggestions of the wind turbine specifications.

THE IMPACT OF ALGORITHMS OF FORMING SWITCHING FUNCTIONS OF THE CONTROL SYSTEM IN MATRIX FREQUENCY CONVERTER ON OUTPUT VOLTAGE THD

The AC electric drive based on induction motors is the key basis for many technical rotation and translation systems. However, it requires a significant amount of electric power. In this regard, its energy efficiency is necessary to increase in order to reduce material costs and the load on electrical power network. Thus, this article provides a review of current algorithms for generating control signals in matrix frequency converters, as well as devices with these algorithms. We have defined the impact of these algorithms on the quality of output voltage in frequency converters. We have identified the scope of use for current control systems in order to achieve a certain quality of output voltage in frequency converters. We have shown that the output voltage quality of the system depends on the number of input voltage phases; pulse-width modulation does not provide the required signal quality

Advanced remediation of uranium-contaminated soil

The existing decontamination method using electrokinetic equipment after acidic washing for uranium-contaminated soil requires a long decontamination time and a significant amount of electric power. However, after soil washing, with a sulfuric acid solution and an oxidant at 65 °C, the removal of the muddy solution using a 100 mesh sieve can decrease the radioactivity of the remaining coarse soil to the clearance level. Therefore, only a small amount of fine soil collected from the muddy solution requires the electrokinetic process for its decontamination. Furthermore, it is found that the selective removal of uranium from the sulfuric washing solution is not obtained using an anion exchanger but rather using a cation exchanger, unexpectedly. More than 90% of the uranium in the soil washing solutions is adsorbed on the S-950 resin, and 87% of the uranium adsorbed on S-950 is desorbed by washing with a 0.5 M Na2CO3 solution at 60 °C.

Flameholding Tendencies of Natural Gas and Hydrogen Flames at Gas Turbine Premixer Conditions

Ground-based gas turbines are responsible for generating a significant amount of electric power as well as providing mechanical power for a variety of applications. This is due to their high efficiency, high power density, high reliability, and ability to operate on a wide range of fuels. Due to increasingly stringent air quality requirements, stationary power gas turbines have moved to lean-premixed operation. Lean-premixed operation maintains low combustion temperatures for a given turbine inlet temperature, resulting in low NOx emissions while minimizing emissions of CO and hydrocarbons. In addition, to increase overall cycle efficiency, engines are being operated at higher pressure ratios and/or higher combustor inlet temperatures. Increasing combustor inlet temperatures and pressures in combination with lean-premixed operation leads to increased reactivity of the fuel/air mixture, leading to increased risk of potentially damaging flashback. Curtailing flashback on engines operated on hydrocarbon fuels requires care in design of the premixer. Curtailing flashback becomes more challenging when fuels with reactive components such as hydrogen are considered. Such fuels are gaining interest because they can be generated from both conventional and renewable sources and can be blended with natural gas as a means for storage of renewably generated hydrogen. The two main approaches for coping with flashback are either to design a combustor that is resistant to flashback, or to design one that will not anchor a flame if a flashback occurs. An experiment was constructed to determine the flameholding tendencies of various fuels on typical features found in premixer passage ways (spokes, steps, etc.) at conditions representative of a gas turbine premixer passage way. In the present work, tests were conducted for natural gas and hydrogen between 3 and 9 atm, between 530 K and 650 K, and free stream velocities from 40 to 100 m/s. Features considered in the present study include a spoke in the center of the channel and a step at the wall. The results are used in conjunction with existing blowoff correlations to evaluate flameholding propensity of these physical features over the range of conditions studied. The results illustrate that correlations that collapse data obtained at atmospheric pressure do not capture trends observed for spoke and wall step features at elevated pressure conditions. Also, a notable fuel compositional effect is observed.

Evaluation of commercial building HVAC systems as frequency regulation providers

The heating, ventilating and air-conditioning (HVAC) systems of large commercial office buildings consume a significant amount of electric power. Instead of passively consuming energy, these systems can provide frequency regulation (FR) services to the electric grid by adjusting the power consumption in response to a signal sent by the electric grid operator. This paper has four primary goals: First, it provides the theoretical support and states the need for using HVAC systems to provide FR. Second, it proposes two methods of using HVAC systems for providing FR – a direct method and an indirect method; these two methods are developed as models and tested in simulation. Third, it addresses the challenges of using commercial building HVAC systems for FR; this motivates the development of a new supervisory control method to support the HVAC system for providing FR service. Fourth, it evaluates the simulated results based on the performance based regulation (PBR) rules proposed by the PJM regional transmission organization; thus, it provides the reference for the future field-testing

Power-Saving Magnetization for Magnetorheological Fluid Control Using a Combination of Permanent Magnet and Electromagnet

This study proposes a mechanism for controlling the viscosity of a magnetorheological fluid (MRF) to save a significant amount of electric power consumed during the magnetization process. The mechanism takes advantage of the magnetization/demagnetization property of permanent magnet materials. It consumes no electric power while maintaining the applied external magnetic field to the MRF. The device can also continuously control the intensity of the magnetic field using very little electric power. The evaluations of the power-saving and the viscosity control performances are reported. It is confirmed that the magnetizing device is very effective in maintaining the magnetic field to the MRF, while saving a significant amount of electric power. The device is especially useful in applications where long duration magnetization necessary.

Gas turbine efficiency enhancement using waste heat powered absorption chillers in the oil and gas industry

In hot climates, the efficiency of energy-intensive industrial facilities utilizing gas turbines for power generation, such as oil refineries and natural gas processing plants (NGPPs), can be enhanced by reducing gas turbine compressor inlet air temperature. This is typically achieved using either evaporative media coolers or electrically-driven mechanical vapor-compression chillers. However, the performance of evaporative media coolers is constrained in high relative humidity (RH) conditions, such as encountered in the Middle East and tropical regions, and such coolers require demineralized water supply, while electrically-driven mechanical vapor-compression chillers consume a significant amount of electric power. In this study, the use of gas turbine exhaust gas waste-heat powered, single-effect water–lithium bromide (H2O–LiBr) absorption chillers is thermo-economically evaluated for gas turbine compressor inlet air cooling scheme, with particular applicability to Middle East NGPPs. The thermodynamic performance of the proposed scheme, integrated in a NGPP, is compared with that of conventional evaporative coolers and mechanical vapor-compression chillers, in terms of key operating parameters, and either demineralized water or electricity consumption, respectively. The results show that in extreme ambient conditions representative of summer in the Persian Gulf (i.e., 55 °C, 80% RH), three steam-fired, single-effect H2O–LiBr absorption chillers utilizing 17 MW of gas turbine exhaust heat, could provide 12.3 MW of cooling to cool compressor inlet air to 10 °C. In the same ambient conditions, evaporative coolers would only provide 2.3 MW cooling capacity, and necessitate consumption of approximately 0.8 kg/s of demineralized water to be vaporized. In addition, mechanical vapor-compression chillers would require an additional 2.7 MW of electric energy to provide the same amount of cooling as H2O–LiBr absorption chillers. The additional electricity generated through gas turbine compressor inlet air cooling using the waste heat powered absorption refrigeration scheme is of approximately 5264 MWh per year, compared to 1774 MWh for evaporative cooling. When integrated with other plant process cooling applications, the proposed scheme would not only permit to both meet gas turbine compressor inlet air cooling loads throughout the year, including peak summer loads, but also provide other process cooling during off-peaks time periods. The economic paypack period of the waste heat recovery scheme is estimated to range from 1.3 to 3.4 years for a three-chiller system based on present and project utility prices for NGPPs in the United Arab Emirates. This study suggests that waste heat absorption refrigeration is an attractive solution to enhance electrical power generation in Middle East NGPPs through gas turbine inlet air cooling, both in terms of thermodynamic and economic feasibility. This strategy would also reduce plant natural gas consumption for power generation, hence production costs and emissions.

Production of highly charged ions with an ECRIS using high temperature super-conducting coils

Highly charged ions are widely used in atomic physics, nuclear physics and material science. One requirement to produce highly charged ions for an ECRIS [P. Sortais et al., ECRIS development at GANIL, in: Proceedings of the 12th Int. Conf. on Cyclotrons, Berlin, 1989; P. Sortais et al., in: Proceedings of the Int. Conf. on Ion sources, Berkley 1989, p. 288] is a high resonance frequency, hence a high resonance magnetic field. With electromagnets, we can produce limited magnetic fields, generally, in the range of 2T. Also, electromagnets require a significant amount of electrical power, powerful DC power supplies and large cooling systems. As a consequence, producing highly charged ions with a source setup, at ground, is rather difficult and becomes a serious technical and financial challenge if the source is on a high voltage terminal. The use of low temperature superconducting coils ‘LTC’ has a real advantage when it comes to electrical power. A reduction factor of 10–20 in the total AC power is obtained. However, the handling of cryogenic liquids generates difficulties and extra costs. An elegant solution consists in using high temperature superconducting wire ‘HTS’ [Y.L. Tang et al., Super Cond. Sci. Technol. 15 (2002); L. Masure et al., 2002, in: ISS2002 Conf. Proc. (Yokohama, Japan, November 2002) in press]. Indeed, the superconductivity of the HTS wire starts at 77K. Cryogenic generators with sufficient cooling power at 20K are commercially available and need only few kW of AC power. In addition to that, the coils are very compact and easy to handle. The following paper presents PKDELIS [ECR HTS source using superconducting coils, French Patent No. FR98 06579]. The first ECRIS in the world using HTS wires, jointly designed and constructed by PANTECHNIK and NSC New Delhi, India.

Piezoelectric Actuation: State of the Art

Significant advances in smart material actuators have taken place in the past decade. The holy grail of actuator research is an architecture that can generate high displacement and force throughout a broad frequency range while not consuming a significant amount of electrical power. The large appeal of using smart material actuators stems from their high mechanical energy density. However, all smart material actuators generally have at least one shortcoming involving either mechanical stroke, force, or frequency capability. Whenever speed is a consideration, piezoelectric actuation is the most commonly employed. The purpose of this paper is to review the most current trends in piezoelectric actuation architectures. The paper does not present the theoretical details of each actuator, but instead strives to highlight the novel concepts used in each design to overcome the stroke limitation of the material.