scholarly journals On-Off Control Strategy in a BWRO System under Variable Power and Feedwater Concentration Conditions

2020 ◽  
Vol 10 (14) ◽  
pp. 4748 ◽  
Author(s):  
A. Ruiz-García ◽  
I. Nuez
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Water Shortage ◽  
Input Power ◽  
Optimal Operation ◽  
Computational Tool ◽  
Second Stage ◽  
Variable Power ◽  
Two Stages

Although reverse osmosis (RO) is the technology of choice for solving water shortage problems, it is a process that consumes large amounts of energy. Brackish water (BW) desalination is more efficient than seawater desalination due to the lower salinity of the feedwater source. This makes coupling renewable energy sources with BWRO systems attractive. The operation of this type of systems is complex and requires the design of control strategies to obtain optimal operation. The novelty of this work was to propose a simple on-off control strategy for operating a BWRO system that can work with one and two stages and with different configurations considering six spiral wound membrane elements per pressure vessel (PV). The feedwater quality variations of a real groundwater well were used together with a computational tool to simulate the response of the different configurations with the purpose of selecting the most appropriate depending on the input power to the BWRO system. The most suitable configurations were found to be 1:0, 2:1 and 3:2 (PV first stage:PV second stage). It was additionally found that increased feedwater concentrations resulted in shorter operating ranges to maximize permeate water production for the 1:0 and 2:1 configurations, and that the 3:2 configuration was the most suitable for most of the operating range.

scholarly journals Efficiency Enhancement of Non-Isolated DC-DC Interleaved Buck Converter for Renewable Energy Sources

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4127
Author(s):  
Matej Bereš ◽  
Dobroslav Kováč ◽  
Tibor Vince ◽  
Irena Kováčová ◽  
Ján Molnár ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Control Strategy ◽  
Renewable Energy Sources ◽  
Input Power ◽  
Buck Converter ◽  
Experimental Results ◽  
Energy Sources ◽  
Efficiency Enhancement ◽  
The Common ◽  
The Right

The article describes the principles based on which it is possible to obtain energy from renewable sources more efficiently. The principles use the conventional DC-DC interleaved buck converter based on the common electronic component types and the control strategy. A novelty of such a proposed solution lies in the methods which are not new, but with the right combination, better results can be achieved. The resulting method can be implemented into various topologies where the highest efficiency for wide input power is required. In case of the renewable energy sources where the power can vary hugely during the day, the proposed method can be implemented. Therefore, the article provides several steps, from calculation through simulation to experimental results that brings reader close to understanding of a such proposed solution.

scholarly journals An Investigation Of The Performance Of District Heating Substations Using Computer Simulation

2021 ◽  
Author(s):  
Edmund Wong
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Temperature Drop ◽  
District Heating ◽  
Computational Tool ◽  
Energy Conserving ◽  
Simulation Results ◽  
Operation Parameters ◽  
The Impact ◽  
Industry Professionals

Low primary temperature drop across district heating substations is an undesirable phenomenon observed in the district heating industry. Professionals in the industry have argued that this is caused by inappropriate sizing and controls of district heating substations. The thesis aims to investigate the impact of design and operation parameters on the performance of district heating substations, so that building designers and engineers can potentially better design and operate new and existing district heating substations. The thesis shows that, by developing and using a physical model as a computational tool for sensitivity analysis, different design and operation parameters can be evaluated. This generates insights for energy conserving control strategies to be developed. A preliminary control strategy was proposed for district heating substations, and simulation results show energy saving potentials.

scholarly journals A Review on Direct Power Control for Applications to Grid Connected PWM Converters

2015 ◽  
Vol 5 (4) ◽  
pp. 841-849 ◽  
Author(s):  
T. A. Trivedi ◽  
R. Jadeja ◽  
P. Bhatt
Keyword(s):  
Power Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Direct Power ◽  
Direct Power Control ◽  
Pwm Converters ◽  
Induction Generators ◽  
Pwm Rectifiers ◽  
Ac Converters

The Direct Power Control strategy has become popular as an alternative to the conventional vector oriented control strategy for grid connected PWM converters. In this paper, Direct Power Control as applied to various applications of grid connected converters is reviewed. The Direct Power Control for PWM rectifiers, Grid Connected DC/AC inverters applications such as renewable energy sources interface, Active Power Filters, Doubly Fed Induction Generators and AC-DC-AC converters are discussed. Control strategies such as Look-Up table based control, predictive control, Virtual Flux DPC, Model based DPC and DPC-Space Vector Modulation are critically reviewed. The effects of various key parameters such as selection of switching vector, sampling time, hysteresis band and grid interfacing on performance of direct power controlled converters are presented.

Simulation Analysis and Study of Energy Control Strategy for an Extended-Range Electric Vehicle

2014 ◽  
Vol 602-605 ◽  
pp. 962-965 ◽  
Author(s):  
Ji Gao Niu ◽  
Chun Hua Xu
Keyword(s):  
Electric Vehicle ◽  
Fuel Economy ◽  
Control Strategy ◽  
Simulation Analysis ◽  
Control Strategies ◽  
Optimal Operation ◽  
Control Effect ◽  
Extended Range ◽  
Fuel Economy Evaluation ◽  
Set Up

The basic configuration and operation modes of the series extended-range electric vehicle were analyzed and a new method of engine choice and fuel economy evaluation was proposed. A co-simulation platform is set up with Cruise and Matlab/Simulink to evaluate the rule-based engine on-off and optimal operation line control strategies. The simulation results with typical driving cycles illustrate that: firstly, the engine on-off control strategy makes engine and generator operate on their best efficiency points, and its fuel economy is better than optimal operation line control strategy; secondly, when the optimal operation line control strategy is adopted in Extended-Range Mode, the engine downsizing will be beneficial and the extended-range electric vehicle (E-REV) will achieve a better fuel economy and control effect.

scholarly journals Application of optimal control for power systems considering renewable energy technologies

2021 ◽  
Author(s):  
◽  
Dhanpal Chetty
Keyword(s):  
Optimal Control ◽  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Wind Energy ◽  
Control Strategy ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Optimal Control Strategy ◽  
Interconnected Power System

Over the last decade, power generation from renewable energy sources such as wind, hydro and solar energies have substantially increased globally and in South Africa. Of all the renewable energy sources, wind energy appears to be the most promising, considering design and costs. However, due to the intermittent nature of wind, the increased integration of wind energy into existing power systems raises several control challenges related to load frequency control (LFC) and tie-line power system stability. The stability of modern power systems, incorporating wind energy generations, will be significantly enhanced with the development of LFC strategies based on modern control theory, which is the focus of this research. This thesis presents the design, modelling and analysis, of two LFC control strategies for interconnected power systems, having wind power integrations. The first design is an optimal control strategy, based on error minimization through full state vector feedback, for a two-area interconnected power system consisting of hydro-thermal generations. The second design is a model predictive control (MPC) strategy, based output vector feedback of system state parameters, for a two-area interconnected power system consisting of thermal generations in each area. Both designs include the active power support from doubly fed induction generator based wind turbines (DFIG) in conjunction with the combined effort of a thyristor control phase shifter (TCPS) and super conducting magnetic energy storage unit (SMES). Both control strategies were simulated in MATLAB Simulink and positive results were obtained. The results show that the optimal control strategy is enhanced with power integrations using DFIG based wind turbines combined with the TCPS-SMES units and the MPC strategy is very robust and provides better dynamic performances even with parameter variations and generation rate restrictions.

scholarly journals A Scalable Control Strategy for CHB Converters in Photovoltaic Applications

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 208
Author(s):  
Álvaro Pérez Mayo ◽  
Ainhoa Galarza ◽  
Asier López Barriuso ◽  
Javier Vadillo
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Power Plants ◽  
Large Scale ◽  
Pulse Width Modulation ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Bridge Model ◽  
Zero Sequence ◽  
Modular Converters

Renewable energy sources are becoming more relevant in recent decades in power generation, leading to investment in developing efficient systems. Specifically, in photovoltaic energy, modular converters are attracting interest since their characteristics enable them to work at high voltage and optimize the generated energy. However, the control strategies found the literature limit the scalability potential of modular converters. The main aim of this paper is to propose a scalable control strategy for a grid-tied CHB (Cascaded H-Bridge) converter for large-scale photovoltaic power plants. The control proposed is able to take full advantage of converter scalability and modularity, being based on the parameters needed for bipolar sinusoidal PWM (Pulse Width Modulation), and thus reducing the calculus required and simplifying its implementation. Power imbalances are overcome including the zero-sequence vector injection to allow power exchange between phases. Furthermore, the parameter used for power factor control has been discretized and discretization time analysis shows that the control strategy is stable and does not require a high-speed communication channel. For validation purposes, simulations are conducted on a downsized 12 H-bridge model.

scholarly journals An Investigation Of The Performance Of District Heating Substations Using Computer Simulation

2021 ◽  
Author(s):  
Edmund Wong
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Temperature Drop ◽  
District Heating ◽  
Computational Tool ◽  
Energy Conserving ◽  
Simulation Results ◽  
Operation Parameters ◽  
The Impact ◽  
Industry Professionals

Low primary temperature drop across district heating substations is an undesirable phenomenon observed in the district heating industry. Professionals in the industry have argued that this is caused by inappropriate sizing and controls of district heating substations. The thesis aims to investigate the impact of design and operation parameters on the performance of district heating substations, so that building designers and engineers can potentially better design and operate new and existing district heating substations. The thesis shows that, by developing and using a physical model as a computational tool for sensitivity analysis, different design and operation parameters can be evaluated. This generates insights for energy conserving control strategies to be developed. A preliminary control strategy was proposed for district heating substations, and simulation results show energy saving potentials.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

Distributed Entropy Energy-Efficient Clustering algorithm for cluster head selection (DEEEC)

2020 ◽  
Vol 39 (6) ◽  
pp. 8139-8147
Author(s):  
Ranganathan Arun ◽  
Rangaswamy Balamurugan
Keyword(s):  
Energy Efficient ◽  
Clustering Algorithm ◽  
Cluster Head ◽  
Residual Energy ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Second Stage ◽  
Energy Efficient Clustering ◽  
Two Stages ◽  
Ch Selection

In Wireless Sensor Networks (WSN) the energy of Sensor nodes is not certainly sufficient. In order to optimize the endurance of WSN, it is essential to minimize the utilization of energy. Head of group or Cluster Head (CH) is an eminent method to develop the endurance of WSN that aggregates the WSN with higher energy. CH for intra-cluster and inter-cluster communication becomes dependent. For complete, in WSN, the Energy level of CH extends its life of cluster. While evolving cluster algorithms, the complicated job is to identify the energy utilization amount of heterogeneous WSNs. Based on Chaotic Firefly Algorithm CH (CFACH) selection, the formulated work is named “Novel Distributed Entropy Energy-Efficient Clustering Algorithm”, in short, DEEEC for HWSNs. The formulated DEEEC Algorithm, which is a CH, has two main stages. In the first stage, the identification of temporary CHs along with its entropy value is found using the correlative measure of residual and original energy. Along with this, in the clustering algorithm, the rotating epoch and its entropy value must be predicted automatically by its sensor nodes. In the second stage, if any member in the cluster having larger residual energy, shall modify the temporary CHs in the direction of the deciding set. The target of the nodes with large energy has the probability to be CHs which is determined by the above two stages meant for CH selection. The MATLAB is required to simulate the DEEEC Algorithm. The simulated results of the formulated DEEEC Algorithm produce good results with respect to the energy and increased lifetime when it is correlated with the current traditional clustering protocols being used in the Heterogeneous WSNs.

Analisis Kebutuhan Petunjuk Praktikum Berbasis Keterampilan Proses Sains untuk Mencapai Kemampuan Merancang Eksperimen

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fitriah Khoirunnisa ◽  
Friska Septiani Silitonga ◽  
Veri Firmansyah
Keyword(s):  
Core Competence ◽  
Process Skills ◽  
Learning Materials ◽  
Science Process Skills ◽  
Second Stage ◽  
The Core ◽  
The Core Competence ◽  
Two Stages ◽  
Practical Instruction ◽  
Design Experiments

Penelitian ini bertujuan menganalisis kebutuhan petunjuk praktikum berbasis Keterampilan Proses Sains (KPS) untuk mencapai kemampuan merancang eksperimen pada materi kalor reaksi kalorimetri. Penelitian dilakukan terhadap peserta didik kelas XI SMA Negeri 2 Kota Tanjungpinang. Variabel penelitian mencakup analisis kebutuhan bahan ajar dan analisis kesesuaian Kompetensi Inti (KI) dan Kompetensi Dasar (KD). Jenis penelitian yang dilakukan adalah penelitian deskriptif kualitatif. Tahapan pertama dalam penelitian ini adalah menganalisis kebutuhan bahan ajar dengan cara membandingkan dua petunjuk praktikum yang selama ini telah digunakan di sekolah tersebut, ditinjau dari aspek struktur format penulisan, aspek kreativitas, dan aspek keterampilan proses sains yang terdapat dalam petunjuk praktikum. Sehingga didapatkan kesimpulan bahwa petunjuk praktikum yang selama ini digunakan tidak memberikan kesempatan kepada peserta didiknya untuk merancang eksperimen yang telah ditentukan. Tahapan kedua yaitu menganalisis kesesuaian kompetensi inti dan kompetensi dasar, yang bertujuan untuk menentukan indikator pencapaian kompetensi (IPK) yang akan menjadi acuan dalam mengembangkan petunjuk praktikum berbasis keterampilan proses sains. Dari kedua tahapan yang telah dilakukan maka dapat disimpulkan bahwa peserta didik memerlukan petunjuk praktikum yang mampu mengonstruksi pikiran dan mengaktifkan kinerja mereka, sehingga pendekatan Keterampilan Proses Sains menjadi pilihan dalam mengembangkan petunjuk praktikum yang sesuai dengan karakteristik kurikulum 2013.   This research aims to analyze the needs of Science Process Skills based Practical Instruction to achieve the ability to design experiments on the calor of reaction. This research was done to the students of class XI SMA Negeri 2 Tanjungpinang City. Research Variable includes the analysis of the needs of the learning materials and analysis of the suitability of the Core Competence (KI) and Basic Competence (KD). The type of research conducted is descriptive qualitative research. The first stages in this research is to analyze the needs of learning materials by comparing two practical instructions that had been implementing in the school, from the aspects of the structure of writing format, creativity, and science process skills embedded in practical instructions. The conclusion of this research that current practical instructions does not give an opportunity to the participants to design determined experiments. The second stage, namely analyzing the suitability of core competence and basic competence, which aims to determine the indicators of achievement of the competencies (GPA) which will be a reference in developing process skills-based teaching instructions science. Of the two stages that has been done then it can be concluded that learners need practical instructions to construct  thinking and and their performance, so the Science Process Skills approach is an option in developing practical instruction suitable for the characteristics of the curriculum of 2013.

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