scholarly journals Comparison of electrical collection topologies for multi-rotor wind turbines

2020 ◽  
Vol 5 (4) ◽  
pp. 1237-1252
Author(s):  
Paul Pirrie ◽  
David Campos-Gaona ◽  
Olimpo Anaya-Lara
Keyword(s):  
Wind Turbines ◽  
Cost Effective ◽  
Capital Cost ◽  
Lower Efficiency ◽  
Energy Capture ◽  
Electrical Systems ◽  
Component Type ◽  
Potential Benefits ◽  
Comparison Table ◽  
Almost All

Abstract. Multi-rotor wind turbines (MRWTs) have been suggested in the literature as a solution to achieving wind turbine systems with capacities greater than 10 MW. MRWTs utilize a large number of small rotors connected to one support structure instead of one large rotor with the aim of circumventing the square cube law. Potential benefits of MRWTs include cost and material savings, standardization of parts, increased control possibilities, and improved logistics for assembly and maintenance. Almost all previous work has focused on mechanical and aerodynamic feasibility, with almost no attention being paid to the electrical systems. In this research eight different topologies of the electrical collection network for MRWTs are analysed to assess which are the most economically and practically viable options. AC and DC collection networks are presented in radial, star, cluster and DC series topologies. Mass, capital cost and losses are estimated based on scaling relationships from the academic literature and up-to-date commercial data. The focus of this study is the assessment of the type of electrical collector topology, so component type and voltage level are kept consistent between topology designs in order to facilitate a fair comparison. Topologies are compared in terms of four main criteria: capital cost, cost effectiveness, total mass and reliability. A comparison table is presented to summarize the findings of the research in a convenient way. It is found that the most cost-effective solutions are the AC radial and AC star topologies, with the least cost-effective being the DC series–parallel and DC cluster topologies. This is due to the high cost of DC–DC converters and DC switchgear along with the lower efficiency of DC converters. Radial designs perform best in terms of efficiency and annual energy capture. DC systems achieve a slightly lower nacelle mass compared to their equivalent AC systems. DC topologies are generally found to be more expensive when compared to their AC counterparts due to the high cost of DC–DC converters and DC switchgear. Star topologies are considered to have the best reliability due to having no shared equipment. The most suitable collection topology for MRWTs is shown to be of the star type, in which each turbine is connected to the step-up transformer via its own cable.

scholarly journals Comparison of electrical collection topologies for multi-rotor wind turbines

2020 ◽  
Author(s):  
Paul Pirrie ◽  
David Campos-Gaona ◽  
Olimpo Anaya-Lara
Keyword(s):  
Wind Turbines ◽  
Capital Cost ◽  
Voltage Level ◽  
Academic Literature ◽  
Electrical Systems ◽  
Component Type ◽  
Fair Comparison ◽  
Potential Benefits ◽  
Almost All ◽  
Large Rotor

Abstract. Multi-rotor wind turbines (MRWT) have been suggested in literature as a solution to achieving wind turbine systems with capacities greater than 10 MW. MWRT's utilise a large number of small rotors connected to one support structure instead of one large rotor, with the aim of circumventing the square cube law. Potential benefits of MRWT's include cost and material savings, standardisation of parts, increased control possibilities and improved logistics for assembly and maintenance. Almost all previous work has focused on mechanical and aerodynamic feasibility, with almost no attention being paid to the electrical systems. In this research eight different topologies of the electrical collection network for MRWT's are analysed to assess which are the most economically and practically viable options. AC and DC collection networks are presented in radial, star, cluster and DC series topologies. Mass, capital cost and losses are estimated based on scaling relationships from academic literature and up to date commercial data. The focus of this study is the assessment of the type of electrical collector topology so component type and voltage level are kept consistent between topology designs in order to facilitate a fair comparison. Topologies are compared in terms of four main criteria; capital cost, cost effectiveness, total mass, and reliability. The most suitable collection topology for MRWT's is shown to be of the star type, in which each turbine is connected to the step up transformer via its own cable. DC topologies are generally found to be more expensive when compared to their AC counterparts due to the high cost of DC-DC converters and DC switchgear.

Teletinnitus Program at the VA Gulf Coast Veterans Health Care System

2014 ◽  
Vol 4 (1) ◽  
pp. 23-29
Author(s):  
Constance Hilory Tomberlin
Keyword(s):  
Health Care ◽  
Patient Satisfaction ◽  
Patient Care ◽  
Health Care System ◽  
Gulf Coast ◽  
New Technology ◽  
Cost Effective ◽  
Veterans Health ◽  
Potential Benefits ◽  
Care System

There are a multitude of reasons that a teletinnitus program can be beneficial, not only to the patients, but also within the hospital and audiology department. The ability to use technology for the purpose of tinnitus management allows for improved appointment access for all patients, especially those who live at a distance, has been shown to be more cost effective when the patients travel is otherwise monetarily compensated, and allows for multiple patient's to be seen in the same time slots, allowing for greater access to the clinic for the patients wishing to be seen in-house. There is also the patient's excitement in being part of a new technology-based program. The Gulf Coast Veterans Health Care System (GCVHCS) saw the potential benefits of incorporating a teletinnitus program and began implementation in 2013. There were a few hurdles to work through during the beginning organizational process and the initial execution of the program. Since the establishment of the Teletinnitus program, the GCVHCS has seen an enhancement in patient care, reduction in travel compensation, improvement in clinic utilization, clinic availability, the genuine excitement of the use of a new healthcare media amongst staff and patients, and overall patient satisfaction.

Application of Natural Dye Obtained from Sweet Indrajao on Fabrics

2020 ◽  
Vol 6 (3) ◽  
pp. 180-191
Author(s):  
Kavitha Chandrasekaran
Keyword(s):  
Potassium Dichromate ◽  
Bacterial Pathogens ◽  
Ultrasonic Method ◽  
Ferrous Sulphate ◽  
Fine Powder ◽  
Cost Effective ◽  
Metal Salts ◽  
Cow Dung ◽  
Long Run ◽  
Almost All

Background:: In the long run, synthetic tints were found to be harmful to the chemicals. As a result natural tints have come to be used for their many intrinsic values. The main reason being, then availability of local plants as the main source of natural colorants. Their easy availability in the country being zero cost – effective and planted for other purposes are the main reasons for utilizing them as natural tints. Almost all the parts of the plants, namely stem, leaves, fruits, seeds, barks etc. are used for extracting natural colour. In addition, they are antimicrobial antifungal, insect – repellant deodorant, disinfectant having medicinal values. Methods:: Sweet Indrajao leaves were cleaned by washing with water and dried under direct sunlight and ground as fine powder. A fine strainer was used to remove the wastages. After all these processes, 1-kilogram leaves weighed 318 grams. Then, it is put in 75% ethanol 25% water and heated in a breaker which in kept over a water bath for 2 hours. After this, the contents were filtered and kept in a separate beaker. Bleached fleece draperies stained with stain extract were made to become wet and put into different stain baths which contain the required amount of stain extract and water. Acetic acid was added to it after 20 minutes. The fleece drapery was stained for about one hour at 60oC. The draperies thus stained were removed, squeezed, and put to treatment with metal salts without washing. Different metal salts were used for the treatment using 3% of any one of the chemical mordants like alum, stannous chloride, potassium dichromate, ferrous sulphate, nickel sulphate, copper sulphate and natural mordants such as myrobolan, turmeric, cow dung, Banana sap juice at 60oC for 30 minutes with MLR of 1:30. The stained draperies were washed repeatedly in all the three methods in water and dried in air. At last, the stained draperies were put to soap with soap solution at 60oC for 10 minutes. The draperies were repeatedly washed in water and dried under the sun. Results:: Sweet Indrajao leaves discharged colour easily in alcoholic water. The fleece draperies were stained with chemical and natural mordants. It was observed that the stain uptake was found to be good in post-mordanting method. Ultrasonication has clearly improved the stainability of the draperies at pH 3 and 3.5 values. The pH decreases the stain ability under both Conventional and Ultrasonic conditions. The colour strength increases with an increase in staining temperature in both cases of US and CH methods. Conclusion:: Sweet Indrajao.L has been found to have good ultrasonic potential as a stain plant. The stain uptake as well as the fastness properties of the fleece drapery were found to enhance when metal mordant was used in conjugation with ultra-sonication for the extract of Sweet Indrajao. It was also found that the enhancement of staining ability was better without mordant draperies. The dye extract showed good antibacterial activity against the three bacterial pathogens. Among the three bacterial pathogens, dye extract showed more effective against Escherichia coli pathogens and dye extract showed more effective against Aspergillus pathogens. Hence, the ultrasonic method of drapery staining may be appropriate and beneficial for society at large in future.

scholarly journals Cost-Effective Condition Monitoring for Wind Turbines

2010 ◽  
Vol 57 (1) ◽  
pp. 263-271 ◽  
Author(s):  
Wenxian Yang ◽  
P.J. Tavner ◽  
C.J. Crabtree ◽  
M. Wilkinson
Keyword(s):  
Condition Monitoring ◽  
Wind Turbines ◽  
Cost Effective ◽  
Effective Condition

scholarly journals Heat Exchanger Network Retrofit of an Oleochemical Plant through a Cost and Energy Efficiency Approach

2021 ◽  
Vol 5 (2) ◽  
pp. 17
Author(s):  
Valli Trisha ◽  
Kai Seng Koh ◽  
Lik Yin Ng ◽  
Vui Soon Chok
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Cost Effective ◽  
Capital Cost ◽  
Global Market ◽  
Annual Saving ◽  
Heat Exchanger Network ◽  
First Case ◽  
Payback Time ◽  
Better Than

Limited research of heat integration has been conducted in the oleochemical field. This paper attempts to evaluate the performance of an existing heat exchanger network (HEN) of an oleochemical plant at 600 tonnes per day (TPD) in Malaysia, in which the emphases are placed on the annual saving and reduction in energy consumption. Using commercial HEN numerical software, ASPEN Energy Analyzer v10.0, it was found that the performance of the current HEN in place is excellent, saving over 80% in annual costs and reducing energy consumption by 1,882,711 gigajoule per year (GJ/year). Further analysis of the performance of the HEN was performed to identify the potential optimisation of untapped heating/cooling process streams. Two cases, which are the most cost-effective and energy efficient, were proposed with positive results. However, the second case performed better than the first case, at a lower payback time (0.83 year) and higher annual savings (0.20 million USD/year) with the addition of one heat exchanger at a capital cost of USD 134,620. The first case had a higher payback time (4.64 years), a lower annual saving (0.05 million USD/year) and three additional heaters at a capital cost of USD 193,480. This research has provided a new insight into the oleochemical industry in which retrofitting the HEN can further reduce energy consumption, which in return will reduce the overall production cost of oleochemical commodities. This is particularly crucial in making the product more competitive in its pricing in the global market.

Development and Field Testing of an Inclined Flanged Compact Diffuser for a Micro Wind Turbine

2014 ◽  
Author(s):  
Sandip Kale ◽  
S. N. Sapali
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Wind Turbines ◽  
Energy Production ◽  
Cost Effective ◽  
Field Testing ◽  
International Electrotechnical Commission ◽  
Average Wind Speed ◽  
Average Wind ◽  
Power Curves

Micro wind turbines installed in various applications, experience average wind speed for most of the time during operations. Power produced by the wind turbine is proportional to the cubic power of the wind velocity and a small increase in wind velocity results increases power output significantly. The approach wind velocity can be increased by covering traditional wind turbine with a diffuser. Researchers are continuously working to develop a compact, lightweight, cost effective and feasible diffuser for wind turbines. The present work carried out to develop a diffuser with these stated objectives. A compact, lightweight inclined flanged diffuser developed for a micro wind turbine. Bare micro wind turbine and wind turbine covered with developed efficient inclined flanged diffuser tested in the field as per International Electrotechnical Commission (IEC) standards and results presented in the form of power curves. The prediction of annual energy production for both wind turbines determined as per IEC standards.

Laser-Based Measurement of Over Dimensional Freight Rail Shipments

2012 ◽  
Author(s):  
Bryan W. Schlake ◽  
Brian S. Daniel ◽  
Ron Voorheis
Keyword(s):  
Measurement System ◽  
Human Error ◽  
Cost Effective ◽  
Measuring System ◽  
Prototype System ◽  
Reference Target ◽  
Potential Benefits ◽  
Multiple Measurements ◽  
Current Measuring ◽  
Time Required

In pursuit of improved safety, Norfolk Southern Corp. (NS) has partnered with Amberg Technologies to explore the potential benefits of a laser-based measurement system for measuring over dimensional freight rail shipments. Shipments that do not fall within a standard geometric envelope, denoted as Plate B in the Association of American Railroads (AAR) Open Top Loading Rules [1], are considered to be over dimensional, or High-Wide Loads (HWLs). Extending beyond the limits of the Plate B diagram, these loads are not permitted in unrestricted interchange service. Instead, they must be measured both at points of origin and at interchange points. For US Class I Railroads, the de facto method for measuring HWLs requires mechanical personnel to either climb on the equipment or use a ladder and physically measure the overall height and width of the load. Using a tape measure, plumb line, and 6-foot level, car inspectors, or carmen, must often make multiple measurements to determine the height or width of a critical point on the load. The summation of these measurements can be subject to mathematical human error. In addition to the inherent limitations with regards to accuracy and efficiency, this method of measurement presents considerable safety challenges. The objective of the project was to develop a portable, cost-effective and accurate measurement system to improve the day-to-day operational process of measuring HWLs and reduce human exposure to railyard hazards. Norfolk Southern worked closely with Amberg Technologies to provide a clear overview of the current measuring methods, requirements, challenges and risks associated with HWLs. Amberg then developed a prototype system (with patent pending) and successful tests have been completed at both a point of origin for NS shipments and at a location where HWLs are received at interchange. The measuring system consists of a tripod mounted laser, a specially designed track reference target (TRT) and software designed specifically for HWL measurements. The system allows car inspectors to take measurements from a safe, strategic location away from the car. As a result, this system eliminates the need to climb on the equipment or a ladder and greatly reduces the amount of time spent on and around live tracks. In addition, initial tests indicate that this technology reduces the labor time required to measure HWLs by as much as one half while improving measurement accuracy. These tests have demonstrated that a laser-based system has the potential to greatly improve the safety, efficiency and accuracy associated with measuring HWLs.

Physical Exercise and Yoga: as an alternative approach towards COVID-19 management

2021 ◽  
Vol 07 ◽  
Author(s):  
Saurabh Kumar ◽  
Sakshi Sudha ◽  
Madhu Chopra ◽  
Famida Khan ◽  
Kanupriya Sharma
Keyword(s):  
Physical Exercise ◽  
Literature Search ◽  
Viral Infections ◽  
Cost Effective ◽  
Mental Wellbeing ◽  
World Population ◽  
Cd8 Cells ◽  
Global Pandemic ◽  
Potential Benefits ◽  
Novel Coronavirus

Background: Novel Coronavirus (COVID-19), a highly contagious ssRNA +Ve sense virus that emerged in late 2019, has created a global panic. With no effective therapy available, the virus has significantly affected the world population causing millions of death. Therefore, it is the utmost need to look towards all the possible strategies to benefit the community. Objectives: In view of the current global pandemic, we tried to discuss the potential benefits of two cost-effective alternative approaches, i.e., physical exercise and yoga. Method: The editorial is based on a literature search available on PubMed, Google Scholar, and WHO portal. Search terminologies include “yoga”, “physical exercise”, “COVID-19”, “viral infections”, and a combination of these words. Results: A literature search defines yoga and physical exercise efficacy in different viral diseases, including HIV, influenza, and HSV. It ameliorates the quality of life (QoL) by improving both the physical and mental wellbeing of an individual. This is mainly done by promoting the better functioning of the immune system (increases CD4+ and CD8+ cells and reduces pro-inflammatory response). Conclusions: Regular involvement of these activities in day-to-day life may limit latent virus reactivations and reduce infection chances.

scholarly journals Relative and quantitative rhizosphere microbiome profiling result in distinct abundance patterns

2021 ◽  
Author(s):  
Hamed Azarbad ◽  
Julien Tremblay ◽  
Luke D. Bainard ◽  
Etienne Yergeau
Keyword(s):  
Water Stress ◽  
Relative Abundance ◽  
Its Region ◽  
Cost Effective ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Real Time Quantitative Pcr ◽  
Rhizosphere Microbiome ◽  
History Of ◽  
Almost All

AbstractNext-generation sequencing is recognized as one of the most popular and cost-effective way of characterizing microbiome in multiple samples. However, most of the currently available amplicon sequencing approaches are inherently limited, as they are often presented based on the relative abundance of microbial taxa, which may not fully represent actual microbiome profiles. Here, we combined amplicon sequencing (16S rRNA gene for bacteria and ITS region for fungi) with real-time quantitative PCR (qPCR) to characterize the rhizosphere microbiome of wheat. We show that the increase in relative abundance of major microbial phyla does not necessarily result in an increase in abundance. One striking observation when comparing relative and quantitative abundances was a substantial increase in the abundance of almost all phyla associated with the rhizosphere of plants grown in soil with no history of water stress as compared with the rhizosphere of plants growing in soil with a history of water stress, which was in contradiction with the trends observed in the relative abundance data. Our results suggest that the estimated absolute abundance approach gives a different perspective than the relative abundance approach, providing complementary information that helps to better understand the rhizosphere microbiome.

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