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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nyttomaximering av en solcellsanläggning : En jämförelse mellan ett konventionellt- och ett smart solcellssystem. / Maximizing the utility of a photovoltaic plant

Östling, Erik, Josefsson, Filip January 2018 (has links)
Detta kandidatexamensarbete utvärderar och jämför en befintlig solcellsanläggning med installerat energilager samt en smart växelriktare i Farsta, Stockholm. Jämförelsen ställer denna anläggning mot ett konventionellt solcellssystem med enbart solceller. Studiens syfte är att identifiera mängden egenanvänd solenergi, ta fram optimeringsförslag samt belysa eventuella kostnadsbesparingar. Den smarta växelriktaren har möjliggjort datainsamling via en webbaserad användarportal, portalen loggar och sparar anläggningens energi- och effektdata.   Studien påvisar att systemet inte bidrar med en betydande ökning av egenanvändningen av solenergi, ty batteriets inställningar ofta medför att batteriet är fulladdat under dagens soltimmar. Det smarta systemets mest fördelaktiga funktion är att kapa fastighetens effekttoppar vilket skapar möjlighet till nedsäkring.   Hur stor del av effekttopparna som kan kapas är starkt beroende av batteriets inställningar. Under studien har två olika scenarier testats. Det mest essentiella är att batteriet alltid kan kapa de högsta effekttopparna samtidigt som det aldrig laddas ur helt. Nyttan maximeras när batteriet aktiveras vid förbrukningar över 24 kW. Säkringsanalyserna från studien visar att fastighetens minsta möjliga huvudsäkringar som kan brukas är 35 A, dock rekommenderas nyttjande av huvudsäkringar om 50 A då en säkerhetsmarginal är önskvärd. Den rekommenderade nedsäkringen ger möjlighet att teckna ett billigare elavtal. Slutsatsen är att säkringsabonnemanget TID relativt effektabonnemanget L0,4S ger en kostnadsbesparing om 33 547 kronor per år. / This bachelor thesis is evaluating and comparing an existing photovoltaic system including an energy storage and a smart bidirectional converter in Farsta, Stockholm. This smart system will be compared with a conventional PV plant. The aim of the report is to identify the amount of self-consumed solar energy, give optimizing suggestions and shed light on possible cost savings. The smart converter has given the possibility to collect data from a web-based portal. The portal logs and stores the energy and power data of the system.   The study proves that this smart system does not contribute with an increased amount of self-consumed solar energy, since the battery settings implies a fully charged battery during the day. The most advantageous benefit in the smart system is to cut power peaks, which gives opportunities to use smaller main fuses in the real estate.   The magnitude of the power peaks that can be reduced is depending on the settings of the battery. Two different scenarios have been examined in the study. The most essential is that the battery is always able to cut the highest power peaks without being fully discharged. The maximum utility occurs when the battery is activated when the consumption is higher than 24 kW. Fuse analysis proves that the lowest possible main fuses that could be used in the real estate is 35 A. Though, this study recommends main fuses of 50 A since a safety margin is desired. This gives opportunities to sign a more beneficial electricity contract. Conclusively, the fuse rating contract that can be used is 33 547 SEK cheaper per year than the power rating contract that is used in the real estate today.
2

Utvärdering av förebyggande underhållsstrategi för elektriska flygplan

Alfredsson, Ammar January 2023 (has links)
This thesis focuses on the topic of preventive maintenance for electric aircraft and aims to examine its significance and implementation within the aviation industry. Electric aircraft have become increasingly popular as a sustainable alternative to conventional aircraft, making it crucial to develop effective maintenance strategies to ensure their reliability and performance. To achieve this objective, a comprehensive literature review of existing research and practices in the field of preventive maintenance for electric aircraft is conducted. The study identifies the key components and systems in an electric aircraft that require regular monitoring and maintenance, such as electric motors, batteries, power converters, and control systems. By analyzing the benefits of preventive maintenance, such as reduced downtime, increased component lifespan, and decreased maintenance costs, various methods, and techniques for implementing preventive maintenance for electric aircraft are presented. This includes the use of condition monitoring systems, sensors, and data-driven analysis to monitor and predict the health of components and anticipate any faults or deviations in advance. To explore the challenges of preventive maintenance for electric aircraft, aspects such as data management, cooling, and electromagnetic compatibility are also discussed. Furthermore, the need for training and skill development for maintenance personnel to effectively carry out preventive maintenance activities for electric aircraft is explored. By compiling and analyzing the available information, this thesis provides a comprehensive overview of preventive maintenance for electric aircraft and its significance in ensuring reliability, performance, and sustainability within the aviation industry. The findings can be valuable to airlines, maintenance organizations, and researchers interested in implementing effective maintenance strategies for electric aircraft and contributing to the continued development of sustainable aviation. The literature review showed that the use of preventive maintenance strategy for electric aircraft is well-founded and supported by research and experiences from various industries. The implementation of IoT and fault diagnostic techniques can enhance the maintenance process and increase the reliability of electric aircraft by identifying and addressing potential faults at an early stage. These findings provide valuable insights and guidelines for the aviation industry in developing and optimizing their maintenance strategies for electric aircraft.
3

Battery Driven Embedded System for Indoor Localization of Pneumatic Tools

Hjort, Kajsa January 2020 (has links)
As the rapid progress in technology changes our daily life, it also changes how the Industry works. The new developments enable technologies such as the Internet of Moving Things (IoMT), and through these technologies, new challenges arise. IoMT adds one more vital issue, localization, to be solved in comparison to the Internet of Things (IoT). To enable IoMT in the manufacturing industry, there are still problems that need to be overcome. Critical statements such as power consumption, price, accuracy, data management, and size. In this thesis, an evaluation of a new sensor system for an air pneumatic grinder is conducted. The features of the sensor system are to report data from the grinder to the cloud and to localize the position of the grinder. The focus was to optimize the localization algorithm and power consumption of the system. The localization of the grinder was conducted with a new and improved algorithm, Ring Error Difference System (REDS), introduced in this thesis. The new algorithm increased the previous known iRingLA accuracy from 2.91 m to 2.33 m for Bluetooth Low Energy (BLE) and from 3.99 m to 2.84 for Wi-Fi, according to the experiments performed. The final system was able to estimate the operation runtime with an error of 24 s for an operational runtime of 905 s. The operational lifetime of the system was 242 h and 45 h, respectively, for BLE and Wi-Fi. An optimized software was introduced to decrease power consumption. The optimized version was estimated to have an operational lifetime of 1540 h for BLE, which did not reach the wanted lifetime of 3000 h set by Atlas Copco. Hence, I conclude that the hardware, Wemos ESP32, used in the thesis, is not feasible for this solution. Simpler hardware, than the Wemos ESP32, should be used to be able to reach the goal of 3000 h. / De stora framstegen inom dagens teknik förvandlar inte bara vårt dagliga liv det förändrar också tekniken inom industrin. Den nya tekniken möjliggör framsteg så som Internet of Moving Things (IOMT), vilket leder till nya utmaningar. IoMT jämfört med Internet of Things (IoT) lägger till ytterligare utmaningar att lösa så som lokalisering. För att kunna använda IoMT inom tillverkningsindustrin måste ett flertal problem hanteras så som strömförbrukning, pris och noggrannhet på lokaliseringen, datahantering och storlek på systemet. I denna masteruppsatts gör jag en utvärdering av ett nytt sensorsystem för luftdrivna slipmaskiner. Detta sensorsystem rapporterar data från slipmaskinen till molnet och rapporterar positionen av utrustningen. Fokuset på uppsatsen var att optimera lokaliseringsalgoritmen och minska strömförbrukningen för systemet. Lokaliseringen av slipmaskinen gjordes med en ny och förbättrad algoritm, Ring Error Difference System (REDS), som jag introducerar i avhandlingen. Algoritmen förbättrade den tidigare kända RSSI-baserade iRingLA från 2,91 m till 2,33 m med Bluetooth Low Energy (BLE) och från 3,99 m till 2,84 m för Wi-Fi. Det slutliga systemet kunde uppskatta drifttiden med en avvikelse på 24 s av den verkliga drifttiden, 905 s. Systemets operativa livslängd var 242 timmar och 45 timmar för BLE respektive Wi-Fi. Dessutom infördes en optimerad programvara för att minska strömförbrukningen. Den optimerade versionen beräknades ha en livslängd på 1540 timmar för BLE, vilket inte når den önskade livslängden på 3000 timmar satt av Atlas Copco. Ifrån mitt arbete drar jag slutsatsen att hårdvaran som används i uppsatsen, inte kan användas i en slutlig produkt. En enklare hårdvara än Wemos ESP32 bör användas för att kunna nå målet på 3000 timmar.

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