Search for dissertations about: "Energy level width"

Showing result 1 - 5 of 46 swedish dissertations containing the words Energy level width.

2. 1. Modulation, efficiency and lifetime of two-level and multilevel converters for a hydropower application

   Author : Chengjun Tang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pumped-storage hydropower; pulse width modulation; losses; modular multilevel converter; efficiency; variable speed; converter; lifetime; space vector modulation; thermal modelling; neutral point clamped converter;

   Abstract : Along with the integration of the renewable energy in the electrical grid, the pumped-storage hydropower has gained more and more attention due to its fast response and energy storage ability. To have a higher overall efficiency and more flexibility of the system, variable speed is preferred in the operation of the pumped-storage hydropower applications. READ MORE

4. 2. Grid Connected Three-Level Converters : Studies for Wave Energy Conversion

   Author : Remya Krishna; Mats Leijon; Karin Thorburn; Uppsala universitet; []
   Keywords : Wave energy; power converters; control strategies; grid connection; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

   Abstract : This thesis presents an electrical system analysis of a wave energy converter (WEC) for the objective of grid connection. To transfer the enormous amount of power from waves to the load centers, efficient power electronic systems are essential. READ MORE

5. 3. Modelling District Heating Network Costs

   Author : Luis Sánchez-García; Urban Persson; Helge Averfalk; Erik Möllerström; Marcus Thern; Magnus Åberg; Sweden Lund Lund University; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; District Heating; Pipe network; Cost analysis; Distribution Capital Cost; Effective Width; Plot Ratio; Heat Density; GIS; Smart Cities and Communities; Smarta städer och samhällen;

   Abstract : The solution of the undergoing climate and energy crises requires a radical transformation of the energy system, in which sustainability, no carbon emissions and energy efficiency ought to play a paramount role. This revolution should extend to all areas of the energy system, including the space heating and cooling sector, which accounts for a third of the European final energy demand and, in the European continent, it is still mostly supplied by fossil fuels. READ MORE

6. 4. Lithium-ion batteries for off-grid PV-systems

   Author : Fabian Benavente; Göran Lindbergh; Anders Olof Lundblad; Saul Cabrera; Daniel Abraham; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lithium-ion batteries; aging; partial cycles; DVA; EIS; NCA; stationary energy systems; PV systems; rural electrification.; Chemical Engineering; Kemiteknik;

   Abstract : This thesis provides a comprehensive and detailed analysis on the effect ofthe battery operation strategy on the lifetime of commercial lithium-ionbatteries and on the economics of off-grid photovoltaic (PV)-batterysystems.Lithium-ion batteries play a key role in the transition to a fossil-freesociety. READ MORE

7. 5. Vertical Display Cabinets in Supermarkets - Energy Efficiency and the Influence of Air Flows

   Author : Monica Axell; RISE; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; display cabinet; model; simulation; supermarket; CFD; air curtain; energy; performance; air distribution; display case; infiltration;

   Abstract : This thesis concerns investigations of the performance of vertical refrigerated display cabinets. Such cabinets are in widespread use and account for a considerable proportion of the energy used in shops. The open front is important for the shop-owner, who wants the chilled items in the cabinet to be well exposed and easily accessible. READ MORE