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1	Photovoltaic Electrolysis Propulsion System January 2015 (has links) abstract: CubeSats are a newly emerging, low-cost, rapid development platform for space exploration research. They are small spacecraft with a mass and volume of up to 12 kg and 12,000 cm3, respectively. To date, CubeSats have only been flown in Low Earth Orbit (LEO), though a large number are currently being designed to be dropped off by a mother ship on Earth escape trajectories intended for Lunar and Martian flyby missions. Advancements in propulsion technologies now enable these spacecraft to achieve capture orbits around the moon and Mars, providing a wealth of scientific data at low-cost. However, the mass, volume and launch constraints of CubeSats severely limit viable propulsion options. We present an innovative propulsion solution using energy generated by onboard photovoltaic panels to electrolyze water, thus producing combustible hydrogen and oxygen for low-thrust applications. Water has a high storage density allowing for sufficient fuel within volume constraints. Its high enthalpy of formation provides more fuel that translates into increased ∆V and vastly reduced risk for the launch vehicle. This innovative technology poses significant challenges including the design and operation of electrolyzers at ultra-cold temperatures, the efficient separation of the resultant hydrogen and oxygen gases from liquid water in a microgravity environment, as well as the effective utilization of thrust to produce desired trajectories. Analysis of the gas combustion and flow through the nozzle using both theoretical equations and finite-volume CFD modeling suggests an expected specific impulse of 360 s. Preliminary results from AGI's Satellite Toolkit (STK) indicate that the ΔV produced by the system for an 8kg CubeSat with 6kg of propellant in a LEO orbit (370 km altitude) is sufficient for an earth escape trajectory, lunar capture orbit or even a Mars capture orbit. These results suggest a promising pathway for an in-depth study supported by laboratory experiments to characterize the strengths and weaknesses of the proposed concept. / Dissertation/Thesis / Masters Thesis Aerospace Engineering 2015 Aerospace engineering Physical chemistry CubeSat Electrolysis Freezing Point Depression Interplanetary PEM Electrolyzer Propulsion
2	Utilization of waste heat from hydrogen production : A case study on the Botnia Link H2 Project in Luleå, Sweden Miljanovic, Andrea, Jonsson, Fredrik January 2022 (has links) The global hydrogen demand is steadily increasing, and one way of accelerating the green hydrogen supply is to stimulate the green hydrogen economy. Utilization of waste heat from hydrogen production can increase the profitability of produced green hydrogen. Therefore, the aim of this study is to propose a system for integration of waste heat on the district heating (DH) network in Luleå, Sweden. Furthermore, an economic evaluation of the proposed system was conducted. In this study, the system was developed and investigated for two cases i.e. for a PEM and alkaline electrolyzer with an installed capacity of 100 MW. A large-scale heat pump and a heat exchanger were further added to the system to integrate the waste heat on the DH-network, while simultaneously providing cooling to the electrolyzer stack. The system was modelled for static conditions in the software MATLAB, with retrieved hourly DH data from Luleå Energi. The results showed that 203 060 MWhth can be extracted from the PEM electrolyzer with a waste heat temperature of 79 oC, while 171 770 MWhth can be integrated on the DH network annually. For the alkaline electrolyzer, 310 630 MWhth can be extracted at a waste heat temperature of 80 oC, while 226 220 MWhth can be integrated on the DH annually. The overall system efficiency is 94.7 % and 88.4 % for PEM and alkaline connected systems, respectively. Furthermore, the Levelized Cost of Heat (LCOH) is 0.218 SEK/kWhth and 0.23 SEK/kWhth for a PEM and alkaline connected system, respectively. For future scenarios with fourth generation of DH-networks, it is predicted that the LCOH can reach 0.018 SEK/kWth for a PEM electrolyzer system, and 0.017 SEK/kWth for an alkaline electrolyzer system. One conclusion that can be drawn from this study is that the utilized heat from the proposed system is price competitive in comparison with other thermal energy sources. PEM electrolyzer alkaline electrolyzer waste heat district heating LCOH Energy Systems Energisystem Engineering and Technology Teknik och teknologier
3	Power-to-X-to-Power in Combined Cycle Power Plants : A Techno-Economic Feasibility Study Engstam, Linus January 2021 (has links) To support the largescale integration of renewables in electricity grids, powertoXtopower (P2X2P) systems have been proposed. These systems serve to increase the flexibility of thermal power plants while potentially providing both economic and environmental benefits by allowing power from the plant to be redirected into an electrolyzer and converted to a gaseous energy carrier. In this study, the feasibility of a P2X2P system consisting of a combined cycle gas turbine (CCGT) power plant coupled with a PEM electrolyzer in the Italian power sector has been investigated. A dynamic technoeconomic model has been developed for both hydrogen and ammoniabased systems together with a profit maximizing dispatch strategy for operation in both day-ahead and balancing electricity markets. As a part of this, a PEM electrolyzer model was also developed and validated against experimental data. Notable technical improvements were observed as a consequence of the implementation of a P2X2P system in the form of avoided shutdowns and a more even power output. However, any economic and environmental benefits of such improvements were not observed as the addition of the P2X2P system led to a reduction in net present value as well as higher specific emissions of carbon dioxide. When the gaseous energy carrier was utilized as fuel in the CCGT, similar technical performances were achieved by the hydrogenbased and ammoniabased systems. Due to the increased investment cost demanded by the ammonia production process the hydrogenbased system thus seems most suitable for this setup. / För att möjliggöra en storskalig utbyggnad av förnyelsebar energi har powertoXtopowersystem (P2X2P) föreslagits som en potentiell lösning. Genom att omdirigera electricitet från kraftverket till en elektrolysator och därmed omvandla denna till vätgas kan dessa system förbättra den tekniska flexibiliten hos värmekraftverk samtidigt som de har potential att medföra både ekonomiska och miljömässiga fördelar. Detta examensarbete har undersökt den teknoekonomiska potentialen hos ett P2X2Psystem bestående av ett gaskombikraftverk i anslutning till en elektrolysator i det italienska kraftnätet. En dynamisk, teknoekonomisk modell av både vätgas och ammoniakbaserade P2X2Psystem samt en vinstmaximerande kontrollstrategi har utvecklats. En modell över en PEMelektrolysator har även utvecklats och validerats gentemot experimentella data. Införandet av ett P2X2Psystem till kraftverket påvisade en teknisk förbättringspotential genom ett minskat antal uppstarter samt en mer jämn uteffekt. Huruvida denna tekniska förbättring också medför ekonomisk and miljömässig förbättring eller ej kvarstår att påvisa. Detta då nuvärdet minskade samtidigt som koldioxidutsläppen per producerad kilowatttimme ökade vid införandet av P2X2Psystemet. Då den producerade energibäraren, i form av vätgas eller ammoniak, enbart användes för att ersätta fossilgas som bränsle i kraftverket påvisades marginell skillnad i presetanda mellan de två systemen. De större kostnaderna som medförs av ett ammoniakbaserat system pekar därför på att ett vätgasbaserat system vore att föredra under sådana förutsättningar. PowertoXtopower Hydrogen Ammonia Combined cycle gas turbines PEM electrolyzer Technoeconomic analysis PowertoXtopower Vätgas Ammoniak Gasturbiner PEM elektrolysator Teknoekonomisk analys Engineering and Technology Teknik och teknologier
4	Hydrogen Production and Storage Optimization based on Technical and Financial Conditions : A study of hydrogen strategies focusing on demand and integration of wind power. / Optimering av vätgasproduktion och lagring utifrån tekniska och ekonomiska förutsättningar : En studie av vätgasstrategier med fokus på efterfrågan och integration av vindkraft. Langels, Hanna, Syrjä, Oskar January 2021 (has links) There has recently been an increased interest in hydrogen, both as a solution for seasonal energy storage but also for implementations in various industries and as fuel for vehicles. The transition to a society less dependent on fossil fuels highlights the need for new solutions where hydrogen is predicted to play a key role. This project aims to investigate technical and economic outcomes of different strategies for production and storage of hydrogen based on hydrogen demand and source of electricity. This is done by simulating the operation of different systems over a year, mapping the storage level, the source of electricity, and calculating the levelized cost of hydrogen (LCOH). The study examines two main cases. The first case is a system integrated with offshore wind power for production of hydrogen to fuel the operations in the industrial port Gävle Hamn. The second case examines a system for independent refueling stations where two locations with different electricity prices and traffic flows are analyzed. Factors such as demand, electricity prices, and component costs are investigated through simulating cases as well as a sensitivity analysis. Future potential sources of income are also analyzed and discussed. The results show that using an alkaline electrolyzer (AEL) achieves the lowest LCOH while PEM electrolyzer is more flexible in its operation which enables the system to utilize more electricity from the offshore wind power. When the cost of wind electricity exceeds the average electricity price on the grid, a higher share of wind electricity relative to electricity from the grid being utilized in the production results in a higher LCOH. The optimal design of the storage depends on the demand, where using vessels above ground is the most beneficial option for smaller systems and larger systems benefit financially from using a lined rock cavern (LRC). Hence, the optimal design of a system depends on the demand, electricity source, and ultimately on the purpose of the system. The results show great potential for future implementation of hydrogen systems integrated with wind power. Considering the increased share of wind electricity in the energy system and the expected growth of the hydrogen market, these are results worth acknowledging in future projects. Hydrogen hydrogen energy system hydrogen production hydrogen storage large-scale storage underground storage vessels LRC hydrogen application hydrogen strategies hydrogen transition offshore wind energy electricity grid electricity price volatile electricity prices renewable energy hydrogen refueling station hydrogen port green hydrogen hydrogen trucks hydrogen forklifts fuel cells electrolysis alkaline electrolyzer PEM electrolyzer levelized cost of hydrogen LCOH Vätgas vätgassystem vätgasproduktion vätgaslagring storskalig vätgaslagring bergrum vätgasapplikationer vätgasstrategi vätgasomställning grön omställning havsbaserad vindkraft volatila elpriser elnätet förnybar energi vätgastankstation vätgasmack vätgashamn grön vätgas vätgaslastbilar vätgastruckar bränsleceller elektrolys alkalisk elektrolysör PEM elektrolysör Elektroteknik och elektronik

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