Blar i NTNU Open på forfatter "Wilhelmsen, Øivind"
-
Electrodialysis in Hydrometallurgical Processes
Zimmermann, Pauline; Tekinalp, Önder; Deng, Liyuan; Forsberg, Kerstin; Wilhelmsen, Øivind; Burheim, Odne Stokke (The Minerals, Metals & Materials Series;, Chapter; Peer reviewed, 2020)Electrodialysis (ED) is an ionic exchange membrane process for separation of different components and species. In desalination, a large part of the energy is used to sustain a concentration difference between the solutions, ... -
Energy efficient design of membrane processes by use of entropy production minimization
Magnanelli, Elisa; Wilhelmsen, Øivind; Johannessen, Eivind; Kjelstrup, Signe (Journal article; Peer reviewed, 2018)To minimize entropy production means to reduce the lost work in a process, and to optimize the use of energy resources. Due to the need for re-compression, membrane units for separation of CO2 from natural gas require large ... -
Enhancing Palladium Recovery Rates in Industrial Residual Solutions through Electrodialysis
Zimmermann, Pauline; Tekinalp, Önder; Wilhelmsen, Øivind; Deng, Liyuan; Burheim, Odne Stokke (Peer reviewed; Journal article, 2023)Palladium is a vital commodity in the industry. To guarantee a stable supply in the future, it is imperative to adopt more effective recycling practices. In this proof-of-concept study, we explore the potential of ... -
Equation of state and force fields for Feynman-Hibbs-corrected Mie fluids. II. Application to mixtures of helium, neon, hydrogen and deuterium
Aasen, Ailo; Hammer, Morten; Müller, Erich; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)We extend the statistical associating fluid theory of quantum corrected Mie potentials (SAFT-VRQ Mie), previously developed for pure fluids [Aasen et al., J. Chem. Phys. 151, 064508 (2019)], to fluid mixtures. In this ... -
Equation of state and force fields for Feynman–Hibbs-corrected Mie fluids. I.Application to pure helium, neon, hydrogen, and deuterium
Aasen, Ailo; Hammer, Morten; Ervik, Åsmund; Müller, Erich A.; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2019)We present a perturbation theory that combines the use of a third-order Barker–Henderson expansion of the Helmholtz energy with Miepotentials that include first- (Mie-FH1) and second-order (Mie-FH2) Feynman–Hibbs quantum ... -
Equation of state for confined fluids
Bråten, Vilde; Zhang, Daniel Tianhou; Hammer, Morten; Aasen, Ailo; Schnell, Sondre Kvalvåg; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2022)Fluids confined in small volumes behave differently than fluids in bulk systems. For bulk systems, a compact summary of the system's thermodynamic properties is provided by equations of state. However, there is currently ... -
Equilibrium and Nonequilibrium Thermodynamics of Planar and Curved Interfaces
Wilhelmsen, Øivind (Doctoral thesis at NTNU;2015:301, Doctoral thesis, 2015)Interfaces can be found everywhere and their properties are of major importance to a wide variety of processes, ranging from DNA replication to weather forecasts. This work is a fundamental study of systems with planar ... -
Exploring the potential for waste heat recovery during metal casting With thermoelectric generators: On-site experiments and mathematical modelling
Børset, Marit Takla; Wilhelmsen, Øivind; Kjelstrup, Signe; Burheim, Odne Stokke (Journal article; Peer reviewed, 2016)Thermoelectric power generators are scalable and simple systems for recovering waste-heat disposed by the industry. We combine on-site measurements and a mathematical model to study the potential for power generation with ... -
A flexible and robust modelling framework for multi-stream heat exchangers
Skaugen, Geir; Kolsaker, Kjell; Walnum, Harald Taxt; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2013)Heat exchangers are important units in most industrial processes. They involve physical phenomena such as condensation and evaporation including several boiling regimes. Different types of heat exchangers constructed for ... -
“Fluid transport through nanoporous media in the presence of phase transitions
Rauter, Michael Tobias (Doctoral theses at NTNU;2022:268, Doctoral thesis, 2022)Clean potable water is among the most precious commodities in the world. Even though water is not sparse on the planet’s surface, it is not sufficiently accessible for about 4 billion people, who are experiencing serious ... -
Forbedring av perturbasjonsteori for Lennard-Jones blandinger med store forskjeller i brønndybder
Price, Sebastian Everard Nordby (Master thesis, 2020)Statistisk assosierende fluid teori (SAFT) har hatt stor suksess i å beskrive assosierende kjede fluider. Disse SAFT-type-tilstandsligningene er som regel skrevet som en sum av Helmholtz fri energi, bestående av et ideelt ... -
Free energy of critical droplets - From the binodal to the spinodal
Aasen, Ailo; Wilhelmsen, Øivind; Hammer, Morten; Reguera, David (Peer reviewed; Journal article, 2023)Arguably, the main challenge of nucleation theory is to accurately evaluate the work of formation of a critical embryo in the new phase, which governs the nucleation rate. In Classical Nucleation Theory (CNT), this work ... -
Fundamental Aspects of Thermodynamics of Small Systems Investigated Through Molecular Simulations and Theoretical Descriptions
Bråten, Vilde (Doctoral theses at NTNU;2022:280, Doctoral thesis, 2022)Systems on the nanoscale can show behaviour that is strikingly different from the behaviour we expect for systems on themacroscopic scale. As a consequence, we can in general not assume that macroscopic theories of matter ... -
Harnessing thermoelectric power from transient heat sources: Waste heat recovery from silicon production
Savani, Isha; Waage, Magnus Heskestad; Børset, Marit Takla; Kjelstrup, Signe; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2017)Thermoelectric generators (TEGs) are compact and robust devices for converting heat into electrical power. In this work, we investigate the response of a bismuth-telluride based TEG to the transient environment of a silicon ... -
Heat to Hydrogen by RED—Reviewing Membranes and Salts for the RED Heat Engine Concept
Zimmermann, Pauline; Solberg, Simon Birger Byremo; Tekinalp, Önder; Lamb, Jacob Joseph; Wilhelmsen, Øivind; Deng, Liyuan; Burheim, Odne Stokke (Peer reviewed; Journal article, 2022)The Reverse electrodialysis heat engine (REDHE) combines a reverse electrodialysis stack for power generation with a thermal regeneration unit to restore the concentration difference of the salt solutions. Current approaches ... -
Heat to Hydrogen by Reverse Electrodialysis—Using a Non-Equilibrium Thermodynamics Model to Evaluate Hydrogen Production Concepts Utilising Waste Heat
Solberg, Simon Birger Byremo; Zimmermann, Pauline; Wilhelmsen, Øivind; Lamb, Jacob Joseph; Bock, Robert; Burheim, Odne Stokke (Peer reviewed; Journal article, 2022)The reverse electrodialysis heat engine (REDHE) is a promising salinity gradient energy technology, capable of producing hydrogen with an input of waste heat at temperatures below 100 °C. A salinity gradient drives water ... -
Heat transport through a solid-solid junction: the interface as an autonomous thermodynamic system
Rurali, R.; Colombo, L.; Cartoixà, X.; Wilhelmsen, Øivind; Trinh, Thuat; Bedeaux, Dick; Kjelstrup, Signe (Journal article; Peer reviewed, 2016-04)We perform computational experiments using nonequilibrium molecular dynamics simulations, showing that the interface between two solid materials can be described as an autonomous thermodynamic system. We verify the local ... -
Ice formation and growth in supercooled water–alcohol mixtures: Theory and experiments with dual fiber sensors
Wahl, Markus Solberg; Aasen, Ailo; Hjelme, Dag Roar; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)Increased knowledge on fluid-solid phase transitions is needed, both when they are undesired and can impair processes operation, and when strict control is required in fields such as food technology, the pharmaceutical ... -
The influence of concentration and temperature on the membrane resistance of ion exchange membranes and the levelised cost of hydrogen from reverse electrodialysis with ammonium bicarbonate
Raka, Yash Dharmendra; Bock, Robert; Karoliussen, Håvard; Wilhelmsen, Øivind; Burheim, Odne Stokke (Peer reviewed; Journal article, 2021)The ohmic resistances of the anion and cation ion-exchange membranes (IEMs) that constitute a reverse electrodialysis system (RED) are of crucial importance for its performance. In this work, we study the influence of ... -
The influence of interfacial transfer and film coupling in the modeling of distillation columns to separate nitrogen and oxygen mixtures
Kingston, Diego; Wilhelmsen, Øivind; Kjelstrup, Signe (Peer reviewed; Journal article, 2020)Coupling between heat and mass transfer occurs across interfaces and in vapor and liquid films. In this work, we present the first rigorous investigation of the role of these physical phenomena in the mathematical modeling ...