Search

Your search keyword '"Ruuskanen, Vesa"' showing total 185 results
Start Over Author "Ruuskanen, Vesa"
185 results on '"Ruuskanen, Vesa"'

1. Benchmarking performance: A round-robin testing for liquid alkaline electrolysis

Author

Appelhaus, Simon, Ritz, Lukas, Pape, Sharon-Virginia, Lohmann-Richters, Felix, Kraglund, Mikkel Rykaer, Jensen, Jens Oluf, Massari, Francesco, Boroomandnia, Mehrdad, Romanò, Maurizio, Albers, Justin, Kubeil, Clemens, Bernäcker, Christian, Lemcke, Michelle Sophie, Menzel, Nadine, Bender, Guido, Chen, Binyu, Holdcroft, Steven, Delmelle, Renaud, Proost, Joris, Hnát, Jaromír, Kauranen, Pertti, Ruuskanen, Vesa, Viinanen, Toni, Müller, Martin, Turek, Thomas, and Shviro, Meital

Published
2024
Full Text
View/download PDF

16. Calculating active power for water electrolyzers in dynamic operation: Simple, isn't it?

Author

Puranen, Pietari, Ruuskanen, Vesa, Järvinen, Lauri, Niemelä, Markku, Kosonen, Antti, Kauranen, Pertti, and Ahola, Jero

Subjects
*GREEN fuels, *WATER electrolysis, *WATER power, *WATER consumption, *ALTERNATING currents
Abstract

Calculating the power consumption of water electrolyzers is a seemingly simple task. Yet, when the supplied current varies periodically in time, careless usage of simple equations can lead to tremendously erroneous results. These fluctuations in the supplied current are more or less reality in all industrial power electronic rectifiers. In this short communication, we will show mathematically how forgetting to include the power components inflicted by the fluctuating current or using simple equations defined for zero-centered, sinusoidal alternating currents causes incorrect results in the case of water electrolyzers with a fluctuating current supply. Our goal is to remind the scientific community of the importance of using accurate mathematical definitions of active power, along with appropriate measurement setups, to avoid significant errors in determining one of the key performance indicators of water electrolyzers. • Incorrect ways of calculating power in water electrolysis literature are revealed. • An example of the consequences of their use in dynamic operation is given. • Examples of correct experimental methods and data analysis practices are provided. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

38. Thermodynamic consistency of the equation of state of strongly interacting matter

Author

Randrup, Jorgen and Ruuskanen, Vesa P.

Subjects
Equation of State
Abstract

Addressing strongly interacting matter in the region of energy density where the hadronic gas phase coexists with the quark-gluon plasma phase, we discuss how thermodynamic consistency can be used to constrain the equation of state for uniform matter and we illustrate the method by constructing a T_c-dependent family of thermodynamically consistent equations of state based on simple spline interpolations between the gas and plasma phases.

Published
2003

47. Experimental comparison of regeneration methods for CO2 concentration from air using amine-based adsorbent

Author

Elfving, Jere, Kauppinen, Juho, Jegoroff, Mikko, Ruuskanen, Vesa, Järvinen, Lauri, Sainio, Tuomo, Lappeenrannan-Lahden teknillinen yliopisto LUT, Lappeenranta-Lahti University of Technology LUT, and fi=School of Energy Systems|en=School of Energy Systems

Subjects
Regenerability, Adsorbent regeneration, Working capacity, Direct air capture, CO2 adsorption, Specific Energy requirement
Abstract

Comparison of different regeneration options for direct air capture (DAC) has usually been limited to only consider pure CO2 production, limiting the process options to e.g. temperature-vacuum swing adsorption (TVSA) or steam-stripping. In this work, detailed experimental comparison is conducted of temperature swing adsorption (TSA/TCSA) and TVSA for DAC. Particularly, TVSA is assessed with air or inert gas purge flow (TVCSA) and without purge flow. The working capacity, regeneration specific energy requirement (SER) and adsorbent regenerability of these processes was compared. For all other studied regeneration options except TVSA without purge flow, over 85% regeneration was obtained already at 60 °C. Isobaric TSA at 60 °C had the lowest regeneration SER of 4.2 MJ/kgCO2. Coupling TSA with mild vacuum improved desorption rate and increased working capacity from 0.47 to 0.51 mmolCO2/gsorbent, requiring 7.5 MJ/kgCO2 for regeneration. Without purge flow, TVSA resulted in only 0.39 mmolCO2/gsorbent with the SER of 8.6 MJ/kgCO2 at 100 °C. Due to lower allowable regeneration temperature of 60 °C, mild vacuum TVSA with air flow also had a lower cyclic capacity decrease rate of 0.26%/cycle compared to 0.38%/cycle with TVSA without purge flow at 100 °C. However, using 100 °C with air flow in the TVSA process lead to a significant capacity decrease of 0.6%/cycle. Therefore, using either air or inert purge flow below 100 °C coupled with mild vacuum has benefits over the TVSA process with no inflow in terms of CO2 productivity, specific energy requirement and adsorbent regenerability. For utilization purposes that require low-concentration CO2, TVSA with purge flow should thus be considered as a viable regeneration option for direct air capture along with isobaric TSA. Publishers version

Published
2020

Catalog

Books, media, physical & digital resources
See catalog results