1. COST AND ENERGY EFFICIENT MODERNIZATION OF SCHOOL BUILDINGS IN UKRAINETetiana Rapina, Marjana Šijanec Zavrl, Henrik Gjerkeš, 2016, short scientific article Abstract: Improvement of the energy efficiency of existing buildings in EU has great potential in the efforts to reduce energy consumption, which is with no doubt relevant issue also for Ukraine. In this article the importance of public building stock modernization was analysed with special focus on school buildings. The optimal cost methodology was used to evaluate not only the economic, but also environmental as well as social effects of school building stock modernization. In searching for the optimal level of energy-efficient modernization of school buildings in Ukraine, the European and Slovenian experiences were used. It is demonstrated that the sustainable reconstruction with the nearly-Zero Energy Building (nZEB) guidelines, as defined in EU regulations, is feasible with good results and can be recommended also for reconstruction of school buildings in Ukraine.
Found in: ključnih besedah
Summary of found: ...Improvement of the energy efficiency of existing buildings in EU has great...
Keywords: cost optimum, energy efficiency, nearly zero energy building, building envelope, heating
Published: 15.04.2016; Views: 4604; Downloads: 0
 Fulltext (474,44 KB) |
2. Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflowMalin Alsved, A. Civilis, P. Ekolind, Tina Šantl Temkiv, Jakob Löndahl, 2017, original scientific article Found in: ključnih besedah
Summary of found: ...Surgical site infection,
BioTrak,
Fluorescence,
Energy efficiency,
Temperature-controlled ventilation,
Air sampling...
Keywords: Surgical site infection, BioTrak, Fluorescence, Energy efficiency, Temperature-controlled ventilation, Air sampling
Published: 04.01.2021; Views: 1636; Downloads: 0
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3. Electrolysis energy efficiency of highly concentrated FeCl[sub]2 solutions for power-to-solid energy storage technologyMatjaž Valant, Uroš Luin, 2022, original scientific article Abstract: An electrochemical cycle for the grid energy storage in the redox potential of Fe involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial to maximize the energy efficiency of the electrolysis process. Here we present a study of the influence of electrolysis parameters on the energy efficiency of such electrolysis, performed in an industrial-type electrolyzer. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency. The deviation from the correlation indicated an important contribution from the conductivity of the ion-exchange membrane. Another important studied parameter was the applied current density. We quantitatively showed how the contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ± 3% was achieved using 2.5 mol L−1 FeCl2 solution at 70 °C and a current density of 0.1 kA m−2. In terms of the energy input per Fe mass, this means 1.88 Wh g−1. The limiting energy input per mass of the Fe deposit was found to be 1.76 Wh g−1.
Found in: ključnih besedah
Keywords: electrolysis, ferrous chloride, iron deposition, energy efficiency
Published: 16.02.2022; Views: 945; Downloads: 67
(1 vote)
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4. Efficiency of the grid energy storage technology based on iron-chloride material cycleUroš Luin, doctoral dissertation Abstract: Future high-capacity energy storage technologies are crucial for a highly renewable energy mix, and their mass deployment must rely on cheap and abundant materials, such as iron chloride. The iron chloride electrochemical cycle (ICEC), suitable for long-term grid energy storage using a redox potential change of Fe2+/Fe, involves the electrolysis of a highly concentrated aqueous FeCl2 solution yielding solid iron deposits. For the high overall energy efficiency of the cycle, it is crucial maximizing the energy efficiency of the electrolysis process. The thesis presents a study of the influence of electrolysis parameters on energy efficiency, performed in an industrial-type electrolyzer system. We studied the conductivity of the FeCl2 solution as a function of concentration and temperature and correlated it with the electrolysis energy efficiency as a function of current density. The contribution of the resistance polarization increases with the current density, causing a decrease in overall energy efficiency. The highest energy efficiency of 89 ±3 % was achieved using
2.5 mol dm-3 FeCl2 solution at 70 °C and a current density of 0.1 kA m-2.
In terms of the energy input per Fe mass, this means 1.88 Wh g-1. The limiting energy input per mass of the Fe-deposit, calculated by extrapolating experimental results toward Eocell potential, was found to be 1.76 Wh g-1. For optimal long-duration electrolysis efficiency and performance, the optimal catholyte concentration range is
1-2 mol dm-3 FeCl2. We performed in situ X-ray absorption spectroscopy experimental studies to validate theoretical conclusions from literature related to the population and structure of Fe-species in the FeCl2 (aq) solution at different concentrations (1 - 4 mol dm-3) and temperatures (25 - 80 °C). This revealed that at low temperature and low FeCl2 concentration, the octahedral first coordination sphere around Fe is occupied by one Cl ion at a distance of 2.33 (±0.02) Å and five H2O at a distance of 2.095 (±0.005) Å. The structure of the ionic complex gradually changes with an increase in temperature and/or concentration. The apical H2O is substituted by a Cl ion to yield a neutral Fe[Cl2(H2O)4]0. The transition from the charged Fe[Cl(H2O)5]+ to the neutral Fe[Cl2(H2O)4]0 causes a significant drop in the solution conductivity, which well correlates with the existing state-of-the-art conductivity models. An additional steric impediment of the electrolytic cell is caused by the predominant neutral species present in the catholyte solution at high concentration. This correlates with poor electrolysis performance at a very high catholyte concentration (4 mol dm-3 FeCl2), especially at high current densities (> 1 kA m-2). The neutral Fe[Cl2(H2O)4]0 complex negatively affects the anion exchange membrane ion (Cl-) transfer and lowers the concentration of electroactive species (Fe[Cl(H2O)5]+) at the cathode surface. The kinetics of hydrogen evolution from the reaction between Fe powder and HCl acid was studied under the first-order reaction condition. The activation energy was determined to be 55.3 kJ mol-1.
Found in: ključnih besedah
Keywords: ICEC, Power-to-Solid, energy storage, hydrogen, ferrous chloride, electrolysis, Fe deposition, efficiency, XAS, structure and population, ionic species, ion association, conductivity
Published: 18.04.2023; Views: 189; Downloads: 12
(1 vote)
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