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3. Defining worst-performing buildings in Slovenia based on EPCsMarjana Šijanec-Zavrl, Henrik Gjerkeš, 2023, published scientific conference contribution Abstract: The 2021 EC proposal for EPBD recast planned inter alia the harmonization of energy performance certificates (EPCs) across EU and definition of minimum energy performance (MEP) standards to support the renovation of worst-performing buildings. Rescaling of EPCs to a common EU ranking and consequently setting MEP standards is a task for the near future, but current planning of building renovation to meet decarbonization by 2050 may only relay on data in Slovenian EPCs from 2013-2022 data base. The paper presents the analysis of energy related indicators in existing Slovenian EPCs in order to demonstrate that existing EPCs issued in last decade can be used to define 15% of worst-performing buildings prioritized for deep and NZEB renovation, if combined with other indicators, like heat demand.
Keywords: energy performance indicators, decarbonization, energy efficiency, building renovation
Published in RUNG: 27.11.2023; Views: 1940; Downloads: 12
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4. Implementation of the EPBD in Slovenia – Status in 2020Marjana Šijanec Zavrl, Miha Tomšič, Henrik Gjerkeš, Erik Potočar, 2021, final research report Abstract: The Concerted Action EPBD (CA EPBD) addresses the Energy Performance of Buildings Directive (EPBD). It aims to contribute to the reduction of energy use in European buildings, through the exchange of knowledge and best practices in the field of energy efficiency and energy savings between all 28 EU Member States plus Norway.
The CA EPBD is a joint initiative between the EU Member States and the European Commission. It involves representatives of national ministries or their affiliated institutions who are in charge of preparing the technical, legal and administrative framework for the Energy Performance of Buildings Directive in each EU Member State, plus Norway. The objective is to enhance the sharing of information and experiences from national adoption and implementation of this important European legislation.
The transposition of the EPBD in Slovenia is the overall responsibility of the Ministry of Infrastructure and was primarily transposed by the Energy Act (EZ-1), covering the topics of NZEB, energy performance certification, inspection of heating and AC systems and energy efficiency information programmes. The Act on Energy Efficiency (ZURE) integrates the EZ-1 articles related to the EPBD.
The revision of the building codes (PURES) is still in progress and planned for publication in late 2021. It will contain detailed technical requirements for NZEB based on the technical definition given in the national NZEB action plan, and the revision of the calculation methodology according to a new set of CEN EPBD standards.
Important recent steps in EPBD implementation are the application of the central national electronic register of EPCs and associated software, the independent control system for EPCs, first steps in the cross-linking of e-registries for EPCs, inspections and public buildings, as well as wide information activities implemented by the Eco Fund concerning financial instruments available for the energy renovation of buildings.
Keywords: Concerted Action, Energy Performance of Buildings Directive, Act on Energy Efficiency, Slovenia
Published in RUNG: 02.11.2023; Views: 2065; Downloads: 18
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5. Current status and prospects of surface detector of the TAx4 experimentE. Kido, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. A surface detector (SD) array covers approximately 700 km^2, and the SD array is surrounded by three fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with energies greater than 57 EeV from the TA SD data. In order to confirm this evidence with more data, we started the TAx4 experiment which expands the detection area using new SDs and FDs. We started construction of new SDs which are arranged in a square grid with 2.08 km spacing at the north east and south east of the TA SD array. More than half of the new SDs are already deployed and running. We present the current status of the TAx4 SD, trigger efficiency and exposure prospects for the highest energy part of the cosmic ray spectrum.
Keywords: Telescope Array, TAx4, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, trigger efficiency
Published in RUNG: 04.10.2023; Views: 2376; Downloads: 10
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6. 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.
Keywords: ICEC, Power-to-Solid, energy storage, hydrogen, ferrous chloride, electrolysis, Fe deposition, efficiency, XAS, structure and population, ionic species, ion association, conductivity
Published in RUNG: 18.04.2023; Views: 3152; Downloads: 49 (1 vote)
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7. Electrolysis energy efficiency of highly concentrated FeCl[sub]2 solutions for power-to-solid energy storage technologyUroš Luin, Matjaž Valant, 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.
Keywords: electrolysis, ferrous chloride, iron deposition, energy efficiency
Published in RUNG: 16.02.2022; Views: 3567; Downloads: 81 (1 vote)
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8. 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 Keywords: Surgical site infection, BioTrak, Fluorescence, Energy efficiency, Temperature-controlled ventilation, Air sampling
Published in RUNG: 04.01.2021; Views: 5114; Downloads: 0
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9. COST AND ENERGY EFFICIENT MODERNIZATION OF SCHOOL BUILDINGS IN UKRAINEHenrik Gjerkeš, Marjana Šijanec Zavrl, Tetiana Rapina, 2016, other scientific articles 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.
Keywords: cost optimum, energy efficiency, nearly zero energy building, building envelope, heating
Published in RUNG: 15.04.2016; Views: 7316; Downloads: 0
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