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Tilstandsindikatorer for vegnettet – presiseringer for vegnettet i metode for noen indikatorer
No full textNotatet beskriver noen presiseringer i metode for beregning av tilstandsindikator for bæreevne bru, tunnelsikkerhetsforskriften og bæreevne vegpublishedVersio
Effect of Concentration of Lithium Bis(fluorosulfonyl)imide on the Performance of Silicon Anodes for Li-Ion Batteries
Full text linkThe conventional electrolytes for Li-ion batteries are based on the LiPF6 salt and carbonate solvents. Due to challenges with the stability, alternative salts are sought, and lithium bis(fluorosulfonyl)imide (LiFSI) is an interesting candidate. In this work, we investigate the performance of concentrated electrolytes based on LiFSI (range 1–10 M) and carbonate solvents, in combination with low-cost, micron-sized silicon anodes. LiFSI has an excellent solubility, and by use of concentrated electrolytes, corrosion of the aluminium current collector on the cathode side can be avoided, which is otherwise a challenge. The 5 M LiFSI electrolyte (molar salt to solvent ratio of 1:2.5) shows a similar ohmic resistance and rate performance as the 1 M LiFSI electrolyte. The solid electrolyte interphase formed in 5 M LiFSI is thin and dominated by inorganic compounds, in particular LiF. For long-term galvanostatic cycling with a lower cut-off potential of 50 mV, the 1 M LiFSI electrolyte shows the best stability. However, by limiting the lithiation, and thus the expansion of the silicon by increasing the cut-off voltage to 120 mV, the cycling performance is similar for all electrolytes and electrodes deliver > 1000 mAh/g for more than 300 cycles.publishedVersio
Digital Twins for Secure Software Updates to Maintain IoT Device Trustworthiness
Full text linkComprehensive analysis to securing software updates for IoT devices, a critical aspect of maintaining trust and security in IoT ecosystems. It explores the challenges of managing updates in dynamic IoT environments and introduces a novel approach using Digital Twins to enhance the software update lifecycle. The chapter details the integration of Digital Twins with existing security frameworks, emphasizing the benefits of this approach in terms of timeliness, reliability, and scalability. It also presents a proof-of-concept implementation and discusses the practical implications for real-world IoT deployments.publishedVersio
Value-Stacking Battery Services Considering Frequency Markets and Grid-Based Voltage Support
Full text linkBattery Energy Storage System (BESS) can provide frequency support to the power system by adjusting active power flow, but this may negatively impact local voltage. To mitigate this, the BESS can simultaneously inject or absorb reactive power to regulate voltage levels. This work analyzes the reactive power compensation necessary for a BESS to participate in frequency markets while upholding local voltage levels during reserve activation. Using a LinDistFlow framework, a case study on the IEEE 33-bus system is performed for one month of operation for a grid-connected BESS that maximizes profit while upholding the voltage levels in the grid, and reserves reactive power to counteract worst-case voltage impacts. To have sufficient reactive power to counteract voltage impact during activation, the BESS reduces frequency market bids by 34.8%. This consideration impacts the profitability of the BESS, capturing the need to address these service costs with the distribution system operator (DSO).Value-Stacking Battery Services Considering Frequency Markets and Grid-Based Voltage SupportacceptedVersio
Rask evaluering av rehabiliterings-tilbudet ved MS-Senteret Hakadal. Kvalitetsforbedringsprosjekt
Full text linkSINTEF Digital, avd. Helse, faggruppe for helsetjenesteforskning, har på oppdrag fra MS-Senteret Hakadal gjennomført et kvalitetsforbedringsprosjekt med mål om å gi innsikt i gevinsten av rehabiliteringstilbudet for pasientene. Formålet med prosjektet har vært å bidra til tjenesteutvikling og etablere en infrastruktur for fremtidige langsiktige evalueringer. I prosjektet har vi utviklet et nytt evalueringsverktøy, hvor vi i første fase fokuserte på å identifisere hva personer med MS oppfatter som gode rehabiliteringsresultater og hvordan resultater av døgnbasert rehabilitering bør måles. Innsikten ble samlet gjennom kvalitative fokusgruppeintervjuer med inneliggende pasienter og en gjennomgang av relevant forskningslitteratur. Dette resulterte i en kvantitativ spørreskjemapakke som ble distribuert ved innkomst (T1), utskrivelse (T2), og seks uker etter avsluttet opphold (T3) blant pasienter ved fire inntak som deltok på et treukers døgnbasert rehabiliteringsopphold ved senteret. Resultatene fra litteraturgjennomgangen, intervjuer og spørreundersøkelser oppsummeres i denne rapporten.Rask evaluering av rehabiliterings-tilbudet ved MS-Senteret Hakadal. KvalitetsforbedringsprosjektISBN: 978-82-14-07486-4publishedVersio
A new near-wellbore modeling method for deviated wells incorner-point grid
Full text linkThis paper presents the construction of a high-quality, robust hybrid grid for near-wellbore modeling in the vicinity of a deviated well. The far-field region is modeled using a corner-point grid, while the near-wellbore region-referred to as the volume of interest-is remeshed using a layered unstructured grid, which consists of a combination of Voronoi and radial sub-grids. A detailed gridding and simulation workflow is outlined. The construction of the novel layered unstructured grid begins with building a base surface grid on the surface typically aligned to middle well point. The grids on the other surfaces are built through preserving the base topology but adjusting the nodes of base grid to fit the well points deviating from the base well point. A flow-based node rearrangement method is proposed to adjust the grid nodes to gain high-quality grids on each surface. The positions of new nodes are determined by ensuring equal streamlines and pressure values between nodes on the base and target surfaces, improving grid orthogonality as streamlines remain perpendicular to equipotential lines. The method’s ability to generate high-quality grids for deviated wells is demonstrated through illustrative and validation examples. Computational performance is assessed through direct comparisons across three case studies, showing that the new near-wellbore modeling model provides accurate well solutions and pressure maps with a reasonable computational cost. Additionally, the near-wellbore modeling model outperforms standard models in capturing gas flow with high compressibility, describing flow behavior in heterogeneous reservoirs, and predicting production parameters in multilayer systems.publishedVersio
3D-DaVa: Enhancing 3D Point Cloud Data Reliability for Industrial Applications
Full text linkThe escalating incorporation of three-dimensional (3D) point cloud data across industrial applications highlights the necessity of assuring its reliability. The error-prone process of object digitization, the large data volumes, and equipment inaccuracies can lead to the degradation of 3D point cloud data quality by introducing varying degrees of noise, outliers, and missing values. Therefore, there is a pressing need for a generally applicable, comprehensive, and robust solution to effectively validate the integrity of point cloud data and assess its quality. Such a solution would empower professionals to rely on this data for critical decision-making, covering applications within many domains, such as manufacturing, automotive, and robotics. In this article, we propose, apply, and assess the 3D Point Cloud Data Validation (3D-DaVa) pipeline, an automated 3D data validation system incorporating statistical and machine learning techniques. The pipeline takes a point cloud and its reference as input and outputs accuracy, validity, and completeness scores. We demonstrated the efficacy of 3D-DaVa through a rigorous evaluation using both real-world manufacturing data and openly available data, where we deliberately introduced distortions covering five distortion levels by simulating common inaccuracies. The data quality assessment results obtained by varying distortion levels reveal a decreasing trend with a distortion increase, thus underscoring the 3D-DaVa’s capability to quantify such deviations accurately.publishedVersio
COFACTOR Drammen dataset - 4 years of hourly energy use data from 45 public buildings in Drammen, Norway
Full text linkTo limit energy consumption and peak loads with increased electrification of our society, more information is needed about the energy use in buildings. This article presents a data set that contains 4 years (Jan. 2018- Dec. 2021/Mar. 2022) of hourly measurements of energy and weather data from 45 public buildings located in Drammen, Norway. The buildings are schools (16), kindergartens (20), nursing homes (7) and offices (2). For each building, the data set contains contextual data about the buildings including their floor area, construction year, energy label, information about their heating system and ventilation system in addition to time series data of energy use and weather data. For some of the buildings, the energy measurements only contain measurements of hourly imported electricity, while the time series data for other buildings have submeters for different energy services and technologies. Researchers, energy analysts, building owners and policy makers can benefit from the dataset for e.g. hourly load disaggregation, forecasting of energy loads and flexibility, grid planning and modelling activities.publishedVersio
On the potential role of flexible Norwegian hydropower in managing challenging renewable energy variability events in Europe
Full text linkPrevious research has identified flexible Norwegian hydropower as one potential key resource for managing variations in wind and solar power in Northern Europe. There is, however, a need for further detailed examination of this potential role of Norwegian hydropower based on updated future scenarios and using the latest data and model tools available. We analyze potential power system impacts of expanding Norwegian hydropower flexibility and Norway-Europe transmission, considering renewable energy variability based on a simulation for the historical weather years 1991-2020. The simulations are performed using FanSi, a stochastic optimization model for analyzing large-scale power systems with significant shares of hydropower combined with high shares of wind/solar power. A year 2050 scenario for Europe from the integrated energy system model SCOPE SD is used as framework for our analysis with FanSi. Our results highlight how expanded hydropower and transmission can potentially reduce price spikes during periods of low wind/solar output, reduce wind/solar energy curtailment during periods of high wind/solar output; and reduce price differences between interconnected areas during periods of either low or high wind/solar output. We demonstrate that these effects are attributable to more dynamic operation and expanded operational ranges of hydropower and transmission in the simulations assuming expanded hydropower and transmission capacities. We acknowledge high fundamental uncertainty in modelling a future system for the year 2050.On the potential role of flexible Norwegian hydropower in managing challenging renewable energy variability events in EuropepublishedVersio
Integration of electrical energy storage in wave energy hardware-in-the-loop test rigs
Full text linkThis paper presents a design methodology for integrating an electrical energy storage unit into a hardware-in-the-loop (HIL) test rig for wave energy converters (WECs). Typically, the power production from WECs is characterised by pronounced fluctuations at low frequency and high peaks compared to the average. Wave energy test rigs should be able to reproduce these variations to impose realistic conditions to the device under test. Thus, the grid connection of the rig must be sized to cope with high peaks, and additional measures may be required to avoid disturbances on nearby loads and negative effects on voltage quality. The integration of electrical energy storage can smoothen power fluctuations and mitigate these drawbacks, while resulting in lower installation and operating costs. The design methodology indicates how to effectively size the storage unit and which technology to favour based on the type and duration of test campaigns. Numerical simulation results are presented for a dual HIL test rig and operational profiles of three different WEC technologies. For designs with energy storage lifetime shorter than the calendar life, sensitivity analyses indicate that the rig's annual utilisation rate and the level of accelerated testing have a significant effect on the storage energy requirements.Integration of electrical energy storage in wave energy hardware-in-the-loop test rigsacceptedVersio