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  • 1.
    Arrhenius, Karine
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Bohlen, Haleh
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Büker, Oliver
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    de Krom, Iris
    VSL Dutch Metrology Institute, Netherlands.
    Heikens, Dita
    VSL Dutch Metrology Institute, Netherlands.
    van Wijk, Janneke
    VSL Dutch Metrology Institute, Netherlands.
    Hydrogen purity analysis: Suitability of sorbent tubes for trapping hydrocarbons, halogenated hydrocarbons and sulphur compounds2020In: Applied Sciences, E-ISSN 2076-3417, Vol. 10, no 1, article id 120Article in journal (Refereed)
    Abstract [en]

    The ISO 14687-2 standard sets requirements for the purity of the hydrogen that is delivered at refuelling stations. These specifications cover a wide range of impurities and include challenging measurements, mainly due to the very low levels of the required detection limits and the need for "total" measurements (total hydrocarbons, total sulphur compounds, halogenated compounds). Most of the compounds belonging to the species are organic. Thermal desorption often coupled with gas chromatography is a common speciation method used to determine the content of organic impurities. However, no existing sorbent tubes are sufficiently universal to trap all possible impurities; depending on the sorbents and the sampling volume, some compounds may irreversibly adsorb or may break through. It is therefore necessary to evaluate sorbents for the compounds targeted at the level required. In this study, the suitability of sorbent tubes for trapping organic impurities in hydrogen was investigated. Suitable sorbents were selected based on a literature review of suitable sorbent materials. Short-term stability studies for compounds among hydrocarbons, halogenated compounds and sulphurcompounds on the selected sorbents have then been performed for storage periods of two weeks since this is the period typically required to complete the collection, transport and analysis of hydrogen samples. The study clearly shows that the method is promising for total species, even through the results show that not all of the compounds belonging to the three total species to be analysed when performing hydrogen purity analysis can be quantified on one unique sorbent. A multibed sorbent consisting of Tenax TA (weak), Carboxen 1003 (medium), Carbograph 1 (strong) is shown to be a versatile sorbent suitable for the three "total species"; only a few compounds from each family would need to be analysed using other analytical methods. This method proposed here for total species will not only provide a sum of concentrations, but also an identification of which compound(s) is/are actually present in the hydrogen.

  • 2.
    Arrhenius, Karine
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Fischer, Andreas
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Büker, Oliver
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Adrien, Herve
    INERIS Parc Alata, France.
    El Masri, Ahmad
    INERIS Parc Alata, France.
    Lestremau, Francois
    INERIS Parc Alata, France.
    Robinson, Tim
    Waverton Analytics Ltd, UK.
    Analytical methods for the determination of oil carryover from CNG/biomethane refueling stations recovered in a solvent2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 10, no 20, p. 11907-11917Article in journal (Refereed)
    Abstract [en]

    Vehicle gas is often compressed to about 200 bar at the refueling station prior to charging to the vehicle's tank. If a high amount of oil is carried over to the gas, it may cause damage to the vehicles; it is therefore necessary to accurately measure oil carryover. In this paper, three analytical methods for accurate quantification of the oil content are presented whereby two methods are based on gas chromatography and one on FTIR. To better evaluate the level of complexity of the matrix, 10 different compressor oils in use at different refueling stations were initially collected and analysed with GC and FTIR to identify their analytical traces. The GC traces could be divided into three different profiles: oils exhibiting some well resolved peaks, oils exhibiting globally unresolved peaks with some dominant peaks on top of the hump and oils exhibiting globally unresolved peaks. After selection of three oils; one oil from each type, the three methods were evaluated with regards to the detection and quantification limits, the working range, precision, trueness and robustness. The evaluation of the three measurement methods demonstrated that any of these three methods presented were suitable for the quantification of compressor oil for samples. The FTIR method and the GC/MS method both resulted in measurement uncertainties close to 20% rel. while the GC/FID method resulted in a higher measurement uncertainty (U = 30% rel.).

  • 3.
    Badrzadeh, B
    et al.
    Australian Energy Market Operator, Australia.
    Emin, Zia
    PSC Power Systems Consultants, USA.
    Hillberg, Emil
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Jacobson, D
    Manitoba Hydro, Canada.
    Kocewiak, L
    Ørsted Offshore, Denmark.
    Lietz, G
    Digsilent, Germany.
    da Silva, F
    Aalborg university, Denmark.
    Val Escudero, M
    Eirgrid, Ireland.
    The Need or Enhanced Power System Modelling Techniques and Simulation Tools2020In: CIGRE SCIENCE & ENGINEERING, E-ISSN 2426-1335, Vol. 17, no Febr, p. 30-46Article in journal (Refereed)
    Abstract [en]

    The transition to a clean energy future requires thorough understanding of increasingly complex interactions between conventional generation, network equipment, variable renewable generation technologies (centralised and distributed), and demand response. Secure and reliable operation under such complex interactions requires the use of more advanced power system modelling and simulation tools and techniques. Conventional tools and techniques are reaching their limits to support such paradigm shifts. This paper provides an overview of commonly used and emerging power system simulation tools and techniques. Applications of these tools ranging from real-time power system operation to long-term planning are also discussed. Various approaches to gain confidence in the accuracy and applicability of the simulation models are presented. The paper then discusses emerging trends in simulation tools and techniques primarily stemming from the transition to a power system with increased penetration of inverter-based resources as these are used in variable renewable energy technologies.

  • 4.
    Brolin, Magnus
    et al.
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Pihl, Hjalmar
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Design of a local energy market with multiple energy carriers2020In: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 118, article id 105739Article in journal (Refereed)
    Abstract [en]

    Recent developments in the electric power sector as well as in district heating and cooling systems has led to an increased interest in local energy systems and markets. In the electricity sector, this is driven by the integration of distributed resources such as solar power, electric vehicles and demand response. For district heating, sustainability and energy efficiency targets drives the development to further exploit small-scale heat sources. A closer integration of these energy carriers can also unlock potential flexibility, to the benefit of local as well as overlaying systems. In this respect, there is a need to further explore the possibilities to design local energy markets to facilitate the integration between electricity and district heating, as well as providing adequate instruments enabling flexibility. This paper therefore presents a market clearing design, based on optimization, for local energy markets incorporating multiple energy carriers and bid structures suitable for representing flexibility. The market clearing model is applied in a case study to illustrate and validate key design elements. One conclusion is that even though various elements can be added to the market clearing function, there is a challenge to interpret the results due to an increased complexity of the resulting optimization problem. 

  • 5.
    Rieck, Carsten
    et al.
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Jaldehag, kenneth
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Ebenhag, Sven-Christian
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Jarlemark, Per
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Hedekvist, Per Olof
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Time and frequency laboratory activities at RISE2020In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI, Institute of Electrical and Electronics Engineers Inc. , 2020, p. 169-180Conference paper (Refereed)
    Abstract [en]

    RISE Research Institutes of Sweden is since 2018 the result of a rebranding of SP Technical Research Institute of Sweden and several other national research facilities and test beds in Sweden. This also comprises most national metrology institute (NMI) activities, including time and frequency that is still located at its Borås facilities in the southwest of Sweden since 1995. UTC(SP) remains the official designation of the Swedish UTC(k) realization. It is realized in a classical master clock and phase stepper setup and is locally distributed to different users and time transfer applications. The most recent local clock ensemble consists of four hydrogen masers and three high performance 5071A Cs standards. UTC(SP) is linked to TAI using TWSTFT and GNSS. The primary link is a combination TWGPPP with current calibration uncertainties of 1.1 ns. The time scale is regularly kept within ±5 ns of UTC. RISE has also established several distributed UTC(SP) copies, with both local backups in Borås and facilities at remote sites linked together by GNSS time transfer. Network time distribution at those sites make UTC(SP) publicly available. Additionally, RISE offers several calibration services for the distribution of UTC-traceable time and frequency signals. Time and frequency related metrological research at RISE is mostly concentrated on further refinement of GNSS and TWSTFT methods, their calibration and the dissemination using those methods. We are also active in research on fiber based optical time and frequency transfer. Outside the metrological responsibilities, many research projects focus on establishing metrological aspects of time and frequency within for instance the automotive and maritime domain.

  • 6.
    Silander, Isak
    et al.
    Umeå University, Sweden.
    Forssen, Clayton
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology. Umeå University, Sweden.
    Zakrisson, Johan
    Umeå University, Sweden.
    Zelan, Martin
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Axner, Ove
    Umeå University, Sweden.
    Invar-based refractometer for pressure assessments2020In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 45, no 9, p. 2652-2655Article in journal (Refereed)
    Abstract [en]

    Gas modulation refractometry (GAMOR) is a methodology that can mitigate fluctuations and drifts in refractometry. This can open up for the use of non-conventional cavity spacer materials. In this paper, we report a dual-cavity system based on Invar that shows better precision for assessment of pressure than a similar system based on Zerodur. This refractometer shows for empty cavity measurements, up to 104 s, a white noise response (for N2) of 3 mPa s1=2. At 4303 Pa, the system has a minimum Allan deviation of 0.34 mPa (0.08 ppm) and a long-term stability (24 h) of 0.7 mPa. This shows that the GAMOR methodology allows for the use of alternative cavity materials.

  • 7.
    von Platten, Jenny
    et al.
    RISE Research Institutes of Sweden, Built Environment, System setup and Service Innovation. Lund University, Sweden.
    Sandels, Claes
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Jörgensson, Kajsa
    Lund University, Sweden.
    Karlsson, Viktor
    Lund University, Sweden.
    Mangold, Mikael
    RISE Research Institutes of Sweden, Built Environment, System setup and Service Innovation.
    Mjörnell, Kristina
    RISE Research Institutes of Sweden, Safety and Transport. Lund University, Sweden.
    Using Machine Learning to Enrich Building Databases—Methods for Tailored Energy Retrofits2020In: energies, E-ISSN 1996-1073, Vol. 13, no 10Article in journal (Refereed)
    Abstract [en]

    Building databases are important assets when estimating and planning for national energy savings from energy retrofitting. However, databases often lack information on building characteristics needed to determine the feasibility of specific energy conservation measures. In this paper, machine learning methods are used to enrich the Swedish database of Energy Performance Certificates with building characteristics relevant for a chosen set of energy retrofitting packages. The study is limited to the Swedish multifamily building stock constructed between 1945 and 1975, as these buildings are facing refurbishment needs that advantageously can be combined with energy retrofitting. In total, 514 ocular observations were conducted in Google Street View of two building characteristics that were needed to determine the feasibility of the chosen energy retrofitting packages: (i) building type and (ii) suitability for additional façade insulation. Results showed that these building characteristics could be predicted with an accuracy of 88.9% and 72.5% respectively. It could be concluded that machine learning methods show promising potential to enrich building databases with building characteristics relevant for energy retrofitting, which in turn can improve estimations of national energy savings potential.

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