IMEKO TC20: International Conference on Measurements of Energy

Dr. Fabian Plag is a metrologist for renewable energy, working at PTB since 2014. He is an expert in the field of photovoltaic with more than 10 years of experience in this area. He studied physics and renewable energy and energy efficiency, was employed in industry – working in the R&D department of a supplier for photovoltaic metrology systems. During his work at PTB he participated in several international metrology research projects. The results of his PhD thesis contributed input into the standardisation work of IECs Technical Committee 82: Solar photovoltaic energy systems.

Since 2019 Fabian coordinates the Innovation Cluster Energy at PTB - acting as central point of contact for internals and externals. Since then, he has also been increasingly involved with PTB's hydrogen strategy and in the development of strategic roadmaps covering metrology for energy, environment, and climate. Since 2021 Fabian coordinates the EMPIR Project Support for a European Metrology Network for Clean Energy.

The energy transition from a predominantly fossil-fueled to a carbon neutral, sustainable and emission free energy system is one of the key challenges of our society. In this context, the metrology community plays a vital role by providing robust metrological solutions that underpin technological advancements and facilitate their successful implementation in the market. After all, reliable measurements are the prerequisite for a safe, secure, reliable, and accessible energy supply. The Physikalisch-Technische Bundesanstalt (PTB), the metrology institute of Germany, has set up the Innovation Cluster Energy (IC-E) combining its scientific disciplines to address the metrological aspects of energy transition and to pool PTB’s activities in the field of renewable energies.

The work of IC-E includes measurement and calibration capabilities in the fields of solar energy and wind power which - in part - are unique worldwide, metrology for energy transition and distribution, energy storage elements, and metrological solution for the rapidly increasing development of hydrogen technologies as well as the cross-cutting topic on energy efficiency. Together with partners from industry, PTB’s scientists are also developing suitable measuring methods and standards in these fields of work. Beside single disciplines the focus is on the coupling of energy sectors, on the reliable and secure operation of the electricity grid, and on hydrogen and its derivatives as energy carrier.

This contribution aims to provide an overview of the Innovation Cluster Energy, its interaction to digital and environmental topics and its links to European metrology networks EMNs under EURAMET, the European association of national metrology institutes.

Dr. Stefan Winter has been working in the field of PV metrology at PTB since the early 1990s. He was the respective first working group leader of the “Solar Cells” and “Solar Modules” working groups. Since 2017, he is head of the department 4.5 "Applied Radiometry". Stefan Winter contributes to national and international standardization in PV, where he is a member of the German Committee DKE 373 and the IEC TC82-WG2. In this function, he was project leader of several standardization projects on metrological PV topics. To improve PV metrology at European level, he coordinated the projects PhotoClass, PV-Enerate and Metro-PV. At national level, he is head of the Competence Centre for PV Metrology. In addition, Stefan Winter is supporting the Digital Calibration Certificate, is involved in the development of new general methods for calculating measurement uncertainties and initiated wiki.pvmet.org about PV-Metrology.

Photovoltaic energy is a main pillar of the energy transition. Hundreds of billions of Euro will be invested every year world-wide. Consequently, every percent of measurement uncertainty leads to a financial uncertainty of billions of euros. For this reason, a measurement infrastructure for the photovoltaic sector has been established at PTB, which makes it possible to determine the power of cells and modules with the world's smallest measurement uncertainty.

For the yield of solar modules, however, not only the performance under standard test conditions is important, but also the efficient behavior of the solar module under all irradiation and weather conditions that occur during the course of a year in the climate zone concerned. Therefore, the "Energy Rating" according to IEC 61853 also considers the solar module behavior at different temperatures, irradiances, sun angles and even the influence of the wind. For the quantitative determination of the corresponding solar module properties, measuring facilities have been set up, which are presented in an overview.

Dr. Olav Werhahn earned his professional credentials as Physicist from Leibniz University Hannover and the Max-Planck-Institut für Strömungsforschung, Göttingen. Olav Werhahn provided his understanding of laser spectroscopy to PTB since 2000. At PTB, he has dedicated his career to ultrashort pulse laser safety, and from 2002 to laser spectroscopy-based gas metrology, making significant contributions through his research, innovation, and practical insights to advanced spectroscopic methods providing metrological traceable amount fractions. Throughout his professional journey, Olav Werhahn has garnered recognition for his work on the method of Traceable Infrared Laser-Spectrometric Amount fraction Measurement (TILSAM), which he developed together with the Danish national metrology institute. With a genuine passion for metrology and spectroscopy, Olav Werhahn has become head of working group “Spectrometric Gas Metrology” at PTB. His ability to oversee processes and relations promoted Olav Werhahn becoming Executive Secretary of the Joint Committee of the Regional Metrology Organizations and the BIPM (JCRB) in 2021. For this, Olav Werhahn spent some two years with the International Bureau for Weights and Measures (BIPM), located close to Paris. At the BIPM, and together with the BIPM Director as the Chairperson, Olav Werhahn served the JCRB and the harmonization of the global metrology community, dealing with policy revisions and support of the CIPM Mutual Recognition Arrangement (CIPM MRA). Digital transformations of CIPM MRA activities that are related to the findings of an international survey carried out by Olav Werhahn led to new options articulating metrological traceability statements in the digital world, simplified concepts, e.g., for digital calibration certificates. Moreover, Olav Werhahn has some track record of collaborating with leading metrology institutes, and research organizations. Since August 2023, Olav Werhahn returned to PTB working in his new role as coordinator of the Innovation Cluster for Climate and Environment Metrology at PTB.

Metrology has been successful with a couple of well proven concepts. One of those is comparing results and data with other groups, originating from other instrumentation, or methodologies. The most renown framework to organize, perform and report comparisons for metrology is the CIPM Mutual Recognition Arrangement (CIPM MRA). Since almost a quarter of a century, this metrology framework provides one of the most fundamental backbones of international measurement community around the globe. Key actors in the framework of the CIPM MRA next to the participating laboratories (National Metrology Institutes, NMIs and Designated Institutes, DIs) are the regional metrology organizations (RMOs) and the BIPM (in its greater meaning, i.e., the global organization). Harmonization and overseeing of all activities are managed by the Joint Committee of the RMOs and the BIPM (JCRB). This presentation is to highlight the latest developments of the JCRB and the outcomes of the CIPM MRA. A perfect use case for this is seen in the emerging hydrogen metrology serving needs and challenges of the hydrogen economy to diversify the energy market. The BIPM’s Key Comparison Database (KCDB) for this serves as a valuable foundation of data and metrological solutions for measurement tasks on hydrogen.

As the outcome of the CIPM MRA, calibration and measurement capabilities get published by NMIs and DIs in the KCDB, the so-called CMCs. Alongside, the KCDB provides data and reports on all key (KC) and supplementary (SC) comparisons undertaken in the various metrology areas. Focusing on the hydrogen topic, different metrology areas are challenged for different quantities to be measured, all serving measurement tasks related to hydrogen, e.g., temperature, pressure, volume, mass flow, amount fractions, and isotope ratios. The contribution will showcase that different solutions and capabilities to measurement tasks are provided by the KCDB-listed CMCs and KCs/SCs, even though, at the time of publishing, the hydrogen was not yet in focus of the measurement community. It is the JCRB and the CIPM MRA key actors, including the RMOs, AFRIMETS, APMP, COOMET, EURAMET, GULFMET, and SIM, who cares for fair-play, scientific rigour and transparency worldwide making these metrology data internationally accepted.

The contribution attempts combining the two aspects, international metrology and hydrogen as source for future energy diversification. This way, metrology solutions to hydrogen measurement tasks will be discussed and hydrogen measurement needs requested to the metrology community taken up.

Dr. Richard Högström earned his educational credentials from Aalto University where he holds a Doctoral degree in Measurement Science and Technology. He has earned his professional credentials from VTT MIKES, National Metrology Institute of Finland. Richard Högström possesses a deep understanding of Mechanical and Thermal metrology with more than 15 years of working experience. He has dedicated his career to advancing metrology in diverse fields, including dynamic pressure, humidity, gas flow, mass and aerosol particle metrology, making significant contributions through his research, innovation, and practical insights. Throughout his professional journey, Richard Högström has garnered widespread recognition for his exceptional achievements in developing new calibration and measurement methods, including primary methods in new areas of metrology, such as dynamic pressure and aerosol particles. He has been awarded distinctions for his groundbreaking work, underscoring his expertise and influence in the field. He has delivered keynote speeches and conducted workshops at renowned conferences and events worldwide. Moreover, Richard Högström has an impressive track record of collaborating with leading industry players, academic institutions, and research organizations. His collaborative mindset and interdisciplinary approach have fostered groundbreaking partnerships that have driven advancements in the field of Mechanical and Thermal metrology.

Dynamic pressure measurements are a key requirement for process control in many demanding applications, such as internal combustion engines and gas turbines in power plants, aircrafts, ships and cars, as well as manufacturing, ammunition and explosion safety testing. However, the current practice of calibrating pressure sensors under static conditions significantly limits the achievable measurement accuracy — errors of up to 10 % can occur when sensors are used at dynamically changing conditions. Improvements in accuracy and reliability of dynamic measurements will enable development of next generation technologies and products with improved quality, energy and material efficiency, and safety. For instance, better knowledge about the pressure inside a combustion engine is needed for improving engine performance, i.e. engine power and fuel consumption. Within the European metrology research project DynPT (Development of measurement and calibration techniques for dynamic pressures and temperatures; 2018 - 2021) improved measurement and calibration techniques for dynamic pressures up to 400 MPa were developed. The main objective of the project was to: (a) Develop new measurement standards and validated calibration procedures; (b) Study the effect of different influencing factors on the dynamic sensor response with the aim of defining the most appropriate calibration procedures and measurement uncertainties in industrial applications; (c) Develop and validate new sensors for measuring dynamic pressure in demanding industrial applications, such as inside an internal combustion engine. Measurement standards for dynamic pressures (shock tubes and drop-weight devices) were developed to provide SI traceable calibrations in a wide pressure and frequency range 0.1 – 400 MPa and 1 – 30 kHz, respectively. The target uncertainty of 1 % for dynamic pressure was achieved in the pressure and frequency range up to 5 MPa and 100 Hz. At higher pressures and frequencies, the uncertainties were in the order of 2 % and 5 %, respectively. Studies on the influence of process conditions show that the response of dynamic pressure sensors is strongly frequency dependent even at frequencies well below the nominal resonance frequency of the sensor. Also, temperature was found to influence the response. Moreover, a novel sensor for dynamic pressure measurements at harsh conditions was developed and validated in real engine environments. As an outcome of the project, a solid metrological basis for dynamic pressure measurements was established for the first time. Calibration services, guidelines and new measurement technologies have been made available to industry to facilitate a shift from static to dynamic methods.

Dr. Nils Hansen earned his PhD in Physical Chemistry from the Christian-Albrechts-Universität Kiel, Germany, Nils possesses a deep understanding of kinetics in complex reaction networks as found in combustion, catalysis, and plasmas. He has dedicated his career to mass spectrometric detection and quantification of key intermediates in reaction networks using advanced mass spectrometric tools, making significant contributions through his research, innovation, and practical insights. Throughout his professional journey, Nils Hansen has garnered widespread recognition for his exceptional achievements. He has been recognized as a Fellow of the Combustion Institute and a Helmholtz International Fellow for his groundbreaking work, underscoring his expertise and influence in the field. With a genuine passion for knowledge dissemination, Nils Hansen has become a beacon of inspiration for aspiring professionals. He has delivered captivating keynote speeches, participated in panel discussions, and conducted workshops at renowned conferences and events worldwide. His ability to simplify complex concepts and engage diverse audiences has earned him high praise and a loyal following. Moreover, Nils Hansen has an impressive track record of collaborating with leading academic institutions, and research organizations. His collaborative mindset and interdisciplinary approach have fostered groundbreaking partnerships that have driven advancements in chemical transformation.

Basic chemical insights are needed to support the transition to energy-efficient chemical transformations such as heterogenous catalytic oxidation and plasma-assisted processes. This presentation highlights the basic concepts of our mass spectrometry approaches to study the reaction networks in these complex environments and applications.  Using this technique, unprecedentedly detailed chemical insights are generated as it allows for the simultaneous and sensitive detection of all intermediates and products of the reaction network without prior knowledge of their identity. In the first part of the talk, we will highlight the chemical insights into plasma-assisted chemical looping combustion of simple hydrocarbons by CuO/NiO using low-temperature plasmas in a heated fixed bed, coaxial, double dielectric barrier discharge (DBD) reactor. Through time-dependent species measurements by an electron-ionization molecular beam mass spectrometer, we obtained chemical insights through the quantitative detection of intermediate and product species at various temperature and plasma conditions. We observed considerable enhancement of fuel oxidation from the plasma discharge at lower temperatures. At more elevated temperatures. A period of carbon build-up was observed when using NiO as an oxygen carrier. The second part of the talk highlights new insights into catalytic oxidation conversion of methanol near atmospheric pressure using near-surface molecular-beam mass spectrometry. In addition to a variety of stable C1-C3 species, we detected methoxymethanol (CH3OCH2OH), a reactive C2 oxygenate that had been proposed to be a critical intermediate in methyl formate production. Methoxymethanol was observed above Pd, Au^xPd^y alloys, and oxide-supported Pd. We explored temperature and reactant feed ratio dependencies of methoxymethanol generation. The results suggest that future development of catalysts and microkinetic models for methanol oxidation should be augmented and constrained to accommodate the formation, desorption, adsorption, and surface reactions involving methoxymethanol.

Mr. Zihang Song is working as a research associate at Physikalisch-Technische Bundesanstalt, where he is pursuing his Ph.D. on the traceable efficiency determination of electrical drivetrains. Zihang Song completed his Bachelor of Engineering at Tongji University in Automotive Engineering and earned his Master of Science from the Technical University Braunschweig in Electromobility. He has dedicated his time as a Ph.D. student to the EMPIR project titled "Traceable Mechanical and Electrical Power Measurement for Efficiency Determination of Wind Turbines," and he has made significant contributions through his research, innovation, and practical insights.

Wind energy is projected to be the primary contributor to the expansion of renewable energies, and improving efficiency is one of the major objectives in the development process of wind turbine drivetrains. A method for determining the efficiency of wind turbine drivetrains on nacelle system test benches (NTBs) in a traceable and comparable manner has been sought after. The EMPIR project 19ENG08 WindEFCY [1]  successfully tackled this challenge by devising an efficiency determination method based on traceable mechanical and electrical power measurements.

In the preceding study [2], we established the efficiency of a 2.75 MW full size converter based wind turbine with full traceability at various operating points on the 4 MW NTB situated at the Center for Wind Power Drives (CWD) of RWTH Aachen University. To achieve this, specialized transfer standards for mechanical and electrical power measurement were installed as integral components of the NTB. The measured overall system efficiency demonstrated 89 % at rated torque and speed. For the entirety of the operating range, the relative expanded measurement uncertainty for the efficiency was calculated to be between 0.30 % and 0.72 %.

In this paper, the same wind turbine nacelle is switched from a full size converter (FSC) to Doubly Fed Induction Generator (DFIG) converter. In the new converter concept, the generator’s stator windings are directly connected to the grid, while the rotor windings are controlled through the power converter. Since the rotor currents are only a third of the stator current, the power electronics can be downscaled, resulting in lower costs of the system.

To investigate the system efficiency using DFIG converter, the wind turbine is measured at various operating points, allowing efficiency to be determined and visualised over a wide operating range. Using in-situ calibrated torque sensor on the low speed shaft (LSS) and external calibrated torque sensor on the high speed shaft (HSS), as well as current and voltage transducers, measurement uncertainty for efficiency determination is calculated for each measurement points. The measurement results are showing a metrologically approved system efficiency of 93 % at rated torque and speed using the DFIG converter system, which indicates a significant efficiency improvement of over 4 % comparing to the previously measured full converter system.

[1]       P. Weidinger et al., “Need for a traceable efficiency determination method of nacelles performed on test benches,” Meas. Sensors, vol. 18, p. 100159, 2021, doi: 10.1016/j.measen.2021.100159.

[2]       Z. Song et al., “Traceable efficiency determination of a 2.75 MW nacelle on a test bench,” Forsch. im Ingenieurwes., vol. 87, no. March 2023, pp. 259–273, doi: 10.1007/s10010-023-00650-1.

Fei Qi is a Chair professor at Shanghai Jiao Tong University (SJTU). He received his Ph.D. from University of Science and Technology of China (USTC) in 1997, and conducted his postdoctoral work at Lawrence Berkeley National Laboratory and Sandia National Laboratories from 1998 to 2003. He was a professor at National Synchrotron Radiation Laboratory, USTC during 2003-2014. He moved to SJTU in 2015. His research interests include the development of mass spectrometry, laser spectroscopy and their applications in combustion and energy research.

Prof. Qi has co-authored more than 260 peer-reviewed journal papers. He was elected as a fellow of American Physical Society in 2012, a fellow of the Combustion Institute in 2018. He is a recipient of the USTC President Award for Outstanding Research in 2011, the National Award for Natural Sciences of China in 2018, the Humboldt Research Award in 2021, and Shanghai Science and Technology Elite Award in 2022. He gave a plenary lecture on the 34^th International Symposium on Combustion. He serves as Secretary for Section Affairs of the Combustion Institute since 2016. He was a Program Co-Chair of the 38^th International Symposium on Combustion. He is co-Editor-in-Chief of Applications in Energy and Combustion Science. He served or currently serves as a member of the Editorial Board of journals including Progress in Energy and Combustion Science, International Journal of Chemical Kinetics, Combustion and Flame, Proceedings of the Combustion Institute, Review of Scientific Instruments etc.

Reliable and predictable combustion model can help us to understand the combustion process deeply, and potentially help us to design higher-performance engines, increase combustion efficiency and reduce harmful emissions. However, the development of combustion model is badly relied on the advances of experimental and diagnostic methods. In this talk, basic experimental and diagnostic methods will be introduced. Some recent results will be presented with vacuum ultraviolet (VUV) photoionization mass spectrometry. Furthermore, the techniques can be applied in the detection of gas-phase products of heterogeneous reactions including catalysis reaction, biomass pyrolysis etc. And some recently built laser diagnostics systems at our laboratory will be introduced for application in swirling turbulent flame. Finally we will report on two facilities under construction that will be used for study of combustion and energy: Hefei Advanced Light Facility (HALF) and High-temperature High-pressure Optical Platform for Energy Research (H²OPER).

Dr. Farooq received his Ph.D. in Mechanical Engineering from Stanford University in 2010, and then joined King Abdullah University of Science and Technology (KAUST). He was promoted to the rank of full Professor in 2022. He is the principal investigator of the Chemical Kinetics and Laser Sensors Laboratory in the Clean Combustion Research Center (CCRC) at KAUST. His research interests are in the areas of energy, chemical kinetics, spectroscopy, and laser-based sensors. He has authored over 200 refereed journal articles and has given invited talks at a number of international conferences. At KAUST, he won the Distinguished Teaching Award, given to the best instructor over a period of two years. In 2019, Dr. Farooq was awarded the prestigious Hiroshi Tsuji Early Career Research Award by Elsevier and the Combustion Institute. In 2020, he received Research Excellence award by the Combustion Institute. He became a fellow of the Royal Society of Chemistry in 2022.

Sensors based on laser absorption spectroscopy (LAS) have achieved widespread usage in research and practical applications due to their simple architecture, ease of implementation, and field deployment. Recent years have witnessed strong emphasis on the mid-IR wavelength region of the electromagnetic spectrum due to the presence of strong fundamental vibrational bands of many species of interest, availability of laser systems and the opportunities to do sensitive as well as selective detection. Machine learning based methods are helping overcome the challenges of spectral interference and noise and are enabling simpler systems. This talk will briefly describe some of the recent ML-enabled mid-IR sensing work carried out at KAUST. This includes the measurements of a family of aromatic molecules, BTEX, for environmental monitoring by exploiting cavity-enhanced absorption and deep-neural networks. This work was then extended to multi-species measurements in shock tube chemical kinetic studies. Machine-learning methods were exploited to overcome non-linear blending in liquid fuel samples and to do multi-species quantification from noisy spectroscopic data. Spectral augmentation strategies were then employed to account for unknown interference in real-world applications.

Tim Huylebrouck earned his Bachelor of Engineering in Image Engineering Science from Cologne University of Applied Sciences, Tim Huylebrouck possesses a deep understanding of infrared imaging and detecting technology. He has dedicated his career to help customers finding the best solution to their infrared challenges, making significant contributions through practical insights. He has participated in panel discussions and conducted workshops at renowned conferences and events worldwide. His ability to simplify complex concepts and engage diverse audiences has earned him high praise and a loyal following. Moreover, Tim Huylebrouck has an impressive track record of collaborating with leading industry players, academic institutions, and research organizations. His collaborative mindset and interdisciplinary approach have fostered partnerships that have driven advancements in the understanding of typical physical behaviour of radiation in the infrared.

The pyroelectric receiver PR N°1 has been designed as a universal and well-tuned workhorse for metrology in the IR and THz. Design goal has been a WYSIWYG (what you see is what you get) functionality for straightforward data processing including scalability and repeatability based on a sufficient speed-performance combination. In our case, WYSIWYG does include the signal waveform, the signal linearity and the homogeneity over the active area. Consequently, the basic design did follow the “Bauhaus” principle of form follows function keeping in mind that:

• DLaTGS as “pyroelectric golden standard infrared material” cannot be used because of bad temperature behaviour, being hygroscopic and missing scalability.
• Instead, LiTaO₃ has been chosen as basic material since it is well established in industrial sensing already with proven linearity.
• LiTaO3 allows to use Ni/Cr nanorod as black absorber manufactured by PVD process. The identical technology is being used for HIS infrared emitters. It is scalable, robust, homogenous, and fast. 
• Thin material is needed to achieve the desired speed-performance combination.
• A micromachined chip can be manufactured by ion beam etching, i.e., a thin membrane is etched into the bulk material. This is a precise method, and it allows to place the bond wires at the frame leaving the active area untouched. The chip will be assembled by using 4 flexible posts for vibration dampening.
• The active element is operated in current mode which allows for a wide plateau where the signal is independent of frequency. A special amplifier needs to be developed for optimum trade-off between performance, speed, and minimum signal distortion.
• Current mode operation is more consistent at high temperatures.
• Eventually we found out, that a sweet spot is achieved by using a 2x2 mm² active element with 6 µm membrane thickness and an amplifier bandwidth of 8 kHz.   

The typical D* is 2 x 10⁸ Jones at 1 kHz. This means that the performance of typical uncooled or TE-cooled longwave IR semiconductor devices is within reach (at a slower speed). Beyond appr. 12 µm there are no longer any TE cooled good semiconductor devices available and the PR N°1 takes over. Linearity has been proven to be within +/- 1 % over 4 decades. This has been measured by a double-slit superposition method and will be explained in detail at the presentation. The accuracy of the measurement setup is estimated to be within 0.5 %. Spot scanning of the receiver is under work. Results will be shown at the presentation.

A well-tuned universal linear and homogenous IR and THz receiver has been designed and built. We expect that it will boost the “People´s FTIR”.    

Yong Yan is a  Professor of Electronic Instrumentation and Director of Innovation at the School of Engineering, University of Kent, U.K. He received the B.Eng. and M.Sc. degrees in instrumentation and control engineering from Tsinghua University, China in 1985 and 1988, respectively, and the Ph.D. degree in flow measurement from University of Teesside, U.K., in 1992. His research interests include sensors, instrumentation, measurement and condition monitoring. He has published over 220 papers in peer reviewed journals with an h-index of 51 and 10,000 citations. In recognition of his contributions to sooids flow metering and burner flame imaging, he was named an IEEE Fellow in 2011 and elected as a Fellow of the Royal Academy of Engineering in 2020. He was awarded the gold medal in 2020 by IEEE Transactions on Instrumentation and Measurement as the most published author of all time from the U.K. He has been an Editor of the Measurement journal since 2018 and Vice Chairperson of the IMEKO TC 20 Measurement of Energy and Related Quantities since 2023.

It is essential to measure the mass flow rate of CO2 for purposes of accounting, emissions trading and CCS system control. It is also important to detect CO2 leakage from transportation pipelines and storage facilities for safety and environmental purposes. However, significant changes in physical properties of CO2 (gas, liquid, two-phase or supercritical) mean that CO2 flows are complex in nature and difficult to measurement. Meanwhile, there are very few calibration facilities that can be used under CCS conditions. The presentation will introduce the challenges in this area of research and report the recent advance in developing measurement techniques for the mass flow metering and leakage detection of CO2 under CCS conditions. In particular, Coriolis flow metering techniques in conjunction with machine learning algorithms that are applied to achieve the mass flow metering of single-phase gas or liquid and gas/liquid two-phase flow under CCS conditions will be presented. Recent experimental work in applying acoustic, pressure and temperature transducers incorporating machine learning techniques for CO2 leakage detection will be reported. Experiences in the design and operation of a CO2 flow test platform under CCS conditions will also be presented.

Other projects in the area of energy measurement will also be introduced. These  include the mass flow measurement of pulverized fuel (biomass/coal), on-line fuel particle sizing, flame stability monitoring, and structure health monitoring of wind turbines.

Ge Guo received the B.Eng. degree in measurement and control technology and instrumentation and the M.Sc. degree in measurement technology and automatic devices from North China Electric Power University, Beijing, China, in 2016 and 2019, respectively. She is a postgraduate student studying for her Ph.D. degree in measurement technology and instrumentation at North China Electric Power University, Beijing, China. She is under the supervision of Prof. Yong Yan, a Fellow of the Royal Academy of Engineering and an IEEE Fellow, in the Centre for Multiphase Flow and Combustion Process Monitoring. Her current research interests include measurement of moisture and temperature distribution in biomass fuels through capacitive and acoustic tomography. This research is funded by the National Natural Science Foundation of China (No. 61973115). She participated in IEEE International Instrumentation and Measurement Technology Conference 2023.

As a substitute for traditional fossil fuels, biomass is widely used to generate electricity and heat. Due to biological metabolic reactions, exothermic chemical reactions and heat-producing physical processes, self-heating and spontaneous combustion of biomass fuels are important issues related to the safe operation of biomass-fired power plants. In order to acquire timely and reliable temperature information about biomass fuels and hence minimize fire risks, it is essential to measure the temperature distribution of stored biomass in silos at power stations on an online continuous basis. However, existing instruments such as thermocouples and thermal imaging systems, are not suitable for measuring the internal temperature distribution of stored biomass. This paper presents a proposed measurement system, based on acoustic sensors coupled with tomographic reconstruction algorithms, to measure the temperature distribution of biomass stored in a silo. Meanwhile, low-frequency acoustic sensing and cross-correlation signal processing techniques are combined to measure the temperature and its distribution. An acoustic signal with a frequency of 200-1500 Hz is generated and transmitted through stored biomass. The flight time of swept-frequency sound waves between the two acoustic sensors is obtained through correlation signal processing. Tomographic reconstruction algorithms are applied to obtain biomass temperature and its distribution. The arrangement of acoustic sensors is shown in Fig. 1. Twelve acoustic sensors are installed on the outer wall of the silo. Wood pellets, which are widely used for power generation, are used as a test biomass fuel. Fig. 2 shows a typical temperature distribution in a wood pellet silo. The blue area represents wood pellets at ambient temperature. The high temperature is set to about 40℃ higher than the ambient temperature. The reconstructed temperature distribution of biomass is given in Fig. 3. As can be seen, areas above the ambient temperature in the silo are clearly seen in the reconstructed image. These experimental results indicate that acoustic tomography is effective for the temperature distribution measurement of stored biomass within a relative error of ±8%.

Keywords: Biomass, temperature distribution, acoustic tomography, image reconstruction.

Dr. Roy Hermanns (male) is senior Scientist at the Eindhoven University of Technology. He received his PhD in 2007 at the same university in the Netherlands on laminar burning velocities of methane-hydrogen-flames. After his PhD he started at OWI in 2007 in the area of numerical combustion research. He managed different kind of activities from scientific work to industry related research in the area of liquid fuel combustion and fuel processing on a national and European level. He is coordinated several EU projects among them Residue2Heat, IDEALFUEL and HELIOS. He stayed at IIT Madras (India) as a Short Term IGCS Visiting Professor. In 2019 he started as a Senior Scientist at the TU Eindhoven important building blocks of his research focus on the valorisation of the fundamental research, especially in the areas of metal energy carriers (zero emission energy carrier) and hydrogen combustion.

As widely acknowledged, it is mandatory to decarbonize our energy system. This requires not only major investments in solar and wind energy, but also in means to store energy from these fluctuating resources. Battery storage is not suitable for large-scale storage for many reasons including size and prize. Furthermore, hydrogen has a relatively low energy density, even under high pressure or cryogenic circumstances. A low-cost alternative with much higher energy density is metal powder; renewable electricity can be used to reduce metal oxide to metal, that can be stored under ambient conditions and combusted (=oxidised) whenever energy is needed, providing fully renewable heat.

The fundamental understanding of metal powder as a dense energy carrier for a truly circular and renewable Zero-Carbon Energy Storage and Conversion System is still largely lacking. A multidisciplinary approach to establish a sound fundamental knowledge basis for this breakthrough concept is needed. In this presentation various aspects of the oxidation-reduction cycles will be shown. As well among them the particle changes after each cycle and the change of the laminar burning velocity of a hybrid methane-air flame.

Christian Hasse is professor at Darmstadt University of Technology (Technische Universität Darmstadt) and since 2017 director of the Institute for the Simulation of Reactive Thermo-Fluid Systems (www.stfs.tu-darmstadt.de). . He is elected Fellow of the Combustion Institute for his contributions on turbulent combustion, solid fuel combustion, multi-phase flow and soot formation. From 2010-2017 he was full professor at the Technische Universität Bergakademie Freiberg. From 2004-2010 he worked at BMW in engine development and exhaust aftertreatment, after he received his doctorate at RWTH Aachen University in 2004 (supervisor: Norbert Peters). He has supervised successfully more than 24 PhD students and currently 30 PhD students and post-docs are working in his group in Darmstadt. He is co-organizer of several scientific workshops and conferences, including the Workshop on Measurement and Simulation of Coal and Biomass Conversion (CBC) and the International Workshop on Measurement and Computation of Turbulent Flames (TNF). He is a member of the editorial board of the International Journal of Engine Research and Applications in Energy and Combustion Science and Associate Editor of the Proceedings of the Combustion Institute. He has published over 220 peer-reviewed papers in archival journals (included invited review articles) and is reviewer for more than 20 scientific journals and several national and international funding agencies.

His main research interests are modeling and simulation of reactive and non-reactive flows, including flamelet modeling, solid fuel combustion and gasification, turbulent mixing dynamics, multi-component spraying and evaporation, engine combustion, pollutant formation, population balance modeling and exhaust gas cleaning. His main fields of application are combustion and chemical process engineering. For these topics, his group has developed a number of high-fidelity software applications that are deployed national Tier-2 and European Tier-0/1 supercomputers.

The transformation of energy systems to achieve climate neutrality is one of the most pressing challenges of our time. In that context, metal fuels are emerging as a zero-carbon, high-energy density replacement for fossil fuels due to their availability and recyclability using renewable energy. Iron in particular is a promising option for a carbon-free cycle. Iron is non-toxic, safe to transport, easy to store, abundant, and in principle can be recycled an unlimited number of times.

In this presentation, iron as a metal fuel is first introduced as a recyclable chemical energy carrier for a carbon-free circular economy. During the reduction of iron oxides, energy from renewable sources such as wind and solar is stored. This energy is released again through oxidation and can be used as high-temperature process heat or for the generation of electricity.
This is followed by selected experimental and numerical results on the combustion physics of iron. First, the oxidation of single iron particles is presented, and the different phases of ignition and combustion are discussed with a special focus on the coupling of gas phase transport with the condensed phase kinetics. Next, canonical polydisperse iron-air flames, from which typical combustion characteristics such as the flame speed can be deduced, are studied. Going towards multidimensional flames, experimental and numerical results for a laminar self-sustained Bunsen-type jet flames are presented. The reaction zone structure and the reaction front speed are analyzed. The need for well-controlled and well-characterized experimental conditions to reduce uncertainties is demonstrated by comparison to simulation results. Finally, results for turbulent iron-air flames are presented.

After obtaining a PhD in Mechanical Engineering in 2005, he worked on combustion phenomena in IC engines. He obtained a Professor position at University of Orléans in 2014. There he developed canonical set-ups to experimentally investigate gaseous and multiphasic combustion processes. He is active for 10 years in the research of new energy carriers, such as metal fuels. He has co-authored more than 100 papers and has advised more than 20 PhD students. He is a member of the Editorial Board for Combustion and Flame and was awarded as Fellow of the Combustion Institute in 2022. He is the head of a Research Federation focused on energy and of the Energetics Department at University of Orléans. He has led several national and international projects in the field.

What if small metal particles were the future of energy? The possibility to use metal powder to store energy from intermittent renewable energy sources arises naturally as a close to zero GHG emission well-to-wheel specific reduction process can be performed from the oxidized metal particulates using concentrated solar energy. Micron-sized metal powders are easily transportable and have a practically unlimited shelf life when protected from humidity in hermetically-sealed containers. Combustion of these metal particles releases a large amount of energy and has the advantage of not emitting carbon dioxide. These particles, burning in air or other oxidizers, produce metal oxides which can then be regenerated using solar energy. This cycle energy production / recycling can make it possible to store energy produced with renewable energy in a secure and sustainable way, so that it can be used where and when it is needed. The proposed talk describes the work undergone on this original and promising concept. It is part of a disruptive technology to solve the problem of global warming in the long term.

Metal particles are likely to be used as a steady power source such as industrial burners. It appears that the durable stabilization of this type of flame requires a good control of the suspension of the particles. When burning aluminum, a very large part (>50%) of the energy is radiated from the reaction zone to the surrounding medium. This property, which results from the very high temperatures involved, will directly determine the heat recovery unit to be used. The oxides produced are heavier and bulkier than the initial particles, which may complicate their post-combustion storage. Their filtration remains quite easy, despite their nanometric size, due to their strong propensity to agglomerate. Almost complete filtration is achievable with conventional filtration systems. The formation of nitrogen oxides is favoured by high temperatures and an excess of oxygen. One solution to limit their concentration at the exhaust is to work close to stoichiometry.

Modern refrigerant design faces challenges in simultaneously improving efficiency, reducing global warming potential (GWP), and ensuring safe handling in practical applications. Commonly used hydrofluorocarbon (HFC) refrigerants have unsaturated molecules or fewer fluorine atoms, which are replaced by hydrogen, reducing their atmospheric lifetime due to their increased reactivity with oxygen. As a result, they are mildly flammable. The laminar flame speed SL,u determines their hazardous fire potential. Refrigerants with a low flame speed are less dangerous, but measuring slow flame propagation is challenging due to the influence of gravity and radiation on combustion. The combustion behaviour is comparable to conventional fuels burning under ultra-lean/rich or highly diluted conditions. Experiments must be conducted under microgravity conditions to isolate the effect of radiation from gravity. Recent achievements in the methodology of flame speed acquisition under microgravity conditions are presented. Experimental data were obtained during parabolic flight campaigns on the Airbus Zero-G, Bordeaux, France, and in the drop tower at the ZARM, Bremen, Germany. The impact of radiation is discussed, and recommendations for accurate flame speed measurements are suggested.

Dr. Alaa Hamadi earned her PhD in Energy from University of Orleans, France , Alaa Hamadi possesses a deep understanding of the kinetics involved in the formation of polycyclic aromatic hydrocarbons during the pyrolysis of  different fuel components and mixtures. Currently, she is working as post-doctoral researcher on understanding the combustion fundamentals such as unstretched laminar flame speed and Markstein length of ammonia and hydrogen based mixtures.

Laminar flame speed refers to the propagation rate of the normal flame front relative to the unburned mixture. This parameter is of great importance in the study of combustion processes due to its wide-ranging applications across various fields. It  plays a pivotal role in optimizing combustion efficiency and performance in engines and turbines, leading to reduced fuel consumption and enhanced energy efficiency. Additionally, its impact on combustion timing plays a vital role in curbing the formation of pollutants like nitrogen oxides and particulate matter, fostering cleaner and more environmentally friendly combustion processes. Its significance extends to safety, as understanding how quickly flames can propagate is essential for designing secure industrial systems, preventing undesirable phenomena like engine knock or detonation, and ensuring the durability of combustion systems. Hence, it is a fundamental parameter in combustion modeling that aids researchers in predicting and analyzing combustion behaviors under diverse conditions, and a critical factor in alternative fuel development that guides the selection and optimization of fuels for various applications. Consequently, it is crucial to have accurate laminar flame speed measurements. Nonetheless, various factors influence the precision of laminar flame speed, leading to considerable discrepancies in data within the literature. One of these factors pertains to the influence of the extrapolated flame radius domain on the derived laminar flame speed. A current study on oxygen-enriched ammonia demonstrates that larger domains negate this domain-related effect. The second aspect involves radiative losses. The intensity and spectral distribution of flame radiation are closely tied to factors such as flame dimensions, shape, mixture composition as well as local pressure and temperature. Notably, there is a lack of documented investigations into experimentally determined heat losses. This is where the Fast Absolute Infra-Red Sensor (FAIRS), developed and provisionally tested by Idir et al. [1], becomes relevant. Radiative heat losses have been quantified using a blend of hydrogen and methane, resulting in an estimated loss fraction of 1% attributed to radiation.

[1]         Idir M, Rayaleh AM, De Sousa Meneses D, Semmar N, Chaumeix N. Absolute and real time experimental radiative loss measurements of spherical expanding free flames: FAIRS (Fast Absolute InfraRed Sensor)-An innovative technique. Rev Sci Instrum 2022;93:095103. doi.org/10.1063/5.0101519.

Oliver Büker is a senior researcher at RISE Research Institutes of Sweden. He received his Ph.D. in Chemical and Process Engineering from the Technical University of Berlin in 2010. This was followed by two years as a postdoctoral researcher at PTB, the NMI of the Federal Republic of Germany, working mainly on flow measurement with a focus on laser optical measurement techniques.

In 2012 he joined RISE where he works in the division Safety and Transport in the department Measurement Science and Technology which includes the National Metrology Institute (NMI) of Sweden for the unit volume, flow and density. Oliver has two decades of practical and theoretical experience from national, European and international projects related to flow, chemistry and energy measurements.

He is the Swedish representative in the EURAMET Technical Committee for Flow (TC-Flow), the BIPM CCM Working Group on Fluid Flow (WGFF), the BIPM CCM Working Group on Density and Viscosity (WGDV). He is an expert in the European Metrology Network (EMN) for Energy Gases and a member of the IMEKO TC9 Flow Measurement.

Hydrogen can make a significant contribution to reducing emissions from the transport sector as it is particularly well suited as a fuel for long‑haul heavy‑duty vehicles. The uptake of hydrogen for heavy‑duty transport requires further standardisation to support Europe’s green energy future. Sampling systems and methods have already been developed for use at hydrogen refuelling stations for light‑duty vehicles, however there is a lack of technical evidence for heavy‑duty vehicles.

With the growing interest in the use of hydrogen and fuel cells in medium and heavy duty applications, the need for dedicated standards for these applications has increased. Currently, the number of hydrogen-powered buses, trucks and trains in Europe is around 500 units, but this is expected to grow at a very high rate. At least 60,000 hydrogen-powered trucks are expected to be in operation by 2030, requiring a large infrastructure of truck-friendly hydrogen refuelling stations.

Hydrogen-powered vehicles require extremely pure hydrogen, as some contaminants, even at very low levels, can reduce the performance of the fuel cell. Previous metrology projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment. However, the reliability of a measurement is inextricably linked to the representativeness and reliability of the sampling itself. Poor sampling can lead to a fleet of HD vehicles being damaged. Furthermore, standardisation is required as the heavy-duty hydrogen refuelling station network will be shared between operators. Also, sampling practices should not be a source of quality variation within the emerging network.

An overview of the EURAMET European Partnership on Metrology project 22NMR03 “Metrology for standardisation of hydrogen fuel sampling for heavy duty hydrogen transport” (MetHyTrucks), which started in June 2023, is presented. The project aims to provide the necessary evidence for the standardisation of hydrogen fuel sampling for heavy‑duty applications. This will include the development of dedicated contaminant sampling systems for both gaseous species and particulate matter, methodologies for the validation of sampling methods, guidelines for the evaluation of sampling representativeness, uncertainty budgets, safety considerations and venting protocols.

Acceptance of hydrogen fuel will only be achieved by minimising operational problems, which in turn is achieved through confidence and assurance that the required quality will be maintained. As acceptance of hydrogen-powered vehicles increases, these vehicles will increasingly be seen as normal road vehicles rather than prototypes or small fleets. Social acceptance of hydrogen as a fuel is essential for the energy transition towards a greener society.

Dr. Markus Köhler earned his PhD in chemistry at the University of Bielefeld from Prof. Dr. Kohse-Höinghaus. He started his career as a Post-Doc at the DLR Institute of Combustion Technology in Stuttgart 2009 in the field of laser diagnostics to investigate soot formation. Now as head of the department “Chemical Kinetics and Analytics”, a deep understanding of alternative fuels and pollutant formation is the main driving force behind his work. Markus Köhler has dedicated his career in discovering the impact of molecular chemical compositions on physical properties, pollutant formations and exhaust gas emissions. By this, fuel design strategies and technical fuel assessment are systematically enabled for novel fuels. The fundamental approach includes chemical analysis, investigation of kinetic combustion reaction networks, and advanced pollutant detection techniques to enable the development of novel alternative fuels not only mimicking fossil fuels, but optimize future energy carriers. Numerus skillfully weaved large-scale projects on national and international level provide significant progress in fuel development through by combining fundamental research with technical applications. With renowned partners from industry, research institutes and universities, Dr. Markus Köhler has garnered widespread international recognition for his exceptional achievements. This includes the NASA group achievement award for large scale field measurement campaigns, combining detailed analytical chemistry with particle emission measurements from technical jet engines.

Reducing the man-made carbon footprint is a worldwide challenge and one uniting global goal in our modern society. Sustainable aviation fuels (SAFs) are on the brink on replacing fossil fuels in the years to come. SAFs are produced from renewable feedstocks that have to follow strong environmental, social, and economic (circular) criteria. A strict ecological balance by avoiding depletion of natural resources and by not contributing to climate change is essential in the strategy to work. Based on the feedstocks used (bio-based, waste-based, or Power-2-X processes) and based also on the production synthesis processes, SAFs’ composition can be close to a chemical copy of conventional crude-oil based Jet A-1/Jet A or hydrocarbons that are not found in conventional jet fuel. Understanding the impact of the chemical composition or properties, assessing and optimizing fuels, while taken constraints such as compatibility, and most of all in aviation safety, regulated by ASTM approvals into account, is the main scientific goal of our technical fuel assessment strategies.

From a chemical point of view, the final composition can differ in its total number of species, in its distribution of species within the kerosene cut, and/or in the species’ chemical structures (e.g. different isomers) with respect to Jet A-1/Jet A. Utilizing such fuels in commercial aviation started first with the development of a robust approval process. The assessment of SAF candidates is not based on their chemical composition but rather on their properties and their performance with respect to physical and chemical sub-processes, which are key to the overall safety.

Understanding the impact of fuels on safe operation and handling, then on engine performance and emissions, and ultimately the environmental impact and climate forcing of aviation is key of the presented research. It is important to investigate and fully comprehend the effect of fuel composition on its physical and chemical properties and further on the sub-processes occurring in the combustion system. An overview is given on the chemical analytics, the experiments, the diagnostics and modeling methods, as well as real system in real world measurement campaigns, which enabled us to analyze these effects. Finally, the knowledge regarding these effects become the building blocks for proper fuel design.

Dr. Guangyu Dong is currently an associate professor in Tongji University (2017-now), he earned his Doctorate Degree from Tongji University in 2010, and worked as a research fellow in Sir Harry Ricardo Laboratories during 2013-2017. Guangyu possesses a deep understanding of engine combustion research and flame multi-physics analysis. He has dedicated his career to engine combustion diagnostics and flame plasma physics, making significant contributions through his research, innovation, and practical insights. He has been invited to give oral presentation in international combustion symposium for 3 times, underscoring his expertise and influence in the field. Based on his achievements, over 30 papers have been published in peer-reviewed journals such as Proceedings of Combustion Institute and Combustion and Flame. Guangyu has an impressive track record of collaborating with leading industry players, academic institutions, and research organizations, he participated in more than10 research projects both domestically and internationally. His collaborative mindset and interdisciplinary approach have fostered partnerships that have driven advancements in internal combustion engine research domain.

In order to achieve the carbon neutrality of powertrain systems, especially in the ground transport section, the heavy-duty vehicles fueled with ammonia-hydrogen mixtures is believed to be promising as both high power density and zero emission performance can be guaranteed via such a technology. Therefore, interdisciplinary research on the core scientific issues regarding the ammonia-hydrogen dual fuel powertrain system is conducted in the past few years. This topic is focus on the characteristics and formatting mechanism of ammonia-hydrogen combustion pollutants. Firstly, the background of the current research project is introduced, then a literature review of the ammonia-hydrogen fuel development is conducted. Base on previous studies, the combustion chemical reaction kinetics, the emission monitoring technologies and the aftertreatment control strategy of the powertrain system are analyzed to solve the problems such as difficult ignition, slow combustion, and complex pollutants aftertreatment methodology. Finally, a potential technique route for minimizing the combustion pollutants from the ammonia-hydrogen combustion is demonstrated, and then be applied to develop the future heavy-duty vehicles with zero emissions.

Mr. Pedisetti Kumar Sai Tejes is a research scholar in the Department of Mechanical Engineering at NIT Rourkela since 2021. He completed his M.tech in Thermal engineering (2017) from K. L University, Andhra Pradesh, and his B.Tech (2015) from JNTU Kakinada. He worked as a Project Scientific Assistant at the National Institute of Ocean Technology, Chennai (2019-2021) in the design, development, and construction of low-temperature thermal desalination plants (LTTDs)in Lakshadweep, India. He is currently working on the design and development of hollow fiber membrane-based liquid desiccant dehumidification/desalination systems. In his Ph.D. career so far he coauthored 4 SCI journals,  authored 2 SCI journals attended 10 international and national conferences. He delivered a training session talk on the Implementation of Machine Learning and Artificial Neural Networks for thermal systems in SERB- Karyashala in NIT Rourkela. Additionally, he served as the Student Activities Chair and CWC member for the ISHRAE Bhubaneswar Sub-Chapter from 2022-2023.

The demand for energy-efficient and sustainable air conditioning systems has led to the development of liquid desiccant dehumidification systems, which offer numerous advantages over conventional cooling technologies. In order to optimize the performance of these systems, it is crucial to accurately measure and evaluate the ventilation efficiency of the system. This study presents a novel approach to assess the ventilation efficiency in a novel three-fluid operated hollow fiber membrane-based liquid desiccant dehumidification system (TFLD) using CO₂ tracer gas test. The liquid desiccant used is Lithium chloride (LiCl) and the hydrophobic membrane contactors are made of Polyvinylidene fluoride (PVDF). The experiment involves injecting a controlled constant amount of 4200 ppm CO₂ gas into the varying dehumidified air stream of 0.25 kg/s to 0.51 kg/s, relative humidity (RH) and temperature of dehumidified air from 20% to 30% and 20 ˚C to 25 ˚C into a closed room. The measurements are carried out under different operating conditions to evaluate the system performance by monitoring its concentration at different locations by strategically placed sensors to capture the CO₂ concentration levels every 10 seconds. The air exchange rate is considered as a performance parameter. Further, from the results it is observed that the maximum air exchange rate is obtained to be 6.25 and CO₂ concentration is reduced to 950 ppm at 0.51kg/s airflow rate, 20% RH, and 21˚C. Hence, The CO₂ tracer gas test proved to be a reliable and cost-effective method for evaluating ventilation efficiency in a hollow fiber membrane-based liquid desiccant dehumidification system. Furthermore, the findings of this study contribute to the overall understanding of system dynamics and support the development of more efficient and sustainable air conditioning technologies. The proposed methodology can serve as a valuable tool for system designers, engineers, and researchers involved in the development and optimization of liquid desiccant-based air conditioning systems.