Chemical Energy Of Hydrogen Research Articles

Alternative proton exchange membrane based on a bicomponent anionic nanocellulose system

As integral parts of fuel cells, polymer electrolyte membranes (PEM) facilitate the conversion of hydrogen's chemical energy into electricity and water. Unfortunately, commercial PEMs are associated with high costs, limited durability, variable electrochemical performance and are based on perfluorinated polymers that persist in the environment. Nanocellulose-based PEMs have emerged as alternative options given their renewability, thermal and mechanical stability, low-cost, and hydrophilicity. These PEMs take advantage of the anionic nature of most nanocelluloses, as well as their facile modification with conductive functional groups, for instance, to endow ionic and electron conductivity. Herein, we incorporated for the first time two nanocellulose types, TEMPO-oxidized and sulfonated, to produce a fully bio-based PEM and studied their contribution separately and when mixed in a PEM matrix. Sulfonated nanocellulose-based PEMs are shown to perform similarly to commercial and bio-based membranes, demonstrating good thermal-oxidative stability (up to 190 °C), mechanical robustness (Young's modulus as high as 1.15 GPa and storage moduli >13 GPa), and high moisture-uptake capacity (ca. 6330 % after 48 h). The introduced nanocellulose membranes are shown as promising materials for proton-exchange material applications, as required in fuel cells.

Analysis of Power Consumption on BOP System in a Fuel Cell Electric Bus According to the Fuel Cell Load Range

The proton exchange membrane fuel cell (PEMFC) in a fuel cell electric bus (FCEB) converts hydrogen's chemical energy into electrical energy. The fuel cell system comprises a fuel cell stack and a balance of plant (BOP) system, which efficiently controls the stack. Fuel cell and battery are sensitive to operational temperature, which directly impacts performance, lifespan, and safety. Therefore, a thermal management system (TMS) is necessary to maintain an appropriate temperature by dissipating the heat generated by the fuel cell and battery. In this study, the exponential or quadratic relationships between the power consumption of the major components of an FCEB and various factors, such as temperature and flow rate influencing the operational behavior and control of the components, were analyzed based on the results of a dynamometer vehicle test. Additionally, the vehicle's energy flow was calculated under different fuel cell load conditions. When the fuel cell operated at 56.3 kW, TMS power was 6.6 times higher than at 20 kW. At full load, under 90 kW, it increased to 17.4 times higher. The rise in fuel cell load correlated with higher heat generation, resulting in a significant increase in power consumption for both the radiator fan and coolant pump.

Critical investigation of microchannel design effect on thermal performances of a PEM fuel cell

A major challenge for improving the characteristics of fuel cells is to obtain uniform tempera-ture distribution during its operation, in which a major part of hydrogen chemical energy is converted to heat. If not properly exhausted, this exothermic chemical reaction causes over-heating in the polymer electrolyte membrane fuel cells (PEMFCs), leading to a reduction in their performance. Hence, analyzing different techniques for PEMFCs cooling may be nec-essary for this kind of energy systems. In this study, four microchannel design effect on alu-minum oxide (Al2O3) nanofluids thermal behavior in cooling plates with 1400×1800 mm2 was investigated using computational fluid dynamic (CFD) simulation. The performances of proposed microchannel designs were evaluated in terms of maximum and uniformity tem-perature. The suggested study has been validated by available published results from previous research studies. The obtained results depicted that the maximum temperatures have been 305.3K and 305.5K for S- character flow field and two stages coolant flow field microchannel designs, respectively. The results revealed that the multi-flow plate designs might greatly en-hance the performance of PEMFCs in terms of temperature distribution in the cooling plate when compared to standard flow field designs. Another important finding was that the two stages microchannel and S-design are more thermal stable compared with other microchan-nels.

Neutron Nanomediators for Non-Invasive Temperature Mapping of Fuel Cells

Polymer electrolyte fuel cells (PEFCs) have gained significant attention in the past century for their ability to convert hydrogen chemical energy into electrical energy. However, the technology still requires refinement due to losses in polarization, ohmic resistance, and mass transport that result in heat generation, negatively affecting the device water management and durability. To better understand these processes, researchers initiate studies to improve knowledge of the temperature at the cell structure core. However, current methods using micro-thermocouples [1] are highly invasive, impeding cell operation and limiting data accuracy.The project aims to overcome the latter problem using ferromagnetic nanoparticles for non-invasive temperature mapping on these devices. A key part of this novel method is the application of Neutron Imaging through a polarized beam [2], which allows to detection of the temperature distribution on the surrounding nanosensors. The dispersed ferromagnetic nanomediators, in these conditions, depolarize the incoming neutron beam due to the random magnetic field produced by the nanoparticles themselves. Furthermore, as the temperature rises toward the Curie temperature (Tc), the nanosensors tend to lose their magnetic preferential orientation, influencing the neutron beam polarization gradually less as the ambient temperature increases.This project includes identifying a suitable material, synthesizing nanoparticles through solution techniques [3], and performing physical and magnetic ex-situ characterizations. By dispersing them in Polytetrafluoroethylene micro-powders, nickel, iron, and Nd2Fe14B alloys were initially studied at different concentrations, grain sizes, and magnetic environments, showing promising signal detection (η) and absolute thermal variation (Δη) results.

Efficient NH3-Tolerant Nickel-Based Hydrogen Oxidation Catalyst for Anion Exchange Membrane Fuel Cells.

Converting hydrogen chemical energy into electrical energy by fuel cells offers high efficiencies and environmental advantages, but ultrapure hydrogen (over 99.97%) is required; otherwise, the electrode catalysts, typically platinum on carbon (Pt/C), will be poisoned by impurity gases such as ammonia (NH3). Here we demonstrate remarkable NH3 resistivity over a nickel-molybdenum alloy (MoNi4) modulated by chromium (Cr) dopants. The resultant Cr-MoNi4 exhibits high activity toward alkaline hydrogen oxidation and can undergo 10,000 cycles without apparent activity decay in the presence of 2 ppm of NH3. Furthermore, a fuel cell assembled with this catalyst retains 95% of the initial peak power density even when NH3 (10 ppm)/H2 was fed, whereas the power output reduces to 61% of the initial value for the Pt/C catalyst. Experimental and theoretical studies reveal that the Cr modifier not only creates electron-rich states that restrain lone-pair electron donation but also downshifts the d-band center to suppress d-electron back-donation, synergistically weakening NH3 adsorption.

Investigation on auto-ignition and chemical energy release characteristics of pilot hydrogen in supersonic combustion flow

This study investigates auto-ignition and heat release characteristics of pilot hydrogen chemical energy in a scramjet combustor equipped with a single cavity. Experiments are conducted in a direct-connected facility simulating Mach 6.0 flight conditions with a total temperature of 1350 K and total pressure of 1.75 MPa. Data are obtained from schlieren imaging, hydroxyl planar laser-induced fluorescence, flame emission, and 10-kHz static pressure transducers. The present investigation extends the pilot hydrogen ignition delay experimental dataset and clarifies the instabilities present in the ignition process. The results show that the supersonic internal flow of a confined cavity exhibits self-oscillating behavior with a dominant frequency of approximately 141.3 Hz. The primary chemical reaction occurs at mid-cavity, where the chemical energy of the pilot hydrogen begins to be converted into heat energy, then approaches the cavity ramp before finally being distributed across the whole cavity. The combustion mode is the cavity-stabilized scramjet mode. The distribution of hydroxyl radicals varies significantly because the combustion in the cavity is unsteady. The ignition delay time increases as the injection pressure rises. However, an injection pressure of 4.0 MPa produces an ignition delay of 24.7 ms, which is apparently shorter than the delay under an injection pressure of 3.5 MPa and similar to that under an injection pressure of 3.0 MPa. The injection of pilot hydrogen under high pressures induces greater heat release and more intense blockage effects, thus enhancing the probability of successful ignition and stable combustion.

Critical investigation of microchannel design effect on thermal performances of a pem fuel cell

A major challenge for improving the characteristics of fuel cells is to obtain uniform tempera-ture distribution during its operation, in which a major part of hydrogen chemical energy is converted to heat. If not properly exhausted, this exothermic chemical reaction causes overheat-ing in the polymer electrolyte membrane fuel cells (PEMFCs), leading to a reduction in their performance. Hence, analyzing different techniques for PEMFCs cooling may be necessary for this kind of energy systems. In this study, four microchannel design effect on aluminum oxide (Al2O3) nanofluids thermal behavior in cooling plates with 1400×1800 mm2 was investigated using computational fluid dynamic (CFD) simulation. The performances of proposed micro-channel designs were evaluated in terms of maximum and uniformity temperature. The sug-gested study has been validated by available published results from previous research studies. The obtained results depicted that the maximum temperatures have been 305.3K and 305.5K for S- character flow field and two stages coolant flow field microchannel designs, respectively. The results revealed that the multi-flow plate designs might greatly enhance the performance of PEMFCs in terms of temperature distribution in the cooling plate when compared to standard flow field designs. Another important finding was that the two stages microchannel and S-de-sign are more thermal stable compared with other microchannels.

A cascade energy cycle based on solid oxide fuel cell with electric energy storage option

ABSTRACT Recently, solid oxide fuel cells (SOFCs) have been known as a popular technology due to their versatility in fuel intake, carbon-free process, and scalability in various applications. Besides that, the utilization of their exhaust heat in cascade cycles improves the process behavior by increasing the energy production rate. From the literature, gas turbines (GTs) are typically utilized as the downstream cycle of SOFCs. However, thermionic generators (TIGs) can be integrated with SOFCs in order to utilization the released heat to produce more electric power. TIGs can be more reliable and stable compared to GTs. Moreover, TIG’s environmental pollution is significantly lower than GTs. On the other hand, thermoelectric generators (TEGs) are devices that require lower grade heat compared to TIGs. In this study, a conceptual-evaluation study of a SOFC-based cascade cycle integrated with TIG and TEG is presented and discussed under the effective parameters. The introduced cascade system is able to produce electric power to meet consumer demand. In this regard, by using SOFC, the chemical energy of hydrogen is converted into electric power and excess heat under electrochemical reactions. By directing waste heat first to TIG and then to TEG, more electric power is yielded during two processes. Further, when the consumer does not need electricity, electric energy is stored by the hybrid pumped hydro and compressed air system (PHCAS) for later utilization. Therefore, the energy structure introduced in the current article suggests a new arrangement and configuration for electrical energy generation and storage. The outcomes of simulation revealed that the considered structure can produce nearly 3.9 kWh of electric energy per day. The energy efficiency of the system in such a context is almost 69.6%. Moreover, 16.12 moles of hydrogen gas (as fuel of SOFC) are required per hour. Additionally, PHCAS with a volume of nearly 2.98 m3 is required to store electrical energy. Also, improving the storage performance depends on the use of efficient storage equipment and setting the initial pressure in values close to the peak point.

Ionomer Optimization for Hydroxide-Exchange-Membrane Water Electrolyzers Operated with Distilled Water: A Modeling Study

The hydroxide-exchange-membrane water electrolyzer (HEMWE) is a promising means to store intermittent renewable energy in the form of hydrogen chemical energy. The hydroxide-exchange ionomer (HEI) in the gas-evolving electrodes and the hydroxide-exchange membrane (HEM) are key components of HEMWE. In this work, we simulate the cell and examine explicitly the impact of HEI and HEM properties with a focus on improving HEMWE performance when operated with distilled water (i.e., no supporting electrolyte). The tradeoff between the ionic conductivity gain and electrochemically active surface area (ECSA) loss is studied. For a constant catalyst loading, distributing more catalyst next to the HEM or making thinner but denser catalyst layer is beneficial for HEMWE performance. The results demonstrate that a higher water diffusion coefficient is desired for HEM to supply reactant water to the cathode. In contrast, a lower water diffusion coefficient is preferred for the cathode HEI to retain the water in the regions with high reaction rates. Overall, the findings provide important insights to optimizing HEI/HEM materials for improved HEMWE performance.

Solar and wind energy in Poland as power sources for electrolysis process - A review of studies and experimental methodology

The production of hydrogen is still a major challenge, due to the high costs and often also environmental burdens it generates. It is possible to produce hydrogen in emission-free way: e.g. using a process of electrolysis powered by renewable energy. The paper presents the concept of a research, experimental stand for the storage of renewable energy in the form of hydrogen chemical energy with the measurement methodology. The research involves the use of proton exchange membrane electrolysis technology, which is characterized by high efficiency and flexibility of energy extraction for the process of electrolysis from renewable sources. The system consist of PV panel, PEM electrolyzer, battery, programmable logic controller system and optional a wind turbine. Preliminary experimental tests results have shown that the electrolyzer can produce in average 158.1 cc/min of hydrogen with the average efficiency 69.87%.

Investigation on multifunctional Au/TiO2@n-octadecane microcapsules towards catalytic photoreforming hydrogen production and photothermal conversion

Combining solar energy utilization and hydrogen production is an ideal model for renewable energy development. Especially the conversion of broad-spectrum solar energy into chemical energy of hydrogen and thermal energy can enrich solar energy storage methods. Herein, novel multifunctional Au/TiO2@n-octadecane microcapsules with core-shell structure were design and synthesized by wet chemical reduction and electrostatic adsorption self-assembly methods for photothermal hydrogen production and thermal storage. The results showed that microencapsulation of photothermal catalysts could provide an effective reaction area and excellent dispersion stability, where hydrogen production and light to hydrogen efficiency were increased in the 43% and 0.3% respectively, compared to the nanoparticle suspension system. Based on the recorded temperature variations caused by the photothermal effect, the calculated photothermal conversion efficiency and specific absorption rate of Au/TiO2@n-octadecane was 25.01% and 277% higher than that of Au/TiO2 suspension. The proposed hydrogen production and thermal storage method via multifunctional microcapsules might shed some light on the study of improving full-spectrum energy conversion efficiency of solar energy.

Recent Progress of Transition Metal Phosphides for Photocatalytic Hydrogen Evolution.

Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO2 , CdS, g-C3 N4 , metal-organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large-scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H2 generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co-catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems.

Mathematical Modeling of Hydroxide-Exchange-Membrane Water Electrolyzer

Water electrolyzers can transform intermittent renewable energy like solar energy and wind energy into the chemical energy of hydrogen with zero greenhouse-gas emissions. The hydroxide-exchange membrane electrolyzer (HEME) combines the capability to produce pressurized hydrogen with the advantage of being able to use low or non-platinum group metal (PGM) electrocatalysts in the alkaline environment.1 Hydroxide salts, for example, KOH, are added to the HEME water feed on both anode and cathode to improve its performance. However, the specific mechanism of performance improvement still needs to be further understood. In addition, at high current densities, bubble evolution can result in mass-transport limitations, a less well studied phenomena. Mathematical modeling is ideal to explore these issues as it is cost and time efficient and can deconvolute the physics, processes, and observed phenomena and study the applied-voltage breakdown. In this work, we extend our previously developed 1D two-phase continuum model2 to study the varies processes in the HEME and provide insights on performance optimizations.First, the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) kinetics at different hydroxide concentrations have been studied by rotating disk electrodes (RDE) and implemented in the model. Then, the model is calibrated and validated against experimental HEME polarization curves for different KOH concentrations as a liquid electrolyte. The model clearly shows a performance increase with increasing KOH concentrations, which is consistent with the experimental results. The reduced ohmic resistance and increased electrochemical active surface area (ECSA) are the two main reasons for performance increase. The large amount of hydroxide in the liquid electrolyte not only helps to distribute the reactant hydroxide throughout the catalyst layer (CL), which reduces ohmic loss, but also enables reaction at the interface between the liquid electrolyte and electrocatalyst, which increases the ECSA. Applied-voltage breakdown demonstrates that the electrolyzer performance is dominated by anode kinetics and ohmic loss. A comparison with the DI water feed shows a more uniform current distribution in the anode CL when KOH is added, which indicates a higher utilization of the CL.Second, we present modeling on the effects of bubble coverage. As gas evolves, part of the ECSA is minimized due to bubble coverage. To account for this effect, an empirical relationship between the fractional bubble coverage and the current density is implemented in the model.3 The model shows this bubble coverage effect is more pronounced at large current densities with DI water feed. Acknowledgements This work was funded under the HydroGEN Consortium by the Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, of the U. S. Department of Energy under contract number DE-AC02-05CH11231. References R. Abbasi, B. P. Setzler, S. Lin, J. Wang, Y. Zhao, H. Xu, B. Pivovar, B. Tian, X. Chen, G. Wu and Y. Yan, 31, 1805876 (2019).L. N. Stanislaw, M. R. Gerhardt and A. Z. Weber, ECS Transactions, 92, 767 (2019).H. Vogt and R. J. Balzer, Electrochimica Acta, 50, 2073 (2005).

Self-Humidifying Proton Exchange Membranes for Fuel Cell Applications: Advances and Challenges

Polymer electrolyte fuel cells (PEFCs) provide efficient and carbon-free power by converting the hydrogen chemical energy. The PEFCs can reach their greatest performance in humidified condition, as proton exchange membranes (PEMs) should be humidified for their proton transportation function. Thus, external humidifiers are commonly employed to increase the water content of reactants. However, being burdened with external humidifiers can make the control of PEFCs complicated and costly, in particular for transportation application. To overcome this issue, self-humidifying PEMs have been introduced, with which PEFC can be fed by dry reactants. In fact, internal humidification is accomplished by produced water from the recombination of permeated hydrogen and oxygen gases on the incorporated platinum catalysts within the PEM. While the water production agent remains constant, there is a broad range of additives that are utilized to retain the generated water and facilitate the proton conduction path in the PEM. This review paper has classified the aforementioned additives in three categories: inorganic materials, proton-conductive materials, and carbon-based additives. Moreover, synthesis methods, preparation procedures, and characterization tests are overviewed. Eventually, self-humidifying PEMs endowed with platinum and different additives are compared from performance and stability perspectives, such as water uptake, proton conductivity, fuel cell performance, gas cross-over, and the overall durability. In addition, their challenges and possible solutions are reviewed. Considering the concerns regarding the long-term durability of such PEMs, it seems that further investigations can be beneficial to confirm their reliability for prolonged PEFC operation.

Evaluation of a variable flow ejector for anode gas circulation in a 50-kW class SOFC

Solid oxide fuel cells (SOFC) are highly efficient in terms of converting hydrogen's chemical energy into electrical energy through electrochemical reactions and for generating power in the range of several kW to several tens of kW. A variable flow ejector equipped with an adjustable recirculating flow rate mechanism was designed for this investigation. A prototype was manufactured to control the circulation of anode exhaust gas for a 50-kW class SOFC system. The ejector performance was evaluated using SOFC simulator equipment that simulated the pressure and temperature environment of a 50-kW SOFC system. In the heating simulation experiment, the mass flow rate ratio of the driving gas to the suction gas could be controlled from 3.7 to 5.4 under conditions simulating 100% of the rated load operation and from 4 to 7.5 when simulating 30%–50% of the partial load conditions. A simple heat transfer model for the motive nozzle was used in the ejector analysis, and issues for improving the ejector recirculation performance in the high-temperature field were identified.

Biochar-Assisted Water Electrolysis

This study has experimentally proven an approach to integrate electric energy and chemical energy of biomass into chemical energy of hydrogen by biochar-assisted water electrolysis (BAWE). This typ...

Feasible Energy System with Electrochemical Hydrogen Energy Storage for Leveling the Received Electricity at Large-Scale Solar Cell Installation

Introduction Recently, the large-scale installation of renewable energy is required to prevent global warming problem. Especially, the production cost of solar cell has drastically decreased recently. To install large-scale unstable power sources on renewable energy, the management of the gap between electricity demand and supply is a key issue. Thus, large-scale energy storage technologies have to progress to compensate the gap. As an energy storage, chemical energy of hydrogen is a promising candidate. Particularly in urban area, both “global hydrogen” and “local hydrogen” are required to supply sufficient energy to their huge energy demand. “Global hydrogen” is produced from low-cost primary energy globally and is transported for demand with a certain cost. “Local hydrogen” is produced by distributed energy system and is directly supplied without transportation. In the paper, we proposed a cost-competitive distributed energy system with the “local hydrogen” energy storage system. We analyzed the variation of total system cost by installing electrolysis cell (EC), fuel cell (FC) and secondary battery to compensate the gap due to electricity supply from large-scale solar cells (SC). We also proposed the appropriate SC arrangement for a middle size of distributed energy system. Method We evaluated the total system cost on the basis of real data from smart energy control system “Ene-Swallow”, developed by our research group, which manages the megawatt-scale distributed power sources in Tokyo Institute of Technology, Tokyo. The system has 1400 kW-SC, 100 kW-FC, 70 kW-gas engine and 100 kWh-lithium ion battery to manage the 10000 kW-scale electricity demand, which is suitable as a model for a middle-scale society with distributed power sources. The 650 kW-SC, which is almost half of total capacity of SC, is installed on the building (shown in Fig1) located in Tokyo. This building nearly achieves electricity self-sufficiency by the SC, 100 kW-FC and 70kW-gas engine. The building is covered with the “envelope of solar cells” (445 kW at the south wall, 40 kW at the west wall and 165 kW on the roof), where the maximum altitude in winter solstice is 31°. Global solar radiation in summer and winter are 15 MJ/m2 and 8 MJ/m2, respectively. Average temperature in summer and winter are 25°C and 5°C, respectively. In the location, the SCs on the building generates maximum electric power in winter because about 68% of SCs is installed at the south walls. The SC arrangement of the building has much smaller seasonal variation than typical arrangement on the roof to get better matching with the larger energy demands in winter. We constructed the energy system model to analyze the distributed energy system with electrochemical hydrogen energy storage and large-scale SC. In our model, the energy system with SC, alkaline EC, solid oxide FC, compressor, hydrogen tank and battery was assumed. Three hourly data from Apr/1/2016 to Mar/31/2017 were used (power generation from 750 kW-SC on the roofs, 650kW-SC on the building and electricity demand in the area). Based on these data, imaginary set of SC installation was assumed, where total amount of power generation from SC is equivalent to the electricity demand. Fig2 shows the energy flow in the model. In the daytime, the surplus electricity supplied from SC was assumed to be used for the production of hydrogen or battery charge. If the capacity of each device is not sufficient, the surplus electricity was assumed to be curtailed because it is hard to sell it in the future scenario with “large amount of solar energy”. In the night, the electricity to satisfy the demand was assumed to be generated by battery or FC. When the electricity supply is not enough, electricity was assumed to be purchased from an electrical grid. We carried out the energy balance simulation in the model by setting the capacities and technological parameters of devices. Finally, we analyzed the total system cost on the basis of the simulation. The analysis was carried out with the three cases of technology parameters of devices: (1) current (2015), (2) reduced SC price and (3) reduced all device prices (Table1). Result From the series of analysis, the total system cost can be reduced by installing the appropriate-scale hydrogen energy storage in the future. To achieve self-sufficiency ratio 100%, on the other hand, hydrogen tank cost drastically increased because its capacity got larger to absorb seasonal variation in power generation from SC. Controlling seasonal variation through SC arrangement can reduce the hydrogen tank cost. The cost-competitive system was proposed with the combination of hydrogen energy storage and SC arrangement. Figure 1

An Open-Source Toolbox for Multiphase Flow Simulation in a PEM Fuel Cell

A proton exchange membrane (PEM) fuel cell is an electrolytic cell that can convert chemical energy of hydrogen reacting with oxygen into electrical energy with no greenhouse gases generated in the process. To satisfy increasingly demanding application needs, providing fuel cells with better performance and higher efficiency are of paramount importance. Computational fluid dynamics (CFD) analysis is an ideal method for fuel cell design optimization. In this paper, a comprehensive CFD-based numerical tool that can accurately simulate multiphase flow and the major transport phenomena occurring in a PEM fuel cell is presented. The tool is developed using the Open Source Field Operation and Manipulation (OpenFOAM) software (a free open-source CFD code). This makes it flexible and suitable for use by fuel cell manufacturers and researchers to get an in-depth understanding of the cell working processes to optimize the design. The distributions of velocity, pressure, chemical species, Nernst potential, current density, and temperature at case study conditions are as expected. The polarization curve follows the same trend as those of the I-V curves from numerical model and experimental data taken from the literature. Furthermore, a parametric study showed thekey role played by the concentration constant in shaping the cell polarization curve. The developed toolbox is well-suited for research and development which is not always the case with commercial code. The work therefore contributes to achieving the objectives outlined in the International Energy Agency (IEA) Advanced Fuel Cell Annex 37 which promotes open-source code modelling of fuel cells. The source code can be accessed athttp://dx.doi.org/10.17632/c743sh73j8.1.

Combined heat and power (cogeneration) plant based on renewable energy sources and electrochemical hydrogen systems

The layout of a combined heat and power (cogeneration) plant based on renewable energy sources (RESs) and hydrogen electrochemical systems for the accumulation of energy via the direct and inverse conversion of the electrical energy from RESs into the chemical energy of hydrogen with the storage of the latter is described. Some efficient technical solutions on the use of electrochemical hydrogen systems in power engineering for the storage of energy with a cyclic energy conversion efficiency of more than 40% are proposed. It is shown that the storage of energy in the form of hydrogen is environmentally safe and considerably surpasses traditional accumulator batteries by its capacitance characteristics, being especially topical in the prolonged absence of energy supply from RESs, e.g., under the conditions of polar night and breathless weather. To provide the required heat consumption of an object during the peak period, it is proposed to burn some hydrogen in a boiler house.

Chemical Energy Sources Transformations by Remote Experiment

The paper describes the first experience with the set up, functioning and data evaluation of the remote experiment “Energy transformation” accessible via Internet (http://remotelab10.truni.sk) as a part of the e-laboratory at the Department of Physics, Faculty of Education, Trnava University in Trnava, Slovakia. The remote experiment control and data acquisition is based on the system ISES (Internet School Experimental System) and its control program and www page are built using the environment Easy Remote ISES. The main goal of the experiment is the elucidation of the energy transformations of three types of well known energy sources – photovoltaic cell (solar energy to electrical energy), electrolyser (electrical to chemical energy of hydrogen) and fuel cell (chemical energy of hydrogen to electrical energy) and finding optimal regimes for their maximum efficiencies. The perspective of the improvement of the experiment and its exploitation is given