The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Antje Worner - One of the best experts on this subject based on the ideXlab platform.
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thermochemical energy storage in kw scale based on cao ca oh 2
Energy Procedia, 2014Co-Authors: Marc Linder, Christian Roskopf, Matthias Schmidt, Antje WornerAbstract:In order to investigate thermochemical energy storage in larger scale, a test bench as well as a reactor containing around 20 kg of Reaction material has been built and brought into operation. This investigation is based on the reversible decomposition Reaction of calcium hydroxide, due to its wide availability, high Reaction Enthalpy and promising temperature range for CSP plants. Additionally, a developed simulation tool was used to analyze the experimental results. The comparison of the discharging processes showed a good agreement but also revealed thermal losses due to the experimental setup and the operation mode of the thermochemical storage. Therefore, first operation strategies of thermal energy storages based on chemical Reactions can be derived.
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a thermodynamic and kinetic study of the de and rehydration of ca oh 2 at high h2o partial pressures for thermo chemical heat storage
Thermochimica Acta, 2012Co-Authors: Franziska Schaube, Lisa Koch, Antje Worner, Hans MullersteinhagenAbstract:Abstract Heat storage technologies are used to improve energy efficiency of power plants and recovery of process heat. Storing thermal energy by reversible thermo-chemical Reactions offers a promising option for high storage capacities especially at high temperatures. Due to its low material cost, the use of the reversible Reaction Ca(OH) 2 ⇌ CaO + H 2 O has been proposed. This paper reports on the physical properties such as heat capacity, thermodynamic equilibrium, Reaction Enthalpy and kinetics. To achieve high Reaction temperatures, high H 2 O partial pressures are required. Therefore the cycling stability is confirmed for H 2 O partial pressures up to 95.6 kPa and the dehydration and hydration kinetics are studied. Quantitative data are collected and expressions are derived which are in good agreement with the presented measurements. At 1 bar H 2 O partial pressure the expected equilibrium temperature is 505 °C and the Reaction Enthalpy is 104.4 kJ/mol.
M Zhu - One of the best experts on this subject based on the ideXlab platform.
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enhanced reversible hydrogen storage properties of a mg in y ternary solid solution
International Journal of Hydrogen Energy, 2013Co-Authors: F P Luo, H Wang, L Z Ouyang, Meiqin Zeng, J W Liu, M ZhuAbstract:Abstract A Mg(In, Y) ternary solid solution was successfully synthesized by two-step method, namely sintering the elemental powders and subsequent milling. The formation of Mg(In, Y) indicates that the solubility of Y in the Mg lattice is expanded due to the existence of In. The as-synthesized Mg90In5Y5 solid solution transformed to MgH2, YH3, In3Y and MgIn compound upon hydrogenation, the hydrogenated products except for the YH3 recovered to Mg(In, Y) solid solution after dehydrogenation. The Mg90In5Y5 solid solution exhibited a decreased Reaction Enthalpy of 62.9 kJ/(mol H2), reduction by ca. 5 kJ/(mol H2) or 12 kJ/(mol H2) than the Mg95In5 binary solid solution and pure Mg, respectively. The working temperature as well as the activation energies for the hydriding and dehydriding were also decreased in comparison with those of Mg(In) binary solid solution, which are attributed to the reduced Reaction Enthalpy and the catalytic role of YH3. Our work indicates that the thermodynamic and kinetic tuning of MgH2 are realized in the Mg(In, Y) ternary solid solution.
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altered desorption Enthalpy of mgh2 by the reversible formation of mg in solid solution
Scripta Materialia, 2011Co-Authors: Huichi Zhong, H Wang, Jian Liu, Dalin Sun, M ZhuAbstract:Mg(In) solid solution, which was prepared by mechanical alloying, can be reversibly formed by dehydriding from its hydrogenated products (MgH2, MgIn and Mg2In). In situ X-ray diffraction analysis for the dehydriding process revealed that the Mg2In and ordered MgIn compounds transformed to the disordered MgIn compound (β phase), which then reacted with the MgH2 to form the Mg(In) solid solution, and vice versa. The Mg(In) solid solution shows decreased Reaction Enthalpy compared with pure Mg.
Andrea Ambrosini - One of the best experts on this subject based on the ideXlab platform.
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doped calcium manganites for advanced high temperature thermochemical energy storage
International Journal of Energy Research, 2016Co-Authors: Sean M Babiniec, Eric N Coker, James E Miller, Andrea AmbrosiniAbstract:Developing efficient thermal storage for concentrating solar power plants is essential to reducing the cost of generated electricity, extending or shifting the hours of operation, and facilitating renewable penetration into the grid. Perovskite materials of the CaBxMn1-xO3-δ family, where B = Al or Ti, promise improvements in cost and energy storage density over other perovskites currently under investigation. Thermogravimetric analysis of the thermal reduction and reoxidation of these materials was used to extract equilibrium thermodynamic parameters. Lastly, the results demonstrate that these novel thermochemical energy storage media display the highest Reaction Enthalpy capacity for perovskites reported to date, with a Reaction Enthalpy of 390 kJ/kg, a 56% increase over previously reported compositions.
Hui Wang - One of the best experts on this subject based on the ideXlab platform.
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Fully Reversible De/hydriding of Mg Base Solid Solutions with Reduced Reaction Enthalpy and Enhanced Kinetics
The Journal of Physical Chemistry C, 2014Co-Authors: Hui Wang, Liuzhang Ouyang, Dalin Sun, Haichang Zhong, Jiangwen Liu, Qingan Zhang, Min ZhuAbstract:This paper presents a new approach to tune the de/hydriding thermodynamic properties of Mg via forming reversible Mg base solid solutions in the Mg–In and Mg–In–Al systems by mechanical milling. The effect of solubility of In and Al on the reversible formation of solid solution structure and hydrogen storage properties were investigated. It is found that although the solute atoms unavoidably are rejected upon hydriding, the hydrogenated products of MgH2 and intermediate MgIn compound could fully transform back to solid solution after dehydrogenation. In the hydriding of Mg(In, Al) ternary solid solution, Al would get dissolved into MgIn compound rather than forming free Al like the Mg(Al) binary solid solution. Therefore, the presence of In improves the dehydriding reversibility of Mg(Al) solid solution, and the reversible Al concentration could be increased up to the 8 at. %, which is just the solubility limit of Al in Mg by mechanical milling. The reversible phase transformation is responsible for the r...
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thermodynamic tuning of mg based hydrogen storage alloys a review
Materials, 2013Co-Authors: Min Zhu, Liuzhang Ouyang, Hui WangAbstract:Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH2 are alloying, nanostructuring, and changing the Reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored Reaction Enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys.
Min Zhu - One of the best experts on this subject based on the ideXlab platform.
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Fully Reversible De/hydriding of Mg Base Solid Solutions with Reduced Reaction Enthalpy and Enhanced Kinetics
The Journal of Physical Chemistry C, 2014Co-Authors: Hui Wang, Liuzhang Ouyang, Dalin Sun, Haichang Zhong, Jiangwen Liu, Qingan Zhang, Min ZhuAbstract:This paper presents a new approach to tune the de/hydriding thermodynamic properties of Mg via forming reversible Mg base solid solutions in the Mg–In and Mg–In–Al systems by mechanical milling. The effect of solubility of In and Al on the reversible formation of solid solution structure and hydrogen storage properties were investigated. It is found that although the solute atoms unavoidably are rejected upon hydriding, the hydrogenated products of MgH2 and intermediate MgIn compound could fully transform back to solid solution after dehydrogenation. In the hydriding of Mg(In, Al) ternary solid solution, Al would get dissolved into MgIn compound rather than forming free Al like the Mg(Al) binary solid solution. Therefore, the presence of In improves the dehydriding reversibility of Mg(Al) solid solution, and the reversible Al concentration could be increased up to the 8 at. %, which is just the solubility limit of Al in Mg by mechanical milling. The reversible phase transformation is responsible for the r...
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thermodynamic tuning of mg based hydrogen storage alloys a review
Materials, 2013Co-Authors: Min Zhu, Liuzhang Ouyang, Hui WangAbstract:Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH2 are alloying, nanostructuring, and changing the Reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored Reaction Enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys.
