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Title:
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Enthalpy-temperature plots to compare calorimetric measurements of phase change materials at different sample scales
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Author:
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Rathgeber, Christoph; Schmit, Henri; Miró, Laia; Cabeza, Luisa F.; Gutiérrez, Andrea; Ushak, Svetlana; Hiebler, Stefan
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Notes:
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Phase change materials (PCM) can provide high thermal energy storage capacities in narrow temperature ranges around their phase change temperature. The expectable maximum storage capacity of a PCM in a defined temperature range is equal to the enthalpy change in that range and can be determined via calorimetric measurements such as differential scanning calorimetry (DSC) or T-History calorimetry. T-History samples (aprox. 15 ml) are about 1000 times larger than DSC samples (aprox. 15 ml). Experiments in a pilot plant are performed to study the charging and discharging behaviour of even larger amounts of the PCM (aprox. 150 l). The common practise is to investigate PCM at one scale, rarely at two scales. In this work, the characterisation was carried out at three scales (DSC, T-History, and pilot plant) for four PCM (RT58, bischofite, D-mannitol, and hydroquinone). Thereby, the question arises how the enthalpy changes measured at different scales and under different conditions can be compared. In literature, the melting enthalpy is usually assigned to a single temperature without indicating the temperature range considered for evaluation. In very few instances, the enthalpy change within a defined temperature range is stated. In both cases, results measured under different conditions are difficult to compare. In this work, it is demonstrated that enthalpy-temperature plots facilitate the comparison and interpretation of measurements obtained under different experimental methods at different sample scales.
The work of ZAE Bayern was part of the project EnFoVerM and was supported by the German Federal Ministry for Economic Affairs and Energy under the project code 0327851D.
The work at the University of Lleida is partially funded by the Spanish government (ENE2011-22722, ENE2015-64117-C5-1-R (MINECO/FEDER) and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). GREA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). The authors want also to thank the collaboration of Antoni Gil from Massachusetts Institute of Technology (USA), Eduard Oró from Catalonia Institute for Energy Research (Spain), and Jaume Gasia and Gerard Peiró from University of Lleida (Spain). Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861).
The work of the University of Antofagasta was supported by FONDAP SERC-Chile (grant N° 15110019), and the Education Ministry of Chile Grant PMI ANT 1201. Authors thank the SALMAG Company for providing of bischofite. Andrea Gutierrez would like to acknowledge to the Ministry of Education of Chile her doctorate scholarship ANT 1106 and CONICYT/PAI N° 7813110010. |
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Subject(s):
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-Thermal energy storage (TES)
-Latent heat storage
-Phase change material (PCM)
-Storage capacity
-Enthalpy curve
-T-History |
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Rights:
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cc-by-nc-nd, (c) Elsevier, 2017
http://creativecommons.org/licenses/by-nc-nd/4.0/
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Document type:
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Article
acceptedVersion |
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Published by:
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Elsevier
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Share:
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