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Exploitation of thermochemical cycles based on solid oxide redox systems for thermochemical storage of solar heat. Part 1: Testing of cobalt oxide-based powders

Agrafiotis, Christos und Roeb, Martin und Schmücker, Martin und Sattler, Christian (2014) Exploitation of thermochemical cycles based on solid oxide redox systems for thermochemical storage of solar heat. Part 1: Testing of cobalt oxide-based powders. Solar Energy, 102, Seiten 189-211. Elsevier. ISSN 0038-092X.

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Offizielle URL: http://dx.doi.org/10.1016/j.solener.2013.12.032

Kurzfassung

Thermochemical storage of solar heat exploits the enthalpy effects of reversible chemical reactions for the storage of solar energy. Among the possible reversible gas–solid chemical reactions, utilization of a pair of reduction–oxidation (redox) reactions of solid oxides of multivalent metals can be directly coupled to Concentrated Solar Power (CSP) plants employing air as the heat transfer fluid avoiding thus the need for separate heat exchangers. The redox pair of cobalt oxides Co3O4/CoO in particular, is characterized by high reaction enthalpies and thus potential heat storage capacity. Parametric testing of cobalt oxide-based powder compositions via Thermo-Gravimetric Analysis/Differential Scanning Calorimetry was performed to determine the temperature range for cyclic reduction–oxidation and optimize the process parameters for Maximum reduction and re-oxidation extent. The heating/cooling rate is an important means to control the extent of the oxidation reaction which is slower than reduction. Complete re-oxidation was achieved within reasonable times by performing the two reactions at close temperatures and by controlling the heating/cooling rate. Under proper operating conditions Co3O4 powders exhibited longterm (30 cycles), complete and reproducible cyclic reduction/oxidation performance within the temperature range 800–1000 �C. No benefits occurred by using Ni, Mg and Cu cobaltates instead of “pure” Co3O4. The Co3O4 raw material’s specific surface area is an influential factor on redox performance to which observed differences among powders from various sources could be attributed. Presence of Na was also shown to affect significantly the evolution of the products’ microstructure, though not necessarily combined with improved redox performance.

Dokumentart:Zeitschriftenbeitrag
Titel:Exploitation of thermochemical cycles based on solid oxide redox systems for thermochemical storage of solar heat. Part 1: Testing of cobalt oxide-based powders
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Agrafiotis, Christoschristos.agrafiotis@dlr.de
Roeb, MartinMartin.roeb@dlr.de
Schmücker, MartinMartin.Schmuecker@dlr.de
Sattler, Christianchristian.sattler@dlr.de
Datum:11 Februar 2014
Erschienen in:Solar Energy
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:102
Seitenbereich:Seiten 189-211
Herausgeber:
HerausgeberInstitution und/oder E-Mail-Adresse der Herausgeber
Epstein, MichaelNICHT SPEZIFIZIERT
Verlag:Elsevier
ISSN:0038-092X
Status:veröffentlicht
Stichwörter:Solar energy; Thermochemical cycles; Thermochemical heat storage; Redox reactions; Cobalt oxide; Cobaltates
HGF - Forschungsbereich:Energie
HGF - Programm:Erneuerbare Energie
HGF - Programmthema:Konzentrierende Solarsysteme
DLR - Schwerpunkt:Energie
DLR - Forschungsgebiet:E SF - Solarforschung
DLR - Teilgebiet (Projekt, Vorhaben):E - Solare Verfahrenstechnik (alt)
Standort: Köln-Porz
Institute & Einrichtungen:Institut für Solarforschung > Solare Verfahrenstechnik
Institut für Werkstoff-Forschung > Keramische Strukturwerkstoffe
Hinterlegt von: Dr.rer.nat. Christian Sattler
Hinterlegt am:24 Feb 2014 07:38
Letzte Änderung:22 Sep 2014 11:13

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