Experimental evaluation of a pilot-scale thermochemical storage system for a concentrated solar power plant

S. Tescari*, A. Singh, C. Agrafiotis, L. de Oliveira, S. Breuer, B. Schlögl-Knothe, M. Roeb, C. Sattler

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

52 Citations (Scopus)

Abstract

A first of its kind pilot-scale redox-based thermochemical storage system has been set up and operated under near-realistic conditions inside a solar power tower plant. The storage unit is made of inert honeycomb supports (cordierite) coated with 88 kg of redox active material (cobalt oxide). An experimental campaign has been carried out consisting of 22 thermochemical charge-discharge cycles. The heat absorbed or released by the chemical reaction became clearly evident through the temperature evolution inside the reactive material. It allows to store or release energy at constant temperature when crossing respectively the reduction/oxidation temperature of the Co3O4/CoO pair. A storage performance factor (PF) was defined to evaluate how each experiment approaches the ideal behavior. During the complete campaign no measurable cycle-to-cycle degradation was observed and the system average capacity was very close to the ideal case of PF= 0.84. The advantage of thermochemical storage could be quantified by comparing the storage capacity, to that of a sensible-only storage unit made of uncoated cordierite honeycombs. The thermochemical system offered almost double storage capacity (47.0 kW h) cf. the same volume of the sensible-only case (25.3 kW h).

Original languageEnglish
Pages (from-to)66-75
Number of pages10
JournalApplied energy
Volume189
DOIs
Publication statusPublished - 1 Mar 2017
Externally publishedYes

Keywords

  • Cobalt oxide
  • Concentrated solar energy
  • Energy storage
  • Pilot-scale system
  • Redox cycles
  • Thermochemical storage

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