EconPapers    
Economics at your fingertips  
 

Thermal cycle performance of thermocline storage: numerical and experimental exergy analysis

S. Vannerem, P. Neveu and Q. Falcoz

Energy, 2023, vol. 278, issue C

Abstract: The performance of a dual-media thermocline storage is studied in stationary periodic operation. Successive cycles are carried out until a stabilised behaviour is obtained. Numerical results are compared to experiments realised on a 107 kWh prototype combining thermal oil and alumina. Two performance indicators are studied: utilisation rate and exergy efficiency. The utilisation rate decreases as the thermocline thickens over the cycles, while the exergy efficiency increases over the cycles, mainly due to lower heat losses improving the energy efficiency. Experimental values stabilise around UR = 53% and ηex= 73% at the fifth cycle. A new indicator is introduced: the storage quality factor Ψs, which quantifies the exergy losses due to the process. Experiments and simulations show good agreement, with a slight underestimation of heat losses by the model. Exergetic performance of thermocline storage is thus validated experimentally on a prototype-scale setup in stationary periodic regime, with satisfying value: Ψs≈ 0.99. The influence of stop thresholds on performance is then examined numerically. The utilisation rate decreases with strict thresholds (κch=κd= 0.05) because it prevents the storage to be fully loaded and because the thermocline thickens over the cycles if not extracted from the tank. The exergy efficiency globally increases for hybrid threshold (strict during charge, soft during discharge), with a maximum of ηex= 96.5% for κch= 0.05, κd= 0.95. In that configuration, the time during which the storage is hot is minimised, decreasing heat losses. Besides, setting strict thresholds limits the variation of the outlet temperature and reduces exergy destruction.

Keywords: Sensible heat storage; Thermocline; Packed bed; Cyclic behaviour; Exergy analysis; Experimental (search for similar items in EconPapers)
Date: 2023
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544223010411
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:278:y:2023:i:c:s0360544223010411

DOI: 10.1016/j.energy.2023.127647

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu (repec@elsevier.com).

 
Page updated 2024-12-28
Handle: RePEc:eee:energy:v:278:y:2023:i:c:s0360544223010411