Analysis of the discharging process of latent heat thermal energy storage units by means of normalized power parametersShow others and affiliations
2023 (English)In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 72, article id 108428Article in journal (Refereed) Published
Abstract [en]
Many efforts are being made to mitigate the main disadvantage of most phase change materials - their low thermal conductivities - in order to deliver latent heat energy storage systems (LHESS) with adequate perfor-mance. However, the effect of applied methods is difficult to compare as they are mostly tested for different storage types and sizes and/or different boundary and initial conditions, which hinders rapid progress in the optimization of these approaches. In this work, a previously developed method for comparing the performance of LHESS is applied to experimental results of different storage systems under different conditions and subsequently analyzed and further refined. The main idea of the method is to normalize the power with the volume and a reference temperature difference and compare its mean value plotted over the normalized mean capacity flow of the heat transfer fluid (HTF). This enables the presentation of the results in a compact and easily comparative way. Attention has to be paid when it comes to the choice of the reference temperature difference, the reference volume and the method for calculating the mean value. Two variants of calculating the mean value (time-weighted and energy-weighted) and two variants of reference temperatures for determining the temperature difference to the inlet temperature of the HTF (initial temperature and melting temperature) are applied and discussed in detail. While the method significantly increases the comparability of results, none of the options listed above are without drawbacks. Approaches are shown to reduce or eliminate these drawbacks in the future. The recommendation for comparing different LHESS under different conditions is to use the method described here and clearly state the chosen reference temperature, reference volume and method for calculating the mean value.
Place, publisher, year, edition, pages
Elsevier BV , 2023. Vol. 72, article id 108428
Keywords [en]
Power, Evaluation, Performance indicators, Phase change materials, Latent heat, Thermal energy storage
National Category
Energy Engineering
Identifiers
URN: urn:nbn:se:kth:diva-336047DOI: 10.1016/j.est.2023.108428ISI: 001052330400001Scopus ID: 2-s2.0-85169818869OAI: oai:DiVA.org:kth-336047DiVA, id: diva2:1796007
Note
QC 20230911
2023-09-112023-09-112023-09-11Bibliographically approved