Effect of phase separation and supercooling on the storage capacity in a commercial latent heat thermal energy storage: Experimental cycling of a salt hydrate PCM
Artikel i vetenskaplig tidskrift, 2020

Latent heat storage technologies offer process benefits like daily peak shaving. In this work a commercial storage design for storing cold thermal energy has been studied using a laboratory prototype containing 168 kg of a commercial salt-hydrate phase change material (PCM). The storage was charged and discharged with subsequent cycles at different mass flow rates over a fixed temperature range and duration. It was found that the PCM TES design exhibits phase separation and increased supercooling with continuous cycling. Both phenomena lead to a gradual decrease of the effective storage capacity. With later cycles only the bottom part stores latent heat, while the top and middle parts of the storage remain liquid. The results were repeatable and are consistent with T-History measurements of samples from the PCM TES before and after cycling. It is likely that the PCM itself does not suffer from incongruent melting. Instead, the phase separation is likely to occur due to a segregation of different liquid phases across the height of the storage. It was found that T-History measurements alone are not able to predict this behavior. Moreover, it is shown that phase separation in the storage can be reversed by increasing the PCM temperature and mechanical mixing of the liquid phase. This phase separation has to be prevented in future work in order to achieve stable performance with the studied storage design.

Supercooling

Phase Change Material

T-History

Salt-Hydrate

Thermal Energy Stoage

Phase Separation

Författare

Pepe Tan

Chalmers, Arkitektur och samhällsbyggnadsteknik, Byggnadsteknologi

Patrik Lindberg

ÅF Pöyry AB

Kaia Eichler

ÅF Pöyry AB

Per Löveryd

Akademiska Hus AB

Pär Johansson

Chalmers, Arkitektur och samhällsbyggnadsteknik, Byggnadsteknologi

Angela Sasic Kalagasidis

Chalmers, Arkitektur och samhällsbyggnadsteknik, Byggnadsteknologi

Journal of Energy Storage

2352-152X (eISSN)

Vol. 29 101266

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Energimyndigheten, 2015-01-01 -- 2017-12-31.

Demonstrationsanläggning för lagring av kyla i fasändringsmaterial

Naturvårdsverket, 2017-01-01 -- 2018-06-30.

Design och driftsanvisningar för värmelager med fasändringsmaterial. Demonstrationsanläggning kyllager i kontorsbyggnad

Energimyndigheten, 2019-03-15 -- 2020-12-31.

Styrkeområden

Energi

Ämneskategorier

Annan materialteknik

Energisystem

Husbyggnad

DOI

10.1016/j.est.2020.101266

Mer information

Senast uppdaterat

2020-09-17