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Titre
Pumped heat energy storage with liquid media: Thermodynamic assessment by a transcritical Rankine-like model
Autor(es)
Sujet
Energy storage
Water storage
Coupled transcritical Rankine model
Round trip efficiency
Internal and external irreversibilities
Heat leak
Clasificación UNESCO
2210.32 Termodinámica
Fecha de publicación
2022-12
Resumen
[EN]A pumped heat energy storage (PHES) system based on a Rankine cycle for supercritical working fluids, such
as carbon dioxide and ammonia, accounting for the irreversible latent and sensible heat transfers between
the working fluid and the storage liquid medium, as water or thermal oil, is analyzed. The model also
includes several parameters such as pressure losses, heat exchanger efficiencies, and isentropic efficiencies of
the compressor, pump, and expansion devices (such as turbines and valves), that take into account the main
internal and external losses and heat leak to the environment. The model allows for the calculation of specific
energy, the heat pump performance coefficient, heat engine efficiency, and overall round-trip efficiency, as well
as the temperatures of the working fluid and reservoirs. A zero-dimensional model is also used to determine
the time dependence of heat leak in the tanks. The main results show that this technology could achieve
round trip efficiency values in the order of 50–70%. Irreversibilities in compression and expansion appears
as the most influential energy losses factor. The time effect of the ambient conditions on the tanks has been
analyzed for a wet subtropical climate but it seems that the ambient conditions have no major influence on the
performance of the system. In addition, explicit numerical results and temperature–entropy plots are presented
for two representative systems as carbon dioxide-water and ammonia-thermal oil to take into account the main
values in an operating condition.
URI
ISSN
2352-152X
DOI
10.1016/j.est.2022.105966
Versión del editor
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- GIOETFE. Artículos [52]