Performance Testing of Salt-Gas Heat Exchangers for Pumped Thermal Energy Storage
4 affiliations
- 1Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
- 2Alfa Laval (Sweden)
- 3Malta Iberia Pumped Heat Electricity Storage S.L.U.
- 4Malta Hochtemperatur Wärmepumpen Stromspeicher GmbH
Abstract
Pumped Thermal Energy Storage (PTES) systems store energy by driving a temperature difference between hot and cold reservoirs, offering higher exergy efficiency than conventional thermal storage power cycles. For example, Malta Inc. has developed a PTES system based on steam and molten salt for utility-scale energy storage. In addition to grid applications, this technology could also improve the efficiency of hybrid PV/CSP power plants. This paper presents an experimental investigation of a key PTES component: the salt-gas heat exchanger. Two compact, high-efficiency heat exchanger prototypes, provided by Alfa Laval, were tested at DLR’s molten salt test facility TESIS:com (Test Facility for Thermal Energy Storage in Molten Salt: Components), using air and Solar Salt as heat transfer fluids. The study focuses on evaluating pressure drop and drainability under the demanding operating conditions imposed by high-temperature, corrosive molten salt, requiring complex instrumentation. Pressure drops were assessed by validating multiple sensor types through cross-comparison. Results showed the expected increase in pressure drop with increasing mass flow rate, with no significant variation between 300 °C and 390 °C. Both gravity-driven and compressed-air-assisted drainage were investigated. Compressed air accelerated drainage but did not significantly affect the drained salt mass or residual salt content inside the heat exchanger. Residual salt was qualitatively assessed using post-drainage airflow pressure drop measurements. The developed methods contribute to the standardization and advancement of molten salt component testing.
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BibTeX
@article{prenzel2026performance,
title = {{Performance Testing of Salt-Gas Heat Exchangers for Pumped Thermal Energy Storage}},
author = {Marco Prenzel and Freerk Klasing and Per Wanersjo and Maria Navasa and Jaime González and Janina Hippler-Nettlau and Michael Geyer and Thomas Bauer},
journal = {SolarPACES Conference Proceedings},
year = {2026},
month = oct,
doi = {10.52825/solarpaces.v4i.2985},
url = {https://doi.org/10.52825/solarpaces.v4i.2985},
note = {CC BY},
}
RIS
TY - JOUR
TI - Performance Testing of Salt-Gas Heat Exchangers for Pumped Thermal Energy Storage
AU - Marco Prenzel
AU - Freerk Klasing
AU - Per Wanersjo
AU - Maria Navasa
AU - Jaime González
AU - Janina Hippler-Nettlau
AU - Michael Geyer
AU - Thomas Bauer
PY - 2026
DA - 2026/10/24
JO - SolarPACES Conference Proceedings
DO - 10.52825/solarpaces.v4i.2985
UR - https://doi.org/10.52825/solarpaces.v4i.2985
AB - Pumped Thermal Energy Storage (PTES) systems store energy by driving a temperature difference between hot and cold reservoirs, offering higher exergy efficiency than conventional thermal storage power cycles. For example, Malta Inc. has developed a PTES system based on steam and molten salt for utility-scale energy storage. In addition to grid applications, this technology could also improve the efficiency of hybrid PV/CSP power plants. This paper presents an experimental investigation of a key PTES component: the salt-gas heat exchanger. Two compact, high-efficiency heat exchanger prototypes, provided by Alfa Laval, were tested at DLR’s molten salt test facility TESIS:com (Test Facility for Thermal Energy Storage in Molten Salt: Components), using air and Solar Salt as heat transfer fluids. The study focuses on evaluating pressure drop and drainability under the demanding operating conditions imposed by high-temperature, corrosive molten salt, requiring complex instrumentation. Pressure drops were assessed by validating multiple sensor types through cross-comparison. Results showed the expected increase in pressure drop with increasing mass flow rate, with no significant variation between 300 °C and 390 °C. Both gravity-driven and compressed-air-assisted drainage were investigated. Compressed air accelerated drainage but did not significantly affect the drained salt mass or residual salt content inside the heat exchanger. Residual salt was qualitatively assessed using post-drainage airflow pressure drop measurements. The developed methods contribute to the standardization and advancement of molten salt component testing.
SN - 2751-9899
ER -