Enhancing Low-Grade Thermal Energy Recovery in a Thermally Regenerative Ammonia Battery Using Elevated Temperatures

Fang Zhang, Nicole LaBarge, Wulin Yang, Jia Liu, Bruce E. Logan

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


© 2015 WILEY-VCH Verlag GmbH & Co. KGaA. A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72°C produced a power density of 236±8 Wm-2, with a linear decrease in power to 95±5 Wm-2 at 23°C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Whm-3 at a discharge energy efficiency of 54% and a temperature of 37°C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.
Original languageEnglish (US)
Pages (from-to)1043-1048
Number of pages6
Issue number6
StatePublished - Feb 13 2015
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-I1-003-13
Acknowledgements: The authors thank David Jones for help with the analytical measurements. We also thank Dr. Marta Hatzell for useful discussions. This research was supported by Award KUS-I1-003-13 from the King Abdullah University of Science and Technology (KAUST).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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