Premium
Enhancing Low‐Grade Thermal Energy Recovery in a Thermally Regenerative Ammonia Battery Using Elevated Temperatures
Author(s) -
Zhang Fang,
LaBarge Nicole,
Yang Wulin,
Liu Jia,
Logan Bruce E.
Publication year - 2015
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201403290
Subject(s) - electrolyte , anode , power density , ammonia , battery (electricity) , thermal energy , chemistry , energy recovery , materials science , electrode , chemical engineering , thermodynamics , energy (signal processing) , power (physics) , organic chemistry , physics , statistics , mathematics , engineering
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 W m −2 , with a linear decrease in power to 95±5 W m −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 Wh m −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.