have developed a new ammonia-based battery system to convert low-grade waste
heat into electricity. “The use of waste heat for power production would
allow additional electricity generation without any added consumption of fossil
fuels,” said Professor Bruce E Logan from the Pennsylvania State
University. “Thermally regenerative batteries are a carbon-neutral way to
store and convert waste heat into electricity with potentially lower cost than
solid-state devices,” said Logan.
waste heat is an artifact of many energy-generating methods. In automobiles,
waste heat generated in winter is diverted to run the vehicle heating system,
but in the summer. Using low-grade waste heat from an outside source, the
researchers distil ammonia from the effluent left in the battery anolyte and
then recharge it into the original cathode chamber of the battery.
chamber with the ammonia now becomes the anode chamber and copper is
re-deposited on the electrode in the other chamber, now the cathode, but
formerly the anode. The researchers switch ammonia back and forth between the
two chambers, maintaining the amount of copper on the electrodes.
we present a highly efficient, inexpensive and scalable ammonia-based thermally
regenerative battery where electrical current is produced from the formation of
copper ammonia complex,” the researchers said. Researchers note that the
ammonia liquid stream can convert the thermal energy to electrical energy in
needed, the battery can be discharged so that the stored chemical energy is
effectively converted to electrical power,” they said. The thermally
regenerative ammonia battery system can convert about 29 per cent of the
chemical energy in the battery to electricity and can be greatly improved with
future optimization The researchers
produced a power density of about 60 watts per square meter over multiple
cycles, which is six to 10 times higher than the power density produced by
other liquid-based thermal-electric energy conversion systems.
researchers note that the current thermally regenerative ammonia battery is not
optimised, so that tinkering with the battery could both produce more power and
reduce the cost of operating the batteries. The researchers were able to
increase power density by increasing the number of batteries, so that this
method is scalable to something that might be commercially attractive.
study was published in the journal Energy and Environmental Science.