Investigation of a Thermocapacitive Cycle by Aqueous Supercapacitors for Multifunctional Heat Pump and Energy Storage: Article No. 121465

Thermocapacitive cycles are promising thermal and energy storage cycles using supercapacitors, which can achieve thermal efficiencies over 50% of the Carnot limit. There is a lack of work investigating the use of thermocapacitive effects in practical heat pumps. This paper explores the design of thermocapacitive cells with higher temperature changes to be better suited for heat pumping applications. To evaluate the cell designs on temperature changes, pouch type cells are prototyped and modeled, and tested using a micro-calorimeter. A peak adiabatic temperature span of a LiCl aqueous cell is 2.7 degrees C. By arranging the cells in a cascade manner, the projected adiabatic temperature span can reach up to 12 degrees C with a heating density of 15 kW m-3 and an energy storage density of 0.83 kWh m-3. Models predict that this could be increased to 30 degrees C and 1.65 kWh m-3 through improvements to cell capacitance and thermopower. Incorporating the energy storage capabilities into heating and cooling devices can be beneficial to building thermal management as energy storage becomes increasingly important for energy system integration.