Y-Shaped Design of Colaminar Flow Thermo-Electrochemical Cells through Mathematical Modeling

Thermo-electrochemical cells (TECs) have emerged as a promising avenue for waste heat recovery. However, it is challenging to achieve a rapid ion transport while maintaining a high temperature difference between the anode and cathode. In this work, a Y-shaped colaminar flow TEC is first proposed to solve the contradiction between ion transport improvement and temperature difference establishment. The design of TEC is optimized based on the mathematical model. The effect of geometry (flow channel and angle between sun-channels) and operating conditions (flow rate and heat dissipation) on the TEC performance is comprehensively evaluated. The results demonstrate that the colaminar flow of hot- and cold-electrolytes can establish the temperature gradient between the anode and cathode with a facilitated convection transport of ions. The TEC with the divergent channel can achieve a 55% improvement in the power output at a velocity of 0.01 m/s. In addition, the optimal length of the main channel and angle between subchannels are closely related to the electrolyte flow velocity; a shorter channel length or larger angle is required to ensure a stable power output at a low electrolyte inlet velocity. In conclusion, the Y-shaped colaminar flow TECs can achieve a sufficient mass transport of chemical species and a good establishment of temperature difference, providing an alternative design for TEC application and also an effective method to mitigate the underlying challenges between heat and mass transport during thermo-electrochemical conversion in the TECs.