Non-dimensional design optimization of annular thermoelectric generators integrated in waste heat recovery applications

Abstract

The annular thermoelectric generators design facilitates the integration into conventional tubular heat exchangers which could enable their large-scale implementation in waste heat recovery applications for power generation. An analytical model is developed to identify the critical design parameters of annular thermoelectric generators (A-TEGs) integrated in heat exchangers. These parameters are found to be the diameter ratio, the P-to-N thickness ratio, and the fill ratio. The diameter and fill ratios are found to have a significant impact on the performance of the A-TEG system while the power output nearly plateaued at thickness ratios higher than 1.1. A novel dimensionless design factor (β) is proposed to guide the design optimization of the A-TEG system for maximized power generation. This design factor combines the diameter and fill ratios of the A-TEG design to define the locus over which the power output from the A-TEG system is always maximized. A detailed analytical model is developed and validated to simulate an A-TEG integrated heat exchanger for the purpose of optimizing the A-TEG design using the design factor (β). A parametric case study shows that at the optimum design factor, the material volume of the A-TEGs can potentially be reduced by 75% by decreasing the diameter and fill ratios with a reduction in the maximum power of only 11%. The study findings provide a useful tool to guide the efficient and cost-effective design of A-TEGs for waste heat recovery applications.