Heat Recovery Enhancement Using Thermoelectric Generators

This is a PhD thesis.

A lot of energy is wasted in the form of heat with exhaust gases from the chimneys of industrial facilities. Using thermoelectric generators (TEGs) is a promising solution to recover a percentage of this wasted energy. They are small and compact with no maintenance required. The main challenge is to provide a proper cooling for them for efficient operation and energy conversion.

In this study, a 3D model is presented to simulate the performance of thermoelectric generators when cooled passively by natural convection. It enables prediction of the complete temperature and voltage distribution through them. The model is acceptably accurate and requires reasonable computational power.

This model is used to study the impact of varying the vertical pitch distance between the modules of the TEGs when mounted on a vertical chimney. Also, the impact of the chimney’s tilt angle caused by its convergent section. After that, the impact of using heat spreaders on the cold side of the chimney is studied. Finally, a new design of conventional heat sinks is proposed to improve the performance of the upper modules of the TEG.

An experimental test rig is built to compare the performance of the liquid-cooling system with the heat pipes’ system. An important conclusion is reached that the water block performance is critical and the liquid cooling system could achieve higher net output power compared to the heat pipes’ system.