Thermoelectric Device

Providing safe energy in developing countries

One of the most pressing issues in developing countries today is the limited access to the electricity grid. This situation is aggravated by indoor pollution from inefficient cookstoves, gravely affecting people’s health. TED aims to alleviate these problems by providing an affordable approach to generate electricity from waste heat produced by efficient cookstoves using thermoelectric generators. The aim of the project was to use the heat waste generated by cooking stoves to produce 20W of electricity whilst protecting the generators from damage due to overheating.

An extensive challenge

The development of the device was achieved through analytical calculations, numerical models as well as empirical data obtained from various experiment. The device was tested in conditions mimicking those in which it is to be used.

Fail-safe design

Thermoelectric generators are sensitive devices which operate in specific temperature ranges. Being exposed to heat from exhaust gases of solid fuel combustion ranging from 100°C to 400°C, the generators were kept cool using fans powered directly from the electricity produced. A functional fail-safe overheating prevention mechanism was developed to keep the generators below their upper temperatures limits and effectively safeguarding the internal components of the TED.

Mixed outcomes (or learning from shortcomings)

The electric circuits aimed at powering the fans and the actuator, as well as charging an external car battery operated and showed conclusive results. The power output, however, was significantly lower than initially predicted. This is due to several main factors, namely the thermal buckling of the bottom plate and the degradation of the thermoelectric generators.

These causes were well documented and potential improvements to the design were put forward for further development. It was concluded that the use of TEGs for domestic power generation has potential and should be explored in further depth.

Third year project in collaboration with Leonardo Paoli, Alex Podgurschi and Nils Rönner.
2012-2013 | Imperial College London