A 1 KW Thermoelectric Generator for Low-temperature Geothermal Resources

Most of the current thermal power-generation technologies must first convert thermal energy to mechanical work before producing electricity. Thermoelectric generation technology, as one entirely solid-state energy conversion method, can directly transform thermal energy into electricity by using thermoelectric transformation materials. A thermoelectric power converter has no moving parts, and is compact, quiet, highly reliable and environmentally friendly. Therefore, the whole system can be simplified and operated over an extended period of time with minimal maintenance. In addition, it has a wider choice of thermal sources. It can utilize both the highand low-quality heat to generate electricity. The low-quality heat may not be utilized effectively by conventional methods such as ORC technology. In this study, a direct heat to electricity (DHE) technology using the thermoelectric effect, without the need to change through mechanical energy, was applied to harvest low-enthalpy thermal work. Such a power generation system has been designed and built using thermoelectric generator (TEG) modules manufactured using a new technique. The targets of this technique were low cost and high thermal to electricity efficiency. Experiments have been conducted to measure the output power at different conditions: different inlet temperature and temperature differences between hot and cold sides. TEG modules manufactured with different materials have also been tested. The power generator assembled with TEG modules had an installed power of 1 KW at a temperature difference of around 120 °C. The power generated by the thermoelectric system is almost directly proportional to the temperature difference between the hot and the cold sides. The cost of the DHE power generator is much lower than that of photovoltaics (PV) in terms of equivalent energy generated. The TEG systems are ready to be applied practically in many geothermal sites with low temperature resources, including oil fields where fossil and geothermal energies are co-produced.