Solar thermoelectric energy converters convert solar energy into thermal energy and then into electricity. These systems' primary advantage compared to photovoltaics are their ability to store energy as heat without the need for a battery. Solar thermoelectric energy converters can be used in many applications ranging from remote off-grid power generation to waste heat harvesting.
Solar-thermal power generations often requires mechanical engines that are large and expensive. Solar-thermoelectric converters use efficient thermoelectric materials and concentrators to improve efficiency, cost, temperature sensitivity, energy storage, and system size. Previously, this technology was limited by the thermoelectric figure-of-merit of materials (ZT, thought to be maximized around 1); however, new superlattice materials (e.g. the BixSb2-xTe3 system) and nanocomposites can achieve ZT greater than 3. This improved ZT allows thermoelectric convertors with higher efficiency.
There are two main components of a solar thermoelectric energy converter: the opto-thermal concentrator and the thermoelectric converter. The opto-thermal concentrator consists of a frequency selective surface coupled with a radiation capture structure that converts the solar energy to heat. This can be realized through a number of configurations including both reflective and refractive concentrators, depending on the application. The radiation capture structure is paired with one or more thermoelectric converters through conduction to create a solar thermoelectric converter with at least 4% efficiency.
- Improves energy conversion efficiency
- Improves energy storage for solar systems
- Improves temperature stability