Thermoelectric generators (TEG) can harvest solar energy during the day using solar flat panels. They can also benefit from the use of a material that stores solar energy to generate additional power at night, when the panel cools down and the energy stored in this material travels back, through the TEG. The soil can be used as the material that stores solar energy, but the performance of such systems, with the heat sink buried in the soil, depends on the ambient and the soil temperature, parameters which can change drastically with the latitude of the location where the TEG is installed. We present an experimental study with the comparison of the potential energy that can be collected from a TEG system with heat sink buried at different depths and at different latitudes: Campinas, Brazil − 22 ∘ 54 ′ 20 ′ ′ S; and Mataró, Catalonia, Spain − 41 ∘ 32 ′ 17 ′ ′ N. The potential of energy harvesting calculated during 32 winter days in Campinas is 72% of the total calculated during 205 days in Mataró. Experimental results obtained from a complete TEG system showed that in Campinas, during one day, it was possible to store 34.11 J of electrical energy in a supercapacitor. Notably, we demonstrate that the energy generated during the night by the heat stored into the soil can be as high as the energy generated during the day.
Experimental study of cascaded thermoelectric generators with differences in focal length using LED lights energy radiation
