Direct Thermoelectric Power Generation
Thermoelectric power generation utilizes a temperature gradient and heat flow in order to produce useful power output. Direct thermoelectric power generation (direct generation) means creating a heat flow and temperature difference with the primary intent of producing power by TE conversion. In most cases, the heat comes from combustion of a hydrocarbon fuel (butane, propane, diesel, JP-8) or from the decay of a radioactive isotope.
For direct generation applications, efficiency is paramount – not only the TEG efficiency, but also the overall system efficiency. Combustion efficiency, recuperation of the exhaust gases, system heat losses, fan power consumption, pump power and electronics/power conditioning losses all impact system efficiency. As for the TEG, high efficiency follows from maximizing the temperature difference across the TEG and the average device ZT over that temperature difference.
Due to the extremely high-energy content of hydrocarbon fuels, even a modest TEG efficiency can yield an energy density several times greater than Lithium-ion batteries, provided the design properly manages the combustion process and balance-of-plant power consumption. This advantage opens the door for many long-life, smaller power sources for a variety of applications, including soldier electronics power.