Thermoelectrics are materials that can generate electricity from the application of a temperature gradient, or vice versa, through the thermoelectric effect. By exploiting this coupling between thermal and electrical properties, thermoelectric devices can be made that carry heat from a cold to a hot side (refrigeration) or that generate electricity from heat flows.
Thermoelectric devices, such as Vulcan Force, are made from thermoelectric modules. A thermoelectric module is an array of thermocouples connected electrically in series but thermally in parallel. Many couples are used (in both power generation and cooling) becuause the voltage drop across one couple is only on the order of millivolts. Connecting many in series brings the voltage closer to that found in typical DC power souces.
If the hot ends of the n-type and p-type material are electrically connected, and a load connected across the cold ends, the voltage produced by the Seebeck effect will cause current to flow through the load, generating electrical power. The electrical power produced is the product of the voltage and electrical current across the load.
A thermoelectric generator behaves much like an ideal voltage source with an internal resistance due largely to the resistance of the thermoelectric materials themselves. The voltage at the load is reduced from the open circuit voltage by the Ohm’s law (V = IR) voltage drop due to this internal resistance. Maximum efficiency is reached when the load and internal resistances are nearly equal because this is close to the maximum power achieved from load matching.
Problems addressed by NABLA
A major challenge for the application of the thermoelectric technology is related to the material’s maximum operating temperature. Thermoelectric materials have a limit temperature that a TEG can experience without damage. Temperatures above this limit will cause irreversible damage to the generating system.
This limitation has lead to serious restrictions in the selection of suitable candidate materials and has prevented TE tech from spreading its application until now. NABLA team have gone one step further developing a system that not only protects TE material from overheating but also allows it for working at its nominal point at all times.
The emphasis on technological innovation has lead to the creation of the experienced NABLA R&D team, which works hard on delivering practical uses of thermoelectric technology. One of its most significant developments so far has been the launch of the Vulcan Force in Spring 2018, the first thermoelectric generator that includes an overheating protection system. This innovative system is protected under patents ES2610507 and PCT/ES2018/070127.