Question

1. How could you use a thermoelectric device as a heater instead of a cooler? (Is a TEG the same as a thermoelectric heater?)

2. What are the prospects for organic semiconductors to be used in thermoelectriv devices?

Answer 1

1.)Peltier heat absorption is given by Q = P (Peltier Coefficient) I (current) t (time). A single stage thermoelectric cooler can produce a maximum temperature difference of about 70 degrees Celsius. The cooling effect of any unit using thermoelectric coolers is proportional to the number of coolers used. Typically multiple thermoelectric coolers are connected side by side and then placed between two metal plates.

Thermoelectric systems are based on the scientific phenomena called the Peltier Effect. According to this phenomenon a temperature gradient is set up when an electric current is passed through the junctions of two conductors. Due to this effect heat is deposited in one junction and cooling occurs in the other junction.Thermoelectric systems are mainly used in cooling devices but it also finds application in heating devices. In both cases DC voltage is necessary.

2.)Thermoelectrics currently attracts considerable attention as a promising branch in the field of organic electronics, with the prospect that organic semiconductors (OSCs) allow the development of light, flexible, and inexpensive thermoelectric devices, which act as alternative power sources, generating electricity from heat gradients. Thermoelectric generators are solid-state devices that convert heat directly to electricity. They do not contain any moving parts and are able to operate over an extended period of time, and furthermore can function with small heat sources and limited temperature differences, which facilitates their use in situations where traditional engines are not feasible. The absence of moving parts, low need for maintenance, and a large variety of possible device architectures render organic thermoelectrics attractive for numerous applications, ranging from waste heat recovery to wearable textiles. In this chapter, we give a short introduction to the fundamentals of the thermoelectric effect, as well as to the design principles for thermoelectric generators and their characterization.