Tru Physics

Thermoelectric Effect

—

by

Tru Physics
in

Introduction

The thermoelectric effect refers to a collection of phenomena in which a temperature difference creates an electric potential or an electric potential creates a temperature difference. These effects have important applications in heating and cooling, power generation, and temperature sensing.

Types of Thermoelectric Effects

Seebeck Effect

The Seebeck effect is the conversion of temperature differences directly into electricity. When two different metals or semiconductors are connected to form two junctions, and the junctions are maintained at different temperatures, an electromotive force (emf) is generated. The Seebeck emf V_{S} is given by:

V_{S} = S(T_{H} - T_{C})

where S is the Seebeck coefficient, T_{H} is the hot junction temperature, and T_{C} is the cold junction temperature.

Peltier Effect

The Peltier effect is the reverse of the Seebeck effect. It describes heating or cooling at an electrical junction. When a current is made to flow through a junction of two different materials, heat is absorbed or released. The Peltier heat Q_{P} is given by:

Q_{P} = \Pi I \Delta t

where \Pi is the Peltier coefficient, I is the current, and \Delta t is the time.

Thomson Effect

The Thomson effect describes the heating or cooling of a current-carrying conductor with a temperature gradient. The Thomson heat Q_{T} per unit time is given by:

Q_{T} = \kappa I \dfrac{\Delta T}{\Delta x}

where \kappa is the Thomson coefficient, I is the current, \Delta T/\Delta x is the temperature gradient.

Thermoelectric Modules and Devices

Thermoelectric modules, or thermoelectric coolers (TECs), use these effects to provide precise temperature control. Likewise, thermoelectric generators (TEGs) can convert waste heat into useful electrical power.

Thermoelectric Materials

The efficiency of thermoelectric devices depends on the materials’ thermoelectric properties. Good thermoelectric materials have a high Seebeck coefficient, high electrical conductivity, and low thermal conductivity.

Conclusion

The thermoelectric effect enables direct conversion between thermal and electrical energy. This has applications in power generation, waste heat recovery, cooling systems, and temperature sensing. Despite these promising applications, the relatively low efficiency of thermoelectric devices compared to traditional heat engines or refrigerators means there is significant ongoing research to improve thermoelectric materials and devices.

Do you prefer video lectures over reading a webpage? Follow us on YouTube to stay updated with the latest video content!

Want to study more? Visit our Index here!

Comments

Have something to add? Leave a comment!