What is the figure of merit ZT?
The dimensionless figure of merit, ZT = S2ρ−1κ−1T, is calculated from the Seebeck coefficient (S), electrical resistivity (ρ), and thermal conductivity (κ).
How is ZT calculated?
This complicates the calculation of the ZT value. In the simple definition equation: ZT = Seebeck coefficient squared * absolute temperature * electrical conductivity / specific thermal conductivity the material values must be taken into account as a function of temperature and time.
What is the importance of ZT value in thermoelectric materials?
where ρ, κ, S are the electrical resistivity, thermal conductivity and Seebeck coefficient, respectively. It should be noted that a thermoelectric material with larger value of ZT shows a better thermoelectric influence that generally causes greater efficiency by a thermoelectric device.
What are thermoelectric properties?
A typical thermoelectric material should have high electrical conductivity, low thermal conductivity and thus must maintain a temperature gradient. The Seebeck coefficient is an intrinsic property of the materials related to their electronic properties and independent of their geometry [13].
How do you calculate Seebeck voltage?
thermoelectric generators generated voltage (V) is the Seebeck voltage and is related to the difference in temperature (ΔT) between the heated junction and the open junction by a proportionality factor (α) called the Seebeck coefficient, or V = αΔT.
What is the significance of figure of merit?
A figure of merit is a quantity used to characterize the performance of a device, system or method, relative to its alternatives. In engineering, figures of merit are often defined for particular materials or devices in order to determine their relative utility for an application.
What is an example of thermoelectric?
Some examples of thermoelectric generator applications include biomass cooking stoves, camping stoves and grills. Solar thermal applications utilize solar energy that is concentrated onto a thermoelectric generator hot side at very high temperatures. The ambient air is used for the heat sink.
What is thermoelectric diagram?
Thermo-electric Diagram. A diagram indicating the change in potential difference for a fixed difference of temperature between different metals at different temperatures. It is laid out with rectangular co-ordinates. On one axis temperatures are laid off, generally on the axis of abscissas.
What is a TE device?
A TE module is a device composed of thermoelectric couples (N and P-type semiconductor pellets) that are connected electrically in series, in parallel thermally and, fixed by soldering, sandwiched between two ceramic plates. The latter form the hot and cold thermoelectric cooler (TEC) sides.
How do you measure Seebeck coefficient?
Seebeck coefficient is measured by measuring the upper and lower temperatures T1 and T2 with the thermocouples pressed against the side of the sample, followed by measurement of thermal electromotive force dE between the same wires on one side of the thermocouple.
Can Seebeck voltage be measured directly?
A Seebeck voltage cannot be measured directly. The Seebeck effect is a thermoelectric effect where continuous current is generated in a circuit where the junctions of two dissimilar conductive materials are kept at different temperatures.
How do I make a figure of merit?
The process is a nine-step procedure as follows:
- Definition of New Measure (FOM)
- Why Selected.
- Survey Customers for Needs and Expectations.
- Brainstorm factors.
- Sort ideas into groups.
- Create group header definitions.
- Prioritize groups.
- Construct Factor Weighting Value Tables: