What Is the Thermoelectric Figure of Merit (ZT) & Efficiency Calculator?
The dimensionless figure of merit ZT is the universal benchmark of thermoelectric material performance, governing heat-to-electricity conversion efficiency.
How Does the Thermoelectric Figure of Merit (ZT) & Efficiency Calculator Work?
Combines the electrical power factor (S² * sigma) with average absolute temperature divided by thermal conductivity kappa.
Thermoelectric Figure of Merit (ZT) & Efficiency Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
ZT = rac{S^2 sigma ar{T}}{kappa}, quad eta_{ ext{max}} = eta_{ ext{Carnot}} left[ rac{sqrt{1 + ZT} - 1}{sqrt{1 + ZT} + T_c / T_h}
ight]
Thermoelectric dimensionless figure of merit ZT and maximum conversion efficiency.
How to Use the Thermoelectric Figure of Merit (ZT) & Efficiency Calculator
- Input Seebeck coefficient in µV/K, electrical conductivity in S/m, thermal conductivity in W/m·K, and hot/cold temperatures in Kelvin.
Step-by-Step Example Calculation
Bismuth Telluride / Lead Telluride Alloy
Input Values:
seebeckCoeffUvK:215
electricalConductivitySPerM:95000
thermalConductivityWPerMK:1.35
tempHotK:580
tempColdK:300
Worked Steps: Figure of Merit ZT = 1.43, Carnot limit = 48.3%, Maximum thermal conversion efficiency = 9.87%.
Understanding Your Result
Displays ZT value, maximum achievable thermal efficiency %, and theoretical Carnot limit.
Factors That Affect the Result
- High ZT requires high electrical conductivity with simultaneously low thermal conductivity (the "phonon-glass electron-crystal" paradigm).
When Should You Use This Calculator?
- Spacecraft radioisotope thermoelectric generators (RTG), automotive exhaust waste heat harvesting, and solid-state Peltier cooling.
Assumptions & Limitations
- Assumes temperature-averaged constant thermoelectric transport properties.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard Ioffe thermoelectric efficiency formulation.