Thermoelectric Efficiency Calculator

Calculator Inputs

Hot-side Temperature (K)

Cold-side Temperature (K)

Heat Input (W)

Seebeck Coefficient (µV/K)

Electrical Conductivity (S/m)

Thermal Conductivity (W/m·K)

Known Average ZT (Optional)

Thermocouple Leg Pairs

Load Voltage Ratio (0 to 1)

Contact and Parasitic Loss (%)

Leave Known Average ZT empty to calculate ZT from Seebeck coefficient, conductivity, thermal conductivity, and average temperature.

Example Data Table

Hot K	Cold K	Seebeck µV/K	Conductivity S/m	Thermal W/m·K	Heat Input W	ZTavg	Adj. Efficiency %
500	300	220	110000	1.50	180	1.4197	9.49
550	320	240	125000	1.35	220	2.0431	13.06
450	300	180	90000	1.80	150	0.6075	5.30

These rows are sample scenarios for interpretation only.

Formula Used

Power Factor:

PF = S² × σ

S is Seebeck coefficient in V/K, and σ is electrical conductivity in S/m.

Average Figure of Merit:

ZTavg = (S² × σ × Tavg) / κ

Tavg is average temperature, and κ is thermal conductivity in W/m·K.

Carnot Efficiency:

ηc = (Th - Tc) / Th

Th is hot-side temperature and Tc is cold-side temperature, both in Kelvin.

Maximum Thermoelectric Generator Efficiency:

ηmax = ηc × [(√(1 + ZTavg) - 1) / (√(1 + ZTavg) + Tc/Th)]

Adjusted Practical Efficiency:

ηadj = ηmax × (1 - loss%)

This page applies contact and parasitic loss to estimate a more practical efficiency.

How to Use This Calculator

Enter hot-side and cold-side temperatures in Kelvin.
Provide Seebeck coefficient, electrical conductivity, and thermal conductivity for the thermoelectric material or effective module pair.
Enter heat input to the module, leg pair count, load voltage ratio, and expected contact or parasitic losses.
If you already know the material’s average ZT, enter it in the optional field to override the calculated value.
Press Calculate Efficiency to show the results above the form.
Use the CSV or PDF buttons to export the result summary for reports, documentation, or design comparison.

FAQs

1. What does thermoelectric efficiency measure?

It measures how much supplied heat can be converted into electrical output. The percentage compares electrical power produced against thermal power entering the device.

2. Why must temperatures be entered in Kelvin?

Kelvin keeps the thermodynamic relationships correct. Using Celsius directly can distort Carnot efficiency and the temperature-dependent ZT calculation.

3. What is ZT in thermoelectric analysis?

ZT is the dimensionless figure of merit. Higher ZT generally indicates better thermoelectric material quality, because it combines Seebeck response, electrical conductivity, thermal conductivity, and temperature.

4. Should I enter material properties or a known ZT?

Use material properties when you want the page to calculate ZT. Use a known average ZT when you already have lab or vendor data for the selected temperature range.

5. What does the load voltage ratio represent?

It estimates how operating voltage compares with open-circuit voltage. A value near 0.5 is often used for matched-load style estimates.

6. Why include contact and parasitic losses?

Real systems lose performance through interfaces, wiring, heat leakage, and imperfect thermal coupling. This input reduces ideal efficiency to a more practical estimate.

7. Is the calculated power an exact device rating?

No. It is a design-stage estimate based on average properties and simplified assumptions. Actual results depend on geometry, temperature gradients, contacts, and module construction.

8. Can this calculator compare different thermoelectric materials?

Yes. Enter separate property sets for each material or module. Then compare ZT, adjusted efficiency, electric power, and relative performance against the Carnot limit.