CALCULATORS / HEAT TRANSFER AND TEMPERATURE

Thermoelectric hot-side heat rejection calculator

Supplied operating-point cooling capacity, power and hot-side resistance; no TEC curve solve.

thermal-thermoelectric.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	rejectionW	cop	hotTemperaturedegC
	50	0.666667	50
	46	0.533333	48

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

hot side temperature budget50.00 degC✓ passes

BASELINE INPUTS

cooling20 Welectrical30 WhotResistance0.5 K/Wambient25 degC

CALCULATED

rejection50 W

cop0.66667

hotTemperature50 degC

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Thermoelectric cooler operating-point screening
# Scope: Supplied operating-point cooling capacity, power and hot-side resistance; no TEC curve solve.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

cooling = 20 W
electrical = 30 W
hotResistance = 0.5 K/W
ambient = 25 degC

rejection := cooling+electrical [W]
cop := cooling/electrical
hotTemperature := ambient+rejection*hotResistance [degC]

check hot side temperature budget: hotTemperature <= 60 degC

scenario alternative: cooling = 16 W

Calculated from your source · not saved

Baseline · Baseline

hot side temperature budget50.00 degC ✓ passes

alternative · alternative

hot side temperature budget48.00 degC ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

rejection: rejection = cooling+electrical [W]
cop: cop = cooling/electrical
hot temperature: hotTemperature = ambient+rejection*hotResistance [degC]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

cooling: 20 W
electrical: 30 W
hot resistance: 0.5 K/W
ambient: 25 degC

Calculated

rejection: 50 W
cop: 0.666667
hot temperature: 50 degC

Assumptions and limits

Supplied operating-point cooling capacity, power and hot-side resistance; no TEC curve solve.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Thermoelectric cooler operating-point screening. Inputs: load; temperature lift; calibrated device curves; sink resistance. Outputs: power demand; achievable temperature range. Model scope: Lumped or low-dimensional thermal models with explicit properties. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: load, temperature lift, calibrated device curves, sink resistance
Outputs: power demand, achievable temperature range
Modes: calculate, compare, sweep
Drawing: Temperature and heat-flow plot

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS