How to Design a TEC Cooling System | TEC Module, Heat Sink, Sensor & Mounting Stack Guide

White Paper AWP-TECC-03 · Rev 2.9 · June 2026 · Analog Technologies, Inc.

How do I design a TEC cooling system?

Designing a TEC cooling system is a six-step process: characterize the cold-side thermal load, define the worst-case ambient envelope, select a TEC module from its datasheet performance curves at the actual operating point, size the heat sink for the resulting hot-side heat, choose the sensor placement and mounting, and validate the assembled stack against a worst-case test envelope before production. The TEC controller is selected separately per companion paper AWP-TECC-02.

Four components must be sized together against the application's thermal load, ambient envelope, and target setpoint: the TEC module (heat-pumping capacity at worst-case ΔT), the heat sink (Q_hot rejection at worst-case ambient), the temperature sensor (placement that determines what the loop can resolve), and the mechanical stack (TIM, compression, orientation, sealing).

Starting design path by application

Six-step TEC cooling system design methodology

1. Determine the cold-side thermal load. Q_load = Q_active + Q_passive at worst-case operating point. Active loads include laser diodes, GPUs, photodetectors. Passive loads are heat flowing into the cold object via convection, conduction, and radiation.
2. Define temperature requirements. Setpoint, worst-case ambient at heat sink, and required ΔT across the TEC.
3. Select the TEC module. Read I_TEC and V_TEC from datasheet performance curves at the operating point. Use 60–70% of I_max for general OEM (practical sizing), or 25–30% for battery / long-life applications (high-COP).
4. Match controller to TEC. Controller I_max ≥ 1.5–2× I_TEC; V_max + supply rail must cover V_TEC + V_dropout at worst-case hot ambient. See companion paper AWP-TECC-02.
5. Choose design priority. Minimize input power, minimize size/cost, maximize ΔT, or autonomous enclosure cooling — each maps to a different ATI family.
6. Size the heat sink. R_θSA ≤ (T_hot,max − T_ambient,max) / Q_hot. Apply 1.5–2× margin for lab/production, 2–3× for industrial OEM, 3–5× for outdoor or dusty environments.

Sensor placement and sub-10 mK design rules

Controller datasheet stability is measured at the sensor under defined laboratory conditions. Stability at the controlled object depends on the full thermal stack. For sub-10 mK (<0.01 °C)-class targets:

• Controller placement — well-ventilated; body-temperature drift translates to setpoint drift.
• Topology — prefer hybrid or well-filtered switching over pure-linear.
• Heat sink — constant fan speed; no variable airflow on load or sink; enclose to exclude external drafts.
• Sensor — small NTC bead, thin leads, within 5 mm of the load, in a step (counter-bored) hole, not a straight through-hole.
• V_PS and TMS pin — manage low-frequency drift and audio-band noise; TMS noise converts directly to temperature command error scaled by V/°C.

TEC mounting and assembly

A poorly assembled stack can lose 20–40% of cooling capacity to parasitic resistance at TIM interfaces. Apply thin uniform TIM (target 25–100 µm) on both ceramic faces. Lap mating surfaces flat to ±0.025 mm (TIR ≤ 0.076 mm). Use four screws with spring washers for uniform compression (typical target 1.0–2.0 MPa over ceramic-face area — verify against the specific module's datasheet).

TIM thickness and per-interface thermal resistance

Recommended ATI controllers by application

Why ATI for OEM TEC cooling systems

ATI's hybrid topology (U.S. Patent 6,486,643 B2) delivers high efficiency together with low output ripple in a single module — substantially reducing the external LC filtering that pure-PWM controllers require, while avoiding the controller self-heating penalty of pure-linear designs. ATI supplies matched TEC controllers, TEC modules, precision thermistors, and evaluation boards from a single source, simplifying compatibility checks across the controller-sensor-TEC operating envelope. US-based applications engineering reviews qualified OEM project specifications and recommends a starting controller family, precision grade, and evaluation board.

Contact ATI

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