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Heat Pipe Selection

350+ off-the-shelf heat pipes
No sign-in required
Start here — what a heat pipe needs from you

A heat pipe is a sealed copper tube with a wick inside and a little water. Heat boils the water at one end, the vapour rushes to the cold end, condenses, and the wick pulls the liquid back. It moves heat — it does not get rid of it. Something at the far end (a heat sink, a chassis wall, a cold plate) still has to dump that heat into the air.

  • Evaporator, Le — the length in contact with your hot device. This is the length most people get wrong. Too short and the wick dries out long before you reach the catalogue Qmax.
  • Adiabatic, La — the middle. Carries heat, exchanges none.
  • Condenser, Lc — the length buried in the heat sink or cold wall.
  • Qmax — most heat one pipe can carry before dry-out. It falls as the pipe gets longer and as you tilt the evaporator above the condenser.
  • Leff = L − (Le + Lc)/2 — the effective transport length that sets Qmax.
Choose how you want to select
Input — Quick Pick You supply the geometry
Heat load and contact lengths
Total watts the pipes must carry.
Contact length on the hot device or block.
Length buried in the heat sink or cold wall.
Pipe preference
Flat pipes fit under low covers; round pipes carry more per gram.
Sintered works in any orientation. Grooved only works with gravity helping.
Roughly the pipe wall temperature in use. Water pipes are strongest near 60–90°C.
Input — Detailed Selection You supply the temperature target; the tool sizes everything else
1. The thermal requirement
The case or lid temperature you must not exceed. If you only know Tj,max, subtract Q × Rjc first.
Air entering the heat sink.
×
Sets how much evaporator length you can physically lay on the part.
2. The heat pipes
Straight-line length. Add roughly 10 mm of length per 90° bend.
Thicker, softer materials tolerate gaps but cost you temperature.
3. Space and air available at the condenser end

Give the largest heat sink you can accommodate. The tool searches the ATS portfolio for standard parts that fit inside it, and falls back to a custom build only if nothing standard works.

Base plus fins, matching how ATS quotes heat sink height.
Approach velocity at the fin face. 1–2 m/s is a quiet chassis; 4–5 m/s needs a dedicated fan. 1 m/s ≈ 197 LFM.
ATS publishes both. Ducted means the air is forced through the fins rather than around them.
Output
Next steps Optional — nothing is stored unless you ask for it
Results are first-order engineering estimates for component selection, based on ATS published Qmax data and standard heat pipe and fin-array correlations. Confirm the final design with detailed analysis or ATS Applications Engineering: [email protected], +1 781-769-2800.