Cooling Technologies

Calyos Proprietary Technologies

Calyos proprietary technologies are capillary loops with the following common characteristics:

  • High thermal performance for advanced cooling applications

  • Large cooling capacity (W to KW)

  • Can deal with high heat densities (>100W/cm²)

  • Long distance (meters) heat transfer capacity (thanks to vaporization & capillary pumping effects)

  • 100% passive loop (good reliability and extended lifetime)

  • Several working fluids options including dielectric fluids with low latent heat of vaporization capability

  • Rigid or flexible tubing

  • Can be connected to air, water or solid (cold plate) heat exchangers

  • Can operate against gravity (capillary pumping)

In addition to these common characteristics, each architecture has its own features as explained below.

Loop Heat Pipe (LHP)

+ LHP features:

  • Multiple customization opportunities

  • Opportunity to combine multiple heat sources in series on a single heat exchanger (multi stage LHP)

  • Operating as a thermosyphon further increase the thermal performance

Capillary Pumped Loop (CPL)

+ CPL features:

  • Evaporators can be in parallel

  • Balance multiple heat sources at the same operating temperature

  • Fine control of the operating conditions independently of the cold source variation

  • Low temperature operation capability thanks to passive pressurization (patent)

  • Need an external reservoir

Capillary Jet Loop (CJL)

Last Calyos patent

Last Calyos patent

+ CJL features:

  • Thermal bus function. Multiple sources with capillary or simple heat exchanger(s) can be linked to a unique tube

  • Cooling capacity can be independent of the acceleration effect

  • Compatible with aluminum

  • Manage multiple heat sources at the same operating temperature

Bulk cooling

+ Bulk cooling features:

  • Heat recovery from multiple heat source via immersion cooling

  • Condensation resulting from immersion cooling triggers vaporisation effect

Standard Technologies

Aluminum Heatsink

  • Entry level thermal performance for low power applications

  • Robust and capable to resist to strong environmental constraints

  • Passive

  • Gravity independent with fans

  • Weight & volume constraints to maximize performance (extended exchange surface)

  • Can operate either with forced or natural convection

  • Maintenance limited (clogging)


  • Short distance heat transfer capacity

  • Passive – No mechanical part

  • Competitive thermal performance

  • Has to be connected to a heat exchanger

  • Limited by gravity (or acceleration) when the condenser  is below the evaporator (weak pumping head)

  • Cannot be flexible

  • Might suffer from « dry-out » at low temperature (<10°C)

Embedded Heatsink

  • Extended heat transfer surface to maximize thermal performance

  • Better thermal performance in a thermosiphon configuration

  • Weight & volume constraints to maximize performance (extended exchange surface)

  • Might suffer from « dry-out » at low temperature (<10°C)

Vapor Chamber

  • Spread high heat densities (hot spot) to lower the thermal performance requirements of the cooling device side

  • Passive - No mechanical part

  • Low profile device (several mm)