Heat Pipe Resources

More Information:

If you are designing a thermal system and simply want to learn more about heat pipes for cooling, use the links in the Operation Section. If you still have questions, contact us and an engineer will be in contact with you.

See a full video and transcription about the basics of heat pipes and their advantages.

Product Links

  • Electronics Cooling

    For most terrestrial applications Cu-H2O and Cu-Methanol are used.

  • Aerospace

    Aluminum-ammonia systems are used for spacecraft thermal control.

  • High Temperature

    Using liquid metal as the working fluid allows operation at temperatures up to 1,100 degrees C.

  • HVAC / Energy Recovery

    Wrap around heat exchangers create efficient operation to lower operating costs by pre-cooling incoming air.

  • HiK™ Plates

    ACT’s HiK™ (High Conductivity) plates are heat spreaders with embedded HP to increase the effective thermal conductivity for conduction cooled cards and electronics enclosures

  • Vapor Chamber Assemblies

    Vapor Chambers are very high effective conductivity heat spreaders, as well as a flux transformer, lowering the effective heat transfer rate at the heat sink.


  • How do they work?

    Background physics including a video that demonstrates the two-phase heat transport.

  • Gallery

    Visit a gallery of two phase heat transfer devices.

  • Performance

    Learn about the various limits that determine the maximum power (W) a heat pipe can move.

  • Calculator

    Use this tool to calculate a copper-water heat pipe's capability for your system.

  • Design Guide

    Learn the basics on sizing and modeling with our heat pipe design guide. You'll be able to integrate these devices into your project in no time!

  • Wick Structures

    Learn about the advantages, limitations, and trade-offs of various wick structures.

  • Fluid Selection / Compatability

    Working fluids are determined primarily by the ambient conditions, the thermodynamic properties of the fluid, and compatibility with the wick/envelope.

  • Different Types of Heat Pipes

    Discusses specialized heat pipes and their applications.

  • Fundamentals

    Discusses fundamental operating principles of heat pipes.

  • Modeling

    Learn how to integrate heat pipes into computer models.

  • History

    A short history showing how applications have expanded since the heat pipe was invented back in 1963.

  • Webinars

    ACT’s thermal management video tutorials, including two-phase heat transfer, heat sinks, LED thermal management, and thermal storage. Transcriptions of the videos are available.

New Advancements

  • Technologies

    Over the years ACT has developed many two-phase heat transfer technologies for future applications.

  • High Temperature Water Heat Pipes

    Learn how ACT has extended the operating temperature range for water working fluid from 150 to 300°C.

  • Intermediate Temperature Working Fluids

    ACT is developing new working fluids for the intermediate temperature range, between water and alkali metal working fluids.

  • High Temperature

    Alkali metal working fluids with superalloy envelopes allow operation at temperatures up to 1100°C.

  • Vapor Chambers

    ACT has developed vapor chamber heat spreaders that can accept heat fluxes up to 500 W/cm2 over a 4 cm2 area and transform the heat flux so that it can be removed with conventional cooling methods.

  • Pressure Controlled Heat Pipes (PCHPs)

    PCHPs vary the amount of Non Condensable Gas (NCG) in their reservoir, allowing very tight temperature control (± 5 mK) over hours of operation.

  • Loop Heat Pipes

    LHPs are passive, two-phase heat transport devices that can transfer higher amounts of heat over longer distances than conventional heat pipes.

  • Heat Pipe Loops (HPLs)

    HPLs provide higher heat transport than heat pipes, with lower cost than LHPs.

  • Life Tests

    Life tests are conducted to verify that the envelope, wick, and working fluid in a two-phase heat transfer device are compatible, allowing for long term operation.