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Loop Heat Pipes

The only 100% passive alternative to active (pumped) water cooling.
pump & water free

We remove the risk of damage from costly water leaks using a dielectric fluid. Downtime is also reduced by removing the need for a pump.

ultra efficeint

By vaporizing a fluid our systems have the potential to be the most efficient form of heat transfer. For you this means the lowest thermal resistance.

self regulating

Our systems simply operate when heat is applied, adjusting their performance depending on the amount of heat to dissipate. There is no control system to potentially breakdown or fail.

Anti gravity

LHPs are unique in their ability to operate against accelerations. This provides one of the only passive, two-phase solution to operate under such conditions.

fully Scalable

Our systems can scale to your requirements. It doesn't matter the number of heat sources, thermal power, transport distance, or physical size.

100% Passive

The beauty of two-phase is the ability to harness the latent heat of vaporization, using it to power the cooling system, making it the most sustainable solution.

loop heat pipes

how do they work?


capillary pump

The porous wick structure inside the evaporator absorbs the incoming liquid and pumps it towards the baseplate creating the capillary pumping force to move fluid around the system passively.



The liquid evaporates as it contacts the baseplate as it is in contact with the heat source and therefore conducting heat. The vapour exits down the vapour line within the mechanical design.



The vapour continues to the cold source and condenses back into a liquid due to the temperature difference. The liquid then flows back to the evaporator down the liquid line.


Return & repeat

This process continues indefinitely when heat is applied to the evaporator baseplate and the condenser (cold source) has a lower temperature than the heat source.

loop heat pipes

our innovation

Our ability to innovate is fundamental to our mission. Applying our world-leading two-phase knowledge and experience we design the best passive thermal management solutions.

Wick Structure

The wick structure, including a patented micro-layer are the critical elements Calyos has mastered and they provide the best pumping capability of any LHP evaporator made today.


Calyos typically use a safe, green, dielectric refrigerant r1233zd(E) as its Global Warming Potential is <1. Plus we have experience using other fluids as required for different applications.


Our skillset is in customizing two-phase solutions enabling maximum performance while ensuring they are non-invasive and easy to adopt, with features like two-sided evaporators.

loop heat pipes


loop heat pipe for data center racks


Calyos aims to accelerate the sustainable transition of data centers from air cooling to full liquid cooling, notably enabling heat recovery capabilities. The inevitable next step for our product development is to transition our technology from single server to full rack cooling.

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loop heat pipe for data center servers


Our trusted flagship technology has long been deployed in server environments and more recently we have expanded into the telecommunications market. Calyos utilises standard components to build a solution specific to your mechanical design, with our inherent fit-and-forget reliability.

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loop heat pipe for power electronics


Utilizing our flagship technology, our solution offers the only passive alternative to direct water cooling. It is ready for the latest, high-heat density (GaN & SiC) components and can be deployed either by combining with, or by replacing an existing cooling system. Our solution provides an ultra-reliable, maintenance free, long-lifetime power electronics cooling solution.

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loop heat pipe for embedded electronics


This is the most flexible solution for cooling embedded electronics on the market. Ultra reliable and maintenance free, our solution is ideal for even the most harsh environments. The system is able to access any remote cold source no matter the size or type.

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LHP vs water cooling

up to


less power

Our totally passive heat transfer system requires no fans and no pumps - saving battery power for critical usage.

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No pumps, no water, no short-circuits, no problems. Our systems are designed to be maintenance free.

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less weight

Less components = less weight. This ensures maximum range and can create more space for power systems.

Let's Get Started

Schedule an introductory call with a Calyos heat pipe expert.

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