Comhex©, the reliability of stainless steel heat exchanger

General description

Operating principle


New materials developments

General description of  the Comhex© stainless steel heat exchanger

The Comhex© stainless steel heat exchanger has an innovative design to enhance heat transfer and compactness.
The figure below gives a sight on the Comhex© general structure. It consists of an accordion-like sheets called “HED” sandwiched between flat plates called “feeder”.  The mechanical cohesion is assured by brazing all together.



Overall view of Comhex

01 HED

The HEDs, for “Heat Exchange Device”, are corrugated accordion-like sheets of stainless steel, with thin walls. HEDs are the true heart of Comhex©, where the heat transfer between the two fluids takes place. Microchannels are between the wrinkles of the HED. The number of HEDs and feeders depends on the flow, pressure drop and power requirements.

02 Feeder

The feeder plates enable fluids to get in and out of the microchannels. They are customised.

03 Header

The headers bring the fluids from the outer installation to the feeders. Their dimensions are chosen to suit the connections to the system.

04 End Plate

On both up and bottom sides of the Comhex©, stainless steel end plates are brazed to seal the main structure.

05 Cap

In order to assure a leak-free heat exchanger, caps and headers are welded together. As the other pieces, caps are made of stainless steel 316L in order to prevent galvanic corrosion.

06 Sealing layer

A  patented sealing layer wraps up the main structure to assure the tightness of Comhex©.
The number of HEDs and feeders varies according to the flow, pressure drop and power requirements.


Operating principle of  the Comhex© stainless steel heat exchanger

Comhex© works with two fluids exchanging their heat through a primary active surface. Most of the time, it operates counter-flow (co-current flow is also possible).

The operating principle is shown on the figure below:

Operating principle of Comhex©

The fluids arrive through the headers, rush into the feeders where they are distributed in the HED microchannels. On one side of the HED, you have the hot fluid (the lower side on the figure above), and on the other side, the cold fluid (the upper side on the figure above). In this way, hot fluid circulates in a tight rectangular microchannel and transfers the heat to the cold fluid circulating through the microchannels walls around.  Then, fluids leave through the feeder and the headers.

In Comhex©, thanks to the ingenious design of microchannels, both fluids are very closed without any direct contact to provide an intense heat exchange. The heat transfer surface is very high in comparison to the volume occupied by the device. Moreover, adapted corrugations of the HED enhance the heat transfer mechanisms and prevent problems due to a high-pressure difference between the two fluids.

Applications of  the Comhex© stainless steel heat exchanger

The smart design of Comhex© allows a great adaptability in term of power, efficiency, pressure-drop, footprint and weight. Allied to the versatility of stainless steel, it opens a wide range of uses and applications, in many settings. It supports higher operating temperature than copper and offers a good resistance to corrosion. That open a wide area of applications:

  •  Building
  •  Industries
  •  Embedded
  •  Data centers
  •  Electric vehicles thermal management
  •  HVAC
  •  Cooling of electronics

Beyond stainless steel : new materials developments

Stainless steel is the first alloy Comhex microchannel heat exchangers have been made of. However, even if stainless steel heat exchangers have many advantages, the use of other alloy opens new possibilities of applications or a better fitting to the costumers’ requirements.

  •  Comhex© Cu copper heat exchangers for marine applications
  •  Comhex© Al aluminium heat exchangers for automotive applications including a focus on the thermal management of electric vehicles (Li-ion batteries, electronics, engine, connections)

To find out more about our ultra-compact heat exchangers, you can contact our experts. Be sure they will put all their know-how at your disposal. You can draw on our broad knowledge to support you in your projects, even the most specific. We are eager to conceive the custom solution that suits to your requirements, whatever they are in terms of power, efficiency, pressure-drop or footprint.

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