Our Core Technology

Reimagining the design of a traditional fin and tube commercial heat exchanger led us to the Fluid Fin Panel (FFP).

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The Fluid Fin Panel Array you see here is the product of an evolutionary design process. We critically examined traditional models and challenged existing ideas to develop our own uniquely efficient product.

Much like Goldilocks, the DEXT team worked through three different options to find the solution that was just right...

Iteration 1:

Tube Coil

A Tube Coil Heat Exchanger transfers heat between the air and fluid via the wall of the tubes. The fluid flows through a series of tubes, while the air passes over the tubes, transferring heat energy to the fluid.


This design has a simple thermal resistance pathway, where the resistance is determined by the tube material’s thermal conductivity, the thickness of the tube wall, and the heat transfer coefficient between the fluid inside the tubes and the surrounding air. This offers several advantages, including simplicity, ease of manufacture and cost efficiency.


Using a simple flow regime with non-turbulent flows results in low heat transfer coefficients for both air and fluid flows. To compensate for this, more tubes can be added, and flow rates can be increased, but this can lead to reduced fouling resistance, increased pressure drop, and increased specific fan power requirements.

Iteration 2:

Finned Tube Coil

The Finned Tube Coil Heat Exchanger was initially created to enhance the performance of the Tube Coil Heat Exchanger through the introduction of extended surfaces (Fins). As a result, this design employs a more intricate thermal resistance network.


The increased surface area and complexity of the thermal resistance pathway in a heat exchanger result in a higher potential for fouling, air side pressure drop, and increased specific fan power requirements.


The extended surfaces (fins) increase the heat transfer area and alters the air flow patterns, resulting in a more complex thermal resistance pathway. More complex external flow regimes create turbulence and higher heat transfer coefficients for the air flow pathway. This, combined with the increased surface area, results in improved thermal performance and a reduction in overall tube lengths and fluid pressure drop.

Iteration 3:

Fluid Fin Panel Array

We carefully considered heat transfer rate, pressure drop, and overall surface area to create our unique Fluid Fin Panel (FFP) array. We took the best design features of Tube Coil and Finned Tube Coil Heat Exchangers, and went a step further to develop a solution that reduces particle resistance on the air-side.

Our innovative solution delivers an application-specific product that actively resists fouling.

This system has been developed, optimised and validated through a rigorous research and development pathway to create the most practical and efficient design.

Advanced geometries both air-side and fluid-side introduce turbulence into the airflow and fluid flow pathway. The result is an increased heat transfer rate.


The system facilitates efficient heat exchange between air and fluid by utilising a simple thermal resistance pathway, which enhances high heat transfer coefficients between the fluid enclosed within the Fin Panels and the surrounding air. The fluid and air circulate through a complicated network of internal and external passages, consistently altering direction and generating turbulence. This design improves fouling resistance, reduces pressure drop, and lowers specific fan power requirements.


For users? None. For Dext, the disadvantage of this design was that it required us to go back to the drawing board and carry out extensive, in-depth research & development, testing, and validation; requiring significant investment and several years of hard work. The result was exceptional though, thanks to Dext’s determination and the support of a UKRI research project.

This is the core technology at the heart of DexThermic, our next-generation heat exchanger, and we believe it has the potential to revolutionise the field.

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