The complementary duo: Enhancing AHU’s with a natural ventilation solution

Posted by Andrew Wright on 14/07/20 10:00

Enhancing AHU’s with a natural ventilation solutionSometimes, even a good HVAC system can be improved.

The effectiveness of a centralised air conditioning system is dependant on a number of factors and can change over time. Upon assessment, it may be the case that a system no longer operates optimally in its environment, and could be combined with another system to enhance its efficiency.

In this post, we illustrate this point, and explain how sometimes enhancing existing systems can be a great solution for industrial buildings.

Identifying inefficient systems

Heat calculations involve a bit of science and educated guesswork.

If for example, you have a machine in a factory, that gets 100KW pumped into it, to get it running, not all of this heat will be dissipated into the building.

Then you have to calculate the amount of heat that will dissipate into the building from all heat-producing equipment.

An existing centralised air conditioning system installed in a 50+-year-old, high tech automotive manufacturer had provided health and comfortable conditions for the workforce for many years. However, as summers have become hotter over the recent decade the number of days when the temperature inside the building became uncomfortable each year was increasing.

Our estimation concluded that the total heat load within the building, (made up of internal gains from the plant and processes within the space and the solar gain) was in the region of 3.6MW.

The calculations indicated that the existing AHU system had insufficient capacity to control the temperature within the building during the summer period.

Enhancement not replacement

The introduction of a natural ventilation solution can help to extract some of the hot air that is dissipated into the building, and therefore, reduce the amount of work the existing air handling units have to do.

So the combination of the existing air handling units with the new natural ventilation system:

  • Improves the condition inside the factory for the workforce
  • Reduces the strain on the existing air handling units allowing them to keep the temperature under control

In the example above, we determined that the introduction of a natural ventilation system would enhance the internal environment in the building, by reducing the likelihood of warm air accumulating throughout the building.

We installed 48 of our Colt Seefire louvred ventilators. The installation had no impact on production, which continued uninterrupted.
This solution works alongside the existing air handling units which had only been installed for around five years.

The building’s hundreds of spot welding units generated 3.6MW of heat. We estimated that the cooling capacity of the air handling units was approximately 1.5KW. The Seefire louvred ventilators take care of the remaining 2.1MW.


This solution was a win-win for the client as the installation of the Seefire louvred ventilators did not interrupt production and eliminated the excessive factory temperatures.

Find out more.

Factory Survey

To find out how these units could help improve your working conditions, a survey of your factory is needed to assess your current situation. At Colt, our engineers have been working with building owners and operators solving their problems related to the indoor environment and helping improve their business for over 30 years.  

Request a survey

Andrew Wright - Climate Control Area ManagerAndrew Wright is an Area Manager for Colt's Climate Control divison, experienced in creating efficient ventilation systems to achieve comfortable working environments and increasing productivity.

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Topics: Factory Survey, Climate Control