Overheating in corridors: when natural ventilation is not enough, evaporative cooling comes to the rescue

Posted by Paul Compton on 08/07/14 11:30

In previous articles we wrote about how you can solve overheating in residential buildings’ common areas by using the smoke control system to provide simple and effective cross flow ventilation and extract warm, stale air from these spaces. However, there are cases when this won’t be enough and the system will need some help to lower the temperatures to the desired level.

Boost the cooling effect with evaporative cooling

A ventilation system supplying untreated outside air can achieve temperatures in the corridor 3 to 5 degrees above the outside ambient. If this is still too hot, evaporative cooling can provide the solution to boost the effect with active cooling.

At Colt we have developed a solution that uses evaporative cooling technology to provide active pre-cooling of the incoming air and, if there is a fire, it is able to ventilate the common area effectively to allow the smoke to escape. Our CoolShaft smoke and day-to-day shaft system is able to reduce temperatures in common areas to below the outside ambient by providing active cooling in the corridors.  

Economical, energy efficient, a lightweight space saver

The CoolShaft system is 4 to 7 times more economical than conventional air conditioning, with lower initial costs. It runs most of the year in free cooling mode, with evaporative cooling kicking in when temperatures soar. It only needs a small quantity of electricity for the fan and the water pump, and you can cool several floors with just one unit. And, last but not least, it takes up little space and is much lighter than an air conditioning system.

Further reading

The issue of overheating in common areas of residential buildings is becoming increasingly relevant, and is receiving growing coverage in our industry’s publications. In fact, the July 2014 issue of the CIBSE Journal covers the topic in a comprehensive feature article authored by myself. You can also read our previous blogs addressing overheating in residential buildings.


If you want to know more about preventing overheating in your building with a dual purpose shaft system, you can view our recorded webinar on the topic. The webinar is CPD accredited so you will able to claim a certificate after watching.

Paul Compton Paul Compton is Technical Director for Colt, experienced in smoke control, HVAC, solar shading and louvre systems.

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Topics: Natural ventilation, Overheating, Corridor ventilation, Evaporative cooling