Natural gravity ventilation is the best cooling solution. The benefits of natural ventilation in large industrial buildings are clear and well accepted: no electricity is needed to operate the system, as it simply uses the energy present in the warm air – and there is plenty of this in a glass factory – and this buoyancy-driven airflow is virtually maintenance free. You can read more about the benefits of natural ventilation in our previous blog post: Natural ventilation is the solution for most heat intensive industries.

1. Cooling glass factories: ventilation is a tricky business
Natural gravity ventilation is the best cooling solution
The benefits of natural ventilation in large industrial buildings are clear and well accepted: no electricity
is needed to operate the system, as it simply uses the energy present in the warm air – and there is
plenty of this in a glass factory – and this buoyancy-driven airflow is virtually maintenance free.
You can read more about the benefits of natural ventilation in our previous blog post: Natural
ventilation is the solution for most heat intensive industries.
The issue with ventilating glass factories
This said, ventilation in glass factories has always been a hot issue. You need to evacuate the surplus
of thermal energy generated by the oven, at the hot end of the factory. However, if this isn’t done
exactly right, it might create air currents in the cold end of the factory depositing dust on the brand new
glass – a big concern for the quality of your product. Please see below for images which illustrate this
point.
A well-engineered system is the answer
To safeguard the quality of your production, it is important that you rely on experts with specialist
experience in the glass industry to design your ventilation system. Every building has its own
characteristics and dynamics, depending on its shape, layout and the distribution of the production
equipment within the factory.
It is critical that the designer has the capacity to get a clear picture of the airflows in and around the
building in order to ensure the system efficiently evacuates excess heat from the hot end without
creating undesired currents at the cold end. Computational Fluid Dynamics (CFD) simulations carried
out by experienced engineers have proven to be invaluable tools to develop and validate a well
engineered system.
Call in the experts
At Colt we have a long history of designing ventilation systems. We have studied a vast number of
factories that house production processes that generate extreme heat, such as smelters and glass
factories. Over the years we have taken measurements in a wide variety of ambient conditions and
completed a large number of CFD analyses, gaining the experience that enables us to get the best
possible match between our simulations and the actual measurements.
If you would like to evaluate the ventilation system in your glass factory or install a new one, why not
get in touch with us and request a free consultation?
© 2013 Colt International Licensing Ltd.

2. Here is a section through a glass factory showing the oven area. In this part of the building heat load is
significant, sometimes in excess of 20 MW. Natural ventilation allows massive release of heat to the
outside.
But air leaving through the ventilators needs replacement inlet air. At the cold end there needs to be
sufficient inlet ventilation
The NPP (Neutral Pressure Plane) in this kind of building is high up because of the lack of inlet
openings high enough below the roof in the oven area. Any opening below that line could lead to
undesired air currents high up in the roof space spreading fumes and dust to where we don’t want it at
all – and that’s in the cold end.
© 2013 Colt International Licensing Ltd.

3. We can use CFD simulations to solve these kinds of problems. We would look to enlarge the
openings, spread them along the length of the building and make their operation automatic.
© 2013 Colt International Licensing Ltd.