In my opinion, a natural ventilation system should always be the first choice for power plants, energy from waste, biomass, hydro stations, transformer stations and other similar buildings for 2 reasons:

1. Why natural ventilation is best for power generation facilites: The facts
and figures
In my opinion, a natural ventilation system should always be the first choice for power plants, energy
from waste, biomass, hydro stations, transformer stations and other similar buildings for 2 reasons:
1) The Environment
The number and frequency of extreme weather events has been on the increase throughout the world.
The climate is changing, of that there is no doubt, and the most popular theory is that this is due to the
rise in CO2 emissions.
We all know that natural systems use less energy than mechanical systems, but have you ever
quantified the environmental impact? Let’s look at a project example - a typical biomass boiler hall with
a 500kW heat load. In this instance:
A mechanical ventilation system would require an extract fan rated at 22m3/s with a 24kW motor.
This extract fan will use approximately 157,680kWh of electricity per year (assuming that the system
will be operating 75% of the time).
Using the Carbon Trust conversion factor, this extract fan would generate 70,243 kg of CO2e per year.
A mature tree can absorb approximately 24kg of CO2 per year.
Therefore it would require 2,927 mature trees to absorb the CO2created by this mechanical extract fan
every year!
A natural ventilation system would create no CO2 emissions!
2) Cost
Keeping with the example above, let’s now compare costs:
Supply and Installation Cost
Mechanical Ventilation - £25,000
Natural Ventilation - £50,000
Running Costs
Mechanical Ventilation - £15,768 per year (assuming 10p per kWh)
Natural Ventilation - £0 per year
Combined Cost over 5 Years
Mechanical Ventilation - £103,840
Natural Ventilation - £50,000
© 2013 Colt International Licensing Ltd.

2. Conclusions
Natural ventilation is not only better for the environment, but it will also save your client money – and
probably a lot of it over a 25 year period!
Designing a natural ventilation system can be a daunting task. Weathered, attenuated and controllable
ventilation is normally required for such buildings. It can be a complicated process to calculate the Cv
(coefficient) of the combined equipment and determine the number of ventilators and their position to
meet the design requirements, so we recommend that you take advice from a natural ventilation
specialist. They should be able to offer free design (make sure it includes guarantee of performance),
CFD modelling, product selection/sizing/integration, and controls.
If you want to know more, you can find further information in our other articles on ventilation relating
to power generation facilities, or contact me using the links below.
© 2013 Colt International Licensing Ltd.