In most cases, natural ventilation is the right answer for power generation plants. However, there are instances where mechanical ventilation may be the best choice.
When is natural ventilation not the answer?
- Not enough height - When the building doesn’t provide enough height to achieve a good stack effect.
- Not enough internal gain - When there isn’t sufficient internal gain to generate temperature gradient;
- Not enough low level space - When there isn’t enough space at low level to provide for the required inlet area: with natural ventilation, the pressure differential across the inlet or extract system must not be too high, or it won’t work effectively;
- No direct access to outside - When the building is entirely or partially enclosed within a main structure, so that there is no direct access to the outside and therefore it is impossible to provide openings for natural ventilation. This is sometimes the case for turbine halls.
As a designer, which factors should you consider for mechanical ventilation?
First of all, the ventilation system you select must ensure that the maximum temperatures that allow efficient operation of the plant and provide comfortable working conditions, are never exceeded. Starting from this premise, you should consider:
- The amount of air, inlet and extract, that will be needed, and how to get it in and out; for example, whether it will need to be ducted.
- The system you select must ensure good distribution.
- Noise: the system should not add to the noise levels within the building or in the surrounding area.
- Natural or mechanical inlet: to use a natural inlet, the pressure drop must not be too high or it will affect the effectiveness of the overall system.
- Running costs
- If the system will also be used for smoke ventilation, you will need to provide the correct rating.
If you want to know how to determine whether natural or mechanical ventilation is the right answer, you can read our blog post When is natural ventilation the right solution for power plants?
Graeme Clark is a Senior Consultant for Colt UK and specialises in the design and product application of energy efficient HVAC and smoke control systems.