Free cooling - natural ventilation - macro flow

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simonemiri3
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Joined: Tue Oct 15, 2013 8:09 am

Free cooling - natural ventilation - macro flow

Post by simonemiri3 »

Hi,
I'm new of this kind of argument,
I'm modelling a multifloor office building with a big central empty zone with openable windows on the roof and on the ground floor.
On vista I can find three different categories:
- Free cooling
- Natural ventilation
- Macro flow ventilation
What's the difference between this?
What's the correct way to simulate Free cooling in a temperature range?

thanks,

Simone
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Complex Potential
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Posts: 467
Joined: Wed Jan 09, 2013 11:57 am
Location: Bristol, UK

Re: Free cooling - natural ventilation - macro flow

Post by Complex Potential »

Hi Simone

Free Cooling
Really only meant for air conditioned spaces: this should bring air in only when beneficial (ie, when the outside air temperature is below the cooling setpoint)

Natural Ventilation
Defined within the air exchanges tab this is basically a way to bring in air in any way you want so long as you can write a rule for it but it behaves more like machanical ventilation in that it sticks to your defined flow rate and control profile.

Macroflo
Allows you to define actual openings in the facade applied to windows and doors. This means you tell IES how much a window opens and when and then Apache dynamically works out the air flow based on wind direction, speed pressure etc. In theory this is the most realistic way of modelling natural ventilation and it sounds like the most appropriate way in the case you describe, but it is also the method which takes the most practice to get right.

CP
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