# Natural Ventilation Control

Dear all,

I would like to know if anybody knows a good way of controlling natural ventilation based on the difference between Indoor and Outdoor temperatures in an energy analysis.

I thought this was how Honeybee Set EP Air Flow worked but apparently not as it still opens the window when T(out) > T(in) (I get positive heat gains in this case).

I basically want to use sensible natural cooling when possible and relevant, i.e. when the 2 following conditions are met :

I know this is possible in EP but I have the feeling it is not yet implemented in HB ? Any help would be greatly appreciated.

Best,

Aurelien

The way I see it, this should be done by creating a custom schedule.

Look at this discussion.

-A.

Devang :

I thought about that but I don’t know T(in) before the simulation, so it would require to run the simulation twice and create a schedule of time when T(in) > T(out) . But then again, this would change the simulation result and thus T(in)… so maybe after a few iteration you could consider that you result is quite good but it makes it quite complicated to run …

Abraham :

I read the discussion, but it does not solve my problem…
The problem is that the component allows you to specify a range for T(in) and T(out) separately but for instance if I want to use natural cooling, then I want to cool when :

T(in) > 24°C IF T(out) < T(in)

For instance, if T(in) = 25°C and T(out) = 26°C, I don’t really want to open the windows, which is what this component does.

Aurelien

Just an update on the situation,

The best way I found right now is to implement several components with a 1°C or 2°C difference between indoor and outdoor temperature, but there is surely a bette way of doing this.
For instance :

one for 25°C> T(in) > 23°C and T(out) < 23°C

one for 27°C> T(in) > 25°C and T(out) < 25°C

one for 29°C> T(in) > 27°C and T(out) < 27°C

etc etc …

But this is quite an ugly solution, so still wondering how we could do it in a better way ! (maybe inputing a series of temperature in one component ?)

Bests,

A