Design Builder - Air Changes per Hour (ACH) input

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Design Builder has a few locations (e.g. infiltration, mech vent)
where ACH is the input. Does anyone know exactly what value they
intended to be used? Specifically, the reference pressure for ACH?
Any insight into this matter is greatly appreciated.

Regards,
Russell

Russell Richman's picture
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Russell,

The ACH data entered in DesignBuilder for infiltration, natural ventilation
and mechanical ventilation simply represents the air change rate that can be
expected to occur during typical operating conditions. This empirical
approach to modelling ventilation is useful for cases where you can estimate
ventilation flows from experience or you wish to use design assumptions.

Alternatively you can of course also model the natural ventilation
calculations in more detail by using the 'calculated' natural ventilation
option which uses the EnergyPlus AirflowNetwork.

Regards,

Andy Tindale

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