Atrium - Criterion 3 failure

[design]

I am modelling an office building with a central atrium with 200m2 rooflight. The room is mechanically cooled and is failing Part L2A criterion 3 'Solar Gains'.

If the atrium is divided into ground floor circulation space and the upper zone as 'internal void or warm roof' then it passes the solar gains check.

I wanted to confirm if this is allowed under Part L and EPC calculations.

My concern is, the room type 'internal void' has no heating/cooling and there is no solar gains check, therefore it passes by default.

The atrium can be modelled in three different ways:

1) One zone with 'circulation' room profile and appropriate heating cooling
2) Two zones with 'circulation' room profile and appropriate heating cooling and different lighting
3) Two zones with 'circulation' room profile for ground floor and 'internal void' for upper zone (with rooflight)

Please advise if option3 is correct way of modelling.

Thank you in advance.

[Wasted Energy]

The issue here is the mechanical cooling which is the trigger for the Crit 3 test.

If mechanically cooling is provided to the atrium, then I can't see how you could possibly define the upper part of it as an 'internal void', even if the cooling is at low level only.

In effect you would be attempting to defeat the very purpose of the regulation; to reduce the cooling load due to solar gain to an acceptable level.

I would suggest the way forward would be to look at the g-value of the glass - check what has been allowed for - and see if it could be improved.

W