Modelling Mech Vent Car Parks in DSM

[Complex Potential]

Hi all

My understanding is that if a building's car park is mechanically ventilated then the specific fan power and lighting energy for that car park need to be accounted for within the Part L model.

My question is how to then define the car park within a DSM or SBEM model to have the notional building behave correctly. As far as I can tell, there are two options:

1) define the car park as a buffer space
2) define the car park as a car park

The problem with 1 is that it then has no allowance for lighting in the actual building and the notional building doesn't model it at all.

The problem with 2 is that the car park must be included as a thermal zone within the model and hence the notional building sees it as within the insulated layer. Since my insulation runs above the car park my model flags up a fail on the ground slab under criterion 2.

Am I missing something?

CP

[RossThompson87]

Hi,

There is some guidance regarding mechanically ventilated car parks in the EPC conventions:

The following should be used in SBEM v3.5 to define an enclosed or underground car park which has mechanical ventilation and therefore requires either its own EPC or inclusion in an EPC.The activity must be set to “circulation”, the HVAC system must be set to “Zones without HVAC system” and the mechanical supply/extract system or the mechanical exhaust system must be used to enter the required “Ventilation” or “exhaust” via the zone level tabs.

I'm not entirely sure how this would apply to DSM but you could try something similar.

I have never really modeled a car park before, but I would take advice from your accreditation body if you are looking at EPCs as you may need to lodge a seperate one for the car park.

I hope this helps

Ross

[Complex Potential]

Thanks Ross

That's basically what I've done but I used the "car park" template rather than the "circulation" one. Given that the heating and cooling systems are switched off regardless and the ventilation is input as room level extra only, the difference between the two will be minimal I think.

Unfortunately that still leaves me with the criterion 2 fail showing up on the BRUKL since it sees the car park floor as the boundary of the thermal envelop which is not the case (the insulating layer is above the car park, naturally).