What happens when I make my zone 'Unconditioned'?
In the zoning tab, you can select the Internal Conditions for each zone. When you select 'Unconditioned,' the zone does not receive any zone heating/cooling but continues to receive internal loads such as equipment, lighting and occupancy.
So, the zone has been assigned 'Unconditioned' is not yet a zone such as a riser or garage, it contains the internal loads which are active in the Internal Conditions tab.
To create the conditions for a riser/storeroom/garage/warehouse go to the Internal Conditions tab and input the appropriate values. Then apply this template to the zone.
Here is an example of a single storey, 4 zone building with no drawn glazing;
Here is the model setup as an Office profile, in London, UK and with Part L 2013 Notional Building envelope values applied.
Here is that same model uploaded to the web application and 40% WWR applied across each facade except for the East facade where we have specified 25% WWR ratio in Sefaira.
Each of the 4 zones was assigned conditions and conditioning as per the default 'Office' profile.
Here are the Peak Cooling loads per zone
Then, the user can turn off conditioning in the zones P01, P02 and P03
Resulting in the Peak Cooling loads per zone shown below;
These are the overall results for the building now that one zone is 'Conditioned' and three zones are 'Unconditioned'
Why are the results this way?
AHU Design Airflow
As the 'Conditioned' floor area has reduced from 1,302 m2 to 58 m2, and the AHU Design Airflow is specified in litres/m2 per second the value will reduce when three zones are removed from the conditioned floor area.
Cooling Equipment Design Capacity
Similarly, as the 'Conditioned' floor area has reduced from 1,302 m2 to 58 m2, and the Cooling Equipment Design Capacity is due to the coincidental peak load across the whole building the value will reduce when three zones are removed from the conditioned floor area.
As EUI is an annually calculated figure, rather than a peak from a design day or hour, and as the 'Conditioned' floor area has reduced from 1,302 m2 to 58 m2; the EUI will change but it is also per unit area so will not change proportionally to the reduction in floor area as other peak values might.
Here is the cost breakdown with all zones conditioned;
And here is the cost breakdown with only one zone conditioned;
You will notice that the Lighting and Equipment cost has not changed. This is because we have only removed the zones from Conditioning by the HVAC system not from assigned Internal Conditions loads. This is a common misconception and should be noted to avoid confusion.
In the example outlined, the change in cost is from HVAC cost reductions but the Internal loads remain the same.
For any questions please contact firstname.lastname@example.org