A five story Atrium is being constructed in a science building. It is also the main entry into the building and furnished with benches for transient use. There are no desks or offices located in it. The 1st floor “Lobby” was constructed with over 15 btuh/sf heating so it is considered a conditioned space for climate zone 5 (see ASHRAE 90.1, Table 3.1). No cooling was installed in the 1st floor. Unmet cooling hours are well over 300 hours. To fix this, the entire buildings energy performance drops drastically (proposed building is modeled with a Lobby cooling system as required per Table G3.1, 1.b in ASHRAE 90.1). Per the ventilation code (ASHRAE 62.1), a lobby is occupied and requires ventilation. Therefore we assume this must be input into the energy model. But I'm not convinced it makes sense to penalize the entire building for this transitional space designed to be enjoyed during the Winter months. Is it necessary to include the Atrium in the energy model per LEED?
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
April 13, 2015 - 5:21 pm
Yes you must model the entire building and it cannot be excluded.
If the space has no cooling system installed look at addendum dn. You can model it as a heating only space using a system 9 or 10 from 90.1-2010.
Joyce Kelly
Architect - Cx Provider - Building Performance SpecialistGLHN Architects & Engineers
27 thumbs up
April 13, 2015 - 6:19 pm
Thank you for your speedy reply, Marcus. Looks like that Addenda only applies to storage rooms, stairwells, vestibules (this Atrium is an awfully large vestibule), elec/mech rms & restrooms. The Atrium remains in the model and brings energy savings achieved down to 13%. Live & learn.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
April 13, 2015 - 6:28 pm
The LEED reviewers have allowed it to be used for other spaces. For example, it has been applied to heated only warehouses.
Another work around for spaces were you are forced to add a cooling system which does not exist is to set the cooling set points in those spaces so high that the cooling never comes on. This is kind of silly busy work so just tell the reviewer that rather than doing this you did not model the cooling system at all.
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
April 14, 2015 - 12:55 am
My two cents:
I would think about what part of the atrium needs to a) be conditioned to setpoint and b) requires the minimum oda rates. The occupied zone. And that for me means the first 2 m (6ft) of vertical height.
In e+ I would model an atrium zone as one zone using the 3-node-displacement air room model. This means I describe a temperature profile over 3 nodes, and place my air thermostat at a height of about 2 m. I define the height of my air inlets (typically jets at the bottom of the glazing, often in the floor build up) at a low level. The model now controls the zone temperature from the thermostat position and I don't have to be concerned about the entire space up to say 12 m high. This is both realistic and makes use of displacement ventilation to reduce costs. A "well mixed" zone model cannot achieve this.
I would do the same for the minimum ODA. I would make sure the breathing zone gets the minimum ODA, but I would be very carefull to consider ALL moisture loads. If you reduce the ODA too much you will get problems EVERYWHERE.