Hi there,
I've got a 24 floor office building to model. The floors have 4 different envelope designs and on each level of the building there are at least 7 different zones (after combining rooms with same usage and HVAC-System). Although the space use on every floor is almost the same it differs on at least 15-20% of its space by shifting (for example) the living room to different locations (with different orientations) on each level. Without simplifying the model I will have to model pretty much every floor seperatly resulting in an inconceivably complex energy model.
Since I'm new to model a building using the ASHRAE 90.1-2010 norm (appendix G) I'm not exactly sure what methods are allowed to shrink the model down to be usable. In my experience the arrangement of rooms on different levels of the building will only have a minor effect on the energy performance (if the space is kept the same). Which brings me to my question:
Is it possible to define standard floors to simulate which represent floors that are arranged pretty much alike but not exactly the same?
And another one: Which methods to simplify a model are allowed? If I'm not mistaken the ASHRAE does not provide a method to combine minor spaces with larger ones if they aren't pretty much the same. For example a small room (broom closet) of 10m² with a 260m² open office. For the overall energy consumption the small room is pretty much insignificant.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
September 21, 2018 - 11:12 am
What is the building type? Multi-family residential? Dorm? Something else?
The simple answer to you question is maybe. You are correct that it likely depends on the impact on energy use.
For more guidance on zoning and thermal block see Table G3.1-7, 8, and maybe 9 in Appendix G.
Hagen Bork
Projektleiter Nachhaltiges BauenCSD Ingenieure GmbH
2 thumbs up
September 24, 2018 - 3:32 am
It's an office building. ~80% of the space is used for open offices, group bureaus, meeting rooms, WCs, storing space and staircase/elevators.
In the first and second floor are areas for a lobby, a cantina and conference rooms. There also is a fitnesscenter in the building.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
September 24, 2018 - 10:47 am
OK I was thrown off by the living room example.
Technically this is not allowed. You must model the project as designed. However, if each floor has the same area then I think you could probably come up with some sort of typical layout and then just copy that for each "very similar" floor. The only major difference I can think of would be whether the project had a bunch of perimeter, enclosed offices that change orientation on different floors. This would assume that the energy use does not significantly change by modeling it this way. You could do a simple test by modeling two of the most different floor plans and see the difference in energy use. If it is very minor then you could provide this little study to the reviewer to justify using a typical layout. Or maybe you end up with two typical floor types. Hard to say without seeing the level of difference. Whatever you end up doing, if it deviates from the project design, you should provide a narrative justification to the reviewer explaining how what you are doing is thermodynamically very similar and would have a minor affect on energy use.
The lower levels sound more unique and would have to be modeled as designed.