Given our unique project conditions we are pursuing this credit via Case 2, Option 2B. This option allows for normalization of historical energy data for things such as, changes to occupancy, operating schedules, space use, etc.
How do we derive the multipliers that should be used for normalizing our data? One reviewer we spoke to indicated that an energy model was not needed and the calculations could be done much more simplistically. Can we use linear relationships such as twice the number of occupants equates to an assumed 2x energy usage? Or, there was an addition to the building, so would a 20% increase in conditioned space volume equate to an assumed 20% increase in energy usage? And what about less quantifiable aspects like space type changes?
Does anyone have experience with this? Any tips or resources for this endeavor is greatly appreciated! We are trying to get this turned around quickly.
Michael Opitz
Director of SustainabilityIconergy
60 thumbs up
June 20, 2013 - 9:28 pm
Timothy:
I agree that an energy model would be overkill in this situation. In general, yes you can use linear relationships to adjust the EUI of your existing building, because under the hood ENERGY STAR itself also uses linear relationships to generate scores for ratable buildings, and EBOM relies on ENERGY STAR as much as it can.
But you must still use good judgment when adjusting your EUI. A 20% increase in floor area would generally lead to a 20% increase in energy use, but only if the new addition was of a similar usage type as the original space. For space type changes, you should compare typical EUIs of the old and new usage types from CBECS data, as they usually are quite different. And scaling for the # of occupants is complicated - it depends on whether the extra people are in new, dedicated floor space, filling pre-existing but un-leased (and thus unoccupied) floor space, etc.
Good luck.