Lighting vs Energy Model

I'm just going to throw this out there; someone needs to own every analysis model and develop a method for keeping it current.
Working with Revit, my belief is that the Architect should own the daylighting model which can be exported either through room objects or BIM geometry. Room objects are the best candidate in that they often describe only those areas that need to be analyzed.
IES daylighting Image courtesy of RTKL











The energy model intended for thermal analysis is best created in Revit MEP using space objects. Space object can be placed into a linked Revit file in Revit MEP, but the must follow the room bounding rules set by the Revit architecture model. To get around this, spaces can be grouped together into zones for analysis, and a sliver tolerance can be adjusted so that leftover gaps don't require space definitions. We now just need to test how effective zones are and if there is an additional performance drain by having many small spaces which the energy modeller would not normally define (this will come in a separate post).

Added Later:

After some discussions I'm rethinking the concept that the Architect always owns the daylighting model. The architect needs to start a daylighting model to reveal problems while they can still be solved schematically. The big danger in Daylighting analysis, as described to me by Chris Chatto of ZGF Architects, is that the end result needs to be a value, either a 2% daylight factor or the 25 footcandle (269 lux) requirement for LEED EQ 8.1. In this case the analysis iterations are not intended to improve a design but to achieve levels above a defined value.



Without carefully defining all of the input parameters such as glass transparency, reflectance of materials, sky condition and others, one could seemingly prove that a design is adequate when in reality it is not.




This level of daylight understanding is not always present in every architecture office and so a level of collaboration becomes necessary. Who actually "owns" this model may end up an irrelevant question, but before deciding a model exchange strategy you have to know exact procedures and what to expect.




Ecotect to IES Exchange

I've mostly been using Ecotect as a design analysis tool, and since the engineers I work with are mostly using IES for lighting calculations I've had to find a clean way to exchange information between the BIM model, the design analysis and the engineering analysis tools (this process will come in a later post).