Hey all,
I'm going to throw this out for general comment. If it has been hashed before, please forgive me. I have been exploring the Heating/Cooling loads of Revit MEP. While I understand, perhaps 4% of what the output is, I know there is some concern over it in general. The biggest problem I see is that we are letting Revit calculate our HVAC loads based on the Architectural Model. So, in effect, we are trusting putting our seal attesting that the loads that we calculated (or that Revit calculated) is partly based upon what the Architect chose for their wall types, slabs, and roofs. That makes me nervous.
We also use Trace 700 for calcs, but at least there WE have control over the inputs there. Having said all of this, I know that best practices dicatate that we back any calculations up on paper and use that as our basis. But I wonder how many people actually do that? After all time is money, and if time is spend to recheck something that a program is meant to perform, then that *could* be construed as time "wasted". I know some engineers that base their design totally from computer-generated design/calculations but then throw some "magic" safety factor in and "all is well".
Just last summer (and actually this week), the USA has seen some pretty wild temperature swings that throw the ASHRAE weather data right out the door. Luckily, with the safety factor (and ability to modify the weather in Revit), we can try to cope with those changes. But is there a place to override what the architect has chosen for their Exterior walls, Slabs, Exterior windows, and roofs to allow for us, the Mechanical guys more "peace of mind" for the proper U-valves? I'll be honest, I haven't looked too deep into it, but if someone who has more extensive experience could chime in, that would be great.
Are there published best practices for using Revit MEP Heating/Cooling Loads Calcs? I have checked out all the Autodesk videos (which are pretty much "press this button", "oooohhhh magic"). So, I'm trying to gather information for my boss on this, as far as reliability. Do *you* trust the output? Any and all comments are appreciated.
Rick
