In the situation that a design is utilizing an efficient exhaust/make up air
system, the LEED book says that an exceptional calculation may be used to
help quantify savings. This leads me to believe that the kitchen cooking
equipment is process, but the HVAC equipment is not. My office has been
having a "discussion" about whether HVAC equipment that conditions air for
process equipment is considered process as well.
Another example that is plaguing me: an electrical rack room has 90 kW of
stuff and requires 25 tons of cooling. If i use an efficient design, can i
take credit for it by comparing my design to a baseline of system 3 (PTAC w/
DX cooling and furnace heating)? I believe that this HVAC system should be
allowed to get credit, but others argue that because it serves process
equipment, then it is "process" heating/cooling.
Any thoughts from LEED AP out there? (i'm still working on getting my LEED
AP).
Thanks,
--
Rob Hudson
In my opinion...
Your HVAC system for the makeup air or servers / racks is HVAC for a room in
a building which (at least occasionally) has people in it. I think it
qualifies as non-process.
James V. Dirkes II, P.E., BEMP , LEED AP
My understanding is that your HVAC system is not process. Even in the old
LEED system where process energy/plug energy will be removed from final
energy cost savings, will still consider the heating and cooling energy
iccured by such process/plug loads.
Regards,
Cheney
HVAC energy consumption caused by process loads cannot be called process loads. Nor would you want it to be a process load, because then you can't take credit for savings or at least not as easily.
Correct, your electrical or IT room with 90kW baseline is a system 3, and your Proposed can be an efficient design. ASHRAE 90.1-2007 G3.1.1 exception b allows you to apply system 3 for zones with large process loads.
This can be a huge source of energy savings. Enjoy it now, because rumor has it that the next version of 90.1 will set an alternate baseline for IT rooms and the like, and system 3 will no longer be applicable because the energy savings can be ridiculously large.
Fred Betz PhD., LEED AP
I completely agree with you Fred. This is the same logic that i followed.
Unfortunately my superiors do not agree with this logic, even though I have
shown them the same exception that you mention. Their logic states that
process loads shall be the same in both models, and anything associated with
process loads (such as cooling for a data room or exhaust/make up air for a
kitchen) do not serve any purpose except for process and therefore is also
process.
Does anyone have anything from USGBC clarifying this issue? I have looked
through the interpretations and nothing speaks to the HVAC equipment of
process loads.
Thanks for the input so far,
Rob