Hello all,
There are two things that are confusing me right now:
1. I am trying to understand a comment that we recieved from GBCI regarding
the HVAC system that we used to model one of our projects. It is a existing
building with AHU's, Chillers, Electric Heat and FPB's with a square footage
of about 90000sf. I understand that the according to table G3.1.1B , the
HVAC system should be Type 6 and should have a direct expansion type cooling
and not a chiller for the baseline building. However, since the existing
building already has a chilled and the proposed would have a new more
efficient chiller, shouldnt i model the baseline with a chiller as well
since the existing building already has a chiller. Does anyone have
experience with this?
The renovation in the building is a major one.
2. Since the building is more than 5000sq ft , it has a mandatory
requirement of having occupancy sensors/motion sensors installed in the
baseline case. Now again, the existing building didnt have any motion or
occupancy sensors and did not have the LED lighting as in proposed building.
But since having the sensors is mandatory , do i not get any categpry for
having occupancy sensors? Also, if the occupancy sensors are to be modeled
should the percentage reduction in LPD to account for it in the simulation
from Table G3.2 be taken into consideration in Baseline as well as proposed
which would essentially mean that i would have no energy savings for
lighting?!!
Your help is highly appreciated.
--
Thanks
Sincerely,
Amit Bhansali, M.S. , EIT
Amit,
On your second question - as far as I remember (this is 2004 standard), the
mandatory occupancy sensors are on a space basis. So if you have occupancy
sensors in more spaces than what is mandatory, you can have the savings due
to them in these extra spaces. If the baseline does not have LED lighting,
then the proposed will have lower lighting wattage than baseline, giving you
lighting savings.
-Rohini
Rohini Brahme, Ph.D., LEED AP
I realize this has already been hashed out, but in searching the forums it sounded like they didn't get resolved so I am asking anyway:
The building we are designing has a very high process energy use (60%) because of a large data center and the TV Studio equipment, lighting, and broadcasting. The process loads stay the same in the building for the proposed and baseline case, so the difference in energy costs between the two (as a percentage) is very low. Whereas, if the data center energy, broadcasting energy, studio lighting energy weren't included in the costs for the energy usage in the building, the difference would be greater, thus reporting just the difference in energy usage for the mechanical system and building efficiencies.
Is there a way to not count the data center and broadcasting type equipment electrical loads for EAp2?
Previous listings mentioned that in LEED 2009 they were working on creating baselines of process loads for different types of buildings that you could compare your process loads to. Has that gone anywhere?
FYI: I am getting 3 points for EAc1 right now, but if I were able to magically delete the extra process loads above the required 25% from both the baseline and the proposed design, I would earn an additional 3 points.
Thanks,
-Jason
Jason,
There is no way to exclude process energy from EAp2/EAc1 calculations
under LEED 2009. The only way you can improve EAc1 performance is to
document process savings relative to some baseline. I'm also eagerly
awaiting some assistance from the USGBC/CaGBC/ASHRAE on baselines, but
I'm not aware that anything's been published yet.
In the case of data centre energy, I thought about using Energy Star
Portfolio Manager to determine a baseline by entering a portion of the
modelled building as a data centre (less than 10% of area), but I
suspect that Portfolio Manager, being a bit of a black box, won't spit
out a separate energy intensity for just the data centre space. I
think other modelers speaking on this issue have mentioned being lucky
enough to have clients with large data sets of previous projects that
they used for benchmarking various process loads.
It may seem unfortunate that, for the moment, high-process energy
buildings have a difficult time getting higher energy savings compared
to their low-process load counterparts, but if the goal is to reduce
building-related GHGs (as it should be), then it's probably about time
all energy use in buildings gets addressed. Not that good intentions
help modelers much for the time being without some baseline values we
can use.
Luka Matutinovic, B.A.Sc., LEED(r) AP
Hi Rohini,
i was addressing whats written in ASHRAE 90.1-2007 in section 9.4 for the
mandatory lighting standards. As i went through and had some inputs, what
appendix G really means is that we do not model the automatic lighting in
the baseline that makes the model with the maximum allowed LPD with a
schedule. However, in the proposed case the schedule remains the same but a
10% reduction on LPD could be done to account for the automatic lighting.
Now, my confusion is what Jorge said: "Your baseline for the renovation
portion of the work is in essence the existing conditions (envelope
components, equipment, layout, efficiencies, LPD, etc.)"
If that sentence were to be true than should i model the building with all
the pre-renovation values for envelope, LPD and consider that as the
baseline. Again, i have said this earlier that this is a major renovation,
and in the GBCI review, it has been clearly mentioned and i would
quote " Renovation
projects need to model the baseline case mechanical system following the
table G3.1.1A mapping as new construction projects" . The only point where
the existing values would hold good in a simulation would be on the envelope
side since in Appendix G #5 for Building Envelope, the (f) point
states that"for existing
building envelopes, the baseline should reflect existing conditions prior to
any revisions that are part of the scope of work being evaluated"
Please send me your suggestions and comments.
--
Thanks
Sincerely,
Amit Bhansali, M.S. , EIT