Sorry to post a LEED-related question, but I thought someone might have run into this in the past for EAp2 modeling using the developer control alternative compliance path calculator.
I posted this same question on LEEDUSER but thought I'd get more responses from the modeling community here!
I've done a number of Core and Shell models before, and always use the ACP calculator. However, something that I've noticed before but never understood is why the Revised Point threshold column is a single column and NOT separate revised thresholds for New and Existing. As an example: In a current project, I have a developer control percentage of 47%. It says that any savings over 13.8% gets you 6 pts (see chart below). This is a nice drop from the 18% required for a non-ACP path to get 6 pts for new construction projects. However, the non-ACP path for 6pts requires a renovation project to have 14%. In other words, the ACP only lowers the 6 pt threshold from 14% to 13.8% for renovations. Why does this happen? Is it just something you have to live with for renovations? Or is there a way you can pro-rate this to be valid for existing building renovations? Thanks!
Enter the Percent of Energy Cost Influenced or Directly Controlled by CS Owner/Developer:
47.0%
Standard Compliance Path
Savings as a Percent of Core & Shell Building Load
Alternative Compliance Path - Revised Point thresholds based on Percent of Energy Cost influenced by Developer and Percent New Construction versus Major Renovation
Points
New
Renovation
Prereq
10.0%
5.0%
6.3%
3
12.0%
8.0%
10.0%
4
14.0%
10.0%
11.3%
5
16.0%
12.0%
12.5%
6
18.0%
14.0%
13.8%
7
20.0%
16.0%
15.0%
8
22.0%
18.0%
16.3%
9
24.0%
20.0%
17.5%
10
26.0%
22.0%
18.8%
11
28.0%
24.0%
20.1%
12
30.0%
26.0%
21.3%
13
32.0%
28.0%
22.6%
14
34.0%
30.0%
23.8%
15
36.0%
32.0%
25.1%
16
38.0%
34.0%
26.3%
17
40.0%
36.0%
27.6%
18
42.0%
38.0%
28.8%
19
44.0%
40.0%
30.1%
20
46.0%
42.0%
31.3%
21
48.0%
44.0%
32.6%
GHT Limited
James Hansen, PE, LEED AP, BEMP
Principal
1110 N. Glebe Road, Suite 300
Arlington, VA 22201
703.338.5754 (direct/cell)
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Hi James,
I've executed (and also deliberately avoided for strategic reasons) this
ACP a few times over for CS projects under LEED v3.
I think you know this, but it may bear repeating for newer subscribers.
Historically, LEED-specific queries & discussions have been quite
popular/welcome here at onebuilding, and in this forum particularly
[bldg-sim]! I understand GBCI does keep a watchful eye out for related
discussions here (and will occasionally take direct actions in
response), but they do not as a general rule actively participate. I
reckon this is primarily due to their focus/ties around the LEED user
forum, as a means of consolidating what's "official." In any case, I
think you're going to reach a unique spread of expertise here with "in
the trenches" experience/perspectives covering various simulation
platforms, so please don't feel averse to cross-posting. That said,
treat all of the following as "end-user" advice (not necessarily
endorsed by those calling the shots).
I could be wrong, but I think there's some simple logic at play here
that lends credence to a single ACP threshold column, based on the "new"
thresholds:
All else being equal: When you are doing a CS renovation project (as
compared with new construction, in LEED terms), you have a couple "soft"
advantages for determining the "directly controlled" percentage, which
may explain why there isn't a separate sliding scale:
1. Relative to NC, you have an added potential for more
"know-able" tenant-controlled loads in an existing, occupied/tenanted
facility that can be definable/claimed in determining your "owner
influence-able" percentage. This in my experience requires some extra
legwork to at minimum seek out tenant construction docs through the
developer. Eyes on the ground (with a camera & notepad) may be a
worthwhile venture in some cases to help document & find the variety of
loads that are truly outside the developers control.
2. Relative to NC, & depending upon renovation scope, you may be
able to draw a tighter line with regard "directly controllable" loads
(due to project boundary or budget/scope), and in turn document a lower
percentage of "directly controlled energy cost" by accounting for
existing "core" loads your project can't touch. For example, if your
project involves upgrading/replacing core HVAC, you definitely cannot
claim those energies as outside the "controllable" sum, but if the
budget/scope will not allow for replacing the existing
escalators/elevators, you may be able to include those. In another
sense, your renovation project may be adding square footage within the
50% threshold, thereby not triggering the "NC" flag for LEED, but again
leaving other existing loads typically considered "Core" outside of the
touchable scope (spatial project boundary).
If GBCI were to someday refute/shoot-down the above points in an
official capacity, then I'd totally agree the burden would be on them to
come up with a separate "ACP-adjusted" scale for renovation projects.
Also some related general tips: When opting to leverage the ACP (it
doesn't always fit for every CS project), be sure you're seeking out and
accounting for any of the following that may apply:
- Tenant Lighting
- Tenant plug loads
o Be careful to document "Actual" plug loads if simultaneously
pursuing reduced plug loads via exceptional calculation.
o Consider pursuing documenting "Actual" plug loads even if not trying
to claim exceptional savings, if a known tenant would clearly exceed
typical W/ft2 entries (i.e. a Kinko's print shop or a tanning salon is
involved).
- Other Tenant process loads
o Tenant IT/data room server equipment
o Cafeterias/Kitchens within the development/building are commonly a
"gold mine" under the ACP
o Tenant-specific security head-end equipment can occasionally be
substantial enough to seek out and include as well.
- Tenant process-related supplemental space conditioning (where
not delivered by the developer). There's a fine line to walk here (one
of the examples in the ACP Instructions tab speaks to tenant HVAC in a
general/broad case), but I think it's very appropriate/fair in some
cases to account for specific tenant HVAC loads which are totally
outside the influence of a CS owner/developer. Examples that come to
mind may include walk-in freezers for kitchens & supplemental cooling
systems for tenant-process-heavy spaces (like printer/server rooms). No
amount of developer envelope/HVAC influence will prevent tenants who
need such extra conditioning (at whatever efficiency) from putting those
loads on the meter.
~Nick
------------------------------------------------------------------------
------------------------------------------------------
Nick Caton, P.E.
Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric
D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com
F 913.564.6380
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States
Thanks so much for the response, Nick! I should have provided a little bit more info, and told you that this is for a speculative office building, with no known tenants. In other words, on Day 1 when construction is complete, this building will look just like a new construction project, except the floor slabs / some fa?ade / roof will remain. That's why I was thinking it was unfair to penalize an existing building via the ACP path. Penalize probably isn't the right word, rather "lessen" the positive impact the ACP has for existing / renovation projects.
I have always told owners that there is no benefit (in terms of EAc1 points) to restricting tenant lighting for a core and shell project, because as soon as you do that, the lighting energy end use group has to go into the "developer control" side of the equation, and you end up almost eliminating the positive impact of the ACP (you might have gained a point or two by restricting tenant light power to 75% of 90.1 allowances, but the ACP gets you 4 additional points if you don't do this so why bother).
But now, with an existing / renovation project, because the ACP doesn't substantially improve the point thresholds, it almost IS worth restricting tenant lighting when talking about EAc1 points. It just seems that there shouldn't be a difference in guidance on this sort of thing from a new core and shell project versus an existing / renovation core and shell project, you know?
Thanks again!
-James
I'm with ya!
For you current project's scope (for additional perspective & to accurately convey whether/why you're pursing ACP), you might want to double check whether the scope you're describing wouldn't fall under the "New" column, regardless. I might be wrong, but I thought it hinged on the ">50% of gross building area is getting messed with" (my words) threshold?
It took me a few projects to realize this, but whether you are pursuing the ACP path has influence on many little decisions (like LPD restrictions & whether you want to invest extra time identifying, documenting, and including tenant process loads in your simulation) in the course of model development. This also influences what I would advise a design team / owner along the way for related points. For this reason alone, I've shifted to exploring the ACP "impact" potential towards the earliest stages of LEED model development (pretty much as soon as I can get a first early look at baseline vs. proposed performance). I ask questions along the lines of "what is known or will be know-able/document-able with respect to future tenancy" and "will our client be willing to contractually mandate things like maximum LPD with their future tenants (which may impact how quickly the shell building is occupied) if it would means approximately (rough estimate) more LEED points" (I have found cases where such savings specifically do work out in favor, big-picture).
These sorts of exploratory queries of course require a substantial amount of "from the hip" estimations at the time you want to get them answered, but model development for CS jobs can be a much more streamlined path when you can assert for yourself that ACP is going to be good fit (or not) for the project/client.
~Nick
------------------------------------------------------------------------------------------------------------------------------
Nick Caton, P.E.
Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric
D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com
F 913.564.6380
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States
(I see we're crossing between lists now, so CC'ing both in case some are
following on both sides)
To reinforce context, I was referenced kitchens as "gold mines" when
considering the alternative compliance path (ACP) for LEED core & shell
(CS) projects.
Generally (when not using the ACP), energy simulators leveraging
Appendix G for various flavors of LEED observe the trend that process
loads commonly function as "dead weight" with respect to demonstrating
energy performance. This is because (short of exceptional calculations)
the baseline must match the proposed case for all process loads. In
turn, higher percentages of process loads = lower % of loads with which
a savings can be demonstrated.
This leads to a general point-of-fact strategy for LEED simulation
development, for those with a goal to maximize earned LEED points: You
want to document only as many process loads as are minimally
mandated/required, UNLESS you can document via exceptional calculation
that the proposed case should be lesser than the baseline case.
The ACP however institutes a few rules which add some nuance to this
general position, and for some cases flip the picture around.
Under the ACP, one may distinguish "tenant-controlled" energy
consumptions which the building owner/developer has zero control over.
Typical examples provided in the ACP documentation include tenant plug
loads, tenant lighting, etc. Those loads get sub-metered in your
simulation to determine a "tenant-controlled" energy consumption total.
That sum is compared with the total building energy consumption to
determine a "developer controlled percentage" of energy. That percentage
(if sufficiently small) can be applied using the LEED ACP spreadsheet to
determine a favorably adjusted set of performance rating LEED credit
thresholds. Altogether, buildings with more loads out of the
owner/developer's hands can achieve the same # of LEED points after
demonstrating a smaller performance rating (%), because they have more
"dead weight" to carry. Fair concept.
Put another way: under the ACP, you are "rewarded" for identifying,
documenting, and simulating a larger amount of tenant-controlled loads.
This has some very interesting trickle-down effects on how an energy
modeler should influence/advise their clients (designers/building
owners). It also effects how one approaches/documents process & other
tenant loads during model development, and creates some new incentives
to seek out additional documentation which you might not otherwise
pursue.
Explaining my reference to kitchens as having "gold mine" potential in
this context: I have observed for a number of LEED-CS projects which
had cafeterias or restaurants programmed in the core/shell building
documentation, that the actual kitchen equipment package was
demonstrably outside the control of the owner/developer (either handled
by a planned building tenant or another 3rd party independent of the
building owner, commercially responsible for kitchen operations). In
turn, the full sum of kitchen process loads could be classified as
"tenant controlled" and are actually BENEFICIAL under the ACP
(measurably lowering the thresholds for additional LEED points), but
HARMFUL outside the ACP, unless you go the route of exceptional
calculations (documenting "standard" vs. "selected" cooking equipment
efficiencies).
Here is where Chris's query lands - dealing with kitchens equipment
packages via exceptional calculation, outside of ACP.
Kitchen equipment packages are never a small amount of extra effort to
document, but the effort can potentially be worthwhile if
1. Kitchen loads are ultimately going to be a substantial chunk of
the energy consumption pie and
2. The right people are involved. In my experience, this working
out very much depends on the technical competence and willingness of
your kitchen equipment package supplier to invest the extra time needed
to source/dig up some of these specifications.
There was once a "3rd party" spreadsheet available on the fishnick
website which (to my experience) first made documentation of baseline
kitchen equipment loads an approachable endeavor. Over time the effort
of maintaining/expanding that resource has migrated into usgbc website.
I have this link in my bookmarks, though I should voice it looks very
different from the last time I peeked here:
http://www.usgbc.org/node/4335155?return=/credits
I'm not aware whether (a) there remains any "official" spreadsheet
collecting this information for easier manipulation/coordination, or (b)
whether there is a separate USGBC/GBCI source for LEED v3 baseline
kitchen equipment requirements.
~Nick
Nick Caton, P.E.
Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric
D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com
F 913.564.6380
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States