Energy Model Cost

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Greetings everyone,

I have a question regarding the cost of an energy model for a LEED project.
Every energy model I've done so far has been for

existing buildings, mainly for optimization purposes. However, I received an
RFP to model a five-story, 41,500 sq. ft. building

that's currently on the design phase and is pursuing the LEED-NC Silver
certification. I really have no idea what would be a fair

price for this model since I'm going to have to use Appendix G (ASHRAE 90.1)
to evaluate the difference between the base

and proposed buildings. I don't know how much extra effort this will take. I
know the procedure, just haven't done it before.

Can you shed any light on this issue?

Thanks in advance!

Omar A. Delgado Col?n, P.E., MEnvM., LEED AP BD&C

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Omar,

I would expect, for a building this size, approximately 40 hours (multiply by your hourly rate). The 40 hours include EAp2/EAc1 LEED documentation, and any review you may have to respond to later.

Now, given that you have never done a LEED model, it will take you more time, possibly up to 40 more hours.

HTH,

_______________
Demba NDIAYE

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Omar,

I agree with this assessment. I usually consider up to two weeks of work for a skilled modeler to complete the simulation and documentation, assuming all the relevant information is readily available, and that you won't have to correct/update the model as the project goes.

Though it depends more on the project complexity, re: envelope and HVAC systems, and less on project size. A cubic building with 20 times the same HVAC system is simpler to model than a multi-wing building with variable fenestration ratios and 20 different HVAC systems.

Regards,

Fr?d?ric Genest

De : Demba Ndiaye [mailto:Demba.Ndiaye at setty.com]
Envoy? : 12 mai 2011 16:28
? : Omar Delgado; bldg-sim at lists.onebuilding.org
Objet : Re: [Bldg-sim] Energy Model Cost

Omar,

I would expect, for a building this size, approximately 40 hours (multiply by your hourly rate). The 40 hours include EAp2/EAc1 LEED documentation, and any review you may have to respond to later.

Now, given that you have never done a LEED model, it will take you more time, possibly up to 40 more hours.

HTH,

Demba NDIAYE

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Let me know when you ever work on a project where all relevant information is readily available and you don't have to correct/update the model as the project goes. J

William Mak

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Omar,
I would recommend that you add some additional time to respond to GBCI comments after submitting the EAc1 documentation, too. Often they will ask for changes to the model and a written narrative to answer their concerns. You may want to budget several days to do this (or list it as an hourly service) if this project is complex.

Best,

--
Shanta Tucker

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Dear Omar,

My opinion is that you?ve done the harder project already ? an existing
building!

For a LEED certification you often have more freedom in certain areas, such
as occupancy and equipment schedules because all schedules do not need to be
precise ? they?re just someone?s best estimate. In an existing building
model, you must get fairly precise so that your model matches the utility
bills.

For LEED, you have:

? One geometry description (length, width, height, windows)

? One set of schedules for occupancy and diversity

? One set of information about ?process? equipment

? 2 sets of materials (Walls, Roof, windows for Baseline per 90.1
and actual)

? 2 sets of HVAC equipment (Baseline and actual)

o Carefully consider zoning before you begin and review the requirements
for Baseline systems in 90.1. You may have more than one system type,
especially if some areas of the building have significantly different
schedules or other criteria.

? 2 reports (generally ?ABUPS? is needed for each model) which
describe the key differences between the systems and their performance

o Including performance in sub-categories such as ?lights?, ?cooling?,
?heating? as described in the LEED documentation

? 1 comparison of the 2 systems which results in an overall
operating cost comparison.

? Some time with LEED online to load all of your reports

? Possible time to discuss and explain results with the LEED
reviewer

I normally exclude from my scope the documentation of all of the mandatory
requirements in Sections 5-10 of 90.1. These are normally much easier to
document if you are the designer, since the information is readily at hand
and, presumably, you have incorporated them purposefully during the design
process. I also state that we do NOT guarantee any LEED points whatsoever;
that?s the designer?s option. The modeler is only documenting estimated
performance what has been designed, not guaranteeing its performance.
Finally, we also state that the performance is estimated, not necessarily
even close to what will actually occur. I show some typical language below.

As you can see, I?m not saying ?40 hours?. Rather, compare what you know
about the cost for an existing building to the items which are different in
a LEED certification for a new building, make an estimate using that
information. I hope that is helpful!

1. Energy models are not intended or expected to match closely with
actual energy use. They ARE expected to provide a reasonable basis from
which to judge overall patterns and enable comparison of design options.
New buildings, especially, represent challenges which are not precisely
quantifiable by an energy model. These include:

? Patterns of occupancy and lighting use are not established

? Equipment, including office PCs and copiers, has not been
installed and it is not known how much power will be used nor how often.

? Weather patterns vary from year to year, while the energy model
uses a ?typical? weather pattern.

? Equipment efficiencies, control sequences and controls calibration
normally vary from planned, design information.

James V. Dirkes II, P.E., LEED AP, BEMP

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Well, I can dream, right? ;-)

Frankly, I was hinting that you ought to wait "until the end" to model for LEED... J

Regards,

Fr?d?ric Genest

De : Will Mak [mailto:wmak at epsteinglobal.com]
Envoy? : 12 mai 2011 16:46
? : Genest, Frederic; Omar Delgado; bldg-sim at lists.onebuilding.org
Objet : RE: [Bldg-sim] Energy Model Cost

Let me know when you ever work on a project where all relevant information is readily available and you don't have to correct/update the model as the project goes. J

William Mak

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Dear Omar,

If you are providing both energy modeling and functioning as building
performance advisor providing design assistance, be sure to factor in effort
for each project phase.

*Schematic Design*
Sketch Models to evaluate form, massing, orientation, architectural
alternates. Here you are either comparing a simplified baseline to
simplified proposed designs, or you are comparing multiple proposed designs
with each other. Be clear on the metric of performance per project goals.
Energy use or cost or carbon, etc. This will depend on whether energy is
purchased or generated on site.

*Design Development*
Your first round of Performance Rating Method models, one baseline and one
proposed model. Some design decisions will have been made by the design team
but a number of assumptions will still need to be made. The purpose of this
round of modeling is to benchmark the project against project LEED targets,
e.g. "are we still good for Silver, or are we down to Certified".

*LEED Model*
In an ideal situation you are able to salvage your Design Development phase
efforts, but the reality of projects may require you to bring your model
back into wizard mode, reconfigure zoning and window placement, and then
either patch in systems from a previous model through text file, or if the
system design has evolved significantly, you may need to build from scratch.

When all is said and done in this type of consultancy, you are building 4+
models, including working models, all to differing levels of detail.

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In our experience a final model, done right, would take about 80 hours.

WARNING ? frustrated modeling rant to follow:

Doing just a final model however completely misses the point as to why we
model ? it is to guide design decisions!

If I saw this RFP and all it asked me for was a model to determine LEED
points, during or after design, I would try to educate the potential client
about the purpose of modeling.

Unfortunately too many projects pursuing LEED are only doing the minimum
when it comes to modeling and almost completely missing all the benefits.
Too often the ?market? transforms only based on a least first cost
denominator basis that results in little real transformation. Doing models
to determine LEED points does not transform the market, save any energy, and
just circumvents the purpose behind LEED. (the next version actually
requires design phase modeling!)

Any ?modeler? who does only final models without attempting to explain to
the owner why this is a bad idea should be ?drummed out of the corp? in my
humble opinion.

The problem is that if you respond to this RFP with 120 or 160 or more hours
to really do the design phase modeling right, you will go up against the
?modeler? who claims to be able to do it in far less time. So how do we get
the folks who issue the RFPs to ask for a proper scope of work so that they
can compare fees on a level playing field? It is unfortunate that we are
even having a discussion about doing modeling work in opposition to its
purpose.

Sorry for the rant but I feel better now. J

Marcus Sheffer

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Hi all,
I also agree with the 2 weeks and if in the
building is in Canada it is easyer to use EE4 as
you get the MNECB base line and in the US Equest
can give you a title 24 that is accepted as 90.1 baseline

Martin
J

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Marcus,

You have inadvertently hit upon why IBPSA worked with ASHRAE to create a
BEMP certification. That's Building Energy Modeling Professional (BEMP).

Some of us who have been in the field for awhile began to worry a couple of
years ago when so many new energy modelers began appearing on the listserv
with questions. Their questions indicated a lack of training and experience
that was worrisome. What made it worrisome was that they didn't seem to
realize that they were as inexperienced as they were; they didn't appear to
be pursuing training to learn how to do what they were doing; and we were
uncertain as to how or if they were practicing quality control. We hoped
that by creating a path to certification that we would give clients one more
qualification to look for in their modelers.

If you have been in this industry for any length of time, and by industry I
mean the overall construction industry, you know that you don't get a lot of
chances if your work doesn't pan out. If your energy model says I have a
LEED Gold building and I'm going to save $4,000/year and what I really get
is LEED Silver and $1,000/year, I am not going to be happy. So, I will
probably not give you any more work but, even worse for all of us, I'll
start expressing doubts about the whole process. LEED - what is it good for?

So, now we all have more training, right? We read our ASHRAE Handbooks and
technical manuals so we know how to model the difficult stuff. We can find
any topic in the DOE2 Manuals, all of which are one line, available, and
easily searchable.

So now we are so good we can do these models in 40-80 hours. Really? Not me
and I've been doing it longer than everyone, except you, John Aulbach. So
I'm going to join Marcus in his rant because he's on to something.

It's up to us to not under bid this work. It's up to us to educate our
clients about the importance of quality in this process. If they think they
are getting the same analysis in 40 hours that they used to get in 120
hours, they need to be led around to rethinking that and to be reminded that
GIGO.

Cheers,

Carol Gardner PE

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OK, Carol..now you threw the "bait" out there..older than dirt, eh?

I have done very limited LEED "type" modeling where you compare 20 walls and 40
windows types (well, it seemed that way).?Correct me if I am wrong, but a Base
model must be built to comply with a certain level of ASHRAE 90.1 (now up to
2010 ??). With all of the nuisances of eQuest 3.64, I am going to build the
model from scrathc and put in all the relevant baseline data in by hand.? And,
by the way, the ASHRAE baseline model might be an entirely different system.? I
am just completing an EPACT evaluation (ASHRAE 90.1-2001) and the Baseline HVAC
was screwe chillers, whereas the Actual building was packaged units with
Turbocor compressors (ask me how?I did that).

It very much depends on the complexity of the building. A 40,000 sf office or a
500,000 sf hotel with casino facilites.

I am unfamiliar with the LEED paperwork to be filled out after the modeling has
been done. But I would not do anything of this type in under 120 hours,
preferably 160 hours. If the client thinks he can do better, let him.

Contingency, contingency.

We won't discuss how old CAROL might be..

John A.

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Hi, everyone,

In my experience, 160 hours working time is only for design submission, for
a mid-complex building.

There are something maybe happen which cost a lot of time:

1. Most of time the client and also MEP partners will compare the
building loads between energy model and MEP partners calculation. The
modeler need to find the calculation difference, and figure out why this
would happen and how to fix.
2. Architect and MEP partners will ask the modeler to do parametric
studies to compare options. The modeler need to run the model - sometimes
there will be some issues which also need time to solve.
3. Client wants to know the effect of each energy saving strategy. The
modeler need to do a lot of runs to make clear about this. And also there
will be some problems happen, modeler need time to solve it.

After received the comments from USGBC, it depends on how many comments you
get. Normally 40 hours around to answer those questions if the model has no
big mistake or missing.

In the end there should be some extra hour for safety which depends on the
complex of the project.

Best Regards,

Grammy, Jiang

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Interesting discussion! I'll avoid the vintage debate... if you guys are a finely-aged bottle of wine, that just makes me grape juice =)!

"Good" energy models can encompass a range of accuracies/expectations...

1. On one hand, some clients require the models match "reality." This desire sometimes needs to be tempered with the unknowns of new construction & future performance, but given enough historical data a well-calibrated model is certainly approachable. "Calibrated modeling" has nothing to do with LEED-NC.

2. On the other hand, forward-thinking design team members will approach me to isolate specific measures and compare their impacts in a relative fashion to make informed energy-conscious design decisions. In this case, nobody cares whether the rest of the model is anything other than a "from the hip" estimate, but it's up to the modeler to determine what variables deserve extra attention for their effects on determining the outcome. A "good" model in this context delivers quick answers which are accurate in a relative sense, isolating the correct variables. "Preliminary modeling" is a very distinct skillset, is often based on little "real" data, and requires a different mindset to indentify all the variables in play so as to isolate what's not critical to the study at hand.

3. Somewhere in between these extremes lies the realm of "LEED models." LEED-NC models can be characterized as 'prescriptive guesswork.' They are based on design decisions made (but NOT reality). EPAcT and code-compliance modeling are similar in this regard.

Each mode of modeling requires different time investments, each has marketable value, and one can be an expert in one mode of modeling while being inexperienced in another.

If I were asked: Is it feasible to construct a model that will survive the rigors of a LEED review and earn a lot of points in 80 working hours? The answer is yes, it's definitely feasible. The actual number depends heavily on the complexities of the proposed design as others have explained well enough, but for a simple enough project, 1 to 2 working weeks could easily be more than enough. I'd reinforce the earlier points to add a fluff factors if you're unfamiliar with the process or systems involved.

That said: A "good" LEED model is in my definition simply one that earns a lot of points after review/approval. A good design helps "good" LEED models happen, but the reverse isn't true.

A "good" model in the context of "accuracy nearing reality" implies a much higher caliber modeler and an extended timeframe.

I take a firm stance that LEED/90.1 are not a means of enforcing "reality" upon a model. To rephrase/reinforce: a LEED model is not a "real" model. The sole function/purpose of a LEED model is to earn LEED points. Now, that's not to say a LEED model during its creation is not of some use to the design team, but such models are frankly most efficiently put together after the design process is well under way/finished.

The intent of EAc1, in my opinion, dances between two commendable goals:

1. Design buildings that use less energy

2. Get an energy modeler on the team to inform the design, helping to achieve goal #1

Problem is, 90.1 Appendix G is not a guideline/standard for how to inform design. EAc1/EAp2/90.1 as currently constructed is a metric for assessing the performance of the final design, after the critical decisions are made. That's why "LEED models" are best built after design is (mostly) complete, and that's why "LEED models" make for a flawed approach to guiding early design. In the course of a LEED project, I am always a part of the design team (typically directly involved in electrical/mechanical design), and will often construct "preliminary" models along the way to guide the process where questions come up across disciplines. These models bear little resemblance to a final LEED model, but help the design move in a direction that actually saves energy. This is very different from the documenting performance against an arbitrary baseline. As a result of this early involvement, getting lots of EAc1 points later is a simple matter of correctly modeling the actual design, not "finding points."

I can't offer much regarding hourly estimates to the independent consultants out there... Rather than charging an hourly rate for modeling services rendered, I am typically embedded in the design team, and said efforts are rolled into "design hours." Modeling generally isn't billed separately, but rather treated as value added to our design services. Hours spent on modeling is not the critical figure here, though it can be extensive in scope - what's important is the repeat business we get from very satisfied clients, both inside and outside of LEED.

Hope some of that helps! It's mostly my current perspective - I reserve the right to change my mind =).

NICK CATON, E.I.T.

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If anyone has any good ideas about how to structure the LEED credits to end the practice of validation models at the end and encourage/require design phase modeling the folks on the USGBC EA TAG would love to hear them. The current proposed credit language from the first public comment phase is listed below.

NC, CS, SCHOOLS, RETAIL, WAREHOUSE & DISTRIBUTION CENTERS, HOSPITALITY

Establish an energy performance target no later than the schematic design phase. The target must be established as kBTU per square foot-year of source energy use. This target must be mapped on the same scale as the baseline and proposed buildings, if the project follows Option 1.

OPTION 1. Whole Building Energy Simulation

Analyze a minimum of at least nine efficiency measures during the design process and account for the results in design decision-making. Analysis can include energy simulation of efficiency opportunities, application of past energy simulation analyses for similar projects to the project, or application of published data from energy analyses performed for similar projects to the project (such as AEDGs).

A minimum of six energy efficiency measures focused on load reduction strategies appropriate for the facility must be analyzed. This analysis must be performed during the schematic design phase.

A minimum of three energy efficiency measures focused on HVAC related strategies must be analyzed (passive measures are acceptable). This analysis must be performed before the conclusion of the design development phase.

The results of the analysis must be summarized in a brief report or memorandum.

The next version of LEED will be going out for public comment again in July, I think, so please comment formally as well as discussing here.

Marcus Sheffer

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SOOOO ON TARGET!!!! Unfortunatley in NY, NYSERDA exacerbates the issue because they get owners to use their TA's for modeling and just cover the cost of the final (and the owner's aren't knowledgable enough to understand what they are getting) completely defeating the real benefit of the model; an iterative process to guide the design.

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Energy Modeling Accuracy: It depends on the required level of accuracy. It can be done in one hours or even less, and could take two months with extensive calibrating and preferably field data monitoring for calibration. Same thing with the experience of the modeler: It might not require any experience at all or a modeler must be expert in mechanical system, heat transfer, moisture transfer, lighting deign, etc, and specializations in certain parts of energy modeling. Since LEED does not have staff to check or verify the level of modeling accuracy, I think LEED requires modeling just to satisfy getting points.

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Marcus, thank you incorporating this language.

The one scenario we often see in our design guidance work is that a
proposed design when compared with other design alternates does not
necessarily provided the largest energy savings when compared against
its own baseline case model. It is difficult to make a recommendation
as consultants when we want to present the Owner with both real energy
cost savings without compromising their LEED certification level
targets.

A recent paper presented by the Weidt Group at SimBuild touched on
this issue:

http://www.ibpsa.us/pub/simbuild2010/technicalPresentations/SB10-PPT-TS02A-03-Baker.pdf

Arpan Bakshi, LEED AP BD+C

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Do you know where we can get a copy of the existing draft? I?d like to look more into the new wordage for EAp2/EAc1 and how energy modeling will have to evolve once that new rating system is released.

William Mak

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GBCI does have technical staff and consultants who do verify modeling accuracy for LEED projects, to a degree. While they do not have the time to check the modeling file itself, they do review inputs and results for accuracy. They also enforce the Appendix G protocol which ensures uniformity, also to a degree.

If you do the minimum, then yes, LEED only requires modeling to determine points. Personally I am not satisfied with doing the minimum for any client and don?t like to work for clients who only want a plaque. This is not an indictment of LEED itself but of the way that this tool is used in the market. See my previous post about providing ideas for making modeling more effectively used on LEED projects. How can LEED do better?

Marcus Sheffer

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Carol, to add to the comment about modeling certifications, lets not
forget you can only manage that which can be measured!

There are two parts to this which we are missing before we can rest
easy about our models accurately reflecting the mechanical design!

The first is the creation of a modeling handbook in addition to the
ASHRAE handbooks providing documented modeling methodologies. Until we
have this in place, even two experienced and 'certified' modelers will
yield different simulation results when different modeling methods are
used for the same systems.

The second item is the accuracy of the modeling tool. How can a model
be accurately reflecting a mechanical design when any of the systems
designed does not having corresponding mathematical software models
and the model is a quilt of 'thermodynamical equivalents'? Unless your
work consists of standard air distribution systems, or you are using
EnergyPlus or TRNSYS, the majority of models created for LEED
certification in DOE2 are still comparitive approximations at best,
and just wrong at worst! I personally feel if we all had to purchase
annual subscriptions to eQUEST, maybe our friends in California would
be able to dedicate more resources to aid their development efforts_

Arpan Bakshi, LEED AP BD+C

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Could any one advice why LEED would not put the base design as Watt per square foot, or per occupant, or per hotel bed etc. so the Architecture becomes more innovative early in the design to save energy?

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Omar,
This is cracking me up. I don't think I've ever seen this much traffic on one
issue! LOL.
Regarding the manhours for a LEED model - my opinion is that the amount of time
has much more to do with the level of certification the project is going for, at
what point the modeling services are engaged in the design, and the type and
complexity of the building (systems). That's not to say the number of manhours
is completely independent of building size (square footage), but its not
particularly sensitive to it. I find that that there is a high "low" and low
"high" for modeling. In other words, it's hard to complete an energy model in
less than 60-80 hours (all said and done - paperwork, LEED responses etc), but
it rarely take more than 250 hours. (Although, some rare complex projects going
for platinmum could take up to 350 hours). Like others, I find the norm for a
reasonably complex bldg going for LEED silver or gold typically requires between
120 and 160 hours.

Marcus
Here's my two cents on below. I will look for the public comment period as
well. Thanks for the heads up.
I think the idea of incentivizing modeling early in the design is a great idea,
but I think requiring it is completely inappropriate. Perhaps it could be
encouraged by awarding an extra (innovation? or EA cr 1?) point for starting
modeling in schematic design. Or, perhaps the credit could be restructured
similar to the CX credits where in order to get the enhanced CX credits, you
have to have the CX agent involved early in the design. In some ways, the
current set up already does this though with the progress points for increased
levels of saving. Quite frankly, if you are going for 50% savings, you're not
gonig to get there unless you start modeling really early in the process.

I also think prescribing a certain minimum number of ECMs to look at is
inappropriate and would probably have the adverse effect of discouraging energy
modeling. The appropriate number of ECMs is highly project dependent - based on
building size, scope, complexity, type, level of LEED certification shooting
for, and not least of all the owner's budget. Let's face it, the vast majority
of bldgs out there and that consume most of the energy in the US are (strip)
malls, grocery stores, restaurants etc. These projects barely event have a
schematic, design and CD phase. While we all love to work on the exotic,
platinum level, cutting edge, bldgs that are likely to have a large budget for
design, these are not the majority of bldgs consuming energy. I think we should
be doing more to encourage modeling and energy savings amongst the every day
projects than the "sexy" projects. It seems to me the best way to do this is to
offer incentives in this direction in lieu of prescriptive requirements that
could discourage/put off smaller projects from even attempting to incorporate
modeling.

Julia

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Whole Building Analysis using eQUEST
May 18th: 10am ? 5pm; May 19-20th : 8am ? 5pm

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Visit: www.cgbf.org for workshop agenda and online registration.
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In efforts to summarize the pricing conversation, that the pricing should be
established by modeling complexity instead of by building size, is the
following a fair assessment of what everyone's comments amount to?

LEED Certified: 60-80 hours
LEED Silver: 80-160 hours
LEED Gold: 160-250 hours
LEED Platinum: 250-350 hours

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Sure those may be good rules of thumb but at the end of the day you have to look at the manpower, resources, and experience you and your firm have to apply the correct factor on putting that proposal together.

Just my 2 cents.

William Mak

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Keep:

In efforts to summarize the pricing conversation, that the pricing should be
established by modeling complexity instead of by building size

Delete:

, is the following a fair assessment of what everyone's comments amount to?

LEED Certified: 60-80 hours

LEED Silver: 80-160 hours

LEED Gold: 160-250 hours

LEED Platinum: 250-350 hours

(Hopefully the strikethrough mark-up comes through for everyone)

*David S. Eldridge, Jr.**, P**.**E**.**, LEED AP BD+C, BEMP, BEAP, HBDP*

*From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Arpan Bakshi
*Sent:* Friday, May 13, 2011 10:19 AM
*To:* Julia Beabout
*Cc:* bldg-sim at lists.onebuilding.org
*Subject:* Re: [Bldg-sim] Energy Model Cost

In efforts to summarize the pricing conversation, that the pricing should be
established by modeling complexity instead of by building size, is the
following a fair assessment of what everyone's comments amount to?

LEED Certified: 60-80 hours

LEED Silver: 80-160 hours

LEED Gold: 160-250 hours

LEED Platinum: 250-350 hours

David S Eldridge's picture
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David - Yes. Here are some things that I have found increase model
complexity:

1. Building geometry. Complex building geometry, pitched roofs, dormers,
occupied spaces in attics, etc increase model time. Even if you simply the
model to have flat roofs, there is still time involved for you to figure out
the most appropriate way to simplify the building.

2. Variety of space use. Buildings that have many different space use
types contained within one shell will require additional modeling time.
This reduces the number of zones that can be combined in order to simplify
modeling.

3. HVAC system complexity and novelty. Attempting to model a system that
your energy modeling program is not designed to model can be very time
consuming.

4. Alternatives to model. How many alternatives will you be asked to
compare? Will you be requested to model alternatives to the HVAC system?
Building Geometry? Making changes to these system types is time consuming.

5. Completeness of documents and availability of data. How much time will
you need to spend tracking down information for your model?

The software you use will also affect the difficulty of modeling/changing
the above items.

--
Karen

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Hi,

Thank you for posting those training information and development opportunities. Do you know if any other eQuest Workshop are scheduled for the upcoming month? If it?s the case, it would be greatly appreciated if you could provide us with the location and dates.

Regards,

Marc-Antoine Paquin, ing.

De : bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] De la part de Meera Parthasarathy
Envoy? : 13 mai 2011 10:49
? : bldg-sim at lists.onebuilding.org
Objet : [Bldg-sim] Training: Last call for eQuest workshop next week!

Intermediate - Advanced eQuest Workshop

Whole Building Analysis using eQUEST

May 18th: 10am ? 5pm; May 19-20th : 8am ? 5pm

Eastman Room, Nationwide and Ohio Farm Bureau 4-H Center; Ohio State University Campus; Building 191, 2201 Fred Taylor Drive, Columbus, Ohio 43210

Only three spots remaining!

Continuing Education: This program is approved for 19 AIA HSW LUs. Certificate of attendance and the summary sheet of the program agenda will be provided by CGBF to attendees seeking Professional Development Hours (PDHs). This program would qualify for (19) PD hours.

Registration fee for the three-day workshop is discounted to $399.

Visit: www.cgbf.org for workshop agenda and online registration.

Questions? Email: meera at cgbf.org

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Arpan/Omar and others, apologies for continuing to diverge on the original thread with this sub-topic!

Marcus and other EA TAG members,

I have a few ?informal? thoughts for discussion of the draft language below? sorry for the wall of text, but I hope you?ll find this useful feedback!

1. Overall, the process described below sounds very much like our regular practice with certain clients, who are very into EUI metrics (2030 challenge).

2. I think the credit language should be expanded (and perhaps the onebuilding.org lists should be separately engaged) to suggest more examples of what may be appropriate studies for ?Preliminary modeling.? Many will not be familiar with the process and be stuck for ideas of what to explore. In my experience, such modeling most often focuses on early decisions regarding HVAC system selection, envelope materials/finishes, glazing quantity/placement/orientation, building shades (fixed and otherwise), and active/passive day lighting design. I would note that this is often an ideal time to investigate the energy effects of landscaping on the building, as site layout tends to be locked down early in the design process?

3. Potential for a game-killing conflict: A key feature of such early modeling work is that much of it is very fast and ?loose.? The level of documentation/procedure involved in today?s EAc1/EAp2 validation models is something I?d still call ?intense,? and still takes up a large fraction of the time spent altogether on an energy model. I?m not new to the game, and I?ve certainly learned to streamline my workflow, but I?m sure there?s no place for *that* degree of rigorous documentation in the early stages of design. I suspect many architects would be quick to drop the idea of engaging their energy modelers early on if they become a ?ball and chain? holding up the design process. It would appear on this draft of the language that someone has this issue in mind, but I wanted to vocalize this concern separately so that this doesn?t get missed!

4. Regarding metrics: EUI, due to the 2030 challenge, is the driving force causing local architects to engage us so early on projects, and for that I have to give it props... While metrics like EUI & Carbon footprint may be the best metric for measuring impact on polar bear habitats (?), the best metric with regard to most building owners, and their perception of the ?validity? of the whole process, is unquestionably utility bills. I wouldn?t discourage the use of alternative metrics, but I?d caution against requiring any alternative metrics that may be at odds with the owner?s best interests...

5. Validation models based on the construction documents (as they exist today) are not a bad thing. They are necessary to prevent value engineering from decimating an otherwise great building towards the end of design. I would be wary of throwing out the baby with the bathwater. If preliminary modeling is going to be incorporated into LEED, it should start out as either as a prerequisite or as a separate credit (perhaps pulling points from the large pool available under EAc1)? not as a replacement of the validation model. At some point in the future, they may become one and the same credit, but I think standards broader than 90.1 Appendix G will need to be written and established first, which incorporate practices and procedures for preliminary modeling (as others are saying).

6. I LIKE the inclusion of the ability to use past studies/design. This mirrors real-world practice and permits/encourages proven design to carry into multiple projects. Keep that!

7. I LIKE the focus being on the analysis, not the decisions made. This also reflects real-world decision making, which always balances budget and other constraints against relative energy impact.

8. Julia?s concern regarding prescribing a set # of studies/analyses is pertinent and deserves consideration. Not all projects require a huge investment of time in preliminary studies, and not all projects would benefit? then again, these sorts of studies sometimes cause design teams to learn something they didn?t set out to explore. The bar has to be set somewhere, and I can?t think of a better alternative than a minimum number of studies/iterations per building area (envelope/glazing/HVAC options, etc?).

To the broader concern of inefficient strip mall/prototype projects ? I?d agree LEED likely isn?t the tool to reign that issue in? Developers award this sort of work to design teams who are fast and efficient at cranking out a design that will pass review and minimize first costs/CA. They don?t budget for weeks on quality energy modeling. The only effective tools to drive down such ?fire-and-forget? projects are the prescriptive energy codes, and their effective/actual enforcement by local reviewers. Those codes and their adoption/enforcement drive the market to produce better products at an economical price point.

Hope that helps!

NICK CATON, E.I.T.

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I have been thinking about trying to establish a new
standard at ASHRAE that I tentatively titled:

"Simulation Aided Design for High Performance Buildings"

The new standard, once deveoped, could be referenced by
USGBC and other organizations. The concept is similar to the
direction that USGBC is considering. Attached is a draft
describing the concept. I think having a group of practicing
simulation consultants would be key to making such a
standard usable and adopted.

Please let me know if you have any comments and if you would
be interested in participating in developing a new standard.
If I have enough interest, I will submit the necessary
paperwork to ASHRAE to get this considered.

Thanks

Jason

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All:

Very interesting discussion. I think folks can agree that the US Energy Modeling Services market, snapshot today, can be best characterized as an immature and evolving market - in my opinion, it certainly doesn't fit the description of a commodity service (I see many potential 'customers' searching for the lowest cost' with little understanding of what they are purchasing) and I have mixed feeling about driving the industry towards commodity services. It's the path to scale, which we all want, but if not carefully crafted, will lead to more market confusion and poor quality - no one wins. LEED has played a significant role in creating a market for these services, but, IMHO, it can only 'regulate the market' so far - at some point innovation (people/product/process) needs to carry the market to the next step. Perhaps a better management of expectations between stakeholders would be an improvement..?

Although it is a relatively 'old' document, I attach it here for sharing. At every energy modeling training I conduct, I give away this document and emphasize its usefulness.

1) it's a DOE FEMP publication so it carries branding and credibility WAY beyond me/my firm.

2) There's a lot of good strong 'fundamental' PROCESS information for client education buried in this document

Relevant to this discussion, see .pdf pages 31-32 (of 36).. "Determining Costs and Fees" - I think you will find it an interesting read!

All the Best,

Chris Balbach, PE, CEM, BEMP, CMVP, BESA, BEAP

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As a member of the ASHRAE 189.1 committee (standard for high performance
bldgs). would it be better to incorporate this type of thing into that rather
than starting from scratch? Or, perhaps the std you are talking about could
ultimately get referenced into Std 189.1. Currently, we just switched to
referencing 90.1 App G. There's a number of modelers on the committee. One of
the concerns is trying to minimize the number of protocols a modeler would have
to potentially comply with. Hopefully, these things would ultimately converge.

Thoughts Molly?

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Hi,

I propose a standard on ?intelligent building control? comprising anticipating simulation (forecasting, nowcasting..)

cheers

Gerfried

Please also take my survey: Solar Harvesting in multi storey buildings from the 20th century
http://www.surveymonkey.com/s/HHNBJ2B

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Hi Jason,
could you elaborate a little more on your vision.
From the write up, it sounds to me like you're talking more about establishing a
modeling process protocol - yes?
It also describes ASHREA 90.1 and 189.1 as being prescriptive approaches. But,
both those documents have the alternative (app G) performance based approach
too. As we all know, this established modeling rules and the parameters for
your baseline building etc, but doesn't mandate a certain modeling process (i.e.
when modeling starts in the design, options to be considered etc).
So, do you see your proposed standard as supplementing those in terms of
establishing a modeling process protocol? Or, would your standard also
establish modeling rules and baseline building parameters like App G?

Julia

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Julia,

What I am suggesting has to do with the process of designing
a building using simulation during each step of the process.
It is not about establishing baseline and determining a
percentage savings, Appendix G does that already. I would
hope that both 90.1 Appendix G and this new standard would
be referenced, G for establishing a measurement and the new
standard for establishing a process.

Jason

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Hi all,

The CaGBC Enegy task force and EE Tag has
developed a modeling guide and it is available at CaGBC.org

Martin

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Jason.

I'd suggest you think about an ASHRAE protocol, or Guideline first, then a standard. I also think IBPSA/USA could easily get behind this. I'd be happy to be a part of the group.

Jeff S. Haberl, Ph.D., P.E., FASHRAE

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Arpan.

This is Exactly the place to start, and then add specifics with example input files that could be run by the user. Making this an ASHRAE/IBPSA project would then allow help from ASHRAE staff.

Jeff S. Haberl, Ph.D., P.E., FASHRAE

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If you are going to work in this area around rating and standards for energy use, you will need to apply consistent and localized weather and climate data, so count us in as well, we are happy to help.
Chuck, Weather Analytics

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Agreed. The new credit language for the next version of LEED does ask project teams to establish an absolute performance goal.

Marcus Sheffer

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Not to be a jerk, but to ask an honest question: what is the point? I?ve been involved with ?established energy target? projects and never really picked up on the logic behind it ? I would appreciate a layman?s explanation.

Put another way: If you select an arbitrary EUI or watts per square foot at the earliest stages of design, what have you gained in design process? If/when a project ?meets the goal? mid-design, are future design decisions supposed to de-emphasize energy impact (no!)? If on the other hand, a project finds that target unreasonable down the road, what then?

Not setting a mile-marker like this implies designing the best building you can given the time/budget available and any other constraints? that seems more likely to result in the best end-result to me.

To draw analogy, if design of a LEED (or any energy-conscious) project is like planning a road trip from Kansas to Florida, setting EUI goals seems something like choosing a rest stop by throwing a dart at the map blindfolded. It doesn?t help you get to your destination any more efficiently, it may be far out of the way, and now you?ve got a hole in the wall? what was the point?

Okay, maybe a weak analogy ? chalking it up to a very long week =). Honestly, I?d appreciate someone laying the value behind this approach ? I?m expect the logic does exist, and I just haven?t yet seen the light!

NICK CATON, E.I.T.

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To Nick's point, I feel the energy target is most valuable when coupled with
some sort of Cost Benefit Analysis. If there is a way to incorporate such a
study into the language, we have an energy target the Owner knows he/she can
afford and high performance strategies will not be value engineered out when
the LEED model is built.

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First of all the goal is not at all arbitrary but must be based on an expected outcome within a reasonable expectation. It is informed by data from similar, actual building energy consumption. I don?t think I need to explain the tools one can use to do this.

Your goal (do the best you can) sounds like, ?let?s build an energy efficient building?. This is meaningless. Energy efficiency in the context of new construction is always relative and without a quantification of what energy efficient means this is no goal at all.

Like any early stage performance goal the number is adjustable as more is discovered in the design process. If the target is later discovered to be unreasonable due to a wide range of potential issues, then the target is adjusted.

If you pick your EUI goal the way you describe then yes this is a worthless goal but the key point is that it is never selected arbitrarily.

Marcus Sheffer

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Julia,

I appreciate your thoughts and input.

In my opinion early stage modeling (or a reasonable facsimile) should be required for every green building project. Doing a model at the end for those average projects serves no real purpose and is frankly a waste of everyone?s time (see previous rant). If we continue to allow this for LEED the market will never change. Keep in mind we are talking about LEED and its stated purpose is market transformation. The typical project should not be able to get LEED certified if it works properly in the market. Right now the market has caught up to LEED in many ways. If it does not stay ahead of the market then it ceases to have any meaning whatsoever. So, if not now, when?

I don?t disagree that the current requirements are rather prescriptive and that the number of iterations should vary project-to-project. I am struggling to come up with an alternative that still requires design phase modeling.

One can still earn the prerequisite without early stage modeling, but cannot earn any points for EAc1 as it is now proposed. I don?t think an ID credit would give enough incentive, too easy to ignore. There are prescriptive paths specifically to address small projects.

Marcus Sheffer

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Jason,

I think that you have a very interesting idea. I like that it has come up
in the process of discussing future approaches to LEED EA C1 in regards to
early modeling. Many modelers with experience can provide useful data to
their clients early in the design stages, but as has been said many times,
how is LEED (or other rating agency) to know what was modeled, when, why and
what benefit did it have? In addition, the standard could be used to better
inform the rest of the design team and the building owner what is involved
and expected of modeling at different design phases. I guess I'm saying -
count me in!

--
Karen

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While we have Marcus's attention, I would like to rant !

Since the next version of LEED will have a credit dedicated to peak demand
reduction, can we make it so that credit cannot be taken for EAp2c1 for
thermal energy storage systems?

The peak demand credit already addresses reduction of power generation at
the power plant scale, so optimize energy performance can be more true to
reduction of site energy.

Too many towers apply no energy conservation measures to internal gains and
simply transfer their cooling requirements to their CALMAC tanks.

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Ah...thanks Jason. I see now.
Sounds like your concept will complement App G in 90.1/189.1 well.

Molly, perhaps it's something we could ultimately reference in 189.1 and
interact with their potential committee.

Julia

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While I conceptually agree with and understand the kbtu or watts/sf approach, to
me, there seems to be some series issues with it in reality.

First, I don't agree that generating or coming up with appropriate target values
during design is always (or even frequently) an easy thing to do or easy data to
find. It depends on your bldg type. I do a lot of labs and hospitals.
Manufacturing and industrial use bldgs can have the same issues. Good EUI data
is not easy to come by for these bldg types - partly because the user equipment
that is installed in them can be a big portion of the energy demand and
consumption and it's always changing and can be very specific to each client.
For example: is it a community hosptial with more modest and generic care
provide?....a state of the art hospital with specialized care functions?....does
the lab have primarily biology or a chemistry functions....etc etc. These
things all affect the EUI. In my opinion, the best resource for this data is
actually utility companies based on data from similar customers, but that data
is not generally publicly available and/or the population of similar comparable
buildings may be small and difficult to relate to your bldg.

Second, quite frankly, in my opinion, DESIGN phase energy models are poor
predictors of ACTUAL bldg energy use. They are best at predicting RELATIVE
(comparative) energy use. This is not because the tools are not good or
inaccurate but because we and the owners are so poor at predicting how the bldg
will actually be used, weather, etc. One additional factor, is what equipment
will actually be installed. It's not uncommon for the technology to have
changed bewteen the time that we start design and the time the equipment is
actually purchased closer to the end of construction. All these things effect
not only the equipment w/sf usage but the ac w/sf usage etc. So, there seems
to me to be a serious disconnect to me if we talking about setting energy
targets during DESIGNbased on statistical data of ACTUAL energy use and trying
to use those figure during the design phase for predicted energy use. Again, I
love the idea but are we really there yet in reality. It seems to me we need a
lot more data that doesn't exist yet - and mechanism to collect that data.
(CBECS etc are good, but the population and variability for bldgs of these types
has a long way to go).

I missing something about what's being proposed/talked about?

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The primary purpose is to get the conversation started, early. It is an opportunity to educate the owner and the team about energy. In my experience the majority of designers can?t even tell you the metric for comparing building energy consumption. I have often had this conversation early in the project design and have been met with blank stares. It is incumbent upon us who do understand these energy issues to get the conversation started. Caveat the heck out of the goal, explain the limitations, discuss the relative vs absolute metrics, be open about the issues ? so that we can raise awareness one conversation at a time. This is the power of a market transformation tool like LEED. It enables us to have these conversations.

I agree that both of these items are potential issues, talk to your clients about them. If you don?t have a goal, how do you measure success?

Marcus Sheffer

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The primary purpose is to get the conversation started, early. It is an opportunity to educate the owner and the team about energy. In my experience the majority of designers can?t even tell you the metric for comparing building energy consumption. I have often had this conversation early in the project design and have been met with blank stares. It is incumbent upon us who do understand these energy issues to get the conversation started. Caveat the heck out of the goal, explain the limitations, discuss the relative vs absolute metrics, be open about the issues ? so that we can raise awareness one conversation at a time. This is the power of a market transformation tool like LEED. It enables us to have these conversations.

I agree that both of these items are potential issues, talk to your clients about them. If you don?t have a goal, how do you measure success?

Marcus Sheffer

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There is a famous study ( I don't recall the link to it) which shows that almost 50% of LEED buildings consume as much and more energy than non LEED buildings.

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Your concerns make a lot of sense. I think theissue is to give Watt/sft, or per user, bed, etc. for the building envelop only without specialty equipment load. Usually, equipment selection for specialty buildings such as labs are not within the Architect or the HVAC engineer scope of work. This might be accounted for under different category if applicable.
H. Abaza

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I?m not sure it is a completely fair comparison straight up ? many of the
LEED for New Construction projects that I see have extremely high demands
and expectations from their owners about productivity and features. Many of
these that I have experience with are healthcare, higher education, and
laboratories, which as Julia B. mentioned have a huge impact from the
operational characteristics that can be influenced at the time of design,
but are only partially inside the sphere of influence for the architect and
engineers as the building operates. Also lots of commercial high rises for
banking institutions with heavy computer loads.

Especially as the energy code squeezes the ?regulated? energies down to
lower and lower levels, the process energy usage becomes a greater percent
of the total which could be a major factor in why many of the buildings from
the study weren?t performing as modeled ? the energy end-use that is the
least influenced by the design team is becoming a larger percentage of the
total.

Since the energy savings percentage currently utilized is a relative
baseline, you may see some variations in absolute EUI between two
neighboring properties ? in fact I?d expect it! If a building was going to
be required to save 10% versus 90.1 and a peer building was built nearby
that was ?equal? to 90.1, the variances in the process loads, system
mapping, building geometry, occupied hours, etc. could be just as important
variables than LEED registration or non-registration to determine which had
a higher EUI than the other.

It will be very difficult to account for the geometry and occupancy
variables when determining the proposed target EUIs. Also how to even
choose the metric as a basis between site, source, energy cost ? this is
going to be very difficult to implement. What about the Durst Organization
building that has cogen, heat recovery for absorption, and thermal
storage?definitely won?t fit this target EUI mold, but overall the
strategies were recommended and implemented by a savvy owner.

Specifically about the ?famous study? I could also make an argument that
relating to energy usage, there are certainly many designers (many of
ourselves on this list I hope!) that work on projects where we?re using
efficient systems and equipment as the basis regardless of LEED registration
? who is to say that an owner can?t make an initiative for an energy
efficient building without LEED certification? 90.1 and IECC have been
advancing quickly, and even the code minimum building built today should be
a pretty good performer.

So to make a long story short, I think the idea of having the EUI
conversation is good and agree that any EUI target would have to be subject
to adjustment, and that more emphasis/incentive should be placed on the EBOM
rating system as a tool for improving the operations of the buildings for
the remainder of their lifetimes. I don?t see how EUI targets will work in
a formulaic/prescriptive way as part of a LEED credit or prerequisite in
place of the relative baseline we use now without a major change in how the
project is approached from the owners. The larger goals should be
achievable without this step in my opinion, and having the discussions on an
individual project basis.

David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP

*From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Hussein Abaza
*Sent:* Saturday, May 14, 2011 7:47 PM
*To:* sheffer at energyopportunities.com
*Cc:* bldg-sim at lists.onebuilding.org
*Subject:* Re: [Bldg-sim] Energy Model Cost - best design doesn'tequalmost
LEED points

There is a famous study ( I don't recall the link to it) which shows that
almost 50% of LEED buildings consume as much and more energy than non LEED
buildings.

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Yes I think it is the same study which showed LEED buildings were 25% to 30% more energy efficient than average. There was considerable debate about the interpretation of the data.

The purpose of my post was how do we get folks to use modeling on LEED project to make them more energy efficient. Some folks just complain about LEED without offering a better alternative. USGBC is seeking your good ideas to make it better, more useful and effective.

Marcus Sheffer

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I guess this is where I enter this interesting discussion. The selection of an EUI should definitely not be arbitrary. In fact, the LEED-EB rating system already provides a good example of how to choose an appropriate target EUI: Energy Star. Target Finder can be used for this, or you can build your own spreadsheet from the technical descriptions at http://www.energystar.gov/index.cfm?c=evaluate_performance.bus_portfoliomanager_model_tech_desc. Most of the variables you need to set the target EUI are schematic level: anticipated hours of operation, gross floor area, number of occupants, HDD/CDD.

At the same time, looking at the AIA design milestones, I would be concerned if a project experiences changes that have a significant impact on energy consumption after 75% CD, maybe even 50% CD depending on the project. I could see a late decision to use MERV 13 filters causing an increase in fan energy, but that decision can also be mitigated through other variables such as filter surface area.

There needs to be some change to the process to prioritize the right decisions first. Energy needs to be part of the decision model for a building at the early phases of the project, part of site selection for projects that are defined that way or part of the pro forma for developments that start with a fixed site. In many cases, it is part of those, but with no connection to the remainder of the decision model.

On your analogy, Nick, I?d suggest that using a goal of designing the best building possible within time/budget constraints is more akin to just getting in a car and driving. Who?s to judge if you actually arrive at your destination? You might be able to say you had a good trip and the drive was a success, but would it have been more successful if you knew where you were going and how to get there most efficiently? However, starting with a destination in mind allows you to better plan your trip from a time/budget perspective. Just having an EUI goal doesn?t mean that you ignore the energy impact of decisions. It just means that you have another criteria to let you know if you?re making the right decision. The flip side is also true: if a decision is made late in the design that negatively affects EUI, you can catch it. The EUI goal is more like having a GPS on your driving trip, letting you know if you make a wrong turn along the way.

Jeremy R. Poling, PE, LEED AP+BDC

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Here is a link discussing leed and the 50% of the buildings consume as much
energy as non Leed buildings.

http://www.youtube.com/watch?v=mvCP3s7Xq48

After seeing this video Henry Gifford became one of my new heros.

Green is the new Red.

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Read the study for yourself - http://www.newbuildings.org/sites/default/files/Energy_Performance_of_LEED-NC_Buildings-Final_3-4-08b.pdf

Here is another study analyzing the same data - http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/nrcc51142.pdf

Marcus Sheffer

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Hi Marcus,

Thanks for asking us for our feedback. I welcome this opportunity to give
you some information regarding my experience as a LEED modeler and some
ideas I have for making the modeling part more useful.

Many of the LEED projects I work on do not use LEED as a design tool. For
these projects, even though my initial proposal includes schematic design
and design development modeling, I am usually asked to complete only the
final LEED model and LEED model documentation, ie "please do only what is
required for LEED." This means that the modeling tool is not being used to
make design decisions.

I like that the new EA C1 language talks about using energy modeling to
inform design decisions, and I think that it would be helpful to engage this
list-serve to determine the best way to bring that goal into the LEED
requirements. One thing that comes to mind is that I use many tools during
design development phase energy modeling. Often, I'll complete thermal
modeling of building envelope details in order to help the architect reach
achieve a higher overall R-value for envelope constructions. While not a
whole-building energy analysis, this is often one of the most illuminating
discussions I have with architects. Often I will run a simple model with
R-20, R-30 and R-40 walls, we'll look at overall energy use differences and
the engineer will look at benefits to system sizing and then the major
conversation is: how do we construct the building so that we actually
achieve an overall R-value that meets our goals, not just in the center of
the wall.

Sometimes I prepare a detailed report for model alternatives, the best
results come from sitting down with the design team, running a number of
alternatives and viewing and discussing results all at the same time. The
LEED documentation requirement for this portion of the credit should be
similarly flexible.

Thanks for your time,

--
Karen

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The NBI report and subsequent reanalysis is interesting but they and Marcus' emails beg the question: What is LEED's energy efficiency metric?

LEED NC & CI reference 90.1 ECB and Appendix G which use energy costs. LEED EBOM references Energy Star which uses source energy use intensity. Other programs and experts use site energy use intensity or greenhouse gas emission intensity. USGBC should pick its metric and craft all versions of LEED around it. I understand it is a very nuanced and charged discussion involving modeling protocols, metering protocols, fuel switching, district energy systems, regionalism, current/future carbon content of electricity etc. The more I look at Energy Star the more I respect their approach that source energy is the fairest and we just do not have enough data about some building types to say who the leaders of that type are.

Please don't show me more reports that we gave away plaques based on modeled dollar cost savings and then got worked up over metered site energy vs. non-calibrated modeled site energy. There is a better way. Lead us to it.

Paul Riemer, PE, LEED AP

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All:

I've been intrigued ever since I saw RMI's presentation on how target EUI's were set for the showcase Empire State Building renovation - where an innovative approach was used to define the building's "technical potential to achieve" and then measuring success by the team's ability to deliver a cost effective project than meets the "technical potential to achieve" as much as possible, while balancing all other needs. Here's a nice summary - http://www.retrofitdepot.org/Content/Files/ESBCaseStudy.pdf

I've been thinking that, in general, re-framing energy performance success (i.e. EA C1 points) not as a "% better than an Appendix G Baseline" but to "% below the building's semi-unique technical potential to achieve" - might have interesting and positive effects. By that I mean, imagine an office building designed and predicted to consume (on a site EUI basis) an EUI of 89 kBtu/ft2, while the technical potential to achieve might have been determined to be 70 kBtu/ft2. This represents a (1-(89/70)) = 27% gap, which say falls between 25% and 30% and it worth 3 EA C1 pts.

The ASHRAE Standard 100 Revision Committee has been working with some unique "hybrid" approaches combining "prototype or reference building energy models" and CBECS data to generate regional EUI targets based on building composition, building size, and building operating hours. The proposed revision of ASHRAE Standard 100 (not yet out for public comment) will incorporate a procedure for generating a building specific EUI for setting retrofit performance targets. Here's a link to a presentation by Terry Sharp where he describes the basic concept under "Option 3" - http://tc76.org/docs/programs/ASRHAE%20std%20100%20%20Sem%2020102520June_Sharp.ppt Remember that EPA Target Finder is based exclusively on the EPA Portfolio Manager models, which are based on a number of different years of CBECS surveys, dependent on the space type.

It's not too much of a stretch to imagine, following the general principles from above and the methods described in proposed revision to Standard 100, to be able to generate a unique 'semi-custom' EUI for your building project - maybe it might look something like this:

1) Download appropriate DOE prototype model(s)
2) Add appropriate exterior shading (adjacent buildings, etc.)
3) Replace building fabric elements with appropriate benchmark elements for your building type (retrofit / new construction)
4) Replace 'asset' related elements (lights, equipment) with appropriate benchmark elements for your building type (retrofit / new construction)
4) Generate site EUI results with a weather file for your location.
5) If necessary, combine (area weight) EUI to result in whole building "Potential to Achieve"

In this way, one ends up with a semi-custom EUI performance target to measure success against - a target could be "better defined" than what you can currently get from EAP Target Finder. I can envision a consensus document which lays out a specifications and procedure for allowable alteration of the DOE models, in order to generate the "Potential to Achieve EUI", after which the % difference from an "As Designed" case translate to EA C1 points. I know this is NOT the original purpose of the DOE Benchmark Buildings, but with careful thought, and community consensus, I think a process of something like this may move the centroid of the community in the right direction. The energy usage 'goal' would be known as soon as the program was set, and the design team can react from there. Also, the resulting "As Designed" model could be more useful, at would be meant to represent actual building performance to the best of the knowledge of the design team.

Thoughts?

All the Best,

Chris Balbach, PE, CEM, BEMP, CMVP, BESA, BEMP, BEAP

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Paul,

The next version of LEED will approach a more standardized metric (EUI Source Energy) but still include cost as a metric as well. For those who feel strongly that only actual energy use should be used for green building certification the LEED EBOM methodologies will be allowed into LEED BD+C projects.

USGBC is trying hard to lead us to that better way. If you know the better way please share.

Marcus Sheffer

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One variation I was considering to EUI was to look at Kbtu per annual occupant hour vs. Kbtu per area. This came about when I wanted know how to evaluate some operational alternatives such as extending the hours of operation for a facility, or looking at an office running with a rotating staff all working 4x10 hour days a week vs. a smaller static staff in the same building working 5x8 hour days a week. Kbtu/sf2 alone didn't help here, but looking at Kbtu per annual occupant hour did.

Extending operational hours will clearly increase your Kbtu/ft2 (EUI) but the question I wanted to answer is if those extra occupant hours come at a lower energy impact per occupant hour than the baseline case. "Kbtu/ annual occupant hour" addressed this. Is there a similar metric that anyone else is using?

David Goldwasser, LEED AP

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Marcus, Jeremy, David and others:

Thanks so much! Your responses helped fill in a gap ? in my experience, establishing early EUI targets has indeed felt ?arbitrary,? and it?s precisely because of the litany of issues brought up regarding what really makes for an appropriate comparison.

The exercise of determining an appropriate EUI target has proven deceptively challenging, in my experience. The energy star target finder will generate a number to run with minimal effort, which is great, but when that target is scrutinized by skeptical minds, it can be hard to justify/defend how ?realistic? that target is for a given project, considering all the unknowns behind the figure. These include attributes like age of construction (for renovation projects), unique building geometries, scheduling and more. David?s response summed up some of the unknowns well, imho.

Suffice to say, some of us in the energy modeling trenches could use some assistance/reassurance in methods of establishing well-grounded EUI targets? In constructing ?Implementation? language for the ?preliminary modeling? credit under discussion, I would personally like to see some specific guidance/examples to this end, or else a reference to a standard illustrating the same. I feel somewhat disillusioned regarding EUI targets and their resulting effects on the design process, but it?s apparent others have had some pretty positive experiences, so I?d like to learn more!

NICK CATON, E.I.T.

PS: I know written words don?t always read the way they were intended, but my query/analogy regarding EUI targets is not intended to criticize or judge others? practices! I only mean to illustrate what I?ve been struggling with, if only to share experiences and learn from the discussion!

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LEED always encourage ciritisizers??to light a candle rather than to curse the darkness. ?Certainly building on LEED's success?is the correct approach. All?the suggestions that we hear (including mine) are good hopes,?but I think LEED has the resources now to do some research to validate?the viability of the different alternatives and point capturing. For example,? do we have any research that shows the benefet?of assigning parking spaces to?hypbrid cars, or?bycicle racks, etc??

H. Abaza

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I did some pre-RFP modeling for Denver Housing Authority to try to help
them develop realistic & useful energy metric design goals for a recent
project. We ended up setting a percent energy cost saving goal (ie
LEED) along with a site /lbs CO2 emissions/ SF/ goal for the design. We
started out with a kBtu/ SF metric, but weren't happy with the way this
quantified environmental impact in Colorado. This is because most of
our electricity comes from coal and it's CO2 intensive relative to
natural gas, but looks better than natural gas when looking at site
kBtu/ SF. It's interesting how this will change design decisions
compared to just looking at energy cost savings relative to the ASHRAE
90.1 baseline; it's much easier to hit 50% savings with an all electric
building, but CO2 emissions go up.
The metrics DHA ended up included in their RFP came out of modeling the
actual building type in the actual location of the project, so we were
comfortable with them being reasonable design goals for the
'as-designed' building. We also made sure that people understood the
difference between 'as-designed' modeling and 'operational' building
energy use. It was great to work with a really progressive client who
gets it and wanted to look at these details closely.

*Aleka Pappas*

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It's interesting that just as we are having this discussion, the budget for
CBECS is going away:
http://blog.bepinfo.com/2011/05/death-knell-for-energy-star-building.html.
So even one less source of EUI information for people to use. Ironic!

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It's like herding cats.

Our practice is heavily involved with Government projects, all of which need to comply with the various laws (EPACT and EISA) and Executive Orders that drive building energy savings performance in addition to project specific performance within the LEED rating system.

It is an interesting analysis process, as we have to evaluate energy (kBtu) vs. cost (utility) vs. fossil fuel use (FFU) (including utility grid impacts) savings, all with the goal of meeting minimum performance goals of 30% for EPACT (a 90.1-2004 baseline, which can be increased on an agency/department basis, as in one case has been raised to 50% energy savings compared to a 90.1-2007 baseline), minimum 10% (which usually ends up 30% or higher) for LEED, and a minimum 55% FFU reduction for EISA (ratcheted up to 100% avoidance by 2030).

With the singular exception of the EISA FFU requirement, all measures to achieve stated goals must be proven Life Cycle Cost (LCC) effective or compliance can be waived.

While a DOE proposed EISA ruling, if promulgated, pushes off the EISA FFU reduction requirement for at least one year, this one law (if unaltered, by law or interpretive rule) is the heavy hitter as it requires either a substantial change in our utility grid system (to eliminate fossil fuels) or forces the project to be off the grid (or forces the Agency or Department head to officially ask for a waiver for non-compliance).

Why do I bring all of this up?

If USGBC is pursuing the goal of seeking energy savings (kBtu) in addition to utility savings (and they can be at cross purposes, as with thermal storage), then shouldn't it also seek to reduce greenhouse gases, as in fossil fuel reduction? A balance could be sought, as an example consider that a tri-generation process can produce less greenhouse gases compared to an open-loop heat pump approach given the fossil fuel type used by the electric utility provider.

Of course, to be technically correct, there are the greenhouse and environmental impacts to be considered with natural gas fracking (also with coal mining and off-shore drilling).

I'm sure there are plans for expansion of our nuclear power generation on the grid, with its own inherent concerns.

Deep geothermal, if available, does seem to offer the best promise for a 24 hour supply source. Solar, hydronic and PV just doesn't seem to be LCC effective except for the most expensive utility rate structures.

David Ellis

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The EAp2c1 credit for thermal storage would be minimal I think but it does
exist as currently written. Since the proposed metric is a combination of
cost and EUI, thermal storage should do better in one and probably worse in
the other.

Not sure how we could separate out the systems in the models for EAp2c1, but
you make a good point about potential double counting (not always a bad
thing for LEED if it is something we really want to encourage like
renewables).

Marcus Sheffer

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Hi Karen,

I certainly agree that the enforcement of the requirements should be
flexible. The difficulty we face is related to the review of the
documentation submitted. Individual subjectivity in the review process can
sometimes lead to inconsistency, so the more flexible, the more subjective.

Appreciate the feedback.

Marcus Sheffer

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Interesting ideas Chris.

One of the biggest obstacles in design is bridging/explaining the gap between absolute goals and relative comparisons.

I appreciate all the comments received.

Sounds like perhaps we need a benchmarking standard/guideline and an energy modeling process standard/guideline to reference for LEED. Jason has proposed to get the later started. Anyone know of anything in existence or getting started to help with the former for new construction projects?

Marcus Sheffer

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Carbon was considered as a possible metric for LEED 2012. It was replaced
with EUI because of the weighting criteria applied to the credits. Since
carbon (i.e. climate change) was already being used to weight the number of
points, it was felt that it should not be both a metric and a weighting
criteria.

Marcus Sheffer

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I am very passionate about a benchmarking standard/guideline, and there is a lot of research in this area. I will be glad to volunteer and help in this if LEED or any other organization/company is willing to lead the effort.
Hussein Abaza, Ph.D

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RE the potential for double counting and thermal storage, has any thought been given to the value/detriment of storage systems depending on carbon profile of off-peak vs. on-peak emissions? I could perhaps see allowing the "double counting" (this might be too much effort to implement) if the thermal storage CHW production uses renewable or a cleaner-than-gas (assumed for peaking units) electricity generation source, but not if the baseload/nighttime generation uses more carbon intensive generation mix.

We've add projects with both sides of the coin, and though the financials penned out in favor of TES, it can seem a bit counterproductive environmentally on one side of the coin.

Paul

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The 50% Savings Advanced Energy Design Guide for K-12 School Buildings (publication this fall, free download available from www.ashrae.org/freeaedg) will include a chapter on EUI targets for schools. This chapter provides a methodology for determining targets for your specific project and provides targets (by end use and climate zone) for reference. The EUI targets that are provided were generated from energy simulations using the DOE reference building schools. A draft of the chapter can be downloaded from ftp://aedgpub:3a$ts!d3 at ftp.ashrae.org. The chapter is provided in DRAFT form and electronic dissemination is limited to Bldg-Sim mailing list members only. This file may not be stored on a computer system for the purpose of additional distribution. A physical copy may be printed from the electronic file only for the personal use of the Bldg-Sim mailing list member. The electronic file will be available through June 30 on the FTP site.

A procedure similar to what Chris outlined will be added to the chapter before publication (it is not currently in the draft). It will discuss a way to set your own energy target based on a project specific energy model. In summary, the steps will be as follows: (1) start with the appropriate DOE reference building school, (2) modify the model to include your schedules and climate information, (3) add specialty space types or unique plug loads that are not captured in the DOE model, and (4) run a simulation in your climate to set your own baseline. Your target is 50% of this EUI.

Any feedback to the draft or this procedure would be very helpful.

Best regards,

Eric Bonnema

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Considering that the NREL benchmark buildings generally under-predict when
compared with CBECs, EUI targets generated from those models wouldn't
necessarily be very useful.

Morgan Heater, P.E.

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The DOE Reference Building models (i.e. NREL benchmark models) were generated as starting points for research oriented simulations. They were not developed to match CBECS performance data. However, the reference building models do provide a good starting point for energy studies on specific buildings. The key is to modify them to your specific application with the correct schedules, special loads, etc. From our experience with new and retrofit projects, modified reference building models do provide good EUI targets for projects.

Michael Deru, Ph.D.

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