[Bldg-sim] LEED - What does it take?

[Joe Parker]

I have been following this discussion, not as an engineer or modeler, but as
someone interested in the factors influencing the financial return on energy
saving products.  My concern is in the same area as Vikram Sami expressed
below but even a little deeper.  Vikram rightly notes that energy costs vary
from location to location so a unit saved one place is not necessarily
comparable to another location.  I would add two other factors that are very
important in an energy efficiency decision - rate structure and time of
energy saving. The bottom line is that an energy unit saved is based on both
the rate structure and the time of day that negative watt was earned.

 

Rate structure factors such as demand response, peak demand, and off hours
rates drive the value of reducing energy usage.  Some utilities offer very
low rates at night.  If you have a building element - such as our Phase
Change Material or Ice Energy's storage process - that can store energy
during the low rate hours; then this energy is available to offset demand
during a peak rate periods.  

 

If a product can reduce the energy usage during a high rate period in a high
rate location then that energy saved should command a higher value in not
only a LEED certifications calculation but in calculating the value in an
energy modeling program for ROI.

 

I am not an expert on energy modeling nor do I know about all the models
available, so this comment needs to be understood from my product
perspective and most likely, my limited knowledge.  It seems to me that most
models are driven by weather data.  Weather data and location drive the
design of the building shell. A building is built to live and work in.
Efficiently managing the internal environment demands managing energy use
for not only the effects from the outside environment but also the comfort
and use of its occupants.  I am excited about the future of building control
systems based on sensors.  This trend will help solve the problems I noted
above but they do more than just save units of energy, they will save energy
at the most expensive moments.  

 

As an MBA - not an engineer - the key here is twofold.  How much energy can
I save with the package of energy saving options available to me and what is
the cost of a unit of energy when I save it.      

 

Joe Parker

CEO

303.931.1606 global mobile

866.616.9870 global fax

 <mailto:brianmurphy at esBits.com> joeparker at esBits.com

 <http://www.esbits.com/> www.esBits.com

 

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From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Sami, Vikram
Sent: Monday, January 21, 2013 7:43 AM
To: Nick Caton; Dennis Knight; RobertWichert
Cc: bldg-sim at lists.onebuilding.org; EnergyPro at yahoogroups.com
Subject: Re: [Bldg-sim] LEED - What does it take?

 

My two five cents - adding to the many cents already thrown in the pot. 

 

.       LEED & Appendix G at this point are based on energy cost - not raw
BTUs or carbon. So the relative costs of your fuel mix will have an effect
on final scores (in a place where electricity is cheap and heating fuel is
not - you are likely going to have less credit for your SEER rating). I
don't agree with it, but that's how the system is set up.

.       The effectiveness depends on your baseline energy usage. For example
- if you have a building that has very small HVAC component, even a 50%
reduction won't get you to 10% overall. 

.       LEED addresses consumption and not efficiency (which is a good
thing). So you get credit for 'driving less'. Hours that you don't need to
run your HVAC = money in your pocket (the envelope leg of Nick's tripod
analogy). 

.       It also depends on other factors like how you deliver the energy.
For example - using hydronic cooling & heating will likely save you more
energy than an all air system with a higher EER on the chiller. Using a
waterside economizer goes back to the 'driving less' analogy. Hydronic
systems are also less prone to reheat (simultaneous heating & cooling)
issues that you have with all air systems. 

 

The way I like to approach LEED projects is to go after the intent of the
credits rather than the point - you'll be surprised at how often you end up
with a higher LEED score when you do. 

 

Apologies to Robert if this doesn't directly respond to the original
question. 

 

 

 

Vikram Sami, LEED AP BD+C

Sustainable Design Analyst

1315 Peachtree St. NE, Atlanta, GA 30309

t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com
<http://www.perkinswill.com/> www.perkinswill.com

Perkins+Will.  Ideas + buildings that honor the broader goals of society

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Wednesday, January 16, 2013 8:09 PM
To: Dennis Knight; RobertWichert
Cc: bldg-sim at lists.onebuilding.org; EnergyPro at yahoogroups.com
Subject: Re: [Bldg-sim] LEED - What does it take?

 

Man, every time I start a reply 3 more have come out, haha!  I think we're
all pretty much on the same page though =).  This is largely written in
response to Robert's most recent reply:

 

Applying 10% improvement to lighting/mechanical equipment/envelope is merely
a strategy for achieving performance figures in the right ballpark once
energy modeling begins.  No more and no less.  I can attest this has worked
well for me in the past, but I never meant to imply "..and you're done."  

 

This is just a means of getting the ball rolling and ensuring the important
decision makers understand they have a role to play.

 

I agree completely regarding the limits of SEER and every other standardized
efficiency rating I've worked with.  Seasonal and steady state efficiencies
are NEVER direct indicators of actual system consumptions, they are merely
representations of performance under specific conditions.  That said, they
do have a useful time & place which occurs at the beginning of a project,
before a more detailed analysis can be made with energy models or otherwise.
SEER may or may not be an inadequate efficiency metric for your specific
climate, but that doesn't change what defines your baseline equipment. 

 

If the goal is simply to reduce heating and cooling energy consumptions of
your HVAC systems by XX%, and I can't build something resembling the final
design for an energy model, I simply can't offer a better answer than
"improve your heating and cooling efficiencies by XX%," recognizing this
alone will not get you there if your lighting consumptions and envelope
performance do not do their part.  

 

A black and white answer to what minimum performance is required of any
system for any specific LEED project goal is truly unapproachable until you
start the energy model that will determine the results ;). 

 

As it happens however, I can answer Robert's most recent hypothetical almost
directly:  I have performed a preliminary study for a building in the
vicinity of El Paso, TX using 15 SEER AHU's with energy recovery.  I
determined a 30% LEED improvement would have been attainable using an
envelope matching 90.1 baseline constructions, but this entailed a roughly
50% LPD reduction (I would have performed the lighting design and can attest
this was achievable), and a healthy laundry list of EEM's for mechanical,
with a heavy service hot water equipment load helping things along.  

 

So to wrap up, I'd say 15 SEER units absolutely can be one part of a bigger
picture achieving a 10% LEED performance rating.

 

Apologies for the walls of text. sometimes the quick & easy answer is "there
aren't any quick and easy answers!"  Hope this discussion is helpful to you
and yours in any case!

 

~Nick

 

cid:489575314 at 22072009-0ABB

 

NICK CATON, P.E.

SENIOR ENGINEER

 

Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617

www.smithboucher.com 

 

From: Dennis Knight [mailto:dknight at wholebuildingsystems.com] 
Sent: Wednesday, January 16, 2013 6:24 PM
To: RobertWichert
Cc: Nick Caton; bldg-sim at lists.onebuilding.org; EnergyPro at yahoogroups.com
Subject: Re: [Bldg-sim] LEED - What does it take?

 

Robert,

Simple answer is "No" - that is my point - it more than likely never will.
You have to include all of your proposed energy conservation measures that
you are likely to apply into a single model with your user and climate/local
specific schedules and profiles included to see what the aggregated savings
maybe.  You can run multiple models changing only one component to do some
sensitivity analysis to see what variables/measures may give you more
dramatic changes in total energy consumption, cost, carbon  emissions,
indoor comfort, life cycle cost, life cycle assessment, etc.  (which ever
your client and you are using as your decision making criteria).

As for the question regarding 10% energy reduction using 15 SEER equipment:
I've gotten 10% better energy performance using 90.1 minimum SEER compliant
equipment and effecting change in lighting power density, lighting controls,
controllable plug loads and better envelope/less infiltration, better
ventilation and properly downsizing the mechanical systems.  You do not
always have to improve the mechanical efficiency of the HVAC equipment to
achieve an energy efficiency improvement target.  It is a whole building
analysis that the owner's O&M behavior can have a major impact on.
Conversely, I've had bleeding edge efficiency and complexity in the energy
using systems at some facilities and the buildings perform worse than an
minimum code compliant building  or a local median EUI when a custodian who
knows how to turn things off at night could have done better - when the
owner does not understand how the design team intended the building to be
operated when they made their analysis.  For example, I just investigated a
net zero energy house that was donated to an international non-profit.  It
has 22 SEER geothermal heat pumps, an envelope so tight it had no air
measurable leakage at 80 pascals, LED lighting, solar water heater, energy
recovery ventilator, solar PV, SIPS panel wall system, commercial grade low
e windows and a sophisticated energy monitoring system.  It is built right
next to a conventionally built house, stick framed, minimum residential code
compliant construction with 13 SEER air source heat pumps.  Both are
occupied by single mothers with two children.  The net zero house has worse
energy performance than the code minimum house almost entirely due to
occupant behavior. I personally did not believe you could operate that house
such that it would ever consume much energy, but you can.  In this case the
owner was not determined until after the house was constructed and did not
have a stake in the design and was not trained on the special features of
the house when it was offered to her.  Now that she has been educated I can
see some reductions - but the house is still falling way short of its goal
of net zerobecause the owner is just unwilling to change her lifestyle no
matter what the nergy costs are.

Dennis

On Wed, Jan 16, 2013 at 6:28 PM, RobertWichert <robert at wichert.org> wrote:

I suppose the modeling software and how it treats energy might have
something to do with it too (Note to CA and TDV), but for starters the
modeling software will look at actual conditions in the particular place
where the project is located.  As an absurd case, if there was no cooling
needed, an infinite SEER would show no improvement.  SEER is for "typical"
and each project is not necessarily typical.  For somewhere with a high
cooling demand, SEER should have a greater effect, but cooling is only a
small part of the energy budget.

I can appreciate that with "10% better walls, 10% better windows (or how
about 10% less windows), 10% lower lighting wattages, 10% more efficient hot
water, all compared to the standard, you could get 10% better using a SEER
14.3, but I have never gotten that result.  I suppose that I need to look
harder at the other legs on the stool.  For me, I need SEER 17 to get to 10%
better in California with a somewhat lopsided stool.  I am curious what
experience others have.

The theoretical answer may be "Make everything else use 10% less energy than
standard and have a SEER 14.3 AC unit, and you're done" but to be honest,
that doesn't ever work for me.

Maybe a better question is; have you ever gotten 10% better than ASHRAE 90.1
with a 15 SEER AC system?  In a real project with real people fighting over
costs, etc.?




Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060 <tel:%2B1%20916%20966%209060> 
FAX +1 916 966 9068 <tel:%2B1%20916%20966%209068> 
 
 
 
 
 
 
 
===============================================

On 1/16/2013 2:25 PM, Dennis Knight wrote:

Robert, 

SEER is a seasonal energy efficiency ratio and is unitless.  It is the
"cooling output during a typical cooling-season divided by the total
electric energy input during the same period":
http://en.wikipedia.org/wiki/Seasonal_energy_efficiency_ratio.  A unit with
10% or better seasonal cooling energy efficiency over a 13 SEER unit would
have a SEER rating of 14.3 or greater (1.1x13) if all other operating
parameters were held constant.  See link for definitions and other
references.

Dennis

On Wed, Jan 16, 2013 at 5:11 PM, RobertWichert <robert at wichert.org> wrote:

My current project has very good windows, "standard" walls, you're right
about the lighting, it's right on budget (but residential doesn't really
have a budget, so the small common areas are right on budget), better than
standard roof.

I absolutely agree with you, Nick, on achieving 10% better, but all the
trades point to the others.  It's kind of comical, actually.

I guess my question on this list could be rephrased, using your approach, as
"What SEER is 10% better than SEER 13?"




Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060 <tel:%2B1%20916%20966%209060> 
FAX +1 916 966 9068 <tel:%2B1%20916%20966%209068> 







===============================================

On 1/16/2013 12:34 PM, Nick Caton wrote:

A very simple way of looking at LEED & energy, which I come back to often
for discussions on that level, is to consider a building's performance like
a tripod with three important legs:  Lights, Mechanical, and Envelope.  If
any of those legs is too short, the tripod falls over.

Building on that analogy, to do 10% better than a LEED baseline, a good
starting place is to have at least:
-  10% better lighting (10% lower LPD),
-  10% better HVAC & hot water heating (10% better efficiencies), and
-  10% better envelope (10% more insulation in walls/roof, 10% better
windows).
For each of these, you can source the baseline/prescriptive levels from the
standard of your choosing.

Overperforming in one area can sometimes make up for underperfomance in
another, but with diminishing returns.  Amazing HVAC equipment/design has a
harder time shining when you have a poor envelope and/or the lighting
designer treats LPD's as a "budget" they have to use up.  For such reasons,
it's advisable to always consider building performance in holistic fashion
in early/broader discussions.

That's my (simple) take anyway!

~Nick

NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com


-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of RobertWichert
Sent: Wednesday, January 16, 2013 9:24 AM
To: EnergyPro at yahoogroups.com; bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] LEED - What does it take?

I know that LEED is way more than just energy, and energy is way more than
just equipment, but just for a basis, what SEER and EER do people have to
use to get 10% better than ASHRAE 90.1 to qualify for LEED?  I also know
that you don't have to use ASHRAE 90.1, but that is what I am doing.

So, what does it take?

My shot - Residential Apartment, individual DX units, 17 SEER and 13 EER in
California CZ 12 (Mostly cooling).

   Next?


--
Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060 <tel:%2B1%20916%20966%209060> 
FAX +1 916 966 9068 <tel:%2B1%20916%20966%209068> 







===============================================

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-- 
M. Dennis Knight, P.E. 

Founder & CEO

Whole Building Systems, LLC

P.O. Box 1845

Mt. Pleasant, SC 29465

Phone: 843-437-3647

Email: dknight at wholebuildingsystems.com

Website: www.wholebuildingsystems.com

 

 





 

-- 
M. Dennis Knight, P.E.

Founder & CEO

Whole Building Systems, LLC

P.O. Box 1845

Mt. Pleasant, SC 29465

Phone: 843-437-3647

Email: dknight at wholebuildingsystems.com

Website: www.wholebuildingsystems.com

 

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