[Bldg-sim] Spam:Re: Process Loads?

Marcus Sheffer sheffer at energyopportunities.com
Thu Feb 5 12:06:16 PST 2009


Yes just quantify the non-regulated or process loads in the model.  The
purpose behind the 25% was to try and make sure that folks were modeling
everything in the building which affects total energy use.

 

Marcus

 

From: Arvinder Dang [mailto:Arvinder.Dang at som.com] 
Sent: Thursday, February 05, 2009 12:29 PM
To: Marcus Sheffer; bldg-sim at onebuilding.org
Subject: RE: [Bldg-sim] Spam:Re: Process Loads?

 

Marcus,

 

Hope you’re doing well. A quick question as a follow up.

 

I have a campus building that is using district chilled water and steam –
and the energy modeling is based on “Required Treatment of District Thermal
Energy in LEED NC 2.2 and LEED for Schools“. The project is seeking only 2
points and the model only includes downstream equipment keeping the district
heating and cooling cost neutral in both the base case and the design case.

 

The cost of steam is around $44.2 per Mlb of Steam, cost of chilled water
$0.18 while that of electricity only $0.09 base don campus rates.  Since the
cost of steam and chilled water is way higher than that of electricity,
there is no way that process energy cost which includes equipment,
elevators, etc equates to 25%. Cost of space heating and cooling constitutes
a bigger fraction compared to lighting, equipment, pumps and all others end
uses that use the electric rate.

 

Would a narrative explaining the same justify why the minimum 25%
requirement cannot be held for district heating and cooling systems that
model only downstream equipment and are kept cost neutral due to the
differential in the rate structure.

 

Thanks

 

 

ARVINDER DANG, LEED® AP

SUSTAINABILITY SPECIALIST   

 

SKIDMORE, OWINGS & MERRILL LLP 

224 SOUTH MICHIGAN

CHICAGO, IL 60604 

T: 312.360.4633  F: 312.360.4910 

ARVINDER.DANG at SOM.COM

 

 

SOM

 

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From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Marcus Sheffer
Sent: Thursday, February 05, 2009 10:49 AM
To: bldg-sim at onebuilding.org
Subject: Re: [Bldg-sim] Spam:Re: Process Loads?

 

The word “default” is unfortunate; the credit language should read “at
least”.  If your project is under 25% simply submit justification for why
you are under 25%.  The best way to do that is with a table showing the
assumed plug loads or other process loads in the facility.

 

So if you are over 25% no worries; if you are under justify why you are
under.  Don’t add process loads until you reach precisely 25% as some
projects submitting for LEED have done.

 

Regarding facilities with very high process loads pursuing LEED
certification, James is correct that this poses a major problem which the
USGBC will hopefully address this year.

 

Marcus Sheffer, Vice-Chair USGBC EA TAG

Energy Opportunities, Inc/a 7group Company

1200 E Camping Area Road, Wellsville, PA  17365

717-292-2636,  <mailto:sheffer at sevengroup.com> sheffer at sevengroup.com

www.sevengroup.com

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of James Hess
Sent: Wednesday, February 04, 2009 10:11 PM
To: Demba Ndiaye; Anis Ben Ayed; 
Cc: Caleb Brantley
Subject: Re: [Bldg-sim] Spam:Re: Process Loads?

 

FYI 
 our take on this issue is to document the inputs that make up the misc
equipment.  In many cases, we find that misc equipment, or “process loads”
come nowhere close to 25% of total costs.

 

For example, we are currently working on a library LEED project.  We have
very good estimates for the number of computers going into the facility, and
have estimates for students with notebook computers, printer/copiers,
breakroom equipment (refrigerator, coffee pot, etc.), etc.  You can get
energy estimates for all that stuff from EnergyStar’s website (they have
lots of good data), or take your own measurements of equipment over time
like I have ( using simple inexpensive equipment such as the “KillaWatt”
plug in 120V plug load measurement device).

 

Anyway, we document it and add all that up à comes to ~ 0.3 watts/SF, add a
schedule into our energy simulation program, and we come nowhere close to
25% of total energy costs.

 

What would we do at that point?  We have good wattage inputs based on sound
and reasonable data.  For example, a typical desktop computer will use ~ 65
watts on average.  A 22” flat panel LCD monitor will use ~ 45 watts.  So, do
you throw all those numbers out and arbitrarily increase the “watts/SF”
values until process loads = 25%?

 

Our interpretation is no.

 

Based on the following from LEED NC 2.2

 

 

 

We interpret this as we can use less than 25% as long as we document, so we
document.  We document our assumptions for process loads anyway so if it
comes out less, we’re covered.

 

We did have a project that was a flight simulator building for the US Air
Force.  The simulator equipment used a ton of energy à energy costs > 75% of
total building energy costs.  That blew the LEED savings out of the water.
Even if you assign the same load to the baseline, mathematically it’s very
difficult to achieve overall building energy savings of  14% if 75% of
energy à you can’t do anything about.  J.  In fact, we could not.

 

Just some food for thought on how we approach this area.

 

Hope this helps.

 

Regards,

 

James

 

 

James A.  Hess, PE, CEM

Energy Engineer

TME, Inc.

Little Rock, AR

ph   501-666-6776

cell  501-351-4667

jhess at tmecorp.com <mailto:email at tmecorp.com> 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Demba Ndiaye
Sent: Wednesday, February 04, 2009 5:57 PM
To: Anis Ben Ayed; bldg-sim at onebuilding.org
Subject: Spam:Re: [Bldg-sim] Process Loads?

 

The process energy cost should compose at least 25% of the total energy
cost.

 

And yes, if you have a total cost of $1,333 then the process energy should
be >= $333.

 

_____________

Demba Ndiaye

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Anis Ben Ayed
Sent: Wednesday, February 04, 2009 6:33 PM
To: bldg-sim at onebuilding.org
Subject: [Bldg-sim] Process Loads?

 

Hi All,

 

According to the LEED NC v2.2 user manual, the default process energy cost
is 25% of the total energy cost for the baseline building. 

 

Example:

The total energy cost for a baseline building is T = (X + Process loads) 

Let’s assume that X = $1000.00 = 75% * T

 

To find the energy cost for a baseline building, we solve for T

Therefore T = $ 1000.00 / 75% = $ 1333.33

and the Process loads’ cost = 25 % * $ 1333.33 = $ 333.33

This is how I understand the 25% process load calculation.

 

Can someone please confirm this approach? 

 

Thank you,

 

Anis 

 

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