[Bldg-sim] ventilation only & LEED

[Jorge Torres-Coto]

Christian,

 

For good or bad, I have ended up modeling many Warehouse Distribution
Centers, which in essence have a very small front office and a very large
warehouse that is only ventilated (by code).  I have had to argue with LEED
reviewers this point, fortunately successfully.  The warehouse area is by
definition "unconditioned space", just like Nick states.  Though you still
have to model an HVAC system per ASHRAE, but spreading the setpoints
basically to outside air design conditions.  The reviews I have had have
made it through this way.  By doing this with the setpoints, you will not
have any unmet hours.  But you are still providing the right amount of
ventilation air per 62.1 and the right power for all the fans.  The office
is a totally different story, which you pretty much know the answer to.

 

I have had the comments go both way on the following.  Since the Warehouse
is not conditioned I had one reviewer tell me to change the Baseline HVAC
system to packaged units due to the fact that the only conditioned space was
a tiny 10,000 sq.ft. space.  Other reveiwers have left me keep my standard
ASHRAE System 8 baseline with the modifications mentioned above for the
warehouse area. (I usually utilize two air handlers: one for warehouse and
one for offices).

 

Jorge E. Torres Coto   

4830 Viewridge Ave.

San Diego, CA 92123

p              858.751.0933

f               858.751.0937

c              858.688.6088



  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Wednesday, June 01, 2011 7:34 AM
To: christian stalberg; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] ventilation only & LEED

 

Hi Christian,

 

A LEED reviewer brought up this issue for a heated/ventilated-only garage
space recently.  Owner did not want a cooling system beyond ventilation, and
one was not designed.  Ultimately, our reviewer cited TG3.1.1.b / G3.1.10
directly, and I conceded to model baseline-esque cooling systems in both
models.  

 

I'm not sure section 2.2 is a great defense as it states the standard
doesn't apply to *envelopes* without a heating/cooling system. not
ventilation systems (2.2.b.).  A better defense is if your warehouse is by
90.1 glossary terms an unconditioned space, by virtue of not meeting any of
the three conditioned space definitions.  In that case, I think you could
flatly reject TG3.1.1.b as "not applicable" if it were brought up.  In our
garage space above, this wasn't an option as it was definitely a heated
space (see glossary for underlined terms).

 

I'd agree modeling both models with ventilation only is the intuitive thing
to do in the context of a validation (LEED) model.  The intent of this
language however, if I'm not mistaken, is to discourage/punish design
decisions to omit heating and/or cooling systems entirely to save energy.
Never mind that's actually a very effective strategy, under the right
circumstances and in moderation.  I've got some contrarian opinions in this
department, so I'll keep my mouth shut =).

 

~Nick

cid:489575314 at 22072009-0ABB

 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of christian
stalberg
Sent: Wednesday, June 01, 2011 5:32 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] ventilation only & LEED

 

The warehouse section of our facility in El Salvador is to be ventilated
only.  The textile section of the same building will be cooled and humidity
will be controlled. Other areas such as offices and cafeteria will be
cooled. There is no heating load in El Salvador. I reviewed inquiry 5088
(copy below) which would suggest the warehouse should be modeled with air
conditioning in both the base case and the proposed case even though no
cooling will be provided.  Our building is a little different than the
building in inquiry 5088 in that it has no heating load.  Therefore by the
90.1 standard, the standard does not apply (section 2.2) and it is an
unconditioned space.  We feel the ventilated section of our building should
be rated based on energy savings of standard ventilation equipment versus
the proposed high efficiency fans and louvers that we are providing for
ventilation.  We would like to proceed with the ventilated enclosures being
included in the model without heating or cooling.  Please advise.

 

 


Inquiry Number: 

5088 


MPR/Prerequisite/Credit: 

EAc1: Optimize Energy Performance 


Posting date: 

11/27/2007 

 

   

It is not acceptable to allow spaces to exceed the unmet load hour
requirements of the ASHRAE 90.1-2004 Appendix G methodology. This is a
similar situation to naturally ventilated spaces, which are required to
include cooling systems to meet space loads in the proposed case even if the
actual building will contain no cooling. Building owners may always choose
to turn off HVAC systems, or not have them installed at all to conserve
energy, but the ASHRAE modeling protocol assumes that cooling systems will
be installed and run with sufficient capacity to meet space loads. The
applicant may use a set-point of 80 degrees Fahrenheit for the maintenance
bays, but cooling system capacity must be increased until the requirements
of ASHRAE 90.1-2004 section G3.1.2.2 are met. The project may still receive
credit for using an efficient cooling system as compared to the ASHRAE
baseline cooling system.

 

    Inquiry [  <https://www.usgbc.org/images/LI/Minus.GIF> ] 


 

Our project is located in Las Vegas and consists of a combination of office
spaces and maintenance bays for earth-moving equipment. The owner is a large
agency that sells, rents and repairs such equipment; these repairs are done
both inside and outside the building envelope. The maintenance bays are
occupied by mechanics and will be conditioned with evaporative coolers and
gas furnace heat, the system supplies 100% outside air. This cooling system
provides conditioning of the spaces but is not able to meet all peak loads
for a climate such as Las Vegas even when these spaces are modeled with
higher setpoint at 80 degrees. In reality, if the maintenance bays go above
the temperature setpoints, the mechanics will continue work in the warmer
conditions or take a break. This is not difficult for maintenance bays,
where some of the work will also done outdoors with no conditioning at all.
The owner does not want to fully condition the maintenance bays with the
intention of achieving high levels of energy efficiency. We propose the
following modeling approach for EA Credit 1. -Baseline model will have a
mechanical system based on Table G3.1.1A of Appendix G with 80 degree
temperature setpoint for the maintenance bays. -Proposed Design model will
have the system as designed in the building that provides partial
conditioning with the same 80 degree temperature setpoint. We will not model
additional compressor cooling for hours where the system is not able to meet
loads. This approach will result in exceeding the difference in the unmet
load hours beyond 50 as required by Appendix G. However, this is a conscious
decision by the owner who wants to maximize energy efficiency by providing
limited conditioning through evaporative cooling for the maintenance bays,
and allow the temperatures to float higher during peak conditions. We feel
that this approach appropriately captures the intent of the design, and
gives credit to the energy efficiency measures being taken. It also provides
a way for demonstrating the value of an energy efficient approach to the
community in Las Vegas where compressor cooling is increasingly used, often
indiscriminately; this is a desert climate and a different approach to
comfort and conditioning is possible. Is this approach acceptable? If not,
can you advise us on an alternative approach that addresses the desire of
the owner to demonstrate high levels of energy efficiency for using such a
system?

 

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