[Bldg-sim] Right sizing of equipment aka sleeping giant

[Eurek, John S NWO]

My thought process-

I have had a few designs which had meeting rooms which could hold a large
number of people.  If I were to size the equipment for the max number of
people on the hottest day the equipment size would be a few tons larger.

Example.  A high school youth room in a church on the third (top) floor with
a max occupancy of 30 people.

My conclusion.  If 30 high school kids try to meet in that room at 4:00 p.m.
in the middle of summer, that room will get warm.... They should find another
room.  The sanctuary isn't likely going to be in use at 4:00.

There have been other meeting rooms I have used this line of thought. So far
I have only applied it to meeting rooms.  Simple, if you try to pack a
meeting room with people on a hottest day at the hottest part of the day, it
may get hot.  It isn't a poor design, it is using the 'art' of engineering.

Best advice.  Talk to the owner.  There is a lot of equipment sizing
reduction opportunity by finding the 'worse practical' design conditions as
opposed to the typical 'worst possible' conditions.

Two other examples of this which another designer shared with me.  
1. Schools don't usual hold classes in the summer.  Find the peak during
school months, not in July.  The design will typically be large enough to
handle summer school.  And this condition can be modeled to check.
2. Christmas and Easter are not in the summer.  And services are usually in
the morning.  A church typically has no need for a system to be designed for
100% at 4 p.m. in the summer.

(This doesn't help for LEED since you must use the same schedules as the
baseline, but it helps in actual energy savings.  This could actually hurt
you in LEED with UNMET hours if you don't modify your schedule to match your
assumptions.)

*I am really enjoying this sharing of information.  Thank you all.*

John Eurek
LEED AP
Mechanicl P.E. in waiting (still 3 weeks to see if I passed)

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Acker, Brad
Sent: Tuesday, May 25, 2010 3:26 PM
To: eQUEST Users List; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Right sizing of equipment aka sleeping giant

I think this is a wonderful time to be in the HVAC industry. New tools are
changing the outdated, over simplified tools and methods used in the past
(and present). I would like to make one comment on the below message. The
sentence "Building occupants are intolerant of too hot and too cold."  This
is one good example of the changing attitudes in the building industry.
Resent research suggest that this sentence should really read " Building
occupants with no control over their environment are intolerant to too hot or
too cold".  When occupants know they can control their environment (maybe
with a window) they will dress accordingly and expand their comfort zone. 

On a "right sizing" note, I do believe if owners would like to get aggressive
and truly right size equipment they will also need to shoulder the possible
risks, i.e. 10 or 20 hours out of the year you may not be able to keep  your
cooling set point. Its energy modeling that will quantity these risks and
size these systems, not a side ruler and a design day (hour).

 

This exchange has been a nice change of pace from locating weather files.
It's very interesting to learn other current points of view in our industry,

 

Best Regards,

 

Brad Acker, P.E.

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Monday, May 24, 2010 12:07 PM
To: eQUEST Users List; bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Right sizing of equipment aka sleeping giant

 

All,

Should always be the goal but it is soooo hard to define. I have worked on
tiny commercial buildings as well as huge commercial buildings. All types.
Right sizing is always my goal and as far as I know is always the goal of the
ME's. It was mine when I did HVAC design work. Building occupants are
intolerant of too hot and too cold. And, in a building of any size with more
than one person in it you will find disagreement about whether it is too hot
or too cold at least some of the time. So what do you do? Especially if you
are just the hapless, overworked, under paid energy modeler? You can see my
project list if you want to. If you listen closely you will hear whatever
opinion you want to hear about me and my work. Thank god for VFDs, VRVs and
EC motors, eh?

--
Carol Gardner PE