[Equest-users] pool heating baseline system
Nick Caton
ncaton at smithboucher.com
Wed Jan 26 07:23:21 PST 2011
John and Edward - thanks very much for your input!
Up to this point I've been trying to address the problem with the
assumption the pool is not part of an enclosed/conditioned space. I'm
pretty sure my position below stands strong in that case.
I'd reiterate: I do feel you can make a case either way regarding
whether energy spent heating pool water is or is not a process. Either
you treat this heating energy as a service water heating system, or as a
process load. In the case of an enclosed/conditioned space, you could
use either approach, but either way I agree one should define and assign
the pool's thermal mass and the heating system's incident internal
heating load (with the correct latent/sensible fractions) to the
corresponding space.
If the actual design for an enclosed space containing a heated pool
should have air conditioning (cooling , heating and/or dehumidification)
in addition to pool water heating system, it seems to me intuitive to
model the actual HVAC system(s) in the proposed and the appropriate
Appendix G system in the baseline model (likely using the same baseline
system used elsewhere in the building). The pool's thermal
loads/massing incident on the space would then be present for such
system(s) to react to as required.
Edward: Conditions maintained (cooling setpoints/heating
setpoints/humidity control parameters as they apply) must be maintained
identical in both baseline and proposed models when you're discussing a
conditioned space - you're right on, and you can find support within
Table G3.1 to back you up if needed. The notion to sub-meter the pool
heating loads in a separate run for LEED reporting is only a suggestion
on my part - disregard if you don't feel it's necessary.
Again, I haven't actually completed a pool model under LEED review, but
I think everyone ought to have some flexibility to model pool heating
either as a process load or as a service water heating system. The
"most right" decision would depend on the specific circumstances of the
pool's design, but I think if I were in a reviewer's shoes I'd accept
either approach/interpretation if well-explained & documented.
~Nick
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
-----Original Message-----
From: Eurek, John S NWO [mailto:John.S.Eurek at usace.army.mil]
Sent: Wednesday, January 26, 2011 8:12 AM
To: Mirza Sajjal; Nick Caton; Pasha Korber-Gonzalez
Cc: equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] pool heating baseline system (UNCLASSIFIED)
Classification: UNCLASSIFIED
Caveats: NONE
'Pool heating' conditions the pool space for the comfort of the
occupants.
(Ever jumped into an unheated pool?) So I would say it is not a process
load.
"Energy consumed in support of a manufacturing, industrial, or
commercial
process other than conditioning spaces and maintaining comfort and
amenities
for the occupants of a building."
It would fall under that same arena as water heating for showers.
Classification: UNCLASSIFIED
Caveats: NONE
From: Edward Allen [mailto:eallen at long.com]
Sent: Wednesday, January 26, 2011 1:40 AM
To: Nick Caton; Dahlstrom, Aaron; Mirza Sajjal; Pasha Korber-Gonzalez
Cc: equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] pool heating baseline system
It's unfortunate that I've caught onto this discussion late, as it is
right in the middle of a current tax rebate modeling project I'm working
on.
My query (more of a confirmation really) is how are you all handling the
latent load from the pool? I've input it as a process load, 100%
latent.
How do you account for the thermal mass of the pool water? Latent heat
is handled above. What about sensible effects? I've entered the pool
water in the "Contents" tab covering 80% of the floor area with 500
lb/ft2.
Also, what is the group's read on the space conditions to be maintained
in the proposed vs. budget cases? I've modeled them identical in both:
85 deg F, 55% RH per ASHRAE recommendations. It doesn't show up on any
building meters, so wouldn't be double counted as service water as
discussed below and misc equip.
Finally, what system is appropriate for the budget case model? I've
just let the compliance tool select the system, and it chose PIU - the
same as the none pool zones in the building.
Thanks,
Edward M. Allen, PE, CEM
LONG Energy Solutions
Technology for Better Buildings
775.657.9180 office 720.217.1356 mobile 775.657.9180 fax
eallen at long.com
http://www.long.com <http://www.long.com/>
________________________________
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Nick
Caton
Sent: Tuesday, January 25, 2011 8:38 PM
To: Dahlstrom, Aaron; Mirza Sajjal; Pasha Korber-Gonzalez
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] pool heating baseline system
Well I've given a little extra effort =)... I've flip-flopped a few
times, and now feel confident of the following:
1. This query boils down to this paraphrase: Does Table G3.1.11
(Service Hot-Water Systems) or G3.1.12 (Receptacle and other loads)
apply to pool water heating?
2. Definitions Section 3: service water heating - heating water
for domestic or commercial purposes other than space heating and process
requirements.
3. We can strike out space heating, so we can conclude pool water
heating is either a process energy OR service water heating... it cannot
be both.
4. GRAMMAR LESSON FOR ANSI/ASHRAE/IESNA - WOOHOO!
a. Per the definition Mirza transcribed below, pool heating is
pretty clearly "...maintaining comfort and amenities for the occupants
of a building."
b. So (clearly) pool heating energy simply [IS/IS NOT] a process
energy, and therefore [IS/IS NOT] a process load. Read that whole
definition from both angles, and you can see this definition was not
crafted by an English teacher! This doesn't make anyone's life easier,
but I maintain this definition can be read either way.
5. Where the glossary fails us, we have to look elsewhere.
Fortunately, this seems much more clear: Pool water heating must be a
form of service water heating, otherwise it wouldn't be explicitly
addressed multiples times under Section 7 "SERVICE WATER HEATING."
Clever eh =)?
In conclusion, within the context of "do I model pool energy under the
requirements of Table G3.1.11 or G3.1.12?" The answer is clearly
G3.1.11 because it is a variety of service hot-water system. To extend
the argument, pool water heating is NOT a process energy and so should
NOT be modeled as such (equally in both models), even if it would save
time (bummer!). I might suggest documenting the pool heating
consumptions/demands separately from domestic water heating consumption
in the LEED template.
Table G3.1.11 is agreeably crystal-clear in requiring you to use
straight electric resistance heating for the baseline pool heating
system.
If LEED was an episode of "America's Next Top Model," and the 90.1-2007
steering committee were the judges, heat-pump pool heating strategies
would be rated "Platinum-Sexy."
I might also watch more TV... kinda sad... ^_^
~Nick
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: Dahlstrom, Aaron [mailto:ADahlstrom at in-posse.com]
Sent: Tuesday, January 25, 2011 7:59 PM
To: Mirza Sajjal; Nick Caton; Pasha Korber-Gonzalez
Cc: equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] pool heating baseline system
Mirza -
I agree with your logic about the intent of the standard and its
definition of non-regulated process. This may be a prejudice that
harkens back to LEED v2.1, but if I see a regulation in 90.1 for
efficiency, I assume that ASHRAE intended to "regulate" the energy use
of that category, and thus it falls on the non-process side of things.
While there may be circumstances where "pool heating" might seem more
like a process load (eg freeze protection for an outdoor decorative
fountain in a cold climate?), it seems like the intent of 90.1 was to
regulate pool heating energy usage for a large proportion of typical
pool installations.
I think your question re: how to interpret the wording of G3.1.11 is
important.
On the face of App G, the standard appears to reward heat pump pool
heaters, by allowing them to compare to straight resistance heat in the
baseline.
In my admittedly limited experience, I haven't seen an electric
resistance pool heater, so I share your reservations about making a
false comparison. (then again ...
http://www.little-giant.com/water-heating-products/pool-spa-heaters/elec
tric-pool-spa-heaters.html)
If we can't find help for you on this list, an "unofficial
interpretation" by the 90.1 Standards Committee might be the way to go.
(Maybe Nick could even slip the question in when he's out at the winter
meetings this week ;) ?)
Aaron Dahlstrom , PE, LEED(r) AP
In Posse - A subsidiary of AKF| 1500 Walnut Street, Suite 1414,
Philadelphia, PA 19102
d: 215-282-6753| m: 267-507-5470| In Posse: 215-282-6800| AKF:
215-735-7290
e: ADahlstrom at in-posse.com | in posse web: www.in-posse.com
<http://www.in-posse.com/> | akf web: www.akfgroup.com
<http://www.akfgroup.com/>
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Mirza
Sajjal
Sent: Tuesday, January 25, 2011 7:36 PM
To: Nick Caton; Pasha Korber-Gonzalez
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] pool heating baseline system
Pasha/Nick,
Thanks for the response.
I would assume pool space conditioning and pool water heating are not
process energy (?) as 90.1 defines process energy as:
"Energy consumed in support of a manufacturing, industrial, or
commercial process other than conditioning spaces and maintaining
comfort and amenities for the occupants of a building."
I did notice the baseline efficiency for heat pump pool heaters in table
7, but was trying to figure out if the system types had to be the same
in baseline and proposed since App. G mentions only energy source:
"Where the energy source is electricity, the heating method shall be
electric resistance."
Considering the savings are significant when using electric resistance
pool heating in the baseline, I want to prevent any issues I may
encounter during the LEED review process since the reviewer may have a
different interpretation/opinion.
Mirza
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Nick
Caton
Sent: Tuesday, January 25, 2011 7:05 PM
To: Pasha Korber-Gonzalez; Mirza Sajjal
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] pool heating baseline system
Whether or not it's a process load may come down to semantics (I think
you can make a case either way if you reference the 90.1 glossary terms
- see 'process load' and 'process energy'), but I think it's moot in a
broad sense...
If there weren't significant savings to be credited, then I'd probably
try to call it a process load and make each model identical. That would
be the simplest and most time efficient approach.
However, if there are major savings using heatpumps relative to
"conventional" heating means, then even if it is a "process load" I
would pursue modeling them differently as an exceptional calculation.
Oh, and 90.1 does define a baseline efficiency (COP) for heat pump pool
heating equipment: Take a closer look the table in chapter 7. You
might also review the prescriptive pool requirements for other means to
differentiate the proposed design other than in heating efficiency.
Best of luck!
~Nick
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: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Pasha
Korber-Gonzalez
Sent: Tuesday, January 25, 2011 4:50 PM
To: Mirza Sajjal
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] pool heating baseline system
Isn't the pool heating system considered as a process load for 90.1
since it has no effect on the overall building design? It would be
exactly the same in the baseline as it is for the proposed case.
...just a thought, although I haven't run into this scenario with any of
my sim projects.
Pasha
On Tue, Jan 25, 2011 at 3:19 PM, Mirza Sajjal <ms2995 at gmail.com> wrote:
Can anyone tell me what the baseline pool heating system should be if
the design calls for heat pumps? Per App. G Table G3.1.11 the
requirement is that the energy source be the same, in this case
electricity. Can we model the baseline as electric water heaters or
should the system type (heat pumps) also remain the same in the baseline
since electric resistance pool heating is unconventional? Theres a huge
energy savings difference between the two baselines and was wondering
how others have modeled this in terms of LEED.
Your opinion and insight is much appreciated.
Thanks in advance for any response.
Mirza
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