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Can you please help with my homework? kool 07-13-2007
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Posted by kool on July 14, 2007, 12:32 am

> wrote:
>
>>
>>> wrote:
>>>
>>>> I have been asked to arrange a quote to cool only an existing building
>>>>(arena with bowl type seating) for summer use as now the conditions are
>>>>unbearable during events.
>>>>
>>>>I am thinking that 4 BIG units might be the way to go,one in each
>>>>corner,
>>>>probably splits.
>>>>
>>>>I can't seem to find a design condition chart from ashrae or anyone else
>>>>on
>>>>google. It is a fairly moderate year round climate here, from memory I
>>>>think
>>>>we're talking around 80f summer but it hit the mid 90's two days
>>>>ago.Just
>>>>the people load would be 125 tons and 45,000 cfm o/air required..As this
>>>>will be a major financial investment, I need to do it right the first
>>>>time
>>>>and any input on design considerations would be appreciated. Thanks.
>>>>
>>>>Victoria B.C.
>>>>
>>>> Indoor Conditions;24 C/75 F @ 50% RH
>>>>
>>>>Design Conditions; ?
>>>>
>>>> Occupancy load; 3000x500=1,500,000 btu
>>>>
>>>> Square footage;280'x165'= 46,200
>>>>
>>>> Cubic footage; 280'x165'= 46,200x48=2,217,600
>>>>
>>>
>>> Based on the information given ;
>>>
>>> You've never done this kind of job before
>>
>>right
>>
>>> You don't feel at all confident now
>>
>>wrong
>>
>>> You don't know how to provide complete information
>>
>>wrong
>>>
>>> Therefore, you don't understand what to look for in this
>>> specialized kind of application.
>>
>>wrong
>>
>> You haven't mentioned solar load,
>>
>>true (although most events are in the evenings)
>
> There's some of the incomplete information I mentioned. Plus
> building load other than occupancy gain, IOW standard load calcs.
>

Yes it will take a while to get the info together.

>>
>>> pre-cooling, indoor design temps ( which at not going to be 'standard
>>> indoor design' like for a house )
>>
>>75F @50%RH (see original post)
>
> That is a VERY aggressive ( cold ) target for public events
> where people are coming in from the warmer outside. IMO.

You could be right about that as I just pulled those numbers out of my ass.


> Pre-cooling will be a LARGE factor in your design, if you do
> it right. Off the top of my head, you should be able to plan on maybe
> 10 degree rise during events, which means you can pre-cool to 70,
> expect it to rise to 80 during a 4 hour event, which means you can do
> the pre-cooling in 4- 8 + unoccupied hours, which means your max size
> is much smaller.

I had not even considered pre-cooling as an option.That got me thinking
about firing up the idle refrigeration plant (195 HP) for a few hours and
cool the brine in the 17000sq.ft. floor to just above the dewpoint.That
should take the edge off the heatload.I guess the dewpoint would change
pretty quick when the 3000 bodys arrive.

>>other internal loads ( lights, which
>>> are massive, concessionary equipment ) etc, outdoor air requirement (
>>> which is a MASSIVE part of your load )
>>
>>45,000cfm (see original post again)
>
> OK, you did say that.
>
>>Hell, I've only spent 15 minutes on this so far.
>
> Hell, so have I :-)
>
>>
>>, smoke / fire dampers and
>>> control, etc etc etc
>>
>>Of course, all equipment will be compliant to all codes as this is a
>>public
>>building
>
> My point being, smoke exhaust CFM specs will be a guiding
> factor in fan selection, as well as SOO.

Not clear on this point. Right now we have 1-Engineered Air Dessicant
dehumidifier capable of 100% O/A damper position. Also a second air handler
with a hot water coil with the same damper setup and three exhaust fans on
the ridge of the building.These are controlled by the Delta Igraph DDC
system to maintain temperature, humidity,CO levels and a slight negative
building pressure. I will investigate their CFM capabilities next week.Any
additional outside air will have to be considered.What is SOO?


>>> Which add up to :
>>>
>>> You lack the knowledge to handle this job by yourself, and you
>>> need to tell your boss you need more experienced help.
>>
>>Paul, I only asked if there are design condition tables available on the
>>net. This is all very preliminary.I also asked for any input as I will be
>>soliciting quotes but we need to tell contracters what we would like them
>>to
>
>
> Well, I don't know what kind of 'design condition tables'
> someone in the field would need.
>
> The BIN tables for your location can be found anywhere, you
> indoor design target is a decision to be made, and eveything else will
> be specific to your structure. You're ~ 24 winter design, 75 summer
> design there.
>
>
http://www.bcpassport.com/vancouver-vital-information/vancouver-climate-tempurature.aspx

Thanks, I didn't use the word BIN but I did check an old SAM manual and
found 85db 68wb cooling and 15 db heating. I guess we have warmer winters
and cooler summers now.
>
> Actually, it looks like you could just open a window :-)

Yea, it would be perfect if all those people didn't show up.

> Seriously, though look intently at massive use of OA, instead
> of purely contained conditioned air, in that location. It looks like
> you could largely get by with a LOT less mechanical than you would
> need elsewhere if you keep your exchanges up.
>
>>quote on. As far as input from you, I have read your resume and I know you
>>can do better than that if you want to.


> Yeh, and I could get paid more, too :-)
>
If you lived closer I would hire you as a consultant but the travel time
would kill us.

> --
> Click here every day to feed an animal that needs you today !!!
> http://www.theanimalrescuesite.com/
>
> Paul ( pjm @ pobox . com ) - remove spaces to email me
> 'Some days, it's just not worth chewing through the restraints.'
> 'With sufficient thrust, pigs fly just fine.'
> HVAC/R program for Palm PDA's
> Free demo now available online http://pmilligan.net/palm/

Thanks Paul, I do appreciate the advice.I knew you had it to offer.Lots of
good points to think about for the weekend.



Posted by Jeffrey Lebowski on July 14, 2007, 12:40 am

>
> > wrote:
> >
> >>
> >>> wrote:
> >>>
> >>>> I have been asked to arrange a quote to cool only an existing
building
> >>>>(arena with bowl type seating) for summer use as now the conditions
are
> >>>>unbearable during events.
> >>>>
> >>>>I am thinking that 4 BIG units might be the way to go,one in each
> >>>>corner,
> >>>>probably splits.
> >>>>
> >>>>I can't seem to find a design condition chart from ashrae or anyone
else
> >>>>on
> >>>>google. It is a fairly moderate year round climate here, from memory I
> >>>>think
> >>>>we're talking around 80f summer but it hit the mid 90's two days
> >>>>ago.Just
> >>>>the people load would be 125 tons and 45,000 cfm o/air required..As
this
> >>>>will be a major financial investment, I need to do it right the first
> >>>>time
> >>>>and any input on design considerations would be appreciated. Thanks.
> >>>>
> >>>>Victoria B.C.
> >>>>
> >>>> Indoor Conditions;24 C/75 F @ 50% RH
> >>>>
> >>>>Design Conditions; ?
> >>>>
> >>>> Occupancy load; 3000x500=1,500,000 btu
> >>>>
> >>>> Square footage;280'x165'= 46,200
> >>>>
> >>>> Cubic footage; 280'x165'= 46,200x48=2,217,600
> >>>>
> >>>
> >>> Based on the information given ;
> >>>
> >>> You've never done this kind of job before
> >>
> >>right
> >>
> >>> You don't feel at all confident now
> >>
> >>wrong
> >>
> >>> You don't know how to provide complete information
> >>
> >>wrong
> >>>
> >>> Therefore, you don't understand what to look for in this
> >>> specialized kind of application.
> >>
> >>wrong
> >>
> >> You haven't mentioned solar load,
> >>
> >>true (although most events are in the evenings)
> >
> > There's some of the incomplete information I mentioned. Plus
> > building load other than occupancy gain, IOW standard load calcs.
> >
>
> Yes it will take a while to get the info together.
>
> >>
> >>> pre-cooling, indoor design temps ( which at not going to be 'standard
> >>> indoor design' like for a house )
> >>
> >>75F @50%RH (see original post)
> >
> > That is a VERY aggressive ( cold ) target for public events
> > where people are coming in from the warmer outside. IMO.
>
> You could be right about that as I just pulled those numbers out of my
ass.
>
>
> > Pre-cooling will be a LARGE factor in your design, if you do
> > it right. Off the top of my head, you should be able to plan on maybe
> > 10 degree rise during events, which means you can pre-cool to 70,
> > expect it to rise to 80 during a 4 hour event, which means you can do
> > the pre-cooling in 4- 8 + unoccupied hours, which means your max size
> > is much smaller.
>
> I had not even considered pre-cooling as an option.That got me thinking
> about firing up the idle refrigeration plant (195 HP) for a few hours and
> cool the brine in the 17000sq.ft. floor to just above the dewpoint.That
> should take the edge off the heatload.I guess the dewpoint would change
> pretty quick when the 3000 bodys arrive.
>
> >>other internal loads ( lights, which
> >>> are massive, concessionary equipment ) etc, outdoor air requirement (
> >>> which is a MASSIVE part of your load )
> >>
> >>45,000cfm (see original post again)
> >
> > OK, you did say that.
> >
> >>Hell, I've only spent 15 minutes on this so far.
> >
> > Hell, so have I :-)
> >
> >>
> >>, smoke / fire dampers and
> >>> control, etc etc etc
> >>
> >>Of course, all equipment will be compliant to all codes as this is a
> >>public
> >>building
> >
> > My point being, smoke exhaust CFM specs will be a guiding
> > factor in fan selection, as well as SOO.
>
> Not clear on this point. Right now we have 1-Engineered Air Dessicant
> dehumidifier capable of 100% O/A damper position. Also a second air
handler
> with a hot water coil with the same damper setup and three exhaust fans on
> the ridge of the building.These are controlled by the Delta Igraph DDC
> system to maintain temperature, humidity,CO levels and a slight negative
> building pressure. I will investigate their CFM capabilities next week.Any
> additional outside air will have to be considered.What is SOO?
>
>
> >>> Which add up to :
> >>>
> >>> You lack the knowledge to handle this job by yourself, and you
> >>> need to tell your boss you need more experienced help.
> >>
> >>Paul, I only asked if there are design condition tables available on the
> >>net. This is all very preliminary.I also asked for any input as I will
be
> >>soliciting quotes but we need to tell contracters what we would like
them
> >>to
> >
> >
> > Well, I don't know what kind of 'design condition tables'
> > someone in the field would need.
> >
> > The BIN tables for your location can be found anywhere, you
> > indoor design target is a decision to be made, and eveything else will
> > be specific to your structure. You're ~ 24 winter design, 75 summer
> > design there.
> >
> >
http://www.bcpassport.com/vancouver-vital-information/vancouver-climate-temp
urature.aspx
>
> Thanks, I didn't use the word BIN but I did check an old SAM manual and
> found 85db 68wb cooling and 15 db heating. I guess we have warmer winters
> and cooler summers now.
> >
> > Actually, it looks like you could just open a window :-)
>
> Yea, it would be perfect if all those people didn't show up.
>
> > Seriously, though look intently at massive use of OA, instead
> > of purely contained conditioned air, in that location. It looks like
> > you could largely get by with a LOT less mechanical than you would
> > need elsewhere if you keep your exchanges up.
> >
> >>quote on. As far as input from you, I have read your resume and I know
you
> >>can do better than that if you want to.
>
>
> > Yeh, and I could get paid more, too :-)
> >
> If you lived closer I would hire you as a consultant but the travel time
> would kill us.
>
> > --
> > Click here every day to feed an animal that needs you today !!!
> > http://www.theanimalrescuesite.com/
> >
> > Paul ( pjm @ pobox . com ) - remove spaces to email me
> > 'Some days, it's just not worth chewing through the restraints.'
> > 'With sufficient thrust, pigs fly just fine.'
> > HVAC/R program for Palm PDA's
> > Free demo now available online http://pmilligan.net/palm/
>
> Thanks Paul, I do appreciate the advice.I knew you had it to offer.Lots of
> good points to think about for the weekend.
>

Suggest you two get a room.

--




Posted by on July 14, 2007, 10:12 am
wrote:

>

It is a fairly moderate year round climate here, from memory I
>>>>think
>>>>we're talking around 80f summer but it hit the mid 90's two days
>>>>ago.Just
>>>>the people load would be 125 tons and 45,000 cfm o/air required..As this
>>>>will be a major financial investment, I need to do it right the first
>>>>time

        Then that 75 OD design temp would be too low, but you don't
need to design for 95, either. WHen it's 95 outside, people don't
expect it to be 75 inside at a public sporting event or concert etc,
as if it were an office or home. And you don't have to be able to
hold +/- 1 or 2 degrees, like you would for a residential system.

>>>
>>>75F @50%RH (see original post)
>>
>> That is a VERY aggressive ( cold ) target for public events
>> where people are coming in from the warmer outside. IMO.
>
>You could be right about that as I just pulled those numbers out of my ass.

        Eeewwww !!!

>> Pre-cooling will be a LARGE factor in your design, if you do
>> it right. Off the top of my head, you should be able to plan on maybe
>> 10 degree rise during events, which means you can pre-cool to 70,
>> expect it to rise to 80 during a 4 hour event, which means you can do
>> the pre-cooling in 4- 8 + unoccupied hours, which means your max size
>> is much smaller.
>
>I had not even considered pre-cooling as an option.That got me thinking
>about firing up the idle refrigeration plant (195 HP) for a few hours and
>cool the brine in the 17000sq.ft. floor to just above the dewpoint.That
>should take the edge off the heatload.I guess the dewpoint would change
>pretty quick when the 3000 bodys arrive.

        This is the kind of thing I was talking about when I said
'you've never done this kind of job before'.

        By your description, you're going to have a certain peak load
that appears suddenly, stays a short time, and goes away. IF you can
spread out the time period that you handle it in ( pre-cooling,
thermal banking etc ), then your equipment size goes down.

>>>, smoke / fire dampers and
>>>> control, etc etc etc
>>>
>>>Of course, all equipment will be compliant to all codes as this is a
>>>public
>>>building
>>
>> My point being, smoke exhaust CFM specs will be a guiding
>> factor in fan selection, as well as SOO.

>Not clear on this point. Right now we have 1-Engineered Air Dessicant
>dehumidifier capable of 100% O/A damper position. Also a second air handler
>with a hot water coil with the same damper setup and three exhaust fans on
>the ridge of the building.These are controlled by the Delta Igraph DDC
>system to maintain temperature, humidity,CO levels and a slight negative
>building pressure. I will investigate their CFM capabilities next week.Any
>additional outside air will have to be considered.What is SOO?


        Sequence Of Operation. In reference to, specifically, life
safety system shutdown and smoke purge. Damper fail-safes etc.

        If it's like the States, the Fire Marshall will have some very
serious specs for any entertainment venue regarding smoke purge
capacity and fail-safe. That will affect the duct / damper / fan
design a great deal, and you want any plans approved and stamped by
them first. They can shut you down in a heartbeat if they say you're
not meeting safety spec.

>Thanks, I didn't use the word BIN but I did check an old SAM manual and
>found 85db 68wb cooling and 15 db heating. I guess we have warmer winters
>and cooler summers now.

        Your numbers sound like a more reasonable target to me. It
might not get there often, but you don't want a building that 'just
can't keep up on hot days'.


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

Posted by on July 14, 2007, 10:35 am
On Sat, 14 Jul 2007 10:12:40 -0400, .p.jm@see_my_sig_for_address.com
wrote:

>>I had not even considered pre-cooling as an option.That got me thinking
>>about firing up the idle refrigeration plant (195 HP) for a few hours and
>>cool the brine in the 17000sq.ft. floor to just above the dewpoint.That
>>should take the edge off the heatload.I guess the dewpoint would change
>>pretty quick when the 3000 bodys arrive.

        If you could do that and also during that pre-cool take a
brine loop to an air handler to be pre-drying out the space ( again,
control of SHR will be critical ), you would be doing a really good
thing.

        In fact, if the OA during events also ran through that same
AHU, getting dried out, while the floor continues to be kept cool,
that might even be your entire sytem right there. One new AHU and
some piping and controls.

        Both DB and WB can be allowed to rise during the events, as
long as they start out low enough.


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

Posted by on July 14, 2007, 10:28 am
wrote:

>

>> Pre-cooling will be a LARGE factor in your design, if you do
>> it right. Off the top of my head, you should be able to plan on maybe
>> 10 degree rise during events, which means you can pre-cool to 70,
>> expect it to rise to 80 during a 4 hour event, which means you can do
>> the pre-cooling in 4- 8 + unoccupied hours, which means your max size
>> is much smaller.
>
>I had not even considered pre-cooling as an option.That got me thinking
>about firing up the idle refrigeration plant (195 HP) for a few hours and

        You might not even need to add any more cooling, if you do it
right.

>cool the brine in the 17000sq.ft. floor to just above the dewpoint.That
>should take the edge off the heatload.I guess the dewpoint would change
>pretty quick when the 3000 bodys arrive.

        You're going to need to go far below dewpoint from the system,
of course not in terms of the building mass itself, but system output.

        Humidity is going to be the largest portion of your total
load, both from the large OA need, plus persperation from the crowd.
Anything you can do to lower the humidity, will lower your need for
making it cooler.

        You could look at using the existing plant, with thermal
banking perhaps, into a purpose-specific dehumidifer, to help pre-dry
both the space, and the OA intake before it gets into the space.

        Also, thermal banking / ice banking could help 'spread out the
load' as previously.

        A space at 80 F, 60 RH is uncomfortable, damp, clammy. At 80
F 30 RH, it is very comfortable. You want to look very closely at
the two types of heat you have to deal with ( sensible and latent ),
and when they occur, in what proportions.

        You need to look at the scenario of a rainy evening, when
you're bringing in all that OA at 90 % RH - you WILL be amazed what
happens to your loads ! If you just dump that air inside, it will be
miserable in there, and you'll have mold problems next week. If you
pre-dry it first ( either mechanically, or using desiccant, etc ) as
opposed to pre COOLING it, you avoid both problems.

        You need to consider things like runaround loops in both the
air stream and the cooling fluid, with dampers / valves / control
system / etc that can in effect look at sensible load separately form
latent load, and tune to each one as needed. IOW, you need to be able
to control the SHR of the system over a wide range - one simple
setpoint won't really get it, IMO. You need to be looking at 3 things
- DB, WB, and ( the combination of them which is ) enthalpy.




--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

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