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'[OT] Air-con advice wanted'
2012\01\31@165852 by IVP

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Hi all,

a friend has recently moved business premises and asked me, after
complaining how hot it's been lately and probably how cold it might
get in winter, about air conditioning

The floor space is approx 1000 sq metres (27,000 sq ft) and the
ceiling height is 5m (16ft). No large windows, front glass door and
roller door at the rear. Uninsulated ceiling (basically it's a masonry
building with a tin roof with 4 plastic sheeting skylights). If you want
to see the building on Google maps, 2 Akepiro St, Eden Terrace,
Auckland

Using a variety of on-line calculators gets a result 80 - 400kW (!!)
or, confusingly, BTU/h units. The wide range of results was no help
at all

Local suppliers' units advertised as "commercial" are typically 7.5kW

In a shop I visited yesterday, approx 1000 sq m x 3m ceiling, which is
comfortably cool, they have two ceiling units about 600mm square.
Unfortunately the rating isn't known by the shop manager (he just sets
the temperature and wasn't willing to do any climbing. pffft, whatever
happened to 'service' ? ;)) )

With your personal experience, what would you suggest for a unit
that would keep a volume like this at say 18-20 in summer (25C
outdoors) and maybe a little lower in winter (10C outdoors)

TIA

Jo

2012\01\31@182238 by Tamas Rudnai

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Hi Joe,

Aircon can be very tricky, I am not sure if you can do a calculation based
only on few parameters. People and machines are generating heat, plus how
much is the air temperature outside might not the most relevant parameter
either. Obviously your building is exposed to the sun at some extent even
if you have other floors above your office, and that can generate a much
higher temperature inside then you have outside -- you can feel this
phenomena easier in a car when you jump into your car at a sunny summer
time and it is over 60C while outside air temperature is only 25C.

Also there are three other issues with aircon, condensation, draft and
temperature distribution. With this latter one in a wrong designed aircon
system you can feel that one side or part of the room has higher/lower
temperature than the other. Draft occurs when the airflow / ventilation was
not designed properly -- which can also cause problems in the temperature
distribution differences. With the condensation you need to control the
humidity of the air as well, not just the temperature -- that also changes
how we feel of the temperature which can be different than the real values
you read on the thermometer.

As air conditioning affects health I would suggest you to consult to an
expert on this and let him to design a proper system so you can avoid your
colleagues complaining about sneezing and pain in the back etc causing by a
wrong aircon.

Tamas



On 31 January 2012 21:58, IVP <spam_OUTjoecolquittTakeThisOuTspamclear.net.nz> wrote:

{Quote hidden}

>


'[OT] Air-con advice wanted'
2012\02\01@085825 by Howard Winter
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Joe,

I'm assuming you're talking about the building at the corner of Charles St. and Akepiro St. on the West side of the latter?  It seems to have 4 long, narrow rooflights, but it doesn't look like 1,000m^2, but looks could be deceptive.  Sadly, Google decided not to send their camera car down that way, or even past the end of Charles St. so we can't see the building other than from overhead.

Well Job 1 is to get that roof insulated!  Solar energy can contribute up to 1kW per square metre on a good day, but even allowing for the angle, reflection and other losses you may find that tin roof is being hit with up to half a megawatt.  It makes no sense to let that heat in and then pay good money to get it out again.

If he doesn't need 5m of height, a false ceiling will help too, as it will tend to keep the warm air above it in Summer and below it in Winter.  Otherwise trying to heat the air in Winter will result in a nice warm ceiling and cold people!

Trying to solve it with AirCon alone is not on unless you have a free electricity supply... speaking of which, why not put solar panels on the roof?  Removes (some of) the heating of the roof in Summer, and provides electricity to help power the AirCon - Win/Win!  :-)

Oh, and that roller-shutter is likely to be drafty in Winter, even when it's closed, so building something inside (an enclosed loading bay or something) to keep that cold air from the body of the bulding would be a Good Thing.

Cheers,


Howard Winter
St.Albans, England

2012\02\01@090221 by Howard Winter

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picon face
Joe,

Oh, and 1 Btu/hr is about 0.29W  :-)

Cheers,

Howard Winter
St.Albans, England

2012\02\01@185016 by IVP

face picon face
> Joe,
>
> I'm assuming you're talking about the building at the corner of Charles
> St.
> and Akepiro St. on the West side of the latter?  It seems to have 4 long,
> narrow rooflights, but it doesn't look like 1,000m^2, but looks could be
> deceptive

Hey Howard, long time no read

I tend to agree. I was told 1000 but on closer inspection of that photo it
seems more like 500. You'll notice that it's surrounded by concrete and
tarmac, for better or worse

> Well Job 1 is to get that roof insulated!  Solar energy can contribute up
> to 1kW per square metre on a good day, but even allowing for the angle,
> reflection and other losses you may find that tin roof is being hit with
> up
> to half a megawatt.  It makes no sense to let that heat in and then pay
> good money to get it out again

My offer so far has been to make at least one of those rooflights openable,
which would solve the short-term problem of them baking in summer. Which
it is now and they are. She's put up some lightweight material to keep the sun
off the floor and that's helping. But of course when it rains heavily, oh the
noise !! Only some decent continuous insulation/padding is going to block
that. Plus Auckland gets very humid in the summer so even on cloudy days
it can be quite uncomfortably warm and muggy, like it is today. Ugh

> If he doesn't need 5m of height, a false ceiling will help too, as it will
> tend to keep the warm air above it in Summer and below it in Winter.
> Otherwise trying to heat the air in Winter will result in a nice warm
> ceiling
> and cold people!

The previous premises (348 New North Road, very close, NW) was on
the lower floor, partly built into the hill, false ceiling, room divider, very
stable temperature. Good set-up. And that really was more like 1000sqm.
The people on the second floor offered her landlord more for the lease and
he accepted, although annoyingly she finds they may not use it themselves
after all, and will probably sub-lease. She's realised that moving in to this
place was a mistake but took it to stay in the area. If you were wondering

> Trying to solve it with AirCon alone is not on unless you have a free
> electricity supply...

At one of her previous buildings someone had either run a wire through
the wall to next door's fuse box or it was an oversight when the building
was divided. I went in to remove some strip lighting and made sure the
fuses were pulled. But one particular light's cable was still live and cutting
it ruined my expensive new snips. Grrrr

> speaking of which, why not put solar panels on the roof?  Removes
> (some of) the heating of the roof in Summer, and provides electricity to
> help power the AirCon - Win/Win!  :-)

Good idea but she'd probably baulk at the expense

> Oh, and that roller-shutter is likely to be drafty in Winter, even when
> it's closed, so building something inside (an enclosed loading bay or
> something) to keep that cold air from the body of the bulding would
> be a Good Thing

I think I need to have a chat with her. Mittens and bikinis ?

Thanks

Joe

2012\02\01@234731 by YES NOPE9

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One of the best way to deal with heating and AC cost is to limit heating and AC to areas that individuals inhabit.  See if you can limit the amount of cubic space that must be conditioned.  Thin walls or blankets or foam sheets can limit conditioned areas.  In my buildings and houses.... I condition only the areas that I live or work in.  The rest of the space I let vary widely temperature-wise.

99guspuppe

2012\02\02@015306 by IVP

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> I condition only the areas that I live or work in

I'm not an expert, but at a guess, and this is just a guess, that's
possibly the inspiration behind clothing ;-

2012\02\02@110827 by YES NOPE9

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Good point
My sports car has a modification ..... a flexible hose that leads from heater/AC outlet and goes under my jacket or shirt.
I drive with the top down and pump heat or cool next to my body
99guspuppet

> On Feb 1, 2012, at 11:52 PM, IVP wrote:
>
>> I condition only the areas that I live or work in
>
> I'm not an expert, but at a guess, and this is just a guess, that's
> possibly the inspiration behind clothing ;-)

2012\02\03@073704 by Howard Winter

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Joe,  (whatever happened to Jinx? :-)

On Thu, 02 Feb 2012 12:48:44 +1300, IVP wrote:

> Hey Howard, long time no read

Yes, I gave up trying to keep up with PIClist some time ago - I'm now about 25,000 messages behind (in OT, PIC, EE) so I just occasionally look at the current topics to see if there's anything interesting.

{Quote hidden}

Yes, letting the hot air out is useful, but only if the incoming "cold" air is tolerable!

I really think she needs to consider insulation and lowering the ceiling as top priorities.

>...
> The previous premises (348 New North Road, very close, NW) was on
> the lower floor, partly built into the hill, false ceiling, room divider,
> very
> stable temperature. Good set-up. And that really was more like 1000sqm.
> The people on the second floor offered her landlord more for the lease and
> he accepted, although annoyingly she finds they may not use it themselves
> after all, and will probably sub-lease.

That's pretty crap.  Doesn't the landlord object?  Surely if there was more money available to rent it out, he would like to have it!  (and I'll stop calling you Shirley :-)

>...
> At one of her previous buildings someone had either run a wire through
> the wall to next door's fuse box or it was an oversight when the building
> was divided. I went in to remove some strip lighting and made sure the
> fuses were pulled. But one particular light's cable was still live and
> cutting
> it ruined my expensive new snips. Grrrr

I suppose you didn't try it with a test-stick first, but then I wouldn't have either, when the "whole building" has the power off...  Maybe next time turn them all on first, to make sure they go off!

> > speaking of which, why not put solar panels on the roof? ...

> Good idea but she'd probably baulk at the expense

I understand - I'd love to have them but with zero money (gizzajob, someone!) it's never got within reach.  There was a *really* good deal here where any power you generated from Solar Panels was paid-for at 43p/kWh, which is about three times what you have to pay to buy it from the grid, but someone noticed how good a deal it was and they've just more-than-halved it.  Bummer!  Previously it would have paid for the panels in about 10 years, now they may never pay for themselves as they wear out after about 25.

> > Oh, and that roller-shutter is likely to be drafty in Winter, even when
> > it's closed, so building something inside (an enclosed loading bay or
> > something) to keep that cold air from the body of the bulding would
> > be a Good Thing
>
> I think I need to have a chat with her. Mittens and bikinis ?

Works for me - make sure you post photos!  :-)

Incidentally, I use an 8,000 Btu/hr, say 2400W, aircon unit in my living-room, which is about 20m^3, and with an outside air-temp of about +28C it holds its own keeping the room at +20C, but above that it starts to lose ground (just as a comparison with the project in question).  Luckily days above +25C here can usually be counted on one hand.

(Basking in the noon-day Sun at a balmy -1C.  May get snow tonight... )

Cheers,

Howard Winter
St.Albans, England

2012\02\04@040538 by IVP

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> Joe,  (whatever happened to Jinx? :-)

Ooooh, touchy subject

During tournament preparation, we were trying to implement
Stovold's 1953 Variations as a way to get out of Nip. Jinx
had some rather deep, a little too deep if you ask me, questions
about Warburton's Modification -

"NB - it is important to distinguish between the Diagonal and
the Oblique. Although they may appear to be interchangeable, as
indeed they usually are, they serve very different purposes when
Hewlett's Proscription is in force, or when the game is played
under Floodlights.

The Ob-lique, being the natural opposite of the Lique, is therefore
not related to the Monagonal line in the same way that the Diagonal
is, especially in the purlieu of, say, Kensington Olympia or Uxbridge.
Players trapped in Diagony, however, may well find themselves in
need of a Lique"

In the end I said, look, you can Nip for a Lique but only if it's a
Non-elliptical Trajectory. He hit the roof. Quite an achievement
I thought, better than I've managed when in Monagony. Then just
stormed off, on an illegal Tangent if you please, muttering something
about "Allbright always got away with it" and "I should get that
umbrella out of King's Cross Lost Property and shove .....". But
he was gone

Last I heard he was living with an imaginary family up the road. I
later found the Lique behind the couch. One of several, I suspect.
So, probably best all round

> I just occasionally look at the current topics to see if there's anything
> interesting

Gosh, I'm interesting

> My offer so far has been to make at least one of those rooflights
> openable,
>
> Yes, letting the hot air out is useful, but only if the incoming "cold"
> air is tolerable!

Which would be a problem in the summer, hot tarmac and all

> I really think she needs to consider insulation and lowering the
> ceiling as top priorities

After talking with her I get the impression she won't be re-newing
the lease, so will be there maybe only acouple of years. And she's
learned a valuable lesson. Or two. She's grateful for the insights
into AC as well

>> after all, and will probably sub-lease.
>
> That's pretty crap.  Doesn't the landlord object?  Surely if there
> was more money available to rent it out, he would like to have it!

He got his whack so is either happy or has to lump it. I met him
a couple of times. Can't say I warmed to him

> (and I'll stop calling you Shirley :-)

Roger

> it ruined my expensive new snips. Grrrr
>
> I suppose you didn't try it with a test-stick first, but then I wouldn't
> have either, when the "whole building" has the power off...  Maybe
> next time turn them all on first, to make sure they go off!

What's that they say about hindsight ? 20-20 ? !!

>> I think I need to have a chat with her. Mittens and bikinis ?
>
> Works for me - make sure you post photos!  :-)

Okey-doke. That would be to pervertnotgettingany@.....

Seeing the UK news lately I'm guessing mittens are the minimum
for you lot. Boy that's cold over there this year

> Incidentally, I use an 8,000 Btu/hr, say 2400W, aircon unit in my
> living-room, which is about 20m^3, and with an outside air-temp
> of about +28C it holds its own keeping the room at +20C, but
> above that it starts to lose ground (just as a comparison with the
> project in question)

Thanks, that's some good indicating. The two in the shop I tried to
get a look at must be fairly big then, because that enclosure is a
measured 30m x 30m x 3m, or 2700m^3. But is your living room
really that small - 5m x 4m x 1m ? Lot of Japanese furniture ?

> Luckily days above +25C here can usually be
> counted on one hand

Unless you didn't wear your mittens, in which case two hands and a foot

> (Basking in the noon-day Sun at a balmy -1C.  May get snow tonight)

You know you'd only be wasting time tomorrow discussing "Thought
we'd get snow last night" if you didn't

> (gizzajob, someone!)

http://abcnews.go.com/blogs/headlines/2012/02/man-steals-glacier-for-designer-ice-cubes/

I hear they're running out of coal in Newcastle. Off you go

2012\02\09@092154 by Howard Winter

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picon face
Joe,

On Sat, 04 Feb 2012 22:05:33 +1300, IVP wrote:

> > Joe,  (whatever happened to Jinx? :-)
>
> Ooooh, touchy subject

Sorry!

>...
> Last I heard he was living with an imaginary family up the road. I
> later found the Lique behind the couch. One of several, I suspect.
> So, probably best all round

Ah, Mornington Crescent - haven't had a good game of that for a number of years.  Or, indeed, a bad game...

> > I just occasionally look at the current topics to see if there's anything
> > interesting
>
> Gosh, I'm interesting

Yes.  Or trying to air-condition an aircraft hanger with a couple of icecubes and a pocket fan, is...

>...
> Seeing the UK news lately I'm guessing mittens are the minimum
> for you lot. Boy that's cold over there this year

Yes, it has been a bit brisk.  6" of snow on Saturday evening did for the half-marathon the next morning, where I was supposed to be helping with communications.  Luckily we got the stand-down in time not to have to get up early!  That's a point, is there an NZ-equivalent of RAYNET (UK) and ARES (USA)?  That's Radio Amateurs (Hams) who volunteer to provide comms in emergencies, and do so at community events like charity walks, runs, cycle and horse rides, etc?

>...
(2400W, 20m^2)

> Thanks, that's some good indicating. The two in the shop I tried to
> get a look at must be fairly big then, because that enclosure is a
> measured 30m x 30m x 3m, or 2700m^3. But is your living room
> really that small - 5m x 4m x 1m ? Lot of Japanese furniture ?

:-)  (measures) It's 2.5m high, 3.7m long, 3.1m wide, less a chimney-breast of .38 x 1.25, so I make that about 27.5m^2, so I was un-exaggerating a bit...

It's a small 3-bedroom semi- built in 1937, just before the war, and it still has cracks in the ceilings from when the Luftwaffe tried to bomb the Handley Page aircraft factory, about a mile away.  So in the way of houses built then, the rooms are pretty small, and it has 9" solid brick walls, so pretty naff when it comes to options for insulation.  So I'm wearing an Arran sweater, and tapping my feet to fend off frostbite.

>...
> > (gizzajob, someone!)
>
> http://abcnews.go.com/blogs/headlines/2012/02/man-steals-glacier-for-designer-ice-cubes/

Blimey, some people will nick anything!  Couldn't he have made his own by putting bubbles into ordinary icecubes?  They'd never know, I'm sure.  I wonder if the evidence will still be there when it comes to court?  ("Police were unable to produce solid evidence of the theft..." :-)

> I hear they're running out of coal in Newcastle. Off you go
My sister lives near there, and they don't use coal fires these days, it's all gas.  Not so easy to take there and sell from the back of a lorry, unfortunately!

Cheers,

Howard Winter
St.Albans, England

2012\02\09@101124 by alan.b.pearce

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> Yes, it has been a bit brisk.  6" of snow on Saturday evening did for the half-
> marathon the next morning, where I was supposed to be helping with communications.
> Luckily we got the stand-down in time not to have to get up early!  That's a point,
> is there an NZ-equivalent of RAYNET (UK) and ARES (USA)?  That's Radio Amateurs
> (Hams) who volunteer to provide comms in emergencies, and do so at community events
> like charity walks, runs, cycle and horse rides, etc?

Yes, they do have a network that provides comms for events, a colleague, when I was there, helped with doing comms for car rallies, including the NZ Rally that is/was part of the WRC. They also have periodic civil defence exercises for earthquakes etc emergencies.

In Didcot all the snow (well all of an inch if we were lucky) has disappeared except where it has been shovelled into piles in the car park here at work, but the temperature has been that cold that there is no moisture in the air to frost overnight. One of my mates from near Reading in Berkshire reckons they had much more there.

There is supposed to be a dose of snow coming tonight, so we'll see how thick that gets.


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