Efficient use of Air conditioner

[Harry Conover]

Sure, it's possible but rather pointless.

Harry C.

[jmfbahciv]

Like you did not do?

Sigh! I'm out of Kleenix; you'll have to get your own and apply it to your nose.

/BAH

Subtract a hundred and four for e-mail.

[Stormin Mormon]

If I trim excess text on the complaint email, it wouldn't make the point. How about review several of my other posts? Maybe you can spot what my real posting pattern is? or are you too busy looking for reasons to complain?

NOTE: Please do not quote or atribute people who are busy being complaining jerks. (Guess I didn't do that either?)

[HeatMan]

Ever heard of a remote condenser??

[Wayne]

[e-mail] wrote in news:4104e01f$0$5640$ [e-mail]:

Pay no attention to the man behind the curtain. :-)

[jmfbahciv]

Or the screen. At least he knew he was a fraud.

/BAH

Subtract a hundred and four for e-mail.

[CBHVAC]

Gee...and all these resturants must be obsolete..:)

[HeatMan]

Hey, if the Bride would let me, I'd have a remote condenser for my HH 'fridge. Of course, it would be a commercial 'fridge too....

[Stormin Mormon]

We agree. Pointless.

[TURTLE]

This is Turtle.

Stormy , Refrigerators are not designed to run in outdoor / Ambiant temperatures because it tells you to turn the refrigerator off or not run the refrigerator in temperatures above 95ºF . If you set it up like this you would have to turn your refrigerator off when it gets hot outdoors. I like to keep my refrigerator running all the time and not just when it is cool outdoors.

TURTLE

[~^Johnny^~]

Revco rocks! :-)

Whatever happened to them?

-- -john wide-open at throttle dot info

~~~~~~~~ "Stealing our copyright provisions in the dead of night when no-one is looking is piracy. It's not piracy when kids swap music over the Internet using Napster..." - Courtney Love ~~~~~~~~

[~^Johnny^~]

BINGO!

Maybe I should have just left it at that...

BUT!

Air over condenser -- Intake: from living space Exhaust: to outdoors

why not?

It's a few hundred watts of unwanted summer heat!

-- -john wide-open at throttle dot info

~~~~~~~~ "The first step in intelligent tinkering is to save all the parts." - Aldo Leopold ~~~~~~~~

[~^Johnny^~]

I am not going to touch that one with a ten foot (three meter) pole!

;->

-- -john wide-open at throttle dot info

~~~~~~~~ "Stealing our copyright provisions in the dead of night when no-one is looking is piracy. It's not piracy when kids swap music over the Internet using Napster..." - Courtney Love ~~~~~~~~

[~^Johnny^~]

100% correct. Gotta block them rays, or forget it!

-- -john wide-open at throttle dot info

~~~~~~~~ Marriage is the chief cause of divorce. -Groucho Marx ~~~~~~~~

[~^Johnny^~]

I live in a 600 sq ft cottage. I also live in a mild climate, but I run a lot of electronic stuff. Add 80000 BTU/hr for that.

Bottom line, my calculations for cooling come out to 22,000 BTU/hr.

Take off my 8,000, and you still need 14,000. That's for a 600 sq ft cottage in Northern California, on the coast (literally). Ten miles from the beach!

5000 BTU/hr?

I love geek chicks (I am married to one), but, respectfully: NO WAY!

Sorry, bah.

-- -john wide-open at throttle dot info

~~~~~~~~ Maybe I should ask Radio Shack. They claim they've got answers; but frankly, if Radio Shack were our provider, we'd _really_ be in trouble now, wouldn't we? ~~~~~~~~

[~^Johnny^~]

should read:

Add 8000 BTU/hr for that.

sorry 'bout that

-- -john wide-open at throttle dot info

~~~~~~~~ I don't know of anybody that has a perfect life - Marie Osmond ~~~~~~~~

[The Ghost In The Machine]

In sci.physics, ~^Johnny^~

wrote on Sat, 31 Jul 2004 20:40:07 -0700 :

Hmph. Metrically challenged. :-P

But lessee.

600 ft^2 = 55.75 m^2

Assuming your ceilings average 2.5m (my ceilings are 94" = 2.39m, but there are issues such as entryways and high ceilings), one gets a total volume of 139.38 m^3.

A computer runs typically 300W, maybe 400W nowadays. (I'm not entirely certain if the rating on the power supply is the consumption from the wallsocket or the production at the motherboard/device level.) 400W translates to 1.44 megaJoules/hr.

5000 BTU = 5.27529726 megaJoules, according to Google. 5000 BTU/hr = 1465 W.

An interesting computation is to take a single 100W light bulb and place it in a room which is sealed (in the thermal sense). Assuming your dimensions above, a pressure of 101350 Pascal, a standard air composition of 29 grams/mole, a room temperature of 20 C = 293 K, and 1 degree C per kg-cal (which probably isn't quite right, as this is for liquid water, not air) or 4180 J per kg-K, and doing a bit of other hand-waving approximation (heated air expands, for example), one gets

n = PV/(RT) = 101350 * 139.38 / (8.314472 * 293) = 5798.58 moles or 168.2 kg.

and then one gets

702.9 kiloJoules per degree C temperature rise.

100 W = 360 kiloJoules per hour.

Not exactly the World's Best Heater, is it? :-) It would take almost 2 hours to increase the temperature in the domicile by

1 degree Celsius with that light bulb. Therefore, there's a bit of slop available here.

Even with a good 1800 W heater it would take almost

7 minutes to raise the temperature of your air 1 degree C.

I'd be more worried about the insolation -- which is

1,350 W/m^2. Since we've established you have 55.75 m^2 of roof area, and can compute that you have, according to my figures, at least approximately four 25 m * 2.5 m = 62.5 m^2 walls, or 250 m^2 of walls, of which half might be illuminated at any one time (there are a *lot* of issues here, though, as the tilted sun will be looking at something generally hexagonal, and you're probably not living in a big box anyway, but a bunch of smaller ones, with corridors :-); however, the sunlight also reflects off the ground onto your housewalls ), yielding at the very most an additional heat load of 244 kW, and probably less than that, depending on what color your exterior walls and roof are. That'll heat up the air in a hurry: 35 seconds per degree C temperature rise.

It gets weirder if one factors in the heat retentitivity of the walls as well. Air isn't the only thing that heats up. Also, the heat leaks through the walls (either direction), which is one reason people like high R-factor insulation in colder climes (and should in warmer climes, too).

So as the air in the home heats up, the heat will leak out, too (it's not nearly as sealed as a hypothetical thermodynamic system!) back to the ambient -- although admittedly the ambient air is also heating up because of good old Sol.

I'd need more data -- average temperature swings in your area and all that -- before I can make a more detailed computation, assuming I'm even close to right here; I'd have to look at the thermal characteristics of nitrogen, for instance, to make a more accurate determination of how fast the air will heat up.

gives me no less than five constants for N2 gas, in rather inconvenient but workable units (1 mole N2 = 28 grams; however, our atmosphere consists of very roughly a mixture of 4 parts nitrogen, 1 part oxygen, and a smidge of argon, which is why I used 29 grams/mole earlier).

And of course there's probably a good HVAC estimator somewhere on the Web anyway. :-) An interesting side issue: there is an old unit of "1 ton" of air conditioning. Apparently the basis was the cooling capability of 1 ton of ice, but the standard conversion is now about 1 ton = 12,000 BTU/hr, although I'm not entirely sure.

[.sigsnip]

[~^Johnny^~]

Very good.

Condensate is often slung into the condenser airstream, usually by friction drag. It mostly evaporates before ever reaching the condenser coil, thereby avoiding additional corrosion of the equipment.

-- -john wide-open at throttle dot info

~~~~~~~~ "Stealing our copyright provisions in the dead of night when no-one is looking is piracy. It's not piracy when kids swap music over the Internet using Napster..." - Courtney Love ~~~~~~~~

[Stormin Mormon]

Well, an 80,000 BTU air conditioner that only draws about 7 amps of 115 VAC and weighs about 60 pounds..... I'd like one, too! We can sell them on Ebay!

[udarrell]

It appears an extra zero may have been added.