Re: New Efficient AC

From: The Ghost In The Machine (ewill_at_sirius.athghost7038suus.net)
Date: 03/26/05 

Date: Sat, 26 Mar 2005 19:00:09 GMT

In sci.physics, Greg Neill
<gneillREM@OVE.THIS.netcom.ca>
 wrote
on Sat, 26 Mar 2005 08:23:24 -0500
<fmd1e.38136$nK.1716804@news20.bellglobal.com>:
> "erich" <shengar@aol-dot-com.no-spam.invalid> wrote in message news:424548b8$1_1@127.0.0.1...
>> Dear Folks:
>>
>> This is the biggest break through in AC I've seen. My only question is
>> if there is a maintainence issue with the build up of deposits of any
>> sorts in the channels due to poor water quality.
>>
>> http://www.coolerado.com/NewsAndNotable/DelphiIdalexCoolerado.htm
>> Posted at: http://www.groupsrv.com
>>
>
> "The Coolerado Cooler uses a thermodynamic cycle called the Maisotsenko
> Cycle. The Maisotsenko Cycle is a thermodynamic cycle that capitalizes
> on a natural, clean, energy or psychrometric energy found in our
> atmosphere."
>
> Riiiiight. Load of crap.
>

The question is: does it work? Testimonials notwithstanding, I for
one would propose an experiment, in three of six identically
configured rooms along a row (the other two are there to thermally
isolate the rooms from another side of the building):

[1] A Coolerado cooler.
[2] A standard A/C unit of the adiabatic/isothermal
    compression/expansion cycle.
[3] A "swamp cooler", which is basically a unit that allows dry
    outside air to flow through a wet mesh; the air cools
    and humidifies. Such units are fairly common in desert locales.
    And yes, they're subject to deposits, unless one uses distilled
    water.
[4] A control room, in the sense of being an experimental control,
    that is (although a monitoring room might be placed somewhere
    else in the building); this room would contain no cooling
    apparatus under test.

Rooms would also have fans and such to get them to the same
temperature prior to the actual test; there might also
be pipework in the walls which would not be part of the
experiment proper, but would simply be used to cool or heat
the rooms prior to the test. There would also be a number
of thermometers and hygrometers scattered around each room,
taking measurements during the test. Power meters would
also be installed, and their measurements taken after and
possibly during the test.

No doubt this sort of stuff is routinely done during testing of new
air conditioning units anyway.

The description given by the Weblink above suggests that the Coolerado
is nothing more than a garden-variety swamp cooler. An excerpt:

        The HMX is the key component in the air conditioner
        that uses water as the medium for cooling. In
        addition, the air conditioner does not use a
        compressor or chemical refrigerants, and the only
        electricity required is for a fan to move air.
        The HMX works by saturating a working air stream
        with water that incrementally pulls heat away
        from both the product and working air streams
        through unique flow path geometries. The result
        is unprecedented economical and energy efficient
        cooling.

A more sophisticated explanation, however, suggests that there's
more to it than that:

http://www.idalex.com/technology/

I think there's something there, though I for one would hope that
the above explanations avoid terms such as "psychrometic energy".
The Idalex link also makes no mention at all of whether the
air ("product") flowing through its system condenses at all,
interfering with the ability to cool. And yes, it turns out they
do, unfortunately, use the term "psychrometic energy".
The term is not in dictionary.reference com, though the
term 'psychrometer' is -- it's simply a doodad one occasionally
sees whirled through the air (or perhaps air blown across it,
if it's a stationary unit) with two thermometers in it, one
dry, one wet.

There *is* energy associated with evaporation, but it's an
unfortunate usage -- and I still say it won't work in Boston
(90F, 95%-100% humidity) though it might work in Arizona
or Palm Springs. It is also far from clear how well this
device will work with a water feed at the same temperature
as the outside air feed.

One might get better results from a garden-variety mister in
front of the store -- a device, BTW, that is also in common
usage in desert climates.

http://www.idalex.com/applications/MCTC.htm

is a bit odd, in that it uses two coolers -- one to cool the
incoming compressor air (logical enough, since compressors
tend to heat air), and one to cool the compressed air again
before it goes into the turbine, by using the exhausted air
from the turbine. At least, I think that's what they're doing.

The real trick: take the condenser water and use it exclusively.
No fair cheating by borrowing water from the local water supply
(which turns out to be relatively cool) and turning it into
humid water vapor.

As a side issue, this also mentions "60%" as a heat efficiency.
If one assumes a 90 degree F hot outside air temperature, that
translates into 305 K. The theoretical Carnot efficiency of an
engine is

Eff = (t_Hot - t_Cold) / t_Hot

Plugging in:

.60 = (t_Hot - 305) / t_Hot
.60 * t_Hot = t_Hot - 305
0 = t_Hot * .40 - 305
305 = t_Hot * .40
305/.40 = t_Hot = 762.5K = 489C

which would be a very high-pressure boiler indeed.

Even at 0C it wouldn't make that much difference:

273/.40 = t_Hot = 682.5K = 409C

A Google on "high pressure boiler" coughed up, among other things,

http://www.mckenziecorp.com/hurstboiler.htm

which has some peculiar nomenclature -- HP is used frequently,
for example; I'm assuming that means horsepower, which
converts to watts. Makes sense, actually. There's also
the nomenclature '300# steam'. I'm assuming '#' is a
pressure measurement (psi?) but it's not entirely clear.
300 psi = 2.07 megaPascal. Since scuba tanks go up to 3300
PSI or 22.7 megaPascal (albeit at far lower temperatures)
this seems a bit on the low side.

http://www.scuba.com/shop/product.asp_category_131

However, the page refers to other pages, which are
mildly interesting from an industrial standpoint -- there
are also devices to degass the incoming water, for example
(an issue I for one would not have considered, but
presumably dissolved oxygen might do nasty things to high
temperature steam systems).

The critical point for water is 373.946 C or 647.1 K,
and at that temperature the vapor pressure is 22 megaPascal
or 3,190 pounds per square inch. It's not clear to me
what happens at temperatures and pressures above this point,
though the page suggests that there is no phase transition
as such; above that pressure/temperature one gets only
water vapor.

2.07 megaPascal cooresponds to a boiler temperature somewhere
above 200C.

http://www.iapws.org/faq1/boil.htm

It is possible the document is referring to 60% of the
theoretical Carnot efficiency, as opposed to 60%
total fuel energy extraction efficiency.

In conclusion: I don't see it being better than conventional
technologies at this time, without more analysis. 

-- 
#191, ewill3@earthlink.net
It's still legal to go .sigless.

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