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re: heres an idea for alternative air conditioning...
12 jun 2000
db tech wrote:
>db said..[with] a water cooled freon condensing unit, as opposed
>to water cooled air. i would think that twenty btu's per watt
>hour could be attained.
an article of faith?
>>the best i've heard of is lennox's 14 seer, ie 4.1 w/w.
>i assume that you are referring to an air cooled condensing unit here.
as i recall from about 3 years ago, this was a water source system.
>carrier claims to have a unit of 16 seer. keep in mind
>here that seer is not eer. (btu's per watt hr.)
thanks for pointing that out.
>seer (official definition)
>seasonal energy efficiency ratio. "a measure" of cooling
>efficiency for air conditioners.
sounds vague. is there an official seasonal test temperature profile?
>i have a 4 ton (48,000 btu/hr) heat pump that is rated at 12
>seer, but when i do the numbers on power used on a/c-btu's, i
>come up with 10 btu's per watt hour. (eer=10)
seems like there must be a more efficient scenario, to bring the
seasonal average up to 12. open the windows on a cool night? :-)
>i believe that an "ideal" water cooled freon condensing unit/a/c
>could easily double this figure.
i believe that someday someone will manufacture an efficient solar
pool cover/heater, but i haven't seen any for sale yet...
>>compare this to a 1/25 hp grundfos pump pushing 5 gpm of 55 f
>>water through 4 magicaire 800 btu/h-f coils in the airpath of a
>>100 w 25k cfm ceiling fan--about (80f-55f)3200btu/h-f = 80k btu/h
>>or 23.4 kw of coolth... 38 times more efficient than freon,
>>even without condensation.
grainger's 56" 265 rpm 25.5k cfm ceiling fan is actually rated
at 110 w. would it use 14 watts at 133 rpm? :-) maybe we should
run a few thousand feet of toby's cheap 5/8" black agricultural
hose around the ceilings in gutters.
>...but also consider the fact that a freon a/c unit can maintain
>a much lower humidity, which means that you can run a higher
>temperature for the same comfort.
can you compare apples to apples?
i think you wrote the first sentence below, and i wrote the second.
>if the exit air temperature is above the dew-point, then there
>is no dehumidifying. there's no dehumidification if the coil is
>warmer than the dew point of the air near the coil.
>>the exit air might be a lot warmer. ???????
and you added the ??????? when i said the air near the coil may be
cooler than the exit air, so maybe it isn't accurate to say "if
the exit air temperature is above the dew-point, then there is
no dehumidifying."
(newsgroupies typically quote others using a > at the start of the
line, and follow their comments on the next line with no >. more >s
build up as dialogs progress.)
>>i didn't mention slow-moving air.
>you did say a slow turning fan, which implied slow moving air.
i was thinking that large low rpm fans use less power. pe norman
saunders says the efficiency of a fan is about the same as the
blade diameter in inches, and halving the cfm reduces the power
by a factor of 8, no?
>>my $35 used 1984 dodge omni auto radiator with its attached 12
>>v fan keeps my house about 80 f on a 100 f day with
>>condensation, using about 2 gpm of 55 f well water.
>must be a very small "tight" house with super insulation.
nope. an old farmhouse with r10 foam insulation outside the stone walls.
>a radiator would not be very efficient in this application for
>removing humidity. (not of counter flow design)
got any numbers?
>i have question/doubt about the relative humidity % of the 80 f
>outlet air?
dunno... 80 f was the house air temp. the outlet air may have
been close to 100% at 55 f...the outlet air temp was about 70 f.
>if i was going to build a direct water heat exchanger a/c
>system, i would like to derive my source of water from a large
>deep lake that would have near bottom water temperatures at or
>below 40 f all year round. there are many lakes like this. i
>would insulate the water source pipe. i would, design/build or
>purchase a large efficient counter flow heat exchanger that
>would go into my heating plenum/main duct. (3000 sq. ft. house)
chacun a son usine a gaz.
nick
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