re: evaporative cooler question
25 jan 2005
abby normal wrote:
>> the floors are automatically dampened beneath around 3 am.
>so there is no vapour barrier beneath the slab?
no. plastic film on the ground, under stone, under concrete.
>you are wetting the soil.
>or the watering system is between the slab and the insulation?
over the film and under the stone. or maybe just a soaker hose on top.
>it is a suspended slab now.
>> >wetting a floor slab, can probably give an average dry bulb temp
>> >that falls in the comfort range, but the process to get there will
>> >take occupants through discomfort of overly high humidity or dry bulb
>> >temperature to get there.
>> nope... 75.5 f with w = 0.012 is comfortable, and that's the min slab
> >temp. house air can be warmer.
>you are assuming that you will get the conditions.
>the slab then adds humidity without sensible heat removal?
evaporation cools the slab enough to keep the house 80 f all day.
>evaporation heat will come from the slab.
evaporation is exothermic? :-)
>then your ceiling fans blow hot air down to the slab to cool off?
ceiling fans as needed to keep the house air 80 f.
>model how it happens...
i've done so. where is your numerical model?
>...don't assume setting the a dehumidistat to turn on an exhaust fan
>is going to do this.
what's wrong with that? what do you mean by "this"?
>indoor conditons will be well out of the comfort zone as you travel
>from point a to point b.
why would you say that? where are points a and b in this case?
>my parents in canada have an old house. no vapour barrier under the
>slab, so moisture comes in. happens in winter as well. also the baement
>walls lose heat as well. basement will be cool in canada or pa as they
>are in contact with cool wet soil. what's the point out in the desert?
more efficient house cooling using a slab on-grade in the desert.
let's try logic again. would you agree that:
1. 80 f with w = 0.012 is comfortable.
2. at 80 f and 100% rh, pw = 1.033 "hg.
3. at wc = 0.012, pa = 0.566 "hg.
4. p = 0.1a(pw-pa) lb/h will evaporate from an a ft^2 wet surface.
5. evaporating p lb/h of water indoors makes about 1000p btu/h of cooling.
6. removing it takes c cfm of exhaust air, where p = 60c0.075(wc-wa)=0.0367c.
7. cooling the house and c cfm from ta (f) to 80 f makes 1000p=(ta-80)(98+c).
8. we can store 34k btu of coolth in a 10k btu/f slab with a 3.4 f temp swing.
do you disagree with any of these statements? which ones?
what's the conclusion?
(1) every idea of mine, that cannot be expressed as a syllogism,
is really ridiculous.
(2) none of my ideas about bath-buns are worth writing down.
(3) no idea of mine, that fails to come true, can be expressed as a
(4) i never have any really ridiculous idea, that i do not at once
refer to my solicitor.
(5) my dreams are all about bath-buns.
(6) i never refer any idea of mine to my solicitor,
unless it is worth writing down.
using these letters: a is able to be expressed as a syllogism
r is really ridiculous
b is about bath-buns
c comes true
s is referred to solicitor
d is a dream
w is worth writing down,
1. ~a-->r (~ means "not") from _the complete works of lewis carroll_,
2. b-->~w random house/modern library, page 1256.
since d and c are the only unpaired terms above, the conclusion involves them.
starting with d in equation 5,
"all my dreams come true" :-)