Aquaponics Digest - Sat 11/13/99
Message 1: OK, Then moving on...
from Bill
Message 2: Re: heating revisted
from "Barry Thomas"
Message 3: Re: heating revisted
from MUDDTOO
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| Message 1 |
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Subject: OK, Then moving on...
From: Bill
Date: 12 Nov 99 23:24:53 PST
>I've just discovered (thanks to Gordon's mail problems) =
that our welcome message has gone missing - lost in cyber-never-never-lan=
d.
Thx! Wondered about that. But it's agood buncha folks here!
Still, one of the BEST (long or not) intro's I've seen.
>best heat storage media that doesn require a team of
tech's and a national evacuation plan - plain water?
> sensible heat, must consider the cost benfit ratio.
And plain water can have a dual use. =
>I believe that the most effective heat storage medium is
the one that is commonly used, water. It is cheap, safe,
and thermally efficient. =
Now that that's settled,
(altho energy cell folks may email me... :>)
To keep your tanks, which are ___ gal, in a ___ or greenhouse
environment, which is insulated with ___, what wattages are
generally found to be required (or gas?) and what duty
cycle or electricity cost is generally incurred?
How warm is the ambient situation... for the plants...
>Have you thought of getting a few of the water spaniels
and just letting them chase birds to their hearts content?
This is good! A pair would make it a game for each other!
The 'gun' woyuld be for weekends, to let the people and dogs
"off the work-week leash," and keep the required irregularity.
>Could you not replace the acetylene tank, regulator etc
with a small electrolysis unit? Just feed the gases straight
into the gun. Eco friendly - only output is water and bang.
I like how you think... tho' acetylene does give a nice =
black smoke ring, as I recall, a visual stimulus, with the noise.
But I have interest in the anode/cathode materials
required for this... Copper corrodes, even if AC used.
And I want DC, to separate the gasses. I've used carbon rod.
Electrolysis tends to be inefficient, and oxygen generators
use a catalyst, but I've been unable to discover what.
I am waiting for approval to join tilapia and fish lists,
and figure they are used to low DO in an 80 degree environment,
but wonder if anyone has done a cold water tank, their
choice of aquatica (OK term?) and wonder if anyone has
oxygenated via electrolysis. (I know about the Hindenberg.)
I know I have a million questions, and some =
(now that I have the Intro) are borderline off topic,
thanks for your forebearance and kindness, as well as
interest and detailed research!!!! You know who you are!
Thx all, Bill OOWON@Netscape.net SF Bay Area
P.S. Trying to help two kids doing a high school =
hydroponics project find a small pump. 25-60 gph.
New Mexico. Gave standard advice where to look, ask.
If you have one, CHEAP... :>)
____________________________________________________________________
Get your own FREE, personal Netscape WebMail account today at http://webm=
ail.netscape.com.
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| Message 2 |
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Subject: Re: heating revisted
From: "Barry Thomas"
Date: Sat, 13 Nov 1999 19:40:39 -0000
> >came across a table of materials which listed brine (25%
> >wt. - didn't say what kind) as having a specific heat
> >capacity of 3.4.
> May I suggest that you check your source again. A
> probable explanation to the statement that the specific
> heat Cp of brine being 3.4 is the units for Cp. One of
> the conversions for specific heat is
>
> 1 Btu/lb deg F = 4.187 Kj/Kg deg K
Ron, you are of course 100% right. A whole load of other stuff I was was
looking at then was given in relative values. This particular table
though was indeed giving absolute values in kJ/kg K - a fairly vital
point which I somehow managed to miss. Apologies to all.
So, water it is then.
Can't help thinking about adding some kind of antifreeze to the heat
sink though, mainly to allow it to operate at lower average temp,
reducing gradient across insulation (this is for the system using heat
pumps). But I suppose that anything you add to the water is going to
reduce the capacity of the sink, most likely cancelling the gain? Oh
well... Water seems pretty good on its own - anything else would just
have been a nice bonus.
Thanks,
Barry
barrythmas@crosswinds.net
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| Message 3 |
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Subject: Re: heating revisted
From: MUDDTOO
Date: Sun, 14 Nov 1999 00:49:34 EST
In a message dated 11/13/99 11:42:30 AM Pacific Standard Time,
barrythomas@crosswinds.net writes:
>
> Can't help thinking about adding some kind of antifreeze to the heat
> sink though, mainly to allow it to operate at lower average temp,
> reducing gradient across insulation (this is for the system using heat
> pumps). But I suppose that anything you add to the water is going to
> reduce the capacity of the sink, most likely cancelling the gain? Oh
> well... Water seems pretty good on its own - anything else would just
> have been a nice bonus.
>
Hello Barry,
The real trick is capturing and keeping the solar radiation when it's needed
and getting rid of it when you don't. In Florida this solar radiation is
equal to about 900 btu/sq ft in the winter and about 2500 btu/sq ft in
summer. That's instantaneous radiation, not a daily total. No wonder the
greenhouse gets Soooo hot in the summer! 55 gallon barrels painted flat
black work well as heat collectors and are a cheap and effective way to
stabilize indoor temperatures during winter months. There are other
inexpensive methods to use to reduce inside temperatures during the summer
months also.
Just a thought - couldn't the heat storage water in winter also be the same
water used to grow the fish? I think so.
Joel
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