Aquaponics Digest - Fri 09/10/99
Message 1: Re: Evaporative cooling
from Dan Settles
Message 2: Re: pH Problems
from Joy Pye-MacSwain
Message 3: suscribe
from Bertmcl
Message 4: Re: Evaporative cooling
from "Barry Thomas"
Message 5: Re: Evaporative cooling
from
Message 6: RCPT: Re: Evaporative cooling
from
Message 7:
from
Message 8: RCPT:
from
Message 9: Re: RCPT:
from S & S Aqua Farm
Message 10: Re: RCPT:
from
Message 11: RCPT: Re: RCPT:
from
Message 12:
from
Message 13: RCPT:
from
Message 14: Re: RCPT:
from S & S Aqua Farm
Message 15:
from
Message 16: Re: Evaporative cooling
from Ronald Polka
Message 17: RCPT:
from
Message 18: Re: Re: Evaporative cooling
from "Barry Thomas"
Message 19: Re: pH Problems
from "William Brown"
Message 20: Re: Re: Evaporative cooling
from
Message 21: Re: Re: Re: Evaporative cooling
from "Frank Stancato"
Message 22: Fwd. New product requests
from S & S Aqua Farm
Message 23: Re: Evaporative cooling
from "Barry Thomas"
Message 24: Re: Evaporative cooling
from "Barry Thomas"
Message 25: Free Guide to Building a Cooler!!!!
from Mike Strates
Message 26: Re: Need off grid advice
from "grizzly"
Message 27: Re: Evaporative cooling
from "grizzly"
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| Message 1 |
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Subject: Re: Evaporative cooling
From: Dan Settles
Date: Fri, 10 Sep 1999 08:38:38 -0400
> Forgive what is probably a stupid question but as the main limiting factor
> in the effectiveness of evaporative coolers is the RH, why not use a
> dehumidifier or two? Especially in the more closed, possibly CO2 enriched
> GHs that Adriana and others were talking about recently.
If you add a dehumidifier it will increase the temperature more than the
few degrees you dropped it by using the evaporative cooler. The only way
to avoid this would be to remove the heat created by the dehumidifier
from the greenhouse. The unit would then basically be an air
conditioner. At that point you should just throw out the evaporative
cooler, turn on the air conditioner and watch the electric meter spin
rapidly.
Dan Settles
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| Message 2 |
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Subject: Re: pH Problems
From: Joy Pye-MacSwain
Date: Wed, 10 Sep 1980 10:18:48 -0300
Thanks Claude...... I just switched over to using potassium carbonate
yesterday....
I like the idea of killing two birds with one stone. Hummm... will check out
for root rot in the affected nodes, but I suspect that is not the whole problem
because one of the affected nodes only has three beds, half planted with
tomatoes
and otherwise is planted in lettuce. The tomato plants have only been in
that node
for half the time that they have been in the other two affected nodes. The
lettuce
was only added two weeks ago. I could possibly see root rot happening in the
older established nodes but not in this recently planted and only lightly
planted
node,
however at this point I am willing to look at any potential problem. Thanks for
your
thoughts.......
Joy
Claude Gelinas wrote:
> Potassium carbonate can be use as a substitute for your normal potassium
source
> and will increase pH.
>
> I'm not shure but pH drop can be caused by root mortality in hydroponic
system.
>
> Claude,
>
> --
>
> Claude Gélinas Agr., D.T.A.
> PHYTO Ressources
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| Message 4 |
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Subject: Re: Evaporative cooling
From: "Barry Thomas"
Date: Fri, 10 Sep 1999 14:52:39 +0100
Hi Dan,
> > Forgive what is probably a stupid question but as the main limiting
factor
> > in the effectiveness of evaporative coolers is the RH, why not use a
> > dehumidifier or two? Especially in the more closed, possibly CO2
enriched
> > GHs that Adriana and others were talking about recently.
>
>
> If you add a dehumidifier it will increase the temperature more than the
> few degrees you dropped it by using the evaporative cooler. The only way
> to avoid this would be to remove the heat created by the dehumidifier
> from the greenhouse. The unit would then basically be an air
> conditioner.
Didn't want to take up too much bandwith on the list but it seems I went too
far and didn't say enough here.
I meant that only the 'cold end' of your dehumidifier should go inside the
greenhouse with the warm bits outside. So the dehumidifier should help lower
internal temps directly as well as indirectly via evap cooling(?).
Or is this what you meant by an air conditioner? I live in the UK -
knowledge of these devices is rarely a top priority. :)
Also occurs to me that a reduced RH should increase transpiration. Might the
plants themselves not act as coolers? The energy to change the the state of
the water in the plants from liquid to gas must come from somewhere?
> At that point you should just throw out the evaporative
> cooler, turn on the air conditioner and watch the electric meter spin
> rapidly.
More rapidly than when powering large exhaust fans? Also, the large volumes
of air use by fans must make any other form of atmosphere control (CO2
enrichment, filtration etc) very difficult. Might the
performance/reliability enhancements potentially available from a more
closed GH not offset the extra costs?
I'm not, in this or other posts, trying to say 'do it this way' or 'this is
the way things are'. I assume these ideas have already been thought of and
discarded. Just trying to understand why. :)
Barry
barrythomas@btinternet.com
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| Message 5 |
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Subject: Re: Evaporative cooling
From:
Date: Fri, 10 Sep 1999 10:17:51 + 5 EST
Barry,
Just a thought.......
If your'e raising fish in your greenhouse (or even if you are not it might
work better for you). I am a
teacher in Upstate NY and we are trying to "kill two bidrds with one stone"
on the heating/cooling
end of things. If you are able to sink the "hot" end of the air conditioner
in a fish tank (large) you
would be able to heat your water for fish growth and still benefit from the
cooling in the house. This
may be difficult and may not be the recommended way, but it works for us.
Just have to lengthen
the lines on your AC unit.
Simply something we have tried with some success. I don't think we are
talking on the same scale,
however and would not recommend this until you speak with someone a bit more
qualified!
Mike
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| Message 7 |
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Subject:
From:
Date: Fri, 10 Sep 1999 10:24:22 + 5 EST
Hi All,
If ANYONE knows where I can get catfish (either shipped via air or by me
picking them up) in the
Northeast (upstate NY - near Syracuse) PLEASE PLEASE PLEASE let me know.
Our school year
has just begun and we are as yet unsuccessful in locating some for our
students to raise in
Aquaculture class. Looking for fingerlings for our system, but any source
would be appreciated!
Mike Comet
mcomet@south-lewis.moric.org
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| Message 9 |
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Subject: Re: RCPT:
From: S & S Aqua Farm
Date: Fri, 10 Sep 1999 09:47:36 -0500
At 10:48 AM 09/10/1999 EST, you wrote:
>Confirmation of reading: your message -
>
> Date: 10 Sep 99 10:24
> To: aquaponics@townsqr.com
> Subject:
>
>Was read at 10:48, 10 Sep 1999.
Mike - I get one of these messages for every one of your posts to the group.
Is it a setting in your computer that can be changed? It's not critical,
but it does add to the volume I have to read.
Glad to see that your system is getting up and running, and I'm also glad
you're able to use the group. Don't forget to change your subject line to
reflect the topic you're on.
Paula
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
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Subject: Re: RCPT:
From:
Date: Fri, 10 Sep 1999 10:56:30 + 5 EST
Paula - will change that - never occurred to me - hope what I am about to do
works!
Thanks!
Mike
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Subject: Re: RCPT:
From: S & S Aqua Farm
Date: Fri, 10 Sep 1999 11:08:39 -0500
Apologies to the group - so much for MY paying attention to headers.:)
Paula
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| Message 15 |
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Subject:
From:
Date: Fri, 10 Sep 1999 12:19:21 + 5 EST
Anyone know where I can get catfish for use in a recirc system here in
upstate ny?
mike
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| Message 16 |
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Subject: Re: Evaporative cooling
From: Ronald Polka
Date: Fri, 10 Sep 1999 10:25:25 -0600
At 02:52 PM 9/10/1999 +0100, Barry Thomas wrote:
>I meant that only the 'cold end' of your dehumidifier should go inside the
>greenhouse with the warm bits outside. So the dehumidifier should help lower
>internal temps directly as well as indirectly via evap cooling(?).
>
>Or is this what you meant by an air conditioner? I live in the UK -
>knowledge of these devices is rarely a top priority. :)
>
>Also occurs to me that a reduced RH should increase transpiration. Might the
>plants themselves not act as coolers? The energy to change the the state of
>the water in the plants from liquid to gas must come from somewhere?
>
>
>More rapidly than when powering large exhaust fans? Also, the large volumes
>of air use by fans must make any other form of atmosphere control (CO2
>enrichment, filtration etc) very difficult. Might the
>performance/reliability enhancements potentially available from a more
>closed GH not offset the extra costs?
>
>I'm not, in this or other posts, trying to say 'do it this way' or 'this is
>the way things are'. I assume these ideas have already been thought of and
>discarded. Just trying to understand why. :)
>
>Barry
>barrythomas@btinternet.com
>
Barry
I will take a guess on this one but I believe the coefficient of
performance on a dehumidifier is not very good, it will not be a very
efficient use of the electrical power. The bottom line here is to cool
economically. Dehumidifiers run on a refrigerant cycle which is inherently
inefficient if it is air coupled. The cost of running a dehumidifier that
would be sized large enough is probably prohibitive.
The mass of air that typically moves through the greenhouse is quite
large. To give a numerical example I recently sized fans and evap cooling
for a commercial range that used gutter connected houses. The volume of
each 22' x 128' bay was 16,900 cfm (ft3/min). The air flow rate required
for cooling was 36,700 cfm, that is more than two air changes per minute.
The mass of the air moving through this greenhouse bay at the design
location is 2,300 lb per minute. This large mass transfer is what makes
cooling possible in the greenhouse. If evaporative cooling is not
pschyrometrically feasible due to high relative humidity than the mass of
the air movement through the greenhouse must be increased because the inlet
temperature cannot be decreased.
Temperature control must always come before CO2 control because rapid temp
swings will cause more problems than reduced CO2. The primary reason for
CO2 enrichment is to restore depleted CO2 levels in a sealed greenhouse
that occur when the sun is shining and the house is cool enough so it
doesn't yet need venting. When photosynthesis causes the CO2 level to drop
to 100 ppm growth will nearly stop. CO2 enrichment enables high growth
rates when the greenhouse doesn't need venting. It can only be practical to
inject CO2 into a greenhouse during fan operation if a CO2 source exists on
site that is venting to the atmosphere already. These are specialized
conditions that the hobbyist never sees. This can occur when large
greenhouse ranges are paired with industrial processes or power plants, or
if the range is using geothermal energy for heat and the geothermal fluid
is stripped of its CO2 for corrosion control.
What it really boils down to is if one is having problems with controlling
heat in a high humidity location in an existing stucture the most practical
solution is to size up the fans and move more air through the greenhouse.
Ron Polka
Southwest Technology Development Institute
New Mexico State University
Box 30001, Dept 3SOL
Las Cruces, NM 88003
rpolka@nmsu.edu
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| Message 18 |
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Subject: Re: Re: Evaporative cooling
From: "Barry Thomas"
Date: Fri, 10 Sep 1999 18:24:39 +0100
Hi Mike,
If I gave the impression I have some big commercial operation, I'm sorry -
I haven't. My own small experimental system is Hydro only - no fish until
I'm totally confident about the plants.
I like your idea of moving the heat from the GH to the fishtank and agree it
should work better if heat loss from the tank happens somewhere other than
the GH though it might make things tricky during cold weather(?).
What kind of backup cooling do you have? I would find this 'hard' link
between GH and fish a little scary without some other way. What happens, for
instance, if during a time of unexpectedly hot weather, the fishtank temp
hits maximum and GH temps are still climbing? Boiled fish? Roast veg? Or
backup kicks in and saves the day?
How big is your GH compared to fishtank?
Just the thoughts of an amature...
Barry
barrythomas@btinternet.com
> Barry,
> Just a thought.......
>
> If your'e raising fish in your greenhouse (or even if you are not it might
work better for you). I am a
> teacher in Upstate NY and we are trying to "kill two bidrds with one
stone" on the heating/cooling
> end of things. If you are able to sink the "hot" end of the air
conditioner in a fish tank (large) you
> would be able to heat your water for fish growth and still benefit from
the cooling in the house. This
> may be difficult and may not be the recommended way, but it works for us.
Just have to lengthen
> the lines on your AC unit.
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| Message 19 |
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Subject: Re: pH Problems
From: "William Brown"
Date: Fri, 10 Sep 1999 06:31:42 -1000
I use potassium silicate to adjust pH and found an interesting side affect.
The EC goes way up when adding extra potassium to the nutrient solution. So
I would caution you to adjust EC/CF before adding extra potassium which has
a high electrical conductivity compared to other elements.
William Brown mahiwai@cmpmail.com
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| Message 20 |
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Subject: Re: Re: Evaporative cooling
From:
Date: Fri, 10 Sep 1999 14:29:45 + 5 EST
Ok - now i understand what we are talking about......
We are using our systems solely for heating our water for our fish.
Luckily, we have a refrigeration
specialt's wife on our faculty here at school and get a lot of "gratis" work
done. Our rig is as follows:
1. If we need cold water for fish (trout, salmon, etc...) we put the "cold"
coil in the tank and put the
"hot" coil in a 55 gallon plastic drum filled with water (more or less as a
heat sink). The water that is in
the drum is agitated by an airstone, so some evap cooling takes place. When
the water in the drum
gets too warm (110-125 degrees F) we open the drain on the bottom zand flush
it about 1/2 out -
then refill the drum with cooler water. Works great! In fact, sometimes we
get a thin coat of ice on
the tank water.
2. If we need warm water, we just switch the coils from tank to drum and
drum to tank. This makes
the drum "cold" and we don't have to worry about it if it freezes up too
much. The "hot coil" is in the
fish tank and works great - warms the water to the perfect tilapia and
tropical species temperature.
3. This year's big experiment is to split the colis into two separate fish
tanks and run a cold culture
(trout) in one tank and the warm coil for tilapia in another tank. IN
THEORY (and we all know how
that works...) it should swap heat and cold back and forth to do double
duty. Time and a few dead
fish will tell.
We have had awesome success with our aquaponics set-up. We germinate and
harvest in about
2/3 the time the seed packages say and have more pesto sauce from successful
basil growth than
we know what to do with. Also, although it may not be recommended, garlic
is going absolutely
CRAZY in our nodes - can't stop it from growing although we had concerns
about root veggies
rotting on us in such a moist environment.
In response, our greenhouse is not completed yet. Our students raised
nearly $40,000 last year
for this greenhouse and there dreams are now about to be built. We are set
to begin construction
of a 30X40 house in the near future.
Sorry this is totally irrelevant to your needs - but other may appreciate
the info!
Mike
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Subject: Re: Re: Re: Evaporative cooling
From: "Frank Stancato"
Date: Fri, 10 Sep 1999 14:59:23 -0400
Mike, sounds like a nice system. But unfortunately I am at a loss as to the
difference between the cold and hot coil? Could you please elaborate.
Thanks,
Frank
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Subject: Fwd. New product requests
From: S & S Aqua Farm
Date: Fri, 10 Sep 1999 15:59:01 -0500
Adriana sent this to our address, but I believe it was meant to go to the
list. Paula
-----------------------------
>Date: Fri, 10 Sep 1999 16:50:06 -0400
>From: Adriana Gutierrez & Dennis LaGatta
>To: S & S Aqua Farm
>Subject: New product requests
>
>Hi Gail,
>My smallest customer (and one of my favorites) has asked me to grow
>tsome special products for her and I have a few questions fromanybody
>who has experience with them.
>
>PEA SHOOTS (sprouts?) - I have not been able to locate any seeds for pea
>shoots and have never grown sprouts outside my kitchen. Can you help me
>with:
>
>1. Seed supplier - Johnny's and Ornamental Edibles don't carry them
>2. How do you grow them and how long does it take?
>3. Yield - how much seed is required to produce 1# of shoots?
>4. What kind of special post-harvest handling is required?
>5. Do you recommend any special peckaging?
>
>PURSLANE, SALAD BURNET, TREVISIO RADICCIO
>1. Can these be broacast densly as you would salad mix or should the
>plants be spaced farther apart?
>2. Can you cut and come again? How many cuttings before you have to
>re-seed?
>3. How is it harvested - leaves, cuttings?
>4. Any special handling requirements such as cold sensitivity?
>5. Will they grow in our warmer climate - for the next 6 months our
>highs will be in the 80's.
>
>Any suggestions would be greatly appreciated.
>
>Adriana Gutierrez
>Green Cuisine
>Sarasota, Florida
>
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
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| Message 23 |
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Subject: Re: Evaporative cooling
From: "Barry Thomas"
Date: Fri, 10 Sep 1999 22:42:02 +0100
Hi Ron,
Many thanks for your detailed post - heaps of info there to think about.
A few things for the moment though...
> I will take a guess on this one but I believe the coefficient of
> performance on a dehumidifier is not very good, it will not be a very
> efficient use of the electrical power. The bottom line here is to cool
> economically. Dehumidifiers run on a refrigerant cycle which is inherently
> inefficient if it is air coupled. The cost of running a dehumidifier that
> would be sized large enough is probably prohibitive.
I'm sure you're right but a dehumidifier in a fairly closed GH would have
several effects: Direct lowering of air temperature. Reduced humidity
giving greater transpiration and reduction of some diseases/fungi/moulds
and (possibly) increasing the plants ability to cool themselves. Another,
which could be of importance in some regions, is that you should be
able to recover almost all the water that would normally be lost through
transpiration/evaporation - could be a significant saving if you have to
get all your water through eg an RO unit?
> The mass of air that typically moves through the greenhouse is quite
> large. To give a numerical example I recently sized fans and evap cooling
> for a commercial range that used gutter connected houses. The volume of
> each 22' x 128' bay was 16,900 cfm (ft3/min). The air flow rate required
> for cooling was 36,700 cfm, that is more than two air changes per minute.
> The mass of the air moving through this greenhouse bay at the design
> location is 2,300 lb per minute. This large mass transfer is what makes
> cooling possible in the greenhouse. If evaporative cooling is not
> pschyrometrically feasible due to high relative humidity than the mass of
> the air movement through the greenhouse must be increased because the
inlet
> temperature cannot be decreased.
So, in this example, you must push more than 60000 cubic metres
of air, weighing over 60 tons through each bay of this GH per hour?
Sounds like fairly serious energy use. :) Especially when your plants
get tall enough to act as a baffle. Also, this much air must act as
quite a conveyor belt for pests...(?)
> Temperature control must always come before CO2 control because rapid temp
> swings will cause more problems than reduced CO2. The primary reason for
> CO2 enrichment is to restore depleted CO2 levels in a sealed greenhouse
> that occur when the sun is shining and the house is cool enough so it
> doesn't yet need venting. When photosynthesis causes the CO2 level to drop
> to 100 ppm growth will nearly stop. CO2 enrichment enables high growth
> rates when the greenhouse doesn't need venting. It can only be practical
to
> inject CO2 into a greenhouse during fan operation if a CO2 source exists
on
> site that is venting to the atmosphere already.
But that was the point I was trying (badly) to make. Increasing the CO2
level
is almost impossible in a GH that must have this kind of throughput of air.
If
you were able to greatly reduce this throughput, enhancements like this
become available - increasing yield and system viability.
> These are specialized
> conditions that the hobbyist never sees. This can occur when large
> greenhouse ranges are paired with industrial processes or power plants, or
> if the range is using geothermal energy for heat and the geothermal fluid
> is stripped of its CO2 for corrosion control.
I would _really_ like to see a system like this. :)
> What it really boils down to is if one is having problems with controlling
> heat in a high humidity location in an existing stucture the most
practical
> solution is to size up the fans and move more air through the greenhouse.
Again, I wouldn't argue with you. It just seemed to me that if an
alternative
method of cooling could be used, the amount of air flowing through the house
may be reduced to the level actually required by the plants. Maybe low
enough for some level of filtration at the inlet (probably a bit much to
expect
a bacterial filter but something insect proof so you're not, say, wafting
clouds of aphids over your plants) combined with a slight positive internal
pressure would increase security against pests. Also, any predators added
to the house are more likely to stay there and be waiting for those which do
make it inside.
At the exhaust, further water recovery could take place.
Is it not possible that all these (plus several more I'm sure I've missed)
potential gains may outweigh the costs?
I know there are a lot of ifs and maybes in all this but if only ever looked
at what is possible now...
Thanks again,
Barry
barrythomas@btinternet.co
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| Message 24 |
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Subject: Re: Evaporative cooling
From: "Barry Thomas"
Date: Sat, 11 Sep 1999 01:03:29 +0100
Hi Mike,
> Sorry this is totally irrelevant to your needs - but other may appreciate
the info!
Actually, this could be exactly what is needed. How does this sound:
A while back there was talk on the list of using a long piece of
water-filled tubing formed into two 'coils' for cooling. One coil was
distributed around the inside of the GH, the other buried in the ground. The
water was pumped around the tubing, transferring heat from greenhouse to
ground. One problem with this is that the ground often isn't a good heat
sink. Maybe your idea could be applied to this? If you altered things so
that you kept the loop inside the GH and had a large tank of water outside,
the two could be bridged using the kind of heat pump you describe. The cold
coil is placed in a small tank inserted into the large GH loop and the hot
coil in the large external tank. During the day, heat is transferred from GH
to tank. At night, the hot water in the tank could be wasted or, if needed,
an additional heat pump connected the other way around could transfer heat
back into the GH. Ron pointed out that air-coupled refrigeration wasn't very
efficient. This way, at least one side is liquid-coupled, could this raise
efficiency enough to be worthwhile?
It seems possible that the large GH loop could be kept at a lower temp than
would be possible using the ground as a sink, maybe even low enough for
condensation to form? Might be able to arrange things so that you get a
dehumidifier / water recovery from the same hardware?
Does this sound viable to you? Ron or others?
Thanks for the info and good luck with your project - though what you've all
achieved so far makes me think you probably won't need it. :)
Barry
barrythomas@btinternet.com
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| Message 25 |
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Subject: Free Guide to Building a Cooler!!!!
From: Mike Strates
Date: Sat, 11 Sep 1999 11:34:24 +1000
On Fri, Sep 10, 1999 at 02:59:23PM -0400, Frank Stancato wrote:
> Mike, sounds like a nice system. But unfortunately I am at a loss as to the
> difference between the cold and hot coil? Could you please elaborate.
I beleive he is talking about a slightly more complex version of an external
evaporative heat exchanger. These devices, as I've explained to fellow
greenhouse lovers numerous times are great -- because they DON'T add
moisture to the greenhouse atmosphere and don't need a lot of moisture to
work properly. In fact, they TAKE moisture from the greenhouse -- the little
droplets of water form on the heat exchanger coil and eventually drip into
the pond.
Mike's Passive Evaporative Cooler
*********************************
Copyright (C) 1999, Mike Strates
FOR THE SOLE USE OF THOSE ON THE AQUAPONICS EMAIL LIST
This evaporative cooler is designed to be based OUTSIDE of the greenhouse,
with only the tubing for the heat exchanger and maybe the overflow pipe
going in.
As such, this cooler does NOT add any humidity to the greenhouse and
functions quite well. It can lower the greenhouse temperature by around 15F.
Materials Required
==================
* 1x 44gal drum/barrel (or similar)
* supply of running, cool mains pressure water
* 1x large (around 5') length of PVC pipe
* lots of flexible garden hose
* 12 volt car fuel pump or other external well-washed pump
* 1x garden hose inline T-connector with flow control valves
* 1x garden hose inline control valve/tap
* power supply to run the pump
* drill
* silicone sealant or equivilant
Overflows and Clean Pipe
========================
The barrel has TWO overflows. Drill one overflow (call it the TOP overflow)
one foot from the barrel's top on the side of the barrel. Drill the second
overflow around 1/2 a foot lower than the TOP overflow.
Hence, you will have your TOP overflow and your BOTTOM overflow. You'll also
need your CLEAN PIPE. Drill your clean valve as close to the bottom of the
barrel as you can without damaging it.
All three holes which you have drilled for both the TOP and BOTTOM
overflows, plus the CLEAN PIPE must be just large enough to accomodate a
small length of garden hose.
Water Inlet Tube
================
A hole must be drilled in the CENTER or close to that of the barrel on the
top lid of it. This hole should be just large enough to accomodate a 5' high
length of PVC pipe. Insert this piece of pipe, ensuring it protrudes around
1' inside of the barrel and glue in place. There should be a 4' high statue
protruding from the lid.
Once dried, drill some small holes around six inches from the top of the
actual piece of pipe to allow air to flow into the pipe. Just drill some
holes all around, but don't go overboard.
Then, its time to fix up the end cap. Drill a hole into the middle of the
end cap, just large enough for a length of garden hose. You shall use this
later on in the text.
What We've Acheived
===================
Right now, you should have a barrel sitting up next to you with around 4' of
PVC pipe protruding from its lid, with some holes around the sides of the
piece of pipe around six feet from its top.
The sides of the barrel should have TWO overflow holes, realitively close to
the top of the barrel, and ONE drain hole, very close to the bottom.
You should also have a PVC end cap on the ground near you with a hole large
enough to accomodate a length of garden hose in it.
The Pump Assembley
==================
You'll need your well-washed 12 volt fuel pump, or an external pond pump
now. Using a length of garden hose long enough to reach to the pump's INLET
(if you stuff up, and cut too short of a length, use a garden hose joiner).
Glue one end of the pipe into the BOTTOM overflow (the SECOND overflow from
the top). Once dry, run the opposite end to the pump.
The Water Inlet Assembley
=========================
>From your hardware store, you'll need a garden hose T-connector WITH control
valves. These only cost around $2.95. You'll need to glue a length of garden
hose into the PVC end cap you made, only around 2' long. Once the end cap
has dried, press it onto the top of the large PVC tube you have protruding
from the top of the barrel.
Connect the end with only one connector of the T-connector (ie: the end
opposite the |_|) to the piece of garden hose coming out of the end cap.
Then, run a length of garden hose to one of the connectors on the T to a
nearby water tap, but don't turn on the water yet or muck around with the
valve on the connector. We'll discuss this later.
The TOP Overflow Pipe
=====================
The top overflow pipe will drip out water very slowly under normal
operation. You can place a length of garden hose here and direct this flow
anywhere you'd like, as long as it is lower than the barrel.. for this
reason, you may like to put this barrel on a roof or on stilts.
The DRAIN Pipe
==============
Buy a garden hose control valve (just an inline tap for garden hoses) from a
garden or hardware store. Affix a length of garden hose to the DRAIN HOLE we
made eariler at the very bottom of the barrel, and then to the inline tap.
You can then run a hose from the tap/valve to a nearby drain or just let it
fall on the earth.
The Pump Outlet/Heat Exchanger
==============================
Next, connect a length of tubing to the pump's OUTLET and direct it in a
coil like fashion into your greenhose for cooling. Bring the other end of
the pipe back and connect it to the SECOND T on the connector which goes up
to the large PVC tube and set its valve on the connector to FULL FLOW.
Additional Aeration
===================
If you want better performance, you can add additional airstones into the
barrel. This is beyond the scope of this document.
Getting it ALL Working
======================
Once everything is dry, set the valve on the T-connector which goes from the
mains water tap to the large tube to FULLY OFF/CLOSED. The second valve
which goes from the greenhouse's heat exchanger should be set to FULLY
ON/OPEN.
Go cautiously to the mains water tap, and give it a turn and make sure that
everything holds water while it is off. Then go over to the valve on the
T-connector and slowly turn it FULLY ON so that the barrel fills.
Once water begins to spew from the TOP overflow turn the pump ON, and reduce
the amount of fresh water going into the barrel using the T-connector's
valve until just a small trickle comes from the TOP overflow.
Measure the temperature of the barrels's water with a thermometer and check
it one hour later. You should also see fine water droplets condensing on the
tubing inside of the greenhouse.
Congratulations, you're done!
--
Mike "Skyfox" Strates ; www.croftj.net/~mstrates
Voice: (011) 613-9440-5778; Voicemail (US): 1-888-392-4832, ext: 2913058153
ICQ #47663425
"... and while you're at it, why not treat the pax to some zero
G's. Just knock the yoke right down the stoppers with one hand,
and after you've made a perfect recovery, advise all on board
that this terrible mishap was a result of clear air turbulence"
-- Mike's 101 Never-Fail Ways to get fired from United.
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| Message 26 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Need off grid advice
From: "grizzly"
Date: Fri, 10 Sep 1999 22:33:35 -0400
Hey are you related to Joe Nasmeth
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| Message 27 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Evaporative cooling
From: "grizzly"
Date: Fri, 10 Sep 1999 23:34:03 -0400
Hi,I have a few ideas on this subject,first on your shade cloth,if you will
leave a space between the cloth and your poly it will reduce heat gain thru
convection. Second,instead of using misters inside your greenhouse,run the
misters inside the dead air space between layers of poly,that way you can
cool the air around your greenhouse without increasing the humidity,the heat
inside the greenhouse will transfer to the cooler air inside the dead air
space,be sure to place vents at the lowest and highest points on the outside
layer of plastic only.Third,you can place misters above your shade
cloth,evaporation will cool the surrounding air.I just had another thought,I
have read many times about someones Poly being better,because it sheds
water,which inhibits light penetration,but so does shade cloth,I wonder if
you used a system like i'm suggesting,would you even need shade cloth?
Opinions welcomed. Griz
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