# Vivarium A/C Ideas?



## hypostatic

So, I've been thinking a lot lately about temperature regulation in vivs. If you devote an entire room to your frogs, then it probably makes sense to have dedicated A/C allocated to that room.

But what if you're just keeping a tank or two that need to be cooled? Or better yet, what if you want to keep two species that like it hotter/colder (pumilio/mantella) in the same room? In these cases, heating/cooling the entire room just isn't the best solution (or a solution that works for both problems).

So, I did a google search for "terrarium cooling" and here are some interesting results:

$10 Salamander Air Conditioner - Caudata.org Newt and Salamander Forum









This is a simple cooler full of ice-packs, attached to a terrarium with fans for circulation. Really cheap too! The only real downside is that the ice packs will eventually melt and need to be replenished.

Cooled terrarium for Venus Flytrap with a Peltier TEC (part 1) « Emanuelis' Blog













This solution is like adding an A/C unit directly to your viv! The video description for the youtube video says that with that setup they could maintain a daytime temperature of 77F, and a nighttime temp of 50F!

So, has anyone tried anything similar to this? Does anyone know how you could add some sort of temperature controller to turn on the A/C when things get too hot, and to turn it off when things get too cold?


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## Ghost vivs

That's cool. Literally... 
With a bigger and better cooler and a few more fans you could probably cool quite a few vivs in an emergency. Or cycle a whole collection for a few weeks ( hard to do in the south ). 

I think some testing is in order. 
Casper


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## Spaff

From what I've read, you need very strong peltier coolers to bring about that kind of cooling. There's a thread here in the plants section about plant suggestions for a cloud forest tank authored by Zach of Josh's Frogs that gives many cooling methods. I would start there for inspiration.


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## hypostatic

Spaff said:


> From what I've read, you need very strong peltier coolers to bring about that kind of cooling. There's a thread here in the plants section about plant suggestions for a cloud forest tank authored by Zach of Josh's Frogs that gives many cooling methods. I would start there for inspiration.


Thanks, I believe this is the thread in question:
http://www.dendroboard.com/forum/plants/77175-plants-cloud-forest-vivarium.html

I skimmed it to the end, and there's a lot of good possible ideas that have been posted in there. It doesn't look like any hardware progress was made though on an actual tank build....

Like, I'm looking at my window at my window AC, and I can't help but to think to myself -- why hasn't something similar and simple been made for vivs?

Edit:

Here's a video tutorial I found on how to make a peltier cooler for vivs:


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## SmackoftheGods

I'm working with central air so keeping a decent temperature isn't that hard. I double stack my tanks. Cold frogs on the bottom, hot frogs up top. This method suits my needs....


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## hypostatic

Here's a thread I found on orchidboards about a TEC cooled viv. Small viv, but it works apparently
Dend.Cuthbertsonii peltier cooling case. - Orchid Board - Most Complete Orchid Forum on the web !

And pics stolen from the thread:


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## Fantastica

This is interesting. I need something like this for an already established viv that I can't cut holes into. We keep a wood stove in the winter and it's practically impossible to regulate the temperature and keep it from going in the 80ls sometimes.


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## hypostatic

Yeah, that's one of the issues that I want to address -- temperature regulation. I'd like to have something that you can hook up to a thermostat and turn on automatically and cool the viv when needed. In the first TEC viv I posted you can even see the condensation on the glass from the cool air.

The TECs do look like they'd require the glass to be drilled however. The top and the bottom of the coolers need to be separated, and in the pics you can see that there is a piece of glass separating the two sides


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## hypostatic

Here's a nice thread about a fairly large viv (I believe the thread says its 4'X4'X2'), which the author manages to get down to 50F!

My new highland/ultra terrarium setup | Carnivorous Plants in the tropics


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## hypostatic

Sorry for all the boring posts -- they're mostly so I have a place to come back to with ideas. Also not bad for anyone else who wants some ideas 

Another successful viv:
Cooling a Vivarium


















A video from the author:





He uses a corsair liquid cooling system to help with cooling with the TEC


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## frogfreak

hypostatic said:


> Sorry for all the boring posts -- they're mostly so I have a place to come back to with ideas. Also not bad for anyone else who wants some ideas


Not boring at all! I've read every one. Keep em coming!


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## hypostatic

I just wanted to post some basic info and points of the TEC plates.

So, basically, they're heat pumps; they move heat from one side of the plate to the other. And there's some math/physics n stuff involved in there I guess, but this image illustrates the basics:










And from what I would think at first, you'd want something that looks sort of like this to cool the best, where the system is symmetrical:










A fan on both sides to equally draw in air to be heated/cooled on either side. But from what I've read, how much heat is absorbed on the cold side is limited by how much heat is released on the hot side (which makes sense I suppose). Therefore, when designing a TEC cooler you'd want to design the system as being disproportionately weighted on the hot side (i.e. two fans on the hot side, one fan on the cold side). This can be seen in the following examples:

Here there's a much larger heat sink on the hot side









You can see that the cool side has one fan here








While the hot side has two fans









Just a point I wanted to state that I've noticed. I've seen people say that they TEC plates don't work well enough to cool large spaces like terrariums, but in the cases where they DO cool them enough, this asymmetrical design seems to be critical in the system's success.


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## ivas

Not quite A/C, but I have thought about the possibility of embedding Phase-22 panels in the background to help stabilize temperatures.


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## diggenem

I found this a few weeks ago. It's a fairly large viv cooled by a freezer. Heres the full thread Cool vivarium - Orchid Forum by The Orchid Source


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## MELLOWROO421

Has anyone tried using ice water in a Repti-fogger and checking to see if it brought the temps down?


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## JPccusa

I have not tried because I doubt it would work. The fogger warms up the water AND the tiny particles (fog itself) would get to room temperature before having much of a cooling effect in the viv, I believe. It would be nice to learn I'm wrong.


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## MELLOWROO421

I thought it was an ultrasonic humidifier, which means it vibrates and causes a fog instead of heating the water. I don't think it warms the water up at all. 



JPccusa said:


> I have not tried because I doubt it would work. The fogger warms up the water AND the tiny particles (fog itself) would get to room temperature before having much of a cooling effect in the viv, I believe. It would be nice to learn I'm wrong.


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## JohnL814

I like the idea of running cold air through a small freezer. Has anyone tried running water through a small refrigerator with a small radiator in it. Run the cold water through the vivarium as a water feature with a pump and it should drop the temperatures in the vivarium. The temperature could be regulated with the thermostat in the refrigerator. I thought of this setup when I had Silverstoni; but I never was able to build it and try it. 

I heated aquariums in the 1990's with an aquarium heater (50W or 75W element) that was sitting in a water pool with a Duetto filter. The heated water was circulated through the vivarium. The temperature was regulated through the adjustable setting on the aquarium heater. This setup increased the humidity and temperature. It took a little trial and error to get the desired temperatures, but it worked great for years.


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## hypostatic

So, I feel another important concept for the whole AC idea is a thermostat or temperature controller. No matter what the actual cooling source is, it's important for it to be regulated so the temperature doesn't drop too low.

This seems like it's fairly simple and would fit the bill:


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## Epiphile

Those simple controllers have worked well for me; I have one that I'm using to control humidity in a propagation tent.


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## Dendro Dave

MELLOWROO421 said:


> I thought it was an ultrasonic humidifier, which means it vibrates and causes a fog instead of heating the water. I don't think it warms the water up at all.


Well the vibrations as I understand it atomize the water, but the friction or whatever involved temporary heats the water substantially which is why the water jet will burn you close to the head of an ultrasonic fogger even if you don't actually touch the plate/transducer, but because of evaporative cooling (I assume) this water vapor rapidly cools and the super saturated air/fog gets chilled which is why the "fog" comes out feeling pretty chilly... or something like that 

The problem with using a fogger for cooling is that while it can be helpful, unless you set it up to work with a very large reservoir it will often need refilling, you must use very pure/distilled water or it will die due to mineral build up and other gunk, and then if you run it that much well your viv will be constantly fogged so you can't see anything unless you suck/blow all the fog out immediately (which probably would cut down on how well it cools the inside of the viv, but that much airflow would give you more evaporative cooling so maybe it would even out ). 

So in the end, it looks like it is ok for bonus cooling maybe...but not the greatest way to go for doing the whole job. Though I suppose you could build some kinda swamp cooling system for a viv and some how get it to work, but seems like TEC or compressor based cooling is going to be the most efficient short of justing having a chilly room, or being able to have a window or portable AC unit blow right on the glass most of the time.


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## hypostatic

I've also though about a compressor based system, but it seems hard to find out more info about micro-compressors. They're definitely out there, but I can't seem to find much information about the price, which is never a good indicator...


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## Charlie Q

I am no expert in viv cooling, but I am an engineering student, and I have done some extensive study into heat transfer. it seems to me, if the temperature regulation and the humidity systems were combined, you could make the whole system more efficient. For instance, if the tank was set up such that when its temp got higher than the temperature in the room, the hot air would rise out of the tank through high ventilation holes, and would suck air through lower ventilation holes and simultaneously through a wet cloth media which was getting a constant supply of water (from the bottom of the tank, it will wick up wool) then 2 things will happen. first, the hot air will be escaping, taking some humidity along with it, the incoming air will be cooler, and further cooled by the swamp cooling effect, which replaces the humidity at the same time. when the temp re-stabilizes in equilibrium with the surroundings, the air will stop rising. if you want to have the tanks be at a different temp than its surroundings, this setup would run into problems. however, you could use fans to force the cycle which would probably be effective, but you would lose much more water that way.

-Charlie Q


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## p.terribilis

Charlie Q said:


> cooled by the swamp cooling effect


Love that idea. Any ideas on how to make a mini swamp cooler?


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## Judy S

fascinating thread...subscribed for reference...thanks for the research...


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## hypostatic

Charlie Q said:


> I am no expert in viv cooling, but I am an engineering student, and I have done some extensive study into heat transfer. it seems to me, if the temperature regulation and the humidity systems were combined, you could make the whole system more efficient. For instance, if the tank was set up such that when its temp got higher than the temperature in the room, the hot air would rise out of the tank through high ventilation holes, and would suck air through lower ventilation holes and simultaneously through a wet cloth media which was getting a constant supply of water (from the bottom of the tank, it will wick up wool) then 2 things will happen. first, the hot air will be escaping, taking some humidity along with it, the incoming air will be cooler, and further cooled by the swamp cooling effect, which replaces the humidity at the same time. when the temp re-stabilizes in equilibrium with the surroundings, the air will stop rising. if you want to have the tanks be at a different temp than its surroundings, this setup would run into problems. however, you could use fans to force the cycle which would probably be effective, but you would lose much more water that way.
> 
> -Charlie Q


Thanks for the input. I'm guessing you're imagining something like the first example I posted?










But instead of the air being circulated back into the cooler, it would be exhausted out into the room?


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## Dendro Dave

p.terribilis said:


> Love that idea. Any ideas on how to make a mini swamp cooler?


Uh that would basically be a reservoir with tube/roller covered in sponge or something that had fand blow over the wet parts after they were partially dunked in the water. Or more simply attack a box fill with water, and a fan that blew onto the water and a hose or vent into the main viv....because that evaporative cooling is the same thing a swamp cooler does. Need a good size reservoir in either version though to avoid constantly topping it off


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## Dendro Dave

hypostatic said:


> I've also though about a compressor based system, but it seems hard to find out more info about micro-compressors. They're definitely out there, but I can't seem to find much information about the price, which is never a good indicator...


Ya I'd probably cannibalize a dorm fridge for the stuff, or buy a large enough fridge to turn into your viv. Install a second ceiling with your lights and stuff that is flush when the door shuts so frog don't get up there. Kinda like the guy with the duel TEC system did in one of the examples.


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## froggy_skibum

An idea I've had for awhile is to plumb a false bottom and water feature into a sump for a total volume of 5~8 gallons and then use an iceprobe chiller in the sump to chill the water and a fan blowing on the water feature for evaporative cooling and to move cold air around to cool the entire vivarium
http://http://www.marinedepot.com/chillers_coolworks_iceprobe-ap.html


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## Charlie Q

Dendro Dave said:


> Need a good size reservoir in either version though to avoid constantly topping it off


This is completely dependent upon the temperature difference between the tank and its environment. If there is a huge difference, then yes, it will run dry. if it is only varying by a few degrees, normal misting should replenish the water loss. 

Additionally, it seems that most people use vented vivariums. this method simply uses the natural rise of the air to pull in air through the wool. and keeps it humidified. 

I attached a picture of how i would set it up.


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## Dendro Dave

Charlie Q said:


> This is completely dependent upon the temperature difference between the tank and its environment. If there is a huge difference, then yes, it will run dry. if it is only varying by a few degrees, normal misting should replenish the water loss.
> 
> Additionally, it seems that most people use vented vivariums. this method simply uses the natural rise of the air to pull in air through the wool. and keeps it humidified.
> 
> I attached a picture of how i would set it up.


That is an interesting design. Might be useful for a few degrees cooling.


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## Charlie Q

Dendro Dave said:


> That is an interesting design. Might be useful for a few degrees cooling.


If you read my original post, thats all i want it to do. Maintain equilibrium with the tanks's surroundings.


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## Dendro Dave

Charlie Q said:


> If you read my original post, thats all i want it to do. Maintain equilibrium with the tanks's surroundings.


Sorry I skimmed some stuff. I think the ambien was kicking in when I wrote my last couple replies, hence the need for more editing of spelling, and I could have probably been more coherent in some of those posts


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## Charlie Q

All good. one problem i see in significantly cooling a vivarium is that the most thermal mass is the water in the viv. with many systems, you could cool this section and the rest should take care of itself. however, in a vivarium, this high concentration of thermal mass is on the bottom, and separated by a thick layer of insulation (substrate). this is challenging because, unless you have a water feature circulating the water, all the heat will rise to the top, and leave the cold on the bottom. 

I wonder how well you could cool a tank with a system of cooling coils laid out on the bottom to cool the water, and a mister that draws from this cooled reservoir.


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## Dendro Dave

Charlie Q said:


> All good. one problem i see in significantly cooling a vivarium is that the most thermal mass is the water in the viv. with many systems, you could cool this section and the rest should take care of itself. however, in a vivarium, this high concentration of thermal mass is on the bottom, and separated by a thick layer of insulation (substrate). this is challenging because, unless you have a water feature circulating the water, all the heat will rise to the top, and leave the cold on the bottom.
> 
> I wonder how well you could cool a tank with a system of cooling coils laid out on the bottom to cool the water, and a mister that draws from this cooled reservoir.


Ya, though I think since our substrate is always moist the problem is mitigated to some extent. So in a way the water works for us. I bet it would actually be harder to cool and hold the cooler temps in a much dryer tank.

*And in other news...*

I've done some more brain storming and came up with some other rough concepts for cooling...

1. hook and ice maker assembly up to your power and home plumbing and let the air and/or melt water run out through a drainage hose into the vivs pond/drainage layer.
Icemaker kit (may need additional parts and expertise) 




Mini freezer size of mini fridge, colder but more expensive option http://www.amazon.com/Haier-HUM013EA-CU-FT-COMPACT-FREEZER/dp/B0019CV6OW/ref=sr_1_19?s=kitchen&ie=UTF8&qid=1377713394&sr=1-19

Here is an article about the nucool tech vs standard thermoelectrics...
ApplianceMagazine.com*|*<b>Web Exclusive:</b> Engineering Big Ideas into Small Spaces*-*Refrigeration Systems & Compressor Technology

I think the compressor or nucool tech based mini fridges are probably one the cheapest and likely to be effective solutions. Under 100 for the fridge often, and tom's pumps are 15-20 each I think, and a few dollars for the little aquarium tubing and misc supplies. I'll assume you have a drill...shouldn't be to hard to get 2 holes through the door and not actually damage the fridge's workings. I think one of the key elements will be finding a container that fills the inside of the fridge as much as possible. Maybe even going so far as to build or modify something to fit. You should be able to top the system off by just adding water to the viv's pond or drainage layer. A little slack in your lines and space in the fridge and maybe you'd get some use keeping some beer cold too  Basically you'd just have this box sitting next to/behind/below or near your viv (closer the better).

I'd bet though for most tanks under 40 gal you could probably pop the door off the fridge, drill a hole or several through the glass at floor level, with tubes running from bottom of fridge into viv (seal them so stuff doesn't climb into the fridge) and you'd get plenty of cooling for most stuff. Could go the extra mile and use foam insulation boards to insulate the bottom/sides/back of tank wherever the fridge isn't to help with efficiency. Might even be able to set up the venting lines in the water/drainage column so there is water exchange from the viv into the bottom of the fridge if your seal is good enough. $70+ misc supplies/tools


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## SpaceMan

I gave the Peltier (thermoelectric) cooling idea a shot last night on an empty 20 gallon aquarium with 1/4" thick glass. I had the parts laying around and wanted to see if there was any measurable effect. 

The TEC I used was small and maybe 150W. I attached heat sinks to both sides with fans for forced convection. I then placed this device through a piece of styrofoam such that the cold fan and heat sink were inside the aquarium and the warm heatsink and fan were isolated from the aquarium.

I hooked up a thermometer and hydrometer to my computer and began logging data. I then turned the device on and waited. Over a period of about 30 minutes I got a change in temperature of only 1 degree (28.2C to 27.2C) or 1.8 degrees F. 

I know it can be done from other posts in this thread, but it probably requires better fans, heat sinks, and most importantly, insulation. After all, a lot of mini fridges are powered by these devices. 

I don't think I added anything new to the discussion, but I just thought I would share my success or lack thereof.


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## Charlie Q

One of the issues with this A/C approach is that before it cools the air, it must remove the humidity. This is because water vapor will change phases at a constant temperature. so any heat (energy) removed from the tank will be removed in the form of a vapor to liquid phase change. After that, the energy can further be removed, this will be felt in the form of a temperature drop. A vivarium is not a good application for a traditional A/C unit because you do not want to lose your humidity.

In my mind, the only way to cool the viv is to cool the water itself. so you would need to collect the condensation and spray it back into the tank at a cooler temperature. the heat in the tank will be absorbed by the water vapor, and the temperature will drop as molecules change phase.


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## Dendro Dave

I wonder about a duel water/air system similar to my fridge with toms pump idea, exchanging the warmer water for cool water... but adding a 2nd phase where the cold water being pumped into the tank goes into a swamp cooling type setup with like a thin foam membrane that sponges up water and has a fan blowing on it and then an output hose that pumps that cool air (and it would be humid air wouldn't it?) into the viv, while also further cooling the water being pumped into the viv (or would that fan blowing on it actually warm the water?) I think the key is the swamp cooler box would have to be well insulated, and you could add an air pump to the inside of the fridge so it is pumping cold air into the swamp cooler box for the fan to blow. 

I guess instead of the swamp cooler box, you could just go the more direct and simpler route and have the top of the reservoir in the fridge open (might work pretty well even if your water reservoir was completely sealed up) and intake/output lines for an air pump drilled into the fridge door similar to the toms pump setup... So basically the exact same principle, only one is using the cold water chilled by the fridge, the other uses the cold air chilled by the fridge since it is unlikely you'd have a completely form fitting reservoir, might as well take advantage of those air pockets. You could insulate the air lines to limit loss of chilliness in the air, like with GS foam around them, or some kind rubber insulating sleeve.

You may need a tiny vent to allow more air into the fridge so you don't end up creating a vacuum chamber, but seems like that may be a way to squeeze even more cooling power out of the fridge unit...as long as it didn't cycle so fast that the fridge actually started loosing ground on keeping the water/air inside it cool. So a small/weak (possibly adjustable), air pump similar to how the toms pump is low flow might be a better option then a fan that facilitated to rapid an air exchange to get much cooling. 


Think that would work?


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## hypostatic

SpaceMan said:


> I gave the Peltier (thermoelectric) cooling idea a shot last night on an empty 20 gallon aquarium with 1/4" thick glass. I had the parts laying around and wanted to see if there was any measurable effect.
> 
> ...


Any chance you could post pics and tech specs of your build?


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## SpaceMan

Charlie brings up a good point that a traditional AC system is mostly unsuitable for a vivarium system. The Thermoelectric implementation wont dehumidify the air so long as the heat sink is large enough and the air flow is high enough that the temperature at the surface of the heat sink is not at or below the dew point. However, for very humid vivariums, it won't take much of a temperature drop to hit the dewpoint. Then, you have a lot of work to do. 

The energy involved in a phase change is significant and, as Charlie noted, occurs at a constant temperature. Thus you're pumping energy out of the system, but not heat. Moreover, if condensation is occurring on the heat transfer surface, then you begin to immediately lose effectiveness because the thermal conductivity of water is incredibly small as compared to say, Aluminum or Copper. 

With all that said, here are my 2 cents, and this has already been mentioned:
Use an small insulated cooler outside of the tank, and fill it with water that can be chilled. In fact, you can use a Peltier device to chill the water if you want. Then use pumps/mister to spray this water into the tank when needed. To increase the effectiveness of such a system, you would want to activate any vivarium vent fans to decrease the humidity as much as possible then immediately activate the cooling system. This would allow for evaporation of the mist when its sprayed, which, for the same reasons stated earlier, would cool the air, without increasing the temperature of the water. You could also circulate water in the tank to the cooling chamber if the system is being used a lot. 

I will add pictures of my sandwiched Peltier when I get home, but be warned, it's nothing special!


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## SpaceMan

Here is the cooling data:










Here was the messy setup: 









And here is the TEC sandwich:


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## hypostatic

Also, what type of TEC plate were you using? And what voltage/current? I've read that if they're not running at the correct voltage/current they'll perform sub-optimally.

OH, I am also very interested in your wiring scheme haha


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## SpaceMan

Good question and good question. This particular TEC I can't remember the model number. 

I have a few other TECs that are 12710s: Amazon.com: TEC1-12710 TEC Thermoelectric Cooler Peltier: Computers & Accessories

These are 154W if they're pulling their max current. I wasn't monitoring the current pull during this test, but the wires leading to the TEC get pretty hot (which is one reason I am not really a fan of this implementation). You really need some larger diameter wire than the 18 or 20 gauge wire if you're using a 154W TEC -- starting a fire sort of defeats the point of cooling. 

No wiring scheme, I just jury-rigged it to a spare PC power supply (300W). Fans were also connected to the 12V lines of this power supply.

Data was gathered using a DHT22 temperature/hydrometer wired to an Arduino Leonardo running some simple code. 

This was by no means a scientific test and if I do it again, I'll control things more precisely and do some replicates.


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## goof901

Since this thread has shifted to TEC I figured I might as well add my experience to this. Using a TEC hooked up to a duct I've been able to cool a 10 gallon viv 5 degrees F. The only downside I've seen from this is that the viv dries up much more quickly. However constant misting helps the temps even more. My TEC probably isn't even running at max efficiency because I am using a hardcore power supply from a computer room and I'm sure the amperage isn't as perfect as possible. My 2 cents.


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## SpaceMan

PC power supplies can supply plenty of amperage. Usually it's indicated on the side of the power supply. For example, this cheapo supply provides 30A on it's 5V line and 15A on its 12V line.


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## grabberorangestang

To go off of dendrodave, this is the idea that I am thinking of implementing. I am not sure if the TOM pump is strong enough though. Basically with the way my viv is setup I will draw water through air line tubing and run it to the pump and then from the pump into the cooler, from the cooler into the waterfall( I figure this would help disperse the temp) This makes the TOM pump never come in contact with the cold. What do you guys think? Good or bad? Im dealing with over 82 degree temps during peak of the day.


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## goof901

SpaceMan said:


> PC power supplies can supply plenty of amperage. Usually it's indicated on the side of the power supply. For example, this cheapo supply provides 30A on it's 5V line and 15A on its 12V line.


Yeah I don't remember the specific amperage cuz it was a while ago, but my power supply is something like 1 amp lower than my TEC. Not a huge amount, but it could affect the efficiency a little bit. My method wouldn't work so well for an orchid tank IMO because the cooler lowers the humidity a lot (i think, based on the leaves drying up in the tank) and that probably wouldn't be good for orchids...


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## Charlie Q

grabberorangestang said:


> To go off of dendrodave, this is the idea that I am thinking of implementing. I am not sure if the TOM pump is strong enough though. Basically with the way my viv is setup I will draw water through air line tubing and run it to the pump and then from the pump into the cooler, from the cooler into the waterfall( I figure this would help disperse the temp) This makes the TOM pump never come in contact with the cold. What do you guys think? Good or bad? Im dealing with over 82 degree temps during peak of the day.
> [/URL]


It would be more effective if the cold water was misted out into the viv, but i think that even the waterfall should take the edge off the heat. if the water is getting cool enough it will be hard for that kind of heat sink not to absorb some temperature. I wouldn't expect it to drop the temps too drastically, unless you have a LOT of water in the system. the more water you have, the more thermal capacity, the more thermal capacity being cooled, the more heat you can remove from the viv.


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## grabberorangestang

Charlie Q said:


> It would be more effective if the cold water was misted out into the viv, but i think that even the waterfall should take the edge off the heat. if the water is getting cool enough it will be hard for that kind of heat sink not to absorb some temperature. I wouldn't expect it to drop the temps too drastically, unless you have a LOT of water in the system. the more water you have, the more thermal capacity, the more thermal capacity being cooled, the more heat you can remove from the viv.


Could I put a resevior in the fridge and have a mistking pump it into the tank? Could the mistking pump handle 35-40 degree water? Would the cold water affect the frogs?


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## Charlie Q

grabberorangestang said:


> Could I put a resevior in the fridge and have a mistking pump it into the tank? Could the mistking pump handle 35-40 degree water? Would the cold water affect the frogs?


I can only speak from an engineering point of view, and I do not know how the cold water will effect the frogs, but here is what i think:

misting cold water into the viv is probably the most effective way of reducing the temperature. i do not know about the specifications of a mist king system, but i see no reason for the pump not to be able to handle 35-40 degree water. as long as it isn't freezing completely. (pay attention to it though, as this temperature of water is probably forming little ringlets of ice on the molecular level, i don't think this should be a problem, but monitor it. most likely the pump itself will add some heat to the fluid and you should be fine). 

as soon as the cold water is misted into the tank, it will start absorbing energy from the tank. the finer the mist, the more rapidly this will take place. so i would think that a well designed system should be able to mist the water in, cool the tank, and not harm the frogs. 

an additional note on this though, if the air in the tank is really high, it will be harder to evaporate the mist, and you might have to aim for a slightly warmer temp so that the frogs don't get doused with freezing cold water.

again, i wish i know more about frogs and their abilities to survive in different conditions, but i do not. I how that the system works out, and let us know if it is successful or not.

-Charlie Q


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## Dendro Dave

grabberorangestang said:


> To go off of dendrodave, this is the idea that I am thinking of implementing. I am not sure if the TOM pump is strong enough though. Basically with the way my viv is setup I will draw water through air line tubing and run it to the pump and then from the pump into the cooler, from the cooler into the waterfall( I figure this would help disperse the temp) This makes the TOM pump never come in contact with the cold. What do you guys think? Good or bad? Im dealing with over 82 degree temps during peak of the day.


Ya that is basically the setup I had in mind, but you could increase efficiency a little by making sure the tubes are insulated with some kinda rubber sleeve, or if you don't mind it looking ghetto coat them in Expanding foam. You might even go so far as encasing the Tom's pump in expanding foam (or just mounting it in the fridge), or some kind of cooler box, this way you've eliminated yet another point at which you may loose some of the chill in the water. 

Then you could try out the 2nd phase, and basically do the exact same thing over again only with an air pump, so you're pumping both the cold water, and cold air from the fridge into the viv... Insulate those lines/pump also. The Tom's pump should be powerful enough, they are a "lifting" pump and work to about 3 feet high. You can also set 2 onto the same intake line and outake line with the right valves/splitters and crap (sold for air lines), and that would basically double the GpH and increase the lifting power. I think though their very low flow is going to be a benefit since at 3 GpH they will exchange all the water in the most vivs fairly quickly but give it adequate time to chill inside the fridge. 

I think most people have been using standard pond/waterfall pumps with much higher GpH ratings, and essentially they flush water through the system so fast it never gets to chill as much as it could, and that is why they find they have to make these coils of stainless steel tubing, or rubber hose in their reservoir to increase surface area and get the water cooled enough as it goes through the system... and chances are they don't need 50 gph flow rate or whatever. I could be wrong but I think people are shooting themselves in the foot by using pumps with to high a flow rate in these type cooling systems. I'm not a math guy but I bet there is some equation that would give us ideal flow rate/to chilled water volume ratio or something.

*Note:* Tom's pump's red connection points are fragile, be careful putting line on and especially pulling it off... It is helpful I found to install 2 short pieces of line, fill the red connection point area up with silicone, then attach your lines to your short (1ft long?) connection lines so you can hook up/unhook lines without having to pull on those red connection points. Otherwise It is really easy not to pull perfectly straight and end up breaking them off.

Also Tom's are very low flow, so you're waterfall will not be roaring, but decent enough probably. A dual or tri tom's system would increase flow and lifting power but might cycle the water to fast to get it cooled...hard to say, something to play with and see I guess. 



Charlie Q said:


> It would be more effective if the cold water was misted out into the viv, but i think that even the waterfall should take the edge off the heat. if the water is getting cool enough it will be hard for that kind of heat sink not to absorb some temperature. I wouldn't expect it to drop the temps too drastically, unless you have a LOT of water in the system. the more water you have, the more thermal capacity, the more thermal capacity being cooled, the more heat you can remove from the viv.


That is an excellent point. Misting out that chilled water may do wonders since it is diffused into the air immediately. Only issue I see with that is it might be difficult to do that enough to get the cooling you need all day, without flooding the tank. You might need a fast draining substrate, a drilled tank (The tom's pump version can actually be used in a tank not drilled since it pulls water from the water column and just puts it right back in. You can run the lines into the top of tank and hide them), and maybe plants that can cope with a lot of water.

Now I don't see any reason why you couldn't use that water reservoir for your mist system, misting once or twice a day, but also have the toms pump setup running all day in between misting periods to maintain the chill. You're just going to have to top off your fridge reservoir and it might be beneficial to setup another tom's pump and some kinda auto top off system for that using water from another reservoir (I guess you could chill that too!)



grabberorangestang said:


> Could I put a resevior in the fridge and have a mistking pump it into the tank? Could the mistking pump handle 35-40 degree water? Would the cold water affect the frogs?


Ya I think that is a good idea if used in conjunction with the tom's pump setup. Assuming the pump can handle the cold and doesn't heat up the water to much (maybe mount the pump outside fridge, but have the intake line going into fridge, and insulate the output line into viv. That way the pump itself doesn't contact the chilled water in the fridge (That possible with mist king pumps?, Maybe build a small intermediate stage reservoir outside and insulate if need be?). I don't know how much they'd heat the water, probably not enough, especially in the fridge to handicap us to much. 

Marty is the guy to ask about their cold tolerance. My guess is if the water doesn't freeze they'd be fine. He may not guarantee them in those conditions though. 



Charlie Q said:


> I can only speak from an engineering point of view, and I do not know how the cold water will effect the frogs, but here is what i think:
> 
> misting cold water into the viv is probably the most effective way of reducing the temperature. i do not know about the specifications of a mist king system, but i see no reason for the pump not to be able to handle 35-40 degree water. as long as it isn't freezing completely. (pay attention to it though, as this temperature of water is probably forming little ringlets of ice on the molecular level, i don't think this should be a problem, but monitor it. most likely the pump itself will add some heat to the fluid and you should be fine).
> 
> as soon as the cold water is misted into the tank, it will start absorbing energy from the tank. the finer the mist, the more rapidly this will take place. so i would think that a well designed system should be able to mist the water in, cool the tank, and not harm the frogs.
> 
> an additional note on this though, if the air in the tank is really high, it will be harder to evaporate the mist, and you might have to aim for a slightly warmer temp so that the frogs don't get doused with freezing cold water.
> 
> again, i wish i know more about frogs and their abilities to survive in different conditions, but i do not. I how that the system works out, and let us know if it is successful or not.
> 
> -Charlie Q


Again I agree that misting that chilled water is best way to cool the air quickly, but for most it won't be practical to do that more then once/twice a day, and between cycles the tank will have plenty of time to heat back up.

So I think we need the Tom's phase in there also to shoulder the load between misting cycles. But ya I think using that chilled water to mist with is great for squeezing even more cooling potential from the system. So we could have a 3 or 4 phase system.

1. chilled water through toms, 2. chilled air through air pump, 3. chilled misting. Hell add phase 4. Chilled fogger on its own reservoir or modified to use the fridge's water reservoir, like with another tom's pump and an overflow made in the fogger's internal reservoir so excess goes back into the fridge reservoir (Ultrasonic "cool mist" fog comes out fairly chilled though, so might skip that effort).

So you're timing schedual might look like this... 
1. Tom chilled water/air runs all day/night
2. Lights on
3. 2 hrs later fog cycle runs (you choose duration)
4. Noon cooling mist comes on (duration chosen that doesn't flood tank)
4. 2 hours later fog comes one
5. 2 hours or so later evening cooling mist runs
6. Lights off at some point after last mist
7. run a fog cycle if you'd like periodically through the night....maybe 1 short mist cycle too?

And you if you have a fan setup on the viv that on a timer coming on at the hottest points of the day could take the edge off the heat too (But if you run the fans to often and/or at to high of speed then you might actually inhibit your cooling efforts?) 

Here is a line of plug and play adjustable rate fans for good price and a variety of sizes, and includes dual fan/speed control options...
http://www.amazon.com/gp/product/B009OY3EZG/ref=noref?ie=UTF8&psc=1&s=hi
Anyways something like that. 

As for frogs/animals and chilled mist water...

Unless the system puts the internal viv temps under 60f, or down to 50f and below, and does it very rapidly I don't think it would be an issue. Most darts can handle short durations in the 50f area, though I wouldn't wanna subject em to repeated periods of temps like that. But if our cooling system is that effective then chances are we can use timers to tune it so we get just the cooling we need. 

For me I'm looking at a system like this to keep Pseudotriton ruber, So temps under 70 and down into the 50's are what I want. And these can be kept mostly aquatic so as long as their water is cooled, I should be good to go.

I don't have to worry much about the ambient air as long as the water is ok. They can thermoregulate on their own and stick to hides on land during day if they want, or only come out onto land at night. (Because in my setup I would give them some land area just in case, others do keep them fully aquatic though)


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## Charlie Q

i think that your multi faceted approach would work well, and you could probably do some decent cooling. i'd sure like to see someone build on and report on how well it works.



Dendro Dave said:


> I'm not a math guy but I bet there is some equation that would give us ideal flow rate/to chilled water volume ratio or something.


there is. it sucks. and it is all dependent upon variables which would be very hard to define in a vivarium. it is much easier when you can calculate the surface area of some pipes and find the thermal conductivity of the material it is made out of. I would not be able to give you any reasonable numbers with all the unknowns of a vivarium.

there are 2 additional ways i have been thinking about which would operate much more like an air-conditioning unit (it gets too hot, and you can flip a switch to cool it down. or better yet, use a simple thermostat to control the on/off) they go like this:

1. when it gets too hot in the viv, air is drawn from the vivarium and into an A/C box. energy is extracted from the air in the form of vapor to liquid phase change, and condensation results. the air is now dry (as dry as possible at least). on its way back into the viv, cold water (from the mini fridge set up) is misted into the dry stream of air. energy moves from the air into the water droplets, and changes them into vapor, restoring humidity before the air hits the tank. all the condensation can be collected and added to the mini fridge reservoir. 

2. us the air in the viv as if it were the working fluid of a refrigeration cycle. suck air out of the viv and compress it. this will cause the temp to rise, bleed off the heat into your room with a fan, and expand it back into the viv. the expansion should then cool it considerably. just like the nozzle of a compressed air tank gets cold when you use it.


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## Dendro Dave

I'll just reply in the quote and I'm writing this so it will let me post, cuz since I replied in the quote I had to few msg characters for it to send the dang msg first try 



Charlie Q said:


> i think that your multi faceted approach would work well, and you could probably do some decent cooling. i'd sure like to see someone build on and report on how well it works.
> 
> 
> 
> there is. it sucks. and it is all dependent upon variables which would be very hard to define in a vivarium. it is much easier when you can calculate the surface area of some pipes and find the thermal conductivity of the material it is made out of. I would not be able to give you any reasonable numbers with all the unknowns of a vivarium.
> 
> there are 2 additional ways i have been thinking about which would operate much more like an air-conditioning unit (it gets too hot, and you can flip a switch to cool it down. or better yet, use a simple thermostat to control the on/off) they go like this:
> 
> 1. when it gets too hot in the viv, air is drawn from the vivarium and into an A/C box. energy is extracted from the air in the form of vapor to liquid phase change, and condensation results. the air is now dry (as dry as possible at least). on its way back into the viv, cold water (from the mini fridge set up) is misted into the dry stream of air. energy moves from the air into the water droplets, and changes them into vapor, restoring humidity before the air hits the tank. all the condensation can be collected and added to the mini fridge reservoir. Ya there are a lot of variable. If someone who knew what they were doing (not me ) were to apply it, it might help them get in the ballpark?
> 
> I like it... You might even be able to do it by just pumping air into "mist chamber" with foam panels where the intake and output hole are like this (http://www.dendroboard.com/forum/pa...c-filter-foam-fans-vents-ff-lids-etc-etc.html), and mist that air with chilled misting water, then suck/blow it out and into the viv. Again insulating pipes/lines should increase efficiency.
> 
> 
> 2. us the air in the viv as if it were the working fluid of a refrigeration cycle. suck air out of the viv and compress it. this will cause the temp to rise, bleed off the heat into your room with a fan, and expand it back into the viv. the expansion should then cool it considerably. just like the nozzle of a compressed air tank gets cold when you use it. Very intersting idea, not sure how practical it would be to implement. I can't think of an easy and relatively silent way to compress the air, but if someone could that might be a viable option. I'd love see what someone comes up with in the attempt


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## Charlie Q

I think it is pretty much useless to try to calculate the heat transfer rate of the air to water heat exchange. each vivarium would be different, and it would be a real headache. you could get a ballpark of your mist effect though. if you have a flow rate, and a mist rate, the latent heat of vaporization is 2270 kj/kg and the specific heat of water is 1.006 kj/kg*K 

so let's assume we have 100 kg of 80 degree F air flowing each hour and and 1 kg of water being misted in during that time. neglecting all other heat transfer besides the water evaporation, employing Q=mc(deltaT) we would have: 

(-2270 kj/kg)(1kg) = (1.006 kj/kg*K)(100 kg)(T - 26.666 C) 

leading to a final temperature of 4.10205 C or 40 F

that would be an ideal case. also that means that the humidity would be at 10g of water per kg of air. which is actually pretty reasonable from what i have read. the hardest part would be drying the air.


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## Dendro Dave

Charlie Q said:


> I think it is pretty much useless to try to calculate the heat transfer rate of the air to water heat exchange. each vivarium would be different, and it would be a real headache. you could get a ballpark of your mist effect though. if you have a flow rate, and a mist rate, the latent heat of vaporization is 2270 kj/kg and the specific heat of water is 1.006 kj/kg*K
> 
> so let's assume we have 100 kg of 80 degree F air flowing each hour and and 1 kg of water being misted in during that time. neglecting all other heat transfer besides the water evaporation, employing Q=mc(deltaT) we would have:
> 
> (-2270 kj/kg)(1kg) = (1.006 kj/kg*K)(100 kg)(T - 26.666 C)
> 
> leading to a final temperature of 4.10205 C or 40 F
> 
> that would be an ideal case. also that means that the humidity would be at 10g of water per kg of air. which is actually pretty reasonable from what i have read. the hardest part would be drying the air.


Interesting... they actually make small dehumidifiers for gun cabinets and stuff. I was going to use one in my desert viv but abandoned the build due to cash flow issues. I'll see if I can find a link to the product when I'm not on my phone


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## Charlie Q

ach. i realized i made a typo. the calcs are correct, but i meant to say that 1.006 is the specific heat of dry air. not of water.


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## Dendro Dave

Ok here is the dehumidifier...









Stack-On Wireless Rechargeable Silica Gel Desiccant Dehumidifier

(Lots on ebay, and many are rebranded under different brands like remington, stack on, eva dry etc..etc... I didn't shop for best price.

They plug in to recharge, so you could set it on a timer to recharge periodically and then let it do its thing when timer is off, because it doesn't need power (Yes you read that right) when it is dehumidifying. 

Another device...









Dehumidifiers & Desiccant | Gun Cases & Safes | Shooting Gear

And more...
Dehumidifiers & Desiccant | Gun Cases & Safes | Shooting Gear


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## Charlie Q

thats like the little packets that come in the beef jerky... it is handy that you can just throw them in when you need it, and recharge when you don't. but that might not be active enough to dehumidify the air as it is passing through. it will slowly absorb the moisture, but it might not work well enough, idk. i worry because i find that beef jerky packages are far too moist, and i end up drying them out further before i eat it. =)


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## Dendro Dave

Charlie Q said:


> thats like the little packets that come in the beef jerky... it is handy that you can just throw them in when you need it, and recharge when you don't. but that might not be active enough to dehumidify the air as it is passing through. it will slowly absorb the moisture, but it might not work well enough, idk. i worry because i find that beef jerky packages are far too moist, and i end up drying them out further before i eat it. =)


Hard to say, you could always put em in a cube config, use 6 at once 

Turns out that rod contraption I guess isn't a dehumidifier, but rather a low powered heater some reviewers said. It just raises the the temp a little so the dew point rises to prevent condensation inside the gun cabinet... I'm guessing that wouldn't help us much given we are trying to cool something?


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## Charlie Q

yeah, you need cool material for the water to condense on. you might be able to just run it through a little radiator heat exchange unit with a fan blowing through the fins. problem would be the condensation would collect on the inside and cause issues. 

it is an interesting issue, and more difficult than finding a solution is finding a cheap solution...


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## grabberorangestang

So I have changed my plans. I was excited to go with my first plan because I wanted cold drinks near my frogs  . I have decided to change plans, with the help of goof. He did a peltier cooling setup that didn't look very jerry-rigged. I'm thinking about using his plan as a starting point, possibly adding touches here and there. Here is another quick paint photo of the setup.


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## hypostatic

So there was a recent thread on DB on viv cooling, so I thought I'd archive it in this thread as well. The author's system keeps the temp in the 40s and 50s:
http://www.dendroboard.com/forum/pl...ted-growing-orchids-grow-cooler-climates.html

Also did a google search in DB of "peltier" and found some more threads about peltier coolers. I haven't checked them out yet, but they're worth listing for now at least:
http://www.dendroboard.com/forum/parts-construction/82510-thermoelectric-cooler-cool-viv.html
http://www.dendroboard.com/forum/parts-construction/20323-peltier-air-conditioning-project.html
http://www.dendroboard.com/forum/parts-construction/9045-peltier-cooler.html
http://www.dendroboard.com/forum/parts-construction/13882-peltier-air-conditioner-construction.html


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## PanicButton

Resurrection post.. I'm setting up a peltier to cool air in my tank soon here as well and I thought I'd mention something. In tanks that receive regular misting anyway, as long as your cool side heat sink was in the environment, even with condensation evaporative cooling will take place as well. Assuming your heat is environmental and not originating within the tank the results will be cumulative. Yes water is condensing before air is being cooled however assuming moisture is readily available within the substrate and surfaces, evaporative cooling will also take place because the air is going to stay saturated until it drops below the dew point. So heat is sapped from everywhere, granted it's not efficient, but what currently is? Once it "catches up" with itself, humidity and temp will both settle lower. But it'd require constant operation to not be working against itself... think of cruising vs acceleration in an engine, hugely different energy requirements. Correct me if I'm wrong, just my 2 cents. I'll report back with actual data. Vivs new location drives Temps over 80 all day, System is going to be on 2 thermostatic relays on a 2ch timer relay to control day/night Temps, going to set them for 75/65 and this is a heavily planted 65g Viv with lots of water, large surface area waterfall, active air circulation, 10 point 200psi misting system set to go off twelve hours apart. Using standard actively cooled aluminum heat sinks(maleable copper spray on mating surfaces is essential by the way in heat transfer applications where the surfaces aren't true on a microscopic level) at first, but i might play around with a/w, heat pipes, and pure copper if the peltier isn't losing heat fast enough. I have a FLIR infrared camera for my phone, I'll post some heat distribution pictures along the way. Worst case scenario, hard application specific data.


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## PanicButton

So I'm still waiting on my endothermic end for the peltier setup but in the meantime I have used a small aquarium chiller set up with a remote probe under my substrate, temp set to 68° F (highland plants and frogs). Water leaves the vivarium, goes through a hose to my misting water reservoir where it passes through copper tubing coiled inside, from there to the chiller, it's cooled, goes back into the reservoir through another copper coil, then back to the vivarium where it's deposited on top of a waterfall. This keeps water leaving the tank at 69, water going back in at 66. The misting reservoir temp sits at 73. This had resulted in an interesting temp gradient. Bottom few inches of the tank are in the lower 70s and it quickly raises to 81 towards the top. There's tons of active circulation and my humidity sits about 80-85%. I'm thinking with the addition of a peltier cooler running at might only, I should be able to achieve the lower nighttime temperature results I'm looking for. I'll post pics soon.


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## PanicButton

So 60w peltier cooler with active air cooled aluminum heat sinks, exothermic side >3x the size of the endothermic side, has been installed in the tank for about a week now. ~5°F drop at its peak performance. But the tank has an acrylic canopy on it that encases the led lights and exothermic side of the peltier and gets HOT. Mostly from the peltier. I was hoping to get air temps down to 65-75 consistently. So I've ordered another set of peltiers, tec1-12715 this time, off the top of my head good for 70°C temperature gradient.This time I'm using 2 of them, each set up as: aluminum active air cooled endothermic side>copper shim>peltier>copper cpu water block>pump with reservoir>piped outside>240mm radiator w/ 2x120mm high pressure fans. All powered by a 500w dc transformer. I've designed engine cooling systems and this is a cakewalk in comparison. Peltiers in peak conditions are 33.3% efficient, so allowing 20w max for arduino modules, relays, fans, and pump, that's going to be exhausting roughly 160w of energy out of the air. Right now, at very best I'm exhausting 20w and that gets me ~3-5°F temp drop depending on how much heat the leds are also making at the time. So far humidity is also still fine but misting is programmable and very nice fine high pressure spray, I can crank it if needed. I'll have it up in the next few days, cost me about $100 all said and done. If I remember to once i have it together, I'll set up my IR camera on time lapse for the first run


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## PanicButton

Okay. Just got the final pieces today and threw together a prototype. So it goes aluminum heatsink(chosen for the low points around the fan so to collect condensation) >solid aluminum stock that I polished the ends of>copper shim>tec1-12715 peltier heat exchanger>copper plate water block>×2>water pump with top loading reservoir(high point in the system)>240mm radiator with 2x 90cfm dc fans. It's all driven by a 500w dc transformer and runs through 2 different temp control relays which rejoin in a timer relay before going to the coolers so I can set different day/night Temps. The fans on the heatsinks pull air up and blow it out laterally to encourage good convection. Theres a high pressure misting system set to spray from 12 points every other hour for 30 seconds also on a day/night relay. Roughly half a gallon a day. Theres a waterfall with water cooled to 72°F by a remote chiller that runs through the misting reservior to cool that as well. Misting reservior is set with a float valve on a dedicated ro/di filter. Theres an auto top off system with controller being used to dump out past a certain water level. Water flows through hydropinic media used as a base layer before going into an internal filtration system behind the back wall that's about 5" thick. It started life as an acryllic ifs reef tank so its sealed except for where ive mounted intake and exhaust fans(fine mesh on tank side) but those only come on 30 seconds alternating hours with misting. The day and night temps have been set to 75° and 68°. Its been on an hour and I've dropped about 6°F so far. No doubt it'll continue to drop into its target range, the heatsinks are VERY cold, but tons of condensation, but I've placed them above plants that like constant water so it works out. So for future reference, if you do it right, peltier coolers have loads of potential. Feel free to ask for any tips if anyone wants to replicate this. I'll drop back by after a few days of operation to give my final rundown.


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## PanicButton

So I went to go snap a few pictures and found one of my endothermic heatsinks (opposite side of the waterfall) completely covered in ice haha system seems to be doing its job.


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## PanicButton

As promised here are also some preliminary infrared photos. Obvious which one is the before haha that's from when I had the single 60w air cooled peltier on it and the after was taken after about 90 mins of operation, so it still has a long way to go to catch up and settle in. I'll post more later, I just wish I'd documented the before more thoroughly.


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## PanicButton

Here's a thermal pic of the whole system working too.


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## PanicButton

So obviously I underestimated these things.. going to need to come up with a better cold side. Debating between a passive system that extends the length of the tank and joins the two heatsinks with a single piece or just two larger actively cooled heatsinks..


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## PanicButton

And tragedy strikes. Okay. Way too cold. Poor little guy froze  I'm going to need a larger heatsink for sure. I hadn't anticipated this happening, I really did not think they would be foolish enough to hang around the cold spots.


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## sentacursa

here's a solution...

Suncourt Ductstat Plug-In Thermostat Temperature Sensitive Switch-DS100 - The Home Depot

i run one like this, u can use it with heating or cooling
its a basic power supply with thermo options.. thing runs amazing


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## easttex

I have often pondered chilling a reservoir of water, possibly containing food safe glycol as an antifreeze, and circulating that through a forced air heat exchanger as a means of chilling a vivarium. You seem I have the components readily available; perhaps it might be work a try?

Sent from my SAMSUNG-SM-G900A using Tapatalk


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## PanicButton

I do already have thermostatic relays in place to monitor the temperature inside the vivarium so the whole thing doesn't get too cold and the system doesn't run all the time. Problem is that the heatsinks freeze before the tank hits target temp. I know I could just run another relay in series with the current ones with probes at the heatsinks but then I'll constantly be cycling on/off before reaching my target temp, if ever. Instead I'm going the simple route of using larger heatsink(s), I've made a simple one out of aluminum stock to span the length of the tank and I'm going to install it later today, that should keep it from freezing. As far as chilling water and circulating that through another water to air heat exchanger, I'd considered it as well but it wouldn't really change anything and id lose efficiency transferring the heat(or lack of) through another media as well as have a big ugly exchanger in the tank. There wouldn't be any gain from complicating the system to that point if I'm able to use solid state heatsinks inside the tank properly.


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## skanderson

when I built my large viv I thought I was going to have to actively cool it to keep in in the 70s. I use a lot of r/o water to keep my vivs watered and reef and fw tank topped off. my plan was to make a coil of copper pipe and run it inside of one of my 4inch air vents and then run the waste r/o water through the copper pipe. my tap water is in the 50s so I should be able to get significant cooling just using a waste product. if I ever get bored enough with my current projects I have considered making a largish vertical viv for cloud forest type plants. if I make it I will post here to show how it works, or doesn't.


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## PanicButton

Yea these are mostly all highland nepenthes(cloud forest) in this tank, that's how it started life before wanting a little more action in there. Decouple thoughts on that, I don't know about you but my r/o system does not come close to running all the time, had you considered that? The smallest units I've come across produce 24gpd which you'd have to have some serious water needs to be cranking out even that much. You may have, i don't know but that was the first thing that stopped me from trying that seeing as I already have the ro unit under the tank anyway. Not only that also consider how far you've got to run that water in the hp tubing, that stiffs pretty small and the flow is real slow. I would not be at all surprised if it was ambient temperature by the time it makes the waste drain.


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## PanicButton

In fact you'd do yourself a huge solid by using your tap inlet water before going to the ro system instead of your waste water if you are going to go that route anyway. Slightly more flow and lower temps


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## PanicButton

Also remember that 1 btu/hr is the amount of energy it takes to raise 1 pound of water by 1 degree over the course of an hour. So 1/8 gallon. So assuming that you're producing 1 gallon per hour at 50° and warming it to 70° AND its consitently flowing, you've got a cooling capacity of roughly 160 btu/hrs. Which is about 47 watt/hours. And thats if everything runs at 100% peak efficiency, which is impossible anyway. Unless you have a very tiny tank, this is not going to cause any significant impact. Not trying to be a downer but I was an hvac tech in the past so I'm just trying to pass on relevant info that I hope will help before you spend your money unnecessarily.


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## kromar

anyone tried some swamp or bong cooler (evaporative cooling)? might be interesting to see how something like that could be incorporated and how effektive it can be


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## PanicButton

Okay, that did the trick. I rigged up a test piece and it's preforming amazingly. I'll order a proper heatsink to replace it just so it looks nicer but I got the performance im.looking for. Overnights I was consistently around 65(my test low) and it switched over to 75 starting at 8am so it's slowly warming up already but just look at the thermal distribution. There are 2 small fans mounted blowing out across the heat sink.


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## surferseatsharks

I think Charlie Q's design has the greatest chance of working, complex systems rarely work longterm as you are battling high humidity in a small chamber all the while trying to avoid extreme swings in temp/humidity. I live in AZ and swamp coolers (basically his design) work extremely well with little upkeep.


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## PanicButton

I'm not seeing a whole lot of potential for swamp cooling either. That method relys on the airs capacity for moisture to be low enough that it can evaporate substantial sounds of water. In our vivs the air is often at its saturation point. If you wanted to give it a go anyway, I'd try using the air outside the viv and blowing through a cooler into the tank. Otherwise you'll just be circulating air through a wet Sponge.


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## PanicButton

surferseatsharks said:


> I think Charlie Q's design has the greatest chance of working, complex systems rarely work longterm as you are battling high humidity in a small chamber all the while trying to avoid extreme swings in temp/humidity. I live in AZ and swamp coolers (basically his design) work extremely well with little upkeep.


Well anywhere that doesn't struggle to keep humidity up won't see this. Here in the Midwest where our air is already very high in humidity, that just won't work. This system works very well, granted it is wasteful in that it's constantly battling phases changes of water but no matter what you cool a high humidity environment with you will ALWAYS get condensation so the systems capacity for cooling must be high enough to work regardless. As far as it being too complex to last, I do not follow, the only moving part is a water pump and the only parts exposes to moisture are aluminum. And as I've shown, I'm getting 20°F drops and could likely go further if I set my tstats lower.


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## PanicButton

And granted, I spent a few hundred on prototyping, but anyone who should want to mimic this system should be able to get away with under $120 or so. I'm happy to help calculate thermal loads and energy requirements for anyone interested and while only to protect potential commercial interests as I do currently work in the feild, my boss is helping me to patent this design  tank used to sit at 84-90, 85% humidity. Ambient room temp is about 78-82. And now the tank sits 65-74, still 85% humidity. I couldn't be happier with this success.


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## MartinK

Hello guys,

I found very interesting hints and ideas in this forum and thank you for that! I decided to share my own setup that hopefully will help and inspire others. My requirements were following:

1) keep vivarium cool (up to 20'C - 68'F) and humid
2) simple and maintenance free setup

So I connected the TECO TK-150 aqua chiller, an old empty aqua filter and a PC-case water radiator by hoses and placed 2 fans on the radiator. The aqua chiller cools the water to 12'C with hysteresis of 4'C, so it kicks in when the water has 16'C and turns off when 12'C (the image had different settings). The aqua filter pumps the water in the circuit and serves as a reservoir of 2 litres. This way, the radiator on the top of the vivarium is always cold. Also, the chiller kicks in once in an hour, which is acceptable. The hysteresis or the reservoir can be larger for longer intervals. So, the water temperature is controlled by the chiller. The vivarium has 2 temperature and 1 humidity sensors connected to Arduino that controls 2 fans placed on the radiator. So, the temperature inside of the viv is controlled by the Arduino by adjusting rotation of the PWM fans. I have this setup for 8 months now and the results are excellent:

1) the viv can be cooler by 10'C (18'F) than surroundings. In summer, room temperature was slightly over 30'C and viv roughly 21'C. The chiller was running almost constantly (150W consumption). Once the temperature hits 20'C, the fans immediately turn on. They also do on a time interval. Usually, the temp is kept at 16-17'C (60'F) in a normal room temperature 22'C (72'F).

2) aircons dry out air, but not in this case. Air is sucked up from the room, which has a normal relative humidity (40 - 70%). As it passes the radiator, cools down and its relative humidity increases. So in the viv, the humidity is always 96 - 100%, which makes it very humid actually. It's OK for me. During wet season I can see little "raining" to the viv from the radiator as the air condensates.

3) my previous setup was semi-aquatic and the aqua chiller cooled directly the water in the viv to 16'C. The problem was that the water was cold and the air was hot.

4) I use RO water that keeps the tubes algae-free and should not corrode the radiator much. The radiator is copper-made, so the water is toxic and must be enclosed in the system.

To conclude, the system is reliable and works very well. Once in 2 months, I have to release some air from the tubes. The Arduino controls many other things, but it is not necessary to use it. The fans may be controlled directly by a temp probe or even left uncontrolled in a constant slow mode. A drawback can be efficiency since the air circulation is open. I don't know to calculate it, but usually the chiller is running 30 minutes and 30 minutes is shut off. A closed circulation would be more complicated and would dry the air. In future, I'd like to create a much bigger setup, hopefully being able to create the artificial snow inside. This is really challenging and energy-demanding, however, doable :-D


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