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A little while back on another post I had been writing about cooling a Viv with fans on a controller. The relay shown converts an inexpensive heating controller to work as a cooling controller that you can plug your fans into or other cooling device. ****USE AT YOUR OWN RISK***** if any of you blow your self, frogs, or homes up I take no responsibility.


Bob
 

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Any chance for a picture repost?
Or if anyone else has an idea for a fan thermostat that wont cost an arm and a leg, I'm all ears...
 

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I'd be all ears on that. I'm in the process of making one for my tank. I had recently bought a cool thermocontroller from http://www.dartfrog.co.uk. and am about to hook it up to a peltier cell pinned between 2 heatsinks...seems like peltiers need to be used in conjunction w heatsinks all the time. I had successfully destroyed one through testing w/o heatsinks.

I'd love to see what the others have done. I'm not sure if my solution will be good enough still after spending so much already.

Bing
 

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Don't forget to use thermal paste between the peltier and the heatsink. That's a very important part of making sure the heatsinks can do their job.
 

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I am also pretty interested to see what people have done. I would also like to know if anyone has used any kind of humidistat controllers too with their fans. I know that none of the computer fans and controllers monitor and humidity levels. It would be nice to have it hooked up to a misting system then you would never have to worry about it. I have done some research but everything I have found looks expensive and pretty complicated to use. here are some links

http://www.coylab.com/humidity_controller.html

http://www.thermalogic.com/pages/humisense.html

http://www.greenair.com/humidistat.htm

The third one looks like the ticket.
 

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That product from green air seems to be the ticket alright...but don't you think you can just turn on the fan against a pool of water, a waterfall or any water feature to get the air humid? Since the darts enjoy a close to 100% humidity, we have no worry about getting the air "too humid".

I checked the amperage rating of the humidity controller and it's 15 AMPS. A peltier also consumes power like a mad man...my peltier consumes 15 AMPS of power. An air conditioning unit is 30 AMPS. So w the two combined, might as well get an air conditioner for the room and have me enjoy the cooling effects as well! :roll:

Does my logic make sense?

Thanks,

Bing
 

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haa yeah I guess it is pretty much overkill. most breaker in a house are 15 amp unless they are for kitchen applaiances etc. So in order to operate you would need to put it on a 30amp breaker.
 

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A peltier consumes 15 amps at 12 VDC. That's only 180 watts. Your air conditioner consumes 15 amps as 120 VAC, that's 1800 watts. That's the difference.

With that humidity controller, you'd be switching the powersupply that runs the peltier. The powersupply will run at 120 VAC and will consume some power for itself in addition to the power needed for the peltier. Say we assume assume the powersupply it self uses the same amount of power as the peltier, add that to the power of the peltier and the total current draw on the from the humidity controller is only 3 amps - well within the switching capacity of the humidity controller.
 

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So what about a simple cooling thermostat to drive a fan?
IMO that would work fine. However, I think the more easily available are heating thermostats and for our needs ones with a remote temp sensor. There are several cheap "bang-bang" types for under $20. A "gutted" aquarium heater, the type with a remote sensor would work too. These type thermostats would need an additional DIY relay. Something with a 120VAC coil and double throw contacts. A cooling fan would have to use the normally closed contacts such that the contacts would open when the relay was energized by the thermostat output.

With this type setup, the relay could switch different voltage fans, as long as there was a supply for it. 120vac fans would be the easiest.

These thermostats have some amount of hysteresis around the setpoint. How much? Don't know. Couple degress probably. It might take some experimenting to get it setup correctly.

Now if someone was really clever they would design the relay box to use a standard relay socket, and have standard electrical plugs and outlets. Swap a timer in for the thermostat, and change the relay to an "interval on" TDR and you'd have a programmable controller for a misting system. TDR aren't cheap though, around $40.

YMMV,
EricG.NH
 

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This is the temprature controller I use to opperate the cooling fans in my reef's lighting system (http://ourworld.compuserve.com/homepage ... #therm.gif, see Electronic Thermostat and Relay Circuit). It can be configured for cooling or heating control and maintains the temprature within 3 degrees of the set point. It was pretty simple to build and has worked well for me for a couple of years now.

On my viv the fan is controlled by a timer. No problems there either.

Jay
 

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Sorry to hijack the thread but I think it is a relevant question,

By how much can a fan really drop the temperature in a viv? Meaning, if the ambient temperature is warm, let's say 90 degrees, and the insides of a viv is like 95, can adding a fan really drop the temperature to below 90? Reason I asked is that, adding all of the thermocontrollers and all the bells and whistles is fine, but without a "freon" on the fan, how effective is it?
 

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bluetip said:
Sorry to hijack the thread but I think it is a relevant question,

By how much can a fan really drop the temperature in a viv? Meaning, if the ambient temperature is warm, let's say 90 degrees, and the insides of a viv is like 95, can adding a fan really drop the temperature to below 90? Reason I asked is that, adding all of the thermocontrollers and all the bells and whistles is fine, but without a "freon" on the fan, how effective is it?
I think it depends on the lighting used and the ambient temperature of the room. All the fan really does is evacuate or mix the hot air created by the lighting. If the room temperature is too high, a fan will do very little to help.
 

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Evaporative cooling would be how the fan could bring a surface of the tank below the tank's temp, but I don't know if it could bring the whole tank's temp down or not - you'd have to try it and see.
 

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Evaporative cooling would be how the fan could bring a surface of the tank below the tank's temp, but I don't know if it could bring the whole tank's temp down or not - you'd have to try it and see.
Hmm...am I correct in thinking that evaporative cooling won't do the trick because humidity inside the viv is close to 100%, I don't think there's a lot of evaporation that will be happening...

the easiest way i think is to use a room a/c to cool the ambient temp.

for the more experimental maybe:

1.) use chilled misting water with fans inside the viv
2.) have a peltier contraption, with a fan, directed on to a constantly wet surface either a drip wall or a water feature.

These two suggestion I think can do the cooling while at the same time making sure that the humidity is up.

Makes sense?

Bing
 

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Good observation. I'm just tossing out some ideas here... If the air outside the tank were below 100% RH, and the fan were to suck air from the viv (this would provide a drop in the viv's RH and allow for evaporation) and push it into the room, then evaporative cooling would take place, but it almost certianly wouldn't be enough.
 

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If the air outside the tank were below 100% RH, and the fan were to suck air from the viv (this would provide a drop in the viv's RH and allow for evaporation) and push it into the room,
I think the tough part about this method is that, we'll have more trouble w the humidity now...if we keep in sucking air out of the viv, then we'll need a constant supply of mist or fog. If it's mist, we'll have an issue of continuous water supply. If it's fog...well, I've tried one of those foggers for tanks and they can pretty much heat up after running for awhile..soon enough, we'll have boiling water and hot fog...which brings us back to rising temperatures...


To my mind, maybe the best thing to do is to employ several techniques used in conjunction...

1- have double glass sides for your tank - it will keep the tank cooler longer.
2- have something similar to what Marty did w his rack in using the bernoulli effect (there's a picture of the effect from a thread by solly just created recently. the full rack construction is here: http://www.vivariumforum.com/?q=Dart-Fr ... uction-Log)
but instead of having fans pull hot air from top (where the lights are) to bottom , try and reverse the effect by having air move from bottom to top.
3- i suppose we really need to have an active device that will really get to cool the air and/or water in general (i.e. peltier)
4- ensure good ventilation between the lighting hood and the top of the tank.

That's everything I know and honestly, I'm still not so sure if that will successfully bring down the temps enough to make a real dent.


Thanks,

Bing
 
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