Cooling a terrarium

[schmiggle]

Are there any good, cheap ways to do this? I've read peltier systems are often ineffective, and I've used frozen water bottles, but they have all sorts of other problems (wet/leaky, hard to control temps, don't usually cool more than 10 degrees F). A/C and refrigeration are options, but super expensive. Are there things I'm not thinking of that I could use?

 

[viper69]

Yes there is, people use computer fans all the time for air circulation to maintain temps.

 

[The Snark]

Interesting problem. Fans don't cool ambient air, only the surfaces the wind blows on and the effectiveness is in direct relationship to the relative humidity.

Peltier coolers are an option but an expensive one. If you are trying to cool the air space in an enclosure you will need to use a fan and attach the cooler to a heat sink. Peltier systems also require some method of removing condensate on it's surface.

The tried and true method, blowing air through a porous dampened material is a fantastic way to cool and grow molds, mildew and fungi.

I'd say the most economical way is to buy an evaporative room cooler and duct the cold air over a condensing material to remove excess moisture then into the enclosure.

 

[MWAInverts]

What's causing your overheat is a bigger problem imo. Is it your ambient? Your lights? Lack of vents? Etc.

 

[Belegnole]

Easiest way to control enclosure temps is by controlling your room temp first. If that is fine I would ask if this "terrarium" is placed to get direct sunlight? If that is the case you are going to have to compare the requirements of the plants to any animal that you want to place in there. If humidity isn't an issue then venting the heat with fans could work. Otherwise you need a chiller.

In very hot climates I have seen specimens kept in what in essence would be a glass front refrigerator, with I assume a very accurate thermostat. In that vein I know that I have seen all sorts of smaller "fridges" with glass doors to hold soda etc.

But like MWAInverts, I would ask why is it hot to begin with.

 

[schmiggle]

I actually don't yet have a terrarium with the problem, I was merely hoping to plan ahead to avoid it in the first place. Since I have only had to worry about heating, I have no experience with cooling, which seems to be much more involved. I suppose I should have made that clear from the outset.

I don't really want to put in any animals, just a pitcher plant. I hope a refrigerator would be a last resort. :/ Room temps are fine now, I'm concerned about the summer. Last summer it got very hot (80+) but that was before insulation was installed, I'm guessing it won't get above mid-70's at night. But I'd like to cool to the low 60's, which is why I was asking. I'll use LED or fluorescent lighting, ideally the former, so that shouldn't cause a problem.

The suggestion with a fan is for evaporative cooling, right? Which is why Snark suggested blowing through a wet towel (essentially). If I have enough liquid, fans should increase humidity, I thought, because they would be putting more water into the air. I was thinking of trying a non-degradable cloth, like polyester, but perhaps your implication, Snark, was that it would cause mold in the terrarium.

A glass fridge seems like a good idea, but like I said, I'd like to avoid it unless absolutely necessary. But if cooling becomes enough of a problem, I'm not ideologically opposed.

 

[MWAInverts]

Are you growing a highland nepenthes? I currently have two N. rajah doing very well in a 80F+ room because I designed a miniature evaporative cooler that keeps the sterilite container at 68F days and 55F nights. Downside is I have to refill it daily. It evaporates a ton of water lol.

 

[schmiggle]

Wow, that sounds awesome! Yes, I was thinking of highland nepenthes, or possibly heliamphora...I'm impressed that you can grow N. Rajah in an 80+ room! Could you post more details about your setup?

 

[MWAInverts]

Yeah it's an all passive system. No motors etc. What I did was cut a 120mm square on one side and attached a 120mm PC fan to the outside. Then I bought a $5 humidifier pad from walmart and cut it to size so that it reaches all the way down the inside of the container and roughly 150mm wide to cover the hole entirely. I secured the pad with some wiring and filled the container with water so the pad acts as a wick constantly supplying moisture to be evaporated by the fan. Install a raised platform about 2" high for your plants to sit on and cover the top with a piece of glass, leaving 1/2" gap on one side for cool air to escape and you're done! If you connect the fan to an outside dry air source, you can achieve temps down to 45F nights. When I get a N. villosa again, I'll be doing just that.

 

[schmiggle]

I'm drooling enough to fill a moderately sized bathtub. That is absolutely phenomenal! Cheap, simple, not super hard to make, not energetically expensive...what more could a person want? Could you post pictures?

Also, do you have a way to control what temp you set it to? (e.g., it has the capacity to cool to 45, but you only want to cool to 55)

 

[MWAInverts]

Yeah I can post some pictures for you soon. As for a thermostat, I have a pretty big one that you can select between heat or cool, it'll shut off the heating or cooling depending on the mode selected. I'll have to go find it to get you the model but it's high quality. When my collection get bigger then I'll install it.