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New Highland cooling system using slightly modified A/C

Hey everyone,

Here is my new idea for cooling my highland terrarium.

Essentially I've just taken a 6000 btu a/c (I got for free off kijiji), opened it up, removed the evaporation fan, moved the temp sensor off the rad. Then I bent out the front cooling radiator so that I can insert it into my terrarium. I didnt modify the wiring or anything else on the a/c so it's not that hard to do if you're interested in a nice cooling system. I ran the a/c for 10 minutes with no insulation, just open in my room (23 celcius); I got temps of 5 celcius off the rad, and the whole rad was frosted. I'm gonna hook the a/c up to my hygrotherm temperature control device so that it can turn it off and on when needed. Here's some pics:

Here is the front cooling rad from the a/c I pulled out of the box.


Here is the a/c after I put it back together.


Last thing to do is insulate a section of my tank, and then drop the rad in. I'm gonna place some cpu fans on the rad as well to stop it from frosting. Also I need to insulate the copper piping that runs from the compressor to the cooling rad. I'll post some more pics soon. I get a couple of the frosted over rad, it looks really cool (no pun intended) :)

I'm gonna move all my plants out of my tank and into another temporary one so that I can run some tests. I'll post all my info here.

I chose an a/c because they are made to be run for long periods of time, unlike fridges which run off and on. So I shouldnt have any problem with burning out the compressor.

If anyone else is interested in doing a setup like this, I can provide you with step by step instructions and and some more pics.

Here are some more pics I just took.

A/C Running for 2 minutes - you can see the frost beginning to build up and the temp went from 23 celcius to 7.





Here's is the a/c after running for about 6 minutes or so - more frost, and cooler temps :).





And here is a rough design I drew up in mspaint. pink is insulation.



Here's some pics of the tube after I put the insulation on. Tests are pending me getting my tank insulated at the moment.



Update:

I'm currently rewiring my a/c so that the compressor and fan come on when i plug the unit in. Currently the unit goes to a standby mode when power reaches it, which is not what i want; i need the unit to come on when it gets power. All I'm doing is inserting a toggle switch between the fan/compressor and the power outlet and bypassing the whole digital control unit.

Essentially I'd suggest that if you want to do this modification it would be best to use an a/c that uses knobs and turns on automatically when power reaches the unit so that you do not have to rewire the thing like i have to. If you use a digital one, make sure it has an auto start feature.

I'll update once I finish up the wiring.

Update:

I've completed the rewiring. It was fairly easy and straight forward.

I just had to take the low fan speed wire and the compressor power wire, join them and then attach them to one end of my switch. Then I took the power wire and hooked it to the other end. Now the A/C turns on and off with the flick of a switch and I was able to bypass the whole standby feature. I'll post some pics tonight.

I plugged it into my hygrotherm temp and humidity control unit and it works great :). I then ran the A/C for about 5 minutes and the whole rad was covered in frost. Temps on the rad were about 5 degrees celcius. I then placed a fan behind the rad and the temps dropped down to -8 in about 2 minutes. Now I just need to finish insulating the tank and I'll be able to run some tests. Looks promising :).

I'm on the fence on how to setup my fan system for the rad though. Anyone have any ideas? I was thinking I would either place the fans directly on the rad but the temps get quite cold, or box the rad in with insulation and then have one fan blow air out and one blowing into the box (like i showed in my crappy mspaint diagram).
 
Wow. This is quite an impressive cooling system. Just another testament to the great lengths that we Humans will go to grow crazy things where we aren't supposed to.

I hope to see some beautiful Ultrahighlanders growing in there!

It makes me glad that I live in Alaska, and do not need such a complicated cooling system as this.
 
Wow. This is quite an impressive cooling system. Just another testament to the great lengths that we Humans will go to grow crazy things where we aren't supposed to.

I hope to see some beautiful Ultrahighlanders growing in there!

It makes me glad that I live in Alaska, and do not need such a complicated cooling system as this.

ya it's pretty extreme lol, but it must be done for the greater good of the Nepenthes growing community lol. :D

I live in Canada so I'll only have to use this during the summer, as during the winter i just put a fan in front of a window and blow the cold air off it to my tank.

I currently dont have any ultrahighlands, but soon will now that I have this baby :) N. villosa here i come!
 
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Good stuff, rob! I am currently working on doing a fairly clean looking set up for my highlands vivarium. I am building a unit that houses fans and a peltier (thermoelectric) cooler rigged up to a thermostat. I should be getting it sometime this week or early next week, and I plan to post on how I am putting it all together.
 
Good stuff, rob! I am currently working on doing a fairly clean looking set up for my highlands vivarium. I am building a unit that houses fans and a peltier (thermoelectric) cooler rigged up to a thermostat. I should be getting it sometime this week or early next week, and I plan to post on how I am putting it all together.

Thanks Soopaman :).

Your idea with the peltier is great, I was thinking of doing that too but then opted for the a/c cause I couldnt get a peltier chip anywhere near where I live. If I was to get one I would have to order it. Plus the a/c was cheaper since it was free lol, so I improvised :).

I'll be mounting a fan onto my rad tonight and doing some tests. I'll post any results I get.
 
Thanks Soopaman :).

Your idea with the peltier is great, I was thinking of doing that too but then opted for the a/c cause I couldnt get a peltier chip anywhere near where I live. If I was to get one I would have to order it. Plus the a/c was cheaper since it was free lol, so I improvised :).

I'll be mounting a fan onto my rad tonight and doing some tests. I'll post any results I get.


I ordered mine off of ebay from a fellow in Canada. He sends them already put together with a fan and a heat sink, so it's pretty much ready to go except it needs to be hooked up to a 3Amp power supply, which he doesn't send. It was a pretty good deal too, getting two of them for $22 plus shipping.
 
I ordered mine off of ebay from a fellow in Canada. He sends them already put together with a fan and a heat sink, so it's pretty much ready to go except it needs to be hooked up to a 3Amp power supply, which he doesn't send. It was a pretty good deal too, getting two of them for $22 plus shipping.

Good deal dude. Looking forward to you post about it :) How big is the tank you're cooling?

I'm going to be putting my ac into a 4 footer.
 
It's a fairly small chamber, 18" by 18" by 24". It's the vivarium shown in this thread:
http://www.terraforums.com/forums/showthread.php?t=125388

Very nice dude :). I have an exo terra exactly the same. I house my lowlanders in it. Here's a link to a tour of my setup.

http://ontariocarnivorousplants.forumup.com/viewtopic.php?t=76&mforum=ontariocarnivorousplants

Where in the terrarium are you going to put the peltiers? at the top?

I have a plastic cover which protected the evap fan from hitting the rad. I'm thinking of mounting it back on and putting a high CFM computer fan on it. see the pics below.




I'm thinking of using either 2 of these:
http://www.sohodiffusion.com/prod/16138/SCYTHE-ULTRA-KAZE-120MM-HIGH-STATIC-PRESSURE-FAN-3.html

or one of these:
http://www.sohodiffusion.com/prod/15319/ANTEC-TRICOOL-BIG-BOY-200-CASE-FAN.html

What do you think is betteR? 1 big one? or two small ones? the smaller ones have the same CFM as the big one, so im thinking 2 smaller ones are better than 1 big one.
 
  • #10
I say get the two smalls fans instead of one big one, honestly.

I'm going to be using just one peltier cooler which will go at the top of the terrarium. Basically there will be a sort of cover that goes over the top of the terrarium, and inside will be the peltier cooler. I am going to have two fans at the back pulling out the hot air produced by the lights. The peltier will have a fan directly under it which will pull the colder air into the tank. The peltier unit itself is controlled by timed thermostat to keep it 70-75 in the day, and 50 at night.

Here's a pic of the new top I put on the tank. Basically I took a sheet of clear acrylic and cut it to fit inside the original Exo-terra top, and cut a hole in the middle. I used silicon to adhere it to the top:

lid.jpg


Your set up looks good, by the way. What kind of lights are you using over your lowland tank?
 
  • #11
I say get the two smalls fans instead of one big one, honestly.

I'm going to be using just one peltier cooler which will go at the top of the terrarium. Basically there will be a sort of cover that goes over the top of the terrarium, and inside will be the peltier cooler. I am going to have two fans at the back pulling out the hot air produced by the lights. The peltier will have a fan directly under it which will pull the colder air into the tank. The peltier unit itself is controlled by timed thermostat to keep it 70-75 in the day, and 50 at night.

Here's a pic of the new top I put on the tank. Basically I took a sheet of clear acrylic and cut it to fit inside the original Exo-terra top, and cut a hole in the middle. I used silicon to adhere it to the top:

lid.jpg


Your set up looks good, by the way. What kind of lights are you using over your lowland tank?

Nice job with the acrylic, I'm gonna run out to the homedepot and get me some too now lol. Currently i have a piece of glass above mine but it's a little to thick for my liking.

I use t5 54watt HOs for both my lowland and highland tanks. I have 32 watt T8s over my drosera.
 
  • #12
Update:

When the AC turns on the RH was dropping to 30-40% before my humidifier could turn on and compensate, which alarmed me. So I decided to try and reduce the exposure of the coils to the humid air in the tank.

First i took a regular bag and completely sealed the rad, took the fan off and placed it outside the bag, blowing on it. Didnt really do much in terms of lowering the temps, but the humidity didnt change. So I then decided to take a plastic box and seal the rad with the fan inside the box as well. I sealed the top of the box but left the bottom open. I then tested this and it still didnt cool much. So I then cut a small hole behind the fan so that some air would be pulled through. Now the RH drops to about 55%-60% and then the fogger comes on and quickly raises the RH back to 75%. Once the AC turns off the coils are kinda wet and the fan blowing over them also raises the humidity. I just checked the tank and it's at 88% RH.

The AC turns on when the temps hit 24c and then turns off when it gets to 23c. The coils are still cold so it still reduces the temps down to 22c and then starts to rise, so the AC doesnt actually run all that often. I set the night temp to 12c, so it shouldnt go below 10c i figure. I'll be testing the night temps tonight.

I put the villosa about 2inches from the rad, so it should be getting some really nice cold temps. My singalana is beside it too. Warmer highlanders are on the other side of the tank.

Do you guys think that the 2-5 minutes drop in RH to 55-60% will upset my plants? I think it's short enough not to bother them much. Any input would be awesome Smile.

I'd post some pics but my GF went on a road trip and took the camera, so I'll post some next weekend when I get it back.
 
  • #13
First of all - Rob, great looking setup! I'm growing some lowlanders & intermediates in a partially-sealed grow rack right now. I get temps between 70 and 80 and humidity between 50% and 85% or so. To branch into highlanders I will need some sort of cooling system. I'm thinking to do that, I would need a tank... my rack just isn't well-sealed enough.

@soopaman - would you mind PMing me a link to that eBay listing? I did a quick search but couldn't find anything that matched the price and description. I would be very interested in trying that out!
 
  • #14
First of all - Rob, great looking setup! I'm growing some lowlanders & intermediates in a partially-sealed grow rack right now. I get temps between 70 and 80 and humidity between 50% and 85% or so. To branch into highlanders I will need some sort of cooling system. I'm thinking to do that, I would need a tank... my rack just isn't well-sealed enough.

@soopaman - would you mind PMing me a link to that eBay listing? I did a quick search but couldn't find anything that matched the price and description. I would be very interested in trying that out!

It would probably work with your grow rack as long as it is enclosed. The AC would just have to run longer and more often to compensate for the lack of insulation. I put a 4 inch thick board of insulation under my HL tank and am thinking I might box the section of the tank where the rad is with some more insulation.

If you want to do an AC setup like mine and have any questions just PM me.
 
  • #15
I would LOVE to do that setup... unfortunately due to crappy wiring in my apartment, my lease limits me to ONE A/C unit of 6,000 BTU max... and I choose to cool myself rather than my plants :) That's why I'm trying to get creative with cooling... and Peltier devices look like they fit the bill. That's a great setup you have, though. Very jealous.
 
  • #16
I would LOVE to do that setup... unfortunately due to crappy wiring in my apartment, my lease limits me to ONE A/C unit of 6,000 BTU max... and I choose to cool myself rather than my plants :) That's why I'm trying to get creative with cooling... and Peltier devices look like they fit the bill. That's a great setup you have, though. Very jealous.

Thats too bad, but you can still use some of the power of your AC to cool your plants. You can hook up a tube onto a small section of the vent from the AC unit and have it run right into your tank. Just make sure to intersect the tube with a humidifier before it gets into your tank.

Thanks for the kudos on my setup :).
 
  • #17
I honestly like Rob's set up a lot more than what I am doing, or trying to do. But alas, I too am not able to make use of an air conditioning unit to cool with.

I have had some trouble with the peltier, and I think I have determined the main problems, though I have some work around solutions until I can get things set straight.

First off, out of the box, the cooling stuff I bought on e-bay was not good enough. It was cheap, but the heatsink did not do a good enough job sucking heat away from the peltier end, and I could not get it cold enough.
So basically, I re-built it from the ground up with a really snazzy heatsink that is able to keep the hot side at less than or equal to the ambient temperature, so now the cold side is good. Unfortunately, I do not have a large enough "cold sink" on the cold side, at least not a large enough flat surface area. I believe what I need is a 1/8 thick copper plate, about 10"x10" with a fan blowing on it to circulate air. This is a possible next step for me. The other idea with my set up is to cool the water itself that runs through the tank. This water actually keeps the sides of the tank wet at all times, and if kept cooled, can bring the air temperature down significantly. What I have been doing to keep my plants doing well is cooling this water by basically changing it out with water I have had in the freezer for 2-3 hours before bedtime. Not quite frozen but getting there.

So my next steps forward are going to be either to install a circulation system so that the water is cooled by one or two peltiers, or by trying to increase the surface area on the cold sink with a large copper plate.

As far as humidity goes, the tank itself is pretty much sealed, and I can turn on a fogger that is in the water pool at the bottom and it will raise the humidity really quick.
 
  • #18
I honestly like Rob's set up a lot more than what I am doing, or trying to do. But alas, I too am not able to make use of an air conditioning unit to cool with.

I have had some trouble with the peltier, and I think I have determined the main problems, though I have some work around solutions until I can get things set straight.

First off, out of the box, the cooling stuff I bought on e-bay was not good enough. It was cheap, but the heatsink did not do a good enough job sucking heat away from the peltier end, and I could not get it cold enough.
So basically, I re-built it from the ground up with a really snazzy heatsink that is able to keep the hot side at less than or equal to the ambient temperature, so now the cold side is good. Unfortunately, I do not have a large enough "cold sink" on the cold side, at least not a large enough flat surface area. I believe what I need is a 1/8 thick copper plate, about 10"x10" with a fan blowing on it to circulate air. This is a possible next step for me. The other idea with my set up is to cool the water itself that runs through the tank. This water actually keeps the sides of the tank wet at all times, and if kept cooled, can bring the air temperature down significantly. What I have been doing to keep my plants doing well is cooling this water by basically changing it out with water I have had in the freezer for 2-3 hours before bedtime. Not quite frozen but getting there.

So my next steps forward are going to be either to install a circulation system so that the water is cooled by one or two peltiers, or by trying to increase the surface area on the cold sink with a large copper plate.

As far as humidity goes, the tank itself is pretty much sealed, and I can turn on a fogger that is in the water pool at the bottom and it will raise the humidity really quick.

Maybe try a water cooling system for a computer processor? They come with a pump, rad, tubes and fixtures. You could hook it all up inside the tank and have the peltier cool a small cooler that holds the water or coolant and then circulates the fluid through the rad, cooling the tank. cooling the water that runs down the sides of the tank is also a great idea. MAybe incorporate both mine and your ideas, making some sort of frankenstein contraption :D.
 
  • #19
Maybe try a water cooling system for a computer processor? They come with a pump, rad, tubes and fixtures. You could hook it all up inside the tank and have the peltier cool a small cooler that holds the water or coolant and then circulates the fluid through the rad, cooling the tank. cooling the water that runs down the sides of the tank is also a great idea. MAybe incorporate both mine and your ideas, making some sort of frankenstein contraption :D.

Haha, reading your post almost gave me a headache. I re-read it and understand what you mean now, but if I'm going to go that route, I might as well get an aquarium chiller and drop my $250 now and be done with it.

We'll see. How is your villosa doing? Luckily, I don't have mine to kill yet!
 
  • #20
Haha, reading your post almost gave me a headache. I re-read it and understand what you mean now, but if I'm going to go that route, I might as well get an aquarium chiller and drop my $250 now and be done with it.

We'll see. How is your villosa doing? Luckily, I don't have mine to kill yet!

The aquarium chiller will use as around as much power as a 6k btu AC, plus it needs to run constantly to keep the water in the reservoir cool. It would be cheaper to convert the AC, but it would take up more room in your setup. I'd go with the chiller if I had the cash available.

The villosa is adjusting. I've only had it for about a week or so. It's putting out a new leaf. Looks healthy :). I'm keeping it dryer than my other neps, and keeping my fingers crossed.
 
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