New Highland cooling system using slightly modified A/C

[robthered]

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).

[weeps]

I guess the main challenging here is frost and defrost issue on the coil.
You may not get smooth air flow for constant temperature control.

[robthered]

Originally Posted by weeps

I guess the main challenging here is frost and defrost issue on the coil.
You may not get smooth air flow for constant temperature control.

We'll see how it goes. I have 2 120mm Computer Case fans that run at 133 CFM with high static pressure (they're made to push/pull air through radiators for computer cooling) that I'm hooking up to the back of the rad with a shroud around it to maximize the airflow. I think it'll work out well. I'll post updates once I get the fans, should be in the next few days.

[caseyhoo]

For me, that is a big project. Looking forward for result of it.

Personnally, using aircond to cool down my plant environment is NO NO for me. Electric bill and HOME MINISTER will killing me... oooppppsss... I means Electric bill only...

[weeps]

Yeap, maybe using chiller is lower running cost.

[robthered]

Originally Posted by weeps

Yeap, maybe using chiller is lower running cost.

I thought of that and Chillers tend to use pretty much the same amount of watts as a 5000BTU AC. 1/4 HP chiller runs from about 200 - 500 watts depending on the load, anything more than 1/4 HP and the watts increase.

The max amount of watts my AC can pull is 500. So it's about equal, as the AC doesnt run constantly. Plus getting a used AC for 20 bucks compared to paying $500-700$ for a chiller is a big savings