Props!! You can also get some finned heatsinks for the outside instead of channel...may increase the cooling capacity. When you run a test of the effectiveness of your peltier setup, please post the results...I am itching to know how well they perform, as are others I'm sure......This heat sink I added has room for 4 of them if needed. This is just some scrap aluminum channel left over from other projects - including my Solstrip light fixture. I will attach the cooler modules to the heat sink on the outside of the tote, then attach another piece of the channel to them and add a computer fan for cooling. I have several power supplies from my RC hobby that can run them, so it wont cost much to do this.
Try using cotton for the wick. I've cut up old shirts and used strips.I am having doubts and reservations about the Membrane Meniscus technique.
I decided to run some more tests based on how I plan to setup the Membrane tote. I have been planning to follow the original patent drawings and details pretty closely.
That would be a layer of perlite in the bottom of the tote, with a water inlet on one end and a drain on the other end. The nute solution is supposed to flow slooooly through the perlite. The water level needs to be just at or barely below the top of the perlite. The, the "membrane" sits on top of the perlite. Its purpose is to allow water to wick up to the root zone but prevent the roots from getting into the perlite. The roots are NOT supposed to be sitting in water. Only a thin film of water - the meniscus - is supposed to be touching the roots.
That all sounded good to me, and when I ran my first test of the rip-stop nylon I have using just water, it seemed to work fine. That test was just filling a jar to the top with water and setting the nylon on the top and then placing a cardboard tube on the nylon and seeing the water wick up the tube. That worked ok, but the water was actually touching the nylon in that test.
I put some perlite in a jar and added water almost to the very top of the perlite. Then placed the nylon on that and stick another cardboard tube in there with a small weight to hold it against the nylon and perlite. Wicking does occur, but it is really sloooooooooooooow. Im having a hard time imagining this will be enough water to let a plant grow properly.
So I ran a second test using the silk screen. It lets water flow through it very freely where the nylon does not. The wicking action is much better, but its still pretty darn slow.
It looks like my nylon just doesnt wick fast enough to work, so maybe I have the wrong kind of rip-stop or its too dense or something. The silk screen however, is a lot more porous than what he describes as the perfect material - I think.
Im going to have to go re-read his notes and details to see if I missed something. If it wasnt for the rave reviews I read and pics from several different growers, I would doubt this could possibly work. Actually, Im doubting anyway....
Left is the rip-stop and right is the silk screen after about 15 minutes.
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I did a test on some perlite a couple of weeks ago and I thought it did pretty good. I put about 1/2" of water in a mason jar, then added about 3" or 4" of perlite. Then I placed another cardboard tube just resting on top and it started getting wet in just a few minutes. That meant the water had wicked up at least 3" in just a few minutes.Yea perlite dont wick too well
You might try washing it with soap. It may have some sort of coating to make it water proof or mildew proof. After I washed my nylon, it wicked better - still stupid slow but better. I also washed the silk screen, but didnt notice much difference there. I plan to wash my batting as well.The only thing i didnt like with my mini mock up is that the batting while it dies get wet
Its a little on the hydrophobic side.
I have been busy so i have been neglecting them but i did peek in and the roots are starting to grow through the batting so part one is a success.
But my mini mock up is just a nursery tray so i have reservations about how well water can get into the batting if the water just travels through the troughs without wetting the batting .
Time will tell
The issue is that you had the carboard directly in the perlite so it wicked well. The cardboard probably did more of the wicking cause its such a thirsty materialI did a test on some perlite a couple of weeks ago and I thought it did pretty good. I put about 1/2" of water in a mason jar, then added about 3" or 4" of perlite. Then I placed another cardboard tube just resting on top and it started getting wet in just a few minutes. That meant the water had wicked up at least 3" in just a few minutes.
I think its the fabric Im using that is the issue.
I remember reading somewhere in the docs on the Membrane technique about how he recommended testing the fabric. Now I need to go find that and re-read it.
Excellent idea i will give it a hand washYou might try washing it with soap. It may have some sort of coating to make it water proof or mildew proof. After I washed my nylon, it wicked better - still stupid slow but better. I also washed the silk screen, but didnt notice much difference there. I plan to wash my batting as well.
Ok, you have been holding out on us! We need pics and details - especially on the new idea!Mabey use somthing that wicks easier under the dacron layer.
Rockwool or coco slabs? Then lay the layer over it ?
I just had a crazy CRAZY CRAZY Idea
I just might change my design! Need to go do some drawing now
My CRAZY idea will only work if i find a material that will wick water but NOT let roots through.Ok, you have been holding out on us! We need pics and details - especially on the new idea!
Thats exactly what the Membrane guy says to use.My CRAZY idea will only work if i find a material that will wick water but NOT let roots through.
Ill try to get time to draw up what im thinking later
But if it works... i just solved not needing an airpump or a waterpump (optional for top ups)
Also it would not require any real disposables
But it could all be retarded ha ha
I have toyed around with the idea of using Peltier junctions on a cooling block in-line with my modular Dutch bucket systems. But I am not sure what to use as the cooling block material... Plastic isn't the best thermal conductor and metal will corrode and could mess with the plants, so until I can find a suitable material I have pretty much shelved the idea.I have a tube of 3M 5200. That stuff is rated for below water line use on boats and lasts forever. In fact, I just used some to install a heat sink on the side of the rez.
I added a heat sink on the side of the rez for the future addition of some peltier coolers if the rez temps get too hi.
I think peltier coolers are very 'cool' gizmos and Im actually half way hoping I need to buy some to keep the rez temps down. They are cheap and easy to work with. The cheap ones dont have perfect reviews, but it will still be interesting to try them out to see how effective they can be at cooling. One of the best features is that by simply reversing the current flow you can heat the rez or cool it. I have an STC1000 temp switch that can do the switching automatically. I will be using it to monitor rez temps and - if needed - control the peltier coolers.
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This heat sink I added has room for 4 of them if needed. This is just some scrap aluminum channel left over from other projects - including my Solstrip light fixture. I will attach the cooler modules to the heat sink on the outside of the tote, then attach another piece of the channel to them and add a computer fan for cooling. I have several power supplies from my RC hobby that can run them, so it wont cost much to do this. These can be had for even less on ebay.
All I did was cut out a strip 1.75" wide by 7" tall, then glued the heat sink in with 3M 5200 fast cure marine sealant. That stuff will last forever and not leak.
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The garden spigot is to drain the rez and the 1/2" CVPC pipe is to feed the airlift pump chamber. I'll go over that later when I get to that part.