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Post by Apoplast on Feb 5, 2017 22:20:23 GMT -5
Hello all - So, I am currently (well not right now, but in the summer) cooling my highland grow room with a 12,000BTU dual exhaust portable A/C unit. It's way more than I need because I use LED lights which produce very little waste heat. Plus the A/C decreases the humidity, which is of course not ideal for the plants. I've started to explore the possibility of getting a liquid to air process chiller, like are used to cool aquarium water, along with a heat exchanger to with a can fan to cool my grow space. I've been lurking a few forums where they know grow rooms, though are a bit more worried about stealth growing than I am. It's not entirely clear if it will work for my 2m x 2m grow room, because they tend to use them on air cooled HID lights and not entire grow rooms. I'm pretty sure I produce fewer BTUs in the entire room than a single 1000w HID does, but with the greater air volume I'm not clear how well this will work. If it does work, I have a contained cooling device that will be able to bring my night time temperatures lower than my A/C can, using less power, while leaving the humidity higher. My concern is that I'll end up spending a bunch of money on a chiller and it won't work. Plus, I have concerns about the condensation that will surly be thrown off the exchanger. I'm curious if anyone here has experience with these types of cooler systems to cool an entire room? I know Avery has something like this with a chest freezer for a terrarium, and it's amazing! But, does anyone know if this working for cooling a full room? Any stories of experience welcome. Thanks all!
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Post by WillyCKH on Feb 5, 2017 22:33:11 GMT -5
A way to do it, is to take apart a refrigerator, run a fan & air hose to the ceiling of your little grow room, and let the cool air flows down naturally. Of course you will need a temperature control device to switch on and off the refrigerator, but you will also have full control over the temperature range as an advantage. I'm not experienced at all, but if I were to try cooling a small grow room, that'd be my first approach because refrigerator is pretty common, and doesn't use too much energy while being good at its job. Willy
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Post by Apoplast on Feb 6, 2017 19:46:26 GMT -5
Hi Willy - I know Avery does this with a freezer for a small setup. The issue is that retail fridges and freezers are essentially low powered chillers in very insulated boxes. They can't take a continuous heat load of any significance. If I recall, Avery gets around this for his setup by loading the freezer with a lot of water, creating extra thermal capacity. Retail freezers run a few hundred BTUs. A 1hp chiller can do a couple thousand BTU's. Much larger than 1hp and you get into tonnage of cooling, where the chillers are cost prohibitive. My portable A/C unit is a 12,000BTU unit, and more than the room needs. Plus the chiller and heat exchanger should be more efficient. This still leaves me with uncertainty about whether the chiller system will work, or whether I will waste $1K+ on something I can't use. I am fairly confident that neither a retail fridge or freezer will work for the size of my application.
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Post by lloyd on Feb 6, 2017 20:07:54 GMT -5
What about a reservoir of water (maybe a big garbage bin). You could have a radiator with a fan outside to cool the area. Pipes connecting to a radiator inside the bin to dump heat into the water reservoir. If the water got too warm, you could just replace it with tap water. You could even use the warm water to wash your dishes or give the dog a bath. It should take quite a while to heat up the large water mass. Low tech and cheap. You could always try it. The radiators and fan could always be used in a fancier set up if this proves inadequate.
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Post by WillyCKH on Feb 6, 2017 20:21:19 GMT -5
That's good point, sorry that I wasn't helpful. You should try what Lloyd suggested, if it works you can make an automated water pump device that moves the water from the warm to cool, and from cool to warm. Willy
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Post by Apoplast on Feb 6, 2017 23:05:57 GMT -5
Hi Willy - No need to apologize. I love that you are always willing to lend a hand and help out. You've been taking point on Plant of the Month for a while, and are always encouraging. It's awesome! I've done a few calculations on this, and I'm still feeling a bit uncertain. Hopefully someone here as set up something similar. We'll see. If not, and I end up doing it, I'll let everyone know how it works out. Or doesn't.
Hi Lloyd - Don't worry, a large reservoir is part of the equation. I'm looking at using about 40 gal marine cooler as the reservoir. To get an efficiency I need I'm thinking I'll need about a 10C difference between desired air temp and the reservoir water temperature. So if I wan to get down to 13C at night, I'll need to chill the water down to about 3C. My well water is about 5C, so I don't think it will work. But the chillers I am looking at can get down to 3C no problem. The issue I am facing is partly the heat load, and partly the heat transfer capacity of the exchanger. At this point, barring a true summer BTU calculation, I am starting to think I'll need to just try it and hope I'm not wasting money. Yikes!
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Post by shoggoths on Feb 7, 2017 9:02:02 GMT -5
I don't have any knowledge on what as been said before so I can't comment but I would like to add a bit of reverse engineering.
If the problem only comes from the humidity drop, you could perhaps consider segregate your plants from the AC unit. I mean, you could put the AC unit in the center of the room and put your shelfs along the walls. In front of the shelfs, you could put plexiglass or glass board on rail (like a glass walls shower). Ideally, from floor to ceiling for a nice look. When you want to look or water your CPs, you slide one pannel over the other one. It would look like the fridge in big grocery. You would need to take care when insulating the rail and between the pannels to be sure to keep the humidity high on the plants side ...
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Post by WillyCKH on Feb 7, 2017 11:08:43 GMT -5
Hi Alex, Just an idea here, how about instead of getting rid of the AC, add a water fall? It would increase the humidity and would look pretty nice in the growroom if done correctly Willy
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Post by Apoplast on Feb 7, 2017 21:33:37 GMT -5
Merci shoggoths et WillyCKH! One of the things I love about this forum is all of the creativity. The humidity drop is pretty severe with a dual exhaust A/C (part of their benefits in a home!), plus because it is overpowered for the space the condenser cycles on and off far too frequently which can damage it. Plus to be honest, I kind of want to try this. If it works as well as the folks that are using grow rooms for crops say they do, it will make my plants much happier. I do love apparatus!
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Post by WillyCKH on Feb 7, 2017 22:07:47 GMT -5
You have my full support, do it
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Post by Apoplast on Feb 8, 2017 21:16:08 GMT -5
Hi Willy - Glad to hear it!
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