Water cooled growroom

Apoplast

Carnivorous Plant Addict
Hello everyone - So, I undertook a large reorganization and rebuild of my both of my growrooms this summer. Essentially, I physically swapped my seasonal growroom (day/night: winter 15/5, summer 30/20) and my highland growroom (day/night 26/16) spaces. It ended up being a ton of work and took longer than I had planned. I did this for a couple reasons. The first is that my highland space was larger than my seasonal, and I needed more seasonal space. The second is a structural issue where I was having condensation problems in my highland space that I could better control in the other location.

But I took this opportunity to upgrade my highland grow space climate control by changing the cooling from a dual exhaust portable A/C unit, to a water cooled growspace. Doing so I am using 1/20th of the power and I am now getting much better temperature control.

Here is a little run down of what this looks like.

This is the heart of the operation, it is a 1/4 HP aquarium chiller. I have the temp set to 9C and it clicks on at 10C.

Water cooling 4 room Nov 2017.jpg

The warm water comes into the unit via a submersible pump, is cooled, and then travels back to reservoir. The reservoir is the largest marine cooler I could fir int there. It is highly insulated and located in the room with the plants, which means I don't have to worry about the heat load from the room impacting the reservoir, and that heat which does leak in comes from the room anyhow.

Water cooling 2 room Nov 2017.jpg

A second set of (not yet insulated) tubing comes out of the cooler to feed the heat exchanger. The water moves via a second submersible pump in the cooler. The heat exchanger is attached to a can fan, and both the fan and pump are plugged into a programmable thermostat (I know if I knew how to, or had time to, program Arduino this could all be done through that with the lights, etc.). Here is the fan and exchanger.

Water cooling 3 room Nov 2017.jpg

I don't have the water temp in the cooler set lower because then I end up with a lot of condensation come out of the exchanger. Were I to do this again, I would use a larger chiller, maybe 1/2 HP. But for now it seems to be working. Next I need to get my mist system setup in there to keep the humidity higher and water the plants better. But for now they look like the are surviving.

Water cooling 1 room Nov 2017.jpg

Thanks for looking!
 

VarunA

Carnivorous Plant Addict
wow. Nice job Alex. Damn. Is the chiller really that much more efficient than an AC? I immediately thought why don't u use an AC. Seems like u already used it before. Is the chiller idea really that much more effective? I think I need to increase the size of my water reservoir to get more effectiveness from my 1/4HP chiller.
 

Apoplast

Carnivorous Plant Addict
Hi Varun - Thanks! What's your setup using a chiller? There are of course a number of factors. I spent a good about of time insulating and vapor sealing the room. Right outside of the foam door is the boiler for my house, and perhaps unsurprisingly that room gets fairly warm. Still, with LED lights, good insulation, a large and well insulated reservoir, and a nice heat exchanger it works okay. The waste heat is exhausted to my garage (which means my garage will no longer freeze). In the summer, the garage gets a bit hot though, and the chiller then has difficulty pushing against the gradient between my set point and the garage heat.

Regardless, because of the specific heat of water (roughly 4.184 J/g K) versus air (1.006J/g K, for dry air for dry air at 1 atm not correcting for temperature), water will always have the capacity to be a more efficient heat source or sink than air. This is why I enjoy having a radiator system in my house and not an HVAC. This essentially allowed me to move from using a 12,000 BTU/h A/C unit, to a 1/4HP (rough conversion to ~636 BTU/h) chiller, which is roughly about 1/20th of the power consumption. As I mentioned, I may need to love over to a 1/2 HP chiller this summer to deal with the garage heat issue (though it could give off more heat, or cycle on and off too quickly). Also, I definitely would have liked to have a larger reservoir, but that's what I had room for.

It was a fun, if not labor intensive, project. I'd love to hear more about your chiller use.
 

VarunA

Carnivorous Plant Addict
I think you are doing it the right way. I am using my chiller in a very inefficient way. There is no insulation at all. The water reservoir is too small (1-2 gallons). The chiller is set to 49F and it turns on every 5 min. I think I am killing it by the regular on and off. I need to get a bigger reservoir for the water. Right now there is only distilled water in there. Perhaps need to clean it up and use a new reservoir.


 

Apoplast

Carnivorous Plant Addict
Hi Varun - You are under some very different constraints there! Glass tanks (with the possibility of being tempered) mean modifications are difficult. I have the advantage of doing bulk air cooling, which you don't there.

Is your chilled water is moved by a submersible pump? Or, does your chiller have an internal pump? Mine does not. Certainly if you have a submersible in there, it exhausts its waste heat directly to the water. Certainly the greater the thermal mass you can achieve the better. It will reduce the cycling (mine already does too much as well), and buffer changes in demand as temperature set points vary or lights go on and off. I have 150 quarts (so about 140L), and I could triple that volume, I would do it without hesitation.

The other thing I wonder about from your photos is that you have the heat from the chiller discharging right next to the tanks. That works with an aquarium because the thermal mass is the water in the aquarium, but in your case my concern would be it making the difference greater between the temperature you want to achieve in the tanks and the ambient air temperature. But again, in your case the constraints are so different. I don't know how you'd get around that.

After all of this (unrequested) advice has been given, I can see from an upper pitcher that your plants are happier than mine anyhow. So, who knows. Maybe I should grow happier plants before I make any claims to have anything figured out. ;)
 

VarunA

Carnivorous Plant Addict
Hey Alex,

Sorry I never replied to the thread. I totally agree with the issues you posted and in fact they were the reason for me breaking down the cooling setup. Not to mention, I noticed that the radiator took up too much space in my limited grow space. On top of that I wanted to replace the AC pump to a DC pump in order to deal with the issue that the water wasn't getting as cold as it used to. I made a mental picture of how I would have ideally wanted to mount the radiator outside the tank with a vent going into the tank. However, I started facing other issues with made me drop the project. Perhaps some day I shall repurpose the chiller once again. I know I need to adapt my setup into a more efficient grow tent or something like that. I think I am done with the tank setups in terms of what can be achieved with them.

V
 

Avery

Carnivore
I have given a lot of thought to the water cooling method...
Personally I had very good results when I used a small chest freezer and a pump/radiators, but there’s a learning curve. In fact, I kinda had a redesign that I was going to share- but I ended up going a different route with the cooling methods for my current terrarium.
I was planning on making a thread- but I “repurposed” the freezer back into a regular freezer... for food... haha
 

Apoplast

Carnivorous Plant Addict
Avery, I've wondered how your cooling was doing. That's one plus in the column for your freezer method - you can repurpose it for food! What are you using now?

Varun, don't apologize. I disappeared off this forum for like 2 years after that post. Also, I totally get that my solution to the problem is hot going to work for space constrains of many folks. I have a big house in the exurbs with a partly unfinished basement. And that's one thing that my solution to the issue requires, space. I'll never have or be able to afford a greenhouse, but I was about to get an unfinished basement (turns out that's cheaper than a finished one - what are people thinking? there is no way a rumpus room is better than growrooms for CP!). I've though about how one could modify the kitchen racks we all use to create an insulated grow tent of sorts with foam insulation board. You could paint the outside to make it look like a cabinet, and go a decorative route a la dart frog rack systems. But I haven't had the need to try it out myself.

I do really enjoy learning about how people solve this challenge though. I'm not sure there is an arena where I get to see the full and impressive creativity of the members of this community on full display than when faced with needing to cool a space. I have learned a tremendous amount from everyone here while discussing this topic on various threads, and had some really great conversations. Really, most of the plants I grow don't need this, and the dirty secret is that most of the space in my water cooler growroom goes to waste. I keep it for two reasons: I don't think about it because it just works in the background, and I had so much fun learning what to do to build it that I am a bit proud of it. I'll admit I enjoy the side eye from, even fellow plant nerds, when I mention I have a water cooled highland tropical growroom I've built in my basement.
 

Avery

Carnivore
Avery, I've wondered how your cooling was doing. That's one plus in the column for your freezer method - you can repurpose it for food! What are you using now?
For my latest build I’m actually using an inline fan with ducting and exhausting hot air straight outdoors through a nearby window and pulling in cold outside air at the same time. In my experience this is an effective way of cooling that I can rely on for a huge portion of the year. Free cold outside air all spring/fall/winter.

For the hottest days of summer I have an air conditioner hooked up that does a fine job of cooling (I’m using a “coolbot” controller with the AC).

My hope was to rely on the AC as little as possible and so far it’s worked well for me! I’ve run this setup for a year already, and should add that I got 0% frozen plants even when temperatures dipped down to -40C :)

As far as the chest freezer cooling goes- I really believe in this method to easily cool a large “exo-terra” style terrarium or quite a bit larger! I’ll have to make a thread and then we can discuss it and streamline the design (if anyone’s interested !!) haha

The problem with the freezer method is that there’s a fair amount of moving parts and labour involved, and all said and done could get a bit pricey. That and you would have to have an apartment sized chest freezer in close proximity to your terrarium, which aesthetically could put people off.
 

Apoplast

Carnivorous Plant Addict
@Avery I think we first met when I was using a can fan and ducting to bring in winter chill to keep my tuberous dews cool for their winter growth period. I agree that's the best strategy. Energy efficient. Convenient. You have no idea how many holes I've drilled in my house. I still use it for my winter growers. But I've found switching between winter air and the water chiller to be... In consistent for my purpose.

But I am now hunting your cabinet design. I will discover your secrets. *cue evil, maniacal laugh*
 

Avery

Carnivore
@Apoplast , absolutely! Actually, the first time I heard of it was digging into old message boards and finding @VarunA ’s setup back in the day. He had a really nice aristolochioides, and several other plants in a terrarium. Unfortunately, there was an “incident” and the plants didn’t fair too well...

But! It was inspiring to see and I thought if I could safeguard against freezing then it should work well. His plants looked so vibrant with the fresh air that I wanted to emulate that, rather than the more typical stale, terrarium conditions.

I’d always found that the more air circulation in a tank, the better, but fresh air seems to have taken it to the next level :)
 

Apoplast

Carnivorous Plant Addict
Yes, you and @VarunA and I have a long history of cooling obsessions. You and Varun have me beat though. Both of your plants are far better than mine. By a country mile.
 

VarunA

Carnivorous Plant Addict
I'm glad my method has in some way helped you guys with your setups. I agree...outside air and rainwater..basically any natural input has been the best for plants in my experience as well. Over the last couple of years, I have quit cooling and I think it is basically at a point where small changes have added up and affected how successfully the plants are growing. If I have to do it again, I agree, I would definitely do either a drier vent/cooling tube from the window to bring in cold air again. I don't know how things are going to change over the next couple of years, but I might have to either upgrade to Avery's cabinet setup or an indoor mylar greenhouse setup. Ideally, I would love to start growing in a glasshouse outside, but that will only happen if I move.

PS Avery, if you do make a thread with more details on your new setup, that would be amazing. I think at this point you have the best looking plants I have seen anywhere growing in these "tank-style" setups. I think you found the zone for these things.
 
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