please help me water cool a room the right way!

Hello all, I am building a fairly large growroom for nepenthes plants as well as heliamphora. I know this is not what most on here are growing but I have tried getting help from hvac boards as well as carnivorous plant boards and have not gotten the information I need to go forward with confidence.

-The room is 8 feet wide, 16 feet long and 8 feet tall.
=The lighting will consist of eight 4 foot 4 bulb t5 fixtures
-every surface will be water proofed and floor will run at a 3 inch pitch with drain on th elow side to catch all runoff.
-There will be a mistking misting system to keep humidity above 80% at all times.
-Temps must hold around 80 degrees during lights on and drop to 50 at lights out.
-The cooling system is where I come to you for help!

I would normally use an ac unit to do the cooling in a ganja grow but have read up on water cooling and the added efficiency of this style. Typical ac units pull the moisture out of the air very quickly and I want to avoid this as much as possible here. Think tropical rainforest.

I have purchased an 8 inch icebox heat exchanger for the watercooled system but am debating between buying a chest freezer that would have a reservoir of water/antifreeze solution and plug it into a temp controller thatd keep it 35-40 rather than below freezing. This would involve cutting into the freezer to get the cold and return lines in and out of the freezer and up to the heat exchanger. The alternative I thought of was to use a water chiller that would keep a separate reservoir at 40 degrees and have a pump in the res that would shoot up to the heat exchanger.

Alll chillers meant for aquariums have very limited options for temp setting. Are there chillers that can drop the temp down to 35-40 or is the chest freezer my only bet? Also, how large of a reservoir would I need to comfortably handle absorbing the heat of roughly 1800 watts of t5? I was thinking 30-40 gallons

Thanks for helping a stoner with a strange secondary growing hobby out!

Never did anything like this so I wouldn't know.......so just taking a stab at this and could be wrong but...

Your probably going to need a heater for starters, that's a big temp change in the morning.

Not trying to change your mind on water cooling but if the only using it is to drop your RH, I don't think its an issue. The water holding ability of 80f to 50f is extreme. Dropping from 80f to 50f is going to be a humidity spike. Water is going to condense everywhere that's warm (lights, plants, walls, ceiling). With an air conditioner, it will pull a lot of water out of the air, but your humidity level shouldn't be changed that much.

Or at least thats what I think. Take it worth a grain of salt.

- Jiji

Just curious what materials are you going to use in your room (walls ceiling), to keep clean and keep away mold and mildew?

Thanks for the input, I figure the lights will heat the space up from 50 to 80 in 2-3 hours. This based on my current setup scaled up to the size this new room. There will be minimal air exchange in and out of the room and the walls will be very well insulated to help keep heat in or cold in depending on the time of day.

The condensation issue is something I will have to address, condensation on the lighting is a very real problem. Do you think running an ac for initial cooldown would help take some of the excess water vapor out of the air as temps drop and reduce condensation on my lighting?

Well after thinking about it was gonna edit my statement, about condensation on the lights or warm things. Its just gonna be everywhere lol.

Ac is going to take a lot of condensation out. But setting up a sealed grow room running 80ish lights on, 70 lights off, is easy to achieve. Getting the RH to 50 percent during lights off requires a fair amount of dehumidification (even when the rh lights on is 60 percent @80f).

No matter how much you insulate certain materials like drywall will mold at +80percent humidity at 80f. FRP would be awesome but it isn't cheap.

- Jiji

I am having someone else build the floor, walls an ceiling. I forget what he said would be used but was told it would resist mold and water very well. Definitely no drywall or plywood for this project. I'll get post what will be used when I get the name of it.

Another way I can try and lower the condensation could be to cut off the misting a few hours before lights out so the air can begin to dry out prior to the cooldown.

anyone else out there with some much needed personal experience with this type of thing?

Wire a humidity control unit to kick on an exhaust fan at lights off.

good idea, thanks!. Do you know of a relatively cheap unit i could plug the fan into to control it? I have temp controllers but not humidity.

I decided to go with a 1/2 hp chiller and a 40 gallon reservoir. A tad bit overkill by design so it can bring the res temp down faster. I'll start with a single 8 inch icebox heat exchanger but feel as though adding a second may be the way to go for a quicker drop.

The product being used is called dryply. Its treated with a water repellent product. Floor is done, walls and ceiling should be up in the next week or two and then I'll get to installing the lights, mist system, and cooling system as well as a ton of small axial fans for airflow.

I thought I was gonna cool a sealed 600-1kw room and minigen co2 generator with a half horse chiller and a 50 gallon res. Didn't happen and used a lot of power in trying it. Considering giving it another go since they say we're gonna have a hard winter.
I'll put the res outside plus run the chiller and see how it goes.
As it was water started at like 39 F and by the time the 12 hour day cycle was over the water was over 70 F.
One 8 inch icebox and a half horse chiller isn't gonna do it for that size of room and wattage.

I don't wanna ask you a million questions on how you had it setup but did you do the proper research beforehand?

My setup will consist of an outer room where the chiller and reservoir will be in a climate controlled 65-75 degrees and I plan to build an insulated shell that the reservoir will fit snuggly into. The reservoir will be kept at 40 degrees 24/7 and the pump to the icebox will only run when the controller clicks on.

I really hope I don't end up regretting this move to water cooling for my project. I'll definitely post results one way or the other.

I recirculated the chiller on a huge igloo cooler 24/7.
From the igloo to another pump thru a thermostat to the icebox and a fan.
I eventually built a couple manifolds from pvc pipe and fittings to increase my water flow.
Nothing really worked well for me . I tried every possible way I could run it but it just didn't work well.
I'm thinking I would need a 1 horse chiller and at least two 8 inch icebox for the small room I run.
There are other alternatives to those expensive little icebox products too by the way. They are handy with that 8 inch round expensive as fuck plastic housing.

I've been scratching my head as to why those damn iceboxes are so expensive.... a brand new 8 inch vortex fan costs roughly the same as the heat exchanger LOL

@ttystikk is cooling his room in a similar manner I believe. He may be of assistance here...

I've never had any issues with my mini split........

- Jiji

Half horse is going to struggle to keep anything more than just the red/RDWC water cold; it just isn't enough capacity. No one is suggesting a 6k BTu AC unit would be enough, so why would it be for a water chilling application?

Water TRANSFERS heat more efficiently than air, which is the heart of the efficiency improvement. It does not make free BTus.

Putting the res outside won't be as effective as you hope, because there is relatively little heat transfer going on. A better move would be to go to the junkyard and get a radiator with the electric fan and shroud still in place. Wire the fan to run anytime water temps in the radiator exceed 60f, and put that on another thermostat that keeps it from running unless outside air temps are below 55. This 'compressorless chiller' will shed heat into the atmosphere whenever it's cold enough. If it freezes in your climate, 20% PROPYLENE GLYCOL, NOT ETHYLENE GLYCOL will keep your lines and radiator from freezing.

thanks for your time, much appreciated.

I'm gunna try and get the chiller order changed from a 1/2 to a 1 horse. Using a 1 or two 1/2s would I want to up the rez volume from 40 gallons or is the volume enough so long as I have enough BTUs to cool it?

Im hoping the cooling setup will only be tested at lights off to get that 30 degree drop. Once dropped, the room shouldn't need much cooling as I'll have the sucker insulated. When lights are on I'm sure it will have to flick on and off as the lights' heat will add up quickly. This will give the unit most of the night to recool the water.

amazing how I went into this project thinking a 1/3 horse would be enough... dumbass

Myles117 said:

Hello all, I am building a fairly large growroom for nepenthes plants as well as heliamphora. I know this is not what most on here are growing but I have tried getting help from hvac boards as well as carnivorous plant boards and have not gotten the information I need to go forward with confidence.

-The room is 8 feet wide, 16 feet long and 8 feet tall.
=The lighting will consist of eight 4 foot 4 bulb t5 fixtures
-every surface will be water proofed and floor will run at a 3 inch pitch with drain on th elow side to catch all runoff.
-There will be a mistking misting system to keep humidity above 80% at all times.
-Temps must hold around 80 degrees during lights on and drop to 50 at lights out.
-The cooling system is where I come to you for help!

I would normally use an ac unit to do the cooling in a ganja grow but have read up on water cooling and the added efficiency of this style. Typical ac units pull the moisture out of the air very quickly and I want to avoid this as much as possible here. Think tropical rainforest.

I have purchased an 8 inch icebox heat exchanger for the watercooled system but am debating between buying a chest freezer that would have a reservoir of water/antifreeze solution and plug it into a temp controller thatd keep it 35-40 rather than below freezing. This would involve cutting into the freezer to get the cold and return lines in and out of the freezer and up to the heat exchanger. The alternative I thought of was to use a water chiller that would keep a separate reservoir at 40 degrees and have a pump in the res that would shoot up to the heat exchanger.

Alll chillers meant for aquariums have very limited options for temp setting. Are there chillers that can drop the temp down to 35-40 or is the chest freezer my only bet? Also, how large of a reservoir would I need to comfortably handle absorbing the heat of roughly 1800 watts of t5? I was thinking 30-40 gallons

Thanks for helping a stoner with a strange secondary growing hobby out!

Click to expand...

Call surna.com. Tell them I sent you.

They're the acknowledged expert in indoor water chilling applications and they can help you with your specific needs, including the maintenance of your overnight temps.

Further, I'm confident that an overnight temperature of fifty degrees Fahrenheit can be achieved with water temps in the mid to upper forties; no heat input means temps fall to approach that of the cooling circuit. Humidity will naturally be very high in such conditions overnight and you may get dew.

Because of the big temperature swing between night and day, you'll need some way to supplement RH if you want daytime temps at 80f and maintain high RH. In the case of high performance growrooms, the plants themselves are the humidification system; for your proposed crop, I'm sure they'll need some help.

cool, i hadn't had much luck finding a company such as this.

yeah, ill have a mistking set to spray for roughly 30 seconds about 6 times each light period. Supposedly their mist heads put out the finest droplets outside of using humidifiers or foggers. I may also run a few ultrasonic foggers in a big rubbermaid tote under a plant bench if the mist isn't getting the humidity exactly where I want it.

got my chiller order changed from a 1/2 to a 1 hp and have a 2nd icebox coming. gunna use a 55 gallon drum wrapped in insulation. Will post pics when it comes together

Good show! Do you have the rest of your water chilling circuitry in place?