Energy free water cooling? Input please

[LED-Freak]

Hey 420 I have an idea and I need to know if it could ever work.

I am putting together a water cooled grow room but I hate the thoguht of using 600+ watts to cool a resv using a chiller.

My idea:

I have a large concrete slab basement. Not used for really anything. It stays cool year round. The floor has a surface temp of 66 degrees in the summer and even cooler in the cooler months. If I run 150ft of copper tubing across the floor bent to resemble a coil and put 6 box fans blowing cool air across and over the copper tubing, will that cool my 55g resv?

Or I was thinking of filling three 55g drums with water and run a 60ft copper cool threw each drum. The drums will be sitting on the cool floor. I like the idea of this one better. Seems like it has a greater potential to cool.

So with 220gallons of water, 180ft of copper coil, a cool floor, cool temps, I think I should should be able to water cool a 10'x10' room for free running 1900w of lighting.

What do you all think? PLus all the supplies will still cost less then a 1/2hp chiller that draws 660w of juice.

 

[crunkyeah]

Sounds very interesting to say the least! What I would do is have the copper piping directly on the floor. Having the drums wouldn't really help since only the bottom surface will have contact with the cool floor. Since heat rises and cool stays on the bottom, you would need some kind of pump to pump the cooler water to the top so there's an even distribution of heat throughout the drum.

The first method drastically increases surface area for the copper tubing to dissipate heat, having the fans would surely help.

Having a reservoir means you're going to need a chiller, which like you said isn't good for the electric bill. Since fans are much cheaper than chillers, just find a way to increase surface area for the copper tubing and point a couple of fans directly on the tubes to further help with the cooling.

I've been looking into liquid cooled systems myself, and from the looks of it the cheapest method is a radiator with heat pipes running through it with a fan blowing fresh air across the tubes. Another important factor here is your pump, it's the core of ANY liquid cooled systems. From what I've gathered, more gallons per hour, more heat dissipation. It's all about the pump and surface area. Maximize these and you should see the results you desire.

Good luck either way

 

[ChicagoJoe]

the cooling effect will create moisture on the copper that will condense and on your floor, just fyi.

 

[Bandit420]

I currently run a water cooled air grow room and I can offer these bits

600watts for a chiller is a huge overestimation of power.
Chiller wattage examples for Hydrofarm/Active Aqua chillers is 150 watts for the 1/10hp, 280 watts for the 1/4hp chiller, and 360 watts for the 1/2 hp chiller

If you need to only cool a res it may stay cool just by having it on that cool floor and shaded from your lighting. Maybe one of those large low profile reservoirs would do the trick. Insulation can also help.
If you need more cooling for the res you could use another smaller res filled with ice water(frozen three liter bottles used as ice cubes) and pump that water thru a titanium coil that is placed inside your growing res to cool it down.

 

[Setting Sun]

Yep, before spending any money, I'd just set the res on the cool cement slab and see how that works.

You need to get as much contact between the res and the cement as possible, so to get the most transfer you need to eliminate any gaps.

A layer of clay or something like that between the res and the cement will give you the best results.

 

[LED-Freak]

Hey thanks for all the input 420!

I put together a little sketch to illustrate my tweaked idea.

Check it out:
I will have a total of 5 steel 55g drums with coils running threw each drum that are all attached to a small 30g resv that will be 75% h20 25% antifreeze which will be a close loop from the 55g drums.( I pick steel drums because of its greater ability to absorb and transfer heat oppose to plastic) I will have some fans also blowing cool 66 degree air all around the drums during lights on.

I thinking this might have enough surface area, enough water, and enough heat transfer to maintain my grow room at 85 degrees. What do you think.

It would be awesome if someone knows a formula that calculates how many BTUs are needed to cool X amount of watts.

Thanks 420 for your input, everything is a help

The way I think of it is each drum will have to have the ability to cool 378w. 1890w of light / 5 drums =378w

I don't know how much heat absorption/transfer energy 55g of water possess, guess Ill have to find out some how huh?

Could you all imagine how nice it would be to place a geothermal loop 20ft under ground? Could have free cooling in the summer and free heat in the winter. (although you would need it really)

 

[LED-Freak]

Now this would kick ass!

 

[crunkyeah]

Going to comment on the most recent post first, that would be extremely cool! Could have tons and tons of heat dissipation through the ground that way. I wouldn't wanna have to pay to have them put in though I'm sure that's a hefty chunk of change.

As to your first design, you will need a pump going from the rez to your lights and ice boxes. Just looking at it, that one pump is going to have to go through 6 different containers and THEN still have enough pressure to go upstairs(assuming the top black line is the ceiling). It would just seem like it would help the flow of water without stressing your poor pump.

Not sure if this will help or not, but this site shows the Thermal Conductivity and Specific Heat Capacity for a bunch of different substances. Water is sky high above air in terms of heat capacity(Air 100°C -1.0, Water - 4.184). This site here might make ya think about things a little differently, since they state 1300w of heat dissipation in those radiators alone. I think your system is scaled up super large to be honest. I'm not sure how large I would do it personally, but it seems 2000w wouldn't be that hard to dissipate in water.

Food for thought

 

[LED-Freak]

Going to comment on the most recent post first, that would be extremely cool! Could have tons and tons of heat dissipation through the ground that way. I wouldn't wanna have to pay to have them put in though I'm sure that's a hefty chunk of change.

As to your first design, you will need a pump going from the rez to your lights and ice boxes. Just looking at it, that one pump is going to have to go through 6 different containers and THEN still have enough pressure to go upstairs(assuming the top black line is the ceiling). It would just seem like it would help the flow of water without stressing your poor pump.

Not sure if this will help or not, but this site shows the Thermal Conductivity and Specific Heat Capacity for a bunch of different substances. Water is sky high above air in terms of heat capacity(Air 100°C -1.0, Water - 4.184). This site here might make ya think about things a little differently, since they state 1300w of heat dissipation in those radiators alone. I think your system is scaled up super large to be honest. I'm not sure how large I would do it personally, but it seems 2000w wouldn't be that hard to dissipate in water.

Food for thought

Thanks man, those sites are awesome. I spend hours reading through books and looking for info like that! I love this damn forum!

And you caught my crappy little drawing error. There will be two pumps used, some high capacity flowtec pumps but at any rate......good eye man and thanks for the solid solid info. You rock +rep

 

[crunkyeah]

Not a problem at all man, glad I was able to help ya out

 

[CBP420]

Water cooled AC is how most big buildings are cooled. If done correctly it is way more efficient. Also why would you use antifreeze/glycol? Are you planning on running the temps below 35? Antifreeze is poison, and it tastes good too.