Res Cooling: PC Liquid Cooling Radiator Hack

Greetings,

I've been recently trying different methods to reduce my nutrient solution temps and I stumbled across a solution that is quite interesting. I used PC liquid cooling parts as a radiator through which I continually circulated my solution. Thanks to the second law of thermodynamics, radiators are an effective solution for transferring heat. Plus I figured a CPU was a hell of lot hotter than my reservoir, so it was worth a shot.

I conducted a simple test with a single 3-gal bucket and a submersible pump. The pump, when run continuously, heats up the liquid in the bucket pretty consistently (this was also true for an external pump, which I initially thought might solve the heat problem, but didn't).

These are the materials I used in the test:

Bucket: 3-gallon black (w/ lid loosely attached)
Water Vol: 2 Gallons (US), tap water
Pump Type: EcoPlus 185gph Submersible
Tubing: 1/2" poly x 4' (mostly outside of the bucket.. see pics)
PC Radiator: EX240 Dual Fan Radiator (~$40)
PC Fans: 120mm generic pc fans x 2 ($5/ea)



The Tests:

[Note: the temperature margin of error is probably: +/- 1ºF]

• Pump Only
  • Run Time: ~8hrs
  • Ambient Air Temp: 70ºF
  • Begin Water Temp: 70ºF
  • End Water Temp: 79ºF
  • Difference: +9ºF

• Pump + Radiator (No Fans)
  • Run Time: ~8hrs
  • Ambient Air Temp: 70ºF
  • Begin Water Temp: 70ºF
  • End Water Temp: 71ºF
  • Difference: +1ºF

• Pump + Radiator + Fans
  • Run Time: ~8hrs
  • Ambient Air Temp: 71ºF
  • Begin Water Temp: 71ºF
  • End Water Temp: 72ºF
  • Difference: +1ºF

These tests show the radiator easily dissipated the heat generated (+9ºF) from the pump running continuously. The radiator fans didn't seem to have much impact in these tests. But certainly their value would become quickly apparent with higher starting temps.

Anyway, seems like there's some potential here. What do you guys think??

Good deal dude.
Me, being a mechanic, have thought about that when I see titles of posts about how to cool a res, but being a soil guy, I didn't think twice about it.

Very cool. My first thought though is you have to have the ambient temp to make it work and most rooms should be running 76-84 depending on setup which would raise the res temp faster.

this idea sounds like a dream come true, But as stoner stated the ambient temps are vital and come summer my rooms are usually in the 85s to 90s. My concern is more so the copper and brass core affecting metal in the nutes.

I've got it running now in my veg room where it's about 77ºF ambient. Fans are running on the radiator. Nutrient temp hovering at about 72ºF. I do have airstones running in the system, which could be helping to bring the nute temp down some as well. But it's definitely cooler than if it were running without.

One thing to consider, the tubing to/from the radiator could be run a decent distance from the grow area. If you don't try to climb stairs or use 100' of tubing, one could conceivably place the radiator outside the grow area in a location with lower ambient temps.

@ounevinsmoke Re: the metal materials used... that is (still) a bit of a concern to me as well. The radiator housing seems to be cast.. most likely galvanized steel, which is not food-grade material by any stretch. Copper is safer (used in making booze, for example), but could still potentially impart unwanted impurities.

One alternative approach which could be considered is some copper tube in the res connected to the radiator outside. Then water or coolant is pumped continually through this closed-loop system to draw off excess heat.

Back when I was researching DIY Chillers not too long ago most people were using copper wort chillers combined with small dehumidifiers and altering it, turning the condensers to chillers. At first they were using copper wort chillers directly inside the res and thats where there problems started. They said the copper in the res does something to the metal in the nutrients causing lockout and deficiencies. They fixed the problem by using stainless steel wort chillers. So the DIY chiller is a separate system itself with only the stainless steel wort chiller emerged in the tub with your plants. Cold water running through the wort chiller to cool the nute soup. I never ventured and created my own I just learned how to grow in warm water. People swear it cant be done but My water stays in the upper 70's to low 80's and no slime, root rot, or any other deficiency. Its all about the method in my case.

nameno said:

• I just learned how to grow in warm water. People swear it cant be done but My water stays in the upper 70's to low 80's and no slime, root rot, or any other deficiency. Its all about the method in my case.
  
  Tell us what your method is?​
  
  

Click to expand...

Its really no secret or anything fantastic, I find the best clones and when I grow I only keep the most stress resistant strains. Then to make sure my roots can handle the warm climate I veg longer until I get thicker stronger roots. In my case the thicker roots seem to be more resistant to not so ideal conditions. I switch my growing methods with the season because I dont have complete temperature control in my grow room. I have HID lights and florescent. One during the summer and one during the winter. Dont get it twisted though, I do know how to effectively battle slime or root rot if I ever had the problem.

ounevinsmoke said:

Back when I was researching DIY Chillers not too long ago most people were using copper wort chillers combined with small dehumidifiers and altering it, turning the condensers to chillers. At first they were using copper wort chillers directly inside the res and thats where there problems started. They said the copper in the res does something to the metal in the nutrients causing lockout and deficiencies. They fixed the problem by using stainless steel wort chillers. So the DIY chiller is a separate system itself with only the stainless steel wort chiller emerged in the tub with your plants. Cold water running through the wort chiller to cool the nute soup. I never ventured and created my own I just learned how to grow in warm water. People swear it cant be done but My water stays in the upper 70's to low 80's and no slime, root rot, or any other deficiency. Its all about the method in my case.

Click to expand...

I made my own chiller using an old dehumidifier. I removed the evaporator (part of the system that gets cold) and replaced it with a stainless steel coil which I housed in a piece of 4" PVC pipe, fittings in and out and I circulate nutrient solution directly through. I have the hvac tools and knowledge to do this, though. Stainless is the way to go. Retail aquarium/hydroponics chillers use titanium because of it's superior corrosion resistance, better than stainless. However, some types of stainless have better thermal conductivity than titanium and titanium is about 3x the cost of stainless. I have seen stainless corrode and rust in salt water aquariums. For our application stainless is perfectly acceptable. Supposedly even some types of copper are acceptable, special alloys and types without anti-corrosive additives... I won't even go there since I do not have enough knowledge to lend credit to it. I have wondered how hard chromed copper would work, though... Copper tubing is half the price of stainless and has a thermal conductivity that is about 20x that of stainless/titanium. There is a company that does metal plating with a special solution called Armaloy. I tested a piece of copper plated with this stuff in a very strong (much stronger than we'd ever dare to use) nutrient mixture and there was no tarnish or oxidation at all to the plating.

All that being said, I definitely would NOT be using a PC radiator. They're made with a copper alloy that WILL corrode and impart toxicities to your nutrient solution. They're made on the cheap in China and designed to be used with distilled water and/or anti-corrosive additives such as Water Wetter or propylene glycol (anti-freeze). I've been running PC water cooling for 10+yrs now and have made direct-die refrigeration cooling systems for PCs, etc... I have a bit of experience when it comes to this.

** The other day I cut a small piece of 1/4" copper refrigeration tubing and dropped in it a cup of tap water and liberally added GH FloraBloom and a high nitrogen fert... So far the copper has not tarnished or oxidized at all. Looks just like it did when I started. Like I said, I've heard that some types of copper "may" be safe... I'm interested in seeing how long this piece of copper stays shiny. If it is being attacked it'll be obvious as it will tarnish and ultimately turn green.

For anyone who stumbles across this later.. be sure to avoid copper or galvanized as they will leech and kill your plants, as is now well known.

Seems there's a new commercial version of what I built... Claims to cool up to 30gals about 6 or 7°F
But for $220 USD... might as well get a refrigerated cooler.

CSXC-1 Aquarium / Hydroponic Chiller
http://www.chillsolutions.com/products/csxc-1-aquarium-chiller

Not a bad idea, however.. could the same thing be done with a fan blowing on the bucket?.. Plastic will still transfer heat fairly well, and if the goal is to simply match the room temp with the ambient room temp you could do the same...

Now I see some comments about interaction with copper or galvinized metals.. And I somewhat agree, what you could do is make the cooling system closed loop, and add extra cooling coils with a long stretch of PVC hose put those in the tank/bucket and use distilled water as your coolant, so it will act as a heat sink.

I say this mainly because I dont use any fancy cooler, however I flow cool intake air over my res, its around 50 gallons, and with ambient room temps around 85 degrees I have no problem keeping 65-70 res temps. My intake air is fairly cold so I dont have too much problems with it.

diggabyte said:

I've got it running now in my veg room where it's about 77ºF ambient. Fans are running on the radiator. Nutrient temp hovering at about 72ºF. I do have airstones running in the system, which could be helping to bring the nute temp down some as well. But it's definitely cooler than if it were running without.

One thing to consider, the tubing to/from the radiator could be run a decent distance from the grow area. If you don't try to climb stairs or use 100' of tubing, one could conceivably place the radiator outside the grow area in a location with lower ambient temps.

@ounevinsmoke Re: the metal materials used... that is (still) a bit of a concern to me as well. The radiator housing seems to be cast.. most likely galvanized steel, which is not food-grade material by any stretch. Copper is safer (used in making booze, for example), but could still potentially impart unwanted impurities.

One alternative approach which could be considered is some copper tube in the res connected to the radiator outside. Then water or coolant is pumped continually through this closed-loop system to draw off excess heat.

Click to expand...

If your ambient temp is 77, your radiator is ADDING heat to your 72 reservoir. Or your gauges are off.

I had the same idea about running the water through a small radiator, but mounting it to the front of my window ac I use in my grow room, then I realized it might corrode the inside of the radiator to run salt based nutrients through it. So, what I ended up doing is making a coil out of 1/4" stainless steel brakeline and placing it inside the vent on the ac. Just hooked a it up to a small pump to recirculate water through it. Worked out pretty good, so far the water is down to 64.9 I imagine it would also work great or even better if you used 3/8 stainless steel tubing and put the coil in a Styrofoam cooler full of ice and water. That way you'd have to fill it every morning though. I do plan on getting some foam insulation for the clear part of the waterline so the algae doesn't get any ideas and I'm sure it would help keep the water cooler between the coil and its return to the reservoir. And in case you're wondering, I didn't really worry about mentioning air temperature because I have the ac on blast the whole time and just increase/decrease ventilation to keep the room around 77°. And I only have about 15 gallons of water in a single tote with the water pump and two airstones. There's also something I've come up with since I started writing this and I even started acquiring the stuff for it. I am setting up a 4 site plus res rdwc with 17 gal totes and I don't think the small coil in an ac will suffice. I bought a small redbull refrigerator on offerup for $20 and I'm going to buy a 50' 3/8" stainless steel coil for chilling keg beer that fits inside the refrigerator and run my in and out lines to it through some holes in the side. I can regulate the temp with a temperature timer type thing that shuts the fridge off when the water temperature reaches a certain preset point and turns it back on when it rises to a preset point. Just put the probe in the water and hook the fridge up to the device and viola. A stable self sufficient water cooler that really doesn't require much maintenance at all like the ice method or a bunch of wasted cold air through ventilation. I was going to delete the first part of this, but hell I'll leave it in case it helps someone with the idea they may need to get something going.

I was thinking about it and realized that it would actually be kinda dumb to hook the on off temperature activated thing to the fridge instead of the water pump that recirculates the water through the coil. With the water not flowing through the coil in the refrigerator would allow the coil to get really cold thus bringing down the temperature more efficiently once the pump kicks back on. Of course I'm putting the cold water out in to the reservoir and the temperature probe in the last bucket in line. That way it would be more accurate to the overall temperature in all the buckets/totes. Sure the water in the res would be much colder than the last bucket that drains back to the res. I'll shut up now I've said enough

Thats cool. Good thinking, I dig the test results.

I've been using a 6 inch fan to cool my water for almost 5 years. It will cool as much as 20 degrees in a dry/hot environment and can be controlled with the use of a repeat timer. Downsides are: it doesn't work well in a humid environment, and may add humidity to the existing environment.

I bought a chiller for a 50 gallon rig, but it showed up hammered, and had to be returned. I need to do something so I went with the following.

This video was made for a friend on another forum. It has a little more than I need to highlight what I'm saying, but it'll work.


I dig your DIY method. We need more of that