Water cooled COBs

Joe34

Joe34

Active Member
@ohdang I think you would get significantly better gains by using a fan than using a radiator.

I dont think its a simple as a fridge cools things... Fridges probably work based on the items inside being kept inside over a long period of time, as your constantly moving your water through a pump, its not in there for nowhere near long enough to work how its intended...

In fact, its not going to work at all with a refridgerator, especially not using a minifridge.

Its best to buy a 8-16" fan for like $20
 
ttystikk

ttystikk

Well-Known Member
ohdang said:
Yea i thought of that, but the fridge is kind of small inside, and i was also concerned that the fridge might overcool the water and create condensation on the coolbar/cob assembly.. Will await ttysticks response..
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I'm gratified that I'm considered an authority on this subject, and concerned that I may not be the know it all people think!

I've seen a lot of coolers made from old refrigerators and the results have been mixed; a fridge is designed to maintain a temperature, not move a lot of heat. Their ability to cool ongoing loads is therefore limited. Moreover, putting such a load on one isn't very efficient, again, because it isn't what they're made for.

A small load will probably be okay, but it will more or less amount to just cutting the overall operating temperature by a few degrees. The question to ask is what your target temperature is, and why?

I built a system to maintain the chips at cold temperatures, like 55-60F. That turned out to be TOO cold, creating all kinds of problems on the way to solving one.

What's wrong with running the chips at 120F? Is there a big need to be cooler? If so, what's your target? Maybe the excess heat can simply be dumped into the ambient air beside the tent or maybe outside and save the cost and complexity of the compressor altogether.

There's plenty of options, narrowing them down is best served by figuring out what the desired end result looks like and working backwards.
 
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ohdang

Member
ttystikk said:
I'm gratified that I'm considered an authority on this subject, and concerned that I may not be the know it all people think!

I've seen a lot of coolers made from old refrigerators and the results have been mixed; a fridge is designed to maintain a temperature, not move a lot of heat. Their ability to cool ongoing loads is therefore limited. Moreover, putting such a load on one isn't very efficient, again, because it isn't what they're made for.

A small load will probably be okay, but it will more or less amount to just cutting the overall operating temperature by a few degrees. The question to ask is what your target temperature is, and why?

I built a system to maintain the chips at cold temperatures, like 55-60F. That turned out to be TOO cold, creating all kinds of problems on the way to solving one.

What's wrong with running the chips at 120F? Is there a big need to be cooler? If so, what's your target? Maybe the excess heat can simply be dumped into the ambient air beside the tent or maybe outside and save the cost and complexity of the compressor altogether.

There's plenty of options, narrowing them down is best served by figuring out what the desired end result looks like and working backwards.
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hey tty, thanks for the response.. This whole build has been driven by the need to fit into my current circumstances.. So keeping the cost low, working with available resources... these are high priority. I also will be in close proximity to the tent, so keeping the whole thing relatively quiet and not impacting ambient temps too much is a concern. I like the idea of using water cooling, because in comparison to fans, water pumps are less intrusive to the ears.. Also the builds i've seen here have the potential for cost-cutting and performance enhancing.. Some of the questions you've asked i'll definitely defer to the people with greater experience and knowledge, many of them on this forum. For the temperature, I was thinking that with respect to performance, lower is better(obviously only to a certain point). I've read here that below a certain temperature, the cob bar will be prone to condensation, which is another variable i don't want to add to the mix(which is why I somewhat arbitrarily chose 75F, somewhere just above ambient temps). One of my previous posts I asked some general questions, hoping to get a feel for the math required to calculate the cooling requirements. Not having yet built the rig and decided on all the final components, i just have rough estimates for some of the variables. The first hand experience of others is definitely helpful(thanks again shugglet for sharing). Like I said, if I can make this work by just having a relatively large reservoir(large enough to absorb the heat during lights-on and dissipate it during lights-off), i'm all for it. I have this mini-fridge lying around basically un-used, so I just figured i'd make that MSpaint rendering to share the idea and get some feedback. I was kind of thinking(with reference to the MSpaint drawing) that the pumps connecting the main reservoir and the refrigerated res would only have to turn on periodically, maybe 1-2 times a day with lights on.. Like you said, refrigerators work best at keeping stuff cool, but not constantly being burdened. It just seemed like a decent way, rigged up with a thermostat controller, to keep the temps down but not too low.. I'd love to hear any other advice you might have, or if you have any other resources for me to consider.. Seeing some of the posts from early in this thread have been inspiring to the imagination..
 
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ohdang

Member
thanks @Shugglet , That's making me think that I would definitely need some active cooling of the reservoir If I want to keep temps near ambient, like yours.. I think the maximum size reservoir i could get away with, even outside the tent, is something like a 5 gallon bucket.. Has anyone tried to use this heat to power a sort of distillation apparatus, which could in turn function as drip irrigation for the plants? I know evaporating water dissipates a lot of heat..
 
S

Shugglet

Well-Known Member
ohdang said:
I would definitely need some active cooling of the reservoir If I want to keep temps near ambient
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Yes, and there are sooooo many ways to go about that.

ohdang said:
Has anyone tried to use this heat to power a sort of distillation apparatus, which could in turn function as drip irrigation for the plants?
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Pretty sure @ttystikk collects condensation somehow to feed his plants. Dont think its a drip irrigation though, probably be quite a bit more complex of a task.

ohdang said:
I know evaporating water dissipates a lot of heat.
Click to expand...

True true. Look up "cooling towers" and use that idea to design and build one suited for your purposes if thats the route you choose to go. Personally, I would probably opt for a more closed system with a heater core/radiator and fan, but theyre both perfectly viable. I just dont have any experience in what sort of evaporation youd need to maintain your temps. I cant imagine it would be much though.
 
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ohdang

Member
Shugglet said:
Yes, and there are sooooo many ways to go about that.



Pretty sure @ttystikk collects condensation somehow to feed his plants. Dont think its a drip irrigation though, probably be quite a bit more complex of a task.




True true. Look up "cooling towers" and use that idea to design and build one suited for your purposes if thats the route you choose to go. Personally, I would probably opt for a more closed system with a heater core/radiator and fan, but theyre both perfectly viable. I just dont have any experience in what sort of evaporation youd need to maintain your temps. I cant imagine it would be much though.
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Cool cool.. thanks again.. RIU is an awesome place! Could you list off some of the common methods of cooling, in case i haven't considered any?
 
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ohdang

Member
haha yessss @mahiluana that is an awesome diagram.. Unfortunately the tent is too far away from the water tank in the place I live, so the heat exchanger is out of the question.. But I'm interested in the cooling tower..What are the characteristics of the cooling tower? Basically the idea is just to increase the surface area of the hot water to increase evaporation? Could sticking an air pump and stone in the reservoir accomplish something similar? Or maybe that in conjuction with some aspects of a humidifier(sponge/wicking material and a fan).. Do you think it would be possible to both evap some water and then condense it for drip irrigation? lol that would be awesome.. Thanks mahiluana, I was hoping you were still paying attention to this thread.
 
mahiluana

mahiluana

Well-Known Member
ohdang said:
I'd love to hear any other advice you might have
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*Coolmac* disign for cooling-tower.
---------------------------------------------------
works without additional electricity
As we don`t have "natural convection" we use an outgoing fan tu push air through.
So we don`t need to respect direction of a "natural" airflow.
I put 2 towers parallel to have easy connection
when eg. you cut out ~50cm from your air tube after carbon filter -
and put your ~ 50cm wide cooling tower in between.
You have to collect the water on the bottom and with the air stream you can do more or less, what you want.
Important only to have a big , wet surface inside the tube(best hanging vertically).

eg. °°°°°I_I°°°° or °°°°°I_I°I_I°I_I°°°°°

You can help to find a suitable "surface" inside the tube. Just DIY - and build one
Imo the whole thing should be waterresistant, anti-corrosion and anorganic.
Something - practicable to take it out easiely - give shower and desinfection
and hang it in quickly again.

I will try it with plastic sewage pipes and hanging some nylons of my girl inside.

:bigjoint: ( i like my girl to carry wet nylonso_O)

So time will come, that we are able to cool down water of any amount and temp.
+- without additional electricity.
Together with a dimmable fan, it must be a cheap AC/DC/WC in summer to cool whatever room
or swimming-pool.


I see the only risk in - bad maintanance and bacteria - so take care about your lung :eyesmoke::eyesmoke::eyesmoke:

UOOUUUPS --- just got the idea to plan the inauguration with a gallon of whisky ---
so i will test, if this is a simple, funny way for desinfection - and how long does it take
to vaporize this gallon together with some friends. (:bongsmilie:mrgreen::fire::mrgreen:bongsmilie(:

( DON`T DO THAT WITH GASOLINE - AND OTHER AFTERBURNER !!!)
 
mahiluana

mahiluana

Well-Known Member
ohdang said:
too far away
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:bigjoint: too far to take a garden hose with you ???
when I go to shower I take my double hose(cold/hot)10m and connect it in 20 sec. to my bathtube.

ohdang said:
think it would be possible to both evap some water and then condense it for drip irrigation
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you have to find something with lower temp. than your outcoming air.
Try to pull (a part of) this cold air into your fridge and you will be the rainman
and champion of wet fridges.
ohdang said:
Could sticking an air pump and stone in the reservoir accomplish something simila
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water and airflow always increase vaporization.
when i get out of the water and i`M stoned - my air pump is very little.:hump:
 
ScaryGaryLed

ScaryGaryLed

Well-Known Member
ohdang said:
alright guys.. here is a design i sketched up last nite.. Given that I already have the mini fridge, which i don't really use, I'm thinking this setup might be a good way to keep things inexpensive and keep the temps in a perfect range.. LMK what you think.. too much hassle? Would a pump work when placed in a 35 degree reservoir?
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you aint gonna need a mini fridge to cool this off man. you'll be fine with a 10-15 gallon plastic garbage container. you're cobs aren't going to hit more then 35C, water cooled, the lights are gonna give ~5% to 10% more lumens. the pump will be fine, just use an aquarium pump they are made to run at wamer temps, i.e. aquarium lights and heaters. if you want to go the extra mile you can put a simple 120 mm radiator on the output side of the cobs with a 120 mm fan. you really not going to need it, but helps to keep the humidity levels down; if you put the container in the same room. ideally keep that reservoir in another room but not necessary if you have great ventilation which you should anyhow.

This is the only way i cool cobs if i run them at 70+watts each, which i try not to anyhow. I realize you're better off using a lot of 25W- 30W, high power cobs, with heat sinks and fans than full out 1 cob at 140w like the vero 29 are capable of.If price is in your equation, then heck use 1 cob at 140w. It's OKAY if you cool it.

that's my $0.02, i'm sure a lot of you will disagree, but i'm just talking from experience.
 
ScaryGaryLed

ScaryGaryLed

Well-Known Member
that will work, run 18-6. use a 120 mm radiator if you want. i once heard the guy at the aquarium place tell me if inject bubbles into the water with a power head that helps cool the water too. never tried that, never needed to. i have used one of those slim containers that fits under the bed as a reservoir before too. that works fine if your in a tight space.

the thing here is, it's like cooling a computer CPU, you just need to get the temps down in small space. when i used to cool a cpu i would just use a prefabed kit and that was enough to dissipate 140w. look for those closed looped systems if you want if it's a space issue. But you can do it for much less yourself. keep in mind a car radiator is not that big either, and the amount of water in those systems is a couple gallons at most. water is a beautiful thing.

something like this as ref. https://www.amazon.com/Corsair-Hydro-Performance-Liquid-Cooler/dp/B00A0HZMGA/ref=sr_1_fkmr2_2?ie=UTF8&qid=1490454084&sr=8-2-fkmr2&keywords=h2o+corsair+liquid+cooling&th=1

also think about making a cowl to run over the cobs to help move air over them, otherwise that just going to build up inside that space. you need to move air around them somehow regardless if you water cool or not. the heat tends to build up on whatever heatsink/heattransfer material you use.

good luck bro.
 
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ohdang

Member
ScaryGaryLed said:
that will work, run 18-6. use a 120 mm radiator if you want. i once heard the guy at the aquarium place tell me if inject bubbles into the water with a power head that helps cool the water too. never tried that, never needed to. i have used one of those slim containers that fits under the bed as a reservoir before too. that works fine if your in a tight space.

the thing here is, it's like cooling a computer CPU, you just need to get the temps down in small space. when i used to cool a cpu i would just use a prefabed kit and that was enough to dissipate 140w. look for those closed looped systems if you want if it's a space issue. But you can do it for much less yourself. keep in mind a car radiator is not that big either, and the amount of water in those systems is a couple gallons at most. water is a beautiful thing.

something like this as ref. https://www.amazon.com/Corsair-Hydro-Performance-Liquid-Cooler/dp/B00A0HZMGA/ref=sr_1_fkmr2_2?ie=UTF8&qid=1490454084&sr=8-2-fkmr2&keywords=h2o+corsair+liquid+cooling&th=1

also think about making a cowl to run over the cobs to help move air over them, otherwise that just going to build up inside that space. you need to move air around them somehow regardless if you water cool or not. the heat tends to build up on whatever heatsink/heattransfer material you use.

good luck bro.
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Thanks for your input @ScaryGaryLed .. I have definitely considered the stuff you've mentioned. I mentioned in an earlier post, like you pointed out, that evaporating water can dissipate a lot of heat.. And i have toyed with the idea of using that evaporated water(enhanced by either an airstone, or a wicking material and fan) to either humidify the tent, or to be condensed and used in a drip irrigation.. It's just a concept and i haven't done any of the math or testing.. but it would be cool.
 
ttystikk

ttystikk

Well-Known Member
Another option is to drop the return water back into your garbage can from a height of a foot or two. This will also encourage evaporative cooling.

I agree, the mini fridge is an unnecessary complication.
 
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