# Using car radiator as cooler



## Progen (25 Feb 2017)

I'm in the tropics and my tank is in the bedroom of a two storey house so it gets a bit warm but I like having the tank right next to my bed so moving it downstairs is out of the question.

On most days, temperature is somewhere in between 29 - 31 and that's on the high side. Now it's not exactly death dealing high and I really can't afford to get a chiller for my 4' tank so I was wondering whether it's possible to pipe the water from my canister's output through an (new of course) aluminium car radiator and have a fan blow on it. I should be able to get 2 - 3 degrees of cooling, right? I've read on a few sites that as long as pH stays above 5, the aluminium won't leach anything toxic into the water passing through. Are there any other dangers which might pop up?

ps. I've seen nice stainless steel room radiators in the U.K. but it's kind of impractical to order them into Malaysia because the moment Customs sees so much metal, there'll be a hefty tax on it regardless of what its final purpose is to be.


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## ian_m (25 Feb 2017)

Wont work in fact you will end up heating the tank water even quicker by putting it through a radiator. If however you ran water across the radiator and blew a fan that would work, but probably not much better than just fitting a fan to top if the tank.


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## xim (25 Feb 2017)

That will not help much because the best that method can do is just lower the water temp down to room temp. 

On the other hand placing a cooling fan(s) above the tank water can make the water cooler than the room temp by evaporation effect.


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## Progen (25 Feb 2017)

Oh, I thought that having a fan blow through the fins of the radiator would bring it slightly lower than room temperature?


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## Tim Harrison (25 Feb 2017)

No...because of the latent heat of evaporation. Check this out 
https://www.ukaps.org/forum/threads/stupid-heat-wave.37627/#post-406360


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## xim (25 Feb 2017)

Progen said:


> Oh, I thought that having a fan blow through the fins of the radiator would bring it slightly lower than room temperature?



No because there is no evaporation. Evaporation is required to get lower temp than the room temp.


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## Progen (26 Feb 2017)

Thanks, guess I've missed too many physics lessons.


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## limz_777 (26 Feb 2017)

cheapest head-start way to cool your tank is to get a used mini fridge ,mod drill  two holes, run a coil pipe thru it , in and out into the tank , for small volume tank peltier cooling is used


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## zozo (26 Feb 2017)

limz_777 said:


> mini fridge



Haha awsome idea, never thought of it.. Thanks for sharing.. Did watch a review video of this one




They perform realy well, with an average of 8°C on hot days.. 50 watt 220 VAC and 12 VDC.. It actualy can also heat up to 40°C with a switch on the back side.. 14 litre volume.. And actualy not very expensive..


This one is even smaller..


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## rebel (26 Feb 2017)

At low pH, aluminium may cause issues with livestock. I would avoid aluminium at all costs. Stainless steel or go home. 

Check out cheap peltier coolers
http://www.ebay.com.au/itm/Mini-Fis...hash=item2a72410287:m:mbkSNROMMt7tc1rPTaeLI9A


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## xim (26 Feb 2017)

limz_777 said:


> cheapest head-start way to cool your tank is to get a used mini fridge ,mod drill  two holes, run a coil pipe thru it , in and out into the tank , for small volume tank peltier cooling is used



I've heard much about using mini fridges. But there is also some info against using it to cool an aquarium. Their reason is a fridge is designed to cool a sealed area. When you close the door, much of the heat from outside can't affect the inside of the fridge. This way the compressor can be small and doesn't consume much power. But if you use it with an aquarium, the compressor will be running non-stop and will fail soon.

http://www.beananimal.com/articles/dorm-fridge-aquarium-chiller.aspx

I've not tried it myself but I think it makes sense.

For the peltier cooler, I've an impression that a 4-ft tank is too big for it to work.


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## KipperSarnie (26 Feb 2017)

Looking at this from a different point of view.
When I was a child we had terracotta milk coolers.
The milk was placed in a saucer / pot of water with a terracotta dome over the top,  The water from the saucer would soak into the terracotta & evaporate thus cooling the interior where the milk was.......  Now could this not be possible run a pipe in the interior of the terracotta dome with aquarium water passing through it instead of the milk bottle?
Perhaps get a dome made or find a porous pipe to do the job.

Oh well! ....  just a thought!  But no running costs if you already have a filter running.


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## Parablennius (26 Feb 2017)

rebel said:


> At low pH, aluminium may cause issues with livestock. I would avoid aluminium at all costs. Stainless steel or go home.
> Quite right, your best bet here is a Lager or beer cooler, the kind used in the basements of pubs. Get a second-hand one. Cooling is secondary, in an "ice bank" where you can use a powerhead to pump tank water through the stainless, food grade coil. Throughput will be slow, but hey, more dwell= more heat exchange! I used these for keeping native marines cool without issue except that they do generate a bit of heat themselves.
> 
> Check out cheap peltier coolers
> http://www.ebay.com.au/itm/Mini-Fis...hash=item2a72410287:m:mbkSNROMMt7tc1rPTaeLI9A


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## Henry (26 Feb 2017)

Why not just counteract the effects of high temperatures by increasing oxygenation with a few airstones? Fish are pretty adaptable.


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## limz_777 (27 Feb 2017)

xim said:


> I've heard much about using mini fridges. But there is also some info against using it to cool an aquarium. Their reason is a fridge is designed to cool a sealed area. When you close the door, much of the heat from outside can't affect the inside of the fridge. This way the compressor can be small and doesn't consume much power. But if you use it with an aquarium, the compressor will be running non-stop and will fail soon.
> 
> http://www.beananimal.com/articles/dorm-fridge-aquarium-chiller.aspx
> 
> ...



yes , already mention peltier cooling is for small volume tank ? 

not sure seen a few diy like this , for those who cant afford to buy a chiller ? besides fan evaporating cooling , nothing much in the market works as well as a aquarium chiller


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## Progen (27 Feb 2017)

Henry said:


> Why not just counteract the effects of high temperatures by increasing oxygenation with a few airstones? Fish are pretty adaptable.



Not likely to do much in my situation. I already have quite a bit of evaporation going on through vigorous surface agitation. My spray bar is made up of 4 pieces and comes up to about slightly more than 2'. It's about an inch below the water surface and is angled towards the surface so that the plants at substrate level are swaying about gently.

I suppose I could go modify a table fan so that it rotates at a slow speed and mount it above the tank or does someone have any better ideas? To be frank, I'm a tight-fisted bugger when it comes to electricity guzzling appliances so it's actually not the cost of the chiller which bugs me.


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## KipperSarnie (27 Feb 2017)

Evaporation of your tank water won't cool it, just drop your water level.
you require evaporation of a different liquid that will cool a chamber.  i.e. a fridge


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## xim (27 Feb 2017)

KipperSarnie said:


> Evaporation of your tank water won't cool it, just drop your water level.
> you require evaporation of a different liquid that will cool a chamber.  i.e. a fridge



It does cool the tank water down, in my experience. 28.5°C in 32°C room with lights on for a 340l tank is possible (with 5 litres of evaporation a day).
Someone may do a bit better than this but I think this is near the limit for fans-on-tank method.


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## xim (27 Feb 2017)

Progen said:


> I suppose I could go modify a table fan so that it rotates at a slow speed and mount it above the tank or does someone have any better ideas?



That sounds good because small fans are very noisy. Just make sure it doesn't drop into the tank.


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## ian_m (27 Feb 2017)

Many people have made quite effective tank coolers by mounting a load of PC fans into the hood of their tanks. If you run large diameter 12V fans on +5V, they run almost silently and can easily lower the water the water temperature a couple of degrees.

One particular summer, here in UK, when it was once hot, I lowered my tank temp from 32'C odd to about 26'C by just attaching a clip on fan (about 15cm diameter) to tank edge.


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## KipperSarnie (27 Feb 2017)

I just love it when I'm right!
but
I'm wrong again!


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## limz_777 (27 Feb 2017)

KipperSarnie said:


> Looking at this from a different point of view.
> When I was a child we had terracotta milk coolers.
> The milk was placed in a saucer / pot of water with a terracotta dome over the top,  The water from the saucer would soak into the terracotta & evaporate thus cooling the interior where the milk was.......  Now could this not be possible run a pipe in the interior of the terracotta dome with aquarium water passing through it instead of the milk bottle?
> Perhaps get a dome made or find a porous pipe to do the job.
> ...




i got to know of this primitive method of cooling some time back , which some call it zeer pot cooler , so  far i didnt see anyone run some test on it on a aquarium set-up ,might be interesting thou.


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## Progen (28 Feb 2017)

ian_m said:


> Many people have made quite effective tank coolers by mounting a load of PC fans into the hood of their tanks. If you run large diameter 12V fans on +5V, they run almost silently and can easily lower the water the water temperature a couple of degrees.
> 
> One particular summer, here in UK, when it was once hot, I lowered my tank temp from 32'C odd to about 26'C by just attaching a clip on fan (about 15cm diameter) to tank edge.



Now that's something worth trying although what was the dimension of that tank? Mine's a 48"er.


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## ian_m (28 Feb 2017)

Progen said:


> Now that's something worth trying although what was the dimension of that tank? Mine's a 48"er.


Yes it was PC fans on a large tank, possibly 4-5 foot.

Only other thing is evaporative cooling, ie air flow across the surface only works in dryer climates, absolutely no good in the tropics as the air is already saturated with moisture, thus will not be able to take any more. The only solution in this case is proper refrigeration or for smaller tanks Peltier type devices.


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## xim (28 Feb 2017)

ian_m said:


> Yes it was PC fans on a large tank, possibly 4-5 foot.
> 
> Only other thing is evaporative cooling, ie air flow across the surface only works in dryer climates, absolutely no good in the tropics as the air is already saturated with moisture, thus will not be able to take any more. The only solution in this case is proper refrigeration or for smaller tanks Peltier type devices.



It still does some good. The air there are not really THAT saturated with moisture. (How can I know? ).
In the rainy season, the evaporation rate will be lower but the temperature in this season will be cooler as well.
Actually, it is in the rainy season (there is no winter), especially around Nov-Dec when the temperature is at the lowest, that a non-chiller planted tank in this region looks at its best.
Final photos will be taken well before the summer comes in late Feb.

Fans absolutely help. I believe the OP could find some fellows in the same region for this kind of info.
http://www.my-mac.net/forum/viewtopic.php?t=1704


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## limz_777 (1 Mar 2017)

xim said:


> It still does some good. The air there are not really THAT saturated with moisture. (How can I know? ).
> In the rainy season, the evaporation rate will be lower but the temperature in this season will be cooler as well.
> Actually, it is in the rainy season (there is no winter), especially around Nov-Dec when the temperature is at the lowest, that a non-chiller planted tank in this region looks at its best.
> Final photos will be taken well before the summer comes in late Feb.
> ...




off topic , but what happen to mac ? used to be one of mine goto forum .


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## Bolota (1 Mar 2017)

latent heat is the amount of heat the atmosphere will gain from the evaporated water vapor mass. The only change in the water side is a reduction of mass and of the total heat of that system (the tank) but it will not lower the temp of the water in the tank..... 
To put it in simple terms: if you evaporate more, you transfer more water (in vapor form) to the atmosphere and that water will contains heat that passes from the tank to the room atmosphere. But the temperature of the water that remains in  the tank is the same.


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## ian_m (1 Mar 2017)

Bolota said:


> But the temperature of the water that remains in the tank is the same.


Incorrect. The energy needed to supply the latent heat of vaporisation to evaporate the water, is supplied from the tank water. Thus energy is removed from the tank, lowering its temperature.

This is why we sweat, the evaporating water on our skin removes energy from the body, lowering out temperature.


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## xim (1 Mar 2017)

limz_777 said:


> off topic , but what happen to mac ? used to be one of mine goto forum .



No idea. May be from competition from other platforms such as Facebook like many message boards . BTW, aquaticquotient.com is still active. Some MAC's members post there too. But today the system is down and seems to lose recent data from Dec last year up to the present. Yesterday it was still fine.


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## Bolota (2 Mar 2017)

ian_m said:


> The energy needed to supply the latent heat of vaporisation to evaporate the water, is supplied from the tank water. Thus energy is removed from the tank, lowering its temperature.



Yes, that is right. I'm sorry. There is an amount of heat you will pay to provide the kinetic energy for the particles to escape the water surface. However, you also loose heat with the water mass itself into the room atmosphere, so the total is maintained (that's what I should have said in the begining). Anyway, my point is that evaporation is only efective if you evaporate a lot. But that only happens if the room temperature is too high and/or too dry. But in that case you have temperature flux back into the water by contact and radiation.... So I cannot believe the fan method to be very efective in a closed room.


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## roadmaster (2 Mar 2017)

I once saw such a DIY chiller made from old portable fridge.
Extensive coiling(see meter's) of tubing ( plastic) inside the fridge, gave longer dwell time for cooling of water passing through the coiled tubing.


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## ian_m (2 Mar 2017)

roadmaster said:


> I once saw such a DIY aquarium chiller made from old portable fridge.
> Extensive coiling(see meter's) of tubing ( plastic) inside the fridge, gave longer dwell time for cooling of water passing through the coiled tubing.


I saw it too, but it was hopeless and didn't really work. Issues were:

- Fridges aren't designed to run the compressor 24/7, thus would not have a very long life.
- Fridges/freezers are designed to produce a temperature drop of 20'C (or 40'C for freezer) and aren't very efficient lowering the temperature the 10'C needed for an aquarium.
- Not very energy efficient running 24/7.
- Not very efficient transferring the "cold" of the fridge to the circulating tube (as it is plastic, not metal).
- Freezing up of internal cooler pipes occurred as not really transferring the "cool" out of the fridge very well.
- Well massively large for the limited poor cooling it provided.

So a proper chiller is the order of the day.

Someone hooked drinks cooler to his tank somewhere, but apart from being very large, very noisy and consumed 1KW power (a chiller is in order of 100-200W) did cool his tank.

As for someone above who said fans don't work, you need to tell the people selling fan kits
http://charterhouse-aquatics.com/sh...ms/jbl-8/jbl-cooler-300-aquarium-cooling-fans

These appear to match what I got in the summer 4'C drop using a clip on desk fan.


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## KipperSarnie (3 Mar 2017)

Now i'm not an educated man, far from it, but Progen the original poster states he is in the tropics so the way I see it is if the air temperature is 35c & your tank is at 33c then blowing the hotter air at the water will raise the water temperature not cool it!  
I know when I worked in Singapore we used to put water bowls in front of the hurricane fans to cool the air & as far as I know the only way the water was cooled was when we topped it up.


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## ian_m (3 Mar 2017)

KipperSarnie said:


> Now i'm not an educated man, far from it, but Progen the original poster states he is in the tropics so the way I see it is if the air temperature is 35c & your tank is at 33c then blowing the hotter air at the water will raise the water temperature not cool it!
> I know when I worked in Singapore we used to put water bowls in front of the hurricane fans to cool the air & as far as I know the only way the water was cooled was when we topped it up.


Incorrect.

Blowing air over the water causes evaporation, evaporation requires energy and this energy comes from the tank water. Removing energy from the tank lowers its temperature. This is why we humans sweat to keep out body temperature at 37'C despite air temperature being once for me 46'C in Greece.

Evaporation requires energy, about 2200kJ/Kg for water. Thus evaporating 1Kg of water will require 2200kJ, which it will get mostly from the liquid water. The heat capacity of water is about 4200kJ/Kg/K. Thus roughly, evaporating 1Kg of water will lower 1Kg of water 0.5K ('C). This is how water powered air conditioners and fridges all work. They evaporate water or refrigerant, the evaporation taking energy from the surroundings, thus lowering its temperature and keeping you or your beer cool.

When camping years ago, before small fridges & site electrics became common, we used to keep fresh milk cool by placing it in a bucket of water and covering with a damp cloth (or even better an earthenware plant pot). The water evaporating kept the milk cool, just need to top up the water regularly.

In the tropics, provided the air is not saturated ie above say 70% (which of course it maybe) then blowing 35'C air over 33'C tank water, will induce evaporation thus lowering the tank temperature, no issue. You should easily be able to obtain 4-5'C drop with quite small air flows. Obviously you can get lower temperature with greater air flow but with greater loss of tank water.


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## rebel (3 Mar 2017)

Fans can achieve about 4c drop unless your tank is insulated very well. I kept water at 20C in a 5L styrofoam container with fan and continuous water top ups. Tap water was 18c and I needed to top off about 1L daily. Ambient was between 27-40.


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## Mortis (18 Mar 2017)

Unfortunately there are no cheap or easy ways to cool a tank. Im speaking from experience. Fans can cool your tank enough IF your ambient humidity is low due to evaporative cooling. The number of fans will obviously depend on the size of the tank, 4-6 120mm or 80mm should be sufficient on a four footer. If the ambient humidity is high then it might only lower the temps by a degree or two. Cross ventilation in the room will also help when using fans.
If your humidity is high like it is here in the tropics during summer then a chiller or AC is your only option I'm afraid. My tanks are in the bedroom so they get cooled to 22 by the AC which is switched on only at night and at the end of the day the max it rises to is 26 degrees.
Peltiers are only good for nanos. They need to be cooled themselves and consume a LOT more electricity on a bigger tank than an AC or chiller would.
So Progen, if your humidity is low, below 70 then you should be getting satisfactory cooling using fans, atleast 28 or lower.


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## limz_777 (21 Mar 2017)

Mortis said:


> Unfortunately there are no cheap or easy ways to cool a tank. Im speaking from experience. Fans can cool your tank enough IF your ambient humidity is low due to evaporative cooling. The number of fans will obviously depend on the size of the tank, 4-6 120mm or 80mm should be sufficient on a four footer. If the ambient humidity is high then it might only lower the temps by a degree or two. Cross ventilation in the room will also help when using fans.
> If your humidity is high like it is here in the tropics during summer then a chiller or AC is your only option I'm afraid. My tanks are in the bedroom so they get cooled to 22 by the AC which is switched on only at night and at the end of the day the max it rises to is 26 degrees.
> Peltiers are only good for nanos. They need to be cooled themselves and consume a LOT more electricity on a bigger tank than an AC or chiller would.
> So Progen, if your humidity is low, below 70 then you should be getting satisfactory cooling using fans, atleast 28 or lower.




quite true fan cooling only drop 1-2 c , always wonder how most claim it drop 4-10 c , there's another theory that number of fans doesnt matter as long as water evaporate from the tank


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## rebel (22 Mar 2017)

If you can insulate the tank and keep topping up, fans can easily do 4 degrees. My humidity is 50% though.


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## Mortis (22 Mar 2017)

They do drop the temps and keep them down even in the Tropics by 4-5 degrees but only during winter when the humidity is below 50 and ambient is 20-25 anyways


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## Progen (19 Apr 2017)

This is how I've been cooling the tank for the past few weeks. It takes the temperature 1 or 2°C down so that's good enough. Can see plants and fishes improving. The higher / ambient temperature is incorrect because that's from the sensor behind the unit. Room ambient temperature should be higher. Room fan is on all the time except for on (tropic) cold days where ambient is around 26 - 27°C.


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