DIY Nano Chiller using a 6L esky.

[OzHobbyReefer]

Hi Guys,

 

I'm fairly new to the saltwater hobby but thought I'd dive strait in and start a nano tank. Due to my location (central Queensland coast in Australia) I also required a chiller as it gets very hot and humid here.

 

After doing plenty of research and reading there didn't seem to be any viable options for nano chillers at a "reasonable" price. Being a DIY kinda guy I thought why not take a shot at building one using everyone else's experience. I may even get lucky and make something that works better for my needs then something off the shelf, although it wouldn't look as fancy.

 

I always had the mind set during this build that it may not work and if it didn't no worries, I'd make up a plane 'B'.

 

This is a closed loop system just like a production chiller, the aquarium water is plumbed into a coiled 12mm hose within the esky and then back out into the aquarium. The esky is filled with clean water which is cooled by the peltier unit and in turn cools the aquarium water getting pumped through it. The water temp in the esky should stay quite stable due to the insulation meaning the chiller shouldn't have to cycle on/off very quickly which will be less wear and tear on the peltier unit.

 

All up this build cost a little over $100 AUD mainly because I bought a new esky (very pricey) and a good quality CPU cooler.

 

 

Any way enough gas bagging, here is the chiller. Feel free to ask any questions and I'll keep you updated as to how it performs.

 

 

This is the Chilling unit made from a CPU cooler, 65w Peltier unit and a copper heatsink on the cold side. The power supply is a 240v to 12v 6amp ebay job.

1.

 

These next photos show the chiller unit mounted on a 6L esky with fittings for the hoses.

 

 

As you can see the copper heat sink sits under the lid and is submerged in the water.

 

This is testing that the chiller actually does cool the water and that there are no leaks. The esky is filled up with RO/DI water.

 

This is the chiller plumbed into the aquarium. It currently works well and is keeping the 20L of aquarium water close to 26 degrees celsius. The position of the chiller actually allows air from the fans to pass over the LED light and tank to further help reduce temps.

 

I have the chiller powered by my temp controller. The temp controller is set to maintain 26 degrees celsius, the chiller kicks in at 26.3 and the heater kicks in at 25.5.

 

This chiller is currently working really well, when the chiller kicks in there is sometimes another rise of 0.1 or 0.2 degrees before the water temp starts to drop. It will then take around 2hrs to gradually cool the water down to 26. Once there the cool insulated water in the esky helps to maintain a stable aquarium temp for quite a few hours before it reaches 26.3 again and the chiller kicks back in.

 

 

We haven't had any super hot days yet so I am keen to see how this holds up over the Christmas holidays but so far so good.

[sam_the_reefer]

But, copper is deadly to inverts.

[evilc66]

Pay attention. The tank water is never in direct contact with the chiller system. The tank water is circulated through numerous turns of tubing that is submerged in the cooler that contains the chilled water. It's not the most efficient setup, but it is fairly cost effective. Changing to a semi-rigid, thin wall PEX or polyethylene tubing would help increase the efficiency a little, as it will have less of an insulating property than pvc or vinyl does.

[blizzardscout2]

Wow! Nicely done, I bet that thing will come in handy at times.

[evilc66]

Another thought would be to add a pump in the cooler to circulate the water. It will get the "coolant" temperatures down faster, and keep them more consistent around the tubing.

[OzHobbyReefer]

Pay attention. The tank water is never in direct contact with the chiller system. The tank water is circulated through numerous turns of tubing that is submerged in the cooler that contains the chilled water. It's not the most efficient setup, but it is fairly cost effective. Changing to a semi-rigid, thin wall PEX or polyethylene tubing would help increase the efficiency a little, as it will have less of an insulating property than pvc or vinyl does.

 

Thanks evil. Yeah I agree vinyl isn't very efficient but I had it lying around. Also I only used 3m and could probably fit around 5m in which would help even more. I may experiment with different materials down the track. I think what helps in this system is the fact that the tubing is submerged the whole time and at this stage rarely gets above 26.5 degrees. There isn't much temperature transfer that actually needs to happen to cool the water back down. The water flow through the 12mm hose is slowed down after coming in through 8mm hose from the tank and it takes about 9sec to pass through the chiller. I think this also helps cool the aquarium water better.

 

Wow! Nicely done, I bet that thing will come in handy at times.

 

Cheers blizzardscout. I will be very handy....if it continues to perform

 

Another thought would be to add a pump in the cooler to circulate the water. It will get the "coolant" temperatures down faster, and keep them more consistent around the tubing.

 

Not a bad idea. There isn't a lot of room left in the esky though so could be a bit tight even for a tiny 300lph pump. It would need some testing as well to see if the extra power draw of another pump would out weigh any reduction in running time for the peltier.

 

 

I have thought about building a double walled insulated acrylic box to replace the esky. I could then build it to a size of my choosing and it would look a hell of a lot nicer.

But, copper is deadly to inverts.

That is very correct. The only viable metal that can ever come into contact with aquarium saltwater (especially in the long term) is Titanium.

[evilc66]

It really wouldn't take much flow at all to improve things. You could get one of those cheap Chinese 12v DC fountain pumps. Power consumption on them is really low, and they are generally tiny. I would think there is enough room in the middle of the coil to fit something, and if you get a 12v DC unit, it could be powered from the same supply as the heatsink fan.

 

http://www.aliexpress.com/item/12V-Mini-DC-Pump-3M-4-2W-Plastic-Aquarium-Pump-Submersible-240L-H-Super-long-life/580455097.html?spm=2114.01010208.3.11.2sxotX&ws_ab_test=searchweb201556_7,searchweb201602_4_10057_10056_10055_10049_10059_10058_10017_405_404_10040_10060_10061_412,searchweb201603_1&btsid=cbea6edc-2732-4180-a50f-0fcf95f98786

[OzHobbyReefer]

It really wouldn't take much flow at all to improve things. You could get one of those cheap Chinese 12v DC fountain pumps. Power consumption on them is really low, and they are generally tiny. I would think there is enough room in the middle of the coil to fit something, and if you get a 12v DC unit, it could be powered from the same supply as the heatsink fan.

 

 

 

I do have a spare little 300lph pump very similar in size to that. I might try this idea if I find the chiller struggling in the hotter months and see how it performs.

 

We've been having a bit of a cold spell so the chiller hasn't had a chance to run in the past few days but it will be warming up soon enough.

[Hanzel]

Nice work but second hand chillers are cheap! Under $150 and much more reliable.

But again, nice work.

[BulkRate]

Really impressive DIY. One advantage of this unit is that every part on it is user-serviceable. I HATE relying on any component in my tank that can't be gotten locally and at most normal hours any day of the week.

 

Nothing worse than that sinking feeling when something quits on you and now you're in a race against the clock to keep things alive.

[OzHobbyReefer]

Nice work but second hand chillers are cheap! Under $150 and much more reliable.

But again, nice work.

 

Thanks Hanzel. I have seen some second hand ones online but very hard to get a hold of where I live. Expensive to post as well.

 

Really impressive DIY. One advantage of this unit is that every part on it is user-serviceable. I HATE relying on any component in my tank that can't be gotten locally and at most normal hours any day of the week.

 

Nothing worse than that sinking feeling when something quits on you and now you're in a race against the clock to keep things alive.

 

Cheers BulkRate. Yes I agree and I love being able to service everything easily. The only thing that should need replacing on this chiller is the peltier unit. And that costs about $10 AUD and takes about 5 mins which means I can get it back up and running before my tank even knows what happened.

[William]

you may want to add some food coloring to the chiller water to ensure you are not having any mixing (highly unlikely) but better to be safe than sorry.

[OzHobbyReefer]

you may want to add some food coloring to the chiller water to ensure you are not having any mixing (highly unlikely) but better to be safe than sorry.

 

Hey that's a good idea, assuming food colouring doesn't hurt saltwater aquariums as it would quickly dilute if there was a leak. I have sealed up the connections with silicon and kept a close eye on the water level in the esky and the fittings don't appear to be leaking. They are actually slightly above the water line due to the inside of the lid being sunken in so you would most likely see air bubbles being sucked in if there was a break in the connection.

[dorky08]

Wow this is a neat idea! I like it n want to see the results later

[OzHobbyReefer]

Well it's hard to post any real update as we still haven't had any hot days. There has been 1 or 2 warmer days where the inside room temp reached 26 which would have put the tank temp at around 27.5 as it sits about 1.5 degrees above ambient but the chiller easily kicked in at 26.3 and cooled it down to 26.

 

Updated pic with a piece of rock removed from the top to open up the tank more.

 

This is the temp controller sitting below the tank with the ATO in shot.

[RollaJase]

Very nice DIY, I'm glad its working out for you.

[OzHobbyReefer]

Quick update on how the chiller has been performing lately.

 

We have had a couple of warmer days now. The inside ambient air temp has reached 28 degrees C on multiple occasions. My chiller has been kicking in at 26.3 and the highest that the water temp reached was 26.8. After about 2-3 hours the water temp chilled back down to 26.

 

The chiller doesn't have a lot of cooling power initially and it took a couple of hours before it stabalised and bought the water temp back down but so far I'd say it was a success as there was only a 0.8 degree fluctuation in water temp.

 

I'm interested to see how it goes with an inside ambient air temp of 30, although that would be rare as we should have the A/C running during the hotter months (unless we aren't home).

[evilc66]

Sounds like success so far.

[Hanzel]

Silly question perhaps but you seem to know a lot about cooling computers.

 

Is it better to pull air through the fins of thew heat sink OR push air through them

[OzHobbyReefer]

Silly question perhaps but you seem to know a lot about cooling computers.

 

Is it better to pull air through the fins of thew heat sink OR push air through them

 

Haha sorry to disappoint but I'm not sure on that one, my computer is water cooled.

 

I think pushing would be the primary method you would go for as that way the fan is pulling in unrestricted air and pushing it through the fins.

 

If your fan is trying to pull air through the fins then I can't imagine the volume of air flow being as much due to the restrictive nature of trying to draw air through something (heat sink fins in this case). A cars radiator is an exception as you have ram air while driving.

 

This is purely my opinion as I'm no expert.

[RollaJase]

Silly question perhaps but you seem to know a lot about cooling computers.

 

Is it better to pull air through the fins of thew heat sink OR push air through them

That is an age old question when it comes to PC cooling. Ultimately, with current technology both options are very similar is terms of performance. Personally, I prefer to push air through a cooler or radiator but sometimes you don't have the space so may have to set it up in a pull config. It also depends what you are trying to cool as fans designed for heatsinks aren't necessarily good for radiators. Most coolers can be set up to have a fan on each side for a push/pull config, this tends to work best with staving off heat soak and maybe saving a degree or two based on cooler design.

[evilc66]

Push. You take advantage of the air pressure created by the fan blowing the air out creating higher velocities, and making cooling more effective. It's also more directional, meaning you put the air where you want it. When you pull air through a heatsink, you have a much larger area to draw air from, and your overall velocity is lower for the same amount of airflow. You also don't control where that airflow is coming from, so you don't get even distribution of airflow across the heatsink (unless the heatsink is in a plenum).

[OzHobbyReefer]

I have now moved to a new nano tank, an IM Nuvo Fusion 10, and have set the chiller up on that. So far it's working better as the total water volume of the system has dropped off about 10L, the Fusion 10 has about 25L total water volume now.

 

I tested the water temperature inside the esky after the cooler had ran for about an hour and it was 24 degrees C. The chiller has no problem keeping the aquarium water down at 26 degrees C with an inside ambient temp of up to 29 degrees C.

 

The other day it reached 30 degrees C inside the house and the aquarium water reached 26.5 for a period in the afternoon.

 

I may experiment with using a different tube coiled inside the esky to try and get better thermal transfer which will make it so much more efficient at cooling the aquarium water.

[nanoreeFan]

Any updates or mods to your cooler? thanks