DIY Chiller

[whuntley]

Placing the chiller under the cabinet will defeat the purpose unless the cabinet is very well ventilated to the room.

Wright, wouldn't it be great if the cabinet below the tank heats up? Wouldn't it be something like undergravel heating cables? Very few hobbyists here use heating cables as our tanks are never cold enough to make a difference. But I wonder now whether it's worth doing it.

No it isn't the slightest like cables. They cause little convection currents because they are local hot spots with nearby adjacent cool areas. Uniforn under-tank heating does nothing to cause that intra-substrate circulation.

What is more, no one uses cables any more after Tom Barr showed how useless they really are. A few die-hards like Geo. Booth, maybe, but mostly they are in tanks much too hard to tear down and fix.

Aluminum tubing is probably safer, as the inside surface forms a solid layer of aluminum oxide (sapphire) that sort of keeps it inert.

Aluminium tubing? Hmm, that's a new one for me. I don't know where we can get such tubings in Singapore. It could possibly raise the price of the chiller by quite a fair bit. The PVC hose James is using now costs only Sing $1 for a feet.

I don't think aluminum tubing is much more expensive than that. It has nearly replaced copper in many dehumidifiers and AC units. I would not be inclined to use any vinyl hose because the plasticizers in it are harmful over the long haul. Note that hospitals have banned "Tygon" and similar tubing for any patient contact stuff. Stick with polyethylene without any plasticizers.

From a cost standpoint, polyethylene tubing, like that white frosty stuff used for refrigerator ice-makers, is the most practical, but it doesn't have the conductivity of metal. Use as large a diameter and thin wall as can be coiled in your bucket or tub to essentially fill it. Fill with salt (or sand) and wrap around a dowel or pipe before dunking in boiling water if you want tighter coils. [Salt is more expensive but easier to remove. It washes out.]

That's a great tip, Wright. I will surely try using salt to coil it when I get my hands on the PVC tubing. But I don't understand what you meant by large diameter? Wouldn't that slow the flow of water? Hmm, I think I got you now. Slowing the flow will keep the water in contact with the cold water in the tub longer, thereby lowering the temperature further. Is that right?

You don't need anything for clear polyvinylchloride tubing as the plasticizers make it pretty limp. The frosty polyethylene is fairly stiff and resists really tight bends without a bit of heat inducement.

Larger diameter means more total water flow (GPH) and less back pressure on the pump. If you use the 1/4" refrigerator ice-maker tubing, there will be too little volume and danger of freezing, IMHO.

Use an aluminum pot to hold the coil.

That's a great idea. Metal conducts heat much better than plastic. Getting a aluminum pot should be much easier than the tubings.

Ice is a fairly good heat-transfer insulator, so I don't think you want any in the tub at any time. It also will block convection currents.

Got that, Wright. But wouldn't the water freeze if there's no powerhead to keep the water moving?

Not if you have enough tank water flowing through to keep it from happening. Setting flow volume and the refrigerator's thermostat will be a part of the initial fine tuning. Increase flow or reduce thermostat to avoid any icing up.

Wright

[victri]

To avoid freezing of water in the tub, maybe can consider automotive antifreeze coolent. They have very low freezing points, and I've used them in my car in temps of -40deg C (when I lived in Canada). There'll be a danger of poisoning if any of that leaks into the tank though. You'll need to totally seal off the hose and tub to be safe.

I'm curious as to how the overall flowrate might be affected, and how that in turn might affect the CO2 dissolve rate for those running in-line CO2 reactors.

[FC]

KL and Gan,
As Wright explained, fridge (or air-con) provides cooling by extracting heat from the target zone (a compartment or room). As such, the efficiency of the fridge depends very much on how this heat (you felt when you touch the back of the fridge) is facilitated to be put away.
Therefore, an enclosed cabinet would not be a feasible location for the fridge where air circulation is bad. Unless, of course, you place a matching sized exhaust fan on the cabinet.

Wright, Ronnie and experts,
I have an idea which I need your comments. In place of the piping, the tub, etc, can I use a small radiator with fan like those used by small motorcycle? It is fully made with aluminium.
I will then place a thermostat that measures the tank’s water temperature. This thermostat will in turn control the radiator’s fan (on/off), the fan’s suction side facing the evaporator. With these, I hope to achieve:
1) high efficiency of heat transfer
2) simple and accurate tank’s water temperature control scheme
3) more space for other usage
Kindly advise if this would work.

[whuntley]

Yes, it should work, but you are adding the fan's heat to the water. I think the liquid bath is better. Can you submerge the radiator?

I'd probably use a separate water pump and have it turned on and off by the thermostat, too.

Wright

[stormhawk]

JianYang, Ronnie and Freddy should I count you in?

Kho, I'd be glad to land a helping hand. Didn't notice this post of yours till tonight. Pardon the blurness Anyways, tell me when you need some help, with hands that is, and I'll drop by. Money-wise, I don't think I have enough to invest in a small bar-fridge, besides, my dad will kill me if I add another bulky item to the already messy tank area.

[shortman]

Once we have pick the right fridge, next was to strip the fridge to see if it is possible to add an additional temperature controller into the fridge.

The ideal is to control the tank water temperature and reduce the running cost. Parts can be easily get from the electronic/electrical store in town.

But we will wait for what Kwek Leong has come up with the DIY prototype.

Use of aluminum pipe in the fridge is a good ideal in this case we may not need the water tub and aviod the it being ice'ed. Running water in the pipe will not cause the water in the pipe to freeze.

Cheers

[shortman]

Since we are on this topics and for the interest of the community here,
check this url DIY: Ultimate Ghetto Chiller
http://www.saltwaterfish.com/vb/show...ht=%2Afridg%2A

Best Regards

[Green Baron]

Since we are on this topics and for the interest of the community here,
check this url DIY: Ultimate Ghetto Chiller
http://www.saltwaterfish.com/vb/show...ht=%2Afridg%2A

Best Regards

A picture from the above mentioned post

[shortman]

Gan,

Did see beer ?

Cheers

[timebomb]

Hi, fellas,

I went looking around for a freezer yesterday and the best one I found was at Carrefour's. They have a freezer that is 106 litres going for $269. The freezer is a bit too large for my liking so I'm going to shop around some more tomorrow. I have the contact for a shop that specialises in freezers but they aren't open today.

Anyway, here's the plan:



With 106 litres, I think I can coil maybe 30 feet of PVC hose . It's a bit overkill, I know but I don't do things in small measure . The freezer will be behind my tank in my balcony where it's hidden from view.

I don't intend to put in a plastic tub or an aluminium container to hold the hose as the compartment of the freezer is one big opening. I will just fill it up with water and submerge the hose inside. As for using a powerhead to prevent the water from freezing, someone said if I'm concerned with that, I can simply use an airline connected to an air pump to aerate the water. It should work just as well as a powerhead, he said. I wonder if that's correct?

I wonder too where I should drill the 2 holes. Would it make any difference if they are on the same level or would it be better if the inlet is higher than the outlet? Or vice versa? I don't want the holes to be on top as the freezer's cover is there. The diagram shows the 2 holes near the top of the freezer. Would it be better if they are lower?

Wright, I checked out the polyethylene tubing you recommended and I find them to be too stiff. They are also thicker in diameter and more expensive. So I think I will use PVC.

The wattage for the freezer is 118 watts. According to Freddy, multipying the wattage by 0.12 would give the electric costs a month. So that would be something like $14.16 per month. That would be if the freezer runs non-stop 24 hours a day but I expect the bill to be lower as there's a thermostat to control the temperature. Anyway, $14.16 is just slightly more than what I spend on cigarettes everyday so it isn't a big deal to me. If I want to save, I should give up the damn weed instead.

Comments, anyone? Do you think my 380 litre tank will turn into a block of ice if I set the thermostat at it's coldest reading?

By the way, guys, I looked at many mini bar fridges yesterday but didn't see a single one I liked. Unlike the one in the picture Gan posted, the compartments inside bar fridges I saw are always divided into 2. Most times, the lower one is smaller as the compressor located at the back of the fridge takes up some space. It would be difficult to coil a long length of hose inside a bar fridge but if your's is a small tank, then maybe it wouldn't make any difference. But I still think it's a waste of space even if you use the lower compartment to store beer.

Loh K L

[shortman]

Comments, anyone? Do you think my 380 litre tank will turn into a block of ice if I set the thermostat at it's coldest reading?

Kwek Leong,

Yes, given the right condition and time it will turn into block of ice as I saw it in the wet market.

The closer I can find is this one in ebay.com.sg LG make.


Best Regards

[timebomb]

Hi, fellas,

I went to 2 different places to look at freezers today but didn't see any that was smaller than the one in Carrefour's. Melvyn was with me today and in our discussions, we came to the conclusion that a bar fridge won't work well for a big tank. Chances are, in the case of a bar fridge which has much smaller space to hold the coiled hose, the compressor will have to run non-stop and therefore, willl burnt itself out very fast. As I've said, the side of the bar fridge James is using was hot to the touch. So hot, it will roast your fingers if you leave them there.

My wife runs a provision store so I'm asking her for help. There's a brand of ice-cream in Singapore called Potong and they are sold in freezers that are of the right size. The problem with getting this freezer is that it isn't for sale. The company that markets Potong imports this freezer for their own use only. I'm keeping my fingers crossed that my wife can persuade them to sell one to me.

Loh K L

[ReDDeviLs]

Hi guys, happen to saw this thread here..
i have a 600L tank and i'm very interested in this cooling system idea.
infact im running a marine tank and i need to cool the tank else my corals will die from the heat.
I have been searching for a chiller that can support my tank but the price are way too expensive ranging from $800-$2000
wonder if this DIY project can work.
If this project can work i would be very very interested

[FC]

As I've said, the side of the bar fridge James is using was hot to the touch

Fridge, like most cooling equipment, removes heat away from the target zone. The heat you expereinced showed that the fridge is pumping the heat out and deposit it on the casing. It is normal and should be hot at the pressurised part of the system.
For your information, anything that is too hot to touch is above 50~60 degree celius.

[Kenji80]

Yesterday I saw 1 freezer at Suntec Courts and the cost is around $250.

Brand is Akira and Dimesion is 60 depth * 37 width * 84 Height cm.

[timebomb]

Okay, fellas,

I'm in touch with the guys from Potong ice-cream. We spoke on the phone and he said their freezers are of size about 1 ft X 2 ft X 3 ft. That would be 30 cm X 61 cm X 91 cm. A new one, he said, costs in the region of Sing $500 but a second-hand one can be had for $100 over dollars. He couldn't be specific on the phone so I can't confirm the details.

I'll be visiting their factory tomorrow to take a look. I wonder if any of you are interested. The Potong ice-cream freezers, as far as I know, are not for sale anywhere. All I've seen so far are too big for my liking. With a freezer, there's efficient use of space as it has only one compartment when compared to a bar fridge which comes with 2 compartments.

Freddy, I know there's heat transfer but if the compressor is shut off by the thermostat now and then, I believe the side won't be that hot. Am I right? An overworked fridge will burnt itself out very fast. Would that be correct?

Loh K L

[FC]

An overworked fridge will burnt itself out very fast. Would that be correct?

Most probably.
One way to go around it is the use of timer. Setting example: round the 24 hr timer, turn off the fridge for 15 minutes (=the single click) every hour.
With some trial and error, we can even control the water temperature by timer. Very much like the way we control the CO2. Example:
During the day: turn off for 15 minutes every hour
During the night: turn off 15 minutes every 45 minutes

[timebomb]

Thanks for the tip, Freddy.

I have another question. The side of the bar fridge James is using is where the coils are located. He drilled the 2 holes on the cover but I don't intend to do that when I get my freezer. My 2 holes will be on one side of the freezer. I asked several times but the people who sells freezers don't know where the coils are located. I'm kind of worried that when I drill, I will hit and puncture the coils which could be on one side or possibly, both sides of the freezer.

What do you think?

Loh K L

[stormhawk]

KL, if the Potong freezer is the one made with sliding plastic/glass covers then you can just drill through the cover instead of drilling somewhere where you may puncture the coil. The Potong freezer however has one drawback. Its quite thin in width but the height of the freezer may play a major role if one wants to incorporate this into his tank stand/cabinet. I did see a very small mini-bar fridge for sale recently and it was highly suitable for this purpose since it was small enough to squeeze into a cabinet/stand.

Found another purpose for the fridge apart from the chilling factor and ideas like a beer fridge. It seems that since some of us do utilise frozen foods for our fishes and almost everyone has a can or a canister of BBS eggs lying around, the fridge can become a place to consolidate all these items. Saves up valuable fridge space in the home fridge and certainly prevents our resident MHA (in my case my Mom for now) from complaining about frozen worms and cans of eggs in the fridge. :wink:

[FC]

KL,

You can trace/find out the coil location by first running the fridge for about 5 minutes (not too long). Touch the whole body (ahm, I mean the fridge ) with 2 fingers. Of course, you knew where it is warm, there is coil.