DIY Chiller

[shortman]

Guys,

I was thinking of using copper pipe in the fridge but not sure it is aquarium safe.

I have the necessary power drill and hole cutter and can pass among all of us, and one tube of sealer should be enough I think.

What is the size of the bar fridge should we be getting?

Here is the last count list for the small scale chiller. Pls add yourself in with the next post. :-)

1. Gan C W
2. PohSan (budget $100)
3. A.Rashid
4. Au S L
5. Shortman

Any more people ? :wink:

Cheers

[timebomb]

Folks,

I can understand your eagerness to DIY your own chiller too but I would suggest you don't jump into the project yet. A freezer should work better than a mini bar fridge. If you start buying now, you may regret it later.

Let's discuss it a little more before deciding what we should do. Ronnie made a good observation when he said the longer the hose, the more effective the chiller will be. A freezer should be able to take a much longer hose than a bar fridge and it wouldn't cost much more, I suspect. I think Ronnie's right too when he said the pump in the tub could be an optional item. I think it actually generates more heat. It is there probably to keep the water in the tub from freezing but I wonder if a block of ice surrounding the hose is more effective than just cold water.

Kho suggested using copper but I think it will be much more expensive than using PVC. There could be some material that's more conductive than PVC but just as cheap.

I received a call today from a friend who said he found a shop that sells mini bar fridges for a very competitive price and they are brand new. They come with one year warranty but I doubt the manufacturer will honour it if we drill holes in the fridge. In any case, I prefer a freezer to a fridge so I'm keeping my options open.

Anyway, if any of you are impatient and want to embark on the project right now, I hope you will share your experiences with us. I offered to be the guinea pig but if you want to volunteer, please be my guest

Loh K L

[cheeboonyong]

Maybe we should post up a Copyright sign on the thread or just block the whole thread from being linked. That'll stop the lurkers in the tracks.

Chk this out on DIY Chiller


http://www.aloha.net/~hqf/indexdonschiller.htm 1999 design

http://www.aloha.net/~hqf/indexjrosechiller.htm 2000 design

I'm not sure if anyone has followed up on the links. The 2000 design actually is very similar to what James is doing. I'm not an expert on cooling, so it would be great if anyone can point out what is radically different between the 2 designs. Looks similar to me...

It's just incredible the amount of interest that a good picture can generate. Schematic drawings always work in theory but don't always have the persuasive power of a "live" demo. Considering the design existed since 2000 (maybe even earlier by somebody else, who knows!?!) but nobody here seems to know about it, yet when a working model is presented, everyone is all excited about it. The power of advertising...

Sorry for digressing...

[shortman]

Kwek Leong,

Yet jump into the DIY yet as I couldn't get the length of the hose/pipe right. What is the length such that it will be more efficient to transport the heat away in the water within the fridge?

I am thinking of using the filter pump to pump the water into the fridge.
The size and the temperature control in fridge is a important factor if not we have to find a way to preset the temperature in the aqurium.

It is not cost effective to auto on/off the fridge and will it shorten the lifespan of the fridge.

Thanks

[timebomb]

Sorry for digressing...

Nothing to be sorry about, Boon Yong. Actual pictures definitely will generate a lot more interest than diagrams. I'm not sure where James got his idea but it wouldn't surprise me if he found his inspiration on the world wide web. The web is such it's a wealth of information if one bothers to look. In any case, James deserves a lot of credit for putting an idea into action even if he wasn't the guy who came up with the idea in the first place.

I took a look at the 2 urls you posted and other than for some modifications, the diagrams look similar to James' setup. The diagrams don't tell what material the hose is made of though. If I saw correctly, I think they are normal rubber hoses which we know, are not very effective. There's also no mention of a thermal plate which I think is a quite important item for the chiller to work effectively.

The second diagram seems to show a picture of a freezer which as I've said before, is probably more space efficient than a bar fridge. Frankly, it's hard to get excited over a diagram as it does not convey the idea as well as a picture.

It makes me wonder sometimes why there are not more pictures on some web sites that have very good ideas. Are digital cameras in other countries less common than in Singapore?

Loh K L

[cheeboonyong]

Are digital cameras in other countries less common than in Singapore?

Guess they weren't so common back in 2000.

But you're right, a picture does indeed say a thousand words. I very much enjoyed reading your moss wall article with all the nice pictures. Show exactly step by step. Maybe video over net would be the next big thing??? But please don't film the moss growing in real time :wink:

It would be great if you guys could put a pictorial guide during your DIY setup. Those lazy people like me who wants to know better but don't want to get their hands dirty would greatly benefit from it!

[timebomb]

What is the length such that it will be more efficient to transport the heat away in the water within the fridge?

Obviously, the longer the better, Kho. The diameter of the hose is important too. Ronnie who's pretty sharp knew right away that it has to be small or else the flow will be so slow the water may freeze. We don't know which is the best length as we have to see how big is a freezer compartment before we can decide. Get the right freezer. It has to be small enough to fit into my fish cabinet or else it will stick out like a sore thumb in my living room. After we buy the freezer, we can work out how long the hose should be. Freezers are not usually used in households so they are not sold as commonly as bar fridges. But if we look hard enough, I'm sure someone will find a shop that sells a freezer of the right size.

I am thinking of using the filter pump to pump the water into the fridge. The size and the temperature control in fridge is a important factor if not we have to find a way to preset the temperature in the aqurium.

How the temperature is preset will depend on how cool you want your tank to be, I think. We all would love to see condensation but it can be quite a chore if we have to clean the glass every day. As for pumping the water into the fridge, I think it's the other way round. Water will flow into the fridge through gravity and the filter will pump it up back into the tank.

It is not cost effective to auto on/off the fridge and will it shorten the lifespan of the fridge.

Definitely. But I don't think we will have to on off the fridge all the time once we know what's the best reading on the thermostat to set it on. We probably have to monitor it closely at first and find out for ourselves what's the best reading. Everyone's tank is different. Size, water circulation, room ambient temperature - these factors will affect the effectiveness of the chiller.

Loh K L

[timebomb]

Those lazy people like me who wants to know better but don't want to get their hands dirty would greatly benefit from it!

I'm glad you like my moss wall article, Boon Yong. It was my very first article and I was quite surprised to find out recently that it has been translated into Hungarian on some other web site. Whaddaya know?

I'm all tied up with a course this week so I can't spring into action until this Saturday. Melvyn, my good friend called just now and he's keen to work on the project too. We will probably go shopping for a freezer this weekend. When I get all the parts, I will post the addresses where you can find them. I will also take step by step pictures when Melvyn rigs up the whole thing.

It's for lazy bums like you that people like me exist, Boon Yong .

Loh K L

[Green Baron]

Folks,
I can understand your eagerness to DIY your own chiller too but I would suggest you don't jump into the project yet. A freezer should work better than a mini bar fridge. If you start buying now, you may regret it later
....

Anyway, if any of you are impatient and want to embark on the project right now, I hope you will share your experiences with us. I offered to be the guinea pig but if you want to volunteer, please be my guest

Loh K L

Kwek Leong,
Agree with you that we should not jump the gun. As pointed by Kho and Ronnie, there are still rooms for improvement and since you have very kindly volunteered to be the guinea pig, we should wait and learn from your experience. In fact we could all share the cost of this 2nd prototype so that you don't have to bear it all for our benefit !

If I am in in town this weekend, I will drop by your place to see how the thing is setup. I think we can wait another week or two ;-)

What are important to me are size and aesthetics as the chiller will be sitting in my living room. Do you think the chiller can be placed inside the cabinet under the tank ?

[timebomb]

Do you think the chiller can be placed inside the cabinet under the tank ?

I'm not sure about that, Gan. There are some chillers that are pretty small but almost all open at the top. The freezer may fit into the cabinet but there may not be enough space to open it.

Besides putting it inside the cabinet, I have another option, which is to position it in my balcony which is just behind my main tank. I'm reluctant to do that though because the balcony is exposed to weather conditions. If it rains heavily, my balcony gets all wet. On normal days, it gets very hot.

Loh K L

[timebomb]

In fact we could all share the cost of this 2nd prototype so that you don't have to bear it all for our benefit !

Thanks for the offer, Gan but there's no need to do that. I don't mind being the guinea pig as the cost isn't very high. I was told this evening that there's a shop that sells mini-bar fridges for less than a hundred dollars each. And they are not second-hand. Can't confirm it though as I've yet to visit the shop myself.

If I am in in town this weekend, I will drop by your place to see how the thing is setup. I think we can wait another week or two ;-)

You're always welcomed to visit me but I don't know if there's enough time to rig the whole thing up. I forgot I have to be at Eco-Culture this Saturday evening.

Loh K L

[turaco]

Just my observation, wonder how long can the bar fridge last(life span) ? It's like running a fridge with it's door open, the fridge will work very hard in order to reach its desire temperature. In normal closed door fridge, the thermostat will cut off once it reaches the coldness, thus the fridge get to 'rest'. But in the case of this experiment, it seems like it's going to run non stop till it get burnt out? Maybe a higher power fridge will solve the problem?

[timebomb]

JBut in the case of this experiment, it seems like it's going to run non stop till it get burnt out?

I'm not sure, Gan but I think it won't work the way you described. It will probably use up a lot of energy in the beginning but once the tank is cooled, only a litle energy is needed to keep it at that temperature. The door's always closed and there's no reason to open it unless to check the equipment. Opening and closing the door will cause the fridge to use more energy, of course.

Loh K L

[turaco]

The door's always closed and there's no reason to open it unless to check the equipment.

What I mean is, there's an external source of heat(tank's water) that is constantly entering the fridge, stressing the mini fridge, which is what it is not designed for. While the tank may be cooled eventually, the low-powered bar fridge had already worked double hard. That is why I'm asking about it's durabilty.

[whuntley]

Placing the chiller under the cabinet will defeat the purpose unless the cabinet is very well ventilated to the room. The hot case will add as much heat back as is being extracted or even more. The objective is to pump heat out of the tank and put it elsewhere.

Copper tubing has high conductivity but could be dangerous to the inhabitants of the tank. If a pH "crash" happens, the copper can be dissolved (ionized) and enter the water. Bye-bye inverts, and maybe fish, to heavy metal poisoning. Even worse if solder filtting are used instead of compression fittings. [I once killed a tank of FIL because I left the lead anchors on some plants from the store and the pH was quite low. Ugly scene! ]

Aluminum tubing is probably safer, as the inside surface forms a solid layer of aluminum oxide (sapphire) that sort of keeps it inert. I have never heard of a (convincing) toxic problem with aluminum in aquaria. Never used this much in water contact, though.

As far as patents go, reef folks and stores have used refrigerators in place of chillers for over 50 years, so any patent on that idea is long expired or invalidated by "prior art."

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.]

Use an aluminum pot to hold the coil. The heat transfer from air to water will be greatly improved over any plastic tub or bucket. Even a galvanized bucket or wash-tub would be OK, as the zinc doesn't contact tank water at any point. Stainless steel has lower conductivity, so think twice about using it, even if it will last longer. The metal container will increase temp. gradients and stop the need for an inside pump, probably, by convection stirring. Even an old glass aquarium with thin walls might be a little better than the poly pan shown in one photo (not sure about that, though).

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.

Wright

[timebomb]

While the tank may be cooled eventually, the low-powered bar fridge had already worked double hard. That is why I'm asking about it's durabilty.

We won't know the answer to that question until we have used it for a while, Gan. The fridge may go kaput after a while but that's a risk we have to live with if we go DIY. You can be patient and wait several months or a year or 2 to see how things work out but I doubt anyone's that patient . As it is, I'm having a hard time asking everyone to rein in their horses .

Loh K L

[RonWill]

...who's pretty sharp knew right away that it has to be small or else the flow will be so slow the water may freeze. We don't know which is the best length...

One small correction. Kwek Leong, he purpose of a smaller diameter hose is for it's flexibility and also the fact that you can pack a longer length of hose within a limited space. The longer the path taken, the better the freezer/fridge is able to cool the travelling water till it leaves the 'chiller'. I would hazard a guess that there'll be no chance for the tub of water to freeze over as the incoming water will be constantly 'defrosting' it with a constant flow rate.

The best length is, of course, the longer the better.

Just my observation, wonder how long can the bar fridge last(life span) ? It's like running a fridge with it's door open, the fridge will work very hard in order to reach its desire temperature. In normal closed door fridge, the thermostat will cut off once it reaches the coldness, thus the fridge get to 'rest'. But in the case of this experiment, it seems like it's going to run non stop till it get burnt out? Maybe a higher power fridge will solve the problem?

Gan, if you can see the thermostat plate under the coil of hose, the water in the container is set by the dial. Once the preset is reached, the compressor doesn't kick in until it's needed.

The fact that the water-filled container has considerably reduced the internal space, the freezer actually don't have to work very hard. Much lesser than the home fridge where the kids keeps opening it for snacks! In that regards, an half-filled fridge will take longer to cool down again when compared with a stuffed-up fridge. A distant analogy might be using a high BTU air-conditioner to cool a small room against a lower rated unit to cool a large room.

If you look at better designed whiteware (another nice words for kitchen appliance like washers, dryers, fridge, etc), there are vertical standup front-access freezer (yes, only freezer) that has drawers. The drawer retains as much of the cold air while the door is opened. Think back to the chiller design. The main bulk of the available space is already taken up and since the water (in the container) is already quite cold, plus the fact that it's rarely opened, the 'cold-loss' is quite negligible.

Anyone doubting that this will work can try something I've tried, albeit some years ago.

• Get the largest polyfoam box you can find (either from fishing supply stores or your wet market).

• Cut out 2 access holes for the water inlet & outlet from the canister filter.

• Coil up some smaller diameter rubber hose to fill up the bottom half of the box.

• Cover the hose with crushed ice and fit 2~3 solid blocks of ice over it.

• Run your filter as per normal.

... then get back to me with the details (how long the ice last and how low a tank temp you're able to achieve). Upfront, I'll tell you that if the temperature doesn't drop to 22ºC, you're doing it wrong :wink:

BTW, did I tell you that I'm a very curious animal?

[timebomb]

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.

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.

As far as patents go, reef folks and stores have used refrigerators in place of chillers for over 50 years, so any patent on that idea is long expired or invalidated by "prior art."

Patenting the idea was never a consideration, Wright. Nothing new was invented anyway. It's just assembling equipment used for other purposes.

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?

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?

Loh K L

[timebomb]

... then get back to me with the details (how long the ice last and how low a tank temp you're able to achieve). Upfront, I'll tell you that if the temperature doesn't drop to 22ºC, you're doing it wrong :wink:

I tried what you suggested years ago, Ronnie and it didn't work. I didn't immersed the hoses into iced water though. I had my 2 external cannister filters buried up to their necks in ice in a styrofoam box and after all the ice had melted, the temperature in my 4 feet tank didn't even drop by half a degree. Plastic cannister filters are not great conductors of heat, that's what I gathered.

Loh K L

[RonWill]

Plastic cannister filters are not great conductors of heat, that's what I gathered

I recently replaced an impeller rod (satay stick) for the real ceramic rod and the accompanying rubber bushings. Tested the Eheim 1060 in a small blue pail and let it running, water being re-circulated at a fast rate.

About half an hour later, the water was warm to the touch and the thermometer read 41ºC

By having the 2 pump motors within the same confine simply means that what cooling the ice achieved is negated by the heat displaced... kinda like running a heater and air conditioner on at the same time in the same room. That's why you don't see the main pump in the fridge. Makes sense? (alternatively, it's like having the AC compressor inside the room you're trying to cool)

Further more, the path of water within the canister is nothing compared to coiled tubings. It is the prolonged intimate exposure to the cold that we want to achieve. I should have mentioned that smaller diameter rubber hoses usually have thinner walls and easier to to coil up instead of larger thicker ones.

The earlier mentioned 22ºC was observed in my 4footer as well, considering I had 2 x 150w MH lights going. I gave up only because I've gotten tired of refilling the ice.