DIY Chiller

**green plant** · 16th Mar 2008, 20:23

After reading all the post and advise from Wright, start proto type testing today.

Configuration:-
1. Tubing 22 mm OD x 1 feet length x 2 pieces
* Yes 1 feet length. No extra tubing
2. Total Volume of water : 19 ltr (plactic bucket + resservoir (chiller) + Canister)
3. Thermostart setting 4.
4. Cooler was placed next to plastic bucket

Flow of water

1. 2 x 22mm OD tubing shiphorn to Chiller Reservoir.
2. Canister filter pump water from reservoir then output to tank.

After 2 hours

1. Temperature in the tank : 22.3
2. Temperature in the reservoir : 22.3
3. Temperature of the cooling coil/ fin : 48 deg C (maximum)

Will buy some tubing and try full testing in 2x3x3 ft tank coming Saturday.

After 2 hours change Setting to 2. One hour later drop to 20.1 deg C.

Koh Heng

**green plant** · 24th Mar 2008, 00:01

Hook up the system to a 3ft tank.

Water : 230 liters
Before switch on : 28.5 deg
6 hours later, it only drop by 1 deg.
When stop the filter, chiller reservoir water went down to 16 deg within 20 minutes.

So sad can not get 25 deg.

Will try to use fan and chiller system to try again. Will put on a timer in the cycle of rest for one hour for every 6 hours switch on.

**mozaqua** · 26th Oct 2008, 22:33

Just my two cents on your DIY chiller.

Great idea, I thought about doing something like that myself, but I don't have the time or space. Anyway, I think you could greatly increase the efficiency by changing the hose inside the refrigerator to a conductive metal pipe like copper or aluminum, although a non-corrosive/non-toxic metal like titanium would be best. I think if you want cheap and efficient go with the copper pipe used for household plumbing. This should be non-toxic, and not leach copper into your water (which is bad for plants and inverts).
If you use a copper coiled pipe, no need to put it in the water. Just attach it to the back or shelf of your freezer, and have the water continuously flowing to prevent it from freezing. I think the temperature regulation would be much easier using the metal tubing vs. plastic. If you want it to be very accurate you could connect the thermostat to a temperature probe inside your tank, that way the fridge will kick on when the tank is too warm. A great thing about many household appliances, the schematics are readily available(sometimes inside the unit).

Regards,

**timebomb** · 27th Oct 2008, 10:22

Mosiah,

I've already tried copper tubing. It causes problems. It becomes toxic and has disastrous effects on the fish and plants. Take a look at pages 15 and 16 of this thread.

Loh K L

**mozaqua** · 28th Oct 2008, 04:53

Loh,

I just read your previous thread. I suspected that sort of thing would happen with regular copper tube. The kind I am talking about is coated on the inside with a thin plastic, epoxy, or even Teflon. The coating is very thin compared to your thick rubber hose, which will allow the heat transfer to the coil, where you want it. I am not sure if you can find it in Singapore or not, you may have to order it through a catalog or online. I did a quick google search but I am not sure what it is called, I have seen it in plumbing stores in the US though.
I think if you could find epoxy coated tube, it would be best for the water quality and for long term use. Teflon has good heat transfer properties, but it flakes easily, may only last a couple years before it wears off. Also Teflon coating is usually custom made, or expensive. If your only running fresh water, aluminum is cheap and effective. I doubt it would poison your fish or plants, since people use aluminum oxide sand as substrate or filter media. Although if you use it with salt water it will corrode into nothing very quickly.
Overall, I think epoxy is great stuff, inert and harmless to fish or plants. You can probably get anything coated in epoxy if you know where to find a specialty shop. Such a shop could coat your copper or aluminum tube making it non-corrosive and safe.

Regards,

**PKB** · 12th Apr 2010, 11:52

Hi,

Understand that this is a 2008 thread.

Just interested to know if anyone have done up anything similar in the past 2 year? Can a mini coke (hold 6 - 8 can of drinks) fridge able to bring down the temp of a 2FT tank by about 2 degrees?

Thank you.

**Eddylimst** · 16th Apr 2010, 10:56

I think copper tube and Aluminum tube also not the good choice as your cooling coil, the best meterial will be the titanium coil. Titanium is an unactive metal, thats why they are used in all the water chiller as the cooling coil.

**BFG** · 16th Apr 2010, 15:33

The biggest obstacle to using titanium is cost.

**Fuzzy** · 16th Apr 2010, 18:27

Those mini fridges are TEM (Peltier) cooled, making it even less efficient than TEM based inline chillers, or immersed probe TEM types.

Your best bet is a larger compressor based bar fridge, or it's likely you will spend more for the power alone over a year than the price of a chiller + power for the year.

People have used regular PVC type tubing also for the immersed coil with decent results.

**marco** · 5th Jun 2010, 22:48

For those who actually made a chiller using a fridge, did you ever measure the electricity consumption using a watt meter?

**sfc** · 5th Jun 2010, 23:40

Originally Posted by timebomb

It would be great if we can group together and do a bulk order on the parts needed but I would say, let me be the guinea pig first before we start buying anything. I don't want anyone to feel let down if the thing does not work out as expected.

Anyway, I went to James' house today and took some pictures of the DIY chiller. The tank's really cold. In fact, it was so cold James had to crank up the thermostat as the thermometer was going to go below 20 degrees C. James keeps some precious show Guppies in his tank and he wasn't sure how well they take to the low temperatures.

The idea's pretty simple really but good ideas are always the simple ones. The DIY chiller involves using either a bar fridge or a small freezer. James is using a bar fridge which isn't as economical in space and less efficient than a freezer. James isn't really interested in building a chiller for small tanks so this is just an experimental DIY chiller as far as he's concerned. His next project, a DIY chiller that can cool large tanks of up to 1000 litres is the one he's really keen on. Anyway, here's a pic of the bar fridge.

As you can see, there's an inlet and an outlet pipe. It feeds directly to and from an external cannister filter which if you look closely, is at the side of the bar fridge. Using a bar fridge to cool down a tank is an idea that has been proposed and discussed many times and those who have tried it say it won't work. James made some modifications to the old idea, one of which is to replace the rubber hoses with something that is more conductive to heat. James uses PVC hoses which are flexible enough to be coiled and conductive enough to make a difference. The other significant change is to immersed the coiled hose into a tub of water. Why so, you ask? Why can't we just simply leave the coiled hose inside the bar fridge?

I'm no scientist so I can't give you the scientific reasons but this is how James explained it. Imagine if you leave a can of beer in your freezer. It will get very cold eventually but it will take some time. But if you put the can of beer in a tub of cold water filled with ice, it will chill much more quickly. The difference lies in the medium of heat transfer. With air, it's much slower. With water, the can of beer cools in double-quick time.

Here's a picture of the inside of the bar fridge:

As you can see, the space below the compartment where the tub of water stands is a waste of space. A freezer would be more space efficient as every cubic inch of the space inside can be used to hold a very long coiled hose. The compartment in the bar fridge James is using is so small the coiled hose can't be immersed fully. James also uses a small powerhead to circulate the water in the tub. Without this powerhead, there's a danger the water in the coiled hose can turn to ice. Circulating the water also ensures every inch of the hose is in contact with the cold water. Besides this, there's another very important piece of equipment too. It's the thermal plate underneath the hose. This is used for making ice in fridges. The thermal plate ensures the water inside the tub becomes very very cold. It isn't very clear in the picture but if you look closely, you should be able to see a white plate underneath the hose.

There's a thermostat inside the bar fridge which can used to be control the temperature. James set the thermostat at a reading of about 4. The scale is such 10 is the coldest and 0 the warmest. I suppose at 10, the whole tank could possibly turn into a block of ice

Here's a pic of the thermostat.

I was at James' house in the afternoon at about 4 pm. There was still some condensation on the sides of the tank. James cleaned the front piece of glass as he said he couldn't see his fish and plants with all that condensation. Here's a pic of the side of the tank.

I took a picture of the bar fridge specs. Here it is:

I'm a complete idiot as far as things like watts, volts are concerned so I don't know what the figures say. But you all should be able to figure out that a bar fridge uses much less energy than a chiller and the best thing about it, it does not give out any hot air. I know hobbyists whose tanks are cold because of the chillers that they are using but their rooms become very warm. The fish and plants enjoy but the humans suffer

.

All in all, James said it costs only about Sing $200 to build the bar fridge chiller. That would be about USD $115 for American folks following this thread. Is this a great idea or what?

Unfortunately, I will be on a 4 day course tomorrow so I can't go around shopping for the parts until this Saturday. Please be patient. When I get everything, I will post the addresses where to buy them and how to rig everything up. My good friend, Melvyn Seah who also saw the chiller in James' house is going to DIY everything for me. The good thing about having friends is when you're no good with DIY, you can always get someone to DIFY (Do it for you)

.

James said this afternoon that anyone who wishes to participate in his next project, a chiller for large tanks, must be prepared to pay for such a chiller himself. In other words, you must be prepared to fork out something like Sing $500. There's some risk that it may not work but if everything works out nicely, you should bring home a chiller that is much more efficient than a bar fridge and takes up much less space. James needs help because he doesn't have the time to go around shopping for the parts. Cost-wise, it will also make everything much cheaper if the items were bought in bulk. James is looking for a team of about 5 persons.

James explained the idea to me but being technically-challenged and a complete idiot, I didn't quite understand him. Briefly though, it involves using a compressor without the need for the fridge/freezer and hooking it up to something called an evaporiser and I can't remember what else. It is something that is unavailable in the market and involves some soldering work and piping. If you're game, let me know through private message and I will put you in touch with James. Please take note that neither James nor I are going to profit from the project. We'll just want something better than the chillers available in the market, that's all.

Loh K L

Cool men....

**nettian** · 7th Jun 2010, 13:23

up for this DIY.

**marco** · 8th Jun 2010, 22:32

Originally Posted by shortman

Wow, 70Watts for a chiller that is so far the lowest rating I could get in the market. The lowest I know for a chiller is around 110~150w.

cheers

That Rated Power 70W may not mean its consumption is 70W. Rated power may be equivalent to cooling power. A typical aquarium/reef chiller 10hp (75W) consumes more than 240 – 260W.