DIY Chiller

[stormhawk]

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.

[stormhawk]

The bar fridge method should be able to cool down a rack of killies tanks to keep all the fishes and mosses happy.

Well for starters, not all killies like the cool temperatures but certainly with the use of this bar-fridge chiller, we can broaden our choices of species. Maybe now we can start scheming on keeping those coolwater killies.

[timebomb]

The Diapterons are now within our reach . There's also some discussion on Killietalk about Austrolebias nigripinnis which was found to live in waters as cold as 5 degrees C.

Loh K L

[ruyle]

James' chiller is way cool! Hey, look, goosebumps! KL, give our thanks
to James for condescending to show us all this condensation I'd be very
interested in checking out his CO2 system, too!

Regards,

Bill

[whuntley]

I was going to just lurk and learn, here, but must correct something said a couple of times.

A bar refrigerator or freezer will warm the room, exactly like any other chiller. The amount depends on the efficiency and Wattage, but TANSTAAFL.

All refrigerators, air conditioners and chillers are heat pumps that pump heat out of one place and deposit it elsewhere. Refrigerators often just dissipate the heat with stationary coils in contact with room air. Chillers sometimes increase efficiency by blowing air past the hot coils. The process is the same. Efficiency may differ.

In Fremont, I had 150 tanks and containers going, so chilling each of those wasn't practical. I installed a small window air conditioner in one corner of my fishroom, and put Diapterons and similar cool-water fish in tanks right in the outlet air blast. All the tanks were kept a couple of degrees cooler in summer, and the ones getting the direct air blast were down several degrees. What is more, the hot coils were outside, heating the back yard, and my fishroom was the most comfortable part of my house.

I also had air to all tanks. Our lower humidity made that an effective supplemental cooling effect. Probably not worth a lot in Singapore, Hawaii or Puerto Rico.

The downside was my electric bills (CA had "deregulated" utilities -- HAH!) and the increased need to have a UPS to keep air going during rolling blackouts.

I see no mention here of the use of Peltier cooling. For a small isolated tank, it can be very efficient. The guts out of one of those portable 12V heater/refrigerators can pretty easily be adapted to the back of a small tank. Has anyone explored that as a cheap way to cool a killy tank?

Wright

[stormhawk]

Wright, you mean using those cooling coils? I've seen someone do it before but its pretty unsightly. It was on a topic I read a few months ago elsewhere. They were discussing cheaper ways of cooling a tank.

[RonWill]

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

I believe the reason why some experiments didn't work as efficiently was the lack of conductive materials, insulation and void space.

James uncanningly got most of them right. Rubber hoses aren't the best material for conducting heat or cold, definitely less conductive than copper tubings, but by immersing a lenghty coil of hose in water, allows the passing current to cool off more rapidly (since water conducts heat better than air). Lengthy and smallish diameter of the coil is more important than a short huge-diameter hose.

Similar to concepts that apply to UV sterilization, it's the duration of exposure and flow-rate within the unit that makes it effective.

Aside from the tub containing cold water, this mass/bulk reduces the amount of void space within the bar fridge. Filling up the lower unused segment for 6-packs, white worm cultures and fish food will further reduce the empty space. IMHO, that will make the design even more efficient without having the thermostat kick in too often (not forgetting the nice cold soda or malt :wink: )

Returning water via rubber hose is not the best but it's cheaper than insulation foam over copper pipes (similar to those connected to compressors for multiple-unit air conditioners).

I suspect that the powerhead is optional since the passing water (through the coiled hose) will displace the ambient 'heat', there shouldn't be a chance for the tub to freeze. What it will do is, to provide circulation so that the thermostat gets a more accurate reading, cutting off at predetermined dial-settings (the dial isn't set for Degree Celcius reading).

My hunch tells me that if the present prototype can reduce tank's temp to 20ºC, it will work just as well for larger tank capacity if a water vessel, large enough to occupy both freezer & fridge segment, can be used together with a even longer set of hose.

To be able to achieve 22ºC in the tank is very good but that's excluding heat generated from more circulation powerheads, filtration pumps and metal-halide lamps.

I have no need for an aquarium chiller now but my curiousity needs to be quenched. To be able to participate in the DIY, even if it's to rig these up for others, will be a fun experience.

Let me know if James need an extra pair of hands.

[stormhawk]

Ron, I think a bar fridge would look neat at your rack. Mini beer refrigerator perhaps? Dual purpose, apart from super-cooling your main system.

[RonWill]

Ron, I think a bar fridge would look neat at your rack. Mini beer refrigerator perhaps? Dual purpose, apart from super-cooling your main system.

Jian Yang, I was actually thinking along the line of combined chiller for tank and beer fermenting but any blind man can see I'm quickly running out of 'free' space :wink:

[PohSan]

Ron, I think a bar fridge would look neat at your rack. Mini beer refrigerator perhaps?

Think that is no more space after filling up with all his cultures.

PS: Now I remembered that I missed the beer yesterday night.

Regards,
Ong Poh San

[stormhawk]

Poh San, its not just the culture. His new 2ft sump already took up HALF the bottom area so a bar-fridge would be pretty squeezy. Shucks, if it was up and running we'd be having a mini pub at Ron's Corner.

[timebomb]

A bar refrigerator or freezer will warm the room, exactly like any other chiller. The amount depends on the efficiency and Wattage, but TANSTAAFL.

For those who may be wondering what TANSTAAFL stands for, it means "There Ain't No Such Thing As A Free Lunch".

Hey, Wright, can't you be wrong for once .

You're right as usual. I didn't mention that there's a heat transfer because it wasn't a big deal to me. But if the folks like to know, the sides of the bar fridge feels hot to the touch. It's so hot, in fact, you can't touch it for too long or your fingers will get cooked . But it's not anything to worry about. It's hot, not because of the modifications, but that's how the fridge works.

Loh K L

[whuntley]

Wright, you mean using those cooling coils? I've seen someone do it before but its pretty unsightly. It was on a topic I read a few months ago elsewhere. They were discussing cheaper ways of cooling a tank.

No, I was referring to the little flat thermo-electric plates that use the thermocouple effect backwards to move heat from one surface to the other. They have become quite cheap and efficient in recent years. There are even some made to chill the CPU for home computers.

You need a finned aluminum heat sink on the air side, and thin glass to keep from insulating too much from the water side. I doubt if the cooling would stress glass enough to break it if you use good heat-sink compound to assure uniform contact.

Basically, you apply up to 12V across the thin plate, and one side gets cold while the other gets hot. Reverse the voltage to switch from heating to cooling. The entire thing, built into a portable picnic cooler, costs US$40-60 here, including a fan and heat sink! I think the CPU coolers are even cheaper, but haven't priced any lately.

Wright

[PohSan]

Talking about CPU cooling, I ever came across an article from a PC magazine that discussed on CPU cooling with water and coolant with compressor. Seem like today's CPU is getting hotter and maybe in near future, all PC come with standard coffee maker and warmer.

Regards,
Ong Poh San

[RonWill]

Wright, the cooling coils that Jian Yang mentioned are similar in design to the heating element found in kettles. I've seen those cooling coils in seafood restaurant's tanks, where there're lobsters and other delicacies waiting to land in the wok.

I first heard of Peltier cooling whilst learning to stretch my dollar (or CPU's limits ie. overclocking) but didn't follow the application for tank cooling. I think the limitation to that was controlling the desired temperature.

Seem like today's CPU is getting hotter and maybe in near future, all PC come with standard coffee maker and warmer.

Poh San, your PC already comes with a ejectable cup holder (cdrom tray ) If you miss the beer, swing by the week after the meeting at Eco's. It should be well chilled by then.

[A.Rashid]

any blind man can see I'm quickly running out of 'free' space :wink:

Ronnie, perhaps since he's(Jiangyang) alway there at your house why not make him to some spring cleaning and get things reorganised. And perhaps the laundry poles can use a retractable thingie mounted to the ceiling. :wink:

[whuntley]

I first heard of Peltier cooling whilst learning to stretch my dollar (or CPU's limits ie. overclocking) but didn't follow the application for tank cooling. I think the limitation to that was controlling the desired temperature.

That's the easiest part. I always wanted to do a design that heated and cooled. For simple cooling control, you can use a modified aquarium thermostat and a NC relay to just turn the unit on when the system calls for cooling (the thermostat switch opens).

A controller that reverses voltage to do both is a slightly trickier problem, I think. (2-pole, double-throw relay? SCRs?).


Wright

PS. Burned out heaters can make excellent thermostatic controls. Short-circuit the heater connection and find the side of the line cord that was attached to the heater and not the switch. Cut that wire at a convenient spot, and install a simple 2-prong socket to the two ends that you can plug any simple (non-thermostat) heater into. Great for an under-tank reptile heater.

[CM Media]

Wow!

This project comes just in time! I was searching for a chiller for the past few months and was sort of put off by the high output of heat generated by the chiller.

I'll like to take part in the project and build one for those demanding killies! If possible count me in.

I'm checking with a supplier for secondhand mini fridge. Those who are interested, please write down your name. I'll then talk to the supplier but no promise. :wink: I presume the cost should be around 50% less as compare to a new mini fridge.

[PohSan]

Let me starts the list:

Mini Fridge
-------------------
1) Ong Poh San (budget:S$100)

Regards,
Ong Poh San

[bad_boyz]

Hi Loh K L I already have a mini bar. Can u find out from James what els i would need and how much would it cost? Thanx