Heat Generation for Reci tubes & Peltier Performance

[Tech_Marco]

Look forward to see your experiment doing well !!

Marco

[medicdude]

Thanks Marco! The tips and recommendations have been very helpful

Here's some pictures on a 'superbong' someone built for PC cooling, mine will be very similar, I might have to steal the clear pipe idea: http://www.ku74.net/uberbong/

I'd probably go with a shorter but wider model, or multiple tubes, to reduce the static head against the pump.

[medicdude]

I'm thinking of putting a UV germicidal lamp inside the bong to kill algae & bacteria. And a filter for dust & contaminants. Probably just stuff a plastic shower loofah below the air intake, at the top of the reservoir, and replace that every so often.
Best I found on Ebay: http://www.ebay.com/sch/m.html?_armrs=1 ... UV&_sop=15
Heed the safety precautions with UV lamps. Also think about ozone production and plastics breakdown. These really low power lamps shouldn't be a problem. Might want to combine your bong exhaust with your laser exhaust system.
UV lamps operate just like flourescent lamps, using the same type of ballast, but they use a quartz tube that permits the UV light to exit. 9W uv lamps are pretty common, and they can run off the same 9W flourescent ballasts you find for CF9W, G23, PL-S 2pin lamps. Best kit I found was the $20 '9W Germicidal UV 254nm Lamp & 120V AC Ballast Kit' found here: http://www.rexim.com/pages/ccfl/hfuv.html

[Axeman]

You could save money by just having .999 silver coiled wire in the water to have a passive low cost solution for algae and nasties. I've recently moved to that since liquid germicidals only kept them at bay for 4 months before they gave up.

Looking forward to seeing your results! I'd try to crunch some numbers for you but I'm only taking Thermodynamics next year

[medicdude]

Thanks axeman, have you been using the silver wire? Is it working well for you?

My hurdle right now is finding a DC power supply for the peltiers, I'm looking at least 800W, preferably 1600W, but with variable voltage control. A single commercial supply with those features has been pretty expensive from what I've looked at. I was thinking of paralleling some PC power supply +12V rails then finding or designing my own DC-DC PWM converter. I could design the whole power supply, but that's going to take some time. For anyone interested,here's a pretty well written guide about power supplies on Hardware Secrets.

[baccus61]

I have a small peltier cooler for an aquarium but it doesn't really do the job. I also have the water flowing through a 14" long radiator with 2 fans on it which also doesn't do the job very well.
I am, in the future, going to buy a small bar fridge and drill some holes in the side of it and set up a tank inside with water and a coil of copper pipe in it. bar fridges here cost about $420 so it's pretty cheap and I can use it to keep drinks in it as well. Just turn it on a few hours before you want to use it or the previous day to get everything cooled down.
We get temps here up around 45 degC which heats up the iron shed to about 53 degC so it gets pretty hot and the temp drops to about -4 in winter. Not as extreme as some places but it is extreme for a laser.
The best temp for cutting is about 16-20 C. If the temp gets over about 30 deg there is a big drop off in power which you don't want when you engrave a large mirror for 3-4 hours.
That's the next thing on my list of things to do when I get the time.
Rich.