Originally Posted by fart_plume
Stainless is still the better option, it won't corrode in clear water and air,(although saltwater does affect even SS).
My problem with plastic is that in order for them to be stiff enough to be self suporrting your going to lose air flow through the tower and it's is an insulator impeding the transfer of heat from the water to the air.
As far as posting a worklog, i can get some pics later of some of the components i ahve already. and grab some off the net of ones I'm looking at getting for the project.
Now a though crossed my mind(happens occasionally), is that a two stage tower maight be something to look in to. first stage cooling using salt water. Why salt water you ask because it's freezing point is 26*F, but I'm not sure if dew point is low or not if it is then a two stage may be able to drop temps even further.What do you think?
Couple quick things. The heat transfer from the water to the air is not affected by the thermal conductivity of whatever surface they may be on. The cooling is by evaporation, and is affected by surface area, atmospheric pressure, ambient temperature and humidity. As far as being self supporting, that is a point I don't quite know how to respond to. I think this goes back to the thing about thermal transfer. Basically the forces acting on the stuff inside the tower are not strong enough to move ping pong balls. Which are pretty much the lightest things I could find to use. If you are referring to having substrate mounted inside the tower, it will all have to be mounted to the sides in some way shape or form.
I realize that you wont take what I am saying as 'fact' and I am glad for this. I certainly don't accept as fact anything I read or hear without personal research into it
- The best teacher is experience, what I hope you do is start building small experiments to test your ideas. I suggest you start working out tests to determine what substrate works best for your evaporation rates. Use the ss mesh you are talking about, and also use the various other substrates that have been mentioned here. A small loop bong - say 2' high and not on any pc, just in a loop with a temp probe monitoring the water temps - and let them run side by side for say 2 or 3 days.
There are going to be things you thought of that don't work out, and there will be things that work out that you assumed would not. The only way to discover this is with test builds. (Why do you think I went and built a 'swamp field' chiller when I have a perfectly good tower style bong?
I hope your idea to adapt a commercial cooling tower design for a bong chiller works out.... anything that any of us can figure out to improve our rigs performance benefits all of us, not just the guy who did it first
About salt water. Not worth using it as it would not lower temps at all unless somehow the presence of sodium increased the evaporation rate. The dew point is the hard limit for possible water temps in one of these set ups, and unless I am mistaken, all salt would do is make the water more corrosive.
Good luck and keep us posted
(we love pics)