Cooling Tower?

[bprewit]

Gas plants and electic plants use cooling towers to cool water used for plant process. Basically water is pumped in the top, flows down through numerous baffles while large fans pull air from the bottom exiting through the top. Wonder if some large diameter PVC with baffles and a big pancake fan mounted at the top wouldnt work for a cheap-o diy chiller that draws very little power? I guess problem would be making it fit under a tank with already too many things crammed into a small space.

[NaCl_H2O]

Been there, done that!

See This Thread (http://www.maast.org/index.php?name=PNphpBB2&file=viewtopic&t=5840&star t=0&postdays=0&postorder=asc&highlight=)

I built a small cooling tower along the lines of what you decribed. It provided some cooling, but the size required for substantial cooling and the humididty created are not reasonable IMO.

[GaryP]

That's basically what we are doing by adding cooling fans in our hoods. Exchanging cooling for evaporation. If you look into the thermodynamics of evaporation you will see there is a lot of energy (heat) given up by water when it goes through the phase change from liquid to gas. One of the things we don't take into account in our homes is humidity. Evaporation slows when the humidity is high. The time of the year when cooling is more of a problem isn't summer. Its in the fall and spring when the weather is cooler and I have my windows open and the air in the house is more humid than in the summer when I have the AC on and its removing humidity in the form of condensation at the AC compressor.

gary

[::pete::]

DIY Chiller (http://reefcentral.com/forums/showthread.php?s=&threadid=488116)

[bprewit]

I have actually made a diy chller like the one in that link. I used cheapy fridge from wally world and took a container full of antifreeze which I coiled the tubing around in, holes in the door for the inlet outlet and it worked pretty good on 55g tank.
I live in west tx where humidity isnt really a problem....but **** it gets hot. I am running one 250w mh on my tank right now and have no problems but am in the process of building a 250g tank that should be completed early next year. I have 3-400w MH and 2-72" VHO that I am putting over this tank and I know I will have some heat problems so was just trying to think ahead a bit. The only for sure way is a chiller and I know this but have already spent a buttload of cash and as always im a tight wad and looking for cheaper way out. If there were room under my tank for a large enough cooling tower with efficient design I have no doubt that it could drop the temp but would take a large amount of space and also some major evaporation would be happening.

[NaCl_H2O]

One of my tanks (215g) has 3x400w MH & 72" VHO, just as you are planning. The heat generated by the 400s is AMAZING! I don't believe evaporation alone is going to do it for you, unless you can live with 10+g/day of top off water!

Can you get to an outside wall? Look at commercial cooling tower designs, these are basically huge evaporative coolers. If you had a cooling tower outside, using tap (or RO/DI) water with a top off device, and pumped saltwater through a submerged titanium coil in the cooled water, it might approach your needs. However, the size and evental cost would probably make it worth while to just consider a real chiller? I toyed around with this using a glass coil or glass tubing for the heat exchanger.

Let us know what you do (or even try).

[prof]

Can you get to your fridge? You could run tubing through any normal household fridge. The temp. drop would be dependent on the amount of tubing. It would work pretty well, I think...

You could use a temp controller on your pump and there would be less evaporation.

Sorry for the quick ramble...someone should try this...

[bprewit]

Chillers are so **** crazy expensive! For a chiller designed for a 250g tank you can figure on spending $500. Thats just a bit extreme to me, but any low volume sale item is gonna be pricey I know. I am going to visit with local heat and a/c shop next week about building a real chiller. 5000 btu window unit a/c sell at walmart for around $100 and even cheaper at garage sale, local classifieds, etc. I dont see why the compressor from one of these couldnt be used. Why not use a stainless container filled with DI water, plastic tubing coiled inside with a input and output, and the coil from the compressor wrapped around the outside of this container. Seems like you could build a large chiller for way less than $500 that would be dependable and last quite a long time. Replacement parts would be pretty easy to come by as well, and if the compressor ever croaks it would be back to wally world for a replacement vs. waiting a couple of weeks for parts from a chiller manufacture. I will do some checking and post if I can come up with something feasable, already have a little window unit ac sitting in the garage gathering dust.

[GaryP]

The problem with a standard compressor is that it has copper coils which could be toxic to a lot of inverts. That's why they use titanium coils on aquarium chillers.

Gary

[bprewit]

cool thing is, the copper coils could be submersed into a container containing water/glycol mix. The A/C coils would cool this water to approx 40 degrees F and tank water could pass through a seperate coil of flexible tubing that is in the same container. The water/glycol mix should be excellent heat transfer, absorbing the heat from the tank water as it passes through the tubing, transfering it to the copper coils from the a/c.
My tank is sitting right up against a exterior wall, so the whole chiller unit could be installed outside in a small enclosure to minimize noise and heat from that unit.
Bottom line I know is I will spend more on this project than I would buying a definate working chiller but where is the fun in that??

[GaryP]

OK, that would work. I have thought of doing something similar. The only problem with a plastic tubing coil is that the heat exchange capacity is low for plastic. The way to overcome that is with more surface area.

Have you thought about doing an in-ground passive cooling system? I knew a coral farm in New Orleans that did that. Its harder to do that here because of the rock. In some areas it would take a rock trenching machine. You don't have that problem in Andrews.

Your only energy cost would be the pump to push the water through some PVC tubing buried in the ground. The temperature at 6 inches deep stays at a pretty constant temp. year round.

Gary

[::pete::]

Gary
There was a reefer in NC that was building a house and he buried the 55 gallon drums full of tubing below his basement floor!! He also put a footer in under his tank and steel I beams up to support the area. :shock: A little over kill, but I thought the cooling idea was pretty cool.

[prof]

Search ebay for cooling coils. I see stainless and titainium coils out there every once and a while.

[bprewit]

Hmm found 50' length of titanium .5" OD tubing for $50 on ebay, and large fridge compressor, 120v-1/4hp new in box for $25. I suppose could actually mount the condensor and fan outside, like a home a/c unit, and mount the compressor and evaporator/heat exchanger under the tank. Would make for a definate permanent installation but should actually work pretty good. with a temp controler that basically kicks a relay to run the circulating pump. For a permanent type installation a small length of schedule 80 6" SS pipe with water/glycol mix, copper evaporator coil wrapped inside, titanium tubing inside, filled with water/glycol mix. The compressor would cool the fluid which would cool the aquarium water running through the tubing. Figure $150 for the pipe, tubing, and compressor and then use the condensor I have that came from old ford torino. I can sweat all the copper tubing connections for the compressor and actually have a vacuum pump and gauges to fill the compressor with R134A freon. 1/4hp chiller for under $200 and designed to fit in my stand dosent sound like a bad deal!

[NaCl_H2O]

I would be very interested to see how this turns out? If you do it, document it well and post the design & results!

Keep us up to date, good luck!

[GaryP]

I had a phone conversation with Mikeyboy about this today. He has access to some chillers at work and was wondering about the possibility of retrofitting them with a titanium coil. Sounds like a good DIY project.

Gary

[NaCl_H2O]

Gary
There was a reefer in NC that was building a house and he buried the 55 gallon drums full of tubing below his basement floor!! He also put a footer in under his tank and steel I beams up to support the area. :shock: A little over kill, but I thought the cooling idea was pretty cool.

Did it work? I have always thought the buried tubing would be a neat cooling system.

Let's dig a huge hole in somebody's backyard (not mine) as an experiment :-D

[Ram_Puppy]

I always have kind of wondered, if I ever build a house from the ground up, about just building the sump right into the foundation.