Cooling Engineer needed for question

Hi:
I've been talking to an engineer friend of mine about the old way to air condition (compressed/evaporated water), and he thinks i might have a good idea and is willing to help me build it.
I have figured out how to compress water enough to evaporate it on the low side of a capillary tube, but i need to know if it is feasable to implement this into a self-contained computer chiller of sorts.
My idea is this:
Place the evaporator inside a "sealed" case, such as thus the components are air tight, add water to the system, seal it, pull a vacuum to the water to maybe just 15mmHg, then turn on the compressor/condenser fan and see how cold it would get.
I know its tough to get water to vaporize in this way, but im sure the pump i have will do it (I tested it by connecting a 3/8" nylon tube to the outlet, filling it and sealing the outlet. Needless to say, the tube blew up like a balloon and exploded within seconds).
So, my question would be is it possible?

It sounds like you are just talking about making a regular phase change system but using water as the refrigerant. I'm sure it could be done, but the high vacume you need to get water to boil at relativly low temperatures would mean that you would need a very long cap tube and the system would have virtually no capacity. A higher capacity method that uses water evaporation is a bong cooler. If you want to use water, that is probably the most effective way to go. If you want to use a phase change system, just use propane or another refrigerant if you have a licence.

This idea can only aproach ambient temperatures but never go under. The vapochill micro just about does exactly what you are trying here. With a home made system, you probably won't be able to beat a good air heatsink.

Now if you are trying to compress the vapor and insert it back into your waterblock/evaporator while simultaniously drawing a vacuum within the waterblock/evaporator then you are making a phase change system and you are really wasting your time and money by not just making a real phase change system.

Since you have the ambition, get yourself a refrigeration compressor off ebay ($30) some r134a from your local auto parts store and have some fun.

Labrat23:
I think it would work with the long cap tube like matt said, and it could go deep depending on the capacity. It must work because the building i work at used to have one until the 35 ton compressor blew out. From what i hear, the newer setup, where 2-20 ton comressors running r22 replaced the 35 ton water unit, doesnt actually work as good as the water air conditioning did back in the day. I inspected the system, and found that all the pressure piping was 2 1/2" copper, with the cap tube only 3/8" thick wall tube.
Basically, i want to minimize this system and use it to cool my comp.
Matt:
Any suggestions on sites to look at for this type of system?
Thx
PoX

Well I never knew water was used as a refrigerant. Interesting, I might have to read up on that. I would guess though, that a r22 system would be easier to build, but I would love to see what results you can get with this.

I really don't think it is feasable to consider making a phase change system and using water as the refrigerant. A lot of compressors can't even pull enough vacume with no flow at all to make water boil at even ambient temperatures. Using say a 1 hp rotary compressor you might be able to cool something like a 5 watt heat load to maby a couple degrees below ambient, but you can forget about cooling a CPU.

I'm interested about how this water AC system worked. I'm quite sure it wasn't just like a regular phase change system.

I would suggest you do the same thing as labrat, make a regular single stage phase change unit. I'd recommend R290 (propane) over 134a as it will give way lower temperatures, but use whatever you want.

Well I never knew water was used as a refrigerant. Interesting, I might have to read up on that.

Click to expand...

It can be, but not for PCs. Water boils at too high a temperature. It can just evaporate slowly at reasonable temperatures, but it's not very practical for CPU cooling. I'm not aware of any major application that actually boiled the water. Maybe a few specialty engines or solar source heat pumps, but I've never encountered one of those.

I'm interested about how this water AC system worked.

Click to expand...

The A/C system installed at my old house used water. It just used a pump to pour water on some special filters. The water would evaporate as air is blown through the filters. It works well in arid climates as long as it doesn't get too hot.

The A/C system installed at my old house used water. It just used a pump to pour water on some special filters. The water would evaporate as air is blown through the filters. It works well in arid climates as long as it doesn't get too hot.

Click to expand...

Exactily what I though. This is just a evaporative cooler, which is the same thing found in Nuclear power plants, some large buildings, and bong water coolers.

Everyone:
Cooling with water worked in the evaporator now being used in the cooling of my building right now. The very same evaporator was used in the new setup as the old.
The compressor was mounted close to the evaporator, and used about 220 amps at 220 volts (a big load). This thing is so big, when they converted it, they left the compressor upstairs because it probably weighs in at about 800-1200 pounds.
Matter of factly, i contacted one of the oldest HVAC engineers in the area, and he said he had worked on this system before, way back in the 1960's, and he is willing to help me get my figures right. He also said, that with the right setup, you can cool with a system like this to 15ºF below ambient. When i find out more, ill post in a different thread.