Homebuilt Water Source Air conditioning

[peakbagger]

Has anyone every tried building a homebuilt Air Conditioning unit using cold water as the source?

I have a spare surface well that was replaced by an artesian well many years ago. Its a 4' concrete well about 17' feet deep, with about 3' sticking out of the ground. The vleev varies but I usually have a minimum of 4' of water in the bottom.When it was built we bedded it in a truck load of crushed rcok to get some storage as the surrounding soil is clay. I used it for about 10 years and never ran out of water. I also ran 2 lines from the well to the basement. For much of the year the basement is below the water level in the well so I dont need much suction lift. The water temp is never above 50 degrees, which made it chilly when I had to install the foot valve.

What I would like to do is install an air handler in a bedroom and circulate cold water through a coil to cool the room. Rather than build the handler up from pieces I would like to find something commerically built but I dont need much more than 10,000 BTUs/hr and the commercial air handlers I find are much larger. Ideally I would like to find something like the head unit from a split system but I expect that the coil sizing is a lot smaller for refrigerant than cold water. I have hot water baseboard and not a lot of room for ducts so an external handler with ducts is not a good option.

One concept was to install a split unit and submerge the condenser in a tank of water fed from a well but getting things water tight would be tricky. I expect if I did that, I would need to install a coil in my well and use a circulating fluid so the aluminum fins wouldnt corrode from constant fresh water.

Any folks have suggestions?

 

[jimbom]

Junk auto radiator should do the trick. Hook it up quick and easy and run for a while. See how fast the temperature of the supply well water changes. That will tell you if the coolth capacity in the well is sufficient.

 

[heat seeker]

A radiator should work, at least for a test. Be prepared to deal with the condensation that will form on the cool surfaces.
You might be able to use a length or two of baseboard radiator piping, with all the fins on it, and a fan to move the air over it. Perhaps a couple of air conditioning evaporators from cars would work. They have larger tubing than a car heater has, and should be available cheap from a junkyard. A friend of mine had his heater core in his car start leaking. His AC didn't work, so he connected the heater hoses to the evaporator. The heat he gets now is phenomenal! The temp control works backwards, though…hot is cold, cold is hot.

 

[semipro]

I've been looking for an air-to-liquid heat exchanger for a project to recover heat from my clothes dryer to preheat my domestic hot water. There are some pretty nice units on EBAY. The problem with standard HVAC air handlers and the coil they contain is that they are designed for a working fluid phase change.

The condensation that someone mentioned is a good thing. You really don't want to chill the air without removing some water. "Air conditioning" is a combination of cooling and humidification that is important for human comfort.

I've considered doing something like you're doing with our geothermal heat pump. I'm not sure why I need a refrigeration system if my supply water is 50 degrees F. I could use the water supply that GHP uses directly to cool and dehumidify air as you're proposed.

 

[benjamin]

Tetco makes (or made?) such a unit, a direct groundwater coil for AC purposes. I've done the same thing with a junk A coil, they already have the drip pan in place. You'll want to drill out the capillary tubes and replace them with a new manifold of bigger diameter tubing and hopefully more direct through piping, but it will work if you just duplicate the larger manifold that was originally the suction side of the coil. If you can scrounge up a water coil, you'll avoid this conversion.

Another not-as-far-out-as-it-may-seem option is direct cooling from the water to air via mist, look up air washers. The humidity will not go up because the water temp is lower than the dew point.

Ideally in northern climates AC should maximize dehumidification, which this system will do poorly, but that's a technicality if you can get by without refrigeration.