chiller build

[segraves1]

For my 110gal (~180gal total system tank/sump volume) setup, I am going to build myself a chiller from a window AC unit. I feel that since I have the capacity to TIG weld stainless, there is no point in my spending $500+ on a chiller when I can build one for a little over $150 (HomeDepot has 5000BTU AC units for $89).

My plan is as fallows:

to buy a 5000BTU unit, take everything out of the "housing", and scrap everything but the required parts (AC pump, condensor, and acumulator....I will ditch the evaporator since it is copper and as we all know, copper + inverts don't mix)...

I will then take a 8foot stainless tube, wrap it into a coil (of some shape), and weld stainless fittings on the ends.....this will be the new evaporator that will then be submerged in the sump....

connect the evaporator to the rest of the system with high pressor rubber lines (such as would be used on automotive AC systems) and have the new "unit" recharged....

this SHOULD provide a quite reliable (since the only part in direct contact with water will be stainless) and effective "chiller" at a fraction of the cost...

does anyone see anything wrong with this?

is 5000BTU large enough ( looking at these chillers:
http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=13127&N=2004+113768

5000BTU/1/3HP seems to be plenty)

should I go up to 6500BTU (HomeDepot also has a 6500BTU for $125)? above 6500BTU, the cost goes WAY up (jumps to 10,000BTU and $500)...

[dakar]

Sounds like a fun project... What are your plans for the actual heat exchange?

[segraves1]

I plan to extend the lines for the evaporator (the hot side of the system) so that the evaporator can be mounted up in the canapy (open top canapy) and thus the heat could rise right out the top (along with the heat from the lights).....

THE PROBLEM.....is I ran into a snag.....window AC units (went and got the 6500BTU this afternoon) don't seem to be designed to be rechargable in that they do not have the fittings to connect up recharge equipment.....and thus there lies the problem...once I cut the lines to do my conversion, I will need to recharge the system........

now I THINK I should be able to get some of those fittings (went outside, looked at the house AC unit, and its fittings are copper/brass) and thus install these into the copper lines of the window unit.....but my question is WHERE? I would guess a local home AC repair company would have those right?

[dakar]

I would think so... do note that most juctions for A/C are done by using silver solder and not just out regular tin/lead solder.

What I meant for the heat exchanger was from the 'water lines', got some drawings or something?

[perpetual98]

Check this thread out. Kinda cool...

http://www.myreef.com/smf/index.php?topic=13

[segraves1]

Check this thread out. Kinda cool...

http://www.myreef.com/smf/index.php?topic=13

thats almost exactly what I'm trying to do, though my plan was to just mount the stainless coil in the sump (let it just "float" in there)....