DIY water chiller

[+Jakedoza]

Most of you guys who know me know that I'm a huge DIY person. When I started my tank back in March of 2010 I had the privilege of sharing the back wall with my garage and I kept my chiller there and piped my water lines through the wall. Now I have a peninsula style setup and the part of the tank that sorta sits next to a wall actually sits about 30" from it, and it is an outside wall.  Here you can see how my tank sits

Please excuse the mess and the grumpy teenager on the couch, but from this vantage point the kitchen is to the left and the living is obviously to the right. The area behind the tank end the wall is actually about 30" away. The good news is that there are already holes through the masonry for a drain clean out. My plan is to build a custom water chiller that is set up similar to a home A/C unit. I will use a refrigerator style compressor that uses R134a refrigerant and I plan to use a condenser from a car. I can get one for a Honda for about $35. Mount those in a box with ventilation and a fan and run the refrigerant lines and electrical into the house to the aquarium where I'll have my heat exchanger. I plan to use my Apex to control the unit. I'm still unsure what I can use as a heat exchanger, but I thought about using just some stainless steel tubing that is coiled up that I can probably get from Austin Homebrew or someplace online and insert it into a 4" PVC pipe and seal it off with water lines flowing across. 
Are there any HVAC guys in here that might be able to shed some insight on this? I do have knowledge in this space, so I'm not completely blind. 

[Isaac]

you should drop by and check out my chiller setup.  its a one-off from chillking chillers. it might help with your setup.

[+Jakedoza]

I may have to do that!