[dremd]

Originally Posted by thumperoo

You can also look at these marine units. Self Contained Marine Air Conditioning Systems - Prices & Specifications
They run on water pumped from sea (saltwater and crap from harbour). They just have good quality strainers and baskets to filter out nasties. Look at the condenser (tube in tube) at bottom of web page link - looks like what you are trying to do.

Those guys are the exact reason I started this though (hopefully physical soon) journey. I figure that if I run more feet of similar exchanger I should be able to up heat transfer, but large copper is $$$, so add feet with PEX around small copper carrying the refrigerant.