How can I figure out how to calculate the heat/cooling exchange rate of water inside pex tubing? I want to build a ground source cooling system simular to a chiller system but I want a closed loop system. My game plan is to pump ground water into a holding tank that is constantly flowing ground water into the tank and dumping back out. Inside I'd like to use pex tubing with the cooling water going to my shop inside pex tubing in a closed loop. I have a brand new air handler rated at 12 Ton for the building end. It's a bit overkill I know, but for $250 it's what I have to work with. I'm wondering how much pex tubing I need to use for my loops inside my holding tank to get at least 3-5 tons of cooling. My ground water is 60-62* F. My air temp inside the shop will be 80*F or better.This is my first post, so I'm hoping someone can lead me in the right direction without getting tossed. Thanks, Floyd.