I'd like to break in here to ask a few questions...

What is so special about this water cooler? If your passing water to cool a beam head, wouldnt you be more concerned with input temperature compared to output temperature?
Further, would I be correct in assuming that calculating the required flow rate would be to take the rating of the power supply and design to cool that many KW?
1 Liter of water up 1 deg = 1 BTU.. ??

Am I on the right track here?

Murphy