This is a dig, but I think might be relevant to those of us in the Hobby.
There was mention recently of a new evaporative chiller that works well in our climate, doing 58k btu/h with just 1.4kw of power use.
http://airbitat.com/
This looks to be quite the breakthrough technology, and would be perfect for chilling our ponds. Piping chilled air through a waterfall, or titanium heat exchanger for instance would work pretty well.
I emailed them to check cost. About S$9k - which is the same as 2 Artica 3HP coolers (64k btu/h) running @6kw.
They apparently have a unit running at the Zoo entrance. Will go check it out to see if it is all it is mentioned to be.