[anotheramala]

There is a somewhat new company out of India which has an improved approach. As others mentioned, swamp coolers have been around for a long time, especially in India. They are not popular anymore but AC's are expensive.

Their approach is use the refrigerative compressor to chill water for an cooler instead of chilling the air.

The efficiency is greatly improved and they claim 10% of running costs.

https://www.thebetterindia.com/52984/vaayu-hybrid-chillers-c...

http://www.vaayuindia.com/

[brudgers]

Large buildings commonly use chilled water HVAC systems. The scale at which these systems make sense is larger than a single family residence.

http://www.york.com/for-your-workplace/chilled-water-systems

[anotheramala]

Yes I edited my comment. Looks like the approach of vaayu is to directly do evaporative cooling. So a chilled water swamp cooler. The commercial systems use the chilled water in closed coils.