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It's possible if somewhat complicated. The real problem is that you don't gain much - you've still got to dump the heat somewhere.
If you've got a good source of very low temperature coolant then it would work nicely, but you've got the problem that the temperature of the liquid will always be no lower than the temperature of the radiator.
Effectively, you're exchanging increased cost and complexity for reduced fluid volume. The advantage of evaporation cooling is that since the air is not saturated, you can evaporate more water into it so getting sub-ambient cooling temperatures. As soon as you go to a closed loop system, you will always be running at saturated gas. This limits you to runnning at the radiator temperature at best.
The effect of dropping the pressure is just to make this possible - it doesn't necessarily make it all that practical.