Should I pre heat water to my evaporative cooler?

Question

If I use a black pipe and preheat the water to my evaporative cooler will it evaporate better thus being cooler?

Answer 1

No.

The water that is circulated in the evaporative cooler normally reaches the Wet Bulb temperature of the ambient incoming air after several minutes of running.
As you evaporate this water onto the incoming air stream, the Dry Bulb temperature of the incoming air drops and approaches the temperature of the Wet Bulb, or the temperature of the water in the sump, which it would do if the unit was 100% efficient.

If you pre-heat the incoming water, it would increase the temperature of the water in the sump, but then, even if the unit was 100% efficient, the incoming air could only get down to the temperature of the water in the sump, which is now higher than the normal Wet Bulb temperature.

The Wet bulb temperature remains constant in this process.
The Dry Bulb Temperature cools, and approaches the Wet Bulb temperature from above, and the Dew Point temperature of the air rises and approaches the Wet Bulb temperature from below. If you pre-heat the water in the sump, you shift all the temperatures upward.
The change in temperature of the Dew Point (it rises) of the incoming air is what produces the cooling effect.

Answer 2

No. It will still take exactly the same amount of energy to make the state transition from liquid to gas.

Doug