Spray pond evaporation

You also need to know the relative humidity (RH) of the air. The higher the RH, the less the water will evaporate. It's like trying to dissolve salt in water - the nearer the solution is to saturation, the less "new" salt you can dissolve.

Airflow also comes into play. If the air is moving, the newly-formed water vapour is moved away, "making room" for more to evaporate.

the relative humidity and flow of air is known but how can the quantity of water is estimated which is evaporated due to slight high temperature of the water in the spray pond. I mean the formula to calculate the volume that is evaporated in one hour

Would all so depend on the amount and how the water is being sprayed. The finer the mist the more surface area exposed to that quantity of water. Which would increase the amount of evaporation. If you are considering this in a natural environment nether the ambient temperature or the water temperature will stay constant. As soon as you start spraying the air will give up its heat to the evaporating water dropping the air temperature surrounding the spray over your pond. The un-evaporated water will also cool and dropping back in to your pond will decrease the temperature of the water.

Your are really asking: how much water will I have to replace when using evaporation cooling. Isn't it?

If you can cool the body of water by the means that you are using/suggesting you will reach a point of equilibrium at some stage. The amount of water that evaporates from the pond will decrease as the water will cool down. Less water will be evaporated when the water source is cooled. Did I get that right?

A bit more information would help, as others have said. Good luck, Ky.

The tools needed are a set of steam tables, a psychrometric chart, and some way of measuring ambient air temperature and humidity. The rate of evaporation is also influenced by matters such as barometric pressure and local wind velocities.

When the temperature of the water in the spray pond is equal to the wet-bulb temperature of the ambient air, the air is said to be fully saturated, and no evaporation or condensation takes place. So knowing where one is on the psychrometric chart is paramount.

One needs to know the purpose.

Evaporation can be used to cool the water or it can be used to evaporate treated effluent with high soluble solids and unfit for use in gardens/or discharge in drain.

Solar pond is one option for evaporation but needs large area and good shunshine.

It may be wise to combine a solar pond with Cooling tower . If it is force draft you can get to about 5 degree C above wet bulb temp . It can be narrowed with more expensive types. Other option is to use natural Draft Cooling tower where the difference can be as high as 8 degree from WBT.

So water needs to be heated by some natural process /waste heat to Evaporate via a cooling tower effectively.