Evaporation requires the removal of heat?

[dynamicproject]

I'm missing out on something here.

I'm studying how the cooling tower works and it says that the "water evaporates and removes heat". The thing is, shouldn't the heat be added to the water for it to evaporate and thus increasing the heat? If we want water to evaporate, we boil it with fire, which is once again heat addition.

Care to clarify this for me?

 

[mpv_plate]

Water needs heat to evaporate, but the heat does not increase temperature of water: the heat is used to free the water molecules. It is called the latent heat. Water gets this latent heat from the sorrounding material, so the sorroundings get cooler.

 

[ModusPwnd]

We boil it so that the water is hotter than the air and then it evaporates quickly. If we don't boil it then it will be room temperature, and it will still evaporate. This is because water has many molecules in it and some are more energetic than others. The "hotter" (more energetic) molecules and bits of water have enough momentum to escape the liquid and go into the atmosphere. This leaves the liquid cooler because the hot molecules have escaped. This should jive with your personal experience. If we boil water it cools down as it evaporates, the hot water is leaving. If you sweat you cool down because the hot water molecules on your body leave and what is left are colder molecules.

 

[dynamicproject]

Thanks to both of you but the answer I was looking for was answered by mpv_plate. Appreciated!

 

[sardar]

Yes, evaporation does require the removal of heat. When water evaporates, it changes from a liquid state to a gas state. This phase change requires energy, which is provided by the heat in the surrounding environment. As the water molecules gain energy from the heat, they become more energetic and eventually have enough energy to break free from the liquid and become a gas. This process of evaporation removes heat from the surrounding environment, which is why it is often used as a cooling mechanism. In the case of a cooling tower, the water is constantly being circulated and exposed to air, allowing for continuous evaporation and heat removal. So, while the initial heat addition may be necessary to start the evaporation process, it is ultimately the removal of heat that allows for the water to fully evaporate and cool the surrounding environment.