Rainbar Vs Fan

[shadowfax23]

Just thinking aloud:
A fan helps to lower the temperature of the tank by facilitating evaporation which subsequently cools the water. The fan does not chill the temperature of the wind it creates but causes ripples on the water surface, giving the water molecules more kinetic energy to change into their gaseous state... blah, blah......

A rainbar when placed above the water surface, can also cause agitation, doesn't this help in evaporation and subsequently lowering the temperature of the tank as well?

Any comments, folks?

[bclee]

[quote:da796048e2="shadowfax23"]Just thinking aloud:
A fan helps to lower the temperature of the tank by facilitating evaporation which subsequently cools the water. The fan does not chill the temperature of the wind it creates but causes ripples on the water surface, giving the water molecules more kinetic energy to change into their gaseous state... blah, blah......

A rainbar when placed above the water surface, can also cause agitation, doesn't this help in evaporation and subsequently lowering the temperature of the tank as well?

Any comments, folks?[/quote:da796048e2]
It is not only agitation that causes the water evaporation. The moving air across the water surface carry the water vapour molecules away rather than having it diffusing away. My fan do not really agitate the water surface but gently blowing across the surface of the water. It is effective enough to reduce the temperature by ~3°C.

Having a rainbar should help. On top of it, air movement will contribute too. But the lowest limit you can go is the wet bulb temperature.

BC

[vinz]

The fans also help to move the warm air under the lights away from the tank.

[Aeon]

Fans transport the water vapor saturated air away and replace the area with new air constantly. This accelerates evaporation whereby the water molecules are lifted off and energy released into the air as heat. The air that comes from the fans are actually hotter (heat from motor).

[james]

Just a side note though. If this is a planted tank, too much water surface agitation would cause CO2 escape.

[vinz]

[quote:19a96b9cfc="Aeon"]Fans transport the water vapor saturated air away and replace the area with new air constantly. This accelerates evaporation whereby the water molecules are lifted off and energy released into the air as heat. The air that comes from the fans are actually hotter (heat from motor).[/quote:19a96b9cfc]

Just to clarify... hotter then what? I don't think it's hotter then the air under a full set of lights for an unventilated tank.

[bclee]

[quote:41f7cfb6b2="Aeon"]... the water molecules are lifted off and energy released into the air as heat...[/quote:41f7cfb6b2]

Heat are actually absorbed by the water molecule as latent heat of vaporistation when water evaporate. Therefore, the temperature lowers. It is not really energy released into the air.

BC