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Energy and Evaporation

 

 

I have been studying energy and evaporation, carefully, lately. Here is what I have gathered, so far.

 

There are 2 kinds of water during a water damage situation. Free, or surface, water and bound water.

The free, surface water, like that sitting on a concrete floor, responds well to airflow. The water molecules get separated and allows, relatively, fast drying.

Bound water, within the fiber structure of a material. is relatively unaffected by airflow. The moisture is "protected" from its affects.

Evaporating of water, in a porous material, speeds up when temperature is increased at the wet material surface. Ask any water damage technician, who has done daily monitoring of flood jobs. If three rooms are wet and one room is hotter than the other two, the hotter room will be drier.

My pool, in humid Houston, needs constant filling, during the 100 degree days of summer. Dry air, certainly doesn’t cause it. Higher temperature is the culprit!

A water drop is made up of septillions of vapor molecules. These vapor molecules are bonded to the water drop.

 

Here’s what happens.

The vapor molecules move faster with temperature increase. The faster they move, the more heat there is. The movement is in hundreds of mph. The vapor molecules can be moving at different speeds, crashing into each other. Temperature is a measure of the average kinetic energy (caused by movement) of the molecules. This speed and crashing creates vapor pressure.

When the molecules move fast enough they fly away from the drop. They escape the “hold” the drop has on it, going out into the "space" in the chamber or room.

This is why warm air has more water vapor.

 

As air is cooled, the vapor molecules slow down. The slower they move, the less temperature or the less energy they have. When lowered, this makes them re attach as water drops. Not enough to remain free. This is condensation. Condensation happens at the dew point.

 

Evaporation happens at temperatures above the dew point. More temperature; more vapor molecule speed; more vapor molecule speed, more heat,  the greater the escape of vapor molecules from each drop of water……. faster drying.

 

Airflow can carry heated air to the wet surfaces, re supplying what was taken away by the escaping vapor molecules.

 

In cool, calm conditions very little evaporation happens. In fact when you cool vapor enough the molecules might stick together to become a crystal of ice.

 

The driest place on earth is Antarctica. It's the world’s largest desert. Due to the low temperature, there is absolutely no evaporation.

 

Jeremy Reets theory takes into account the difference between the high pressure of a hot, wet surface and the lower vapor pressure of the ambient air and assigns a vapor potential number. Typical methods of dry can have a potential of 1.5. Heat can move this to 8 or 9.

This tool, combined with what you are already doing, is powerful.

Power drying is the way of the furure!

 

  
Copyright 2012 by Dennis Klager