Evaporation has always been the bottleneck of drying.
IICRC teaches us the four principles of drying are: Extraction, Evaporation, Dehumidification and Temperature Control; all still true! It’s also understood by most water damage restorers that up to 97% of the water can be removed from the structure, carpet, and pad with good extraction (usually within two hours of arrival on the job).
It’s evaporation of the remaining 3% of the water that’s taking too long! Even with good temperature control, air movement and dehumidification, most restoration companies are reporting 3 to 5 days for total drying.
New understanding of science
The Reets Evaporation Method teaches us that “temperature control/ increase” in the water is what will really accelerate evaporation. The more energy/heat that can be transferred directly to the water, the more vapor pressure will build in the water. As the vapor pressure in the heated water builds, it rockets past the vapor pressure of the ambient air; the greater the separation of vapor pressures in water and air, the faster the water will turn into a vapor-gas (humidity).
Application of new technology
The key to transferring heat into water is to contain the heat where the water is (carpet, pad, substrates, and walls).
This can be accomplished by directing the heat either under the carpet or by tenting the floor with plastic. The plastic and/or carpet containment energizes the wet surfaces and materials with heat, which builds vapor pressure in the water. The higher the vapor pressure in the water – the more rapid the evaporation is.
The containment area is purposely exhausted along the walls (rapidly drying them as well) to the rooms upper air levels.
The final procedure to prevent the upper air levels of the room from becoming too hot or too wet with humidity, is to set up thermostatically controlled evacuation fans to the outside. This can be complemented with dehumidifiers. There is seldom any reason to let the room exceed 95°F.
TES thermal energy system
This is the new patent-pending equipment necessary to apply the Reets Evaporation Method to drying.
The system incorporates a 199,999 thousand BTU boiler that super heats a unique freeze-proof liquid. The heated liquid is pumped through insulated hoses to the TEX (thermal exchanger) units, strategically placed in the water damaged area, effectively transferring the heat in the remaining water.
TES can be permanently mounted in/on a trailer, or installed with a wheel kit for portability. Made of stainless steel, it can operate in outside temperatures upwards of 130 degrees, or as low as 30 degrees below zero; without damage or corrosion.
The acronym of HAT is used for teaching drying – Humidity, Airflow and Temperature. These three elements make up what is called the drying pie. Increasing any of the “slices” would decrease the need for the others. The inverse would be true, as well.
Humidity and Airflow seem to get the most attention. Temperature control is usually limited to keeping the temperature in optimum range for dehumidifiers and the comfort of the occupants, but when properly applied, temperature, in the form of heat energy, can be a great help to drying.
Great advances have been made in recent years in drying equipment and methods, but there remains a bottleneck to our current drying systems. This bottleneck is evaporation. We have excellent equipment for removing water vapor from the air, but we have been limited in the ability to get the vapor into the air – evaporation. The surface water evaporates very quickly, but the water contained in the materials (hardwoods, carpet cushion, sub-floors, sill plates and wall boards) can take days to remove. If we could speed that process, we could speed the overall drying process.
How does evaporation work?
Water exists in three different phases – solid, liquid and vapor. What causes it to change from one phase to another? It is the addition of energy or heat. The phase change from liquid to vapor is our main concern and what we call evaporation.
Energy (heat) and airflow applied to directly to water (liquid) will speed the phase change to vapor causing evaporation. You have experienced this all your life. Here are two examples: One is a hair dryer – how can you step out of a long shower into a small room with water condensed on the all the surfaces, including the fogged mirror and even have visible vapor (steam), yet dry your hair with a hair dryer? Or why does it take water from an aquarium so long to evaporate, but a pot of water on a stove burner will evaporate very quickly? The answer is, of course, energy (heat).
Is there a way to gauge the evaporation potential of liquid in a material to see if the evaporation rate can be increased? Yes and here it is:
V is the vapor pressure of the air directly above the surface of which we are trying to remove the moisture. This is calculated by measuring the temperature and relative humidity.
E is the evaporation potential. The higher the evaporation potential (difference in the vapor pressure of the surface and the surrounding air), the faster the evaporation may happen as long as there are no barriers preventing vapor transfer.
Raising the temperature (applying energy or heat) to the surface will have a much greater effect on the evaporation potential then lowering the grains (vapor pressure) in the air.
If you want to dry structures faster; consider using energy (heat) to your drying process.