07-00283 C 12-02 Copyright 1999, Dri-Eaz Products, Inc.
4
Here is a quick review of the operation:
1. Moist process air is drawn into inlet and through the de-
humidifier.
2. Moisture in the process air is captured on the desiccant
rotor and the dry process air is vented through process
outlets back into the room.
3. Reactivation air is heated within the dehumidifier.
4. The wet area of the rotor turns into the reactivation sec-
tor.
5. The moisture in the desiccant rotor is released into the
heated reactivation air.
6. The reactivation air, laden with moisture, is vented
through the reactivation outlet to the outdoors.
7. The reactivated rotor rotates into position to capture
more moisture.
OPERATING CONDITIONS
The DriTec Desiccant Dehumidifier effectively removes
moisture at virtually any job temperature without the freeze-
up problems associated with refrigerant dehumidifiers. Low-
temperature operation is one advantage of using desiccant
technology.
The DriTec dramatically reduces ambient humidity to
very low levels not obtainable with refrigerant dehumidifi-
ers. This allows faster and more thorough drying of dense
materials like hardwood flooring and structural woods.
The DriTec also uses improved technology that removes
humidity When a desiccant dehumidifier is first put into
operation in a saturated environment, it will constantly re-
duce humidity. Its rate of water removal is determined by the
volume of the area, the environmental conditions, and the
capabilities of the machine.
Saturated Environments
On many restorative drying jobs, the initial humidity is
very high as porous materials like carpet and cushion give
up moisture to the air. However, as the job progresses and
humidity levels fall, moisture may need to be evaporated
from less porous materials including drywall and wood.
Refrigerants are most effective when both humidity and
temperature are high. They are much less effective in ambi-
ent conditions under 50% relative humidity or 50°F (10°C).
Desiccant dehumidifiers are generally effective in all ranges
of temperature and humidity.
In saturated environments it is often helpful to use the
DriTec Desiccant together with refrigerant units to speed the
drying process. In these conditions the DriTec removes wa-
ter as well as a comparable refrigerant unit. Also, it is actual-
ly more cost effective. (For example, a 25-gallon/day
refrigerant dehumidifier that costs $2,195 removes water at
$87.80 per gallon. The 48-gallon/day DriTec 325 that costs
$3,699 is removing water at $77.06 – a cost savings of over
$10/gallon.)
Lower Levels of Humidity
When the relative humidity falls to 40%, a refrigerant
dehumidifier will remove little additional water. At this
point many materials in the room such as carpets and wall
surfaces may feel dry, but moisture may remain in structural
materials. Ceilings, walls, and structural flooring materials
typically take longer to dry. The DriTec Desiccant is superi-
or for drying these materials. It has the capability to lower
humidity over time to below 1% Rh. The low humidity envi-
ronment created by the DriTec speeds the drying of structur-
al materials which dry very slowly in conditions of normal,
comfortable humidity.
The DriTec Desiccant also can be more cost-effective
than refrigerant dehumidifiers in low-temperature condi-
tions. The DriTec continues to remove moisture at tempera-
tures down to freezing, so it may be effective even in
unheated buildings.
Monitoring Specific Humidity Changes
For fast and complete drying, the specific humidity in the
area being dried should be monitored. Specific humidity
measurements can be obtained using a thermo-hygrometer
(such as the DHT 600) to obtain relative humidity and tem-
perature of the ambient air, plus a Psychrometric Calculator
or Chart.
Specific humidity readings (measured in grains per
pound) give a true indication of the amount of moisture in
the air. Relative humidity readings alone is not useful infor-
mation unless the temperature is always the same, wherever
and whenever a measurement is taken. This is seldom or
never the case in water damage restoration.
Moisture Content of Materials
The moisture content of structural materials should also
be monitored with a moisture meter such as the MoisturePro.
A moisture meter indicates the extent that these materials are
wet. It will assist you, and your customer, in determining
when the job is completely finished. A variety of moisture
meters are available from Dri-Eaz Products.
MAIN COMPONENTS
Figure 1 shows most of the important parts of the DriTec
Desiccant Dehumidifier: the rotor, process air stream, and
reactivation air stream. The DriTec Desiccant has seals sepa-
rating the two streams of air – the damp process air, and the
heated reactivation air. Notice that the two air streams move
through the DriTec Desiccant in opposite directions.
Air Filter
If the air in the room is dirty, the dirt can collect in and
plug the passages of the rotor. A cleanable foam air filter is
placed on the intake side of the rotor to catch dirt in the air
stream.
Process Air Outlets
Process air is vented from the DriTec through one or two
outlets, one of which is adjustable with a slide lever.
Reactivation Air Stream
The reactivation air stream uses approximately one-third
of the total air stream, which flows through electrical heating
elements and then through the rotor, where the heat reac-
tivates the desiccant. The air stream then passes through the
reactivation outlet and is vented through ducting to the out-
doors.
