The energy efficient choice
All desiccant dehumidifiers operate on the same principle. Moist air
passes over a desiccant material, which grabs the moisture, releasing
dry air to be recirculated back into a room or building. The desiccant
is then heated to remove the moisture from the dehumidifier and the
moisture is then released outdoors.
The difference between desiccant dehumidifier designs is in the type of
desiccant used and the way in which it is introduced to the moist air.
Regardless of the design, natural gas desiccant dehumidification is an
energy-efficient way to keep large areas feeling dry and comfortable,
even on the hottest most humid days.
Desiccant dehumidification is ideal for buildings:
Which require low indoor humidity
at a dew point of 10 C or less.
Where the latent load is greater
than 25% of the total cooling load.
Which have a high fresh air intake
or are in humid climates.
Rotating dry desiccant wheels
Dry desiccants collect moisture on their surface and hold it, a process
known as adsorption, not absorption.
Some common dry desiccant materials are silica gel, titanium gel, dry
lithium chloride, natural zeolites and activated alumina.
Whatever type is used, it is formed into a wheel with a large surface
area. Moist air passes over the surface area and is dried by heating it.
A properly maintained desiccant wheel will last anywhere from 5 to 10
Liquid desiccant systems
Liquid desiccants work on the principle of chemical absorption of water
vapour from the air. The moisture is pulled out of the air and absorbed
by the liquid desiccant.
Over time, the water extracted from the air will dilute the liquid
desiccant. To maintain its prescribed concentration, the desiccant is
fed through a regenerator where it is heated to release the moisture.
The water is exhausted outdoors and the regenerated desiccant is cooled
Liquid systems are the ideal solution where biologically uncontaminated
air is required, in places such as healthcare facilities or sensitive
industrial applications such as pharmaceuticals. The liquid desiccant
kills bacteria on contact, and there are no cool surfaces on which
bacteria could grow.
Routine maintenance is required for either a dry or liquid desiccant
system. Air streams must be filtered, and filters should be checked
regularly to ensure they are clean.
In humid climates, it’s a good idea to mix incoming air with existing
air in the space being cooled to avoid introducing overly humid air into
the system. Mixing indoor and outdoor air in this way will keep indoor
humidity levels down.