1) REFRIGERANTS
2) DESICCANTS

1) REFRIGERANTS
Refrigerant dehumidifiers work by drawing "wet" air across cold condensation coils turning the vapor into a liquid and, therefore, removing it from the air. These machines will work only in a temperature range of 70 to 90 degrees fahrenheit.

There Are Three Types of Refrigerant Dehumidifiers:

A) Standard (No Defrost Cycle)
B) Conventional (Hot Gas Bypass - Defrost)
C) LGR - Low Grain Refrigerant

A/B) Standard and Conventional Dehumidifiers are basically the same machines with one exception: Conventional dehumidifiers have a defrost cycle which keeps the machine's condensation coils from staying "iced up."

They will both only work between the temperature range of 70 - 90 degrees, however, so even though the conventional dehumidifier will "defrost" it is still not pulling any significant amounts of water from the air.

These machines will pull the grains of moisture (GPP, or Specific Humidity) in the affected environment down to 55 to 60 GPP.

Standard or Conventional dehumidifiers will pull 2-3 pints of water per KW of electricity

C) Low Grain Refrigerant (LGR) Dehumidifiers work differently. They still work on the principle of condensation, but have a separate piece added to them which pre-cools the air before it passes over the condensation coils.

Because of this design difference, LGR's can remove much more water vapor from the air.

These machines can pull the grains of moisture (GPP or Specific Humidity) in the affected environment down to 32-35 GPP.

In the LGR family, there are two different designs which accomplish the task of pre-cooling the air:

1. The "Recuperative" design (The Phoenix 200 & 300), and the
2. "Heat Pipe" design (The Dri-Eaz 2000 & 2400).

Of these two, the recuperative design is the more efficient, pulling 5 to 7 pints of water for every KW of electricity, where the heat pipe design will pull only 3 to 5 pints per KW.

The LGR is by far the most efficient dehumidifier on the market today, and though they cost more, will dry structures in half the time of standard or conventional dehumidifiers.

WHEN USING A REFRIGERANT DEHUMIDIFIER, YOUR CONTRACTOR SHOULD ONLY BE USING LGR's!

2) DESICCANTS

Desiccants dehumidify air differently. Instead of using condensation coils to turn vapor into liquid, a silica gel or a similar substance is used to remove the water vapor from the air.

Desiccants work by blowing the wet air across the absorbing material, then use extremely high temperatures to "bake off" the moisture and exhaust the "wet" air out of the machine through a duct to the outside of the structure.

Desiccants can bring the grains of moisture (GPP or Specific Humidity) inside the affected environment down to 10-15 GPP.

The low GPP produced by a Desiccant DH is preferred in specialty drying situations where moisture will not come out of the building materials easily.