Laclede Gas

Desiccant Dehumidification

Gas-Fired Desiccant systems are used as part of a cooling system to dehumidify, thereby separating the latent load from the sensible load. This separation results into the following benefits:

Individual control over temperature and humidity for greatest comfort.

Elimination of condensation on cooling coils and drip pans. Improving indoor air quality by reducing mold growth, mildew, and bacteria.

Lower humidity levels allow equivalent comfort levels at higher space temperatures resulting in energy savings.

Ability to decrease the size of cooling towers, associated piping system, and chillers.

Drier air can extend or increase the capacity of the existing chilled water units when cooling load increases.

Efficiently handles increased air volumes required by ASHRAE 62-89.

There are basically two types of desiccant systems used: liquid and dry wheel. The liquid system sprays desiccant liquid into the air stream, which removes the moisture from the air. This system is usually found in large industrial applications or microorganism sensitive processes. In the dry wheel system the air stream flows over a desiccant material which is usually embedded on a honeycomb wheel. This system is usually found in commercial and light industrial applications.

The operation of a solid based desiccant unit is as follows: Make-up or return air is passed through the desiccant wheel where the moisture in the air is removed. The wheel is constantly rotating to provide a dry surface area and to expose the wet desiccant to a regenerative (reactivation) air stream.

Typically, a direct-fired natural gas burner heats the regenerative air stream or the air is passed over a hot water/steam coil connected to a gas boiler. The regenerative (reactivation) air can be either exhaust air or outside air. After the regenerative (reactivation) air passes through the desiccant wheel and absorbs the moisture out of the desiccant it is exhausted outside. The dry supply air can then be cooled, if required, with evaporative cooling or a cooling coil before being released into the space.

Several successful installations are located in the St. Louis region.

Recent installations of desiccant systems include:

St. Louis Blues Practice Facility at St. Louis Mills
Schnucks Markets
Wal-Mart Stores
Webster Groves Ice Rink

Desiccant dehumidification has been specifically engineered for several applications, such as:

Supermarkets
Theaters
Ice Rinks
Hospitals/Surgical Suites
Office Buildings
Cold Storage
Restaurants
Museums and Libraries
Research Laboratories

Desiccant Unit Capacity

Process Airflow: 300 to 80,000 cfm
Moisture Removal Rates: 8 to over 3,400 lbs./hr

Estimation Figures:

Process Air Flow
Dry 35 cfm per lbs/hr removal
Liquid 20 cfm per lbs/hr removal
Regeneration Gas Consumption
Dry 2.5 cfh per lbs/hr removal

Options are available and vary by manufacturer:

Typical options include:

Pre- and Post-Cooling and/or Heating
Make-Up Air Heat Recovery
HEPA Filtration
Post Humidification
Power Dampers
Security Bars and Custom Roof Curbs

For additional information on desiccants, see listed sites:

The various links to other web sites that are included in this web site are not intended to be endorsements of such other web sites or the contents of such other web sites. Rather, these links are provided only as a convenience to the user. As always, the user should independently verify any and all information obtained from the internet.

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Desiccant Dehumidification

Recent installations of desiccant systems include:

Desiccant dehumidification has been specifically engineered for several applications, such as:

Desiccant Unit Capacity

Estimation Figures:

Options are available and vary by manufacturer:

For additional information on desiccants, see listed sites:

Organization Links:

Equipment Manufacturers:

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