(Supersedes ANSI/ASHRAE Standard 139-1998)

First published in 1998, ANSI/ASHRAE Standard 139
was developed under guidance from TC 8.12, Desiccant
Dehumidification Equipment and Components (previously TC
3.5). This intent of this standard is to provide uniform test
methods for rating desiccant dehumidifiers that utilize heat for
the regeneration process. It addresses the test methods, apparatus
and instruments to be used, data to be obtained, and calculations
needed to confirm valid test results.

This 2007 edition of the standard updates the original
publication by cleaning up the figures showing test loop configurations,
adding reference calculations to aid in troubleshooting
of mass balance results outside the acceptable
range, and making minor editorial revisions. All cited references
have been updated to the latest versions at the time of
publication.

1. PURPOSE
The purpose of this standard is to provide test methods for
determining the moisture removal capacity of heat-regenerated
desiccant dehumidifiers as well as the coincident thermal
energy performance so that comparative evaluations of capacity
and performance can be made irrespective of the type or
make of the device.

2. SCOPE
2.1 This standard applies to desiccant-based dehumidifiers
operating at atmospheric pressure. The dehumidifier may utilize
solid or liquid desiccants that are regenerated utilizing
heat energy.
2.2 Normally, equipment within this standard would consist
of one or more desiccant contact stations through which the
air to be dehumidified is moved, a means to expose the moisture-
laden desiccant to a source of heat energy for regeneration,
and a heating device.
2.3 Ancillary devices are normally utilized to move air to be
dehumidified through the device and to provide ventilation
for regeneration, but they are not a part of this standard.
2.4 This standard is intended to

1. describe a uniform method of testing for obtaining performance
   data,
2. describe and specify test instruments and apparatus,
3. describe and specify test data to be recorded, and
4. describe and specify calculations to be made from the test
   data.
   

2.5 This standard does not apply to:

1. dehumidifiers operating at other than atmospheric pressure,
2. dehumidifiers not utilizing a desiccant for dehumidification,
3. dehumidifiers not utilizing heat for regeneration of the
   desiccant, or
4. ancillary equipment that may be used in any dehumidification
   process such as fans or pre- or post-conditioningequipment.