Sterling ERMS - Manual (Page 12)

© 2005 Airxchange Inc. All Rights Reserved
Cleaning Airxchange Wheels
and the ability to soak the individual segments clean
so that the need for cleaning is less frequent.
An alternate to cleaning is the periodic replacement
of dirty segments. This can be economically
advantageous when both labor costs and energy
costs are rising.
Recommended Cleaning Procedure
Access the energy recovery wheel and remove the
energy transfer matrix segments. (For one-piece
wheels 25 inches in diameter and smaller, remove
the wheel from the cassette.) First brush the wheel
face to remove loose accumulated dirt.
Wash the segments or small wheels with a non-acid
based (evaporator) coil cleaner or alkaline detergent
solution. Non-acid based coil cleaner such as KMP
Acti-Clean AK-1 concentrate in a 5% solution has
been demonstrated to provide excellent results. Do
not use acid based cleaners, aromatic solvents,
temperatures in excess of 170
O
F or steam;
damage to the wheel may result. Soak in the
cleaning solution until grease and tar deposits are
loosened. An overnight soak may be required to
adequately loosen heavy deposits of tar and oil
based contaminants.
Internal heat exchange surfaces may be examined
by separating the polymer strips by hand. (Note:
some staining of the desiccant may remain and is not
harmful to performance.) After soaking, rinse the
dirty solution from the wheel until the water runs
clear. Allow excess water to drain prior to replacing
segments in the wheel or reinstalling the wheel in the
cassette. A small amount of water remaining in the
wheel will be dried out by the airflow.
Last Reviewed 6/28/06
Overview
All air-to-air energy recovery devices will get dirty
over time, even with well-maintained filtration. One
advantage Rotary wheel technology has over fixed
exchangers is the ability to ‘self clean’ of dry dust and
dirt by rotating between two opposing airstreams
traveling from 500-800 fpm. In wheels with laminar
flow matrix designs, this self-cleaning feature works
well until the wheel is exposed to oils, tars or greases
in either the supply or exhaust air streams. Once
these pollutants deposit on the rotary surface they
become ‘sticky’ and begin to attract and hold the dust
particles that previously passed thru the wheel. Over
time this particle build up can lead to blocked airflow
passages, loss of recovery, excessive pressure drop
through the wheel and loss of energy savings.
Field experience shows that offices, schools and
other ‘clean’ environments will often go 10 years
before any build up of dust and dirt is noticed.
Restaurants, Casinos, factory environments
experience fairly rapid build up of contaminants and
require multiple cleanings a year to maintain airflow
and recovery.
Field experience also shows that all rotary wheels will
experience some degradation of latent recovery, long
before they appear to be plugged. While exhaust air
contamination is the primary source, local
environmental conditions can contribute. For
example units located near heavily traveled
expressways or downwind of fast food restaurants
may experience measurable loss of latent
performance within 3-5 years of operation.
Airxchange wheels are manufactured to be easily
cleaned outside of the unit. The benefits include
elimination of a drain pan in the wheel section of the
unit and associated IAQ problems, the elimination of
the need to drag a pressure hose to the unit on a roof
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