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A Different Technology - Polarizing
vs. Ionizing
Polarization
is very different from ionization,” explains
Duke Wiser, president of Dynamic Air Quality Solutions,
the leader in manufacturing products using
polarized-media technology. “A polarized field does
not produce any ozone, which occurs with ionizing. And
polarized molecules are not charged and therefore less
apt to collect where you don’t want them to. By
contrast, ionized particles have either a positive or
negative charge and are attracted to oppositely charged
surfaces such as collector plates in precipitating air
cleaners. But charged particles can also collect on
walls, ductwork, and clothes.
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Polarized particles
are bi-polar which means that each
molecule charge (at one end) and a
negative charge (at the other end).
Polarized particles are
attracted to the other polarized
particles that tend to float free and
are recirculated through an HVAC system.
Polarizing produces
no Ozone.
Polarized media air
cleaners increase in efficiency as the
media loads.
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Ionized particles
are either positively charged or
negatively charged. An ionized
particle is attracted to an
oppositely charged surface such as a
collector plate and precipitating air
cleaner.
Ionizing can produce
Ozone as a by-product.
Precipitating air cleaners lose
efficiency as Ionizing
wires and collecting plate surfaces get
dirty.
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Table: Polarizing vs. Ionizing
Polarized-media air
cleaners do an excellent job of removing sub-micron
(less than 1 micron in size) particles and without the
efficiency loss associated with precipitating electronic
air cleaners. The carbon center screens that are used in
Dynamic air cleaners also trap odors and volatile
organic compounds (VOCs). By the nature of polarization
technology, the air cleaner’s effectiveness is best
measured by assessing particle levels in the home or
building over time. Part of the reason for this is a
process called agglomeration. Trapped particles
become polarized, as do any particles that pass through
the air cleaner. Through agglomeration, the polarized
particles bond with other polarized particles as they
collide in the air. As they increase in size, they are
collected. This enables the air cleaner to capture even
the very smallest sub-micron particles that tend to
suspend in the air rather than move in the air stream.
“Any air cleaning
system’s effectiveness will be, in part, determined by
the air change rates, airflow patterns, and contaminant
generation rates,” continues Wiser. “Typically in a
house we see particle reductions of 70-90%, but because
of the low air change rates in a home, it may take a few
days. In a casino, on the other hand, even though the
contaminant level and generation rates are much higher,
the air change rates are over ten times higher than in a
house, so significant reductions in both particles and
VOCs are almost immediate.”
Laser particle counters
confirm this phenomenon. Over a time period of several
days you will first see a reduction in particles under
.3 microns in size. At the same time there is a spike in
the number of larger particles as the smaller particles
form larger particles, and then the total particle count
drops off significantly.
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Media Technology |
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Testing and Performance
Since passive
filters are the most widely used technology,
passive filter tests tend to dominate the test
standards. MERV (minimum efficiency reporting
value) is the most commonly used measurement for
filters. MERV is based on a single pass and is
used for measuring passive mechanical filters.
“This is the biggest challenge for
manufacturers of polarized-media air
cleaners,” Wiser explained, “there is no
widely-accepted test protocol today that
demonstrates the effectiveness of
polarized-media.” Wiser continued,
“Single-pass measurements don’t account for
loading which is the trade-off for efficiency.
For mechanical filters, loading is detrimental
because it increases static pressure. And
although static pressure is not an issue for
electronic precipitating air cleaners, they lose
efficiency as plates and wires get dirty. So
ratings like MERV do not provide a universal
indication of performance under real-world
conditions.”
Filter
Pressure Drop vs Dust Load
SAE Fine Dust

Filters
with an applied electric field, such as a
polarized-media electronic air cleaners, have a
lower pressure drop than the filter without an
electrical charge giving it a longer service
life than standard filters.
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| Polarized
Media Technology |
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Benefits of Polarized-Media
Air Cleaners
Performance
aside, within the residential segment, air
cleaner size is the biggest benefit.
Polarized-media air cleaners represent the only
high-performance air cleaner option that can be
installed with minimal labor and no ductwork
modifications. This makes it a candidate for
sale on any service call, repair call or
maintenance call. This is a big exception to the
traditional thinking that implies that the
logical time to sell an air cleaner is when the
indoor unit is changed out.
Commercially,
again with efficiency aside, the biggest benefit
is the payback based on energy and operational
cost savings. There are many costs associated
with commercial filters. The lower static
pressure of polarized-media air cleaners means
lower energy consumption. There are also costs
associated with shipping, storing and replacing
large, bulky filters. Polarized-media load more
efficiently which translates to longer
maintenance intervals which save time and labor.
The combined effect results in operational costs
that can be a fraction of traditional
alternatives. “Casinos were early adopters
because of the products effectiveness at
removing tobacco smoke and odors, and casinos
ability to correlate air quality to revenue,”
Wiser explained. “Other recent high-profile
projects include the U.S. Securities and
Exchange Commission and Churchill Downs.”
The technology
has been an important part of indoor air quality
programs for contractors and engineers that are
responding to the heightened consumer awareness
about IAQ. “We estimate that polarized-media
sales account for 15-20% of the current
electronic air cleaner market,” according to
Wiser. “And that share is growing. There are a
lot of products in the burgeoning IAQ market.
Polarized-media electronic air cleaners are a
great value. And in the end, it’s all about
value.”
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