Re: Re: Copper in HVAC Coils - Why electrostatic fails for mold

[Guest guest]

I'll add my three cents worth. I agreed with the entire thread, and in the

areas where I have researched I supplement, or amend the posted info.

At 07:12 AM 7/26/2009, you wrote:

> Don't be fooled by claims of treated, washable, electrostatic or

> electronic filters.

Electrostatic filters let through 3 types of substances.

1) Ultra light molecules that when approaching the charged surface of the metal

inside the filter will see a " mirror image " of their acquired

negative charge, and

due to the lightness of the molecule, this mirror image will " repel " the light

molecule, reversing it's movement towards the metal grill surface, or at least

slowing it down, so it " escapes " adhering to the filter material, and

gets through

the electrostatic filter material, and enters your breathing air.

2) Ultra heavy substances, like mold spores, can go through, for some acquire

the negative charge in the first section of the electrostatic filter,

but then due

to the inertia/weight of the heavy particle, the second section of

the electrostatic

filter, that should attract the heavy particle, pulls the charged

heavy particle towards

it, but due to the weight of the particle, it accelerates slowly, and

'escapes' touching

the grounding surface, and leaves the filter, to enter your breathing air.

3) Particles of any size or weight, that can change it's electrical

dipole moment,

thus, neutralizing most of the effect of acquiring a negative charge,

as the dipole

moment rotates to then neutralize the second stage filter. Most mold spores

can change their dipole moment. Ok, that is dipole? Imagine a stick with

two balls, one at each of the ends of the stick. One ball gets

negatively charged,

acquires an negative electron from the first electrostatic filter

stage, so the other

ball is now relatively positively charged. As this " stick " goes

through the second

filter, where this dipole particle ought to be captured, one ball is

attracted to the

metal filter material, while the other one is repelled. This rotates

the dipole,

and due to inertia, the positive charged end is now pointing towards the metal

grounding surface, and as this surface is positive charged, to attract negative

electrons on particles, the second positive charged ball is 'repelled' as like

charges repel. This again rotates the dipole, or rather encourages it to

keep turning, or even accelerates the rotation, so now the negative end is

facing the metal filter, and is attracted, but the rotation,... so on

and so on.

And it escapes the filter. Another way the dipole particle escapes is it

adjusts the charge from one ball to another ball, changing it's motion

through the filter, and escapes the filter.

So, electrostatic filters, of all sorts, except those designed with these

3 variations in mind, meaning not 6 inch thick second stage, and not

fast moving air, but slow moving air, or thicker filters, 8 to 12 inch, or

double second stages, or both, will capture " more " , but not all.

Thus, HEPA filter technology will catch all but the ultra light molecule

that can be smaller in physical size, and get through the HEPA material,

as it is smaller than the pore size.

>Disposable, pleated media filters are the answer for central

>systems, the deeper the better.

Hmm. Yes, but also, stranded media 2-3 feet thick, along the air

path flow, will do the same,

if not better, and last longer, 6 to 12 months, or even longer,

before replacement is needed.

Imagine your filter being in a cardboard box that is 3 feet long, and

2 feet wide and deep.

Two opposite ends of the box are open, for air flow in and out. And

the box is filled with

strands of inert glass, fiberglass, packed tight enough so that 0.3

micron particles are

filtered out. Millions of such fibers all running along the air flow

direction. Industrial grade

for central AC units. It's big. It requires lots of space to

install, which many houses

do not have in the attic. And the motor of the AC unit needs to be upgraded to

force air through such a resistant filter. It will cost several

thousand dollars.

The one condo I have seen this in, the air inside was wonderful.

>For window and wall A/Cs, pleated media filters are not available

>and you must use foam-type pad filters (such as Web Products).

Or make an adapter out of aluminum foil and 2 " packing tape, using

blue painter's tape

to tape the filter onto the adapter. Not for everyone. I've used

cardboard to stiffen as well.

And made a wood frame to hold the pleated filter twice.

>Although high-energy, UV-lamp arrays can be effective in commercial

>installations, typical, single-bulb UV lamps for homeoowner systems

>are useless.

The air flow past a single bulb is so fast, and 3-6 seconds are

needed to kill 80% or more

of the germs, rupture their cell membrane from heating, or destroy

DNA in their nucleus,

or other method, that one has to have a " long " bulb and " slow " air

flow, to get a kill

rate of 100%, meaning the physical size of the unit is now 8 feet long or more,

or has a complex folded air pathway, and clear to UV rays walls, so one light

bulb's UV rays pass through all tunnels of the folded air pathway. No one has

designed such. There are less than a handful of effective UV light systems

for household use, both free standing and central. The free standing ones

have low air flow.

The central ones have 6 or 8 foot bulbs that must be

mounted inside an all metal air duct, with both ends having end caps,

or corners the air must bend through, so no UV rays escape to strike

your eyeball cornea and cause cataracts, a clouding of the lens, and

thus blurred vision, which can then degrade, by itself, to legal blindness,

or even full blindness, which might or might not be correctable with

surgery, full cornea replacement, which might or might not last,

and might cause the immune system to rejection of the entire eyeball,

which would have to be removed.

Yes, UV is dangerous to the eyes. Not for a novice to make without first

researching all the safety needs. Even some professional units I have

seen allow 'reflected' light of the bulb, to be seen, blue light,

with the claim

that the UV was not reflected. Sure, 60% not reflected? 80% 90%?

I'm a physicist, and I know that some low percentage of UV will be

reflected. In my opinion, 0% UV indoors is the right amount.

Outdoors with no ozone layer to block UV is worse enough.

The eye should have a chance to heal, during it's indoor time.

>Some of you may be interested in the PDF of the presentation I gave

>at the National Air Filter Association (lots of photos!), accessible

>from the home page at <www.mayindoorair.com>.

Thanks Jeff.

Pete

> May

>May Indoor Air Investigations LLC

>www.myhouseiskillingme.com