One Engineer's Opinion graphic

Needlepoint Bi-Polar Ionization Just Gets Better and Better

March 12, 2019

The manufacturers of needlepoint ionization products are continuing to make improvements to help the end user. Some examples are: Almost no size restriction: A single power supply can serve six 12 foot long bars.

Bruce Longino, PE, LEED AP
Bruce Longino, PE, LEED AP

This can cover a 150,000 CFM Air Handler. The ions shoot out of the recessed carbon fiber brushes spaced a ½ inch on centers, so fast that they will cover cooling coils up to 60 inches in height, before being drawn through the coil.

As the ions are drawn through the coil they keep the coil clean by killing mold, bacteria and viruses. This eliminates the yearly steam cleaning of the cooling coil and drain pan.

This is better than the use of UV lamps, because it cleans the inside fins of the coil, even on the deepest coils. UV lamps only clean the surface of the coil and a short distance into the coil.

The ions then travel through the duct system helping it stay clean as well. Then the real magic happens when the ions enter the building. The ions kill mold, bacteria and viruses in the building air and on building surfaces. I know from personal experience that this helps prevent the spread of illness like the flu. This product was installed in a Salvation Army homeless shelter in downtown Atlanta nine months ago. When flu season came around, the lady that runs the shelter said that in the past everyone got the flu because of the tight living conditions for 340 homeless people. She said after the ionization was installed, there were only a couple of cases.

Additionally, the ions remove harmful small particles from the air. Most buildings and homes have particles that are too small to precipitate out of the air to be vacuumed or moped up. These particles are also too small for the filter to remove. The positive and negative ions charge the small particles in the air and this causes the particles to agglomerate; this is a fancy name for clumping together. The larger particles are either moped, vacuumed or filtered out of the space.

Another wonderful thing these ions do is remove odors and volatile organic compounds from the building. I have personally witnessed the reduction of sewer gas smell, dumpster odor and cigarette odor. An easy example of how this works is how ions remove ammonia odor from a building. Ions are atoms or molecules with one too many or one too few electrons. The ions we are talking about occur in nature in the mountains or at the sea shore. Because of excess solar radiation and wave action H2O splits into +H and -OH. They are called “nature’s sanitizers.”

The -OH ion pulls the three H off of the NH3 ammonia molecule to make water.

The remaining N finds another and forms N2. So something that smells terrible becomes by-products that have no odor and that are already prevalent in the air.

Here is the modular, magic bar:One Engineer's Opinion - figure 1

Automatic Cleaning

In direct current (DC) needlepoint bi-polar ionization systems, carbon fiber brushes are charged with high voltage, and they attract dust since each brush cluster remains the same polarity. In alternating current (AC) systems, each brush cluster changes polarity, so what may stick on one cycle, repels on the next. As dust builds up on the brush tips, the ion density reduces.

To prevent this from occurring, the manufacturer developed an Automatic Cleaning process for their DC systems. This process uses a wiper blade to periodically engage and flick the dust off the brush tips. Even though the ionization generation products are designed to be installed after the HVAC filter, some dust does get through. Depending on how much gets through, the frequency of wiping is adjustable. Because there is some concern that the cleaning process may cause physical fatigue to the carbon fiber brushes, they are replaceable; however, life cycle testing shows no degradation. Here is what the self-cleaning system looks like:One Engineer's Opinion figure 2

Universal Voltage Input

Because it is sometimes difficult to determine the voltage that is available before the needlepoint product is shipped, the manufacturer made the product capable of using any voltage from 24 volts to 240 volts, AC or DC. The built-in circuitry ascertains the incoming voltage and sets itself to that voltage. Also, the power requirements are so small, typically the unit can be powered from the control circuit. As an example, the largest needlepoint bar product only requires 15 watts. To put that in perspective at 24 volts, that is only .6 amps.

Mounting with Rare Earth Magnets

When contractors are working around cooling coils with refrigerant or water under pressure, using screws can be a problem. Also, in tight spaces, getting power tools in place to do their job can be a problem. To solve this problem, the manufacturer ships rare earth magnets to mount the ion generators. To put the strength of these magnets in prospective, one attached to a flat surface can hold 60 pounds. Mounting of a needlepoint ionization unit to a supply fan inlet looks like this:One Engineer's Oopinion figure 3

Needlepoint Bi-Polar Ionization is Not Corona Discharge Ionization!

In December 2018, the ASHRAE Journal published an article on the changes in IAQ caused by corona discharge air cleaners. By publishing the article, the ASHRAE Journal created doubt in the mind of market as to the efficacy of Needle Point Bipolar Ionization (NBPI) technology for use in indoor air purification. They carelessly lumped NPBI with corona discharge ionization products, which are known to create ozone and undesired byproducts. They wrote “Corona discharge (sometime labeled: ionizing, negative ion, bipolar ionizing, activated oxygen, mountain fresh air, etc.), whereby associating NPBI with corona discharge.

NPBI technology is not corona discharge ionization. NPBI does not produce ozone or other harmful byproducts and the company providing the pictures for this article is certified by UL 2998 and UL 867 as an ozone and byproduct free technology. NPBI has been used for particle reduction, odor control, pathogen control and static electricity control for more than 10 years. The production of unwanted byproducts, including ozone, associated with corona discharge ionization air cleaners are avoided when using NPBI. The newer NPBI technology should NOT be associated with corona discharge ionization. This should be made clear to all, especially the readers of the ASHRAE Journal. The ASHRAE Journal’s peer review process clearly failed for this article and experts in the ionization industry were apparently not consulted prior to publishing.