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The Pros and Cons of UV and Corona Discharge Ozone Generators

by Dan Strickland on 10/07/2013

Whether for residential or commercial use, ozone generators are used to remove and control a variety of odors. But how do you harness its power into a usable generator? Well, for the uninitiated, ozone is basically three parts oxygen (O3) and, outside of lightning strikes or other natural phenomena, there are two main ways we generate ozone: ultraviolet rays (UV) and corona discharge (CD). What are the differences between the two? Is one likely to be better for your specific needs? To help you decide, below are some key points to consider.

How do each produce ozone?

UV ozone generation occurs when light is passed over a UV lamp, which splits oxygen molecules, allowing them to reattach into ozone, O3.

CD ozone generation is accomplished by passing air through an electrical field (varying from low, medium to high frequency) and the electric current is what splits the oxygen molecules, which then creates the ozone, O3. Most CD ozone generators also have some form of cooling mechanism, usually air or water, since the electric current also generates heat.

Pros and Cons of UV Ozone Generators

A UV ozone generator is easier to clean, doesn’t produce nitrogen oxides and isn’t affected by the presence of humidity in the air (its major upside).

There are, however, a few important disadvantages associated with UV generators. First off, they don’t produce a high concentration of ozone. As a result, air needs to be exposed to the UV lamps for a longer time, thus it costs more to operate and, overall, they’re not as efficient as a CD unit. The minimum ozone production rate also makes UV technology difficult for certain commercial uses, including large-scale water treatment.

Another disadvantage of the UV ozone generator is its UV bulb life expectancy. While the unit itself may be less expensive, the UV bulbs can require yearly replacement with continuous use. Bulb replacement combined with the additional energy required to operate the unit results in (significantly) higher operating costs.

Pros and Cons of CD Ozone Generators

These days, corona discharge generators are quite commonplace both commercial and residential settings. It’s the preferred technology due to its ability to create higher AND quicker concentrations of ozone…giving it a much more efficient profile. By weight, CD machines can produce about 90% higher concentrations of ozone than UV. Not surprisingly, it’s also more cost-effective since it requires less energy at every ozone concentration level. With regard to long-term costs, its corona cell plates last much longer UV bulbs — on average, most consumers get over 10 years of high-yield use per plate, depending on the model (see our top-ranked CD ozone units).

Another important feature of CD generators is their size — smaller parts allow for greater flexibility, both is use and installation. With regard to cleaning, you’ll want to clean your CD generator every couple months to keep it at max production (less frequently if you use pure oxygen or a heated air dryer).

The primary downside of CD generators is that ozone production is affected by humidity. Just as static electricity is impacted by humidity, corona discharge can begin to slow down at humidity levels exceeding 60%. So, if you’re inside on a humid day, run your AC or other dehumidifying measures to get it below 60% and all should be well. If that’s not feasible, just wait for a better day. In over 10 years in the business, humidity issues have affected less than 5% of our customers, so while it’s something to consider, the majority of folks don’t ever encounter any humidity problems.

Bottom Line

Years ago, we had a decision to make — corona or UV. After running a variety of production (and cost) tests, it became increasingly clear CD was the way to go. From higher efficiency to longer shelf lives, we now recommend corona discharge units for all broad or specific applications, both commercial and personal. If you have any questions regarding CD vs UV, feel free to get in touch.

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