I don't really know enough about air conditioning systems to...

I don't really know enough about air conditioning systems to pass a judgement, however if the application relates to the sanitation of systems with regard to legionaries disease etc rather than COVID then yes it has a lot of potential.
I don't think the way it has been described if the target is COVID it has any potential.

Planes for example use filters on their air conditioning systems that can remove COVID from circulating around planes, no need for an additional treatment.
If COVID in air conditioning systems was huge issue that wasn't already solved yes great but I don't think there is a requirement.

You can have the greatest product in the world techonology wise but if there is no demand it's worthless, not that I'm saying ZNO techonology is worthless.

IMO it's about finding an application that only ZNO can solve or at the very least solve far better, cheaper & more economical than anything else.

The biggest issue IMO with general surface sanitation is that it still needs to be cleaned daily etc for food/drink spillage, bodily fluids etc as well as microbes.
Why use something that lasts for 30 days, that is considerably more expensive, when you're also using a product daily anyway that does the same thing at a fraction of the cost?
Yes you get protection between daily cleaning but is the additional cost worth it when COVID is spread predominantly via air particles & rarely via surface contamination?
OK you have the chemical free bonus but IMO companies still care more about the bottom line than the environment & the price of ZNO products are too high for mass use.

IMO ZNO would be far better off partnering with an existing global brand to incorporate into an existing product range selling tens of millions of litres a year at $5 per litre than trying to sell to end customers at 8 times the price.