HVAC Master Class in Chemistry: Atila Novoselac on Ozone, CO2, Particle Filtration and Black Goo 

This is great. Love these deep dives.

My eyes glazed over a few times during the video, but I got the gist that AC has a number of inherent issues that are challenging to solve. Thanks for attempting to make the presentation understandable to us non-scientists. So glad I’m building my new house in a moderate climate that does not require any mechanical cooling!

I can't say much about Mitsubishi, but the Trane variable speed air handler/compressor will reduce the fan speed and compressor speed if the humidity is above the setpoint. I know Trane and Mitsubishi work together, but I'm not clear how much they with together. But, I don't know how long the air handler will run after the compressor runs. But, the Trane variable speed compressor can run at lower speed than the Carrier which operates the other half of the house. The Trane is definitely more efficient at reducing humidity, but e can't say which is better at removing other chemicals.

Very useful commentary, Corbett. Thanks!

ramping down, inverter heat pumps (at least the ones i know) do that. for eg mine here start ramping down once they get within 2c of target temp. also with the fan (if on auto). obviously they will run constantly at the lower speed if the don't hit the set point. a lot of these units use DC motors (for efficiency) and they tend to struggle with torque outputs at low rpm. so they don't go to very low rpm which you can do with an ac vfd/vsd.

Corbett, this was fantastic! Your explanations made it do much more applicable

Hi Corbett! I have a few questions about the video: 1. By what approximate percentage would the indoor particulate matter concentrations have fallen if the range hood fan would have been running during the toaster and cooking tests? 2. How much further would the particulate matter concentrations have fallen if a make-up air system had also been present in the kitchen and turned on when the range hood was on? 3. Where in the shown plan would you have placed the make-up air supply grills and how much air would each one of them supply (I’m guessing there would be more than one supply duct)? Are these questions answered in a later video?

Great video! 14:00 - also, ductwork especially flex ducts, positively charge those particles which may help this issue.

seems like best, for controlling both humidity and contaminates, would be running both FAN and COIL at 100% duty cycle, with cooling capacity control by variable refrigerant flow.

3:58 I think you meant to link to the thanksgiving day video Thanks for the series and deep dives

so fan on or auto?

No clue what I’m talking about here. Is this an argument for separating ventilation from heating and cooling or adding dehumidification after the coil? Proper filtration always seems a good idea. I think we still rely on gravity to remove moisture from the coil, which seems a bit archaic; is there a more rapid and efficient approach to removing moisture from the coil? Is there a coating that can be applied to the interior of ducts that would make them less able to hold moisture?

I just emailed my Mitsubishi rep to find out if we can program the system or thermostat to shut off the fan motor for a few minutes to let the indoor coil drain. I'll let you know what I find out.

If you have a insulated roof could you use a mini split in the attic to stop the vapor drive problem?

What about a UV light for water filtration?