ABSOLUTLEY don't do this. your just going to cause the evaporator coil to freeze over and eventually burn up the compressor. it will also pull tons of amperage as the evap coil starts to freeze, at best that pops your breaker at worst it starts a fire. just put the ac in the window, set it to the temp you want, and you will be fine.
My dehumidifier does this regularly. Once the evaporator freezes it shuts the compressor off. There is a temp sensor on the evaporator. Once it is above the point they have set above freezing then it comes back on again.
dehumidifiers have auto defrost cycles because they are designed to be able to remove moisture down to lower temperatures near 40f ambient. air conditioners DO NOT have this feature and are not meant to freeze over. restricting the airflow out of the ac is absolutley not something you want to do ever, it will be hugely inefficient as well as eventually destroying the compressor.
More than likely my dehumidifier needs a charge or is over charge. It's a POS used Sandy Storm ebay special. I would really be surprised if there isn't some sort of protection on a window AC unit. We uses to use thin sheets of fiberglass matting over the front as filters at work..
like I said dehumidifiers have auto defrost so that they can still dehumidify down to roughly 40f ambient, at that temperature the evaporator temperature could be 20f and so moisture will freeze as it goes across the coil, therefore the dehumidifier has to be able to auto defrost the coil. like you said some models do this by shutting off the compressor and continuing to run the fan. A window air conditioner does not have this feature and will continue to run until either the breaker pops, the thermal overheat switch on the compressor trips(if it has one), or the compressor its self or some of the wiring burns up. hopefully the breaker will pop before the last one happens, but its not a given because window air conditioners are not usually run on their own circuit so the amperage of the breaker is usually much higher than the amperage the aircon will pull during normal operation, especially if its a smaller 5k or 7k btu model.
Like I said my POS dehumidifier does not and it is worthless below 70F. And like I said I would be surprised to see any AC unit without a temp sensor on the evap coil. How many are running right now with clogged up coils?
as far as carbon your lucky to live in Australia where all the good carbon come from so I bet its pretty cheap. I would go with a thick 2.5 inch layer of the pelletized carbon, CAN filters use a carbon called ckv-4, i think its a 4mm pellet and they use a 2.56 inch layer. the pelletized carbon allows more airflow so the depth can and should be thicker. 2" would work okay too though. I recommend the pelletized because it seems like the companies who use it basically just dump it in there and maybe shake it or something to get it settled, where as the companies that use 2" granular carbon seem to use some sort of machine to really pack it in there tightly and uniformly and I think that would be harder to do properly on a diy project. just my 2 cents, I am not in the carbon filter manufacturing biz but I have taken apart and repacked several filters of both kinds with fresh carbon and like I said, the ckv-4 is just settled in there nicely whereas the granular stuff is really jammed in there tightly and uniformly. I have also found the pelletized ckv-4 to last much longer, but seems to need a thicker bed depth to really work well. I have also noticed that the high end filters using pelletized carbon always have a thicker bed depth (like 2.5 -2.7 inches) whereas the granular stuff is usually thinner, like 2 inches maybe 1.8.
i already went with the non pelleted carbon lol, did not have the patience to wait for a answer, all the diy models i looked at online uses this type, going make the filter extra long for the needs of my flower room to be safe so i don't need so much static pressure from the exhaust to pull air from it, i think 50cm or 20in should be enough, going to do a test run and if needed be i will think about swapping for the pellets or using another equal exhaust inline to increase pressure, since they are not expensive, looks like a bathroom exhaust.
no worries man, granular should be fine. out of curiosity how expensive is carbon in aus? its pretty pricey here since it all gets imported from austraulia
I don't live in aus lol, i'm from Brazil
thanks for the tip, my unit has the option to drain the water or do what your have said, but for easy of mind going to sprays some air disinfectant now and them inside of it to kill any trace of mold.
i'm sure its not healthy, there's even a lung disease associated with miners that work on coal mines
C
www.mayoclinic.org