Morphing Air Conditioner into Autocascade System

[n00b 0f l337]

Nah, it condenses very easily and in quantity, this helps give off heat in the condenser, and serves as a big sponge for other refrigerants to seep into.

[mytekcontrols]

Also what is your static now?

I hooked up a standard recovery tank to it before I it shut-down yesterday, and today the static BP = 55 psig.

Edit: My target static BP would probably be to keep it at 125 psig or lower (need to test maximum safe start-up abilities of compressor). So I'll need to calculate the tank requirements based on the present volume (inclusive of the added recovery tank), allowing for a BP at least 2.25 x the current pressure.

Oh really? Ah well crap, I'm plumbed that way thinking then liquid won't flood back as easily.

I'm not saying that it wont work upside down, but it depends to a large degree on the volume of your suction side, as well as the size of your compressor. However in an ideal design you do want to pay attention to this, especially if you are using your 1st phase separator to do most of your oil return (as I am).

I understand that, but how does lower the condenser's temperature ? The R-600 isn't evaporating in the condenser ??

Just like Nol said, it acts like a sponge for other refrigerants to dissolve into. Predominately this would be the R-170 in the system. When this is later evaporated, it'll do so at a temperature somewhere between R-600 and R-170. Think of what happens when you mix refrigerants to create something with a unique boiling point, same as what is done for R-410A a substitute for R-22. It also seems to have the added affect of enhancing the heat exchange in the air cooled condenser, think of it as a liquid heat sink in this case.

Edit: It also evaporates within the compressor, pulling heat out as it travels to the condenser.

Firstly how does the efficiency of this autocascade compare to a well build standard cascade, at the same loading / temperature tuning ? (Heat moved Vs Compressor power.)

I think the best way to answer this would be to have some of the standard cascade builders chime in, on how many total compressor amps it would take to duplicate the performance I am seeing with only 3.7 amps. Also I only have 1 fan, whereas a cascade would probably have at least 2 fans (or a single larger one being shared by multiple condensers). the additional or larger fan would also contribute to the amount of amps required to run the system.

Would it be possible to get -90C or so for 200W? With that compressor.

Yes, if you only use 2 cascade condensers (I'm using 3), increase the captube flows slightly, and charge with less R-14 and more R-170.