Morphing Air Conditioner into Autocascade System

[mytekcontrols]

Thanks for the kudos

Now let me see if I can answer all the questions:

You mention a Suction Accumulator in your pdf file, but I don´t see it anywhere in your pictures?

N00b answered this one correctly. Yes it is an integral part of the LG rotary compressor, and is not something I needed to add.

What kind of phase seperator are you using? It looks like an ordinary accumulator?

The phase separator is simplicity in itself. Due to the small volume of the system, I was able to use the 1st bullet strainer as a phase separator (and it still serves the original purpose of straining any particulate matter before it feeds the cap tube). Take a look closely in both the piping diagram and the first photo in the PDF file and you'll see how it's setup.

How large of a load would you call the unit is taking in trapping alchohol

I have roughly calculated it as 50 watts based mostly on insulation losses. However I think it would be quite capable of handling 200 watts at pretty close to the same temperature (-30C). If optimized for -80C, I would think that 75-100 watts would be about it. Of course getting a little bit bigger air conditioning unit would improve this (I'm presently using the smallest LG unit for my application).

Ultimately though, would r22 help in the unit at all? Or just in the long run result in warmer evaporator temperatures

I have noticed R22 does help with autocascades having 2 or more cascade heat exchangers (my example only has one), and especially when trying to achieve -100 or better temperatures. A typical blend for a -100C 1 HP 3 cascade system would consist of: 10 oz R123, 6 oz R22, 60 psi R23, 40 psi R14 (gases are added to pressure of previous refrigerant). A system like this would require additional expansion volume because the compressor and stack volume alone would not be enough to maintain a reasonable balance pressure (total system volume should be at least 1/2 a cubic foot, with a charged pressure of 125 psi).

Is r11 a possible substitute for r123? Aside from environmental concerns

Yes R11 works just as good, and perhaps better for low temperature operation, since it is an excellent solvent for oil (insures that the oil is carried back to the compressor). I used R11 on an earlier system I built several years ago that was of similar size, and it worked great! Although I was also using R13 instead of R23, but these do have very similar characteristics.