Morphing Air Conditioner into Autocascade System

[jinu117]

Been pondering over this... what kind of impact would suction accumulator will have in autocascading system when load condition is not optimal per say. Would it start trapping r-123? Would R-123 be carried along with other gas state refrigerant? Would artificial boiling point of r-123 get much lower due to the pseudo refrigerant condtion? There is only so much volume of liquid r-123 we will have to begin with and I am starting to wonder if R-123 can pool itself in suction accumulator as liquid by itself effectively reducing amount of it flowing through rest of loop
Comments Michael?

[mytekcontrols]

There is only so much volume of liquid r-123 we will have to begin with and I am starting to wonder if R-123 can pool itself in suction accumulator as liquid by itself effectively reducing amount of it flowing through rest of loop

It shouldn't "pool" in the accumulator because a properly implemented suction accumulator shouldn't hold up much, if any liquid. Some accumulators (like the ones on small rotary compressors) are nothing more than a small receiver which adds additional volume to the returning suction line, and larger ones normally have a dip tube positioned slightly above the bottom. In either case the object is not to hold up liquid, but to allow it to flash off (expand) before entering the compressor. On a small rotary compressor (see image below) the accumulator is of the non-dip tube variety, and is normally plumbed with the inlet coming into the top, and the outlet going into the compressor. This type will not trap any liquid.

Edit: Yes Nol is also right, some of the dip tube style suction accumulators have what I would call metering holes drilled in the side of a dip tube riser which is open on the top. Any gas present would easily make its way out of the accumulator through the dip tube's top opening, and any accumulated liquid would be restricted by the metering holes along the side, thereby returning at a controlled rate.

Would artificial boiling point of r-123 get much lower due to the pseudo refrigerant condtion?

Yes it will. In the CFC days, R-114 would have been the refrigerant of choice for the first component in an autocascade. When the non-CFC era first hit (and HCFC's were still considered to be ok) a combination of R-123 and R-22 (when in proper proportions) exhibited a similar boiling point as the formerly used R-114.