Morphing Air Conditioner into Autocascade System

[mytekcontrols]

Queue's Charge:

Ultralo: Found it. No percentages or wieghts were given, proprietary.
R600a (BP = -12C)
R134a (BP = -26C)
R508b (BP = -88C)
R14 (BP = -128C)
R740 (not condensed)

The R508B is simply an HFC replacement for the formally used CFC-13 in standard cascades. It is composed of 30-50% HFC-23 and 50-70% HFC-116. I would think in an autocascade that R23 (BP = -84C) could be directly substituted, since the presence of the R14 in the blend would give you the colder temperature.

Ultralo -- is this charge being used in the Cryostar freezers?

Interesting note; Polycold licensed their technology to Queue in the early 80's. I was directly involved with creating the first prototype chest freezer designed for -100C operation. I also remember that there was a heat up problem after extended operation, due to oil freeze up in the final captube feeding the evaporator. The charge used at the time consisted of CFC-114, CFC-13, HFC-14, and Argon (R740). Oil return was solely done via the phase separators. I would imagine that using a charge with R600a probably would have solved the oil migration/freeze up problems.

I remember we even talked about using 2 final captubes with shut-off solenoid valves. And then cycling back-and-forth, thereby allowing one captube to thaw out while using the other.

Utralo -- On the subject of using hydrocarbons as refrigerants. At an early point in time, you mentioned something about propane being used as...

We call it a "cold enema"

Are you ready to explain what and how this works?