Morphing Air Conditioner into Autocascade System

[mytekcontrols]

If I get it right: You dont charge every refrigerant in a row but start with 2 mixtures (R123/22 and R170/14) and change the ratio of these two mixtures in the tuning process?

PhilippF look what time it is! Why am I still awake? I keep hearing a message in my head saying to complete unit... complete unit... I'm seeing spinning disks...

Seriously though, I talk about the ratio between the two mixtures, but I was just comparing what I call the liquids (R123/R22), and the gases (R170/14) as two separate groups, and applying a ratio of proportion. The liquids will be charged into the system by weight, and the gases by pressure. Each component is charged into the system (or transfer tank) one after the other, or in your words "in a row".

I wanted to charge the following way (please correct me if I tell nonsense):

Vacuuming and then breaking with R123 up to 1 barg (2 bara). Adding R22 up to 3 barg (4 bara) and then adding R23 up to 5 barg (6 bara). I imagine this will be a nice starting mix. Then turning the unit on and watching the first HX (where R22 mainly should evaporate) and perhaps add R22 until I have no significant temperature differential along the HX (I picture then being enough R22 to be there to cool the whole HX). Then repeating the same thing with the Evap (for R23). Do you think this will work?

As I said, the liquids are charged by weight. Then adding to the static pressure of the liquids in the system, you would add the R23 (in your case).

However if you do build a system with 3 cascades, you'll need something like R14 as well to get any appreciable cooling at the end (-110C to -120C system). If you don't want to use R14, then eliminate cascade#3 and phase separator#3. Of course this would be a -75C to 80C system.

Edit: Although having one less cascade wouldn't preclude the use of R14, it just wouldn't be quite as efficient.

When tuning the system by adding refrigerants the object is to minimize the temperature differential between the Suction-IN vs. the Discharge-OUT of each HXC, while still having a high differential from one end to the other. See example below: