Hi,
I need some advice on how to proceed if I知 looking to improve my cooling.

keep in mind I知 not in the hvac field, and don't do this for a living, but have some basic knowledge on the subject.
But mainly I just happen to have some old soda machine parts and enjoy tinkering and learning.

Here's my current situation;
My system is setup to chill a container of moving water/salt solution, about 3gal.
Which is used to fast chill beverages

The system consists of an insulated container, such as a large stew pot, that is wrapped with copper tubing that acts as my evaporator, the compressor is a 1/3 hp, 4500 btu, its running with r134a. Not sure about the condenser it came from a soda machine using the same type compressor. I知 using suction accumulator, not sure if its needed or not, but I had it and wanted to be safe.

The system works and chills well down to 27deg F.
I was shooting for around 10deg. F.

I thought the evaporator coil wasn't big enough to cool adequately. So I tried different evaporator configurations, such as more wraps around container, larger tubing, smaller tubing, different length cap tubes, etc.
after everything is reconfigured, adjusted, and recharged, it still only gets it down to about 27deg.


Now I知 thinking R134a isn't going to get it cold enough with my setup. So I知 leaning towards swapping out the compressor for one that can run r507a/r404a in order to get colder.
I would like to get colder than needed and then tune it back a bit to the temp I知 looking for.

So, I need some advice from the folks that do this daily.

thanks mvtop