Here is a simple and detailed guide to building a dual evaporator phase-change cooler with one compressor.
Following onto the guide on building a single-stage
phase-change setup, here is the next step up, building a single stage dual
evaporator system . To get a better idea of the tools and skills needed, you
can refer to my previous guides here
For a dual evap system, I would personally go with at least a 3/4 HP Compressor.
For the 2 dual evap rigs I built, I used a 1HP Toshiba Rotary Compressor for
As seen in the picture, I bought a small condensor just perfect for the job
as well. Also in the picture, instead of the regular filter/drier, the one I
planned to used has 2 split outlets for the capillary tubes instead of one.
This is for refrigerant to be distributed to the 2 evaps.
I used a wooden plank cut to size to house my condensing unit, with nuts and
bolts and rubber pads to absorb the vibration so its silent.
As seen in the picture, I made a few coils at the discharge to minimize vibrations.
I put on shraeder valves for the high side (along disharge line just before
the condensor) and the low side (along suction line).
Next I put on a fan which I painted black.
For one of my dual evap setup, I wanted it to be placed behind a casing like
Therefore, I had to measure the length of suction hose I needed and the appropriate
layout. This is important as you should plan the layout before working on it.
It need not be from the back, and I made one that is designed to be housed below
the casing like a Prometia for my friend. It ended up looking like this:
I bought stainless steel hoses with stainless steel braids custom made to the
size I wanted and had them end with copper pipes:
I’ve also used corrugated stainless steel hoses without braid and had to braze
steel to copper. Brazing them on was more difficult and required a high silver
content brazing rod.