Here are some pictures of a project that I have been working on little by little over quite some time.
This is a Frigidaire AP-7 cabinet from approximately 1929 to 1930. I had the opportunity to buy this and almost passed it up because it was missing the entire condensing unit. The reason I went ahead and purchased it is because it had all of the interior components and was in decent shape.
I recently acquired several new-old-stock Whirlpool rotary replacement compressors (Thanks John L / Combo52!) These compressors were not equipped with mounting feet, and were supposed to be suspended from brackets. That is probably why they were not put to use before now. I fabricated some brackets to attach to the condenser frame so that this compressor could be mounted.
I wanted to keep the appearance of the original evaporator, which is (in its original form) not compatible with this type of compressor. The evaporator has had internal modifications, so that it functions more like a heat pipe CPU cooler versus a flooded evaporator.
There is an evaporator coil inside the header, Which is driven by the compressor system. The rest of the float style evaporator shell has a charge of working fluid in it, separate from the refrigeration circuit containing the compressor. There's just enough to fill up the header to the level of the original boiler tubes, and flow down into the tubes. As it boils in the tubes and vaporizes, the vapor rises and condenses on the surface of the coil inside the header. It then falls right back down into the pool of liquid. I was originally not sure how well this would work, because there's really no engineering information out there to size such a coil to work like this. I tried winding as many wraps of 1/4-inch tubing as possible and it seems to be adequate. I've got a good full frost on all the tubes of the evaporator indicating that the working fluid is boiling in the lower part of the evaporator.
It's not everyday you get to do the initial very first startup of a 1970s fridge compressor that has never run before. It is amazingly quiet.
Hope you enjoy the pictures of this beautiful old Frigidaire. As you may know, I have multiple belt drive Frigidaires which have original belt drive units. I'm not planning to start taking all of the belt drive units out and going with sealed systems, but I wanted to do this project to learn a relatively low-effort method to adapt the evaporator to work with modern compressors. There are people who do not want a belt drive due to the maintenance concerns. While I love the charm of the belt drives, I respect their viewpoint. There are plenty of cabinets which can be found that are missing the compressor, and this type of build will help keep those in service. In my humble opinion; the original evaporator is a very distinctive and prominent part of the cabinet. You see it every time you open the cabinet. Any substitution or additional evaporator added to the interior is visually unappealing.
Sincerely,
David
PS - please excuse the horribly messy workshop in the background!
(50 Year Repair Tech Beltsville,Md) 
Comes to the Rescue!
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