David, thanks for the additional information. That makes sense it would have been a display case. The refrigeration units you show look a lot like the one for the frozen food case at my dad's uncle's old store, which was installed sometime around 1936. It was a Frigidaire, and located remotely from the case, in the motor room. Other units for the refrigerated cases in there were Friedrich, and had been installed in 1955. The units put out so much heat that a heater wasn't necessary in that part of the building. The store closed in June of 1974, at the original cases and machinery were still in operation at that time.
I was in an old house (probably a museum, but maybe a house tour) several years ago. It was built sometime in the 1910's, and had an original built-in refrigerator in the kitchen. I remember it being constructed of beautiful oak with nickel hardware. The refrigeration unit was in the basement, and I'm thinking it was a Kelvinator, but it's been over 10 years since I was there.