Here's one of my favorite pieces of my collection! It's a 1930's Grunow "Carrene" fridge. I made a video about it recently and want to share it so that you can see and hear about some interesting early technology.  I have done captions on this video, per request of some viewers who speak English as a second language and find my speech too fast. I hope all benefit from this. Please let me know how helpful it is. It's time consuming to review and edit the captions.

Thanks!

Sincerely,

David

... that the video link was not working in the original post. That was a mistake on my part and it has been fixed.

Thanks Ralph - it's definitely an interesting design. Mine came from a retired engineer from Rolls-Royce aircraft engine division. He had taken care of it even in his old age. After his passing, his family found the Grunow out in a barn, still running. He had been oiling the condenser fan motor for years and keeping it going. 

Hi John.  Yep, I really do admire the out of box thinking and unique designs of the era.  Seems that all the other companies were playing for third place, following "The Two Generals" in first and second, far ahead.  General Electric with the Monitor Top, and General Motors with their Frigidaire were a distant first and second, due to the amount of money they had to spend on R&D.  

Grunow produced a good unit, but in the end the cost of the amount of materials necessary to make it with the size of compressor needed to get the cooling power at low pressure probably made selling them unprofitable. As you said R114 and ultimately R12 were very safe, and it turns out that explosions due to the low 100's PSI they run it wasn't really a concern after all. With the smaller, low-cost compressors they work with, it was just not possible for Grunow to compete it seems.

Hi Dan; thanks for the link to the article! That was an interesting read. I had seen it before but it had been a long time. I'm not entirely sure why he states that the Grunow would be hard to service, because it is serviced in s similar manner to other sealed units (using a hermetic service kit on the receiver.) The only thing it has which was unconventional for the time, is the activated alumina drier, located inside the receiver. That would need regeneration or replacement which is never an issue on SO2 machines.   It may also be because, back in the day, some people didn't consider it necessary to use a vacuum pump with SO2 units, because they could purge and sweep the system of air, by repeatedly vapor charging and venting the system until the residual air was diluted enough to be a non-issue. This would never work with a vacuum system such as the Grunow, however.  (Note: it has been found that sweep-charging is ineffective because it does not remove moisture... but back in the day it was an accepted practice.

John; yep I tend to agree that the General Electric CK Monitor Top; and others with the GE Scotch Yoke mechanisms are about the pinnacle of refrigeration engineering. Those are typically going to stand the test of time.  The CA machines with the methyl formate vacuum systems also are pretty good, except for the breakdown of the MF and noncondensable gases. They tend to get stuck / locked up if run for a long time with an excess of NCG and a bad crankcase heater. However they can often be reactivated with "special equipment" and then continue to work for years as long as the NCG bleed procedure is done.