Nov. 11, 1930: Einstein Gets Ice Cold

Love the sources listed for this article:

Source: Various

Missing from this is that the primary reason absorption refrigeration systems died in the marketplace was the fact that they required the use of highly toxic gases- like ammonia...

"Died in the marketplace"? Almost all RV refrigerators are ammonia-water-hydrogen absorption systems, which can be configured to get heat from propane, 12vdc, or 120vac--and possibly concentrated solar.

"...died in the marketplace..."

I was actually referring to the larger systems that were once popular for major installations, containing enough ammonia (or, I believe, sulfur dioxide was also used- I'm not too sure on that, though) to pose a serious risk to any living creature unfortunate enough to be on site when a leak occurred. I am not close enough to the industry to be really up to date on the newer applications of absorption systems, which seem to be the most promising approach for, say, solar-powered air conditioning. Most AC and refrigeration systems I have seen on small boats tend to be more conventional compressor-based systems, which never made much sense to me, other than the fact that freon and its newer replacements are generally less toxic. I think absorption systems have some potentially strong advantages over more conventional systems, if one can get around the toxicity issue...

My historical knowledge on this is limited, but I understand that sulfur dioxide systems were once used for multiple-apartment-type installations. I've even heard anecdote about dead canaries.

Ammonia is still the refrigerant of choice for many industrial-scale systems. Although it is a hazardous substance, small concentrations are not problematic. Moreover, leaks tend to be detectable by odor or instruments, mostly in time to be fixed before serious problems develop. Ammonia is also favorable on ozone depletion and global warming criteria.

There are a few large-scale ammonia-water absorption systems around, but most of the air-conditioning absorption systems use water as the refrigerant with lithium bromide as the absorbent.

Propane, isobutane, and other combustibles are also good refrigerants, but care must be taken about leaks, just as with other refrigerants. Sometimes toxicity governs, sometime flammability.

I worked in a blast freezer at a slaughter house the first summer out of high school. Ammonia based!! I know only because there was a leak. We all went outside for about 30 mins whilst repairs were made and the place aired out.

Granted that was 20 years ago, but it worked great (minus the one leak and 30 mins of lost production).