Atmospheric techno-signatures

One of my morning podcasts this morning mentioned that one of the things they hope to do with the new James Webb Space Telescope is use it examine the atmospheres of exoplanets for chemicals likely to be present only if a technological civilization is present. Apparently among the chemicals that would be both easy to detect and a certain sign of artificial production are the fluorocarbons.

Yet another thing to worry about either the Gbaba or the rakurai detecting.

I think we can safely assume refrigeration on Safehold will be stuck with using ammonia (or similarly unsuitable for household use chemicals) for the foreseeable future.

Salisria wrote:One of my morning podcasts this morning mentioned that one of the things they hope to do with the new James Webb Space Telescope is use it examine the atmospheres of exoplanets for chemicals likely to be present only if a technological civilization is present. Apparently among the chemicals that would be both easy to detect and a certain sign of artificial production are the fluorocarbons.

Yet another thing to worry about either the Gbaba or the rakurai detecting.

I think we can safely assume refrigeration on Safehold will be stuck with using ammonia (or similarly unsuitable for household use chemicals) for the foreseeable future.

I think you can build a refrigerator on propane. Fire hazard but it's not going to be picked up by a telescope.

Loren Pechtel wrote:...

I think you can build a refrigerator on propane. Fire hazard but it's not going to be picked up by a telescope.

Yes. Google off-grid refrigerators.

Loren Pechtel wrote:

Salisria wrote:One of my morning podcasts this morning mentioned that one of the things they hope to do with the new James Webb Space Telescope is use it examine the atmospheres of exoplanets for chemicals likely to be present only if a technological civilization is present. Apparently among the chemicals that would be both easy to detect and a certain sign of artificial production are the fluorocarbons.

Yet another thing to worry about either the Gbaba or the rakurai detecting.

I think we can safely assume refrigeration on Safehold will be stuck with using ammonia (or similarly unsuitable for household use chemicals) for the foreseeable future.

I think you can build a refrigerator on propane. Fire hazard but it's not going to be picked up by a telescope.

not to mention that ammonia was used in household refrigeration for decades - apartment building i grew up in had an ammonia central refrigeration system. leaks are a bit unpleasant, but "unsuitable" is a matter of what you're used to.

Propane refrigerators typically use the propane as the power source, but some other substance as a more efficient refrigerant.

Given the tech aversion built into Safeholdian society, I don't think it a stretch to think there's going to be heavy resistance to home refrigerants that are not both odorless and non-flammable. Not when new-fangled ice boxes that can make use of industrially produced ice will become readily available without having to introduce potentially damnable or dangerous technology into the home. Between needing propane delivery and ice delivery, the convenience factor will be the same.

I grew up in the Australian outback, with no access to mains electricity. So we used kerosene firstly as a heat source then later propane. They worked on a principle of a small flame heating the refrigerant which then circulated and cooled the cabinet.
Very low powered and we switched as soon as power became available. Probably better than ice boxes though. Growing up we learnt to plan the door opening to minimise the time it was open.

Daryl wrote:I grew up in the Australian outback, with no access to mains electricity. So we used kerosene firstly as a heat source then later propane. They worked on a principle of a small flame heating the refrigerant which then circulated and cooled the cabinet.
Very low powered and we switched as soon as power became available. Probably better than ice boxes though. Growing up we learnt to plan the door opening to minimise the time it was open.

The heat-based refrigeration is inefficient. However, if you have propane but not electricity it's more efficient than making electricity and using that to run an ordinary refrigerator. IIRC it uses ammonia in the loop.

I'll admit that propane-powered refrigerators will be better suited for rural areas where ice deliveries would be problematic, but those same rural areas are typically conservative when it comes to change. I realize that the Safehold books have generally covered rural areas only when they are a theater of war and not dwelt upon potential urban/rural differences too much.