[spqr0a1]

Ethane (R-170) is a fine low-temperature refrigerant for lab equipment. The performance characteristics are at least as good as halocarbon refrigerants. The main drawback is flammability but propane has a similar concern and is already widely used in residential refrigerators and similar size systems.

[xxpor]

>widely used in residential refrigerators and similar size systems.

Not in the US (because of the flammability), unless something's changed very recently.

[xenadu02]

> Not in the US (because of the flammability), unless something's changed very recently.

I don't know when it changed but R-290 (propane) is allowed up to 13oz. My ice maker uses it. I believe it must also be sealed without service ports both to prevent leaks and prevent anyone from connecting normal A/C service equipment to the system. Service requires emptying the system then brazing service ports onto the fill pipes (which are left much longer than normal for this purpose).

[akira2501]

In commercial applications you'll see R-290. It's often used in low temperature applications, like ice cream display freezers. I've seen them in gas stations and pizza shops quite a bit.

[thaeli]

In the last few years, the US has finally started allowing small appliances containing limited quantities of flammable refrigerants.

[jabl]

USA is kind of the exception. In much of the rest of the world, propane or butane are the norm in domestic refrigerators.

[RobotToaster]

From personal experience things using propane refrigerant seem to make a high pitched noise, I'm not sure if that's a property of the refrigerant or how devices using it are built.

[dsfyu404ed]

There's no "reason" propane has to be louder but most propane refrigeration systems are used in industrial or cost-conscious applications where making the equipment quiet is less of a priority. When designing pumps it takes a non-trivial amount of engineering effort to ensure that the bulk of the noises emitted are above/below human hearing range.

[vondur]

I've seen pentane used in small refrigerators in the US.