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Comment by spqr0a1 | Hacker News Reader

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.

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>widely used in residential refrigerators and similar size systems.

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

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

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

Most of the world doesn't build their residential buildings out of light wood frame :/

A fuel-air explosion will not be contained by a reasonable amount of concrete or masonry. The real safety lesson is to control sources of ignition and prevent the buildup of released gases.

If your house is on fire, you best GTFO no matter what kind of refrigerator you have.

American homes have plenty of propane/natgas appliances anyway, so what difference does one more make?

People usually store their propane tanks outdoors.

And they have natural gas piped into the house.

the volume in a pipe is a lot less than what you'd find in a tank, especially considering the pressure in said pipes is usually one tenth of a psi (.6 kPa)

In the US it's typically more like 0.25psi, I don't know about elsewhere.

But it's connected to what you might consider a tank of nearly infinite volume. It's flow rate limited, but it's fast enough to get an entire house to explosion concentration in much less than a day. Perhaps only an hour.

Point is that we humans manage to figure out how to harness things that might be dangerous when they're useful. And hydrocarbon refrigerants can be very useful so we might figure out how to deal with the relatively small danger they pose.

I don't disagree to be clear, I'm just saying treating it differently than a gas pipe isn't totally crazy. A punctured refrigerant line will empty in a few minutes, and it's next to a compressor that'll likely generate a spark when it kicks on. Even if it just means we need to use thicker line, lets do it.

Notably, Propane has almost identical refrigeration characteristics to R-22, so it was an easy drop-in replacement for systems designed for R-22 when that was banned.

I don't see why, they're hardly less flammable

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.

> 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).

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.

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.

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

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