Comment by samtho | Hacker News Reader

Comment by samtho | Hacker News Reader

For those not familiar, r744 is a type of refrigerant, similar to r134a and r404a. In any refrigeration system (A/C units, refrigerators, freezers, heat pumps), a type of refrigerant is required to move heat out of the target location (but heat pumps can reverse direction to move it into a living space to provide heating). Note that this is a closed system and had nothing to do with sequestering CO2 or anything, it just uses the specific properties of the gas to move heat. If I recall correctly, this refrigerant has been used in the industrial space for many years already for related cooling applications but is now being marketed as a something that EVs can utilize for cooling battery systems because it’s thermo profile allows it to be used very efficiently in this particular use-case.

The other thing I want to point out is that the linked article is coming from a website who’s domain is r744.com so they may have some vested interest in publishing this research. That is to say, I don’t believe this to be fluff or misleading specifically, just something to keep in mind.

R744 is just the refrigeration industry's name for CO2.

A wide range of substances can be used as refrigerants - basically anything that can be boiled and condensed. This includes the more commonly used ones such as r134a (tetrafluoroethane), r717 (ammonia). Even water can be used as a refrigerant (r718). It's just an industry naming convention for different chemicals.

>Note that this is a closed system and had nothing to do with sequestering CO2 or anything

Surely the fact it is a closed loop does mean it is sequestering co2.

In fact I'd go further and suggest that the best way of sequestering co2 is in ways where the sequestration is purely incidental, because then there's an economic imperative to do it.

Each CO2 heat pump has at most a few kg CO2 inside. US per capita annual CO2 emissions is ~14 metric tons.

That doesn't invalidate the principle.

A heat pump locks away a few kg of co2. While (more importantly) lowering the other side of the equation.

I'm not advocating it as a one stop solution to climate change, just that it does in fact sequester a few kg of co2.

It won't be permanent sequestration, though, or even necessarily long term. When these units are retired, their contained volume of CO2 will be reintroduced to the air, one way or another. In terms of scale, even several kgs of CO2 per person taken as a sum would still be a rounding error.

I suppose technically you are correct: a vanishingly small amount of CO2 is captured temporarily in units like these. It just doesn't matter for the issues where we need it to matter.

Well assuming we don't find anything better than heatpumps then homes will have a heatpump forever, so while your current heatpump might not sequester its co2 permanently, your heatpumps and your childrens heatpumps will effectively sequester co2 permanently.

An LED bulb saves ~5kg of CO2 a year v an incandescent. Is switching to that led bulb worth it? or is it too small to matter and not worth doing?

With current industrial processes, they usually will use some chemical reaction to create new CO2 because the can be certain of its purity. Most methods of capturing CO2 involve changing the chemical.

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