5 ms·
HFOs are third generation refrigerants, replacing HFCs, which in turn replaced CFCs. In 1985, CFCs were recognized as destroying the ozone layer, so they were
by brilee 4y ago
HFOs are third generation refrigerants, replacing HFCs, which in turn replaced CFCs.
In 1985, CFCs were recognized as destroying the ozone layer, so they were banned in 1989 and replaced them with HFCs that didn't do that.
The problem with HFCs was that they have 5,000-10,000x greenhouse warming potential relative to CO2. So in 2006 the EU mandated that cars replace HFCs with less potent substances. After 10 years of development and testing, HFOs were finally phased into usage, with most cars using HFOs in their air conditioning.
Heat pumps and HVAC units seem like they're a decade behind autos, but their HFCs should likely be replaced with HFOs, too.
The TFA comes from atmospheric degradation of these HFOs. Scaremongering about TFA without the counterbalancing story of why TFA is showing up and the decades of social, political, and technical work behind HFOs, pisses me off to no end.
- coryrc 4y agoJust use propane. This bullshit with inventing ever more elaborate synthetic compounds which turn out to be toxic has got to stop. We should be denigrating "the decades of social, political, and technical work behind HFOs".
- usrn 4y agoI'm still not convinced propane/butane makes sense in automotive ACs. EDIT: because it ignites during accidents.
- skocznymroczny 4y agoLPG propelled cars exist and are popular in some parts of the world, and it doesn't seem like they're more unsafe than diesel or gasoline equivalents.
- toomuchtodo 4y agoNeed to get the operating pressure of CO2 down.
- coryrc 4y agoThe pressure is intrinsic to the compound. It cannot be lowered.
- toomuchtodo 4y agoTIL, thank you!
- SoftTalker 4y agoMany things can ignite during accidents, such as the 10-20 gallons of gasoline in an average automobile tank. The tanks tend to be pretty well protected, and an air-conditioner condensor is normally at the very front end of the car, but that design could be changed.
- ars 4y agoThere's around 3lb of it, around half a gallon equivalent of gasoline. That's not nothing, but it's not that much that we should be extremely worried - there's around the same amount of fuel in the various lines running from the gas pump to the engine. It also helps that as a vapor it will dissipate very quickly.
- dashundchen 4y agoI think the future refrigerant for many applications is CO2, with a global warming potential of 1. Volkswagen put heat pumps with CO2 based refrigerant in their latest cars. Japanese company Sanden makes components for CO2 based heat pumps and compressors. https://www.sanden.co.jp/english/products/car/lineup/CO2-Compressors.html https://www.sanden.co.jp/english/products/car/lineup/CO2-Com... Project Drawdown estimates addressing the emissions of refrigerants to have one of the biggest impacts on climate change. https://www.drawdown.org/solutions/table-of-solutions https://www.drawdown.org/solutions/table-of-solutions
- marcosdumay 4y agoI wonder what is the advantage of those complex compounds (CFCs, HFCs, HFOs) when compared to CO2. EDIT: Well, duh, answering my questions after a quick search, CO2 liquefies in a much lower pressure than most gases.
- colechristensen 4y agoIn short, the energy efficiency of moving heat depends on the working fluid.
- semi-extrinsic 4y agoActually CO2 works very well, but you typically run it in a transcritical cycle where there is a gas cooler instead of a classical condenser unit.
- marcosdumay 4y agoOr, in other words, for using CO2 efficiently on an environment-temperature heat pump, you need it to sustain higher pressures at both the hot and cool sides, and both the pump and nozzle to survive dealing with a higher density fluid that acts in many ways like a liquid. That explains why people keep searching for a different gas. What is interesting is that it's probably the best gas for that kind of cycle on environment-temperature, as it's too cold for water and amonia, but a low condensing pressure is a benefit here.
- hotpotamus 4y agoYeah, I don't really know that much about refrigeration, but that's my take as well. If I had a choice, I'd just run all my stuff with propane, but I don't really know how feasible that is - could I just jury-rig up some hoses and go around charging things? Or are there parts of the system that won't abide by that? I believe the stated rationale against propane is flammability, but is that really that much of a concern? Presumably you aren't mixing oxygen and propane in the system, so basically you've just got propane lines circulating in your house/car. Big whoop, I've got methane lines in my house already, and the car has plenty of other flammable things too.
- coryrc 4y ago> but I don't really know how feasible that is Only if they run similar pressures. R-22 is basically the same pressure as R-290 (propane) but all the newer stuff is much higher. I think that means it ends up icing over really quick.
- SoftTalker 4y agoA propane/isobutane blend is a good replacement for R-12 which was the refrigerant used for air-conditioning before CFCs were banned. Straight propane as you note is better for freezers than air conditioners. A problem with blended refrigerants is that if there is a slow leak the blend will change as the refrigerant leaks out, due to the different partial pressures. That makes recharging more difficult, you basically have to vacuum out the system and recharge with the correct mixture. Also, propane and isobutane are both flammable, but other than CO2, most refrigerants are to some degree.
- Aloha 4y agoSome of them produce quite nasty byproducts when they burn too.
- coryrc 4y agoErr, my last statement refers to what I think happens if you replaced R410a with R290 without further changes.
- gennarro 4y agoYes, most hvac and refrigeration units are a generation behind, so perhaps the issue will only grow with time. More info: https://appliance.report/gwp/ https://appliance.report/gwp/
- kurupt213 4y agoThese are precursors or degradation products for a lot more than refrigerants and propellants. - Any nonstick or stain resistant coating (scotch guard /Teflon) - Chemically inert Polymers for fixtures in chemical reactors (more PTFE variations)