Continuing the discussion from Advice from the experts:
One of the replacements for 134a is 1234yf. Dodge is already using it, I personally don’t like it since it’s mildly flammable. If you look up YouTube videos you can see. The part that bothers me is if you are in a bad collision and it erupts into flames, it will spread quickly. There has been talks of CO2. All because the GWP of 134a is too high.
FYI, in case you are an ignoramus like me, I’ll save you some trouble looking stuff up.
GWP = Global Warming Potential
What 1234yf is.
Another source of information (not wikipedia)
I’m sure there are cheaper/better ways to price them, but for comparison, this is 10lbs of 1234yf vs. 30lbs of R134a.
Cost for 1234yf is SKY HIGH
vs R134a
PS: Dodge uses it because “Dodge” is really FIAT, which moved to it as required in 2011…
I have an HVAC buddy that jokes we should all just switch to propane. I just figured out why now, 1234yf is nearly propane already. 
Well propane is a refrigerant. But then again so is water & ammonia. I don’t want to deal with either of those.
But this one has been kicked around a lot, again, lately. Thing is, it’s not really very GOOD as a refrigerant, but it IS better than water, and more environmentally friendly than propane, R134a, etc. (we think, supposedly, right now)
And it’s a LOT cheaper.
And, yeah. propane [and propane accessories–giggle] actually works pretty well, but for the darned flammability thing…
Lol. It may be a good refrigerant but it’s toxic as hell. And you can use conventional heat exchangers/lines. It all has to be pretty much steel.
Interesting read.
Talks about the aftermarket sticking to R134a as the refrigerant of choice, even when servicing R1234yf systems, partly due to cost.
I think this may have been outlawed since this article was written, though…
6 years later, and still $99/lb.
Interesting read on R744 (CO2, the refrigerant of choice by Mercedes Benz, because the Germans think R1234yf has a silly name is too flammable).
EDIT: more stuff re: Mercedes/Germans/etc.
And another interesting article about why they WILL use R1234yf, and how.
and another
Similar from VW
Here is their video
I once worked in an OLD ice cream plant that used ammonia as a refrigerant. It always leaked a little and it always smelled. At least it’s biodegradable and renewable.
Kind of funny that 6 years ago, everyone was considering CO2 a dead end, now the EMEA mfgrs are all getting back on board.
Also funny to go from $99/lb to cheap at welding and paintball shops. But will be interesting to see what gets developed for gauge sets and hoses to deal with it.
So in talking with my supply house today, I found out that a couple Walmarts started using cascade CO2 refrigeration. He told me that the store ended up getting evacuated due to pressure reliefs popping off. This happened because they lost a couple fans. I looked for a news article on it, it was at the double decker Walmart/ Sams in East Dallas.
Sorry. Stupid question, I’m sure.
Even with this quicky download,
http://www.emersonclimate.com/en-us/Market_Solutions/By_Solutions/CO2_solutions/Pages/SubcriticalCO2Cascade.aspx
I’m unclear
Is cascade a brand, or a technology, or…?
Cascade is when you use a compound of two or more systems to reach really low temps.
For instance, you have a higher temp system take like your typical house unit. The evaporator is designed for about 40 degrees. That evaporator will feed a condenser of another unit. This will allow the overall cascade to run without ill effects. If you were to try to do this in a single stage, the compression ratio would be extremely high as well as potentially parts of the system go into a vacuum.
How much CO2 is in these systems? 20 lbs is less than 200 cubic feet (about 3 phone booths or so) if I remember my calculations correctly. Would seem like you would need a heck of a lot more in the volume of a store before you came close to an issue. Of course it would also make sense to design to vent the relief valves outside if there was perceived to be enough risk to evacuate the store.
Quite a bit more than 20lbs. I believe he was saying about 300 or so was lost. Believe it or not most reliefs I deal with are piped outside. But the equipment I work on holds normally anywhere between 800-5000 lbs of R-134a. In the past week I’ve bought 800 lbs.
Here is one of the CO2 tanks
Co2 is typically weighed due to it being a liquid at pressure and standard temps. So those sized bottles probably have ~50 lbs of co2 in them, of course it varies by bottle size.
50 lb of co2 (liquid) would take up 437.132 cubic feet if vented into the open air at 70° (21°C) and 1 atm, but if it was compressed at 300 psig it would only occupy 22 liters which is 0.776923 cubic feet
What is a good drop-in for R22 on a residential unit? MO99, R453a, …?
Or is this just a myth? “Drop-in” due to oil issues?
