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Post by turbokinetic on Aug 19, 2019 1:06:39 GMT
So; I have some of this gas ordered. It interests me because it's not a phase-out refrigerant; and can be purchased over-the-counter in small cans. I feel as if this experimentation will benefit hobbyists as well as professionals who choose to work on antiques but don't do so often. It should help those who do not have a license; or who are licensed but don't want to purchase a large container of something which may not get used often. Note that this is different from R1234YF, which is the current automotive refrigerant. Further note that absolutely no discussion about environmental politics is welcome in this thread.
We have determined that R152A works well in most old refrigerators. It increases the capacity when compared to SO2, which places more load on the compressor. If the system is operated within reasonable ambient temperatures and has an adequate design, this is not a problem. There are certain designs which seem to suffer more with this added capacity. For this reason I believe that investigation is wise, of new gases which become available.
The biggest problem facing use of R152A in place of SO2 has been, (in my experience and talking with others), improper operation of float valve metering systems. The density of R152A is far less that of SO2. This causes a change in float level, or a failure of the float to lift at all. Certain systems are relatively easy to modify to work perfectly with the lighter refrigerant, however others are not able to be modified within reason.
The HFO-1234ZE(E) falls between R152A and SO2; both in density and pressure - temperature curve.
Liquid Densities at 10F (kg/m3) Comparison to SO2
R124 1474.3 + 0.5%
SO2 1467.3
R134a 1334.1 - 9 % R1234ZE 1293 -13% (note - temperature not specified in chart)
R152A 986.1 - 33 %
Looking at this information above, I would expect that most high-side float systems designed for SO2 would still function with 13% less dense R1234ZE. We know that the 33% less dense R152A liquid will "usually" work in all but the most demanding systems.
The temperature - pressure characteristics are also closer to the original design SO2. I chose condenser temperatures to compare, because that is what seems to make the most difference to the stress on the machine.
At 40C (104F)
R152A - 129 PSIA R1234ZE - 111 PSIA SO2 -87 PSIA
So as you can see, there will be a capacity increase; but not as profound as the increase from SO2 to R152A. Since most of the SO2 antiques have plenty of excess power; this will be a side-benefit. It could be a real benefit for the low HP early Frigidaire Meter-Miser R114 systems.
Gas density is another interesting property. I'm not sure how much change in machine stress level it will provide. If I am not mistaken, it makes a real difference in sound waves traveling in the gas. We know that the very dense refrigerants change the sound of the machine. My hearing is poor but it seems that the heavier gases give a more "rich and smooth" sound whereas SO2 tends to be more tinny and crackly.
Gas densities at 10F:
Refrigerant Density (kg/m3) Comparison to SO2
R134a 9.23 + 332 %
R124 6.59 + 237 %
R1234ZE 5.71 + 205% (note - temperature not specified in chart) R152a 5.39 + 194 %
SO2 2.78
Of course all of this is just theorization and conjecture at this point. If anyone has more info, better math, easier tables to read - by all means please share!
Sometime next week I'll receive the R1234ZE and then will update more. Sincerely, David
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Post by Travis on Aug 19, 2019 1:44:17 GMT
David,
Excellent. What I’m curious to see is how it behaves in your D2 once you dump the original so2.
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Post by turbokinetic on Aug 19, 2019 1:56:12 GMT
David, Excellent. What I’m curious to see is how it behaves in your D2 once you dump the original so2. Thanks Travis!
I hope that my D2 lives forever and never needs to lose its original SO2 charge. I'll be on the lookout for a wounded but saveable DR of some model, to use for a test. At the moment I plan to test the R114 Meter-Miser and possibly a belt-drive Frigidaire with it.
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Post by birkie on Aug 19, 2019 3:36:56 GMT
This is great, it's the next closest match after R124 and will hopefully work well. A DR would be the ultimate test (as they're the largest challenge!). What's the status of Paul's DR3? Does that still need refrigerant?
Unfortunately, I'm on my phone and don't have good access to the spreadsheet I did a while back on modelling various refrigerants based on their equations of state, but as far as I remember about R1234ZE compared to SO2:
* Power draw would be about 15% higher
* Capacity increase is only 3% in an ideal compressor, but taking into account the lower compression ratio (leading to higher volumetric efficiency), it could be effectively 20%
* Discharge temperatures are minimal
I believe it is not miscible in mineral oil or alkylbenzene
As far as sound is concerned, it's complex and not well understood (particularly what makes a refrigerant quiet vs loud in a monitor top), so more data points on that would be nice. We never got to trying R227EA (which is also close) due to its relative unavailability. What makes it stand out is its extremely high density, higher than sulfur hexafluoride! It's the kind of gas you could fill a fish tank with and float an aluminum boat on top.
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Post by turbokinetic on Aug 19, 2019 14:18:21 GMT
This is great, it's the next closest match after R124 and will hopefully work well. A DR would be the ultimate test (as they're the largest challenge!). What's the status of Paul's DR3? Does that still need refrigerant? Unfortunately, I'm on my phone and don't have good access to the spreadsheet I did a while back on modelling various refrigerants based on their equations of state, but as far as I remember about R1234ZE compared to SO2: * Power draw would be about 15% higher * Capacity increase is only 3% in an ideal compressor, but taking into account the lower compression ratio (leading to higher volumetric efficiency), it could be effectively 20% * Discharge temperatures are minimal I believe it is not miscible in mineral oil or alkylbenzene As far as sound is concerned, it's complex and not well understood (particularly what makes a refrigerant quiet vs loud in a monitor top), so more data points on that would be nice. We never got to trying R227EA (which is also close) due to its relative unavailability. What makes it stand out is its extremely high density, higher than sulfur hexafluoride! It's the kind of gas you could fill a fish tank with and float an aluminum boat on top. Hi Aaron. I'm excited to try it, to say the least. Plan to exchange the R152A in my formerly R114 Frigidaire and compare power usage before and after; as well as the sound. Paul and I are still trying to work out logistics of getting his DR over here to fix it. Ironically, I have been around, and commissioned, HFC227EA-based fire suppression systems. They sell it as "FM200" or Sinorix agent. The problem is, the pressure is too low to spray out adequately. They charge a nitrogen propellant charge in on top of the agent; thereby contaminating it from a refrigerant standpoint. |
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Post by ckfan on Aug 19, 2019 22:50:13 GMT
This is great work David. Thank you for finding another refrigerant to compare. I’ll be excited to see how it behaves!
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Post by turbokinetic on Aug 20, 2019 1:59:43 GMT
This is great work David. Thank you for finding another refrigerant to compare. I’ll be excited to see how it behaves! Thanks. Hope to get it this week.
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Post by coldspaces on Aug 20, 2019 4:24:38 GMT
I looked at this refrigerant a few years back but it wasn't very readily available in the states. Sounds very promising, good luck, will be watching!
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Post by turbokinetic on Aug 20, 2019 12:43:30 GMT
I looked at this refrigerant a few years back but it wasn't very readily available in the states. Sounds very promising, good luck, will be watching! Thanks. I understand how things are sometimes hard to get and not always what they seem. I believe I have found a source of it in cans; but as you say I'll be very cautious about it until making some temperature / pressure checks to compare to the chart. |
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Post by CCL2F2 on Sept 2, 2019 1:52:45 GMT
You could try putting a tank of fm200 in the freezer and then pulling a vacuum on it to remove the dissolved nitrogen.
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Post by turbokinetic on Sept 2, 2019 2:31:47 GMT
You could try putting a tank of fm200 in the freezer and then pulling a vacuum on it to remove the dissolved nitrogen. That's a good idea, thanks! I'll have to see how readily available it is. When I work with the systems, they are on offshore facilities and are received pre-filled. I don't have access to obtain one from work in other words.
By the way; I did receive the R1234ZE however I haven't had an opportunity to do anything with it. Life got in the way, as they say.
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Post by turbokinetic on Sept 6, 2019 4:52:05 GMT
Finally got an update with this refrigerant! Life got in the way and I only just now got around to putting it in the Frigidaire.
As you may remember - this one had broken terminal seal and leaked out its oil and original R114 charge. I have been running it with R152A, which worked well. It did, however, put more load on the compressor. The rated running current is 1.9 - 2.1 amps; and the unit required 2.16 amps under stable running conditions with the R152A. I would expect it would have run for years like this, but none the less, it was a good candidate for this experiment.
Here is a video of the charging process: youtu.be/to99qC6pafU
Thoughts?
Thanks! David
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Post by ckfan on Sept 6, 2019 14:03:47 GMT
I’m going to enjoy watching this when I have a chance later. Very neat stuff!
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Post by turbokinetic on Sept 6, 2019 14:28:40 GMT
I’m going to enjoy watching this when I have a chance later. Very neat stuff! Thanks! It's very boring, and I yak incessantly about it during the video LOL!  The fridge is still operating this morning. It was cycled off when I checked. It's 70°F in the shop and the condenser is cool to the touch with the compressor cooler than body temperature by my estimate. |
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Post by ckfan on Sept 7, 2019 0:47:33 GMT
Excellent as usual. It sure looks like it is operating closer to what it should be with the low side in a vacuum like you saw. Current draw is lower too which is always good. Let’s hope it behaves! If it does I’d like to see a DR filled with it!
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