Thursday, May 12, 2022

Problems With the Newer Refrigerants

This is one of the most important posts ever. Another problem i ran into, caused by yet another monumental technical and commercial blunder. Replacement of R11, R12 and R22 refrigerants which are chlorinated and are using mineral oil as lubricant with R134a, R410a, R404A which do not have chlorine in their chemical formula and use synthetic glycol or PAG (Poly Alkyl Glycol), POE or PVE as lubricant. The commonly used lubricant/refrigerant ratio is 1/4 (one ounce lubricant to 4 ounces liquid refrigerant).

First. They are saying that chlorinated refrigerants like older R11, R12 and R22 deplete the protective ozone layer of the Earth (ionosphere) hence they needed to be phased out and replaced with non chlorinated ones but to me this is highly controversial, because freon is 4 times heavier than air and chlorine 3 times. Ionosphere is the outermost area of the upper atmosphere where oxygen is converted into ozone by solar radiation and is as thick as the radiation penetrates. It's a self regulated process and ionosphere will be there in the same thickness as long as there is oxgyen.

Second. Chlorinated refrigerants may be anti-fungal (because they contain chlorine).

Third. Glycols though they outperform mineral oil in many applications including refrigeration, are highly hygroscopic. Which means they have an affinity for water and will attract water inside the pipes though the pressure is 2-3 times atmospheric pressure (on the lower pressure side of the system or before the compressor when in use).

Fourth. Unlike window ACs which are completely sealed, cars and homes ACs have 2 servicing valves or the so called core valves which are similar to core valves at the tires though they work at higher pressure (up to 200 psi or 13 atm on the high pressure side of the circuit or right after the compressor). Valves are sealed with tiny soft pieces of rubber.

Fifth. Lubricant in AC applications contribute to sealing the areas that have rubber seals. When not in use, the lubricant gathers at the bottom of the circuit and the valves "dry". Them they start leaking, but not only inside out, though the pressure in a fully charged system when not in use (on both low and high pressure areas) is about 50 psi at 50 degrees, 70 and 70 etc., they also leak, though much less, the other way due to partial pressure phenomena. Though there is pressure inside the circuit, that is caused by freon. Water vapor partial pressure is smaller inside then outside and water molecules that are also smaller get can also get inside in very small amounts, where they meet the lubricant, get dissolved in it until saturation and some end up in the silicon beads of the desiccant bag that is present in any AC circuit. And in there, if  there is no anti-fungal agents or additives in the circuits, water and oxygen contribute to developing mold and/or bacteria.

My car has been sitting in auction sites and shop for months and the valves have dried and leaked most of the freon, pressure was so low it was not triggering the switch that starts the compressor). After i first accidentally released some freon and PAG oil when i tried to refill the AC (and then i brought the hoses inside) i got very sick for about a month and a half after. Kinda realized what happened and bought a vacuum pump that is meant to remove all moisture from inside the circuit by applying vacuum. In vacuum, water evaporates faster or boils and vapors are eliminated by the pump. It is hard to obtain a very high vacuum due to continuous evaporation, at least until you eliminate most of it and it's a long process that might take up to an hour. But in the end it worked and the needle of that gauge was not moving down visibly when the pump was stopped, and the vacuum was achieved much faster after letting air in than the first time when moisture was present (actually should have used a digital gauge for deep vacuum, which measures in (mercury height) microns instead of psi, one psi is about 50k microns and for boiling water you will need some 1500 microns, and don't know if that is visible on a gauge marked in psi. 1/40 of one line on the scale). I also tried to replace the core valves, but did not realize i have bought two different sizes for each valves (4 valves in total) and i replaced only the low pressure one. My mistake.

Anyways, i've done it, added the right amount of freon, checked for the right amount of oil with some indicators i bought on Amazon.

As for newer than R134a. R410a and R404A which are newer than R134a are even worse. POE used in R410a saturate with water at 0.2 to 0.3 percent while PAG saturates at 0.7 which means there will be more free water in the circuit and desiccant bag.

But the next day. All my symptoms came back, though not as intense (it may be my immune system adapted to the strains that grow inside those circuits). Including belly pains which i had for a year before the accident. Which means the other car had it also. Which means they most do. Here in this image the pump is connected to the low pressure valve. The high pressure one which to me seems useless is in the bottom middle of the image next to the alternator. BTW i just remember, my low pressure valve tip was touching the cap when tightened which contributed to the leak.
This image shows the "zero" position of the gauge, which is a bit off to the right.And this the ultimate vacuum i have achieved in about an hour or soAnd yes i believe it's a good idea to start the AC in winter time at least once a week, to wet the valves with oil (glycol whatever).

An idea just came to me and went and looked for what kinda AC (heat pump whatever) a Tesla has. Since it should be obviously electric, like the window ones, of comparable capacity (around 10k btu), i was hoping it is as compact and does not have servicing valves. But no, it's got the same type of huge compressor and clumsy plumbing with long pipes that loose heat (cold) all cars have, is spread all over the what used to be engine compartment and has at least one servicing valve (yellow cap in the image). Why not make a compact AC (heat pump) of comparable size and price with the window ones, that last maybe 10 years, and could be cheap enough to be replaced all together or as cheap as the cost of servicing the existing?

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