R22 vs R410a and R12 vs 134a

June 29, 2011, 08:38:08 pm

With more than one thread going about air conditioning and refrigeration problems, I might as well start another. R12 and R22 were the most common refrigerants used in cars, refrigerators and home air conditioners until they were banned as depleting the ozone layer.

Quote from Modern Refrigeration and Air Conditioning copyright 1968 (maybe not that modern). Desirable characteristics of a fluid used as a refrigerant: It should be nonpoisonous, nonexplosive, noncorrosive, nonflammable and nontoxic. Leaks should be easy to detect and locate. It should operate under low pressure (low boiling point). It should be a stable gas. Parts moving in the fluid should be easy to lubricate. It should have a well balanced latent heat of evaporation value per unit of weight. A minimum difference between the vaporizing pressure and the condensing pressure is desirable.

My parents had a refrigerator that used sulfur dioxide as the refrigerant. Fortunately it never developed a leak, the house wasn't that tight anyway, and none of us died. Propane is a good refrigerant except that it is flammable and explosive.

Several members have correctly stated that the newer refrigerants do not work as well as the old. Here are some links to articles that may explain why.

http://fire.nist.gov/bfrlpubs/build02/PDF/b02186.pdf
Just read the abstract unless you really like the details. The essence is that both types can be engineered to operate equally at a specific temperature or test value. Once the temperature changes performance can be different with the new usually not as good as the old stuff.

Automotive air conditioning and R12 updates (R134a and more)
Probably geared more toward people like you and I.

RV Refrigerator Efficiency 101 - RV UNIVERSITY
Something about the efficiency of the propane or absorption refrigerator.

Last December to take advantage of a federal income tax credit, manufacturers rebate, a city rebate, and a gas company rebate, I replaced my 14 yr old 4 ton home air conditioner with a new 3 ton unit, along with the gas furnace. The dealer thought 3 ton was all I needed. So far it has kept the house cool with temperatures in the low hundreds. Part of the deal was to check the house for air leaks, weather stripping around doors and windows, amount of insulation, etc. It does run almost constantly during the day, but on a low speed until it gets really hot. We catch the condensate in a barrel and use it to water plants. The old unit seemed to produce more water, but it does not seem to be more humid in the house. The 3 ton condensing unit is larger than the old 4 ton unit. The fins on the coil are closer together as a means to increase the efficiency. This comes at a price though as it traps more dust, lint, spider webs, pollen, fuzz, or whatever happens to be in the outside air. Increased run time helps with the collection. After 3 months of operation I had to remove the grill and carefully vacuum off all the fins. I used to do that once a year or less. The new AC is much quieter than the old one. I think it will take a couple of years to determine if the new unit is using less energy. So far it's been really hot this year.

Anyone with a new roof air should check the condenser fins for an accumulation of dirt. Said dirt will convert your 15k BTU to a smaller value.

Re: R22 vs R410a and R12 vs 134a

Reply #1 – June 30, 2011, 05:52:50 am

We in the transportation industry went through this deal several years ago with R12-134a, now 134a the "new freon" is on it's way out. The new refridgerants are not as efficient, they operate at a higher pressure, and use diffrent oils. Because they are not as efficient they require larger condensers and bigger fans to allow for more heat transfer. With that said converting an old system to a new "freon" usually does not work very well and is very costly. It's going to be a real problem with us that own older RV's where it is not like your house you can't just remove the old dash air and replace the entire system, roof airs will just evolve like other appliances.

Re: R22 vs R410a and R12 vs 134a

Reply #2 – June 30, 2011, 09:12:00 am

Someone long ago replaced the dash air with the new stuff (only cools moderately after a charge which is good for a few days). Replaced my two roof air units last year prior to my trip out west because Onan service assured me that my old units that would turn the coach into a meat locker were drawing too much juice and causing the ATS to open while on generator (turned out to be a failing ingition coil on the generator). New Coleman mach power saver units don't hold a candle to the old ones IMO.

Re: R22 vs R410a and R12 vs 134a

Reply #3 – June 30, 2011, 09:38:52 am

I guess I will find out tomorrow. I am having a Penguin 13,500 installed in the bedroom. I would have gone for a 15,000 but I would have had to change the thermostat and plenum. Let's hope Dometic altered the mechanical part to offset the less efficient coolant. The quoted cost will be $800 assuming the new unit really is a plug and play replacement.

Re: R22 vs R410a and R12 vs 134a

Reply #4 – June 30, 2011, 10:20:51 am

I love the Penguin name! We were well in the 90's last week at a campsite and our 13.5 was meat locker perfect in the bedroom. Forward, the 13.5 just dropped the temp down to 86 from 96. We were in direct sun until late in the day.

While I was never really happy with the R12 to R134 conversions, the two later cars we have now really work well with the 134 so you have two reviews to make. The GPS and the Pengie. Did read about the Emperor Penguin going off course last week and ending up in the tropics with a stomach full of sand.

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