W116 300SD Air Conditioning Upgrade (Parallel Flow Condenser, Sanden, Larger Fan) - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 08-19-2015, 11:07 AM

Funola , I popped an aspirin as quickly as I could...

Tmadia · #17 08-19-2015, 04:50 PM

Quote:

Originally Posted by leathermang

That is a COMPLETELY MISLEADING STATEMENT.
Moving the danger involved FROM where it IS to the inside of the car.. that is not where the danger resides.

The danger is that you have propane at the VERY FRONT of the vehicle , in weak aluminum tubes under pressure AND ALREADY mixed with OIL..... it does not take much of an accident to cause that propane and oil to spray out into the air and be subject to any sparks caused by the collision. If you are inside the vehicle and slow or unable to exit ... you do not want a FIRE.... added to the situation... normal people realize this...

Everyone should watch ' The Great Waldo Pepper' with Robert Redford once early in their life. It will help you understand this concept.

The Risks of Hydrocarbon Refrigerant Blends - Article - TruckingInfo.com

"""""Hydrocarbon blends are highly flammable and in a confined space may burn or explode in the presence of an open flame, spark, or cigarette. No vehicle manufacturer has endorsed or authorized the use of hydrocarbon refrigerants in its current-production A/C systems, according to Red Dot. They can degrade gaskets and hoses designed for R-134a or R-12, making leaks more likely. Use them and you'll void the warranty.""""

Again, I don't want to start a refrigeration debate, but 90% of cars have high pressure gasoline running through thin wall tubes in a fuel injection system that can be broken in any collision. That same flammable oil is mixed with R134 which will cause it to ignite as well giving off phosgene gas, which is incredibly poisonous. To say that the small amount of propane in a condenser is more likely to ignite than gasoline is absurd, there is simply no evidence of that happening.

“I don’t know how much evidence it will take to convince some people that hydrocarbons are safe to use in car AC,” continues Clark, “It would be reasonable to expect that 20 years and millions of vehicles would be sufficient to sway even the toughest critics.”

hydrocarbons21.com Cold Hard Facts 2: 8% of Australian cars use HC refrigerants

Suffice it to say there is risk in driving an automobile. Whether that comes from the 20 gallons of fuel in your tank or the pound or so of propane in your AC it is all a potential bad day. Personally, I think the added risk of hydrocarbon refrigerant is minuscule enough to live with.

As an aircraft designer and mechanical engineer I understand that there are trade offs with every design choice. For me the horrible poisonous gas that R134 gives off when burned scares me MUCH more than the possibility of propane igniting.

By the way, the Great Waldo Pepper died burning in gasoline, which is much more dangerous due to it being a liquid and its tendency to stay localized to the accident location. So pop another aspirin and lets let the OP decide which way he wants go

Tmadia · #18 08-19-2015, 04:52 PM

Quote:

Originally Posted by funola

You are gonna give leathermang a heart attack.

I'm curious, is this what you'd use? Dust-Off Electronics Duster - Walmart.com

http://www.ebay.com/itm/3-Pack-Ultra-Duster-Canned-Air-10-oz-Pure-R152a-Eco-Friendly-w-Bitterant-/231162212354?hash=item35d2577002

Would the R12 can taps fit these cans? Would the spray nozzles leak air into the can during charge?

My 85 is currently running well with R134A, I have 6 cans of Envirosafe ES12A and a nearly full 30 lb R12 cylinder on the shelf. I really want to try the Envirosafe and then the R12 but the 134A is working well enough, I don't want to waste it.

Yup, that's the stuff. This guy shows you how to do it.

https://www.youtube.com/watch?v=dl4qOySVru0

leathermang · #19 08-19-2015, 06:28 PM

Quote:

Originally Posted by Tmadia

Again, I don't want to start a refrigeration debate, but 90% of cars have high pressure gasoline running through thin wall tubes in a fuel injection system that can be broken in any collision. That same flammable oil is mixed with R134 which will cause it to ignite as well giving off phosgene gas, which is incredibly poisonous. To say that the small amount of propane in a condenser is more likely to ignite than gasoline is absurd, there is simply no evidence of that happening.

“I don’t know how much evidence it will take to convince some people that hydrocarbons are safe to use in car AC,” continues Clark, “It would be reasonable to expect that 20 years and millions of vehicles would be sufficient to sway even the toughest critics.”

hydrocarbons21.com Cold Hard Facts 2: 8% of Australian cars use HC refrigerants

Suffice it to say there is risk in driving an automobile. Whether that comes from the 20 gallons of fuel in your tank or the pound or so of propane in your AC it is all a potential bad day. Personally, I think the added risk of hydrocarbon refrigerant is minuscule enough to live with.

As an aircraft designer and mechanical engineer I understand that there are trade offs with every design choice. For me the horrible poisonous gas that R134 gives off when burned scares me MUCH more than the possibility of propane igniting.

By the way, the Great Waldo Pepper died burning in gasoline, which is much more dangerous due to it being a liquid and its tendency to stay localized to the accident location. So pop another aspirin and lets let the OP decide which way he wants go

Anyone remember the Pinto ? Normal cars have the gasoline well protected in case of medium accidents.....many have fuel cells to restrict the rate the gasoline can exit the fuel tank.... They also have switches on the electric fuel pumps which turns off the pump when the engine stops.
Yes , r12 gives off phosgene gas when subject to direct flames..that is how leaks used to be detected.... a small flame turned colors when it burned that gas from a leak. BUT R12 is not in the same category for STARTING FIRES... when exposed to ignition sources as PROPANE....
So you are an aircraft engineer..... I flew a Huey in Vietnam ... and the difference between an accident with fire and without fire is significant and worth trying to avoid.

You totally missed the point on The Great Waldo Pepper...... his friend hit him in the head so he would not be conscious when he burned to death... he did not die in the crash... but the time the first to the accident had to pull him from the wreckage was cut short due to the aircraft catching on fire.... and that same condition can easily exist in a car accident.... where with enough time one might escape... if not cut short by fire....

vstech · #20 08-20-2015, 08:46 AM

Quote:

Originally Posted by Tmadia

Again, I don't want to start a refrigeration debate, but 90% of cars have high pressure gasoline running through thin wall tubes in a fuel injection system that can be broken in any collision. That same flammable oil is mixed with R134 which will cause it to ignite as well giving off phosgene gas, which is incredibly poisonous. To say that the small amount of propane in a condenser is more likely to ignite than gasoline is absurd, there is simply no evidence of that happening.

all I can say about the subject of propane in mobile systems is that it is ILLEGAL in the US...

so, unless you live in canada, you cannot recommend the stuff to anyone.

thanks.

and, last time I checked... zero cars have fuel lines running inside the cabin.

leathermang · #21 08-20-2015, 10:34 AM

Quote:

Originally Posted by vstech

all I can say about the subject of propane in mobile systems is that it is ILLEGAL in the US...

so, unless you live in canada, you cannot recommend the stuff to anyone.

thanks.

and, last time I checked... zero cars have fuel lines running inside the cabin.

OR in front of the radiator ......

Tmadia · #22 08-20-2015, 11:36 AM

Burning to death would definitely be one of the worst ways to go, next to being eaten by a bear, but maybe that's just me. If it is truly safety that has you worried you may consider comparing death rates by fire from fuel (gasoline/diesel) to hydrocarbon refrigerant.

I have a 1967 Chevy pickup and it has 19 gallons of gasoline right behind my seat, yes in the passenger compartment, for a total of 2,356,000 BTU. The propane in the AC has less than 60000 BTU. The gasoline does make me nervous sometimes listening to it sloshing around while driving.

I work with Hydrogen quite a bit at work and one thing I have learned about gaseous fuels is that they are inherently safer due to the fact that they tend to leave the area of the accident rather quickly. To me that is the point of poor Waldo. He was trapped at the accident site with gasoline pooled all around. Propane would have blown away rather quickly.

But hey, that's just my opinion. People are willing to live with all different types of risks, it's just important to understand the magnitude of those risks.

leathermang · #23 08-20-2015, 12:01 PM

Quote:

Originally Posted by Tmadia

Burning to death would definitely be one of the worst ways to go, next to being eaten by a bear, but maybe that's just me. If it is truly safety that has you worried you may consider comparing death rates by fire from fuel (gasoline/diesel) to hydrocarbon refrigerant.

I have a 1967 Chevy pickup and it has 19 gallons of gasoline right behind my seat, yes in the passenger compartment, for a total of 2,356,000 BTU. The propane in the AC has less than 60000 BTU. The gasoline does make me nervous sometimes listening to it sloshing around while driving.

I work with Hydrogen quite a bit at work and one thing I have learned about gaseous fuels is that they are inherently safer due to the fact that they tend to leave the area of the accident rather quickly. To me that is the point of poor Waldo. He was trapped at the accident site with gasoline pooled all around. Propane would have blown away rather quickly.

But hey, that's just my opinion. People are willing to live with all different types of risks, it's just important to understand the magnitude of those risks.

MORE MISDIRECTION...
We are talking about a gas which is highly flammable , PROPANE, put in front of the radiator under pressure and with which oil has been mixed.

I had a 64 Chevy pickup and understand about that gas tank... if you check on safety rules... you find that automobile manufacturers regularly apply for and get exceptions to the safety requirements for pickups compared to their automobile line. Side protection, rollover strength, all sorts of things.

funola · #24 08-20-2015, 12:11 PM

Quote:

Originally Posted by vstech

all I can say about the subject of propane in mobile systems is that it is ILLEGAL in the US...

so, unless you live in canada, you cannot recommend the stuff to anyone.

thanks.

and, last time I checked... zero cars have fuel lines running inside the cabin.

If you read the product description, it says: "Contains no CFCs, HCFCs, propane or butane"

The active ingredient of R152A is Difluoroethane

Here is the MSDS http://www.afrox-zambia.com/internet.global.corp.zmb/en/images/R152A379_73888.pdf

Here's wikipedia on it https://en.wikipedia.org/wiki/1,1-Difluoroethane says recently approved as a replacement for R134A

Anyone here actually tried it?

leathermang · #25 08-20-2015, 12:20 PM

Here is the MOST IMPORTANT question for anyone who has an R4 compressor...
and it never gets mentioned by these people suggesting these OTHER refrigerants...
the ability of that gas to mix with the OIL needed for lubricating your R4.. which has NO OIL SUMP .... called oil miscibility .....

http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1443&context=iracc

funola · #26 08-20-2015, 01:44 PM

https://www.youtube.com/watch?v=3wkBnhcyO3Y&feature=youtu.be

Tmadia · #27 08-20-2015, 04:46 PM

Quote:

Originally Posted by leathermang

Here is the MOST IMPORTANT question for anyone who has an R4 compressor...
and it never gets mentioned by these people suggesting these OTHER refrigerants...
the ability of that gas to mix with the OIL needed for lubricating your R4.. which has NO OIL SUMP .... called oil miscibility .....

http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1443&context=iracc

This document from the same Purdue publication says that hydrocarbon refrigerants work great with PAG and PAO oils.

http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1334&context=iracc

I'm going on 4 years with my 300CD and 6 years with the Chevy, both having hydrocarbon refrigerants and they still work great.

You bring up an interesting topic, which is oil and refrigerant, whichever type that may be. On high efficiency coolers, usually commercial equipment, they always have an oil separator between the discharge of the compressor and the condenser. Apparently having the oil in the condenser slows down heat transfer and degrades performance. There are oil separators for automotive applications so it may be worthwhile to look into it to see if it could increase the performance of our marginal systems.

leathermang · #28 08-20-2015, 05:19 PM

But you have to be able to get your system serviced... try finding AC people with the correct recovery equipment for any of the other refrigerants..
and note..... we are talking about MOBILE AC installations..... some of these things work just fine at industrial sites.... and are legal for them also....

vwnate1 · #29 08-20-2015, 11:21 PM

As I just replaced about 2/3 of the AC system in my '84 300CD and it still blow lukewarm dammit . (R134a now) .

I wish I'da known about the newfangled condenser as I paid through the nose for one and every little bit helps .

Back when I was a Junk Yard mechanic (in the good (?) old R12 dayze) we'd always scavenge Cadillac or whatever BIG GM car condensers as they were bigger and vastly more efficient .

Where does one get this improved condenser to suit a W-123 ? .

Also , I see you're still using the fan guard , I remove it first thing because it makes the fan noisier and less efficient ~ I'm old and have never yet put my finger in an AC fan .