Using propane for your home A/C unit (was: home A/C and R-22 - cost perlb)


H

HVAC Guy

As of April 26, 2013, R22 has drastically increased in price for
the industry, if you you're lucky, you can work with your A/C tech
and he'll sell it to you wholesale if there's labor work involved
in the sale. It's still going to run you $80/lb and even a small
system is gonna set you back $500.
About the price increase, see here:

http://www.acbyj.com/r-22priceincrease/

===================
February 15th, 2013
R-22 refrigerant (freon) price Increases in 2013

The price of R-22 refrigerant has skyrocketed in the last 6 months. Due
to government regulations to “phase out” the production of “ozone
depleting” chemicals like Freon, production has continued to decrease
and has costs to skyrocket. R-22 refrigerant is 4 times more expensive
than it was just 6 months ago and is expected to continue to climb.

Due to this, contractors have bought it at an alarming rate and supplies
are greatly reduced. “Panic Buying” have forced some vendors across the
country to limit the amount of R-22 contractors can purchase in a month.

As the cost of R-22 rises, the cost of the new replacement Freon, R410a
continues to drop. It is a simple case of supply and demand.

Federal regulations call for a 90% reduction of production of R-22 by
2015 and to be completely obsolete by 2020. What this means to consumers
is outrages Freon related repair costs and eventually no choice but to
replace their HVAC equipment.

Most air conditioners manufactured before 2010 us the old R-22
refrigerant.

While a R-410a unit can just as easily develop a leak as an R-22 unit
can, from vibration, rust, stress cracks our sub-par welds etc., without
warning, the cost to replace R-410a is a fraction of R-22.
==================

Jon said:
Continuing to operate an old R-22 air conditioner is fiscally
foolish when you realize that the new 18 SEER units use half
the energy.
I thought that R-22 was more efficient than R134 or R410 (less of a load
on the compressor to achieve the same heat-transfer effect).

In any case, it's looking more and more that home owners are going the
DIY route by recharging their leaking home R22 units with propane (and I
know that you so-called pro's in alt.hvac will just love it when that
happens).

And I don't see why not, given that the auto-ignition temp. of these
refrigeration-grade propane mixes is higher than R134 and R410, and from
an electrical energy usage standpoint, using propane seems to cut that
down by 40%.

What I don't really understand is the safety hazzard issue of using
propane.

If you have a small leak (the sort of leak that is typical in an HVAC
system) it's going to take days or weeks for the system to de-pressurize
to ambient pressure, and the relatively small amount of propane in the
system is going to dissapate in the typical home during that time (if
the leak is inside the house).

If you have a furnace malfunction (blower-motor burn-out, fan-belt
breaks, over-heat cut-off malfunction) then again would you ever have a
condition where a run-away plenum temperature would bake the evap coil
to the point of combustion?

Could you get combustion happening *inside* the compressor due to some
sort of mechanical compressor malfunction?

Some sort of accidental dammage to AC lines (either inside or outside
the house) could release all of the propane within minutes or seconds -
is this the combustion hazzard that the HVAC industry / gov't is worried
about? Is this the only practical safety issue with using propane for
home A/C recharging?
 
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N

Nate Nagel

If propane and air are mixed in the system, the explosion can be
dangerous. AC systems are designed for totally non flammable
refrigerants. if there is some air in the system, and the happy home
owner adds propane, the resulting explosive mix can, well, explode.

Yes, you can get sparking inside the compressor.
I would think that it would be possible for a leak to not only let
propane out but let air in if it's on the low side, making that a not
unlikely scenario. It should be perfectly safe IF THERE ARE NO LEAKS
but do you want to bet that that is never going to happen on your system?

nate
 
C

clare

If propane and air are mixed in the system, the explosion can be dangerous. AC systems are designed for totally non flammable refrigerants. if there is some air in the system, and the happy home owner adds propane, the resulting explosive mix can, well, explode.

Yes, you can get sparking inside the compressor.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
But if there is air in the system the owner has other problems. That's
why a system is "evacuated" before recharging - with ANY refrigerant.
 
C

clare

I would think that it would be possible for a leak to not only let
propane out but let air in if it's on the low side, making that a not
unlikely scenario. It should be perfectly safe IF THERE ARE NO LEAKS
but do you want to bet that that is never going to happen on your system?

nate
How low does the low side of a refrigeration unit go???? Are they
not supposed to run somewhere between 40 and 85 PSI???
Not much change of getting ANY air into a system that has enough gas
in it to function at all. In fact virtually impossible to get air into
anything but an OPEN system (one with a severe leak or one with a slow
leak that has existed for a long time - system totally non-functional)
 
C

clare

I don't have any verifiable proof, or examples to point to. But, I'm not going to volunteer to have my AC system exploded for science.


Christopher A. Young
Learn more about Jesus
www.lds.org
.
.

I would think that it would be possible for a leak to not only let
propane out but let air in if it's on the low side, making that a not
unlikely scenario. It should be perfectly safe IF THERE ARE NO LEAKS
but do you want to bet that that is never going to happen on your system?

nate
LOTS of so-called "drop in replacement" refrigerants are mostly
propane. Not that I would recommend using ANY of them on a
refrigeration/ac system.

The big problem with propane, in my opinion, is it is a "heavier than
air" flammable gas - so if it leaks in your house, and the AC
coil/lines are in a asement, the gas may collect rather than disburse,
and you have a very real explosion/fire hazard.

Used in an automotive AC system, unless it leaks in your below-grade
or basement-connected garage, the hazards are significantly reduced.

If it leaks into the car when you are driving the mercapitan will get
you out of the car before it gets dangerous (before it reaches lean
explosive limit)
 
B

bob haller

 LOTS of so-called "drop in replacement" refrigerants are mostly
propane.  Not that I would recommend using ANY of them on a
refrigeration/ac system.

The big problem with propane, in my opinion, is it is a "heavier than
air" flammable gas - so if it leaks in your house, and the AC
coil/lines are in a asement, the gas may collect rather than disburse,
and you have a very real explosion/fire hazard.

Used in an automotive AC system, unless it leaks in your below-grade
or basement-connected garage, the hazards are significantly reduced.

If it leaks into the car when you are driving the mercapitan will get
you out of the car before it gets dangerous (before it reaches lean
explosive limit)
Imagine trying to explain a AC fire in your hme from a DIY propane gas
in AC. Your insurance company will be interested:(
 
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K

krw

Imagine trying to explain a AC fire in your hme from a DIY propane gas
in AC. Your insurance company will be interested:(
Here we go again, Haller's insurance insanity.
 
K

krw

How low does the low side of a refrigeration unit go???? Are they
not supposed to run somewhere between 40 and 85 PSI???
Not much change of getting ANY air into a system that has enough gas
in it to function at all. In fact virtually impossible to get air into
anything but an OPEN system (one with a severe leak or one with a slow
leak that has existed for a long time - system totally non-functional)
If air could get in, there wouldn't be enough propane to matter.
 
T

The Daring Dufas

If air could get in, there wouldn't be enough propane to matter.
I wonder if anyone has heard of a stoichiometric or near stoichiometric
mixture? It doesn't have to be that close but you do need enough O2 and
fuel to make a BOOM! The military and terrorists have used fuel/air
bombs with great effectiveness. If you pump O2 from your welding tank
into your AC filled with propane and overload the compressor until the
overload breaker in the compressor windings gets hot enough to trip, you
might be a Redneck. You should have two cameras setup, one close and one
far away. After it's all over have a surviving Redneck upload the video
to Y'all Tube. ^_^

TDD
 
T

trader4

  How low does the low side of a refrigeration unit go???? Are they
not supposed to run somewhere between 40 and 85 PSI???
That's right, it's the low side, but it's still way above atmospheric
pressure, so if there is a leak, it's going to leak out. When it gets
down to atmospheric pressure, then air could start to get inside.
But with a typical pinhole leak, I see refrigerant under pressure
getting out. Air getting in is going to be a lot more difficult.

A bigger worst case scenario would be that someone or something
slams into one of the lines inside near the furnace, severs it and a
pilot light
from the furnace, water heater, etc ignites the propane. But you kind
of have that potential with dryer gas lines, stove lines, etc too.

I wonder if any codes say anthing about it?
 
C

clare

I wonder if anyone has heard of a stoichiometric or near stoichiometric
mixture? It doesn't have to be that close but you do need enough O2 and
fuel to make a BOOM! The military and terrorists have used fuel/air
bombs with great effectiveness. If you pump O2 from your welding tank
into your AC filled with propane and overload the compressor until the
overload breaker in the compressor windings gets hot enough to trip, you
might be a Redneck. You should have two cameras setup, one close and one
far away. After it's all over have a surviving Redneck upload the video
to Y'all Tube. ^_^

TDD
The explosive range for propane is relatively narrow (and low) at 2.1
to 10.1% by volume at 20C and atmospheric pressure.

Gasoline is 1.4 to 7.6 BY VOLUME - Stoich is about 14:1 BY WEIGHT.
 
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C

clare

Can go as low as about 20 inches of mercury, maybe 25. And the situation you describe (for your opinion of the only possible way) does happen.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
Not on a functioning system - most will shut down before that happens
because that means a very low charge. Perhaps some home units may get
that low - I don't have much to do with them - but I've never seen an
automotive system get anywhere NEAR that low.
 
C

clare

What is "mercapitan" and is it used in propane
for heating and cooking and such? Never seen that
word, and online dictionary doesn't have it.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.
OK Smartass. Mercaptan. You've never mis-spelled a word?
Ethyl Mercaptan - the odorant in propane and natural gas
 
C

clare

At that moment, Billy Bob stops by with his propane cylinder, and adds seven pounds of propane.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.


If air could get in, there wouldn't be enough propane to matter.
Any idiot who will fill a leaky system without evacuating and
repairing it deserves to have his double-wide join the international
space station in orbit. Propane or not.

Good start for the Darwin awards.
 
C

clare

Please explain to me again, that the toothless home
owner with the ten big dogs tied out front, using
propane for his AC system. That sleeveless, truck
driving wonder who calls his wife by blowing the
horn on the truck "musical rendition of Dixie" will
evacuate to 400 microns, using two stage vacuum
pump, digital micron gage, and full flow ports with
valve core remover? Is that before he farts a few
bars of "anchors aweigh" or after?
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.

But if there is air in the system the owner has other
problems. That's why a system is "evacuated"
before recharging - with ANY refrigerant.
Which is why in Canada it is technically illegal to open a
refrigeration system without a licence - which requires training.

Used to have mine for automotive AC but let it lapse many tears ago.
 
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T

The Daring Dufas

The explosive range for propane is relatively narrow (and low) at 2.1
to 10.1% by volume at 20C and atmospheric pressure.

Gasoline is 1.4 to 7.6 BY VOLUME - Stoich is about 14:1 BY WEIGHT.
That's what the fuel/air delivery systems in gasoline engines strive
for. ^_^

TDD
 
H

Home Guy

Stormin said:
What is "mercapitan" and is it used in propane for heating and
cooking and such?
Are you just clowning around, or have you really never heard of
mercaptan?

It's what they add to natural gas to make it smell like rotten cabbage
so you can smell gas-line leaks.

They apparently also add it to refrigerant-grade propane.

And by the way, propane is apparently approved for use in commercial
refrigeration plants.

The way things are going with the drive to increase energy efficency in
consumer devices and appliances, it's really only a matter of time when
residential AC units are going to start using propane. I mean jesus
christ - natural gas is already being pumped into and combusted in
millions of homes, in furnaces, water heaters, stoves, dryers. It's not
like we don't know how to handle flamable gases in residential
appliances.

The amount of gas circulating in a residential AC system is a pittance
anyways, and anything short of a burst pipe is not going to be a
hazzard.
 
C

clare

That says it all.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.

Perhaps some home units may get
that low - I don't have much to do with them -
I do know MINE won't - it shuts off to protect itself if pressure is
either too high or too low.
 
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G

grumpy

G, doan no.
..
Christopher A. Young
Learn more about Jesus
www.lds.org
..
..
Ever try typing a word you don't know into geegle?


Stormin said:
What is "mercapitan" and is it used in propane
Comon Chris the word is few other it's cool man, do you digit man
you need to to NYC bronx section.
 

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