How to make R-290 from barbecue gas (propane)
Over the last couple of years, there has been a lot of interest and change towards basic hydrocarbon refrigerants that are easy to get/make, and cheap, and have virtually no abillity to damage the environment!
I think, finally, that people are starting to wake up to the cartels of Dupant and others who have foisted cfcs and hfcs, etc. on the planet and that people are realising that the scare mungerring about houses exploding because of a hydrocarbon filled fridge are not the problem people thought they were!
Now we see fridges starting to adopt r600a, isobutane, basicly a high pressure isoner of butane instead of R-134a and it is working way better!
You get more cold for your buck, and the same go's for other systems, CO2, carbon di-oxide is also starting to get used and is turning out to be very effective non flamable, and totally cheap, and has a global warming potential of 1, not about 3000 like 134a!
It's downfall is that you need really thick compresser housing and pipes, but it is getting developed and I think we'll be seeing more of it in the future!
The other one that is an almost direct replacement for the old r-22 is good old propane, barbecue gas!
The differences are that it appears from the tests I've read about to be somewhere from 30 to 60% more efficient than R-22, and of course here in Australia with our brilliently conceived carbon tax (Thankfully Now abolished), R-22s price has gone mad, and add to that, it is technically phased out, so will become hard to get anyway.
R-22 is still a CFC after all!
So, why cant' we just run bbq gas directly into an air con?
Well, you can, and it will work, but it has the odorant, the deliberately added sulpher containing smell which some claim may effect motor windings and compresser parts over time, and it also may contain moisture which you really don't want in there eather!
So, when you buy proper r-290 which you certainly can, you are basicly getting a more pure gas with very little moisture and no smell.
There are many companies already selling such.
I wanted to try making some myself from a standard bottle of bunnings gas which is a damm side cheaper than all these, and definitely way cheaper than all the cfcs and hfcs!
I made, and am now re making more propperly, a filter/distilation system to do this, and it was simple as it turned out, and I hadn't even expected it to work as well as it actually did!
My original intent was to dry the gas, but to my amazement, silica jel takes up the odor incredibly well also!
By this stage I have bought some proper fridgy tools, hoses, gages, adapters etc, and a large bag of 1/4 inch shrader valves with pipe tails.
The silica jel filter I mentioned in the last article made of a hose waterring system filter cartridge was the first attempt, and it was a bit leaky, not really designed for propane bottle pressures, but it held, and it proved a point!
I now also have a couple of old compressers off old fridges with the 1/4 valves brased onto the in and out lines.
The other thing I bought amazingly cheap was a vaccuum pump, oil filled, 2 stage, for refrigeration work, and it's small, but it pumps down, it claims, to 25 microns if left long enough, and that is definitely more than good enough for our purposes here!
All this can be easily got on Ebay!
My second generation silica jel cartridge is much better, and it's made from 2 x 3/4" water hose tap adapters, the standard nylexO-ring type, They try to sell you the big ones now, with an 1" to 3/4 adapter.
I found some small brass ones with no adapter that came with a garden hose metal Y splitter at Bunnings!
I could not get hold of 1" threaded pipe or I would have used the larger ones.
Note gal pipe is not well machined on the ends, so avoid it for this project unless you have a leythe and can machine nice ends on it that will seal with the rubber washers.
I then got 2 hose filters, Bunnings call them Mexican hats, and a bit of brass 3/4 threaded rod.
Actually, you can use 2 bits of the threaded rod and a threaded joiner, Just use some good grade teflon tape to seal the join well if you want to do that!
The bigger you can make the cartridge, the better, the more silica jel you have there, the better and longer it runs before you have to change it over.
We then silver soldered a refrigeration schrader service valve with it's copper pipe removed directly onto where the hose would have connected to each of the tap adapters.
and replaced the standard rubber washers with the mexican hat versions.
So, I now had a good quallity serviceable cartridge that easily takes full gas bottle pressure with no leaks!
Next you make 2 plugs, each from about 5 squares of toilet paper and fold that length wise into about 8 so you have a long strip about 1 and a bit CM wide.
Tightly roll this up and you can roll it along a flat surface to pack it as hard as you can get it.
You should end up with a Puck-like plug that will force hard into the end of the threaded pipe.
Push the plug in so it is just inside the end of the pipe, and then fill the pipe up from the other end with silica jel until it's almost full.
Tap the pipe and the jel should pack down so you can push in the other plug on top of it.
keep Tapping the pipe and pushing the plug in until it's all tightly packed in and this plug is also just below the edge of the pipe.
You want to avoid any toilet paper getting between the pipe end and the rubber washer.
Now screw the end caps you've made on nice and tight, and you have a damn good silica jel gas drier-filter!
The toilet paper is an excellent filter and containes the silica jel and its dust, and the mexican hat strainer washers will catch any bits of toilet paper lint that might get loose.
You can re use the toilet paper plugs many times, just be careful to always put them back in the same way around. You do not want the dusty side facing the wrong way, or your compresser might end up with silica jel dust in it, Not a good thing!
Silica jel can be got very cheaply in the form of crystal kittylitter.
The type you need looks like crushed ice with the odd little blue particles in it.
I would suggest crushing it down to get the grane size smaller than kittylitter typicaly is, as the more surface contact with the gas as it passes through, the better it will work.
It can be dried and re used by spreading it on an oven tray and cooking at about 220c for an hour or so, time depends on how thickly you spread it on the tray.
You can microwave dry it, but the oven method IMHO gets it much drier, and for refrigeration, we want it as absolutely dry as it's possible to get it!
I suggest doing this before the first use, as how dry it is when you buy it is unknown!
It will also rapidly absorb moisture from the air, so this is important!
Keep in an air tight jar once dried.
To Gas bottle adapters:
Be careful with this stuff, gas leaks could explode, best to buy these adapter hoses from ebay now days,
where you'd hope the guys selling them have made them properly!
They are an R-290 hose adapter and go from a standard gas bottle fitting to a refrigeration 1/4" SAE flare fitting which
is what all the other hoses and gages we are using in this article use.
You will obviously need 2 of these.
I did make my own by getting a welding full pressure hose from bunnings or a stove hose from big-W and cutting off the ends I didn't need and then getting a refrigeration service valve, cutting the copper pipe down to about 2.5cm, flaring the end of that so it can't blow out,
dipping the cut end of the gas hose in boiling water to soften it and pushing the flared end into it so all the copper pipe is inside the gas hose.
I then softenned an pushed about 3cm of normal 13mm garden hose over the outside of the gas hose, it should fit with some encouragement, and then put on 2 hose clamps about 1cm apart over the outside of that to clamp it all hard down and make it withstand the pressure.
I found the garden hose spread the pressure of the hose clamps and made the clamping force way more even.
I didn't find clamping with the clamps I could get was good directly on the gas hose, it was almost triangular in shape and could leak.
Best if you can buy these adapter hoses properly made though!
It is hard to get hoses to fit gas bottles without the regulater, You can use a regulater on the input side, but as the gas is flowing into the bottle on the output side, you definitely don't want a regulater involved at all!
So, all I had to do was pump gas from one bottle through sillica jel and compress it back into another bottle.
I had 2 hose sets and one set of gages, so here's how I rigged it up.
Barbecue bottle with adapters I made with a hose with no regulater, although having one would probably not hurt, and might make things safer,
to a refrigeration hose, to the input side of the compresser.
Out from the compresser to the high side of the gage set.(Red)
Middle of the gage set (Yellow)to the empty gas bottle
and the low side of the gage set (Blue)off to the vacuum pump.
Next I openned up everything except the source bottle and openned the low tap to the vacuum pump and pumped down everything including the old fridge compresser and the sillica jel
It works better if the compresser is on, but I have observed in a couple of compressers that if you get a good enough vacuum in them, they can flash over inside like a neon light and trip out your RCD.
Just something to be aware of!
Once everything was vacced down nicely, including the output gas bottle, I closed off the low valve, turned off the vacuum pump and crossed fingers and openned the gas bottle into the system!
The silica jel got warm, and the compresser started pumping, and it was all pretty easy from there, although the source bottle will get cold, and the target bottle warm, so try not to let it get too hot, as this heat directly relates to pressure, so do this outside, and perhaps even run some water over it to cool it.
I think it took 2 or 3 lots of sillica jel in the cartridge to process one 4KG bottle, and to my amazement at the time, it had pulled the smell out too!
I proved that, by rejuvinating the used sillica jel in the microwave and it stank, Really stank!!!
The original idea had been just to get the water out of the gas, but I got a bonus as wel!
So, that was the early experiment, and I have a carrier weatherwall, a had a kelvinater and now a portable air con that had lost all its gas as well as several dehumidifiers all running off this stuff, and it's working very well!
We have also done experiments with a fujitsu inverter split R-410A system on R-290, and it seems to work fine!
Add to that, some other experiments at a friends place with other r-22 splits and a mytsabishi inverter split, all doing well!
Some future experiments may include some zeotropic mixes.
some suggestions I have read about are:
By Weight:
40% butane + 60% propane will replace R-12 or R-134a.
20% CO2 + 80% propane will replace R-410a
100% propane of course will replace R-22.
Remember these gasses are flamable.
In a sealed refrigeration system they cannot burn as there is no oxygen, but a large leak could build up enough to cause an explosion.I heard recently that in Australia, it is perfectly legal to use HC refrigerents in amounts less than 150g which is equivilent to about 450g of R-22 or R-134a.
so for domestic fridges, freezers, small a/c systems it is fine.
Use larger amounts in bigger systems at your own wrisk!!!
I think, finally, that people are starting to wake up to the cartels of Dupant and others who have foisted cfcs and hfcs, etc. on the planet and that people are realising that the scare mungerring about houses exploding because of a hydrocarbon filled fridge are not the problem people thought they were!
Now we see fridges starting to adopt r600a, isobutane, basicly a high pressure isoner of butane instead of R-134a and it is working way better!
You get more cold for your buck, and the same go's for other systems, CO2, carbon di-oxide is also starting to get used and is turning out to be very effective non flamable, and totally cheap, and has a global warming potential of 1, not about 3000 like 134a!
It's downfall is that you need really thick compresser housing and pipes, but it is getting developed and I think we'll be seeing more of it in the future!
The other one that is an almost direct replacement for the old r-22 is good old propane, barbecue gas!
The differences are that it appears from the tests I've read about to be somewhere from 30 to 60% more efficient than R-22, and of course here in Australia with our brilliently conceived carbon tax (Thankfully Now abolished), R-22s price has gone mad, and add to that, it is technically phased out, so will become hard to get anyway.
R-22 is still a CFC after all!
So, why cant' we just run bbq gas directly into an air con?
Well, you can, and it will work, but it has the odorant, the deliberately added sulpher containing smell which some claim may effect motor windings and compresser parts over time, and it also may contain moisture which you really don't want in there eather!
So, when you buy proper r-290 which you certainly can, you are basicly getting a more pure gas with very little moisture and no smell.
There are many companies already selling such.
I wanted to try making some myself from a standard bottle of bunnings gas which is a damm side cheaper than all these, and definitely way cheaper than all the cfcs and hfcs!
I made, and am now re making more propperly, a filter/distilation system to do this, and it was simple as it turned out, and I hadn't even expected it to work as well as it actually did!
My original intent was to dry the gas, but to my amazement, silica jel takes up the odor incredibly well also!
By this stage I have bought some proper fridgy tools, hoses, gages, adapters etc, and a large bag of 1/4 inch shrader valves with pipe tails.
The silica jel filter I mentioned in the last article made of a hose waterring system filter cartridge was the first attempt, and it was a bit leaky, not really designed for propane bottle pressures, but it held, and it proved a point!
I now also have a couple of old compressers off old fridges with the 1/4 valves brased onto the in and out lines.
The other thing I bought amazingly cheap was a vaccuum pump, oil filled, 2 stage, for refrigeration work, and it's small, but it pumps down, it claims, to 25 microns if left long enough, and that is definitely more than good enough for our purposes here!
All this can be easily got on Ebay!
My second generation silica jel cartridge is much better, and it's made from 2 x 3/4" water hose tap adapters, the standard nylexO-ring type, They try to sell you the big ones now, with an 1" to 3/4 adapter.
I found some small brass ones with no adapter that came with a garden hose metal Y splitter at Bunnings!
I could not get hold of 1" threaded pipe or I would have used the larger ones.
Note gal pipe is not well machined on the ends, so avoid it for this project unless you have a leythe and can machine nice ends on it that will seal with the rubber washers.
I then got 2 hose filters, Bunnings call them Mexican hats, and a bit of brass 3/4 threaded rod.
Actually, you can use 2 bits of the threaded rod and a threaded joiner, Just use some good grade teflon tape to seal the join well if you want to do that!
The bigger you can make the cartridge, the better, the more silica jel you have there, the better and longer it runs before you have to change it over.
We then silver soldered a refrigeration schrader service valve with it's copper pipe removed directly onto where the hose would have connected to each of the tap adapters.
and replaced the standard rubber washers with the mexican hat versions.
So, I now had a good quallity serviceable cartridge that easily takes full gas bottle pressure with no leaks!
Next you make 2 plugs, each from about 5 squares of toilet paper and fold that length wise into about 8 so you have a long strip about 1 and a bit CM wide.
Tightly roll this up and you can roll it along a flat surface to pack it as hard as you can get it.
You should end up with a Puck-like plug that will force hard into the end of the threaded pipe.
Push the plug in so it is just inside the end of the pipe, and then fill the pipe up from the other end with silica jel until it's almost full.
Tap the pipe and the jel should pack down so you can push in the other plug on top of it.
keep Tapping the pipe and pushing the plug in until it's all tightly packed in and this plug is also just below the edge of the pipe.
You want to avoid any toilet paper getting between the pipe end and the rubber washer.
Now screw the end caps you've made on nice and tight, and you have a damn good silica jel gas drier-filter!
The toilet paper is an excellent filter and containes the silica jel and its dust, and the mexican hat strainer washers will catch any bits of toilet paper lint that might get loose.
You can re use the toilet paper plugs many times, just be careful to always put them back in the same way around. You do not want the dusty side facing the wrong way, or your compresser might end up with silica jel dust in it, Not a good thing!
Silica jel can be got very cheaply in the form of crystal kittylitter.
The type you need looks like crushed ice with the odd little blue particles in it.
I would suggest crushing it down to get the grane size smaller than kittylitter typicaly is, as the more surface contact with the gas as it passes through, the better it will work.
It can be dried and re used by spreading it on an oven tray and cooking at about 220c for an hour or so, time depends on how thickly you spread it on the tray.
You can microwave dry it, but the oven method IMHO gets it much drier, and for refrigeration, we want it as absolutely dry as it's possible to get it!
I suggest doing this before the first use, as how dry it is when you buy it is unknown!
It will also rapidly absorb moisture from the air, so this is important!
Keep in an air tight jar once dried.
To Gas bottle adapters:
Be careful with this stuff, gas leaks could explode, best to buy these adapter hoses from ebay now days,
where you'd hope the guys selling them have made them properly!
They are an R-290 hose adapter and go from a standard gas bottle fitting to a refrigeration 1/4" SAE flare fitting which
is what all the other hoses and gages we are using in this article use.
You will obviously need 2 of these.
I did make my own by getting a welding full pressure hose from bunnings or a stove hose from big-W and cutting off the ends I didn't need and then getting a refrigeration service valve, cutting the copper pipe down to about 2.5cm, flaring the end of that so it can't blow out,
dipping the cut end of the gas hose in boiling water to soften it and pushing the flared end into it so all the copper pipe is inside the gas hose.
I then softenned an pushed about 3cm of normal 13mm garden hose over the outside of the gas hose, it should fit with some encouragement, and then put on 2 hose clamps about 1cm apart over the outside of that to clamp it all hard down and make it withstand the pressure.
I found the garden hose spread the pressure of the hose clamps and made the clamping force way more even.
I didn't find clamping with the clamps I could get was good directly on the gas hose, it was almost triangular in shape and could leak.
Best if you can buy these adapter hoses properly made though!
It is hard to get hoses to fit gas bottles without the regulater, You can use a regulater on the input side, but as the gas is flowing into the bottle on the output side, you definitely don't want a regulater involved at all!
So, all I had to do was pump gas from one bottle through sillica jel and compress it back into another bottle.
I had 2 hose sets and one set of gages, so here's how I rigged it up.
Barbecue bottle with adapters I made with a hose with no regulater, although having one would probably not hurt, and might make things safer,
to a refrigeration hose, to the input side of the compresser.
Out from the compresser to the high side of the gage set.(Red)
Middle of the gage set (Yellow)to the empty gas bottle
and the low side of the gage set (Blue)off to the vacuum pump.
Next I openned up everything except the source bottle and openned the low tap to the vacuum pump and pumped down everything including the old fridge compresser and the sillica jel
It works better if the compresser is on, but I have observed in a couple of compressers that if you get a good enough vacuum in them, they can flash over inside like a neon light and trip out your RCD.
Just something to be aware of!
Once everything was vacced down nicely, including the output gas bottle, I closed off the low valve, turned off the vacuum pump and crossed fingers and openned the gas bottle into the system!
The silica jel got warm, and the compresser started pumping, and it was all pretty easy from there, although the source bottle will get cold, and the target bottle warm, so try not to let it get too hot, as this heat directly relates to pressure, so do this outside, and perhaps even run some water over it to cool it.
I think it took 2 or 3 lots of sillica jel in the cartridge to process one 4KG bottle, and to my amazement at the time, it had pulled the smell out too!
I proved that, by rejuvinating the used sillica jel in the microwave and it stank, Really stank!!!
The original idea had been just to get the water out of the gas, but I got a bonus as wel!
So, that was the early experiment, and I have a carrier weatherwall, a had a kelvinater and now a portable air con that had lost all its gas as well as several dehumidifiers all running off this stuff, and it's working very well!
We have also done experiments with a fujitsu inverter split R-410A system on R-290, and it seems to work fine!
Add to that, some other experiments at a friends place with other r-22 splits and a mytsabishi inverter split, all doing well!
Some future experiments may include some zeotropic mixes.
some suggestions I have read about are:
By Weight:
40% butane + 60% propane will replace R-12 or R-134a.
20% CO2 + 80% propane will replace R-410a
100% propane of course will replace R-22.
Remember these gasses are flamable.
In a sealed refrigeration system they cannot burn as there is no oxygen, but a large leak could build up enough to cause an explosion.I heard recently that in Australia, it is perfectly legal to use HC refrigerents in amounts less than 150g which is equivilent to about 450g of R-22 or R-134a.
so for domestic fridges, freezers, small a/c systems it is fine.
Use larger amounts in bigger systems at your own wrisk!!!