Propane (R-290) for heat pumps? - Page 2

Xringer · 04-11-11, 07:01 AM

It makes it a lot safer to be using propane, when it stinks..

My guess is, it's most likely just about inert. Since nothing that's even slightly
reactive ( or corrosive) to metal or rubber, would be allow in the mix.

Can't have a dangerous fuel eating holes in the heater hardware..

mejunkhound · 04-11-11, 09:56 AM

FWIW, the filter dryer on a HP or AC will remove the mercaptan, so any leak will NOT have an odor.

What I've read is that the mercaptan molecule is basically an alcohol molecule with one 'O" replaced with an 'S' -- thus silica gel, activated carbon, etc. will suck mercaptn right out of the propane. For bbq propane, there are a few ppm of water in the tank, so a filter-drier is needed in the system to remove that water.

FWIW, my next DIY system will use BBQ tank refrigerant. Even the EPA has an exemption to use propane for experimental systems. One of the bigger safety concerns with propane is a warehouse fire with a lot of propane unit stored inside, not a single residential unit.

I posted a 'quiz' in the HVAC-talk.com pro technical section to see if I can elicit further comments also.

Geo NR Gee · 04-11-11, 10:13 AM

Great, thanks for the responses to my questions. I didn't think about the water in the propane tank already.

How about put a filter inline when transfering propane into the heatpump system?

Next I am going to have to research how much to charge my system.

Xringer · 04-11-11, 05:11 PM

Good info to know! I can put away my nose as a leak detection tool..

Please let us in on your "next DIY system". I'm always ready to learn new stuff!

Need those details!!

Geo NR Gee · 04-11-11, 07:18 PM

Lets say that you try experimenting with propane in a ASHP and get a leak inside the house. You cannot smell it now either because of the filter/dryer.

Then the next question is there enough propane to cause damage in a confined space?

I don't know how many pounds a normal ASHP takes, and maybe it varies on the length of the line set too?

Looks like a alarm that would kill the compressor and let you know that there is a leak.

Xringer · 04-11-11, 07:42 PM

There is some interesting info here.. Check the chart "COP vs CHARG" in this doc..

It seems like you can add more propane, but the COP stays about the same after a certain point.

Experimental Investigation OPTIMUM Charge R290

"There are many experimental investigation in the past showed that
there is a drop of total charge (40% to 60%) and running amp by 50%"..

Also just found this doc (again).. Maybe useful..

http://www.icarma.org/green/document...nal-030404.pdf

Geo NR Gee · 04-11-11, 10:00 PM

Quote:

Originally Posted by Xringer

There is some interesting info here.. Check the chart "COP vs CHARG" in this doc..

It seems like you can add more propane, but the COP stays about the same after a certain point.

Experimental Investigation OPTIMUM Charge R290

"There are many experimental investigation in the past showed that
there is a drop of total charge (40% to 60%) and running amp by 50%"..

Also just found this doc (again).. Maybe useful..

http://www.icarma.org/green/document...nal-030404.pdf

good info for sure, but understanding it is another thing. Like the following:

For safety reasons it was decided to minimize
the charge of the R-290 test unit by eliminating the refrigerant receiver. The condenser was also
modified to contain a liquid sub cooler circuit.

Xringer · 04-11-11, 11:02 PM

The charts on page 18 of that paper shows the amount of R290 used..
Looks like about 4.5 pounds. That's a pretty large system..
They used about 10 pounds of R410A..

Anyways, I have a few pounds of Propane sitting in little torch bottles down in my basement,
20 pounds on the back deck, and out in the garage there is another 20 pounds..
Plus about 15 gallons of gasoline, two cars holding about 20 gallons of gas.

I could go on, but it might make me get worried..

The Sanyo is using 4.3 pounds of R410A.. So, I'm guessing that it would need about 2 pounds of Propane.?.

I'm not sure, but it seems like 2 lbs of propane mixed correctly with the air
in a large open basement area, could lift a small house off it's foundation..
If it was ignited..

It's that fuel/air mixture, bad stuff..

If I was going to use propane, I would get rid of any open relays in the system.
Maybe SSRs could be used..

AC_Hacker · 04-11-11, 11:38 PM

Quote:

Originally Posted by Xringer

If I was going to use propane, I would get rid of any open relays in the system.
Maybe SSRs could be used..

That's what I'm doing now with my new temp controller.

-AC_Hacker

Geo NR Gee · 04-12-11, 02:47 AM

I picked up this outdoor unit and the matching indoor coil the other day. It was dirt cheap and used one summer in a vacation home. This is my experimental unit to use the propane.

It says on the label 5669G/ 200 oz. R-22. Would that be just for the outdoor unit and not including the line set and indoor unit? 5669 g (200 oz.) = 12.4980 lb.

A 5 gallon cylinger/tank can hold 20 lbs. of propane and 4.7 gallons. I also read somewhere that you would charge them by monitoring the superheat to determine the correct amount of refridgerant. Going to have to read more about that later.

It makes sense about replacing the open relays on the outdoor unit. I wonder about the fan motor?

04-11-11, 07:42 PM	#16
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Charge weight There is some interesting info here.. Check the chart "COP vs CHARG" in this doc.. It seems like you can add more propane, but the COP stays about the same after a certain point. Experimental Investigation OPTIMUM Charge R290 "There are many experimental investigation in the past showed that there is a drop of total charge (40% to 60%) and running amp by 50%".. Also just found this doc (again).. Maybe useful.. http://www.icarma.org/green/document...nal-030404.pdf

04-12-11, 02:47 AM	#20
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	I picked up this outdoor unit and the matching indoor coil the other day. It was dirt cheap and used one summer in a vacation home. This is my experimental unit to use the propane. It says on the label 5669G/ 200 oz. R-22. Would that be just for the outdoor unit and not including the line set and indoor unit? 5669 g (200 oz.) = 12.4980 lb. A 5 gallon cylinger/tank can hold 20 lbs. of propane and 4.7 gallons. I also read somewhere that you would charge them by monitoring the superheat to determine the correct amount of refridgerant. Going to have to read more about that later. It makes sense about replacing the open relays on the outdoor unit. I wonder about the fan motor? Attached Thumbnails

04-11-11, 07:01 AM	#11
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	It makes it a lot safer to be using propane, when it stinks.. My guess is, it's most likely just about inert. Since nothing that's even slightly reactive ( or corrosive) to metal or rubber, would be allow in the mix. Can't have a dangerous fuel eating holes in the heater hardware..

04-11-11, 09:56 AM	#12
mejunkhound Apprentice EcoRenovator Join Date: Apr 2011 Location: PNW Posts: 197 Thanks: 0 Thanked 47 Times in 31 Posts	FWIW, the filter dryer on a HP or AC will remove the mercaptan, so any leak will NOT have an odor. What I've read is that the mercaptan molecule is basically an alcohol molecule with one 'O" replaced with an 'S' -- thus silica gel, activated carbon, etc. will suck mercaptn right out of the propane. For bbq propane, there are a few ppm of water in the tank, so a filter-drier is needed in the system to remove that water. FWIW, my next DIY system will use BBQ tank refrigerant. Even the EPA has an exemption to use propane for experimental systems. One of the bigger safety concerns with propane is a warehouse fire with a lot of propane unit stored inside, not a single residential unit. I posted a 'quiz' in the HVAC-talk.com pro technical section to see if I can elicit further comments also.

04-11-11, 10:13 AM	#13
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Great, thanks for the responses to my questions. I didn't think about the water in the propane tank already. How about put a filter inline when transfering propane into the heatpump system? Next I am going to have to research how much to charge my system.

04-11-11, 05:11 PM	#14
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Good info to know! I can put away my nose as a leak detection tool.. Please let us in on your "next DIY system". I'm always ready to learn new stuff! Need those details!!

04-11-11, 07:18 PM	#15
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Lets say that you try experimenting with propane in a ASHP and get a leak inside the house. You cannot smell it now either because of the filter/dryer. Then the next question is there enough propane to cause damage in a confined space? I don't know how many pounds a normal ASHP takes, and maybe it varies on the length of the line set too? Looks like a alarm that would kill the compressor and let you know that there is a leak.

04-11-11, 11:02 PM	#18
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	The charts on page 18 of that paper shows the amount of R290 used.. Looks like about 4.5 pounds. That's a pretty large system.. They used about 10 pounds of R410A.. Anyways, I have a few pounds of Propane sitting in little torch bottles down in my basement, 20 pounds on the back deck, and out in the garage there is another 20 pounds.. Plus about 15 gallons of gasoline, two cars holding about 20 gallons of gas. I could go on, but it might make me get worried.. The Sanyo is using 4.3 pounds of R410A.. So, I'm guessing that it would need about 2 pounds of Propane.?. I'm not sure, but it seems like 2 lbs of propane mixed correctly with the air in a large open basement area, could lift a small house off it's foundation.. If it was ignited.. It's that fuel/air mixture, bad stuff.. If I was going to use propane, I would get rid of any open relays in the system. Maybe SSRs could be used..