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marx290 · 03-17-13, 04:23 PM

I do have some concerns about dangers associated with R-290. (I use filtered BBQ Propane like many hobbyists, but calling it R-290 is close enough I suppose.) The work I've done with it before was in a pretty open air garage where, with some common sense and small charge quantities, I wasn't too at risk of an ignitable mixture. Now, in the cupboard under the sink could be quite a different matter and a few ounces of propane accidentally released, although unlikely, could possibly explode I suppose. Even with a low pressure kill switch and combustable gas alarm, it's probably not worth the risk.

I have a Type I EPA certification for refrigerants (never used it), so there are a couple of refrigerants I could get a hold of however, I have to say I'm not a fan of the proprietary halogenated refrigerants because of their expense, polluting nature of synthesis and global warming potential. Of course, the hydrocarbons might replace the need for most of them if it weren't for the flammability issue. It seems the HC refrigerants are doing just that in certain industries in some other countries, but that is in well tested equipment. For the experimental hobbyist, those flammability dangers are perhaps a greater danger. I will heed your warning and appreciate your suggestion. In cases where I don't feel I can use propane safely, I will consider using R-134a. I read a post somewhere of yours AC_Hacker, describing a refrigerant leak resulting in the denser gas sinking down a set of steps into a basement or something. Have you or anyone you know ever had an unsafe experience using propane as a refrigerant? Ignition even?

In regards to refrigerant control; I played with capillary tubes for a while, but quickly found them to be very limiting. I had a good deal of success using a brass flow control to control refrigerant control, just as the "Temperature Man" used to manually adjust a flow valve in ice plants, I could play with the orifice size and adjust it for a given set of conditions. It is certainly not as reliable as a capillary tube (I would imagine flash gas probably deteriorates the innards of the valve), and a manual valve obviously doesn't self regulate like a TXV or EXV, but it's a hell of a lot of fun and serves to teach the hobbyist what an automatic valve cannot. More of a needle valve with greater precision in control is something I'm looking for.

03-17-13, 04:23 PM	#5
marx290 Vapor Compression Goon Join Date: Mar 2013 Location: Portland, OR Posts: 63 Thanks: 11 Thanked 22 Times in 11 Posts	I do have some concerns about dangers associated with R-290. (I use filtered BBQ Propane like many hobbyists, but calling it R-290 is close enough I suppose.) The work I've done with it before was in a pretty open air garage where, with some common sense and small charge quantities, I wasn't too at risk of an ignitable mixture. Now, in the cupboard under the sink could be quite a different matter and a few ounces of propane accidentally released, although unlikely, could possibly explode I suppose. Even with a low pressure kill switch and combustable gas alarm, it's probably not worth the risk. I have a Type I EPA certification for refrigerants (never used it), so there are a couple of refrigerants I could get a hold of however, I have to say I'm not a fan of the proprietary halogenated refrigerants because of their expense, polluting nature of synthesis and global warming potential. Of course, the hydrocarbons might replace the need for most of them if it weren't for the flammability issue. It seems the HC refrigerants are doing just that in certain industries in some other countries, but that is in well tested equipment. For the experimental hobbyist, those flammability dangers are perhaps a greater danger. I will heed your warning and appreciate your suggestion. In cases where I don't feel I can use propane safely, I will consider using R-134a. I read a post somewhere of yours AC_Hacker, describing a refrigerant leak resulting in the denser gas sinking down a set of steps into a basement or something. Have you or anyone you know ever had an unsafe experience using propane as a refrigerant? Ignition even? In regards to refrigerant control; I played with capillary tubes for a while, but quickly found them to be very limiting. I had a good deal of success using a brass flow control to control refrigerant control, just as the "Temperature Man" used to manually adjust a flow valve in ice plants, I could play with the orifice size and adjust it for a given set of conditions. It is certainly not as reliable as a capillary tube (I would imagine flash gas probably deteriorates the innards of the valve), and a manual valve obviously doesn't self regulate like a TXV or EXV, but it's a hell of a lot of fun and serves to teach the hobbyist what an automatic valve cannot. More of a needle valve with greater precision in control is something I'm looking for.