Propane (R-290) for heat pumps?

[oil pan 4]

I am very sure the house we are moving into with the new 3 ton air conditioner is an R-410 machine. I am very interested in the R-290 conversion.

[AC_Hacker]

Originally Posted by oil pan 4

I am very sure the house we are moving into with the new 3 ton air conditioner is an R-410 machine. I am very interested in the R-290 conversion.

Dear Oil Pan,

The volume of refrigerant in a 4-Ton air conditioner is quite large, and if there was a leak, the consequences could easily be a first class disaster.

If every single component of your refrigerant system is outside of your house envelope, and you can house your air conditioning system in a separate shed, have no walls in common with your house, and your refrigeration equipment is located a safe distance from your home, and you are able to supply chilled (or heated) water for your cooling (or heating),to your home, perhaps only then should you consider a conversion.

Besides, you can get R410 fairly easily and you wouldn't need to replace the compressor, lubricant, heat exchangers, metering device, etc. (basically the entire system).

Why exactly do you want to convert to R290??

-AC

[oil pan 4]

All the leak problems I have seen so far have been in or near the compressor or isolated to the out side condenser unit its self. Break down of lines was always was on older units due to compressor vibration, weathering, being repeatedly crashed into by a riding lawn mower or because a dog had been peeing on it for years.
I have only herd of air handlers leaking due to improper install.
When they did leak it was always a slow leak, I would throw a 200psi nitrogen charge and it would slowly leak down.

It sounded that the R-290 was a drop in replacement, other than replacing the filter dryer and oil. Kind of like doing a R-12 to R-134a retrofit.

Its a 3 ton unit I believe and wouldn't that contain less than 5 or 6 lb of refrigerant? I usually only work on enormous systems usually charged with 70 to hundreds of pounds of R-134a when full.

I can get as much bulk R-410, 404, 134a and 22 as I want, I have the CFC and HCFC handlers certification.

If it will move the same amount of heat, with less energy I am interested.

[AC_Hacker]

Originally Posted by oil pan 4

If it will move the same amount of heat, with less energy I am interested.

It will do that.

Sounds like you have a bit of experience with this kind of machinery.

You know where to get B-B-Q gas... So what is stopping you?

-Ac

[oil pan 4]

BBQ gas isn't R-290.
I read some where that propane fuel had up to 10% butane and a few percent of other hydrocarbons in it.

[AC_Hacker]

Originally Posted by oil pan 4

BBQ gas isn't R-290.
I read some where that propane fuel had up to 10% butane and a few percent of other hydrocarbons in it.

That is true, it does have some amount of butane.

But there have been people on this forum that have had lasting success with the stuff.

-AC

[gtojohn]

I thought r209 is a drop in for r22. Very close to the same pressure temperatures. So new metering device. If its a piston that can be super quick. Sounds like you know your refrigeration. One of the reasons I found this site was the r209 info.

[AC_Hacker]

Originally Posted by gtojohn

I thought r209 is a drop in for r22. Very close to the same pressure temperatures. So new metering device. If its a piston that can be super quick. Sounds like you know your refrigeration. One of the reasons I found this site was the r209 info.

It is R290, not R209... it's like the difference between fog and fgo.

If you have already an R22 system it is pretty much a drop in replacement. You don't even need to change the metering device.

oil pan 4 is starting off with a R410 system. I haven't tried this conversion, but the characteristics of R290 and R410 are not close. Different compressors, different lubricants, different HX sizes, different metering device sizes, different P-V curves.

There is someone on this forum who hasn't tried it either, who say it will work great.

That person isn't me.

-AC

[jeff5may]

Originally Posted by oil pan 4

BBQ gas isn't R-290.
I read some where that propane fuel had up to 10% butane and a few percent of other hydrocarbons in it.

The 10% figure is an industry standard. In the USA, at gas stations and walmarts everywhere, the propane in cylinders is pretty pure. The only contaminant besides the stink oil that gets into the percent range is propylene. In the refrigeration circuit, propylene acts even more like r-22, due to its higher molecular weight. Butane and other natural gas ingredients are distilled out to the ppm range at the refinery.

[AC_Hacker]

Originally Posted by jeff5may

The 10% figure is an industry standard. In the USA, at gas stations and walmarts everywhere, the propane in cylinders is pretty pure. The only contaminant besides the stink oil that gets into the percent range is propylene. In the refrigeration circuit, propylene acts even more like r-22, due to its higher molecular weight. Butane and other natural gas ingredients are distilled out to the ppm range at the refinery.

I actually went to a local LPG gas distributor, and personally talked to the manager who told me that they guaranteed that the gas was at least 90% propane and that other gases, "such as Butane", could also be included, but that the percentage of Propane was usually higher than 90%.

So it sounded to me like market forces could vary the mix, and that the ultimate purpose, as far as they were concerned, was for fuel, and as long as their product could be used as fuel, and they stayed within their specified guidelines, everything was good.

I have read reports from China that indicated that mixing in a small percentage (around 8%) of butane could improve propane as a refrigerant.

Ethyl mercaptan, the stink gas, C2H6S, has sulphur and "might" combine with any water in the system, to produce an acid which could cause corrosion.

Vlad did some interesting work using two refrigeration filters in series, on the line he used to gas his system, and said that the resulting gas was odorless.

-AC