The Homemade Heat Pump Manifesto

[AC_Hacker]

Originally Posted by Mobile Master Tech

Although a hydrocarbon refrigerant system should be safe when designed and serviced properly...

MMT,

There's a lot to ponder here...

There are certainly dangers associated with using hydrocarbon refrigerants, as you have pointed out. The situation you have described was bad, but could have been much worse.

I have read reports of R134a igniting. The conditions required for R134a to burn are not casual, but it can ignite and the heat of combustion is extremely high, and the products of combustion are quite toxic.

As BradC has demonstrated very well, an experimenter or DIY person can take safeguards to minimize the risk when working with organic refrigerants... The greatest danger of all is when a HVAC tech who thinks a system contains synthetic refrigerants, treats the system as such and doesn't take the special precautions that organic refrigerants require. That situation must never occur.

Included with my tank of R-22a were about two dozen stickers to be used on equipment, that clearly spelled out that organic refrigerants were present.

However, stationary refrigeration systems are subject to much less stress and fatigue. Barring an accidental or assault on the system, if an indoor system does develop a leak, it is usually very slow. Slow enough that natural infiltration will carry away leaked refrigerant so that critical build-up is very unlikely.

My greatest quarrel with synthetic refrigerants is the long-term damage they do to the atmosphere. R-22 & R-12 were replaced because they were doing great damage to the ozone layer. An ozone hole opened up over Australia, and cancers and cataracts were increasing at an alarming rate. The US stood by and did nothing... Then the ozone layer developed a hole over Kennebunkport, Maine, which was the town where the vacation home of the Bush family was located. Very shortly after this happened, the US suddenly decided to employ non-ozone degrading refrigerants (& propellants).

The refrigerants currently in use do not degrade the ozone layer, but they do have very serious and very long lasting global warming potential.

I know that some people don't consider themselves to be 'environmentalist', and ignore and reject information and concerns regarding the environment. I find this attitude to be very perplexing... it's as if it would be possible to 'op into' or 'opt out of' the environment.

But as the global warming situation makes it clearer that our options are not unlimited, greater use will be made of hydrocarbon refrigerants.

I'm seeing movement in that direction in Australia and also in Europe.

One of the most reasonable solutions (in use in the UK) is to remove the hydrocarbon containing parts of the equipment to a separate and preferably non-combustible equipment shed, and to use a non-flammable heat conveyor like water to bring the heat energy into the dwelling space.

Regarding multiple refrigerants, I know that work is being done on it and I have seen good documentation on the XtremeSystems Forums site.

They have some very advanced folks doing amazing things there. Their focus is on extreme chilling of CPU cores and they don't have much patience with anybody wanting to heat a house... but there is loads of useful, applicable information to be found.

Best,

-AC