Alternative Refrigeration and Refrigerants
 

Since we are a motley band of fiends bent on having our own peculiar way with refrigeration technology, I thought it would be fitting to open a brain-storming, no holds barred thread for discussing refrigeration alternatives (no limits here).

To kick things off, I found a very interesting paper called, "New, Natural and Alternative Refrigerants", available RIGHT HERE.

After I read this paper, it went straight away into my horde of alternative energy documents, which has now swelled to a plump 7GB.

I'd really like to know your thoughts.

-AC

To summarize, hydrocarbons show the most promise for DIY use.

In my professional life, AIR was the refrigerant of choice. Air cycle, centrifugal compressor @ 30,000 rpm.

Kinda hard to do even in a corporate environment, but sure is 'green', eh?

If I can find another 2T scroll someplace for 'cheap', I'll do a bbq propane with only normal filter dryer and see what happens. TXV, no orifice or cap tube.

I'm looking forward to seeing the details of that project.

-AC

You're right, but the paper illuminates so many interesting aspects to the field of refrigeration... some are practical, some are currently not.

I came across this paper, because I was searching for another paper, that recognized the efficiency of Propane (R290) but also described the potential for even higher efficiency of another refrigerant, Propylene (R1270). Turns out that R1270 (AKA: Propylene, Propene & Methylethylene) never got it's day in the sun because it was considered to be too expensive for large-scale manufacturing. Well, how could there be a more inviting reason to hack together a system that used R1270? I mean it's organic, exotic (it has been identified to exist on a moon of Saturn), efficient and industry has turned its back on it because it is too expensive! It's got it all!! BTW, and I might be wrong, but I think that Propylene is now being used in applications that formerly used MAPPS gas.

I also came across, either in this paper or another one, the wide-scale, successful deployment of Butane (R600) in small refrigerators.

And I encountered cautions regarding maximum prudent amounts of HC that should be deployed in low-infiltration occupied spaces.

But who knew that there was such a thing as Magnetic Refrigeration? I don't currently see an application for near absolute zero refrigeration in my house, but what an amazing concept!

-AC

Propylene is only expensive at the consumer level. The gas is in high demand as a staple feedstock of the plastics industry. There is an imbalance between this high demand and the natural supply (from oil and gas wells), so the refineries make propylene by reacting propane with a catalyst, yielding propylene and hydrogen. Due to the economic rise of China and India, demand for plastic products has and will continue to increase drastically.

As we speak, the petroleum industry leaders are racing each other to build propylene plants. The larger demand for propylene (and ethylene) coupled with the low cost of natural gas makes for a high-stakes scramble to the top. Due to the fracking craze, the oil giants have found undiscovered treasure in their old wells that are no longer producing oil.

Compared to the processes currently employed to manufacture "modern" refrigerants, the proplylene process is like mixing cool-aid. It has to be much less expensive. The best thing about it is, it works as a drop-in replacement for R22, even better than propane.

I remember all those homework exercises that began with "Propylene (or ethylene, or whatever) is adiabatically compressed from something kPa to .......... calculate H".

All these years I thought such gasses existed for no other purpose than to torture students. Well, ethylene was at least useful if you were the oracle at Delphi, but getting high and having visions isn't a useful point of interest in HVAC.

The two processes I'd love to see progress in are:

1. Stirling Cycle (refrigeration and CHP)

2. Dessicant Systems (both PCM and liquid-based heating/cooling/dehumidification)

R433b (ES22a) is 95% R290 and 5% R1270. It is tuned to work well for air conditioning applications. There's also R433a and R433c (greater percentage of R1270) that are designed to work better for refrigeration and heat pump applications.

So what are your thoughts about and how might you proceed on the Stirling cycle + CHP? I don't think anyone on ER has made a serious inquiry into that.

-AC