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Originally Posted by ericb  Well now, it has come alive again... About the vibration I don't have any exact data. I do know, however, that the stirling cooler uses CO2 as an intermediate, which is in a thermosyphon around the chamber. |
Yes, read that, only later I started pondering about this concept, in a different context, 'what if I build a box/system from scratch, where does the 'evaporator' go, how does it connect to the Stirling'....of course, I can use any heat-transfer system, even use (energy-consuming) electric pumps and ordinary fluids (but of course, for the most extreme temperatures (and worst-case fluid/solid expansions!), fluids have their limits (I believe the glycol-dilution table (eutectica) ends at -60F). Btw, what would the smallest fluid pump option be in this context? I guess the largest variety can be found in the PC-(water)cooling industry? (gambling a bit with glycol-compatibility of course)
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This means that the cooled CO2 slowly drops down by gravity (higher density when it's colder), and the slightly warmer CO2 on top is going back to the cooling. This is the reason for the 12 degree slope restriction. I can imagine that an excess of vibration will not help the process. On the other hand, it is (widely?) used in vehicles.... and they all vibrate. Also, in the Past, research has been done about putting a Stirling engine in a car. It's responsiveness kept it from getting any further at the time. I think that, at the least it will keep running, but the cooling will be worse.
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Lack of responsive/reactiong-time is the territory of hybrids....
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on the PS: last year i bought one from the NL office of Global Cooling (yes, I am in NL too). They do sell it as an "Engineering Sample". If it's still on the website, it should still be available.
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Never saw any product for sale on the .NL site, not now either....was it really actively marketed online, or did you ask by phone? (send them another email yesterday, again no response)
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It ain't exactly a bargain, though. As I recall, it was about €485 excl. BTW.
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Not a bargain as in the Coleman-sell-out context, but the higher-end compressor fridges are not much cheaper....only thing they offer more, in that price range, is an eutectic element....a shame that this isn't even optional with the Coleman/Twinbird.... (yes, I know that with a Stirling, the thermodynamics don't benefit from eutectica, but it would make the box more portable, plus absolutely silent at night) I should also note though that, being Dutch, I have never bought any compressor fridge above 130 euro, and I am on #5 now, after 4x Kissmann/IndelB TR825....
) (the 3 with Kissmann half-hermetic all need a refill, but none is younger than 15-20 years, and only one cost more than 50 euro's, so they have no blame....
) (and that 130 was only recently, for a Waeco RHD-85, BD35F/eutectic (currently being tested, lovely research project, given all the optional Danfoss settings/wiring....
) (the fun part with eutectic fridges, at least those who have the evaporator hidden/untouchable under the eutectic element, is that some owners, clearing out their basement, test it too shortly, and then think/state that it is broken....
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