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Imagine a refridgerator with a thumb button on the handle
where you grip tp open it that releases the negative ressure
or re-evacuates the fridge of air (produces a vacuum) in the
fridge... Not only would this give the refridgerator greater
effeciency (heat transfer-wise) but also keep any food
within
it from going bad...(I think...)
The fridge would have to re-fridgerate for a while to bring the
temperature back down after someones opens it, but after it
does this it could re-vacuum the fridge...
halfbaked?
Nitrogen Fridge
http://www.halfbake...a/Nitrogen_20Fridge A related idea: replace air with inert gas [wiml, Jun 14 2002, last modified Oct 04 2004]
Siemens "vacuumTechnology" fridge
http://www.gizmag.c...50b04f86a9-90474673 [xaviergisz, Sep 05 2013]
Norcold Vacuum Seal
https://www.google....eid=chrome&ie=UTF-8 Slightly reduced pressure to ensure a good seal. [csea, Sep 06 2013]
[link]
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It would be harder for a vacuum fridge to cool things down. It would be like a giant thermos. Once they were cold, though, would the vacuum help keep them that way? I don't think so: the walls of the fridge will have to be cold, and the amount of heat lost to the environment when the door is closed depends on the temperature of the walls of the fridge. The vacuum fridge *would* be able to weather a power outage better, though, as long as you didn't want to open it... |
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Actually, this idea is back to front; the best sort of fridge would be a tank of chilled brine (2 centigrade)with a circulating stirrer - this would cool any food placed in it really fast. The technique is used in commercial food packaging plants.
But make sure the packets are hermetic, unless you like salt with everything. |
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Just don't put pop bottles in there. Come to think of it, don't seal anything up before putting it in there. |
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No good for frequently used fridges (almost any family's fridge). You wouldn't want to evacuate it after every time the kid gets a snack or drink out. |
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But probably good for storing your winter's supply of pemican. Unless you've got a constant pemican snacker in your wigwam. |
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why would it be harder for a vacuum fridge to cool things down? i would think that in a vaccum, if anything, there would be a lesser need for cooler temperatures anyway... |
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all these other "issues", they can be dealt with through design... |
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Make the door to the 'fridge clear and put two of those full sleeves in the lower part of the door. When the user wants something, they use the full sleeves to put the item into one of the airlocks on the side of the 'fridge. |
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From the link: "reduce the air pressure by 300
millibars. Siemens claims that the system can keep
food fresh up to five times longer " |
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I find that implausible. The only effect of reducing
air pressure by 30% will be to accelerate water loss. I
doubt that bacterial or fungal growth will be all that
much impeded by a slightly lower pressure. |
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I wonder if food would stay fresh longer because of the reduced oxygen content in the air. I remember years ago there was talk of using some kind of molecular filter to remove oxygen from fridges for that purpose. |
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Of course if your meat is in a sealed bag I'm not sure how oxygen levels outside the bag would make a differece. |
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I once owned an RV which had a refrigerator that
incorporated a "vacuum seal" which operated
when the door was closed. It seemed to replace
or augment the usual magnetic seal, and one could
hear the pump operate briefly when the door was
closed. |
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It took more than the usual force to pull the door
open. One could see the vinyl sealing strip being
compressed as the door closed. |
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I'll try to dig up a [link.] |
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It'd be easy to integrate a valve or even just a cam into the handle to release the pressure differential before trying to open the door. |
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Maybe the lower thermal conductivity of the partial vacuum could be offset by energetically circulating what air there was inside the compartment? |
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Most fridges/freezers available now already do
circulate the air inside them. At least here in the
colonies. |
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