On 30/04/2008, Apptech <apptech@paradise.net.nz> wrote:
> E --
>       |
>      \/
>
> >>  50kWsec = 0.833 KWminutes=0.0138 KWhrs=0.1 cents per
> >> cooldown
>
> >>  Also, as you say, I doubt that all of the air fully
> >> exchanges in a
> >>  typical door opening. The thermal mass of all the other
> >> stuff in there
> >>  will do two things: 1) make it so that there is less air
> >> 2) make the
> >>  compressor have to turn on and off less. Other than
> >> that, it will not
> >>  change the average amount of energy needed per cooldown,
> >> as whatever
> >>  cooling effect you get from the cold food has to be
> >> recuperated by the
> >>  compressor.
>
>       |
>      \/
>
> > So the problem is much worse for empty refrigerator?
> > One more reason to keep it always full of beer :)
>
> Not really.
> Most refrigerators would have only a small proportion
> occupied by food, or beer.
>
> A dedicated packing with bottled beer would probably not
> reach 50% fill.
>
> Cans stacked diameter to diameter can approach Pi/4 packing
> ~= 78% but only if the cooled space is an exact multiple of
> can dimensions in all 3 dimensions.
>
> If you close pack the cans in staggered rows max fill
> increases to - ah - I knew there was a reason they discussed
> packing in Chemistry all those years ago  ... aaagh ... Pi/6
> x sqrt(3) =~ 90.7%. Round down somewhat as above. Probably
> really lucky to get more than about 80%.
>
> Note that the 90.69...% is optimum for an infinite sheet of
> beer bo... er circles. Use a mix of bottle sizes and the
> packing may be lower and will never be higher.
>
> Store your beer in plastic bags and you could do better.
>
> You'll be sorry ...
>
>         http://mathworld.wolfram.com/CirclePacking.html
>
> ______
>
> Also
> If you maintain a high beer fill ratio this is liable to
> promote a high churn and the penalty for cooling large delta
> mass of beer is far worse than cooling the same volume of
> air. Filling it with beer only works if it doesn't get
> imbibed. To save  money adopt the double effective strategy
> of storing only emergency beer supplies in the fridge and
> drinking someone else's beer whenever possible.
>
>
>         Russell
>


 The other trick is buy beer from the chiller and put it in the fridge
before it warms up!

RP
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