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re: a spencerator
3 mar 2005
gordon richmond wrote:
>>why not simply run a pair of insulated air ducts from the interior of
>>the fridge to the outdoors, and equip the exhaust duct with a muffin fan.
>
>lower performance with less coolth storage, and ducts are larger than pipes,
>but that's not a bad idea. grainger's $31 2.6 watt 24 vdc 44 cfm 6kd73 fan
>might run 100x163/(44(32-20)) = 31% of the time to keep a fridge cold on
>20 f days from december through march in concord nh, using 19 wh/day from
>a pv battery bank vs 1 kwh from an inverter...
that knocks the natural cooling hours down from 5468 to 3675 hours (42%)
of a tmy2 year in massena ny, but it still covers november through march,
the difficult pv period.
we could squeeze 44 vertical 1-liter water bottles into a 16x24x15" deep ge
freezer compartment, with 14 ice cube trays on top, ie 104 pounds of water.
there's no need to run the fan when the return temp is much less than 32 f,
which indicates that the ice is all frozen.
10 screen 9:key off:cls
20 daystart=0'display start time (days)
30 ds=daystart*24'display start time (hours)
40 range=8760'display range (hours)
50 line (0,0)-(639,349),,b:xdf=640/range:ydf=2.69
60 for tr=-30 to 30 step 10'temp ref lines
70 line (0,349-ydf*(tr+30))-(639,349-ydf*(tr+30)):next
80 icemax=144*104'max ice storage (btu)
90 open "fridge" for input as #1:line input#1,h$
100 for h=1 to 8760'hours of typical (tmy2) year
110 input#1,month,day,hour,tdb
120 if tdb32 goto 160'don't make ice
150 if iceicemax then ice=icemax
190 if ice>0 then line (xdf*(h-ds),340)-(xdf*(h-ds),330):iceh=iceh+1'ice hours
200 if day=1 and hour=.5 then line (xdf*(h-ds),349)-(xdf*(h-ds),345)'months
210 next h
220 close #1
230 print tmin,iceh,2.6*fan/1000'fan energy (kwh/year)
-25.96 3675 5.0934
nick
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