re: food bills
11 aug 1997
>...i also pick green sweet peppers, run them through my foot processer
>to slice them and then dehydrate them... ^^^^^^^^^^^^^^^^^
is this like grape smashing?
>also dehydrate some vegetables such as carrots, 5 lbs for a dollar
>and do the same thing, and add them to stews and soups....
sounds very frugal and easy to store. i wonder how the vitamins fare.
my $30 convection oven is a glass bowl with an electrified cover. the other day
the fan wouldn't start, but it was sunny outdoors, so i tied a piece of clear
plastic over the top and put some foil-faced foam on the roof of my car and
put the bowl on top of that. the temperature rose to 122 f over a couple of
hours, altho a lot of the sun didn't get into the bowl because of condensation
on the inside surface of the plastic. that's better than venting humid air at
1,000 btu per pound of water, to keep more of the roughly 1,000 btu/ft^2/day
of solar heat in the cooker, but not if it reflects sun out of the cooker...
later, it started to rain, and i'd fixed the fan, and continued cooking inside,
turning the temperature up to 180 f for a few minutes for pasteurization.
maybe i should have done that first.
a solar dryer or cooker might work like this...
the most serious mistake was making the outer container of the receiver of
plywood. we thought that the plywood would be sufficiently insulated from the
copper panel which was the receiver proper, that it would not get too hot. the
copper panel was separated from the plywood by 4" of fiberglass insulation.
nevertheless, the plywood caught fire and the unit was completely destroyed.
we suppose this is a success, of sorts...
from "a solar collector with no convection losses," (a downward-facing
receiver over a 4:1 concentrating parabolic mirror) written by
h. hinterberger and j. o'meara of fermilab, ca 1976
the convection oven is about a foot in diameter, with 3 shelves, about 2 ft^2
of drying surface. a 5 pound batch of beef jerky or dried apples might take
3 batch loadings, about 6 ft^2, so a better solar cooker might look like this,
from the side:
t t t t t is an insulated top
d t d is an insulated door, hinged at the top
d t i is a thin iron plate or "expanded metal"
<--north --- diiiiig
. g g is polycarbonate plastic
~48" . r g
. r g
from above: ~2'
. . .
this would have about . i p . r . r is a 3:1 linear parabolic
8 ft^2 of cooking . r l . . reflector made from some
surface, enough to . o a . r . aluminum foil glued to a
dry 5 lb of stuff ~4'. n t . . thin piece of sheet metal.
in one batch... . e . r .
. . .
a 1/8" iron plate might . . r . the plate might have a hole
take 1/2 hour to warm . . . in the middle to collect
up and stay warm 8 hr. ............. condensation.
the cooking temperature might be regulated by opening the door a bit.
the upper box might be made of sheet metal boxes with a few tin can spacers
and fiberglass insulation inside, with wooden studs at the outside edges.