re: solar assist for hot water heater - would it work?
27 mar 1996
lorne collicutt wrote:
>1. is it possible to have a solar cell on your roof help lower
>the $ of keeping water in your electric hot water tank hot?
sure. how about this?
clear corrugated . i t i .
polycarbonate--> . . .
. . <--pv panel .
. . .
note this is in the roof, not on the roof. to me, solar panels on the
roof make no sense today, economically. altho if they were up there
anyway, one might add a 2:1 reflector under an extra layer of glazing,
and trickle some water over them.
but it seems better to use 4' x 12' polycarbonate "shingles" for the roof with
stanford ovshinsky's new 5%-efficiency electroplated "pv shingles" in long
strips under the rafters, and put some insulation up in the ridge peak,
with a long galvanized water tank up there under the insulation, with no
insulation underneath the tank, so the tank is heated by solar hot air
from the shingle-pv cavity, when the tank water temp is low, and when the
tank is warm enough, some sort of damper with a bimetallic spring opens
near the top of the cavity to let the pvs run cooler. in a cold climate,
this steep south transparent roof could also make hot air for the house
under the insulated attic floor, and perhaps some daylighting. and it
would cost less than a conventional roof.
>2. are the purchase and installation costs and headaches worth the $?
no. it's much more cost-effective to replace the pvs with some dark-colored
insulation board, today. of course, one could heat water with pv elecricity,
while throwing away 90% of the rest of sun's power as heat :-)
the fourteenth-century byzantine saint sabas pretended to be deaf,
dumb and mad--a pretense that he kept up with great skill for 20 years.
yet he could not escape the danger of fame. on visiting cyprus, he reacted
to the attention given to him by large crowds by suddenly sitting down
on a dung heap, where he spent the remainder of the day. the emperor of
constantinople sought to persuade him to accept the office of patriarch,
but sabas refused. he refused even to be ordained as a priest. when the
emperor attempted to have him ordained by stealth, sabas fled; keen to
have the saint remain, the emperor had to chase after him, beg his
forgiveness, and solemnly promise to make no further attempts to
interfere with sabas's saintly ways.
from _holy madness_, by georg feuerstein