re: planck and christmas
28 dec 1995
>>...not too many people, eg on interstate 50 through southern nevada and utah.
> just for remembrce sake, since i suffer amnisia sort of, if you go from
>chicago to san f i think you take 30 highway no, and if you go south
> direction l.a you take ....?, 5 runs north to south.southward for spherical
>totally forgot, those are the days.
ok, i'll go look at the road atlas in my car, out on the street on this
cold sunny day in brooklyn, with some leftover snow. where are my shoes...?
looks like route 80 will get you from sf thru reno, salt lake city, cheyenne,
omaha, chicago, toledo, cleveland, and all the way to new york city...
route 35 seems to be a large e-w bisector of our contintent, running from
thunder bay, ontario (where it calls itself route 81), down the northwestern
edge of lake superior to duluth, minnesota, thence through minnehopeless,
des moines, kansas city and wichita (after a westwards arabesque), and on
to oklahoma city, dallas, waco, san antonino, then (alias route 85) further
on to monterrey in mexico, then on down through mexico city to acapulco...
where it is probably warmer now.
>>>>a lot of farmers around me (i have more sheep and goats than people
>>>>for neighbors) are actually very good mechanics, rebuilding their
>>>>tractor engines every year, welding, etc. they could probably make
>>>>a lot more money fixing cars.
>>>. . that is why they have subsides, few billions around the second war.
>>i think these guys are mostly unsubsidized. they farm for a hobby,
>>after their full time job is over. one i knew was a telephone lineman.
> oh, i got it, it is the agribusiness that got the subsides.
yes, i think so. individuals don't get much. $50/year for 5 acres?
depending on what you choose to not grow. but you have to have a track
record of growing things first, before you can make money not growing things.
>>> by the way do you have basic understanding of geometry or do you need
>>> basic help.
>>i need help.
> then i can send you lesson one soon, though i am self know very little
> really, you do know nothing at all. i will feel very stupid
>sending you a staff you know already. are you making fun of me, little
>me. do you have admonson amy book.
no, i really am mostly ignorant, and often confused by geometry, as in
school mechanics problems ("how much coriolis force will the ant feel
on his left leg, as he tries to crawl east on the ball that the child
is spinning around his head on a string at the equator?") i think this task
will be nearly impossible, with only email text communication. good.
i don't have that book.
>>happy happy christmas.
> i was suspended and time escaped...
christmas was like that for me too, with a 1 day flu and a 102 fever.
> do you know nick consellatey a funny guy i know who have mention you to
> me. oh that nick is in a big cave similar in proportion to my cave.
no, i don't know him... you guys live in caves?
i have a some friends who lives in a solar cave, with an annual electric
resistance backup heating bill of $58. they get ready for winter in
late november, by closing some windows to make the temperature rise in
their slow house from 70 f to 72 f, over two weeks.
suppose cavepersons had had glass...
. | up
r10 earth at . south ==>
55 degrees f .
/ g if the enterprising caveperson had insulated
rc / g the inside of the cavern with leaves and
------------------g w g mud, until, say, rc = 10, and the daytime
| .----- . temp of the cavern had been 65 degrees f
| 20 x 20' cavern | . and the nighttime temp had been 55, and
| 10' tall | . he or she had desired to warm the cave
| | . for, say, 5 days without sun, with an
--------rf-------- . average sunnytime steady-state floor
|vaulted -- stone | . temp of, say 90 f, and mammoth skins
| ----- ----- | t . piled on top of the floor to make
|--- floor ---| . a sunny day r-value of rf (which
. . . skins could be moved aside to
. rc . . . decrease the r-value of the floor
. g during sunless times), how much
note that since .rc g glass area, ag, would have been
the upper edge of the . g ag needed, and what would rf and
glass is lower than the . g the average floor thickness t
bottom of the floor, the floor .aa g have had to have been,
stays warm during sunless times, . g ignoring the clerestory
because of this igloo-like heat trap. . g cave window, w?
(how did the caveperson insulate around . g
the edge of the floor?) g south ==>
the daily heatloss of the cavern would have been .
lday = (8 hours)(1200 ft^2/r20)(65-55) ~ 5k btu. 32 f outside temp
during sunny times, the sun would shine onto the .
absorbing surface aa, assumed equal to ag, and some .
heat would be lost thru rc to the earth underneath... .
the daily net heat resulting from each square foot of .
glass might have been on the order of .
eg = 1000 - 8(90-32)/r1 - 8(90-55)/r20 .
sun glass loss absorber back loss .
= 500 btu/ft^2/day .
so keeping the cavern warm might have required only about .
10 ft^2 of glass... a 3.16 x 3.16' single-glazed window, or .
an early sliding-glass door... .
the mammoth-skin floor resistance would want to have been about .
rf = (90-65)(400 ft^2)/(5000/8) = r-16. .
during sunless days, the skins would be moved around or a trapdoor .
in the floor would have been opened to reduce this, to get more heat .
out of the floor... .
assuming the floor would have had a minimum r-value of 1, per square foot .
(both sides), the required heat transfer rate would have been about 5000/8 .
btu/hour, from 800 ft^2 of floor, which leads to a minimum temperature .
differential, after 5 days, of about 1 degree f.
so if the masonry had held about 22 btu/ft^3/degree f, the floor thickness
might have wanted to be about
t = (5 days)(5000 btu/day)/((90-66)(22)(400 ft^2)) = .12'
other modern improvements might include making the whole thing above ground,
including some bottles filled with water in the floor, making the absorbing
surface a parabolic reflector, and making the floor a wall.
>i try to read the rest. i have a solar calculator which i use very rarly
>but it gives me the feeling i own free machine, if only we
> can get a house like that we will be in our way to send politican
> home to learn how to cook french food.
when houses and fuel are free, the politicians will need retraining, eh?
ok. here's more...
/*ball park solar closet house design*/
ta=32; /*average december ambient temp (f)*/
tcold=-10; /*coldest december ambient temp (f)*/
sun=1000; /*average amount of sun falling on sunspace glazing (btu/ft^2/day)*/
dl=6; /* average number of hours of sun per day*/
tr=68; /*room temp (f)*/
l=12; /*house length (ft)*/
w=8; /*house width (ft)*/
h=8; /*house height (ft)*/
ch=2000; /*thermal mass of house (lb h2o)*/
aw=2*(l*w+l*h+w*h); /*outside surface area (ft^2)*/
rw=23; /*r-value of outside surface of house (ft^2-deg f-hr/btu)*/
dhl=24*(tr-ta)*aw/rw; /*daily house heat loss (btu)*/
dhlc=24*(tr-tcold)*aw/rw; /*heat loss on coldest day (btu)*/
av=1*2.; /*damper area (ft^2)*/
df=av*16.6*sqrt(h); /*damper factor*/
printf("%.1f%s\n",tss," f, min sunspace temp to supply average daily heat");
printf("%.1f%s\n",cfmshm, " cfm, avg ss-house airflow on a day with min sun");
cc=4000; /*pounds of water in solar closet*/
atm=200; /*thermal mass surface area (ft^2)*/
rtm=2./3.; /*thermal mass surface r-value (ft^2-deg f-hr/btu)*/
ntuf=atm/rtm; /*see 1993 ashrae hof, p 3-4*/
lc=4; /*closet length (ft)*/
wc=4; /*closet width (ft)*/
hc=8; /*closet height (ft)*/
rc=20; /*r-value of solar closet surface (ft^2-deg f-hr/btu)*/
printf("%.1f%s\n",tcm," f, min closet temp to heat house on avg day w/o sun");
printf("%.1f%s\n",cfmchm," cfm, avg closet-house airflow after 5 day w/o sun");
printf("%.1f%s\n",tr-dhl/ch," f, min house temp at night, w/o closet heat");
printf("%.1f%s\n",tcs," f, min water temp to heat house 5 days w/o sun");
/*find avg closet cfm to keep house warm on coldest day w/o sun*/
printf("%.1f%s\n",cfm," cfm, avg c-h airflow on coldest day, at 5d clo temp");
/*find average daily solar closet loss (btu) at that steady-state temp*/
ac=1.*2.; /*solar closet damper area (ft^2)*/
dfc=16.6*ac*sqrt(h); /*solar closet damper factor*/
uc=dcl/dl; /*min clo gain/hour (btu) on an average day, to maintain 5d temp*/
qc=pow(dfc*dfc*uc,1./3.); /*min clo airflow (cfm) to maintain 5d temp*/
eff=exp(-ntuf/qc); /*heat exchanger efficacy for solar closet*/
dt=uc/qc; /*temp difference from top to bottom of closet (f)*/
tbot=tcs+dt*eff/(1-eff); /*temp at bottom of closet (f)*/
ttop=tbot+dt; /*temp at top of closet (f)*/
printf("%.1f%s\n",tbot," f, avg daytime steady-state temp at bottom of closet");
printf("%.1f%s\n",ttop," f, avg daytime steady-state temp at top of closet");
printf("%.1f%s\n",cfmsha," cfm, avg ss-house airflow on an average day");
printf("%.1f%s\n",cfmsca," cfm, avg ss-closet airflow on an average day");
/*find min glazed area for min ss temp, while providing house and closet heat*/
printf("%.1f%s\n",ag," ft^2, min glazed sunspace area for 5d storage");
78.5 f, min sunspace temp to supply average daily heat
304.6 cfm, avg ss-house airflow on a day with min sun
72.2 f, min closet temp to heat house on avg day w/o sun
28.4 cfm, avg closet-house airflow after 5 days w/o sun
58.4 f, min house temp at night, w/o closet heat
96.2 f, min water temp to heat house 5 days w/o sun
61.5 cfm, avg c-h airflow on coldest day, at 5d clo temp
97.8 f, avg daytime steady-state temp at bottom of closet
102.9 f, avg daytime steady-state temp at top of closet
91.8 cfm, avg ss-house airflow on an average day
211.7 cfm, avg ss-closet airflow on an average day
44.7 ft^2, min glazed sunspace area for 5d storage