yet another wide-eyed, theoretical speculation :-) SOLAR.KnowledgePublications.com

yet another wide-eyed, theoretical speculation :-)
29 jan 1996
this one in basic and metric, written for norman saunders, pe, 
whose pc is a trash-80 :-)

nick

10 'ball park solar closet house design
20 '
30 '                         l ~10 m
40 '           -------------------------------
50 '          |                    rw ~6      |          ta ~2 c
60 '          |                               |
70 '          |        th ~20 c             rw|
80 '          |                               |
90 '       w  |                               |
100 '   ~ 10m |rw                             |
110 '         |                       lc  rw  |
120 '         |                   ------------|
130 '         |           rw  wc | cc   atm   |
140 '          ------------------------acg----|
150 '                    |    tss ~25 c       |
160 '                     ----------asg-------
170 '
180 ta=2'average december ambient temp (c) in philadelphia
190 sun=2.9'avg of sun falling on sunspace glazing (kwh/m^2/day)
195 gr=.2'ground reflectivity (fraction)
196 sun=1000*(sun+gr*sun)'increased sun with ground reflection (wh/m^2/day)
200 dl=6'average number of hours of sun per day
210 th=20'house temp (c)
220 l=10'house length (m)
230 w=10'house width (m)
240 h=5'house height (m)
250 aw=2*(l*w+l*h+w*h)'outside surface area of house (m^2)
260 rw=6'average r-value of outside surface of house (m^2-deg c/w)
270 dhlc=24*(th-ta)*aw/rw'daily conductive heat loss of house (wh)
280 vh=l*w*h'house volume (m^3)
290 ach =.2'average house air infiltration rate (air changes per hour)
300 dhla=24*ach*vh/3*(th-ta)'daily infiltration heat loss of house (wh)
310 kwh=100'miserly monthly electric consumption of house (kwh)
320 dhg=kwh*1000/30'daily internal heat gain of house (wh)
330 dhl=dhlc+dhla-dhg'daily total heat loss of house (wh)
340 print int(dhlc/100+.5)/10, "(kwh), daily conductive heat loss of house"
350 print int(dhla/100+.5)/10, "(kwh), daily infiltration heat loss of house"
360 print int(dhg/100+.5)/10, "(kwh), daily internal heat gain of house"
370 print int(dhl/100+.5)/10, "(kwh), daily net heat loss of house"
380 shcfm=1'sunspace to house fan (m^3/s)
390 tss=th+dhl/dl/(shcfm*1200)'average daytime sunspace temperature (c)
400 print int(tss*10+.5)/10,"(c), average daytime sunspace temperature"
410 tsg=.92'solar transmission of sunspace glazing (fraction)
420 rsg=.16'r-value of sunspace glazing (m^2-deg c/w)
430 asg=dhl/(sun*tsg-dl*(tss-ta)/rsg)'required sunspace area (m^2)
440 print int(asg*10)/10, "(m^2), required sunspace area"
450 nd=24'number of 233 liter drums full of water in solar closet
460 cc=nd*.233'm^3 of water in solar closet
470 atm=nd*2.32'total surface area of water containers (m^2)
480 rtm=.12'thermal mass surface r-value (m^2-deg c/w)
490 ntuf=atm/rtm'see 1993 ashrae hof, p 3-4
500 lc=4'closet length (m)
510 wc=2'closet depth (m)
520 hc=2'closet height (m)
530 ac=2*(lc*wc+lc*hc+wc*hc)'total surface area of solar closet (m^2)
540 acg=2*3'closet air heater glazed area (m^2)
550 ang=ac-acg'total unglazed area of solar closet (m^2)
560 sccfm=1'solar closet air heater fan (m^3/s)
570 'find closet water temp, after a long string of average days, with some sun
580 ein=sun*tsg*tsg*acg'solar energy into air heater (wh/day)
590 num=ein+dl*tss*acg/rsg+(24-dl)*ta*acg/rw+24*th*ang/rw'num. of tw formula
600 den=6*acg/rsg+18*acg/rw+24*ang/rw'denominator of tw formula
610 tw=num/den'steady-state closet water temperature
620 eff=exp(-ntuf/(sccfm*1200))'heat exchanger efficacy for closet
630 qc=ein/dl-(tw-tss)/rsg'net daytime heatflow into closet (w)
640 dt=qc/(sccfm*1200)'daytime air temp diff from top to bottom of closet (c)
650 tbot=tw+dt*eff/(1-eff)'temp at bottom of closet (c)
660 ttop=tbot+dt'temp at top of closet (c)
670 print int(10*tbot+.5)/10,"(c), avg daytime air temp at bottom of closet"
680 print int(10*tw+.5)/10,"(c), steady-state closet water temperature"
690 print int(10*ttop+.5)/10,"(c), avg daytime air temp at top of closet"
700 schcfm=1'solar closet-house fan (m^3/s)
710 twm=th+dhl/24/(schcfm*1200)
720 print int(10*twm+.5)/10,"(c), min water temp to heat house on day w/o sun"
730 d=cc*1164*(tw-twm)/dhl
740 print int(10*d+.5)/10,"(days), number of sunless days of thermal storage"

 28.8  kwh, daily conductive heat loss of house
 14.4  kwh, daily infiltration heat loss of house
  3.3  kwh, daily internal heat gain of house
 39.9  kwh, daily net heat loss of house
 25.5  c, average daytime sunspace temperature
 17.1  m^2, required sunspace area
 73.8  c, avg daytime air temp at bottom of closet
 69.1  c, steady-state closet water temperature
 76    c, avg daytime air temp at top of closet
 21.4  c, min closet water temp to heat house on day w/o sun
  7.8  days, number of sunless days of thermal storage