# Re: GFX vs home brew - Page 7

Posted by Solar Flare on April 17, 2006, 12:12 am

So you are saying "Better nick's wife batting him around than ours"?

Posted by nicksanspam on April 17, 2006, 9:24 am

Mine objected to 300 55 gallon drums on the lawn. When I moved 200 into
a greenhouse and the rest into the basement, that was OK. Go figure.

Fat plumbers in grimy jeans come in and say "Gimmie a 45 degree Thomson
slidearm and a couple of 16" vertical Whittakers with the purple nibs."

Do what you do best. Lots of people can build things that don't leak.
I'd like to know why the energy that flows into the gwhx is less than
the energy that flows out during a shower, in that simulation.

My 4th HP digital camera stopped working. They seem fragile. Otherwise,
you might see me stretching the curves out of 300' of 1" pipe with
a tree and a pickup truck.

Nick

Posted by nicksanspam on April 17, 2006, 10:06 am

Changing the heatflow from linear to a more accurate exponential (two caps
equalizing voltage through a resistor) made little difference...

20 UPIPEx.5'U-value of 10' section of pipe (Btu/h-F)
30 CFRESH=1.25*8.33'thermal capacitance of 10' of fresh water (Btu/F)
40 VGREY*3.14159*(2/12)^2'volume of 10' of greywater (ft^3)
50 CGREY=VGREY*62.33-CFRESH'thermal capacitance of 10' of greywater (Btu/F)
60 CSERIESRESH*CGREY/(CFRESH+CGREY)'caps in series (Btu/F)
70 RC=CSERIES/UPIPE'combined time constant (hours)
80 EXPF=EXP(-1/60/RC)'exponential factor
100 FOR SHOWER = 1 TO 100'simulate showers
110 FOR M=0 TO 59'simulate 10 min shower + 50 min rest
120 IF M>9 GOTO 250'rest vs shower
130 IF SHOWER <100 GOTO 170
140 RHEAT=RHEAT+CFRESH*(100-TF(0))'reheat energy
150 GLOSS=GLOSS+CFRESH*(TG(9)-55)'greywater heat loss
160 PRINT 400+M;"'";M,TF(0),RHEAT,TG(9),GLOSS
170 TF(0)=TF(1)'move fresh water up
180 TG(0)=(100*CFRESH+TG(0)*(CGREY-CFRESH))/CGREY'move greywater in at the top
190 FOR S=1 TO 8'pipe section (9<->fresh water in and greywater out)
200 TF(S)=TF(S+1)'move fresh water up
210 TG(S)=(TG(S-1)*CFRESH+TG(S)*(CGREY-CFRESH))/CGREY'move greywater down
220 NEXT S
230 TF(9)U'move cold water in at the bottom
240 TG(9)=(TG(8)*CFRESH+TG(9)*(CGREY-CFRESH))/CGREY'move greywater down
250 FOR S=0 TO 9'rest
260 TFINAL=(TF(S)*CFRESH+TG(S)*CGREY)/(CFRESH+CGREY)
270 TF(S)=TFINAL+(TF(S)-TFINAL)*EXPF'new fresh temp (F)
280 TG(S)=TFINAL+(TG(S)-TFINAL)*EXPF'new grey temp (F)
290 NEXT S
295 NEXT M
310 NEXT SHOWER
320 SHOWERGY*CFRESH*(100-55)
330 PRINT RHEAT,SHOWERGY,1-RHEAT/SHOWERGY

0       94.38332      58.48365      71.9481       176.4721
1       92.75861      133.8847      72.28975      356.5016
2       91.17551      225.7697      72.71021      540.9092
3       89.71318      332.8812      73.10856      729.4646
4       88.41459      453.5143      73.48615      921.9516
5       87.28408      585.919       73.84426      1118.167
6       86.30738      728.4934      74.18405      1317.921
7       85.46612      879.8273      74.50663      1521.034
8       84.74309      1038.69       74.81306      1727.338
9       84.12328      1204.006      75.10433      1936.674

1204.006     4685.625     .7430426

Why 1204 Btu in and 1936 out?

Nick

Posted by nicksanspam on April 17, 2006, 12:11 pm

20 UPIPEx.5'U-value of 10' section of pipe (Btu/h-F)
30 CFRESH=1.25*8.33'thermal capacitance of 10' of fresh water (Btu/F)
40 VGREY*3.14159*(2/12)^2'volume of 10' of greywater (ft^3)
50 CGREY=VGREY*62.33-CFRESH'thermal capacitance of 10' of greywater (Btu/F)
60 CSERIESRESH*CGREY/(CFRESH+CGREY)'caps in series (Btu/F)
70 RC=CSERIES/UPIPE'combined time constant (hours)
80 EXPF=EXP(-1/60/RC)'exponential factor
90 FOR SHOWER = 1 TO 100'simulate showers
100 FOR M=0 TO 59'simulate 10 min shower + 50 min rest
110 IF M>9 GOTO 270'rest vs shower
120 IF SHOWER <100 GOTO 160
130 RHEAT=RHEAT+CFRESH*(100-TF(0))'reheat energy
140 GLOSS=GLOSS+CFRESH*(TG(9)-55)'greywater heat loss
150 PRINT 400+M;"'";M,TF(0),RHEAT,TG(9),GLOSS
160 TF(0)=TF(1)'move fresh water up
170 TGT=TG(0)'save original Tg(0) for later Tg(1) calc
180 TG(0)=(100*CFRESH+TG(0)*(CGREY-CFRESH))/CGREY'move greywater in at the top
190 FOR S=1 TO 8'pipe section (9<->fresh water in and greywater out)
200 TF(S)=TF(S+1)'move fresh water up
210 TGP=TG(S)'save original Tg(s) for later Tg(s+1) calc
220 TG(S)=(TGT*CFRESH+TG(S)*(CGREY-CFRESH))/CGREY'move greywater down
230 TGT=TGP'prepare for Tg(s+1) calc
240 NEXT S
250 TF(9)U'move cold water in at the bottom
260 TG(9)=(TGT*CFRESH+TG(9)*(CGREY-CFRESH))/CGREY'move greywater down
270 FOR S=0 TO 9'rest
280 TFINAL=(TF(S)*CFRESH+TG(S)*CGREY)/(CFRESH+CGREY)
290 TF(S)=TFINAL+(TF(S)-TFINAL)*EXPF'new fresh temp (F)
300 TG(S)=TFINAL+(TG(S)-TFINAL)*EXPF'new grey temp (F)
310 NEXT S
320 NEXT M
330 NEXT SHOWER
340 SHOWERGY*CFRESH*(100-55)'if no GWHX (Btu)
350 PRINT RHEAT,SHOWERGY,1-RHEAT/SHOWERGY

0       93.72946      65.29199      67.76752      132.9418
1       91.50189      153.7785      68.01705      268.4818
2       89.30461      265.1443      68.32899      407.2698
3       87.3519       396.8427      68.61366      549.0221
4       85.71924      545.5411      68.89086      693.6606
5       84.37411      708.2456      69.15711      841.0716
6       83.2604       882.5468      69.41382      991.1554
7       82.33891      1066.443      69.66134      1143.817
8       81.58043      1258.237      69.90021      1298.965
9       80.95963     *1456.495      70.13091     *1456.516

1456.495      4685.625      .6891568

Ah. Much better with buffering in lines 170, 210, and 230.
The effectiveness dropped to 69%, but it still beats a GFX,
esp. for baths, with no large vertical space requirement.
And the pipe conductance might end up larger, with greywater
vs liquid manure, and warm greywater bouyancy (not simulated)
might also help.

Thanks, daestrom :-)

Nick

Posted by nicksanspam on April 18, 2006, 9:38 am
... 5 vs 3 100' pipes only raised the effectiveness from 68 to 77%.
A 200' version makes 82%... 200' of 4" drainpipe would wrap around
the lower 3' of an 86" diam x 48" tall STSS heat storage tank.

15 DIM TF(20),TG(20)
20 UPIPEx.5'U-value of 10' section of pipe (Btu/h-F)
30 CFRESH=1.25*8.33'thermal capacitance of 10' of fresh water (Btu/F)
40 VGREY*3.14159*(2/12)^2'volume of 10' of greywater (ft^3)
50 CGREY=VGREY*62.33-CFRESH'thermal capacitance of 10' of greywater (Btu/F)
60 CSERIESRESH*CGREY/(CFRESH+CGREY)'caps in series (Btu/F)
70 RC=CSERIES/UPIPE'combined time constant (hours)
80 EXPF=EXP(-1/60/RC)'exponential factor
90 FOR SHOWER = 1 TO 100'simulate showers
100 FOR M=0 TO 59'simulate 10 min shower + 50 min rest
110 IF M>9 GOTO 270'rest vs shower
120 IF SHOWER <100 GOTO 160
130 RHEAT=RHEAT+CFRESH*(100-TF(0))'reheat energy
140 GLOSS=GLOSS+CFRESH*(TG(19)-55)'greywater heat loss
150 PRINT 400+M;"'";M,TF(0),RHEAT,TG(19),GLOSS
160 TF(0)=TF(1)'move fresh water up
170 TGT=TG(0)'save original Tg(0) for later Tg(1) calc
180 TG(0)=(100*CFRESH+TG(0)*(CGREY-CFRESH))/CGREY'move greywater in at the top
190 FOR S=1 TO 18'pipe section (19<->fresh water in and greywater out)
200 TF(S)=TF(S+1)'move fresh water up
210 TGP=TG(S)'save original Tg(s) for later Tg(s+1) calc
220 TG(S)=(TGT*CFRESH+TG(S)*(CGREY-CFRESH))/CGREY'move greywater down
230 TGT=TGP'prepare for Tg(s+1) calc
240 NEXT S
250 TF(19)U'move cold water in at the bottom
260 TG(19)=(TGT*CFRESH+TG(19)*(CGREY-CFRESH))/CGREY'move greywater down
270 FOR S=0 TO 19'rest
280 TFINAL=(TF(S)*CFRESH+TG(S)*CGREY)/(CFRESH+CGREY)
290 TF(S)=TFINAL+(TF(S)-TFINAL)*EXPF'new fresh temp (F)
300 TG(S)=TFINAL+(TG(S)-TFINAL)*EXPF'new grey temp (F)
310 NEXT S
320 NEXT M
330 NEXT SHOWER
340 SHOWERGY*CFRESH*(100-55)'if no GWHX (Btu)
350 PRINT RHEAT,SHOWERGY,1-RHEAT/SHOWERGY

0       96.58958      35.51103      62.44146      77.4842
1       95.26726      84.79071      62.58688      156.4826
2       93.96446      147.6357      62.76867      237.3738
3       92.78384      222.7741      62.93455      319.9923
4       91.76805      308.4892      63.09611      404.293
5       90.9036       403.2055      63.25129      490.2096
6       90.16348      505.6282      63.40093      577.6842
7       89.52875      614.6602      63.54522      666.6613
8       88.98529      729.3508      63.68448      757.0885
9       88.52072      848.8789      63.81895      848.9157

848.8789      4685.625      .8188334

Nick

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 Re: GFX vs home brew AstickfortheMUL... 04-14-2006
 Re: GFX vs home brew Robert Gammon 04-14-2006
 Re: GFX vs home brew nicksanspam 04-14-2006
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