DC generator vs DC Converter

"daestrom" wrote in message

nicksanspam@ece.villanova.edu> wrote in message Robert Gammon wrote:
Flat spiral == 7 feet diameter, 2 feet high...
... 4" high, fool.
Well, if by 'spiral' you mean some sort of serpentine.
Since the pipe is nominally 4", to get a spiral (even a 'flat spiral'), you need at least 8" where one turn crosses over the other ;-)
7' diameter coils for 100' total length means about 18 turns. Coiled in a vertical stack and then 'shoved' off to the side to spread the coils out nearly flat would take a floor space 7' wide and about 72' long (18 turns spaced about 4' apart). That's a tad much floor space for most folks ;-)

No, that can't be right :-(
7' diameter coils for 100' total length is only about 4.5 turns. Spread out in a flat spiral, that would be 7' wide and about 16' feet long. Still a fair piece of real-estate.
daestrom

daestrom wrote:

Flat spiral == 7 feet diameter, 2 feet high...
... 4" high, fool.
Well, if by 'spiral' you mean some sort of serpentine.

A mere disk, only 1 layer tall.

Since the pipe is nominally 4", to get a spiral (even a 'flat spiral'), you need at least 8" where one turn crosses over the other ;-)

.... with no crossings.

7' diameter coils for 100' total length is only about 4.5 turns. Spread out in a flat spiral, that would be 7' wide and about 16' feet long. Still a fair piece of real-estate.

I think we have some posting delay, and you musta missed this posting:
Article 111798 of alt.energy.homepower: From: nicksanspam@ece.villanova.edu Newsgroups: alt.home.repair,alt.solar.thermal,alt.energy.homepower, misc.consumers.frugal-living Subject: Re: GFX vs home brew Date: 15 Apr 2006 15:46:00 -0400 Organization: Villanova University
daestrom wrote:

... who has space for 100' of 4" pipe (vertical, coiled or otherwise).[?]

The 4" tall spiral hung under a basement ceiling would be about 7' in diameter. The 6' tall coil would occupy a 2.7' floor circle. It seems simpler to install and might have better stratification.
10 PI=4*ATN(1) 20 D=4.25'pipe OD (inches) 30 L=100'pipe length (feet) 40 DI=2'coil ID (feet) 50 DO=DI+2*D/12'coil OD (feet) 60 CI=PI*DI'inner circumference (feet) 70 NT=L/CI'number of turns 80 H=NT*D/12'coil height (feet) 90 PRINT D,DI,DO,NT,H
4.25 2 2.708333 15.91549 5.636738
10 PI=4*ATN(1) 20 D=4.25'pipe OD (inches) 30 L=100'pipe length (feet) 40 A=D*L/12'pipe area (ft^2) 50 DI=2'flat spiral ID (feet) 60 DO=2*SQR(A/PI+(DI/2)^2)'spiral OD (feet) 70 NT=12*(DO-DI)/2/D'number of turns 80 PRINT D,DI,DO,NT
4.25 2 7.006704 7.068288
Nick

Rod Speed wrote:

Robert Gammon wrote
Rod Speed wrote
Robert Gammon wrote
nicksanspam@ece.villanova.edu wrote:

A 200' version makes 82%...

But that's pretty big. How about this?

We collect all the shower water in a tank, with an infinite cold water tank next to it, then circulate the cold water through a coil in the shower tank until it all cools to the cold water temp... Then again, infinite tanks are hard to come by.

So maybe mix hot and cold fresh water to 90 F and circulate that through the coil until the shower tank drops from 100 to 95, then pump some of the 95 F fresh water back into the hot water tank and add enough cold fresh water to make the fresh mix 85, then circulate for a while, then pump some 90 F fresh water back into the hot water tank and add enough cold water to make the fresh mix 80, and so on. How can we do this automatically, on a continuous basis? We need a 20 gallon expansion tank too. Lots of pumping, but little energy, if the hot and cold supplies stay pressurized.

At some point the water needs to be heated to about 140F to kill bacteria before use in showers and baths.

No it doesnt.

Do a little research and you will find that Canada HAS such a spec.
More fool canada. You cant ignore chlorination.
Not Canada, Australia has the spec

http://www.dux.com.au/tech_domestictemp.htm
Read this page, it describes EXACTLY what happened to me at 4 years of age, why hot water heaters have this spec and why tempering valves can be a valuable addition to homes with either very your children or the elderly.

Robert Gammon wrote

Rod Speed wrote Robert Gammon wrote Rod Speed wrote Robert Gammon wrote nicksanspam@ece.villanova.edu wrote:
We collect all the shower water in a tank, with an infinite cold water tank next to it, then circulate the cold water through a coil in the shower tank until it all cools to the cold water temp... Then again, infinite tanks are hard to come by.
So maybe mix hot and cold fresh water to 90 F and circulate that through the coil until the shower tank drops from 100 to 95, then pump some of the 95 F fresh water back into the hot water tank and add enough cold fresh water to make the fresh mix 85, then circulate for a while, then pump some 90 F fresh water back into the hot water tank and add enough cold water to make the fresh mix 80, and so on. How can we do this automatically, on a continuous basis? We need a 20 gallon expansion tank too. Lots of pumping, but little energy, if the hot and cold supplies stay pressurized.
At some point the water needs to be heated to about 140F to kill bacteria before use in showers and baths.
No it doesnt.
Do a little research and you will find that Canada HAS such a spec.
More fool canada. You cant ignore chlorination.
Not Canada, Australia has the spec
http://www.dux.com.au/tech_domestictemp.htm
Read this page, it describes EXACTLY what happened to me at 4 years of age, why hot water heaters have this spec and why tempering valves can be a valuable addition to homes with either very your children or the elderly.

Irrelevant to what is being discussed, whether water MUST be heated to over 140F to kill bacteria. That clearly isnt necessary if the water is chlorinated town supply and the water isnt stored on site before use.
We dont bother to heat the cold water to over 140F before using it in the kitchen, for a reason.

wrote in message

daestrom wrote:
Flat spiral == 7 feet diameter, 2 feet high...
... 4" high, fool.
Well, if by 'spiral' you mean some sort of serpentine.
A mere disk, only 1 layer tall.
Since the pipe is nominally 4", to get a spiral (even a 'flat spiral'), you need at least 8" where one turn crosses over the other ;-)
... with no crossings.
7' diameter coils for 100' total length is only about 4.5 turns. Spread out in a flat spiral, that would be 7' wide and about 16' feet long. Still a fair piece of real-estate.
I think we have some posting delay, and you musta missed this posting:

Yah, I think so.
I was thinking of a helical arrangement, you're talking about a spiral like a phonograph groove.
Yes, it could be that small.
daestrom

dold@XReXXGFXXv.usenet.us.com wrote

Robert Gammon wrote
Not Canada, Australia has the spec
http://www.dux.com.au/tech_domestictemp.htm
I thought that was because of the peculiarity of bacteria in the wooden dams that hold the water supply for the area around Sydney, NSW.

No such animal.

Certainly not a worldwide norm.

Precisely the same type of dams are used around Sydney as are use virtually everywhere else in the first world.

phhhht......phhhht......phhhht......phhhht......phhhht......phhhht......
Hit the reject button to get the needle back.
wrote in message

In alt.solar.thermal daestrom <daestrom@no_spam_heretwcny.rr.com wrote:
I was thinking of a helical arrangement, you're talking about a spiral like a phonograph groove.
What do you do when you get to the center of the phonograph? Isn't there still at least one crossover needed?
-- --- Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5

In alt.solar.thermal Robert Gammon wrote:

Not Canada, Australia has the spec
http://www.dux.com.au/tech_domestictemp.htm

I thought that was because of the peculiarity of bacteria in the wooden dams that hold the water supply for the area around Sydney, NSW.
Certainly not a worldwide norm.
-- --- Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5

In alt.solar.thermal daestrom wrote:

I was thinking of a helical arrangement, you're talking about a spiral like a phonograph groove.

What do you do when you get to the center of the phonograph? Isn't there still at least one crossover needed?
-- --- Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5

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wrote:

In alt.solar.thermal daestrom wrote:
I was thinking of a helical arrangement, you're talking about a spiral like a phonograph groove.
What do you do when you get to the center of the phonograph? Isn't there still at least one crossover needed?

Greywater might enter and leave via the upper vertical arm of a 4" PVC T at each end of the corrugated drainpipe spiral. Fresh water might enter and leave via the ends of the Ts.
Nick

Suppose we take a shower and collect 100 F greywater in the upper part of a $30 100'x4" black plastic corrugated drainpipe coil containing 3 $20 100'x1" pieces of black plastic polyethylene pipe, with bidirectional plug flow, like this, viewed in a fixed font like Courier:
shower in | --------->--------------------------------> hot water to shower | | Tl | --------- sewer --------- | | Tg | out | 120F | | | | | | | | | ^ | | | | | | | | | |1" |4" | | tank | | | | | | water | | | | | | heater | | | | | | | | | | | | | | | | | | | | | |---- | | | | | | 55F | --------- P --------- | ---- Tc | -----------------| <- |-------------------< cold water supply ----
Now we disable the water heater and run a slow, low-power pump P (eg Grainger's $120 4PC86 (Taco 003-BC4-2) 1/40 HP 120V 0.43A pump) if Tg - Tl < 5 F and Tg - Tc > 5 F, and enable the water heater again when Tg - Tc < 5 F...
Is this a GFX-Star? It's hard to tell from the website description.
20 UPIPE=78.5'U-value of 10' section of 3 1" pipes (Btu/h-F) 30 CFRESH=1.25*8.33'thermal capacitance of 10' of fresh water (Btu/F) 40 VGREY=10*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 CSERIES=CFRESH*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 89'simulate 10 min shower every 90 minutes 110 IF M>9 GOTO 220'rest vs shower 120 IF SHOWER <100 GOTO 150 140 PRINT 400+M;"'";M,TG(9) 150 TGT=TG(0)'save original Tg(0) for later Tg(1) calc 160 TG(0)=(100*CFRESH+TG(0)*(CGREY-CFRESH))/CGREY'move greywater in 170 FOR S=1 TO 9'pipe section (9<->fresh water in and greywater out) 180 TGP=TG(S)'buffer 190 TG(S)=(TGT*CFRESH+TG(S)*(CGREY-CFRESH))/CGREY'move greywater down 200 TGT=TGP'buffer 210 NEXT S 220 IF (TG(0)-TF(0))>5 OR TG(0)<60 GOTO 290'no pumping 230 PUMP=PUMP+1'pump in fresh water at bottom 240 IF SHOWER>49 THEN HEAT=HEAT+CFRESH*(TF(0)-55)'gain from gw 250 FOR S=0 TO 8'shift fresh water up 260 TF(S)=TF(S+1) 270 NEXT S 280 TF(9)=55'move cold water in at the bottom 290 FOR S=0 TO 9'rest 300 TFINAL=(TF(S)*CFRESH+TG(S)*CGREY)/(CFRESH+CGREY) 310 TF(S)=TFINAL+(TF(S)-TFINAL)*EXPF'new fresh temp (F) 320 TG(S)=TFINAL+(TG(S)-TFINAL)*EXPF'new grey temp (F) 330 NEXT S 340 NEXT M 350 NEXT SHOWER 360 SHOWERGY=50*10*CFRESH*(100-55)'50 showers with no GWHX (Btu) 370 PRINT HEAT,SHOWERGY,HEAT/SHOWERGY,PUMP
time gwout (min) (F)
0 55.50439 1 55.66506 2 55.83802 3 56.02375 4 56.22276 5 56.43565 6 56.66306 7 56.90572 8 57.16441 9 57.43995
231607 234281.3 .9885854 1458
Looks good on paper, with 98.9% heat recovery :-)
Nick

nicksanspam@ece.villanova.edu wrote:

Suppose we take a shower and collect 100 F greywater in the upper part of a $30 100'x4" black plastic corrugated drainpipe coil containing 3 $20 100'x1" pieces of black plastic polyethylene pipe, with bidirectional plug flow, like this, viewed in a fixed font like Courier:
shower in | --------->--------------------------------> hot water to shower | | Tl | --------- sewer --------- | | Tg | out | 120F | | | | | | | | | ^ | | | | | | | | | |1" |4" | | tank | | | | | | water | | | | | | heater | | | | | | | | | | | | | | | | | | | | | |---- | | | | | | 55F | --------- P --------- | ---- Tc | -----------------| <- |-------------------< cold water supply ----
This is so very very close to a GFX Star it isn't funny

What the Dr argues for is a el-cheapo electric water heater that is used solely as a storage tank. The inlet to the pump is thru a check valve that ties to the drain connection of the water heater/storage tank. Hot out of the heat exchanger then goes to TWO places.
1. To a tempering valve to limit scald risk. the other input of the tempering valve is the output of the normal hot water supply (electric, NG, LP, or same inputs tank less)
2. Cold in on the water heater/storage tank.
Hot Out of the water heater/storage tank goes to Cold in on the normal water heater.
Nick's figures and the Power-Pipe folks argue that the heat recovery is equivalent to a 12-18KW electric heating element (for a 60 inch GFX). In testing of the the GFX done at at least a couple of universities, they found that the upper heating element in an electric water heater NEVER TURNED ON in ANY of their testing.
The heat recovery of a GFX when used in this configuration jump 15-20 percentage points and becomes an almost level 65-75% Course we will have 2KW/day losses in that storage tank. But with a CONSTANT input ot the normal Hot water heater of 85-90 F, it will merely LOAF along to deliver the HOT water needed.
One of the reasons for the higher heat recovery is that the flow rate thru the coil LEAPS. The Taco pumps will move up to 20Gal/hr depending on model to 20 feet. More realistically a Taco 006 or Taco 008 will delvier upwards of 10Gal/hr at 10 feet of height. Now we have 2x-4x MORE flow thru the coil than is flowing in the greywater. The graphs on the GFX web site illustrate what happens with higher coild flow rates.
GFX Star controls the pump via one of two methods
a. Timer - showers at KNOWN times EVERY day
b. Differential temperature controller -sensors on coil and inlet to the heat exchanger (GFX or Nick's) will trigger the pump when temp difference exceeds a set point - i.e. 2 or 3 degrees

Robert Gammon wrote:

Suppose we take a shower and collect 100 F greywater in the upper part of a $30 100'x4" black plastic corrugated drainpipe coil containing 3 $20 100'x1" pieces of black plastic polyethylene pipe, with bidirectional plug flow, like this, viewed in a fixed font like Courier:
shower in | --------->--------------------------------> hot water to shower | | Tl | --------- sewer --------- | | Tg | out | 120F | | | | | | | | | ^ | | | | | | | | | |1" |4" | | tank | | | | | | water | | | | | | heater | | | | | | | | | | | | | | | | | | | | | |---- | | | | | | 55F | --------- P --------- | ---- Tc | -----------------| <- |-------------------< cold water supply ----
This is so very very close to a GFX Star it isn't funny

I'm still not clear on that, after talking with Carmine again. One diff might be beneficial stratification in the greywater drainpipe, vs full mixing in a conventional greywater tank. At any rate, with 98.9% heat recovery, we might heat 50K Btu/day of water with 550 Btu/day, eg a 7 watt night light burning 24 hours per day :-)

Nick's figures and the Power-Pipe folks argue that the heat recovery is equivalent to a 12-18KW electric heating element (for a 60 inch GFX).

Dr. V got US Customs to sieze Power Pipes at the border, based on a theft-of-trade-secrets charge, but they seem to have gotten around that.

In testing of the the GFX done at at least a couple of universities, they found that the upper heating element in an electric water heater NEVER TURNED ON in ANY of their testing.

We also discussed some testing techniques that were biased against GFX.

The heat recovery of a GFX when used in this configuration jump 15-20 percentage points and becomes an almost level 65-75%

Maybe a lot more, with greywater plug flow.

One of the reasons for the higher heat recovery is that the flow rate thru the coil LEAPS. The Taco pumps will move up to 20Gal/hr depending on model to 20 feet. More realistically a Taco 006 or Taco 008 will delvier upwards of 10Gal/hr at 10 feet of height. Now we have 2x-4x MORE flow thru the coil than is flowing in the greywater.

That isn't part of my scheme, but another circulating pump could increase the velocity through the coil and the conductance inside the coil...

GFX Star controls the pump via one of two methods
a. Timer - showers at KNOWN times EVERY day
b. Differential temperature controller -sensors on coil and inlet to the heat exchanger (GFX or Nick's) will trigger the pump when temp difference exceeds a set point - i.e. 2 or 3 degrees

That's quite different. No timing for me, and I'd turn on the pump when the gw-fw temp diff at the output is LESS than 5 degrees.
Nick

Power-Pipe now has a US web site that gets them around the customs issue.
The pump with differential temperature control is the secret to higher recovery rates. Flow rate thru the coil in excess of flow rate of greywater will more efficiently transfer heat to the potable water.
Actually you could take this a step further and use a water storage tank intended for solar applications. It has an internal heat exchanger, and you could route a working fluid thru Nick's, a GFX, or a Power-Pipe that was NOT water for higher heat capacity.
nicksanspam@ece.villanova.edu wrote:

Robert Gammon wrote:
Suppose we take a shower and collect 100 F greywater in the upper part of a $30 100'x4" black plastic corrugated drainpipe coil containing 3 $20 100'x1" pieces of black plastic polyethylene pipe, with bidirectional plug flow, like this, viewed in a fixed font like Courier:
shower in | --------->--------------------------------> hot water to shower | | Tl | --------- sewer --------- | | Tg | out | 120F | | | | | | | | | ^ | | | | | | | | | |1" |4" | | tank | | | | | | water | | | | | | heater | | | | | | | | | | | | | | | | | | | | | |---- | | | | | | 55F | --------- P --------- | ---- Tc | -----------------| <- |-------------------< cold water supply ----
This is so very very close to a GFX Star it isn't funny
I'm still not clear on that, after talking with Carmine again. One diff might be beneficial stratification in the greywater drainpipe, vs full mixing in a conventional greywater tank. At any rate, with 98.9% heat recovery, we might heat 50K Btu/day of water with 550 Btu/day, eg a 7 watt night light burning 24 hours per day :-)
Nick's figures and the Power-Pipe folks argue that the heat recovery is equivalent to a 12-18KW electric heating element (for a 60 inch GFX).
Dr. V got US Customs to sieze Power Pipes at the border, based on a theft-of-trade-secrets charge, but they seem to have gotten around that.
In testing of the the GFX done at at least a couple of universities, they found that the upper heating element in an electric water heater NEVER TURNED ON in ANY of their testing.
We also discussed some testing techniques that were biased against GFX.
The heat recovery of a GFX when used in this configuration jump 15-20 percentage points and becomes an almost level 65-75%
Maybe a lot more, with greywater plug flow.
One of the reasons for the higher heat recovery is that the flow rate thru the coil LEAPS. The Taco pumps will move up to 20Gal/hr depending on model to 20 feet. More realistically a Taco 006 or Taco 008 will delvier upwards of 10Gal/hr at 10 feet of height. Now we have 2x-4x MORE flow thru the coil than is flowing in the greywater.
That isn't part of my scheme, but another circulating pump could increase the velocity through the coil and the conductance inside the coil...
GFX Star controls the pump via one of two methods
a. Timer - showers at KNOWN times EVERY day
b. Differential temperature controller -sensors on coil and inlet to the heat exchanger (GFX or Nick's) will trigger the pump when temp difference exceeds a set point - i.e. 2 or 3 degrees
That's quite different. No timing for me, and I'd turn on the pump when the gw-fw temp diff at the output is LESS than 5 degrees.
Nick