Revisiting greywater in a drum

[[email protected]]

I am working on a batch water heater concept that uses a horizontal
pond of water that is about 6 inches deep; 4X8ft in plan; insulated on
bottom and sides; double glazed on top.

With a 15 hour time constant losing water at night? :-(

...a flat spiral of PEX or PE pipe is immersed in the pond (like your
greywater heat exchanger). The immersed pipe stores 2 or 3 or more
gallons of hot water that comes out first when the tap is turned on.
...Based on a little simulation with TMY weather, I think it might
work pretty well just as described in Florida type areas --horz
surfaces get a lot of radiation, and ambients are high. In more
northern places (like here) it needs some help. I have a 4X6
prototype with 90 ft of 3/4 PE immersed in it (probably not enough)--
it has an insulated lid that also acts as a reflector when open.

Sounds interesting, if the cover moves automatically.

Anyway, the variation would be to take your 50 gallon drum with the
immersed pipe coils and use it as a batch heater -- i.e. put it in a
glazed box with a reflector. Kind of like a conventional batch
heater, but without the expense and hassle of a pressurized tank
(which seem to be getting hard to come by at a reasonable cost).

Better, but an indoor greywater heat exchanger might reduce
the energy needed for water heating by 80% or more...

Nick

 

[wmbjk]

My problem is my house layout. My ensuite shower is at the opposite corner
of the house and it takes between 2-3 minutes to get hot water to flow. With
1/2 copper pipe, that is a lot of wasted hot water left in the pipe when it
is done, not to mention the cold wastage. I have drained this plumbing
before and many, many gallons come out.

How much is "many, many"? Ten perhaps? You need to be more careful
when making stuff up. Even five gallons would mean you're draining
about 500 feet of pipe. Let's deduct a hundred in case the pipe takes
an indirect route, leaving 400 feet diagonal. An 80,000 sq. ft square,
something less if it's a rectangle. Do you have a scooter to get
around this house, or is it possible that "many, many gallons"
translates to "less than one"?

Wayne

 

[m II]

How much is "many, many"? Ten perhaps? You need to be more careful
when making stuff up. Even five gallons would mean you're draining
about 500 feet of pipe.

He's not making it up. He did the original plumbing, so what do you expect?
Being the self professed expert on all things that affect the human experience,
Gymmy (Gymy, Gymn, Gymmie, etc, etc, etc,) Bob has no need of reference
materials of ANY sort. He does things the way they SHOULD be done, the 'experts'
be damned.

Keep in mind, he has many, many motion sensors throughout his house, telling the
main computer what to do and when. It is astounding that mere plumbing would
defeat him.


mike

-----------
My 'GymyBobism' collection...updated daily:
=========================================
## some '#' bracketed text added for clarification ##
## all cut and paste, NO modifications of ANY kind ##
## 100 % Pure GymyBob. Accept no substitutes! ##



We need less morons like another clone of Moron II here.
## My fifteen minutes of FAME! ##


Your car alternator will charge your car batery up to 15.4 volts in cold
weather.

NTSC redefined it slightly off 60Hz so that power supply ripple
will move on the screen (two slightly black bands that scroll
up/down your screen

Portable humidifiers do not typically use heat to evaporate the water. The heat
from the room is used.

You sure spent a lot of time trying to convince me you don't knwo what I am
talking about...LOL

You babies are a blast like RC toys to play with!

Voltage does not indicate state of charge well.

At 11.6 volts a 12v battery is about 50-70% charged still.

Polish solar panels are what americans called "flashlights"

We have to consider the DC/DC inverter in between that can act as a step up for
current since the batteries cannot use the high voltage from the panels in full sun.
##unaware what flooded cell batteries do to solar panel output voltage##

There should be subsidies for solar panels but control of prices to boot.

Propane will disapate and freeze when it evaporates.

Gasoline is not nearly as volatile as hydrogen.

When I use pot I imagine everythging is perfect.

Perhaps you should only spoeak on things you know something about.

Many people have browsers that economize the download

Just another threading error creating confusion

Learn how to thread or sit back and watch for a few years.

Try to stay on topic and on thread too bean brain.

Perhaps try Outlook Express or another browser that knows how to thread
posts.

Ohhhh. that's how it works here. If you put the boost to as many
concepts,ideas and posters as possible it makes you a better person?

Bottom posting was the was in the 70s and 80s before threading browsers were
available cheap like OE

Another Forte Agent person that doesn't understand threading.

You use Mozzilla and haven't learned to thread.

Try Outlook Express so you can understand threading maybe.

I have been noticing many threading errors everywhere on Usenet lately.

People with OE don't seem to have the petty problems with subject
lines changing, intermingled posts and downloading binary files with mixed
posts, random pieces and many other problems all the nonOE people have.

Bottom posting has been obsoletely by threading browsers.

Forwarding does not include headers.

Call your damn ISP and tell them your browser is multiple posting.

90% of the people in America have never operated a computer.

Let's say youre solar cell was trying to put out
14.3 volts DC and you stuck a 10 ohm meter in series with a charged 13.8
volt DC battery.

Your troll was too obvious. Try to engage the mark in conversation first so
there is, at least, some stake, like friendship for the person listening.
When the friendship is well developed then attack. Not too obvious at first
or you will lose your audience. This will enhance your troll points.

I think outside opinions are worth much more than sales hype from the
company that made the product.
## Referring to *factory* charging specifications for the batteries they make ##
This is good to know. However I tend to go by the manufacturer's information.
They provide the warranty.

This is power grid induction through capacitive proximity

You can get fooled with another ground in the house finding it's way back to the
transformer neutral.

A thought I have is rain water from a roof on a three story home through a
micro-turbine.

Setback thermostats only work efficiently for small differentials, dependant
on the time duration.

Breakers are good for one time usage of one fault and then they need to be
replaced for any warrantied usage.

If the breaker interupts a fault, it should be replaced.No warranty will
honoured after that.

This newsgroup is full of selfproclaimed experts like you.

I don't have a link at this time

There are no hydrogen molecules in water and the oxygen in water isn't
flammable either.

Water is inert and contains no energy to be used. Get some basic chemistry
first.

Quite simply put, for some of the boneheads here.

Most conclude their isn't many knowledgeable people here. I do.

NiCads and NiMh batterries are designed to take a current charge forever.

Oh yeah, I can charge a battery and use it six months later fully charged.
The nicads will be cooked because you keep them on charge, just in case you
need them but when you remember them six months later they are cooked and
won't last 5 minutes in the camera.

It takes a complete idiot to deny they can short out all by themselves.
Three, loose in a bag can short themselves out.
## referring to AA batteries doing the physically impossible ##

Did they have electricity back in 1994?

I have been around so long with this stuff I believe I invented the diode in
1941 but I am not familiar with the solar panel usage requirements of them.
(no P & N substrate explanations please. I wrote the GE manual...LOL)

NOTE: do not pass ground wires through metal holes or cable clamps with two
screws on a metal surface.

There is **NOT*** enough energy in a lightning bolt to power your house for
more than an hour...if that. Do the math.
The figures escape me but let's say it puts out a roughly MWatt of power for
100 nanoseconds?
100 x 10-9 x 1 x 106 / 3600 (sec/hr) = 0.0027 wH
oooops.... Wouldn't light your home for a 1/2 second.
OK..OK.. multiply the figures time 100 or 1000. Now it would light a 100W
bulb for 1 second.

The IEEE-232 standards were never followed or known by many.

Fossil fuels are still renewable and being cxreated as we speak.

Children are venerially created.

If you want to discuss this then fine, otherwise go **** yourself like your
mother did.

Can you let go of my dick before it explodes on ya, goofball?

Petroleum is not related to Natural gas.

I would rather work at my $100/hour job than at chopping wood for hours to
save $3/hour

I have no license, I wire and inspect other's wiring for a job and work for
a medium size electrical utility.

As a design engineer of transformers for 10 years I happen to know you are full
of shit.

I am a Protection & Control Tech by profession and have experience with control
systems

Try spelling "bus" correctly! Maybe your brain will start again. Probaby not,
you fucking loser.
## Referring to the correctly spelled word 'buss' as used in real electrical
terminology ##
## http://tinyurl.com/5ctml ##

X10 signals are transmitted just after the voltage waveform zero crossing.
This is in order to avoid conflicts with SCR and Triac peak waveform
switching spikes from load type devices such as lamp dimmers.
## control module misinformation ##

Besides when they on any line they will pull of the meter as a disconnect point.
## speaking of power line guys miles away removing YOUR electrical meter for
THEIR safety ##

My workplace has been throwing out huge digitizing pallettes (like 24 x 36" units)
## in alt.sewing.mach-embroider ##

The majority prefers top posting.

Not one of your suggesters listened to what the OP requested...LOL

Get your tear ducts flushed by a knowledgeable optometrist.

Not many materials have the huge exponential resistance/heat curve aluminum
does. Overload doesn't make it glow like copper...it flashes and explodes.

A bathroom fan motor would never push hot air down ten feet or cold up ten
feet.

Bathroom fans have a hard time pushing 55 cfm through a 3-4" pipe 20
horizontal feet. They are made to vent smells and humid air horizontally
only.

Why not spend the money on a contract with the grid company and get an
exclusive line to your house and never have brownouts.

Usenet rules dictate top posting for readability

Many cell modems are set up to filter bottom posts out.

Cell modems do not cut off anything.

What security flaws.
##referring to Outlook Express##

10 pounds per gallon Imperial. That gallon is totally unique to the
US....ooops..I think all gallons are unique to the US now.

The standard Imperial gallon the whole world used weighs 10 pounds exactly.

The copper isn't worth more than 5 cents per pound. It is classed a mixed
copper and nobody wants it.

Hey moron! The copper is considered "mixed" copper and is worth about $0.02
per pound, if he seperates it all.

Just don't ever lose weight. Toxins are stored in your fat cells.

Did you know, **NO***, I repeat ***NO*** death has ever been related to
PCBs?

Insulated square copper wires from a dry transformer are not 99% copper and
take a lot of work to remove the insulation.

I have tonnes of insulated copper wire if you want it. I think you could
almost have for the picking it up. How many bins can you take per year

50 lbs? We have it by the bin full. Mostly #6 to 650 MCM. I beleive you
would have to leave a bin and then pick it up full later to compete with the
current scrapper.

Can't this tranformer be used by somebody to generate a second 120V from a
single phase 120V inverter? It sounds pretty beefy.

BTW: once you knock the wedge out of the coil form the laminations will be
easier to get out. This keeps them from buzzing until the varnish and other
impregnations go into it.

All you guys have a bad Christmas or Jewish and didn't see Santa or something?

Run each signal twisted with a ground for noise. RD twisted with gnd as a
pair, TD twisted around ground as a pair etc... This means signal/logic
ground not power ground or case ground, if they are different. Do not
connect the other ends of the ground conductors.

Tar pitch in a flourescent ballast does ***NOT*** contain PCBs and probably
never did.

Religion is not genetic or even herodigious

I believe the warmest part of the lake is just below the ice. As the water
frezes it rises to the top and joins the other ice formations.

Gel cell won't cut it when it comes to putting out 100A or more. They cook in
one spot and the rest of the electrolyte doesn't circulate fast enough.

There is nothing standard about USanian measurements. They changed their
sizes to avoid trading with the rest of the world. This worked for a few
centuries but the rest of the world moved on to the metric system to avert
the confusion the US caused.

Ever put your ohmmeter (do I need to explain an ohmmeter also?) across a
capacitor? It measures infinity after charging to the supply voltage because the
electrolyte is an insulator.

Electrolytes are not conductors of electricity in a capacitor.

If the electrolyte conducted it would be a resistor.

I doubt they are 4 farads. More likely 4 microfarads uf.
## referring to 4000mfd caps ##

Sometimes it is an ego boost to have these so-called "professionals" come and
beg for information because they can't our toys do what the good guys can but I
would never hire them given a choice.

I have never had problems running RS232 at 19K2 through 14kV switchgear so far
but I use twisted pair and sheilded cable combos and observe allt he good
grounding techniques etc. The other engineers always want to ground both ends
but in an area with 10Kampere faults that isn't a good idea.

Try rereading what I posted and try a basic English comprehension course
before you make a complete fool out of yourself again.

Do you measure altitude in degrees? Many aeronautical people would disagree with
you.
## referring to solar azimuth/altitude thread ##

My house is filled with motion detectors. They don't all operate lights. They
mostly signal my house control computer and it decides what to do and when.

Enlighten please (like it really matters...LOL)

I will hand stitch my embroidery before I would pay that kind of money...LOL

A 50Hz transformer needs double the iron a 60Hz transformer needs for the same
VA capacity.

Does it test CTs with real current or just voltage?

It doesn't really matter where the secondary current comes from, secondary
exciting or primary current exciting, the voltage developed or excited across it
will be about the same.
## talking about an OPEN circuit CT transformer ##

High voltage spikes want to keep going at the end and this is where your
saturating core transformer core is located behind the fuse.

Moving a kill-a-watt unit around is like using it on somebody else's house and
telling the person's load.

oooops. A flourescent with a filament?
## not knowing how most fluorescents start up ##

You are a stupid basterd.

Ever considered anxiety medication? Chest pains for a man is a classic symptom.

When confronted with many websites stating the otherwise he won't address the
issue but repeats his crap again like a child stamping his feet.
## Oh, the Irony! ##

What are you doing up at this ungawdly hour? I just got finished embroidering
about 10 items, including a flight bag for golf clubs.
## in alt.sewing.mach-embroider ##

I just love women with front loading bobbins.
## in alt.sewing.mach-embroider ##

I doubt a 6 needle machine would be faster than a 1 needle machine unless you do
repetitive patterns.
## in alt.sewing.mach-embroider ##

I had many problems with this and damaged my machine a few times. It was the
needles. Find ones that have very little "hip" bump around the eye of the needle.
## in alt.sewing.mach-embroider ##

I have found doctors absolutely ignorant and totally obstinet on these kind of
issues.

I put my first child on Ritalin for a year or so when quite young. It beat going
to prison for beating him black and blue.

I made a big mistake and should have "drugged" all of my children the same.

Once again you are an ignorant asshole disguising your lack of confidence

I did the chem.cut medication stuff for a few years with my first child and then
found Naturopathic Doctors using homeopathy to get more lasting relief.

Homeopathics saved me thousands of dollars for operations I did not have on my
children

Accupunture worked for my 1 and two year old children for ailments after the
medical doctors could do nothing for.

Placebo is a completely natural cure for many ailments.

Polio Vaccine? They stopped giving that one long before HIV was invented.

You have no idea what you are talking about and either does anybody else here.

See if you can replace it with a thermal acting unit. They have a rachet on a
shaft that holds thew contacts closed.
## confusing motor overload with breaker ##

What are you doing in my group?

Milk is just plain poison for humans.

I am not a chemist but I know that cow's milk calcium molecules are a huge
irritant to human digestion and usually results in calcium deficiencies

See an accupunturist for the pain and circulation
See a chiropractor to keep the structure good.
See a naturopathic doctor for the chemical imbalance.
See a medical doctor for a some poison that will make her life shorter.

Even an honest Doctor will take yoy they arte totally ignorant of nutrition.

The medical doctors will play the time game and probably just let him die after
removing half his organs because they may be a problem.

Some things mankind should just not eat too much of and it isn't meat typically
and this may not be consistent for all people.

Do not listen to the stories of addiction. Yes, they are tough to stop but so is
insulin for a diabetic. I have stopped taking mine and it wasn't that bad but
after months of regressing I chose to return like the other half the population.

Make sure your wrists are well warmed up before putting sudden jerky movements
to them.

Make up your mind before you mouth off like the usual Internet piece of shit.
This is a rough group and if you had followed the usual recommendations you
would have known that and have nothing to say about it.
## in misc.kids.health, alt.support.breast-implant, misc.health.alternative ##

Bad practice to ground yourself when working on electronics. It increases the
chance of injury or death by electrical shock and also increases the chance of
static discharge to the circuit chips. Ground is a potential too.

Oink...Oink...just take it out. What could be simpler?
## in soc.support.fat-acceptance, alt.support.big-folks ##

No hyphen in the word multi-syllabic.

## Gymy Bob's endorsement of anal sex censored##
## sorry, I have my limits ##

A complete fucking idiot spurted out his piehole:
## in misc.health.alternative ##

I was born depressed and never realized until about 3 years ago. I am 52 and
went for medication because of anxiety.

The English can't stand each other, let alone other cultures.
If you don't believe me brother just ask the rest of my family that I
disowned.

I find most Americans likeable and they find me likeable after they open
their wallets far enough to make me that way.
How many american dollars will it take to make you suck their dicks?
## in alt.support.attn-deficit, misc.health.alternative ##

How much for a blow job?

Believe me, "America" is so far behind on internet usage over many South
American countries. They just don't happen to post in English and not many
of you could possibly understand other languages even exist.

WTF is CBT? Chekaslovakia Book Therapy?

Try your left hand. It feels like somebody else's hand sometimes.
## pdaxs.services.massage, misc.health.alternative, alt.backrubs,
alt.health.massage-therapy ##

OK, you're not a moron. You are above average for Nova Scotia.

Another tidbit for the brainless twit with the big mouth here

Pehaps magnesium supplementation would allow these buffoons to utilize some
of their already overloaded calcium intake.

This guy is a total buffoon and has no knowledge of any part of his own sentence.

Where should you shove it?

Fish oil is mainly responsible for your placebo also.
## in misc.health.alternative##

After disassembling Bill Gates' 6800 Basic back in the 70s I knew he was a dirty
software scoundrel.

The government makes more on the taxes than the tax rate when this is done.

Be blabest tofart.
## ???? in alt.comp.periphs.dcameras ##

Blood may be kept at a stable 7.4 pH but a piece of copper wire passes
electricity through it even though the number of electrons remains constant.
## in misc.health.alternative ##

I have had amazing effects from some homeopathic remedies and others did nothing.

These homeopathic know-it-alls drive me crazy with their 1880 knowledge.

Sorry, but testing has proven homeopathic remedies to be effective remedies.

I have taken a few homeopathic remedies that taste like crap. Funny how pure
water could do that.

Homeopathic remedies are very toxic substances and used because of their toxic
properties.

Standard homeopathic science.

Your ignorance of homeopathy does not mean it is useless.

Everybody always follows the screaming, left-wing, maniac, tooting we are all
going to die by doing another therapy.

I have had achilles tendonitus for the past 2-3 years now. I got rid of it
on one side by grinding out the bones spurs underneath with the side of a
screwdriver blade and lots of oil.

GET OFF THE WHEAT, CORN & OATS!!!

It doesn't matter how well it works if the doctor doesn't say so (with his two
years of college) then it just ain't so.

Heat pumps are 300% efficient when the weather is fine but the compressor
motors? hmmm about 60%.

You are obviously a moron and you keep repeating it here.
## referring to my corrections of his postings ##

 

[Gymn Bob]

always an asshole.

Hold still morpher while I **** some brains into ya' again.

<PLONK>

 

[daestrom]

PT Industries (1 800 44 ENDOT) sell 1/2"x400' coils of 125 psi (tested to
600 psi) NSF-certified HDPE pipe (0.752" OD and 0.622" ID, with a nominal
minimum bending radius of 20xOD = 15") for $67, list. Ferguson's price is
$48. I figure 800' in 3 vertical spirals in a 55-gallon drum with a liner
and a removable bolt-ring top would have 143 ft^2 of surface and hold 12.5
gallons, with an NTU of 6.8 and a burst efficacy of 87%. The layers could
use some separators to prevent nesting, eg some lengthwise slices of pipe.
This single-wall heat exchanger is not NSF-compliant as is, but endurance
testing and leak detection and safety devices could change that.

It has enough volume to do better over a day, with water usage in small
bursts, eg a 10 minute 1.25 gpm shower. How could we calculate that? I
tried hard to make this with 300' of 1" pipe, but it kinked too often
when two of us (looking like Laurel and Hardy tried to spiral it
carefully into a drum on a warm day...

Well, there ya go. There's a reason they recommend 20xOD for a bending
radius ;-)

But I noticed from your program, that you're still planning on only 11.75"
radius with this smaller stuff (vice 15").

All the holes would be in the drum lid. Cold water would enter the spirals
at the bottom via a dip tube and exit from the top. Greywater would enter
the bulk of the drum at the top via a 1.5" PVC dip tube with holes to let
it find its own thermal level and leave from the bottom via another tube,
with 1-2 psi in the drum to get it back up into a sewer pipe near the top
of a basement ceiling (The GFX requires lots of vertical drop.) We might
put a thermostat on the lid and an electric heating element through the
lid
to make a standalone water heater.

If I interpreted your program correctly, you'll have a central 'core' of
flooded water. That means a 12.5 gal 'slug' of water coming in on the
greywater side will displace the cooler water downward only about 10.2". So
the coil has to be right against the top of the drum and even so 24" of it
will be in 'stale' water. It might be better if you could plug the 'core'
with some material. That way 12.5 gallons of warm water would extend over
much of the tube spirals. Preferably something with low heat capacitance
and low conductivity. It might be possible to cut several strips of
foamboard and stack them lengthwise together to make a sort of 'plug'. Of
course it will try to 'float' up so it would need a weight (5.6ft^3 or about
350lbm) to keep it in place (unless you think the lid would be strong
enough, but I doubt it).

With 34.5" tall coils, you don't have any space between successive layers
except for the interstitial space around the tubing. If you have some
tubing left over, maybe you could make spacers with short sections. Some
smaller tubing cut to short lengths to lay on the 'valley' formed by the
outer and middle tube and the other 'valley' formed by the middle and inner
tube. Doesn't have to be as large as the main tubing, just something to
keep successive layers of tubing from touching each other and provide a
space for the greywater to flow.

Don't forget to have an air vent on the greywater drain going into the unit.
Something like just a tee with a short riser to start with. Unless its
connected to some other drains, there wouldn't be any real sewer gas
problem, but you want any air entrained with the shower drain water to vent
out *before* entering the drum.

Of course it will need a wrapper of insulation to try and hold in the heat
from the last shower of the day. Even so, I don't think you'll get the
'burst' mode effectiveness of 99%. You may be able to still manage to
collect a fair amount of the greywater's heat though.

Keep us posted.

daestrom

 

[Noon-Air]

Dude...is there any special reason you are cross-posting this to 6 different
groups???

 

[Gìmmìe Bob]

Cross posting is highly recommended by Usenet as memory space saver. You
been hiding?

 

[daestrom]

Dude...is there any special reason you are cross-posting this to 6
different groups???

Perhaps the same reason you replied to 6 different groups? So the
originator posting on one of those groups would be sure to read it. At
least they are somewhat relavent to the groups involved (although more to
some than others, to be sure).

daestrom

 

[[email protected]]

Well, there ya go. There's a reason they recommend 20xOD for a bending
radius ;-)

The 1" pipe _almost_ worked. The ENDOT ap engineer thought it would.
I tried heating, an inner rolling form, etc. Someone could probably
build a simple machine to do this.

But I noticed from your program, that you're still planning on only 11.75"
radius with this smaller stuff (vice 15").

The 1/2" pipe comes in a 25" ID roll... I should try this before buying 800'.

20 DOP=.752'pipe od (inches)...
50 RLOOP=23.5/2'loop radius (inches)... [11.75"]
100 RLOOP=RLOOP-DOP'loop radius (inches)... [11.00"]
150 RLOOP=RLOOP-DOP'loop radius (inches)... [10.25"]
190 PRINT 3,RLOOP/DOP,NTURNS,LLAYER

3 13.625 45.87767 246.1242

If I interpreted your program correctly, you'll have a central 'core' of
flooded water. That means a 12.5 gal 'slug' of water coming in on the
greywater side will displace the cooler water downward only about 10.2". So
the coil has to be right against the top of the drum and even so 24" of it
will be in 'stale' water.

That might be OK, given the input dip tube with holes. What size and spacing?
The greywater temp may vary, with a cold burst once in a while. More volume
might mean we can get closer to that 99% continuous effectiveness.

It might be better if you could plug the 'core' with some material. That
way 12.5 gallons of warm water would extend over much of the tube spirals.

Or 12.5 gallons of cold water...

...It might be possible to cut several strips of foamboard and stack them
lengthwise together to make a sort of 'plug'. Of course it will try to
'float' up so it would need a weight (5.6ft^3 or about 350lbm) to keep it
in place (unless you think the lid would be strong enough, but I doubt it).

With a 5' rise to a sewer pipe near the ceiling, the lid would already have
5x0.433x144xPi = 979 pounds pushing it up. The drum might be on a 4' hollow
block platform... 12-18 blocks... that would also help avoid rusting.

With 34.5" tall coils, you don't have any space between successive layers
except for the interstitial space around the tubing. If you have some
tubing left over, maybe you could make spacers with short sections. Some
smaller tubing cut to short lengths to lay on the 'valley' formed by the
outer and middle tube and the other 'valley' formed by the middle and inner
tube. Doesn't have to be as large as the main tubing, just something to
keep successive layers of tubing from touching each other and provide a
space for the greywater to flow.

That sounds like a lot of work. How about some thin vertical spacers,
maybe 24 of them, 8 for each layer, 34.5" x 1/2" x 1/8", and another
24 4" x 1/2" x 1/8" radial horizontal stickers? Someone might sell
plastic moldings in quantity.

Don't forget to have an air vent on the greywater drain going into the unit.
Something like just a tee with a short riser to start with. Unless its
connected to some other drains, there wouldn't be any real sewer gas
problem, but you want any air entrained with the shower drain water to vent
out *before* entering the drum.

We might collect shower and sink drains after their traps, using corrugated
sump pump hose for greywater I/O, with a 1' rise out of the drum to the sewer
drain pipe, with the output hose sealed fairly well into the pipe, but not
well enough to syphon all the water out of the drum. A friend tried something
like this with a 275 gal oil tank that wasn't airtight and didn't stay full,
so it pumped gas into the house. He said the odor was very impressive.

Of course it will need a wrapper of insulation to try and hold in the heat
from the last shower of the day.

A 4'x8' piece of foil-faced foamboard kerfed into an octagon with 3.5"
fiberglass insulation inside and over the top.

Even so, I don't think you'll get the 'burst' mode effectiveness of 99%.

Still wondering how to estimate this. An average home might need 50K Btu/day
of water heating. Drop this 95% to 2500 Btu/day (like a 30 watt bulb running
24 hours per day), and we might forget solar water heating entirely.

Keep us posted.

OK. Gary and I may do this with instrumention. We might all try this.
Martha Stewart has lots of indoor time on her hands...

BTW, this crossposting is relevant to each group. Some say "crossposting
is bad," but it's good netiquette, compared to identical individual posts,
which waste more electronic and human bandwidth.

20 DOP=.752'pipe od (inches)
30 DIP=.622'pipe id (inches)
40 NTURNS=34.5/DOP'number of turns in layer
50 RLOOP=23.5/2'loop radius (inches)...
100 RLOOP=RLOOP-DOP'loop radius (inches)...
150 RLOOP=RLOOP-DOP'loop radius (inches)...
190 PRINT 3,RLOOP/DOP,NTURNS,LLAYER
200 AP=AP+L*PI*(DOP+DIP)/2/12'pipe area (ft^2)
210 VP=VP+L*PI*(DIP/2/12)^2*7.48'pipe volume (gallons)
220 FLOW=1.25'gpm
230 LL=L/3'average layer pipe length (feet)
240 FL=FLOW/3'average flow per layer (gpm)
250 PL=.0004227*LL*FL^1.852*DIP^-4.871'Hazen-Williams pressure loss (psi)
260 PRINT L,AP,VP,PL
270 C=60*FLOW*8.33'burst heat capacity rate (Btu/h-F)
280 NTU=30*AP/C'burst NTU for counterflow heat exchanger
290 E=NTU/(NTU+1)'burst heat exchanger effectiveness
300 TCI=55'fresh water inlet temp (F)
310 TSH=110'shower head outlet temp (F)
320 THI=105'greywater inlet (shower drain) temp (F)
330 THO=TCI+E*(THI-TCI)'burst fresh water outlet temp (F)
340 ESAVINGS=100*(1-(TSH-THO)/(TSH-TCI))'burst % savings
350 VHW=120'daily hot water consumption (gallons)
360 CKWH=.1'$/kWh
370 DSAVINGS=365*ESAVINGS/100*VHW*8.33*(TSH-TCI)/3412*CKWH'$/year savings
380 PRINT NTU,E,THO,ESAVINGS,DSAVINGS
390 C=VHW*8.33/24'continuous heat capacity rate (Btu/h-F)
400 NTU=30*AP/C'continuous NTU for counterflow heat exchanger
410 E=NTU/(NTU+1)'continuous heat exchanger effectiveness
420 THO=TCI+E*(THI-TCI)'continuous fresh water outlet temp (F)
430 ESAVINGS=100*(1-(TSH-THO)/(TSH-TCI))'continuous % savings
440 DSAVINGS=365*ESAVINGS/100*VHW*8.33*(TSH-TCI)/3412*CKWH'$/year savings
450 PRINT NTU,E,THO,ESAVINGS,DSAVINGS

1 15.625 45.87767 282.2525
2 14.625 45.87767 264.1884
3 13.625 45.87767 246.1242

792.5651 142.5478 12.50964 .2229677

6.84503 .8725308 98.62654 79.32098 466.5099
102.6754 .9903546 104.5177 90.03223 529.5059

Nick

 

[[email protected]]

The 1/2" pipe comes in a 25" ID roll... I should try this before buying 800'.

I bent a loop of Silver Line 1/2" 100 psi SIDR 15 NSF pipe into
a 12" OD loop with no kinking. Lowes sells this for $9.58/100',
although it's being replaced with 125 psi SIDR 11.5 pipe. The ap
engineer says bending to less than 9X OD may affect longevity...

Nick

 

[daestrom]

Well, there ya go. There's a reason they recommend 20xOD for a bending
radius ;-)

The 1" pipe _almost_ worked. The ENDOT ap engineer thought it would.
I tried heating, an inner rolling form, etc. Someone could probably
build a simple machine to do this.

But I noticed from your program, that you're still planning on only 11.75"
radius with this smaller stuff (vice 15").

The 1/2" pipe comes in a 25" ID roll... I should try this before buying
800'.

20 DOP=.752'pipe od (inches)...
50 RLOOP=23.5/2'loop radius (inches)... [11.75"]
100 RLOOP=RLOOP-DOP'loop radius (inches)... [11.00"]
150 RLOOP=RLOOP-DOP'loop radius (inches)... [10.25"]
190 PRINT 3,RLOOP/DOP,NTURNS,LLAYER

3 13.625 45.87767 246.1242

If I interpreted your program correctly, you'll have a central 'core' of
flooded water. That means a 12.5 gal 'slug' of water coming in on the
greywater side will displace the cooler water downward only about 10.2".
So
the coil has to be right against the top of the drum and even so 24" of it
will be in 'stale' water.

That might be OK, given the input dip tube with holes. What size and
spacing?
The greywater temp may vary, with a cold burst once in a while. More
volume
might mean we can get closer to that 99% continuous effectiveness.

It might be better if you could plug the 'core' with some material. That
way 12.5 gallons of warm water would extend over much of the tube spirals.

Or 12.5 gallons of cold water...

...It might be possible to cut several strips of foamboard and stack them
lengthwise together to make a sort of 'plug'. Of course it will try to
'float' up so it would need a weight (5.6ft^3 or about 350lbm) to keep it
in place (unless you think the lid would be strong enough, but I doubt
it).

With a 5' rise to a sewer pipe near the ceiling, the lid would already
have
5x0.433x144xPi = 979 pounds pushing it up. The drum might be on a 4'
hollow
block platform... 12-18 blocks... that would also help avoid rusting.

With 34.5" tall coils, you don't have any space between successive layers
except for the interstitial space around the tubing. If you have some
tubing left over, maybe you could make spacers with short sections. Some
smaller tubing cut to short lengths to lay on the 'valley' formed by the
outer and middle tube and the other 'valley' formed by the middle and
inner
tube. Doesn't have to be as large as the main tubing, just something to
keep successive layers of tubing from touching each other and provide a
space for the greywater to flow.

That sounds like a lot of work. How about some thin vertical spacers,
maybe 24 of them, 8 for each layer, 34.5" x 1/2" x 1/8", and another
24 4" x 1/2" x 1/8" radial horizontal stickers? Someone might sell
plastic moldings in quantity.

Well, this depends. If you go with my idea of 'plugging' the central core,
you want to have something that will allow the greywater to flow around the
spirals. Flat spacers would act like periodic dams to the greywater flowing
down around the spiral. That's why I was thinking of some small hollow
tubing oriented parallel to the fresh-water tubing. It would maintain a gap
and allow greywater to flow through.

But if you don't plug the central core, it seems a lot of the greywater will
just stay in the central region and not warm the tubing very well. As more
warm greywater enters, it pushes down on the water in the central core and
you end up with warm water leaving the drain without much energy recovery.
Some of the water surrounding the tubing will be cooled and find it's way
down to the drain, but so would a lot of central core water.

Unless the flow is slow enough and intermittent enough that the cold water
surrounding the tubing can stratify with the central core water and actually
'fall' to the bottom of the drum in time. Really rather hard to say without
the experiment.

We might collect shower and sink drains after their traps, using
corrugated
sump pump hose for greywater I/O, with a 1' rise out of the drum to the
sewer
drain pipe, with the output hose sealed fairly well into the pipe, but not
well enough to syphon all the water out of the drum.

Well I was already assuming that it would be greywater from *after* all the
'P' or 'S' traps. But the barrel will act like a second trap in line with
it. So when you shut off the shower, the standing column of water from the
shower's trap to the barrel will tend to siphon water out of the shower's
trap. And when you start a new shower, the length of pipe from its trap to
barrel will be full of air and then the shower water will try to 'push' it
into the barrel (where it can never get out). To avoid all this, a vent
between the shower/sink traps and the barrel. Simple tee with the vent line
sloping constantly upwards. Would have to terminate at a point higher than
the barrel's outlet to the regular sewer. This wouldn't vent the sewer line
(the water in the drum would prevent that), how bad it smells would depend
on how bad the 'grey' water was, and/or how much 'debris' found its way into
the barrel to decay.

Modern plumbing requires a vent *downstream* of the traps of sinks and
showers so the drain line doesn't siphon air through the traps when you shut
off the water. You can tell sinks that don't have venting on the drain line
because when you fill it with water and then let the water out, it won't
drain well and as the last water leaves the sink, you can hear it gurgling
and sucking air through the trap for some time.

Still wondering how to estimate this. An average home might need 50K
Btu/day
of water heating. Drop this 95% to 2500 Btu/day (like a 30 watt bulb
running
24 hours per day), and we might forget solar water heating entirely.

Well, that's *if* you can get 95% (and that's a big 'if'). 50K is something
like 140 gal per person in a 5 person family per day (the dead of winter
with 45F inlet). That seems pretty high. Easier to just install low-flow
showerhead ;-) I've threatened my son (the 'water buffalo') with a timer
valve on the shower line that would shut off after 25 minutes ;-) Just the
threat has helped a lot.

daestrom

 

[Gìmmìe Bob]

All this gobble-dee-gook and the net result is greywater that will be cold
at the drain entrance because we have split the temperature with cold water
coming in. There wil not be any warm water result but possibly a compromise
in a perfect world. I doubt the 1.5 cents saved would be worth the energy to
create the system. Should pay for itself in what....... 400 years?

...800' in 3 vertical spirals in a 55-gallon drum with a liner and
a removable bolt-ring top would have 143 ft^2 of surface and hold 12.5
gallons, with an NTU of 6.8 and a burst efficacy of 87%. The layers
could
use some separators to prevent nesting...

It has enough volume to do better over a day, with water usage in small
bursts, eg a 10 minute 1.25 gpm shower. How could we calculate that? I
tried hard to make this with 300' of 1" pipe, but it kinked too often
when two of us (looking like Laurel and Hardy tried to spiral it
carefully into a drum on a warm day...

Well, there ya go. There's a reason they recommend 20xOD for a bending
radius ;-)

The 1" pipe _almost_ worked. The ENDOT ap engineer thought it would.
I tried heating, an inner rolling form, etc. Someone could probably
build a simple machine to do this.

But I noticed from your program, that you're still planning on only 11.75"
radius with this smaller stuff (vice 15").

The 1/2" pipe comes in a 25" ID roll... I should try this before buying
800'.

20 DOP=.752'pipe od (inches)...
50 RLOOP=23.5/2'loop radius (inches)... [11.75"]
100 RLOOP=RLOOP-DOP'loop radius (inches)... [11.00"]
150 RLOOP=RLOOP-DOP'loop radius (inches)... [10.25"]
190 PRINT 3,RLOOP/DOP,NTURNS,LLAYER

3 13.625 45.87767 246.1242

All the holes would be in the drum lid. Cold water would enter the
spirals
at the bottom via a dip tube and exit from the top. Greywater would
enter
the bulk of the drum at the top via a 1.5" PVC dip tube with holes to
let
it find its own thermal level...

If I interpreted your program correctly, you'll have a central 'core' of
flooded water. That means a 12.5 gal 'slug' of water coming in on the
greywater side will displace the cooler water downward only about 10.2".
So
the coil has to be right against the top of the drum and even so 24" of it
will be in 'stale' water.

That might be OK, given the input dip tube with holes. What size and
spacing?
The greywater temp may vary, with a cold burst once in a while. More
volume
might mean we can get closer to that 99% continuous effectiveness.

It might be better if you could plug the 'core' with some material. That
way 12.5 gallons of warm water would extend over much of the tube

spirals.

Or 12.5 gallons of cold water...

...It might be possible to cut several strips of foamboard and stack them
lengthwise together to make a sort of 'plug'. Of course it will try to
'float' up so it would need a weight (5.6ft^3 or about 350lbm) to keep it
in place (unless you think the lid would be strong enough, but I doubt
it).

With a 5' rise to a sewer pipe near the ceiling, the lid would already
have
5x0.433x144xPi = 979 pounds pushing it up. The drum might be on a 4'
hollow
block platform... 12-18 blocks... that would also help avoid rusting.

With 34.5" tall coils, you don't have any space between successive layers
except for the interstitial space around the tubing. If you have some
tubing left over, maybe you could make spacers with short sections. Some
smaller tubing cut to short lengths to lay on the 'valley' formed by the
outer and middle tube and the other 'valley' formed by the middle and
inner
tube. Doesn't have to be as large as the main tubing, just something to
keep successive layers of tubing from touching each other and provide a
space for the greywater to flow.

That sounds like a lot of work. How about some thin vertical spacers,
maybe 24 of them, 8 for each layer, 34.5" x 1/2" x 1/8", and another
24 4" x 1/2" x 1/8" radial horizontal stickers? Someone might sell
plastic moldings in quantity.

Well, this depends. If you go with my idea of 'plugging' the central core,
you want to have something that will allow the greywater to flow around the
spirals. Flat spacers would act like periodic dams to the greywater flowing
down around the spiral. That's why I was thinking of some small hollow
tubing oriented parallel to the fresh-water tubing. It would maintain a gap
and allow greywater to flow through.

But if you don't plug the central core, it seems a lot of the greywater will
just stay in the central region and not warm the tubing very well. As more
warm greywater enters, it pushes down on the water in the central core and
you end up with warm water leaving the drain without much energy recovery.
Some of the water surrounding the tubing will be cooled and find it's way
down to the drain, but so would a lot of central core water.

Unless the flow is slow enough and intermittent enough that the cold water
surrounding the tubing can stratify with the central core water and actually
'fall' to the bottom of the drum in time. Really rather hard to say without
the experiment.

We might collect shower and sink drains after their traps, using
corrugated
sump pump hose for greywater I/O, with a 1' rise out of the drum to the
sewer
drain pipe, with the output hose sealed fairly well into the pipe, but not
well enough to syphon all the water out of the drum.

Well I was already assuming that it would be greywater from *after* all the
'P' or 'S' traps. But the barrel will act like a second trap in line with
it. So when you shut off the shower, the standing column of water from the
shower's trap to the barrel will tend to siphon water out of the shower's
trap. And when you start a new shower, the length of pipe from its trap to
barrel will be full of air and then the shower water will try to 'push' it
into the barrel (where it can never get out). To avoid all this, a vent
between the shower/sink traps and the barrel. Simple tee with the vent line
sloping constantly upwards. Would have to terminate at a point higher than
the barrel's outlet to the regular sewer. This wouldn't vent the sewer line
(the water in the drum would prevent that), how bad it smells would depend
on how bad the 'grey' water was, and/or how much 'debris' found its way into
the barrel to decay.

Modern plumbing requires a vent *downstream* of the traps of sinks and
showers so the drain line doesn't siphon air through the traps when you shut
off the water. You can tell sinks that don't have venting on the drain line
because when you fill it with water and then let the water out, it won't
drain well and as the last water leaves the sink, you can hear it gurgling
and sucking air through the trap for some time.

Still wondering how to estimate this. An average home might need 50K
Btu/day
of water heating. Drop this 95% to 2500 Btu/day (like a 30 watt bulb
running
24 hours per day), and we might forget solar water heating entirely.

Well, that's *if* you can get 95% (and that's a big 'if'). 50K is something
like 140 gal per person in a 5 person family per day (the dead of winter
with 45F inlet). That seems pretty high. Easier to just install low-flow
showerhead ;-) I've threatened my son (the 'water buffalo') with a timer
valve on the shower line that would shut off after 25 minutes ;-) Just the
threat has helped a lot.

daestrom

 

[daestrom]

All this gobble-dee-gook and the net result is greywater that will be cold
at the drain entrance because we have split the temperature with cold
water
coming in. There wil not be any warm water result but possibly a
compromise
in a perfect world. I doubt the 1.5 cents saved would be worth the energy
to
create the system. Should pay for itself in what....... 400 years?

What are you talking about?? The greywater drain from a shower is over 100
F. It doesn't 'mix' with anything before it reaches the heat exchanger. If
things work as designed, *after* the heat exchanger the greywater will be
cold because it will have given up its heat to the incoming freshwater.

Taking a 110F shower for 20 minutes at 1.5 gpm requires 15kBTU to heat
incoming 50F water up to 110F. In 'normal' installations this 15kBTU is
wasted down the drain (literally). Recovering just *some* of this heat can
be a real savings. A family of five, each taking four showers a week would
be 300kBTU/week. If you use NG to heat water (one of the cheapest
conventional fuels used) that can be $135 / year. If you use electric at
$0.10/kWh, that 300kBTU/week runs you about $457/year

If a heat exchanger can pre-heat the incoming water (with the energy that
formerly was sent down the drain) by 30F, then it would recover $68 /year
from NG heated water, ($228/yr electric). Build a heat exchanger for < $300
and you can see a reasonably good pay back. I'm skeptical that Nick's
design will reach the 99% that his calculations predict, but even at 50%
(just 30F rise) it can be a good investment.

Apparently you have no idea how much is spent on domestic water heating.

daestrom

 

[[email protected]]

...Flat spacers would act like periodic dams to the greywater flowing
down around the spiral.

These radial stickers would be perpendicular to the pipe.

But if you don't plug the central core, it seems a lot of the greywater will
just stay in the central region and not warm the tubing very well.

Recall the holey dip tube. Stratified greywater storage might work better
with more volume and no central core for batch uses like bathtubs...

As more warm greywater enters, it pushes down on the water in the central
core and you end up with warm water leaving the drain without much energy
recovery. Some of the water surrounding the tubing will be cooled and find
it's way down to the drain, but so would a lot of central core water.

Warmer incoming greywater should float on vs "push down" cooler greywater
that's already given up heat to fresh water. Fig. 8.4.2 on page 389 of Duffie
and Beckman's Solar Engineering... 2nd edition is a nice photo of "Dyed water
entering a stratified tank through a low-velocity manifold." It flows down
a holey dip tube and then horizontally out into clear tank water from some of
the middle holes of the dip tube, creating a cloudy black pancake that thins
near the edges. No incoming black water flows out of the holes above and below
the pancake.

Unless the flow is slow enough and intermittent enough that the cold water
surrounding the tubing can stratify with the central core water and actually
'fall' to the bottom of the drum in time.

That's the idea. What's a good hole size and spacing for a 1.5"x34.5" tube?
The D&B fig looks like a 1" tube with 4 1/8" holes on 1/4" vertical centers.

We do? Well, that might not smell too awful. Oh wait. That can vent to the
sewer pipe (and in turn to its vent), so it needn't smell up the house

On second thought, that won't happen if the sewer pipe is vented.

...the barrel will act like a second trap in line with it. So when you shut
off the shower, the standing column of water from the shower's trap to the
barrel will tend to siphon water out of the shower's trap...

Not if the downstream side of the shower trap is vented.

And when you start a new shower, the length of pipe from its trap to
barrel will be full of air and then the shower water will try to 'push' it
into the barrel (where it can never get out). To avoid all this, a vent
between the shower/sink traps and the barrel...

Maybe something like this, viewed in a fixed font:

^
sewer | shower
vent | drain
------- |
| sewer |<-----*----------- ------
| pipe | | | --------
------- ^ \|/ shower
| | trap
---------
| | h |
drum | | h | h is the holey dip tube.
| | h |
| | h | The * section would vent everything downstream
| | h | from the shower trap to outdoors and provide
| | h | an overflow path if the drum clogs up...
---------

I don't either, but 87% isn't shabby.

...50K is something like 140 gal per person in a 5 person family per day
(the dead of winter with 45F inlet). That seems pretty high...

....140x5x8.33(110-45) = 379K Btu/day.

Nick

 

[Gìmmìe Bob]

Where did youi see this statement? You have to stick with things said.
"It doesn't 'mix' with anything before it reaches the heat exchanger"

The greywater will not be the same temp as the showerhead. After heating the
pipes, shower walls, your body, evaporation etc. my guess would be about 90
F. But let's assume maybe 100F.

Streetwater, depending on the season (here) may come in at about 55F.

If we have a perfect heat exchange (we never will). The liquid temperatures
will exit the system at the same temperature. If the volumes are exactly the
same (they shouldn't be) both liquids would be half the sums or 77.5F

Now raising the water (before the heater I assume) 22.5F during a shower
will save aprox 22.5/(140-55) of the used shower water heating or about
26.5% of the water used for showering.

I figure I use half my water (probably much less) in showers then I would
save aprox

1/2 x 26.5% x $135 (your cost figure) = $17.88 per year. This is avsuming no
first rates or fixed monthly fees (this doesn't usually happen) that won't
prorate into the cost anyway.

This is more likely (after all the gimmie factors) to be in the order of
about $5 but we haven't included any maintenance of the system or
inefficiencies due to shampoo and soap build up. The costs of disassembling
and/or replacing the whole system because the graywater is full of
congealing soap sludge (plumbing specs slope for a reason), or the
amortization of the money that could be making interest or investment income
some place else.

I suspest the system will never pay for itself. The 400 years may have been
hopeful.

But it would be fun to play with. A few dollars in 1-wire thermal probes and
some cable? Plumb -away!

 

[[email protected]]

If we have a perfect heat exchange (we never will). The liquid temperatures
will exit the system at the same temperature. If the volumes are exactly the
same (they shouldn't be) both liquids would be half the sums or 77.5F

I'm afraid you are quite ignorant, with little to add here. In such
a position, many people would choose to learn more, or add less

Nick

 

[Gìmmìe Bob]

LOL

I was thinking the same thing about you. It is very hard to learn from your
insults though. They are on par with your math.

100 I=10
200 X=12
300 X = I * X
400 Print I, X , X*2
10 120 240

Let us know when your perfect heat exchanger works. Some may be still alive.

 

[daestrom]

Where did youi see this statement? You have to stick with things said.
"It doesn't 'mix' with anything before it reaches the heat exchanger"

The greywater will not be the same temp as the showerhead. After heating
the
pipes, shower walls, your body, evaporation etc. my guess would be about
90
F. But let's assume maybe 100F.

Streetwater, depending on the season (here) may come in at about 55F.

If we have a perfect heat exchange (we never will). The liquid
temperatures
will exit the system at the same temperature. If the volumes are exactly
the
same (they shouldn't be) both liquids would be half the sums or 77.5F

BZZT. You are assuming a type of heat exchanger called a 'parallel flow'
heat exchanger. In such a system, it is true the outlet of both water flows
would be equal. And for equal flows in both sides, the temperature in an
perfect heat exchanger would be the mid point between the two.

But these are 'counter flow' heat exchangers. The hot water enters at one
end, and the cold water enters the tubing at the opposite end. In a perfect
one of these, the 'cold' water would exit at the same temperature as what
the 'hot' water enters at (100F). And the 'hot' water leaves at the same
temperature as the 'cold' water at the other end.

At 80% effectiveness, you would have....

Hot (100F) -> ------------------------- -> Drain (64F)
Household (91F) <--------------------- <- Supply (55F)

Now raising the water (before the heater I assume) 22.5F during a shower
will save aprox 22.5/(140-55) of the used shower water heating or about
26.5% of the water used for showering.

If you are silly enough to only hook up the heat exchanger output to *just*
the hot water inlet, then you get what you get. Hooking it up to supply the
heater *and* the 'cold' line to the shower is much more effective. With the
'cold' line to the shower also pre-warmed, you use less hot water to achieve
your 105F shower. More savings.

If the shower is 105F and inlet is 55F, and you warm the incoming water to
91F, then the savings are (91-55)/(105-55) = 72%

I figure I use half my water (probably much less) in showers then I would
save aprox

1/2 x 26.5% x $135 (your cost figure) = $17.88 per year. This is avsuming
no
first rates or fixed monthly fees (this doesn't usually happen) that won't
prorate into the cost anyway.

No, the first rates and fixed fees are not in the $135 figure. The figures
are *just* the marginal cost per btu used in heating. But your efficiency
figures are way too low for a counter-flow heat exchanger. Also the $135
figure is *just* shower water, not all water. So you are wrong to apply the
'1/2' figure there as well.

This is more likely (after all the gimmie factors) to be in the order of
about $5 but we haven't included any maintenance of the system or
inefficiencies due to shampoo and soap build up. The costs of
disassembling
and/or replacing the whole system because the graywater is full of
congealing soap sludge (plumbing specs slope for a reason),

Maintenance is zero for mine. Shampoo and soap do *not* build up in mine.
Been using it for three years with no problems, no maintenance. The
velocity of the water film is so high it keeps the interior scoured clean.
We won't know if Nick's design suffers from fouling until he builds it ;-)

See questions S and T. Study the rest of the web site and the DOE report on
GFX heat exchangers.

http://gfxtechnology.com/faq.html


or the

amortization of the money that could be making interest or investment
income
some place else.

I suspest the system will never pay for itself. The 400 years may have
been
hopeful.

Your analysis is poor. You don't understand the basic concepts of
counter-flow heat exchangers. You incorrectly assumed my example's annual
costs of $135 included fixed costs and non-shower usage despite my clear
explanation of how it was derived. You don't understand the technology of
vertical gfx systems.

My experience with mine has already paid for over 3/4 of its cost in just 3
years. (original cost for my GFX heat exchanger w/shipping was $269)

But it would be fun to play with. A few dollars in 1-wire thermal probes
and
some cable? Plumb -away!

Been there, done that. When I used the shower last night, here are the
numbers. I've been recording temperatures and flows for some time now using
1-wire sensors.

HX inlet temperature on freshwater side 41.3 F
HX outlet temperature on freshwater side 69.8 F
Flow 1.48 gpm
Length of time 22 minutes

Energy recovered (69.8-41.3) * 1.48*22*8.33 = 7730 BTU (this is an overall
effectiveness of only 48%). Since I have a NG heater (~80% efficient) and I
pay $0.70/therm (marginal price, not total), this one shower saved me
$0.067. With a family of five, averaging four showers a week for each of
them, that's $70/year. If I used an electric heater, that one shower would
have saved me $0.22 and would add up to $235/year (and my costs would have
been paid back in less than 2 years).

daestrom

 

[Gìmmìe Bob]

Interesting stuff. Thanx for the information, especially the heat exchange
method. I have never heard of this technique before (never looked
either...LOL)

Some points noted:
-Your heat exchanger measurements does not live up the theory (call in
ineffieciencies maybe due to size etc.)
- Your NG bill must be much higher than mine I would have to do some
research but I doubt my hot water bill was much over $135 Canuck for the
year including the rates etc. The rental was more though...LOL Then again I
cannot separate my heating from the HW very well as I have a gas stove etc.
I may be basing ideas on old prices. Must rethink that one.
- Last thing I heard , he was talking a barrel at the end of the greywater
drain as a heat exhanger. I had suggested the "in-pipe" method and thought
he forgot it due to mechanical logistics. (maybe I haven't followed that
closely) He was also feeding it into his hot water heater as a preheater.
This method seems much more logical in the physics dept.
- I like the "water has to prewarm the pipes" idea. I stated erlier that I
wait about 1.5-2 minutes for my hot shower each morning.
- I take a 10-12 minute shower each day, washing my hair and shaving too. If
you use a blade, get a mirror in the shower and you will never shave in the
sink again. Does a much cleaner/nicer job on your face.

Have a great one!

 

[daestrom]

These radial stickers would be perpendicular to the pipe.

Exactly. So they would block water from spiraling down the outside of the
tubes. The water would have to travel radially in towards the center and
then it is no longer in contact with the tubing. Moving inward would be
counter to the 'pancake' of warm water in the middle. But perhaps it can
just move inward enough to 'fall' off the spiral down until it reaches water
of its own temperature.

Recall the holey dip tube. Stratified greywater storage might work better
with more volume and no central core for batch uses like bathtubs...


Warmer incoming greywater should float on vs "push down" cooler greywater
that's already given up heat to fresh water.

Same thing. The 'cold' water is underneath the warm water. But most of the
water is in the center of the circle around which the tubing is arranged.
(looking down from above, most of the water is inside the circle formed by
the tube spirals).

Fig. 8.4.2 on page 389 of Duffie
and Beckman's Solar Engineering... 2nd edition is a nice photo of "Dyed
water
entering a stratified tank through a low-velocity manifold." It flows down
a holey dip tube and then horizontally out into clear tank water from some
of
the middle holes of the dip tube, creating a cloudy black pancake that
thins
near the edges. No incoming black water flows out of the holes above and
below
the pancake.

Interesting. But this *still* puts most of the warm water in a thin
'pancake' and only the outer rim of the 'pancake' is in contact with the
tubing. Once that rim of the pancake cools, it must somehow 'get out of the
way' so the rest of the 'pancake' can spread outward and thinner to come in
contact with the tubing.

If a large part of the 'core' is excluded/displaced, then you get a sort of
doughnut shape around the central 'plug'. This warm doughnut would be
thicker and contact more tubing. And that's a good thing.

This 'plug' doesn't have to be a tight fit with the tubing. In fact it
would probably help if there was a gap for the doughnut to form. But a
'thicker doughnut' would warm more of the tubing in a shorter time.

We do? Well, that might not smell too awful. Oh wait. That can vent to the
sewer pipe (and in turn to its vent), so it needn't smell up the house

I didn't intend that you vent 'inboard' to the basement ;-) Just that it
needs to be 'vented'. Out the basement window, back to the sewer stack
would be fine.

On second thought, that won't happen if the sewer pipe is vented.


Not if the downstream side of the shower trap is vented.

Exactly. That is *why* you want a vent between shower and drum.

Maybe something like this, viewed in a fixed font:

^
sewer | shower
vent | drain
------- |
| sewer |<-----*----------- ------
| pipe | | | --------
------- ^ \|/ shower
| | trap
---------
| | h |
drum | | h | h is the holey dip tube.
| | h |
| | h | The * section would vent everything downstream
| | h | from the shower trap to outdoors and provide
| | h | an overflow path if the drum clogs up...

Yes, I think you have the idea. Just some 'alternate' path for the air in
the pipe between the two traps (the shower's and the drum).

I don't either, but 87% isn't shabby.


...140x5x8.33(110-45) = 379K Btu/day.

You're right of course. Missed a density factor there...

daestrom