Goto www.gfxtechnology.com/GFX-STAR.html and click on Application Notes
and click on the link to Retrofit of an existing Solar Hot Water Heater.
You sir, need to READ first, before you make accusations that you cannot
back up with facts.
In there he describes a patent pending application of GFX Star in an
industrial process control application.
The models of what happens to the efficiency of his product with
changing potable water flows thru the equipment are there for all to see.
Your attitude makes it DIFFICULT to hold a meaningful conversation with
you. I'm not the first to say this.
My use of one of these, whether it is yours, a GFX, or a Power Pipe will
closely follow the GFX Star guidelines. That is, a small, inexpensive
pump controlled by a differential temperature controller will move water
thru the coils ALWAYS in excess of water draw from the hot water tank.
Very nearly 100% of my hotwater use WILL be going thru a heat exchanger,
and with 4x coil flow to drain flow in almost all of my cases,
efficiency of a 60inch S4 rises to over 74%.
I will NOT hang a 7 foot diameter coil of black PE tubing on the wall of
my utility room, one that needs annual disassembly to hose down/ brush
down the interior of the gray water containment pipe. Neither GFX nor
Power-Pipe need such cleaning as they are NON clogging, even with BLACK
water. Things may back up upstream or downstream of them, but not
OK, its not the 90+% that your model shows, but efficiency and cost are
NOT the only criteria as we have already discussed.
Actually since he has a Patent application pending, if you attempt to
offer a competing product to others that incorporates the ideas of
GFX-Star, he can and probably WILL sue you for damages and shut down
And since he has hundreds of these installed in the US and Canada, he
has a BIG headstart on you.
Okay, *I* read the documents. It is clear that you must have a separate
storage tank for the GFX-star setup to work 'as advertised'. Only by using
a *cooler* separate storage tank is the setup able to capture the waste heat
from 'batch' drains. Once the storage tank reaches the temperature of the
greywater (or exceeds it in the conventional heater storage tank),
performance will drop off.
This way can effectively 'shift' the heat from outgoing batch drains to a
separate storage tank of fresh-water. So the greywater doesn't have to be
stored, and you can still use the low-maintenance, straight-bore, GFX
For 'best' performance, you would want to route the storage tank outlet to
the 'cold' tap for the shower as well. This looks like their 'tempering
valve' arrangement. But you might be better off routing straight 'cold'
water from the supply directly to sinks and laundry, bypassing the whole
setup for cold supply to those usage points. Otherwise you would be wasting
some of the captured heat on laundry, and who wants a glass of warm water to
drink. Some more plumbing :-(
Someone mentioned some concerns about storage tank of 'warm' water and
Legionarries disease. But if you have treated water, that probably isn't
too much of a concern.
In tests of thousands of water heaters 40% were found to contain
lethal doses of legionella bacteria.
Further testing found that none of the water heaters were gas fired.
Only the electric heated units were the problem below the bottom
I believe as long as the water is moving frequently and/or heated past
96F the legionella is rendered inert.
Well in the Solar Heater Retrofit, HE DOES NOT USE A SEPARATE TANK!!!
In NEW construction easy to do, or in a home with ALL plumbing in the
basement, this is just a few new runs of 'cold' water. I see the
laundry also getting the warm water from the heat exchanger. Only
refrigerator water supply, and sinks get untreated water. Most all the
clothes washing we do is in Warm water, so if that winds up being a bit
warmer than usual, OK.
Its not just Legionnaires, there are an army of bacteria waiting to do
damage. Water with chlorine added, ie city water supplies will be
ok. Well water needs special treatment. My application will be new
construction with a well. All water will be processed thru a Whole
House Filter to get rid of sand and silt. Then it goes thru a
1000gal/day RO with UV to a 350-500 gallon storage tank. A 65psi pump
thn delivers this water to all uses in the house.
Warm water to drink is not good, BUT neither is really cold water
either. Our preference is for cold water, especially in HOT climates.
However we will usually drink MORE water at a time if the water is in
the 60-70F range than in the 40-50F range. The really cold stuff, we
just sip every now and again. A bit warmer and we'll gulp it down.
So in areas that have 40s year round average cold water inlet temp,
treat the WHOLE house to GFX treated water, raising cold water to 65F
helps us drink more water and has no significant affect on cold water
cleaning performance in the laundry.
Note we almost NEVER use the cold cycle in our laundry, so if Warm cycle
water temp changes from 85F to 95F, so what!!!
What working fluid would that be? Water has a much higher heat capacity
than most any other fluid you're likely to find/afford. Best to stick with
As regards to increasing fresh-water flow, the GFX folks recommend plumbing
so that the cold water enters the heat-exchanger *before* splitting to go to
the hot-water heater and the cold tap in the shower. So the 'cold' water
side of the shower is pre-heated (need less 'hot' water to stay comfortable)
as well as the inlet to the hot-water heater. This raises the flow on the
fresh-water side to equal the greywater flow.
Putting a pump to circulate between the 'dip tube' into the heater, and the
drain could improve the circulation through the fresh-water side of the gfx.
But you best be sure to insulate the piping. But with this setup would you
still want the heat-exchanger's fresh-water outlet going to the cold shower
I'm a bit skeptical. After all, the greywater coming in is cooler than the
hot-water heater until you've cooled the bottom of the tank. But the bottom
of the tank is receiving fresh-water out of the hx. Increasing the flow
through the hx with a pump is going to put warm water into the hx inlet,
mixing with the cold water from the main. Then sending the mixture of cold
inlet water, and warm water from the heater drain into the hx. Just so you
can put warmer water back into the bottom of the heater via the 'dip tube'.
Net results seem to be higher flow, but the average temperature of the
fresh-water side of the hx is higher and the greywater outlet temperature
will be higher. I would wonder if the increase in heat transfer due to
higher flow on one side only can make up for the lower temperature
difference across the heat-exchanger walls.
agreed that water is best, but think of Freon as an alternative.
Yes, and this works well in heating dominated climates where ground
water temps average less than 50F year round.
But not here with our ground water already in the high 60s to mid 70s (I
measured mine at 75F)
Yes, as that tempers the water to a reasonable temp. My water will come
from a well, and I need to set my hot water tank to at least 140F to
Foam insulation around piping and the heat exchanger seem to be useful
ideas to conserve energy as does a water heat blanket for the storage tank.
The flow is from the drain plug at the LOW point of the storage tank
thru the pump to mix with fresh water. Then thru the coil, and back in
to the lower third of the storage tank. There will be mixing that
occurs, however, this storage tank should achieve water temps in the
70-90F range depending on entering fresh water temp.
The idea is shown on the web site best under the solar hot water
retrofit. The application data shows efficiency rising as flow rate
thru the coil increases for a given flow rate down the drain.
Grey water temps may NOT increase at all due to the higher flow rate
(same idea as the heat exchanger itself). This higher flow rate comes
at a price of increased pressure loss and expense.
Coil inlet temp will be higher, but then so will coil outlet temp.
Connecting a GFX to a toilet drain is not going to be very sensible,
however, unless you heat your toilet water - makes the most sense when
connected to drains that might have hot water - putting it in the
blackwater stack just adds one more way to have a toilet flush make your
shower uncomfortable, and reduces the potential efficiency by reducing
the temperature differential across the heat exchanger.
Yes, there is no heat to recapture, UNLESS toliet supply is also hooked
to GFX heat exchanger.
The point to adding in the toilets is to make installation simple.
Locate the SINGLE sewer pipe in the basement that collects ALL waste
water, and insert the GFX into the pipe.
Running toilet water to the mix of effluents processed by the system
adds NOTHING to efficiency, but makes installation a BREEZE.
But remember GFX can only recover heat from a 'running water' situation. So
laundry (if you use hot water??), a bathtub, or a sink full of water used to
wash dishes doesn't do *anything* in the GFX. It stores very little heat
for recovery in these 'batch' mode processes.
It really only performs up to it's reputation with showers or if you run
water continuously while doing the dishes or some such.
While Nick's is not as convenient, and it may have some long-term
maintenance issues, it *does* recover/save energy from such batch processes.
But with a total 'storage' of only about 12 gallons, it still wouldn't
really help much in large bath-tub sort of thing (unless you bath in just 12
gallons of water).
Nick would like us to rebalance somewhat.
efficiency 6 8 <give Nick the benefit of the
doubt on higher efficiency
price 5 8 <lower price gets higher points
convenience 8 2 <Nick must separate toilets from
processing, GFX takes ALL
wife friendly 5 1 <GFX almost invisible, Nick's is
a largish stack of 4.5 inch pipe
Maintenance 10 1 <GFX never needs maintenance,
Nick's will need at
least annual cleaning
So use Nick's system if you are on a TIGHT, TIGHT budget and don't mind
the large coil of 4.5 inch black PE pipe in the basement, AND you can
isolate the toilet drains from all other drains.
Nick says GFX needs a toothbrush for cleaning. WHAT???? Its a straight
piece of 3 inch or 4 inch diameter copper pipe from 30 to 60 inches
long that the wastewater flows thru. If it ever needed to be cleaned,
its VERY simple to uncouple the clamps that hold it to the sewer,
disconnect the water (if proper disconnect fittings are installed,
usually not) , take it outside and flush the 3 inch or 4 inch copper
tube with a hose, perhaps running a soapy rag down the inside to rub
anuy residue off. However, the VERY VERY strong flow on the inside
wall of the pipe should keep the inside nearly spotless, subject to ONLY
the normal oxidation of copper in air
I can't as I have a slab foundation and NO basement (plumbing is buried
beneath the slab). The ONLY choice for me is a sewage ejector in the
corner of the garage, near where the main sewer line exits under the
slab with a GFX stack in the corner above the sewage ejector.
You are unaware of the terrain I live in. Ruler flat!!!!
Sewage ejector == PUMP
Yes I could use either one WITH A PUMP as there is NO WAY to intercept
the sewer ABOVE ground. No basements here except in high rise
buildings, certainly not in ANY homes.
In the 1200sq ft living space I have now, the ONLY unit that will work
is the GFX. There is no room for yours UNLESS it goes in the ATTIC!!!
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