Hybrid Car – More Fun with Less Gas

Installation Complete. Coil Insufficient. :-(

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Posted by Brian Graham on October 11, 2005, 5:03 pm
 
It's been a long time in the planning. I finally finished plumbing a DHW system
yesterday. I plan a collector for the roof in the summer, and intend to use heat
the water with my wood stove in the winter.

The plumbing is done. Two 10 foot coils are sitting in air ducts in my wood
stove.  Small line, I grant you. 1/4" . If anything, I expected overheating of
the line to be a problem.

Instead, what I got was essentially a lot of nothing.  :-(   To be precise, the
cold line was definately cold to the touch, and the 'heated' line felt pretty
much line room temperature.

I have shutoffs galore - it looks like, as Chekov might say, a 'Nuclear Wessel'.
I used the shutoffs to route the water through the tank, to the stove, and then
down the house's drain line to the sewar. So, the line is all charged. All air
vented.

I have 2 pressure guages. The first measures town pressure. The guage reads
68psi. The second is 'behind' the pump. (ie, how hard is it working) That guage
goes up about 4-5 psi when I turn the pump on.

I bought a Grundfos 3-speed pump. Nice unit! Very quiet.

I'll drain lines tonight and remove town pressure from the system, and double
check she's pumping properly, though I can't imagine its the problem.

The problem surely has to be the fact that my coils, though brazed together and
sitting flat on the stovetop, simply have 1 point of contact - the bottom of the
coil. The other factor is a baffle inside the stove, but seriously, though the
duct might not be the hottest part of the stove, I wouldn't want to touch it!

Interesting sidenote. I put a chimney thermometer on the stovetop. It's scaled
to 850F. I lit the fire last night - first time for the season - and soon had to
remove the thermometer. The needle was being buried!

I'm thinking making a flat plate from copper for that surface, with 1/2" inlets.
Should be no problem then!

Comments??

Posted by Brian Graham on October 13, 2005, 5:02 pm
 
I've double-checked the pump. Its operating fine. :-)

I've installed a drain on the return line so I can visually see (or measure)
flow.  Through my stove-top coil, 1/4" line, the return flow is perhaps 20% city
pressure..

I need to make a flate plate collector for the stove-top. Ie, something flat for
water to flow through. The higher the surface contact the better..

More to come..
--
Brian

It's been a long time in the planning. I finally finished plumbing a DHW system
yesterday. I plan a collector for the roof in the summer, and intend to use heat
the water with my wood stove in the winter.

The plumbing is done. Two 10 foot coils are sitting in air ducts in my wood
stove.  Small line, I grant you. 1/4" . If anything, I expected overheating of
the line to be a problem.

Instead, what I got was essentially a lot of nothing.  :-(   To be precise, the
cold line was definately cold to the touch, and the 'heated' line felt pretty
much line room temperature.

I have shutoffs galore - it looks like, as Chekov might say, a 'Nuclear Wessel'.
I used the shutoffs to route the water through the tank, to the stove, and then
down the house's drain line to the sewar. So, the line is all charged. All air
vented.

I have 2 pressure guages. The first measures town pressure. The guage reads
68psi. The second is 'behind' the pump. (ie, how hard is it working) That guage
goes up about 4-5 psi when I turn the pump on.

I bought a Grundfos 3-speed pump. Nice unit! Very quiet.

I'll drain lines tonight and remove town pressure from the system, and double
check she's pumping properly, though I can't imagine its the problem.

The problem surely has to be the fact that my coils, though brazed together and
sitting flat on the stovetop, simply have 1 point of contact - the bottom of the
coil. The other factor is a baffle inside the stove, but seriously, though the
duct might not be the hottest part of the stove, I wouldn't want to touch it!

Interesting sidenote. I put a chimney thermometer on the stovetop. It's scaled
to 850F. I lit the fire last night - first time for the season - and soon had to
remove the thermometer. The needle was being buried!

I'm thinking making a flat plate from copper for that surface, with 1/2" inlets.
Should be no problem then!

Comments??



Posted by Brian Graham on October 19, 2005, 8:58 pm
 For anyone that might be reading this thread, outside temperatures have dropped
enough to start running my stove 24x7. Though the coil is small, about 1.5 days
later, my preheat tank is now at 100F.

I still want to put a flat plate on the stovetop instead for fast recovery
rates, but its nice to see things working.   :-)

I still think I can get so much heat from that stove that I'll be able to dump
excess in my air ducts..
--
Brian

I've double-checked the pump. Its operating fine. :-)

I've installed a drain on the return line so I can visually see (or measure)
flow.  Through my stove-top coil, 1/4" line, the return flow is perhaps 20% city
pressure..

I need to make a flate plate collector for the stove-top. Ie, something flat for
water to flow through. The higher the surface contact the better..

More to come..
--
Brian

It's been a long time in the planning. I finally finished plumbing a DHW system
yesterday. I plan a collector for the roof in the summer, and intend to use heat
the water with my wood stove in the winter.

The plumbing is done. Two 10 foot coils are sitting in air ducts in my wood
stove.  Small line, I grant you. 1/4" . If anything, I expected overheating of
the line to be a problem.

Instead, what I got was essentially a lot of nothing.  :-(   To be precise, the
cold line was definately cold to the touch, and the 'heated' line felt pretty
much line room temperature.

I have shutoffs galore - it looks like, as Chekov might say, a 'Nuclear Wessel'.
I used the shutoffs to route the water through the tank, to the stove, and then
down the house's drain line to the sewar. So, the line is all charged. All air
vented.

I have 2 pressure guages. The first measures town pressure. The guage reads
68psi. The second is 'behind' the pump. (ie, how hard is it working) That guage
goes up about 4-5 psi when I turn the pump on.

I bought a Grundfos 3-speed pump. Nice unit! Very quiet.

I'll drain lines tonight and remove town pressure from the system, and double
check she's pumping properly, though I can't imagine its the problem.

The problem surely has to be the fact that my coils, though brazed together and
sitting flat on the stovetop, simply have 1 point of contact - the bottom of the
coil. The other factor is a baffle inside the stove, but seriously, though the
duct might not be the hottest part of the stove, I wouldn't want to touch it!

Interesting sidenote. I put a chimney thermometer on the stovetop. It's scaled
to 850F. I lit the fire last night - first time for the season - and soon had to
remove the thermometer. The needle was being buried!

I'm thinking making a flat plate from copper for that surface, with 1/2" inlets.
Should be no problem then!

Comments??





Posted by Rui Leiria on October 19, 2005, 9:47 pm
 Im seeing your work. I think maybe if you take a coper tube around the
escape smoke , perhaps its more easy.
Regards
Tlicas



Posted by Brian Graham on October 20, 2005, 1:43 pm
 Its something to consider. Its certainly easier to do that than to make a flat
plate collector from sheet metal. But I've found a US supplier for a 4"x5"x10'
copper tube (20 oz - don't know how thick it is) for $5.  Closing the ends with
surplus tube will be easy enough. That would give me 3'x6"=1.5 sq ft of direct
surface contact. Stovetop temperatures hit over 800F when the fire is getting
going, and about 400F when the fire is turned down because the room is quite
warm enough.

On the other hand, the stovepipe is typically at 1/2 of the stovetop
temperature. Surface area of the pipe would be 3.14x3'x6"=4.5 sq ft. Which even
after considering the 50% temp loss when compared to surface temperature is
still 2.25 sq feet - a 50% improvement. BUT, a coil wrapped around the pipe
would not be in contact the whole way up. Only 1 point would be. The rest of the
valley between pipes would have an air gap - read insulator. Still, it may just
do the trick, at a cheaper price and without all the import hassles. The only
downside that comes directly to mind, aside perhaps from esthetics, is that it
would be it would be somewhat difficult to remove for cleaning. But that can be
fixed.

I'll give it some thought.  Thanks for the input.
--
Brian


Im seeing your work. I think maybe if you take a coper tube around the
escape smoke , perhaps its more easy.
Regards
Tlicas



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