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| Author |
Energy transfer systems.
|
|
| JohnH 2005-07-05, 11:25 pm |
| I have a log burner in my lounge. Unfortunately it doesn't spread the heat
around the house. With an overhead fan going I noticed a 10 degree C
difference between the lounge and bedrooms (doors open). I could put a fan
in the wall to blow into the hall or a transfer system through the roof
space and into the bedrooms. I tend to think though that the ones from the
hardware store are for dummies. They are foil line, wrapped in a fluffy
insulating material such as this:
http://www.securimax.co.nz/heat.htm
I'm not an engineer but I imagine the amount of heat transferred will
depend on the ratio of the surface area of the pipe to the fluffy material.
A polystyrene pipe would be "serious" insulation.
What do you think?
Thanks
John
| |
| Anthony Matonak 2005-07-06, 4:25 am |
| JohnH wrote:
quote:
> I have a log burner in my lounge. Unfortunately it doesn't spread the heat
> around the house. With an overhead fan going I noticed a 10 degree C
> difference between the lounge and bedrooms (doors open). I could put a fan
> in the wall to blow into the hall or a transfer system through the roof
> space and into the bedrooms. I tend to think though that the ones from the
> hardware store are for dummies. They are foil line, wrapped in a fluffy
> insulating material such as this:
> http://www.securimax.co.nz/heat.htm
> I'm not an engineer but I imagine the amount of heat transferred will
> depend on the ratio of the surface area of the pipe to the fluffy material.
> A polystyrene pipe would be "serious" insulation.
> What do you think?
....
I would think that the heat transferred will depend on the amount
(volume) of air moved and how hot it is. The insulation on the pipe
simply keeps the hot air hot, as it will lose heat through the pipe
to the uninsulated ceiling space. More insulation on this pipe will
then mean you lose less heat when you move the air.
In your case, I'd think that placing the inlet as close to the log
burner as possible will give you the hottest air. Perhaps you could
even have a duct wrapped around the chimney. Then get a blower that
can move the most air. Perhaps even a multi-speed blower so it can
be adjusted if it's blowing too much or too loud. Larger ducts/pipes
might allow the moving of more air.
Anthony
| |
| nicksanspam@ece.villanova.edu 2005-07-06, 12:25 pm |
| Anthony Matonak <anthonym40@nothing.like.comcast.net> wrote:
quote:
>I would think that the heat transferred will depend on the amount
>(volume) of air moved and how hot it is.
Sure. Btu/h = 1.08cfmdT, with dT (F), and kW = 1.2m^3/sdT, with dT (C), so
a 500 cfm (0.236 m^3/s) fan moving 80 F (26.7 C) air into a 70 F (21.1 C)
room moves 1.08x500(80-10) = 5400 Btu/h or 1.2x0.236(26.7-21.1) = 1.6 kW
of heat power.
Nick
| |
|
| Also think carefulyl about the quality of the aire you will be moving,=20
and the air currents you will be creating - ducting hot combustion air=20
into a bedroom could lead to headaches if their isn't adequate oxygen=20
coming in from another source. (so maybe you will need "fresh air" from=20
another source... and if it is colder than ambient temperature in the=20
bedroom your not going to be heating the room much!)
Be aware also that you will be creating more air currents in the room=20
with the heater as well, as the air being ducted out will need to be=20
replaced as well, and that air currents generally lead to a "feeling"=20
that the temperature is lower than it really is.
The figures that I hear mentioned the most often (retrofit duct sellors, =
installers, energy councilors) are between a 5% and 10% temperature=20
increase if everything works correctly. So 1=B0 to 2=B0 in the best case.=
I'm sure others have some practicle experience?
Mel
nicksanspam@ece.villanova.edu a =E9crit :
quote:
> Anthony Matonak <anthonym40@nothing.like.comcast.net> wrote:
>=20
>=20
>=20
>=20
> Sure. Btu/h =3D 1.08cfmdT, with dT (F), and kW =3D 1.2m^3/sdT, with dT =
(C), so
quote:
> a 500 cfm (0.236 m^3/s) fan moving 80 F (26.7 C) air into a 70 F (21.1 =
C)
quote:
> room moves 1.08x500(80-10) =3D 5400 Btu/h or 1.2x0.236(26.7-21.1) =3D 1=
=2E6 kW
quote:
> of heat power.=20
>=20
> Nick
>=20
| |
| JohnH 2005-07-06, 11:25 pm |
| Yjis would be more like 24C to 14C. Does the R value of the insulation
figure much?
John
<nicksanspam@ece.villanova.edu> wrote in message
news:dagb2m$chs@acadia.ece.villanova.edu...
quote:
> Anthony Matonak <anthonym40@nothing.like.comcast.net> wrote:
>
>
> Sure. Btu/h = 1.08cfmdT, with dT (F), and kW = 1.2m^3/sdT, with dT (C), so
> a 500 cfm (0.236 m^3/s) fan moving 80 F (26.7 C) air into a 70 F (21.1 C)
> room moves 1.08x500(80-10) = 5400 Btu/h or 1.2x0.236(26.7-21.1) = 1.6 kW
> of heat power.
>
> Nick
>
| |
| JohnH 2005-07-06, 11:25 pm |
| IT seems that heaters such as log burners are only any good if they are
heating a large area (eg open plan); if your too cold you can move closer
(and vice versa); wheras in a smaller room if you get too hot that is as bad
as getting too cold.
My father rigged a heat transfer system from his lounge to the bathroom
(about 4 meters). It went in very hot and came out quite cool (by
comparison)
John
"Mel" <melodie@pasdespam.chezmoi> wrote in message
news:42cbb61d$0$32342$636a15ce@news.free.fr...
Also think carefulyl about the quality of the aire you will be moving,
and the air currents you will be creating - ducting hot combustion air
into a bedroom could lead to headaches if their isn't adequate oxygen
coming in from another source. (so maybe you will need "fresh air" from
another source... and if it is colder than ambient temperature in the
bedroom your not going to be heating the room much!)
Be aware also that you will be creating more air currents in the room
with the heater as well, as the air being ducted out will need to be
replaced as well, and that air currents generally lead to a "feeling"
that the temperature is lower than it really is.
The figures that I hear mentioned the most often (retrofit duct sellors,
installers, energy councilors) are between a 5% and 10% temperature
increase if everything works correctly. So 1° to 2° in the best case.
I'm sure others have some practicle experience?
Mel
nicksanspam@ece.villanova.edu a écrit :
quote:
> Anthony Matonak <anthonym40@nothing.like.comcast.net> wrote:
>
>
>
>
> Sure. Btu/h = 1.08cfmdT, with dT (F), and kW = 1.2m^3/sdT, with dT (C), so
> a 500 cfm (0.236 m^3/s) fan moving 80 F (26.7 C) air into a 70 F (21.1 C)
> room moves 1.08x500(80-10) = 5400 Btu/h or 1.2x0.236(26.7-21.1) = 1.6 kW
> of heat power.
> Nick
>
| |
|
| In article <42cb333b@clear.net.nz>, "JohnH" <89s@yahoo.com.au> wrote:
quote:
> I have a log burner in my lounge. Unfortunately it doesn't spread the heat
> around the house. With an overhead fan going I noticed a 10 degree C
> difference between the lounge and bedrooms (doors open). I could put a fan
> in the wall to blow into the hall or a transfer system through the roof
> space and into the bedrooms. I tend to think though that the ones from the
> hardware store are for dummies. They are foil line, wrapped in a fluffy
> insulating material such as this:
> http://www.securimax.co.nz/heat.htm
> I'm not an engineer but I imagine the amount of heat transferred will
> depend on the ratio of the surface area of the pipe to the fluffy material.
> A polystyrene pipe would be "serious" insulation.
> What do you think?
> Thanks
> John
>
>
Why move all that air around? Why not put a couple of turns of copper
tubing inside the firebox and move the heat with PolyGlycol to a
radiator in the bedrooms, via PVC Pipe, or a Hydronic Floor Tube System.
One could actually Thermalsyphan the whole system and have no moving
parts excpt maybe a small 12Vdc Brushless Fan on the radiators in the
bedrooms. Much more efficent then a stove/air heat exchanger.
Me
| |
| John P Bengi 2005-07-06, 11:25 pm |
| Can you say "Still explosion"?
"Me" <Me@shadow.orgs> wrote in message
news:Me-D31D5A.15491106072005@netnews.worldnet.att.net...
quote:
> In article <42cb333b@clear.net.nz>, "JohnH" <89s@yahoo.com.au> wrote:
>
heat[vbcol=seagreen]
fan[vbcol=seagreen]
the[vbcol=seagreen]
material.[vbcol=seagreen]
>
> Why move all that air around? Why not put a couple of turns of copper
> tubing inside the firebox and move the heat with PolyGlycol to a
> radiator in the bedrooms, via PVC Pipe, or a Hydronic Floor Tube System.
> One could actually Thermalsyphan the whole system and have no moving
> parts excpt maybe a small 12Vdc Brushless Fan on the radiators in the
> bedrooms. Much more efficent then a stove/air heat exchanger.
>
> Me
| |
| Kiwi John 2005-07-06, 11:25 pm |
| a friend of mine made rads out of copper tube and directly coupled to the
heat coil left a valve to get rid of any air in the system has worked for
over 12 years how heats his whole hall way really well so could be expanded
on
if you put a tank in the roof and a pump on it you could heat the water in
the tank and use a small pump to move it around
"Me" <Me@shadow.orgs> wrote in message
news:Me-D31D5A.15491106072005@netnews.worldnet.att.net...
quote:
> In article <42cb333b@clear.net.nz>, "JohnH" <89s@yahoo.com.au> wrote:
>
>
> Why move all that air around? Why not put a couple of turns of copper
> tubing inside the firebox and move the heat with PolyGlycol to a
> radiator in the bedrooms, via PVC Pipe, or a Hydronic Floor Tube System.
> One could actually Thermalsyphan the whole system and have no moving
> parts excpt maybe a small 12Vdc Brushless Fan on the radiators in the
> bedrooms. Much more efficent then a stove/air heat exchanger.
>
> Me
| |
| JohnH 2005-07-07, 12:25 pm |
| One problem is that log burners have to be non polluting.
Cooling the fire box makes them smoke more(?)
John
"Kiwi John" <therileys@ihug.com.au> wrote in message
news:42cc82f1$0$21464$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
quote:
>a friend of mine made rads out of copper tube and directly coupled to the
>heat coil left a valve to get rid of any air in the system has worked for
>over 12 years how heats his whole hall way really well so could be expanded
>on
> if you put a tank in the roof and a pump on it you could heat the water in
> the tank and use a small pump to move it around
>
>
> "Me" <Me@shadow.orgs> wrote in message
> news:Me-D31D5A.15491106072005@netnews.worldnet.att.net...
>
>
| |
| Nick Pine 2005-07-07, 6:25 pm |
| JohnH <89s@yahoo.com.au> wrote:
quote:
>One problem is that log burners have to be non polluting.
>Cooling the fire box makes them smoke more(?)
One solution is to extract the heat from the chimney, with a forced draft
to ensure the lower-temp smoke goes up the chimney. A condensing chimney
might add 15% to the woodstove's efficiency.
Nick
| |
| nicksanspam@ece.villanova.edu 2005-07-07, 6:25 pm |
| Mel <melodie@pasdespam.chezmoi> wrote:
quote:
>Also think carefulyl about the quality of the aire you will be moving,=20
>and the air currents you will be creating - ducting hot combustion air=20
>into a bedroom could lead to headaches if their isn't adequate oxygen=20
>coming in from another source.
Combustion air should go up a chimney.
quote:
>Be aware also that you will be creating more air currents in the room=20
>with the heater as well, as the air being ducted out will need to be=20
>replaced as well, and that air currents generally lead to a "feeling"=20
>that the temperature is lower than it really is.
IMO, that's unlikely to be a problem, if the return air flows back into
the heater room through a large area like an open door. And contrary to
popular belief, it looks hard to make the room being heated uncomfortable
by moving a airstream into the room, if it's warmer than 74 F or so. The
ASHRAE 55-2004 calc below indicates it would take about 70 mph (!) of 76 F
air to make someone feel cooler than 0 mph at 70 F, if they are dressed
in ordinary indoor winter clothing.
quote:
>The figures that I hear mentioned the most often (retrofit duct sellors, =
>installers, energy councilors) are between a 5% and 10% temperature=20
>increase if everything works correctly. So 1=B0 to 2=B0 in the best case.=
You can figure this more exactly using "Ohm's law for heatflow."
If we move 500 cfm of 72 F air into an 8' cubical room with 2 US
R20 walls and an R20 ceiling exposed to 30 F outdoor air, we have
something like this, with a Tr = 71.3 F destination room temp:
Tr = 30+(72-30)/(0.00185+0.104)x0.104 = 71.3 F
|
|
1/(1.08x500) | 20/(3x8x8)
72 F -----www------------www----- 30 F
= 0.00185 = 0.104
Nick
20 CLO = 1'clothing insulation (clo)
30 MET=1.1'metabolic rate (met)
40 WME=0'external work (met)
50 RH=50'relative humidity (%)
60 DATA 70,0
70 DATA 72,0.528
80 DATA 74,1.54
90 DATA 76,5.88
100 DATA 78,69.8
110 FOR CASE = 1 TO 5
120 READ TC,MPH'read temp (F) and air velocity (mph)
130 TA=(TC-32)/1.8'air temp (C)
140 TR=TA'mean radiant temp (C)
150 VEL=.447*MPH'air velocity (m/s)
160 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa
170 PA=RH*10*FNPS(TA)'water vapor pressure, Pa
180 ICL=.155*CLO'clothing resistance (m^2K/W)
190 M=MET*58.15'metabolic rate (W/m^2)
200 W=WME*58.15'external work in (W/m^2)
210 MW=M-W'internal heat production
220 IF ICL<.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor
230 HCF=12.1*SQR(VEL)'forced convection conductance
240 TAA=TA+273'air temp (K)
250 TRA=TR+273'mean radiant temp (K)
260 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp
270 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermediate values
280 P5=308.7-.028*MW+P2*(TRA/100)^4
290 XN=TCLA/100
300 XF=XN
310 N=0'number of iterations
320 EPS=.00015'stop iteration when met
330 XF=(XF+XN)/2'natural convection conductance
340 HCN=2.38*ABS(100*XF-TAA)^.25
350 IF HCF>HCN THEN HC=HCF ELSE HC=HCN
360 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)
370 N=N+1
380 IF N>150 GOTO 500
390 IF ABS(XN-XF)>EPS GOTO 330
400 TCL=100*XN-273'clothing surface temp (C)
410 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin
420 IF MW>58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating
430 HL3=.000017*M*(5867-PA)'latent respiration heat loss
440 HL4=.0014*M*(34-TA)'dry respiration heat loss
450 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation
460 HL6=FCL*HC*(TCL-TA)'heat loss by convection
470 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient
480 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote
490 GOTO 510
500 PMV=99999!:PPD=100
510 PRINT TC,MPH,PMV
520 NEXT CASE
Air Air Comfort level
temp (F) vel (mph) (-3 to 3 scale)
70 0 -.2857543
72 .528 -.2853797
74 1.54 -.2856358
76 5.88 -.2852426
78 69.8 -.2856257
Innova AirTech Instruments has an excellent comfort web site...
http://www.impind.de.unifi.it/Impin...tica/materiale/
microclima/innova/thermal.htm
| |
| daestrom 2005-07-07, 11:25 pm |
|
"Nick Pine" <nick@acadia.ece.villanova.edu> wrote in message
news:dajbtj$dcq@acadia.ece.villanova.edu...
quote:
> JohnH <89s@yahoo.com.au> wrote:
>
>
> One solution is to extract the heat from the chimney, with a forced draft
> to ensure the lower-temp smoke goes up the chimney. A condensing chimney
> might add 15% to the woodstove's efficiency.
>
Depending what you're burning, that can be a *BAD* idea. If you're burning
logs, cooling the flue to the condensation point will condense out a lot
more than just water. The result can be a dangerous amount of creosote and
tar build up that leads to a fire on your 'condenser'.
Not to mention the very corrosive nature of the condensate.
daestrom
| |
| Anthony Matonak 2005-07-07, 11:25 pm |
| daestrom wrote:
quote:
> "Nick Pine" <nick@acadia.ece.villanova.edu> wrote in message
>
>
> Depending what you're burning, that can be a *BAD* idea. If you're burning
> logs, cooling the flue to the condensation point will condense out a lot
> more than just water. The result can be a dangerous amount of creosote and
> tar build up that leads to a fire on your 'condenser'.
>
> Not to mention the very corrosive nature of the condensate.
Perhaps something could be done with tar and creosote before it
gets to the chimney. Don't many wood burners these days have
catalytic converters or secondary combustion chambers to burn
off these things?
Stainless steel seems to be common enough on auto exhaust systems.
I don't see why the flue couldn't be made out of stainless steel,
at least on the inside. It shouldn't cost all that much more and
should make it hold up against corrosive materials better.
Anthony
| |
| nicksanspam@ece.villanova.edu 2005-07-08, 12:25 pm |
| daestrom <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
quote:
>
>...If you're burning logs, cooling the flue to the condensation point will
>condense out a lot more than just water. The result can be a dangerous
>amount of creosote and tar build up that leads to a fire on your 'condenser'.
Not if it all drips down into a plastic bucket.
Nick
| |
| daestrom 2005-07-08, 12:25 pm |
|
"Anthony Matonak" <anthonym40@nothing.like.comcast.net> wrote in message
news:tPadnd6wUtZlWFDfRVn-oA@comcast.com...
quote:
> daestrom wrote:
>
> Perhaps something could be done with tar and creosote before it
> gets to the chimney. Don't many wood burners these days have
> catalytic converters or secondary combustion chambers to burn
> off these things?
>
Yes, this is possible. Depending on the exact quality of the unit it may
have a catalytic converter. Does the flue gas have to be up to a certain
temperature for it to work? Is the cooling coil in the chimney after the
converter? Lots of details need to be looked at, not just a simple coil
around the flue of a woodstove.
quote:
> Stainless steel seems to be common enough on auto exhaust systems.
> I don't see why the flue couldn't be made out of stainless steel,
> at least on the inside. It shouldn't cost all that much more and
> should make it hold up against corrosive materials better.
>
That's also possible. I haven't seen too many chimney flues made of
stainless though. And the draft blower would need to be either at the far
end of the 'condensing chimney' where only cool gasses flow through it. Or
on the inlet side. But inlet side means a pressurized fire-box and most
woodstove/ burners that are designed for natural draft won't be tight enough
to support a pressurized fire-box and keep CO out of the home.
It's certainly *possible*, but there are a lot of little things to think of
before you just wrap some copper tubing all the way up your chimney, or put
a large cooling coil in the flue.
daestrom
| |
| daestrom 2005-07-08, 12:25 pm |
|
<nicksanspam@ece.villanova.edu> wrote in message
news:dalgi8$e1u@acadia.ece.villanova.edu...
quote:
> daestrom <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
>
>
> Not if it all drips down into a plastic bucket.
>
Tar is more likely to build up on your 'coil' and block off the air flow.
When it cools it quickly thickens to the point of not 'dripping' very well.
Chimney fires are often caused by a buildup of tar and creosote on the
interior of the liner, and then on a particularly cold day the homeowner
builds a 'roaring good fire' to take off the chill. Heats the chimney tar,
a few sparks, and a fire in the flue that can burn through the liner.
daestrom
| |
| nicksanspam@ece.villanova.edu 2005-07-08, 12:25 pm |
| daestrom <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
quote:
[vbcol=seagreen]
>Tar is more likely to build up on your 'coil' and block off the air flow.
I disagree.
Nick
| |
|
| In article <rbtze.12796$e%5.4973@twister.nyroc.rr.com>,
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
quote:
> "Anthony Matonak" <anthonym40@nothing.like.comcast.net> wrote in message
> news:tPadnd6wUtZlWFDfRVn-oA@comcast.com...
>
> Yes, this is possible. Depending on the exact quality of the unit it may
> have a catalytic converter. Does the flue gas have to be up to a certain
> temperature for it to work? Is the cooling coil in the chimney after the
> converter? Lots of details need to be looked at, not just a simple coil
> around the flue of a woodstove.
>
>
> That's also possible. I haven't seen too many chimney flues made of
> stainless though. And the draft blower would need to be either at the far
> end of the 'condensing chimney' where only cool gasses flow through it. Or
> on the inlet side. But inlet side means a pressurized fire-box and most
> woodstove/ burners that are designed for natural draft won't be tight enough
> to support a pressurized fire-box and keep CO out of the home.
>
> It's certainly *possible*, but there are a lot of little things to think of
> before you just wrap some copper tubing all the way up your chimney, or put
> a large cooling coil in the flue.
>
> daestrom
>
>
After reading all the post in this thread, I would just point out that
If one were to put the Copper Pipe coil in the firebox, you really don't
have to worry about cooling the flue gases, because your extracting the
energy before the gases get to the flue. It would be the same as not
building a big enough fire in the first place. I have a small 5 turn
1/2" Copper Pipe Coil that is built into the bottom section of my 6"
cooking woodstove stack at my cabin that thermalsyphans hot water
into a 60 Gallon tank. By the time you finished cooking dinner, you
have enough hot water to do the dishes. The stack is 12Ft straight up
and shows no sign of excessive buildup of any exhaust products in 10
years. We burn spruce, and alder. Out here in the alaskan bush, this
type of water heater is very common, with some of the coils inside the
firebox, some in the Stack, and some thermally bonded to the Iron sides
of the woodburner heaters. Cold water in the bottom, and hot water out
the top, with single heat source.
Moving the BTU's to another room would be trival with a hydronic floor
heating system or even a radiator system. I know of both styles in use
in cabins around here. One guy uses the concrete slab foundation of his
cabin as a heatsink/storage and uses a heat exchanger on his diesel
genset to recover all the cooling btu's and about 1/2 the exhaust BTU's
to drive the system. His cabin is heated with glycol hydronic heating
loops in the floors, inside the insulated building. Even his small genset
(3kw) puts out enough BTU's to keep the place warm most of the year,
and he keeps his inverter batteries charged up all at the same time.
Me
| |
| andre_54005@yahoo.com 2005-07-08, 6:25 pm |
| In some boiler installations, both stationary and on ships I believe,
instead of trying to seal the furnace/s would just pressurize the
entire room.
____________
Andre' B.
| |
| nicksanspam@ece.villanova.edu 2005-07-08, 6:25 pm |
| Me <Me@shadow.orgs> wrote:
quote:
>After reading all the post in this thread, I would just point out that
>If one were to put the Copper Pipe coil in the firebox, you really don't
>have to worry about cooling the flue gases, because your extracting the
>energy before the gases get to the flue...
IMO, that would collect crud on the coil and lower the firebox temp,
which lowers efficiency and raises pollution.
We might use two fluepipes and a fan to make a condensing chimney and
counterflow heat exchanger with combustion gases in the inner pipe and
a mixture of outdoor and room air moving towards the stove in the space
between the pipes and exiting to the room near the stove. If we condense
water vapor in the inner pipe, we may never get dry creosote buildup there.
Nick
| |
| Tim Thomson 2005-07-09, 6:25 pm |
| nicksanspam@ece.villanova.edu wrote:
quote:
> Me <Me@shadow.orgs> wrote:
>
>
> IMO, that would collect crud on the coil and lower the firebox temp,
> which lowers efficiency and raises pollution.
>
> We might use two fluepipes and a fan to make a condensing chimney and
> counterflow heat exchanger with combustion gases in the inner pipe and
> a mixture of outdoor and room air moving towards the stove in the space
> between the pipes and exiting to the room near the stove. If we condense
> water vapor in the inner pipe, we may never get dry creosote buildup there.
>
> Nick
I burn wet wood,dry wood, any wood I can get my hands on in my air tight stove.
I get majour soot build up. Doesn't bother me at all. I made the stove pipe
real easy to clean once a week or once a month if need be every second day.
I just grab the pipe with a hug like grip lift swing it away from the stove
and shove my brush up and down a couple of times. Clean up is done with the
vacuflo. Takes about 5 mins. The only time I go onto the roof is in the summer
just too have a look.
I am going to be installing a coil for water circ inside the fire box this
winter anyone know whats the best type of pipe from the local hardware or junk
yard?
| |
|
| In article <damo4e$ejm@acadia.ece.villanova.edu>,
nicksanspam@ece.villanova.edu wrote:
quote:
> IMO, that would collect crud on the coil and lower the firebox temp,
> which lowers efficiency and raises pollution.
Only if you don't build a big enough fire in the stove. How is it that
you can use these BTU's for heating the air around a woodstove, but
can't use the same BTU's for heating water in a copper pipe inside the
firebox. One would wonder if the Stack Gas Temp was near the same in
both situations, what the problem could possibly be? If the Stack Temp
is to low for efficent burning, add smaller chunks of wood, and more of
them? This isn't "Rocket Science", and woodstove thermaldynamics has
been well understood since "Moses came down off the mountain......."
Me
| |
| Bruce in Alaska 2005-07-09, 11:25 pm |
| In article <oARze.1918386$Xk.1465980@pd7tw3no>,
Tim Thomson <"thomsontim"@shaw.ca@shaw.ca> wrote:
quote:
> nicksanspam@ece.villanova.edu wrote:
>
>
> I burn wet wood,dry wood, any wood I can get my hands on in my air tight
> stove.
>
> I get majour soot build up. Doesn't bother me at all. I made the stove pipe
> real easy to clean once a week or once a month if need be every second day.
> I just grab the pipe with a hug like grip lift swing it away from the stove
> and shove my brush up and down a couple of times. Clean up is done with the
> vacuflo. Takes about 5 mins. The only time I go onto the roof is in the
> summer
> just too have a look.
>
>
> I am going to be installing a coil for water circ inside the fire box this
> winter anyone know whats the best type of pipe from the local hardware or
> junk
> yard?
>
Hard Drawn Copper Tubing run thru a bender to form what will fit in your
firebox, is what we have always used around this part of the world.
Connections can be made to the coil external to the stove with silver
solder to Copper/NPT Galvinized Waterpipe. I usually get 7 to 10 years
out of a Firebox Coil before the thing losses efficency due to Hard
Water Buildup inside the coil. Takes a few hours to do a coil change,
and I keep a couple spares around in case of a failure of some kind.
Bruce in alaska
--
add a <2> before @
| |
| nicksanspam@ece.villanova.edu 2005-07-09, 11:25 pm |
| Me <Me@shadow.orgs> wrote:
quote:
>...How is it that you can use these BTU's for heating the air around
>a woodstove, but can't use the same BTU's for heating water in a copper
>pipe inside the firebox.
You can heat air around a 600 F woodstove, but
water keeps the pipe temp less than 212 F.
quote:
>...woodstove thermaldynamics has been well understood since "Moses came
>down off the mountain......."
Can Moses help you understand "woodstove thermaldynamics"? :-)
1. Thou shalt not lower the firebox temperature...
Nick
| |
|
| In article <dapomr$f59@acadia.ece.villanova.edu>,
nicksanspam@ece.villanova.edu wrote:
quote:
> Me <Me@shadow.orgs> wrote:
>
>
> You can heat air around a 600 F woodstove, but
> water keeps the pipe temp less than 212 F.
>
>
> Can Moses help you understand "woodstove thermaldynamics"? :-)
>
> 1. Thou shalt not lower the firebox temperature...
>
> Nick
>
Maybe you should try it, before you speak.....We have been using this
method of heating our water for many years, without any unreasonable
problems. Check any remote cabin in alaska and you'll find a similar
system in place for hot water. Clearly it works, and for multiple
systems, it works very well.....Of course maybe the Laws of
thermaldynamics are different where you live. one must wonder......
Me
| |
| daestrom 2005-07-11, 11:25 pm |
|
<nicksanspam@ece.villanova.edu> wrote in message
news:dapomr$f59@acadia.ece.villanova.edu...
quote:
> Me <Me@shadow.orgs> wrote:
>
>
> You can heat air around a 600 F woodstove, but
> water keeps the pipe temp less than 212 F.
>
>
> Can Moses help you understand "woodstove thermaldynamics"? :-)
>
> 1. Thou shalt not lower the firebox temperature...
>
Any proof of this article of faith??
daestrom
| |
| nicksanspam@ece.villanova.edu 2005-07-12, 12:25 pm |
| daestrom <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
quote:
>
>Any proof of this article of faith??
I've read that lowering the firebox temp makes combustion less complete,
with more unburned combustable products and more pollution in the exhaust.
It's basic "woodstove thermaldynamics" :-)
Nick
| |
| daestrom 2005-07-12, 11:25 pm |
|
<nicksanspam@ece.villanova.edu> wrote in message
news:db08ro$gg1@acadia.ece.villanova.edu...
quote:
> daestrom <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
>
>
> I've read that lowering the firebox temp makes combustion less complete,
> with more unburned combustable products and more pollution in the exhaust.
>
> It's basic "woodstove thermaldynamics" :-)
Hmm.... 'basic thermo[al]dynamics' uh, yeah.
Most commercial boilers are lined with 'water-wall' tubes. These tubes
block the radiant energy from the fire from reaching the fire-brick behind
the wall tubes and collect the energy in water. I'm sure the thermodynamics
of this are an improvement over standard fire-brick-only boiler walls.
Lining the walls with tubing to collect heat does little to reduce the
temperature of the flame and its combustion efficiency. It *does* however
reduce the heat energy put into the walls of the firebox. In the case of a
wood stove, this means less heat transferred through the casing into the
room in the immediate vicinity of the stove. But this isn't a loss since
the energy is now in the tube water where it can easily be transported to
another useful location. In a commercial boiler, it means less losses out
the casing and more water pre-heated, ready for the steam-generating tubes.
Putting a coil in the flow path of combustion gasses can be different. If
it cools the gasses significantly, you may have a problem with condensing
all sorts of volital components (unless they were 'burned' in a catalytic
converter), and reducing the overall draft (may need mechanical assistance).
Putting tubing right in the grate or right above it in the flame itself
*will* reduce combustion efficiency. Could lead to a much higher portion of
the fuel gasses not burning completely and raise fuel consumption. Can also
result in a burn-through with the steam/water leaking into the firebox (even
with water in the tube, an extreme flame temperature can cause local
dry-out).
Although basic 'woodstove thermodynamics' may have been around since Moses,
a good understanding of how combustion works and firebox design weren't
advanced until the mid 1800's as the use of steam power rose. The use of
multiple tubes (either fire-tube, or water-tube) wasn't introduced until
then.
The time of Moses used fireplaces for cooking and heating. Open-hearth
fireplaces were common up through the medieval ages.
daestrom
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