Posted by Bob F on November 1, 2009, 9:09 pm
Bruce in alaska wrote:
>> Nice, I want to take hot water off my wood stove also which is the
>> primary heat source for the cabin and was wondering about wrapping
>> the copper outside or inside the pipe. I want to use convection to
>> circulate it also. Do you have any drawings or photos of your
>> design?
>>
>> Mike
> What I did was make up the Copper Tubing Coil by packing the tube with
> sand, and then bending it around a wood mandrel that was turned down,
> so as to have the Outside diameter of the coil at 5 - 15/16ths
> inches. Once the bending is done, (the sand keeps the tubing from
> kinking during the bending process) I remove the sand, and wash out
> the tubing with water. Then I silver soldered a 90 degree elbow on
> each end to bring the water out thru the Stainless Stovepipe. Now
> that I have the coil built, I take my section of Stovepipe, and break
> the seam, so I can roll it out flat, and measure where to put the two
> holes for the Pipes to come thru, I then used a 1/2" Greeley Punch to
> make the hole just slightly larger than the Copper Pipe elbows, and
> install the coil, with elbows thru the holes using the Woodstove
> Gasket Rope to make an exhaust tight fitting. Then I reroll the
> Stovepipe around the coil, and reset the Seam top to bottom. I then
> silver soldered two 3" pieces of tubing, with Copper Unions on the
> other end, to the other outside ends of the elbows, so that I could
> disconnect the water system from the Stack Coil when Service, or
> Stovepipe Cleaning (which I do annually) is required. On the other
> side Copper Unions I have Ball Valves, so I can isolate the Water
> system, without draining it, during Servicing. I usually try to place
> this section of Stovepipe as close to the stove as possible, so that
> it has access to the most BTU's in the flue.
How does this heat exchanger affect stovepipe cleaning? Is creosote buildup on
the exchanger a big problem?
Do you electrically insulate the copper from the stainless to avoid corrosion?
Posted by Bruce in alaska on November 2, 2009, 6:08 pm
>
> How does this heat exchanger affect stovepipe cleaning? Is creosote buildup
> on
> the exchanger a big problem?
>
> Do you electrically insulate the copper from the stainless to avoid
> corrosion?
Since this Stovepipe connects to a Metal-Bestous Chimney we take the
uninsulated sections out while cleaning the chimney, which necessitates
the disconnection of the Heating Coil. Usually we just bang on the
outside of these sections to knock all the soot off the insides while
cleaning. Not really much buildup other that LampBlack Soot....
Nope, never had a significant problem in the 2 decades the coil has been
in use. Biggest problem we have seen is we have to replace the coil
every ten years or so due to Calcite buildup inside, caused by hard
water....
--
Bruce in alaska
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Posted by Bruce in alaska on October 30, 2009, 7:39 pm
In article
> > > in a stationary instalation) of tapping off "free" waste heat from the hot
> > > coolant.
> >
> > thanks for that, can you tell more?
>
> The biggest amount of heat you can recover from an IC engine is from
> the exhaust. You would need a stainless steel (or other non corrosive
> material) heat exchanger and would heat water.
> 75% of the energy available from the fuel goes down the exhaust pipe.
> Heat from the oil can also be recovered in large setups.
It would seem that your figures above, are a bit suspect. Where do they
come from? The Rule of Thumb, for Diesel Engines, has always been the
1/3, 1/3, 1/3 Rule. 33% of the fuel BTU's goes arf1656331a13ae out the
Crankshaft, 33% of the BTU's goes out the Cooling System, and 33% of the
BTU's go up the Stack. 75-85% of the Cooling BTU's are recoverable in a
Liquid Cooled engine, and about 50% of the Exhaust BTU's are Recoverable
when using a Marine type Water Jacketed Exhaust Manifold. This makes, on
average, between 70-80% of the Fuel BTU's useful in an efficiently
designed Co-Gen operation using a Liquid Cooled Diesel Genset. I find in
practice that these are fairly close to real world numbers.
--
Bruce in alaska
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Posted by harry on November 1, 2009, 8:05 pm
> In article
> > > > in a stationary instalation) of tapping off "free" waste heat from the
hot
> > > > coolant.
> > > thanks for that, can you tell more?
> > The biggest amount of heat you can recover from an IC engine is from
> > the exhaust. You would need a stainless steel (or other non corrosive
> > material) heat exchanger and would heat water.
> > 75% of the energy available from the fuel goes down the exhaust pipe.
> > Heat from the oil can also be recovered in large setups.
> It would seem that your figures above, are a bit suspect. Where do they
> come from? The Rule of Thumb, for Diesel Engines, has always been the
> 1/3, 1/3, 1/3 Rule. 33% of the fuel BTU's goes arf1656331a13ae out the
> Crankshaft, 33% of the BTU's goes out the Cooling System, and 33% of the
> BTU's go up the Stack. 75-85% of the Cooling BTU's are recoverable in a
> Liquid Cooled engine, and about 50% of the Exhaust BTU's are Recoverable
> when using a Marine type Water Jacketed Exhaust Manifold. This makes, on
> average, between 70-80% of the Fuel BTU's useful in an efficiently
> designed Co-Gen operation using a Liquid Cooled Diesel Genset. I find in
> practice that these are fairly close to real world numbers.
> --
> Bruce in alaska
> add <path> after <fast> to reply
This would be the upper limit, not achievable in practice.
Bit here on the topic about the maximum theoretical efficiency of heat
engines.
http://en.wikipedia.org/wiki/Carnot_cycle
Posted by Bruce in alaska on October 25, 2009, 8:40 pm
> see http://www.poweredgenerators.com/honda/ES6500.html
>
> is the water cooling better for a hot, humid climate to prolong engine life?
> same model is available without water cooling, does that mean engine
> overheats?
Water cooling tends to keep the engine temps more stable and uniform
across the entire Block, where as Air Cooling will tend to have Hot
Spots, which can cause wear problems. also as Vaughn states, Water
Cooling gives the operator more opportunities for co-Genertion.
--
Bruce in alaska
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>> primary heat source for the cabin and was wondering about wrapping
>> the copper outside or inside the pipe. I want to use convection to
>> circulate it also. Do you have any drawings or photos of your
>> design?
>>
>> Mike
> What I did was make up the Copper Tubing Coil by packing the tube with
> sand, and then bending it around a wood mandrel that was turned down,
> so as to have the Outside diameter of the coil at 5 - 15/16ths
> inches. Once the bending is done, (the sand keeps the tubing from
> kinking during the bending process) I remove the sand, and wash out
> the tubing with water. Then I silver soldered a 90 degree elbow on
> each end to bring the water out thru the Stainless Stovepipe. Now
> that I have the coil built, I take my section of Stovepipe, and break
> the seam, so I can roll it out flat, and measure where to put the two
> holes for the Pipes to come thru, I then used a 1/2" Greeley Punch to
> make the hole just slightly larger than the Copper Pipe elbows, and
> install the coil, with elbows thru the holes using the Woodstove
> Gasket Rope to make an exhaust tight fitting. Then I reroll the
> Stovepipe around the coil, and reset the Seam top to bottom. I then
> silver soldered two 3" pieces of tubing, with Copper Unions on the
> other end, to the other outside ends of the elbows, so that I could
> disconnect the water system from the Stack Coil when Service, or
> Stovepipe Cleaning (which I do annually) is required. On the other
> side Copper Unions I have Ball Valves, so I can isolate the Water
> system, without draining it, during Servicing. I usually try to place
> this section of Stovepipe as close to the stove as possible, so that
> it has access to the most BTU's in the flue.