Post by pioniers on Dec 23, 2013 6:01:27 GMT -8
Hello
I am building now rocket mass heaters (RMH) for 7 years. In these RMH’s I am using the firebox as developed by Peter van den Berg for the last 2 years, because of its good combustion properties. For this firebox I am now developing a new way of secondary air injection, which will replace the so called P-channel in the current design. Because things need a name I will call this new development the S-portal.
Being a professional masonry heater builder, I put intellectual property rights on the S-portal, it is not freely available for commercial use. Please contact me if you have plans to do so. It is however freely available for anyone who wants to use it to build a RMH him or herself. The rocket stove concept is growing due to the open source mindset behind it, and I like to contribute in this way to it.
For more information have a look at : www.rocketstove.nl
Feel free to contact me if you have plans to build a batch rocket with a S-portal yourself
Sjang van Daal
Secondary Air modification for batch rocket mass heater.
I have been building rocket mass heaters (RMH) for the past 7 years. In these RMH’s I am using the firebox as developed by Peter van den Berg for the last 1 1/2 years, because of its good combustion properties. For this firebox I am now developing a new way of secondary air injection, which will replace the so called P-channel in the current design. Because things need a name I will call this new development the S-portal.
Being a professional masonry heater builder, I put intellectual property rights on the S-portal, it is not freely available for commercial use. Please contact me if you have plans to do so. It is however freely available for anyone who wants to use it to build an RMH him or herself. The rocket stove concept is growing due to the open source mindset behind it, and I like to contribute in this way to it.
What is an S-portal?
The S-Portal is a stone or steel frame around the exit to the heatriser. The frame is hollow and fresh air, entering into the frame from outside the firebox, is injected through slits in the frame into the flames and smoke gasses. The S-portal can have any shape and is positioned vertically in one of the sidewalls of the firebox.
Below a few examples of the S-Portal are displayed:
How it works
Good combustion needs secondary air. Currently secondary air is brought by the P-channel at the top of the gate to the heatriser. See also in the figure below. The second figure below is the situation with the S-portal.
(Red= flames/smoke gasses, Blue= secondary air).
Cross-section of RMH with P-channel
Cross-section of RMH with S-Portal
The principle behind it is easy to understand, when you bring small amounts of well preheated secondary air all around into the smokegasses, you will get good combustion more easily.
Advantages S-portal
There are a number of proven and/or expected advantages:
1. Lower excess air ratio, stability in the burning process is measured as low as lambda = 1,07
2. Higher efficiency. Lower excess air ratio will give a higher combustion efficiency, see below for a sample of the flue gas analysis.
3. Cleaner combustion with lower emissions of CO, PAC’s etc., see also below for a sample of the flue gas analysis.
The S-Portal will give a better combustion at lower draft levels in the chimney, which is an important advantage in masonry heaters.
4. The S-portal air inlet can be combined with the primary air inlet and is time and cost saving in the construction of the masonry heater. For this purpose the S-portal is mounted on a steel plate which is extending forward through the firebox, functioning as the floor. At the front of the stove below the steel plate there's the secondary air inlet and above it the primary air inlet.
5. Safety: With the P-channel air inlet positioned above the firechamber there is a chance, very small, that in case of a blockage in the system smoke will enter the room via the P-channel. Even in case of a total blockage of the system a RMH with an S-portal will extinguish itself because both air inlets are below the fire chamber.
Here are diagrams of the flue gas analisis:
The first one is taken from a test run using the S-portal, the second from a test run using a P-channel. Mark the significant differences in O² and CO levels.
O2= Oxygen, n= efficiency, CO= Carbon monoxide,
Tr= Temperature chimney
O2= Oxygen, n= efficiency, CO= Carbon monoxide,
Tr= Temperature chimney
Thanks Peter (van den Berg) for the nice testing day we had and bringing your Testo 330 for the nice graphs.
I have a Testo 327, which is nice to give you basic information, but for serious testing I strongly recommend the 330.
Dimensions and proportions
For people interested to build a RMH with an S-portal, below there's a summary of important dimensions. These are not final at all, it can take months or longer before we can be sure about these. I try to stick as much as possible to the standard Peter tries to establish for the batch rocket.
Standard for the P-channel RMH:
Primary air is 20% of the area of the heat riser
Secondary air is 5 % of the area of the heat riser
Concept Standard for the S-portal RMH:
Primary: +/- 12%
Secondary: +/- 10 %
Practically this works out as follows:
Gate from fire chamber to heat riser
(with base parameter B= 72% of diameter heat riser)
Gate width: 0,5 B , Height: 2,2 B
Applied to 150 mm system 6”:
Gate is 5,5 by 23 cm
S-portal tubes: 3 by 4 cm outside, inside 2.6 by 3.6 cm
Slit in the beam: 20 cm by 4 mm, start 2 cm from the bottom
Applied to 180 mm system (+/- 7” system)
Gate is 6,5 by 28,5 cm
S-portal tubes: 4 by 4 cm outside, inside 3.6 by 3.6 cm
Slit in the beam: 25 cm by 4.5 mm, start 2 cm from the bottom
In the 150 and 180 test systems I built I used normal mild steel tubes, which seems to hold in this inferno, thanks to the air that’s cooling it from the inside.
Pictures:
180 mm test bed system, chimney loops back to cool down gasses.
Firechamber with S-portal
S-portal with slits cut with grinder
Test bed system in full operation with the S-portal visible in the rear wall
As usual, these rockets are heat machines, through the riser tube and the ceramic blanket it does shine like a lampoon.
I am building now rocket mass heaters (RMH) for 7 years. In these RMH’s I am using the firebox as developed by Peter van den Berg for the last 2 years, because of its good combustion properties. For this firebox I am now developing a new way of secondary air injection, which will replace the so called P-channel in the current design. Because things need a name I will call this new development the S-portal.
Being a professional masonry heater builder, I put intellectual property rights on the S-portal, it is not freely available for commercial use. Please contact me if you have plans to do so. It is however freely available for anyone who wants to use it to build a RMH him or herself. The rocket stove concept is growing due to the open source mindset behind it, and I like to contribute in this way to it.
For more information have a look at : www.rocketstove.nl
Feel free to contact me if you have plans to build a batch rocket with a S-portal yourself
Sjang van Daal
Secondary Air modification for batch rocket mass heater.
I have been building rocket mass heaters (RMH) for the past 7 years. In these RMH’s I am using the firebox as developed by Peter van den Berg for the last 1 1/2 years, because of its good combustion properties. For this firebox I am now developing a new way of secondary air injection, which will replace the so called P-channel in the current design. Because things need a name I will call this new development the S-portal.
Being a professional masonry heater builder, I put intellectual property rights on the S-portal, it is not freely available for commercial use. Please contact me if you have plans to do so. It is however freely available for anyone who wants to use it to build an RMH him or herself. The rocket stove concept is growing due to the open source mindset behind it, and I like to contribute in this way to it.
What is an S-portal?
The S-Portal is a stone or steel frame around the exit to the heatriser. The frame is hollow and fresh air, entering into the frame from outside the firebox, is injected through slits in the frame into the flames and smoke gasses. The S-portal can have any shape and is positioned vertically in one of the sidewalls of the firebox.
Below a few examples of the S-Portal are displayed:
How it works
Good combustion needs secondary air. Currently secondary air is brought by the P-channel at the top of the gate to the heatriser. See also in the figure below. The second figure below is the situation with the S-portal.
(Red= flames/smoke gasses, Blue= secondary air).
Cross-section of RMH with P-channel
Cross-section of RMH with S-Portal
The principle behind it is easy to understand, when you bring small amounts of well preheated secondary air all around into the smokegasses, you will get good combustion more easily.
Advantages S-portal
There are a number of proven and/or expected advantages:
1. Lower excess air ratio, stability in the burning process is measured as low as lambda = 1,07
2. Higher efficiency. Lower excess air ratio will give a higher combustion efficiency, see below for a sample of the flue gas analysis.
3. Cleaner combustion with lower emissions of CO, PAC’s etc., see also below for a sample of the flue gas analysis.
The S-Portal will give a better combustion at lower draft levels in the chimney, which is an important advantage in masonry heaters.
4. The S-portal air inlet can be combined with the primary air inlet and is time and cost saving in the construction of the masonry heater. For this purpose the S-portal is mounted on a steel plate which is extending forward through the firebox, functioning as the floor. At the front of the stove below the steel plate there's the secondary air inlet and above it the primary air inlet.
5. Safety: With the P-channel air inlet positioned above the firechamber there is a chance, very small, that in case of a blockage in the system smoke will enter the room via the P-channel. Even in case of a total blockage of the system a RMH with an S-portal will extinguish itself because both air inlets are below the fire chamber.
Here are diagrams of the flue gas analisis:
The first one is taken from a test run using the S-portal, the second from a test run using a P-channel. Mark the significant differences in O² and CO levels.
O2= Oxygen, n= efficiency, CO= Carbon monoxide,
Tr= Temperature chimney
O2= Oxygen, n= efficiency, CO= Carbon monoxide,
Tr= Temperature chimney
Thanks Peter (van den Berg) for the nice testing day we had and bringing your Testo 330 for the nice graphs.
I have a Testo 327, which is nice to give you basic information, but for serious testing I strongly recommend the 330.
Dimensions and proportions
For people interested to build a RMH with an S-portal, below there's a summary of important dimensions. These are not final at all, it can take months or longer before we can be sure about these. I try to stick as much as possible to the standard Peter tries to establish for the batch rocket.
Standard for the P-channel RMH:
Primary air is 20% of the area of the heat riser
Secondary air is 5 % of the area of the heat riser
Concept Standard for the S-portal RMH:
Primary: +/- 12%
Secondary: +/- 10 %
Practically this works out as follows:
Gate from fire chamber to heat riser
(with base parameter B= 72% of diameter heat riser)
Gate width: 0,5 B , Height: 2,2 B
Applied to 150 mm system 6”:
Gate is 5,5 by 23 cm
S-portal tubes: 3 by 4 cm outside, inside 2.6 by 3.6 cm
Slit in the beam: 20 cm by 4 mm, start 2 cm from the bottom
Applied to 180 mm system (+/- 7” system)
Gate is 6,5 by 28,5 cm
S-portal tubes: 4 by 4 cm outside, inside 3.6 by 3.6 cm
Slit in the beam: 25 cm by 4.5 mm, start 2 cm from the bottom
In the 150 and 180 test systems I built I used normal mild steel tubes, which seems to hold in this inferno, thanks to the air that’s cooling it from the inside.
Pictures:
180 mm test bed system, chimney loops back to cool down gasses.
Firechamber with S-portal
S-portal with slits cut with grinder
Test bed system in full operation with the S-portal visible in the rear wall
As usual, these rockets are heat machines, through the riser tube and the ceramic blanket it does shine like a lampoon.
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