Crispin Pemberton-Pigott

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Recent posts by Crispin Pemberton-Pigott

Greetings Julie

Your description of these designs is somewhat incomplete (and there is nothing wrong with that - I appreciate your questions as very useful).

I speak of modern versions of all devices as comparisons should be up to date when possible. Here goes:

In terms of combustion efficiency, there is very little difference between the following technologies:

Rocket Mass Heater (RMH) rooted in the work of Ianto Evans
A Masonry Heater as exemplified by the multiple works of the Masonry Heaters Association - exemplified by one of their Technical Committee members Norbert Senf and Alex Chernov https://www.stovemaster.com/html_en/gallery.html
Advanced-but-low-tech-materials biomass stoves such as the Kabuga stove, a report recently posted here:
https://www.newdawnengineering.com/website/library/Papers+Articles/CAU/CAU_FREPDC_2023
Any of a number of pellet stoves with fans (too many to show)

Combustion efficiency is a measure of how completely the fuel burns, though it is usually described in terms of combustion inefficiency because it is easier to calculate directly.  There are two versions: CO/CO2 expressed as % and CO/(CO+CO2) expressed as %, which the EPA calls the Modified Combustion Efficiency (MCE).  I am proposing a new version which is CO/(CO+CO2+CxHy) so that it covers gas appliances as well (especially propane).

For indoor cooking using a fuel like ethanol gel, the MCE should be under 2% to pass national regulation in some countries. Germany, South Africa and others.  Most small biomass burners that achieve good combustion are under 4%.  All the technologies listed above are under 0.5%.  When performance is in that range, there is no significant gain available  in terms of heat or smoke of fuel consumption - it is so clean that it becomes a numbers contest, nothing else.  Anything that can burn at an MCE of 0.2% is extremely clean. That means it is burning 99.8% of the carbon to CO2, not CO.  The unburned portion is near zero. I have seen coal stoves at 99.995% MCE.  For example here:
https://www.newdawnengineering.com/website/library/Stoves/Kyrgyzstan/KG%20Model4-Coal/

There is nothing inherent in wood that produces CO - it is manufactured in the fire. There is no performance difference between a RMH and a Masonry heater if both are properly built with one exception.  The masonry heater is more likely to have a well controlled level of excess air, compared with the RMH.  The reason for this is inherent in the design: the air entrance is not controlled, or not AS controlled.  Masonry heaters are constructed with primary and secondary air supply in a balanced manner.  The RMH (and Rocket Stoves in general) tend to have high excess air which cools the flame.  Not all the time min you, but between sometimes and usually.  The root of this is the ideology of the Rocket Stove design (originally developed by David Hancock in 1983-84, no matter what you hear on line or in blurbs) which holds that a fast, clean burn needs a lot of air.  Because the RMH at high power is very hot and clean is not a justification for having high excess air at other burning levels.  Excess air (EA) is expressed in % and refers to the amount of air present in the fire relative to the amount theoretically required for complete combustion.  The needed air supply plus 100% would give you about the cleanest burn you can get in a simple device (80-125% EA target range).  Rocket Stoves tend to be in the 600% EA range.  At low power, 2000%.  This high level of EA cools the fire and creates CO + smoke.

The claims one most often sees about any heater are not well-informed.  First they are not expressed in a manner that reflects a good understanding of what to measure and why, and they compare a product that is pretty good with something selected to be sub-standard.  If you were to look at the ISO standards for burning biomass in cooking stoves (an expensive document) they have the metrics correct: CO and PM per megajoule of energy delivered.  For example a pretty clean stove is going to emit 3 or 4 g of CO per MJ delivered to the pot.  For heaters this should be about half because heaters are more efficient at delivering heat than cookers.  When did you ever see a heater rated with CO expressed in mass/MJdelivered?  Never.  Clean burning doesn't mean efficient heating and vise versa.

EPA wood stove performance is mostly examining particulate matter (PM), not CO.  They care about smoke because all their regulatory work is based on stack testing in factories in the 70's.  The applicable standard for wood burning heaters  is CSA B415.1 : 2022, the new version being a substantially reorganized version of the confused document that previously existed.  

Enough about that.  To your specific points:

The RMH is not necessarily efficient because of the combustion efficiency.  The efficiency you refer to in that sentence is the thermal efficiency.  That is the ratio of heat delivered to the home divided by the energy theoretically available from the fuel burned.  You could burn at an MCE of 99% or 97% or 95% and still have a thermal efficiency of 75% or 80% or 85%.  They are nearly independent. The RMH has a high thermal efficiency because it has a low exhaust temperature - same as a heat-storing masonry heater - due to the long and high mass heat-collecting channels. So the "high efficiency" is not because it has a hot central column where gases are burned to completion.  If you had a similarly hot fire in any other shape but the same heat collection and exhaust temperature, the performance would be the same.   The semantic difference is that the combustion chamber and hot central passage are claimed to give good combustion efficiency, while the common term "efficiency" is intended to be the heat transfer efficiency from the hot gases to the air in the room (whether stored in high mass or not).  These two efficiencies are really independent, almost completely.  If you have a really, really bad fire, and have a really, really good heat transfer mechanism, the overall performance will be good, you just have to clean it a lot more often.  

As for the temperatures in the combustor of a masonry heater with high mass storage (5 to 8 tons of brick or rock, typically) again, these are two separate aspects.  They burn just as hot as RMHs - probably hotter due to the burn rate being higher - which delivers good combustion efficiency, and they store and deliver the heat using high mass.  That delivery is the heat transfer efficiency, not the combustion efficiency.  

Your last question hits the nail on the head.  The EU standards are for emissions per MJ of fuel energy or fuel energy delivered to the "load".  The EPA is obsessed with emissions per minute or per kg of fuel.  They are not even directly comparable. Different units.  You can assume that a kg of fuel has a certain amount of energy available, but that is not the same thing as the energy actually available.   The disadvantage American stoves have is there is a certain expectation from the public as to what constitutes a cooking and space heating wood stove.  It is a pretty big design limitation.  The masonry heaters and RMHs evade this preconception by concentrating on space heating, not cooking, though cooking is not ruled out (especially black or white ovens).  The clean burning kachelofens are simply one of the heating systems developed for burning a mass of fuel rapidly in a short time, followed by closing all doors and letting the stored heat into the room slowly.  

RMHs are not "insanely hot" although that is a great turn of phrase.  It is really hard to get a wood fire above 1200 C, and if it did, it would be a huge source of NOx pollution created by splitting N2 from the air and making a copious amount NO (thermal NOx).  There is a reason blacksmiths don't use wood.  It can be done with coal and 50% EA but not in a Rocket Stove of any kind.  Further, it is very difficult to measure the temperature of hot gases.  Personally, I do not believe any claim for a hot gas temperature unless the report includes how it was done and with what instrument.  An ordinary thermocouple grossly under-reports the actual gas temperature because it is radiating strongly.

I conclude with your last question about burning more efficiently that an RMH.  An RMH at high power can in theory have very high combustion efficiency due to the open air entrance, but not at other, lower power levels.  Don't let someone redirect combustion efficiency to thermal efficiency in mid-sentence.  Burning cleanly at all power levels HAS to include primary air control, either by a lever or clever counter-balancing airflow (buoyancy in opposing directions as is done in a Vesto).  Designing the latter requires either a lot of experience or CFD gas flow simulation as shown in the FREPDC link above (it is active in the PowerPoint, not the PDF).  A wood burning appliance can be clean and inefficient at the same time. There is a lot of room for misconceptions and error.

Stay well, burn clean
Crispin
4 months ago
The reply from Forsythe Instauratur is most relevant.  Have a read...

RMH products are considered "masonry heaters" as defined in CSA B415.1 of 2022, a recently updated standard which is accepted by the EPA, though Canada hosts the technical committee.  In Europe generally there are ways to construct new heat retaining appliances. The most important activity is in Austria where there is an officially approved spreadsheet that will calculate whether or not the design is allowed.  You can build a unique one and and don't have to have it tested for first.  There is quite a high fee for using it but it is possible.  There is an initiative by a couple of people in the Masonry Heater Association in North America (it includes Canada and the USA).  The main guy is in France actually.  He is attempting to write an accepted public domain version of the calculations so it is available to everyone.

It is true that the requirements for the EU are tighter than those in the USA, but the masonry heater guys have demonstrated repeatedly that they easily exceed all of them.  It is far easier to burn 60 lbs of wood rapidly under predictable conditions than to burn the same amount of wood at a varying rate - hence the heat storage.

At present Canada/USA do not accept predictive models of performance.  Build, test, approve, disseminate.  Fireplaces and masonry heaters are not regulated at present, neither are coal stoves. However anything burning biomass is covered in B415.1 with at least a test method and suitable metrics.  Only some products have requirements.  It also covers stoves with TEGs for electricity.

I see a comment that RMHs are not allowed in Europe because the fire is open to the room.  I have not seen that reason given specifically for any country.  It is possible but there are ways to provide air and an enclosing portal for fuel so it is not a universal objection.  A door over the fuel hole with adequate air holes is not different from a fireplace with a door and vents.  What matters (a lot) is draft and various points where minima apply.  

I understand that the relevant European standard is EN 15250 "Slow heat release appliances fired by solid fuel. Requirements and test methods".   A copy might be available from www.kamicenter.ru/content/news/index.php? ELEMENT_ID=672

Kami Center is the effort on one man Mr Batsulin and he has done an amazing job of training and certifying many builders of masonry heaters.  He has been working based on the old USSR Standard GOST 3000-45 "Heat capacious heaters, methods of testing."  The "G" means it is a national standard'.  Same as China.  Warning, the legal construction method of a brick chimney passing through the second (wooden) floor of a house has been updated to widen it a little.

RHM:  It would be necessary to add a bleeder to the top of the heat exchanger leading to the chimney to prevent CO being trapped there.  I have used this routinely on downdrafting heat exchangers, for example on the Kyrgyzstan KG4 and KG5 series of heaters.  There is a German word that I can't remember for this deliberate "leak" up to the chimney.  This can guarantee the chimney draft is adequate even if the heat exchanger has over-extracted heat and created a dangerous situation (such as a gust of wind reversing the chimney).

Stoves with a safe downdrafting heat exchanger:
https://www.newdawnengineering.com/website/library/Stoves/Kyrgyzstan/KG%20Model4-Coal/KG4.4.12%20Updated%2016%20Dec%202017/ Go back one folder to see other models.
Polish copy, water heating version: https://www.zebiec.pl/kotly-co/szafir-kociol-na-wegiel/?lang=en
Document on the development of this culturally relevant stove (you have to click on "Download") https://openknowledge.worldbank.org/handle/10986/31282

It may be a challenge in Europe to build a heater that has any portion of the gas path with a positive pressure channel made of clay.  

Serious technical questions? Contact me.

Burn 'em clean...

Crispin

Member: TSC, CSA JB121.1
ISO TC-285
CSA JB127 for ISO-238
SABS TC-1054
New Dawn Engineering Inc, Alberta
5 months ago
There are a selection of hand operated chain link machines on the web in www.newdawnengineering.com

Look are the half-pipe channel that accepts the piece being made and the pins that hold the previous one.

There are downloadable instructions and a section on costing.

There is a completely different method of hand making the same product I have seen in Africa. Essentially you wind a wire around a short flat plate with the width matching the diagonal of the diamond. Then the flat coil is pulled off and stretched to take the shape of a "piece". These are hand wound into the end of the roll being assembled.

If someone wants to manufacture the New Dawn Eng design, contact me.

Crispin Pemberton-Pigott
10 months ago
There is a white glue that comes with the replacement door seal .  It hardens really well.

Pour some into the open space to wet the seal and press it down with a flat stick so it is sealed again.  

The glue will dry and make it air tight.  Check the inside at that point to see how it looks.

If there is a bend in the door, opening a small gap for a significant part of its length, don't despair.  Replace the whole seal again and press it shut to let the glue set.  Presto.

Cheap and easy.

Don't try to bend the metal back. Not worth all the risks.  

This "cure" might glue the glass to the metal frame at that point.  It will still expand a little from heat.  Therefore it is not suggested you make a similar repair on the other side(s).  Better to re-seat the glass with a new seal and glue.  A new seal is much puffier than an old one so it seals all gaps.
1 year ago
This is the general case installation guide (not showing the particulars of the passage through a floor or ceiling).

Crispin
2 years ago
I have an update on the chimney termination above the roofline.  

I wrote that I would find the installation manual for Kyrgyzstan which cites the updated Russian national building code (I think 2016 or so).  

It is not "one rule for all".   Please see the attached schematic.

+++++++++++++
Within 1.5m of the ridge, it should be 0.5m above the ridge.
Within 3m of the ridge, same level as the ridge.
More than 3m from the ridge, at a line descending 10 degrees from the ridge.
+++++++++++++

Of course there is no problem to be higher than any of these values.

Crispin
2 years ago
Greetings

I confess at the beginning I am a stove designer.

The leak between the chimney sections when you "do anything" is a key indicator that you have positive pressure inside the upper chimney created by the local environment and positive pressure at the bottom created by the buoyancy of the hot exhaust.  Otherwise the leak would not occur. The pressure inside the chimney would should always be negative compared with the room(s).

Key to solving this will be addressing what is going on at the top of the chimney. Wind can easily blow air down a chimney for all the reasons mentioned by others.  

I was surprised by the chatter about vane hoods being a problem re durability. These draft inducers are common enough around the world. The rotating (spinning) type are very reliable so why would a swinging one be a problem?

Various static induction or more correctly "eduction" designs have been made going back centuries.

Let's concentrate on your upper installation. It sounds as if everything is fine, but you have positive pressure inside the stack which should not be the case.

In the Russian national standard, they have a different approach to the eternal dimension spec. The 10 feet rule is not applied in the building code. The rule is: take the top of the peak and draw a line at ten degrees down towards the chimney. The stack exit must be above that line. I can't remember if it is one foot above but certainly it must not be below it.

We used that standard when creating an installation manual in Kyrgyzstan and never had draft problems with stoves that were much more efficient than the usual crap. More efficient usually means with a lower gas exit temperate (but not always). So less draft available, but no trouble.

These installation specs are in the building code, not the stove performance standard such as CSA B415.1 which applies in Canada and the USA. (A new update is coming in a couple of months, BTW.)

Explore the 10 degree clearance idea, and see if your chimney would pass the standard applied in most of Eastern Europe and Central Asia.

Second, temporarily remove whatever cap you have to see if it is responsible for creating positive pressure at the top. Maybe it's fine. I haven't used that draft-creating cap in the photo before, but it looks interesting. It has no moving parts. If it doesn't work, send it back for a refund.

Third, regarding the make-up air - try opening various upstairs windows instead of the nearby door. Windward side, leedward side, find out what doesn't work. Ruling things out is as important as finding conditions that work. If it suddenly solves the problem it points to an architecture problem (building layout etc).

Fourth, the comment about trees might be significant. I don't thinl you have a stove problem. You have an architecture problem. If it was me, I'd immediately put on a swinging vaned hood while seeking other solutions.

Fifth, if you raise the top of the chimney, check with the rules about the support and the "vee" of sheet metal that diverts snow around it. It should be able to pass a WETT inspection even if your municipality or insurance company doesn't require it.

Lastly, Permies readers can reach me using crispinpigott at outlook dot com. I can dig out the graphics on the chimney top dimensions and slope.  It might be on my website at www.newdawnengineering.com in the library, stoves, Kyrgyzstan. There is an English version somewhere.

Stay well
Crispin
2 years ago
Apologies if this posted twice.

Ted:

Unfortunately there is quite a bit of misdirection in the replies below and not wanting to offend anyone I will try to give you some guidance in principle and for your application.  Please everyone, tolerate my alternative interpretations as just that.

>I remember somebody saying that if you close up a chimney with a baffle that is just a metal plate that closes over it, that it would be friction and slow down the fire.

This is correct, such a device is called a chimney damper for the reason that you "dampen the fire" in the sense of slowing down the burn rate. A damper is quite permissible provided that it is not able to close off the chimney completely. There are often regulations about this where the area can be reduced by 2/3 leaving 1/3 open when fully closed.   This is essential for late fire emissions to escape.  Most stoves (including rocket mass heaters) have poor combustion in the late fire due to high excess air (far too much air for the fire's requirement) and poor control over it.  

Mostly, it is not a good way to control a fire's burn rate. In all cases possible, the system should be constructed so as to limit the ingress of air, not the egress of gases. When the entrance is limited, and the chimney is pulling, any leaks permit air to enter the stove, whereas in the opposite case the gases inside try to leak out.  A negative draft maintained on the top of a fire should be about 20 pascals if you can arrange it.  That is very little, but it means a warm chimney pulling and air entering the stove through the controller with the entrance as the restriction on the system.

CO leaking out of the stove into the room is not heavier than air. CO2 (44 mole mass) is and sinks, but not CO. CO is almost exactly the same density as air (28 mole mass) and disperses very effectively throughout the room causing problems. The mechanism is it displaces oxygen on the red blood cells so it lowers the oxygen carrying capacity of the blood.

>Does a hose nozzle work as a venturi or a restriction?  

Anything that reduces the flow up a chimney will reduce the exhaust gas flow rate.  The temperature of the chimney above and below the restriction will change if you change the amount of that restriction.  This will affect the total draft on the stove. Generally speaking, all stoves in the USA have exhausts that are too large in diameter to work properly, the chimneys are too large in cross-section, and the exit temperature is too low to be effective.  That is a pretty broad condemnation, but it is just how it is.   Most stoves require a barometric draft regulator but do no get it. If the chimney is hot enough to work properly it tends to generate thermal runaway: more heat leads to more firepower leads to more heat in the chimney leads to more firepower.  That is not how most people want their devices to operate.

Draft in a chimney is a source of "power".  You could use a fan, but a warm chimney is capable of "doing work".  So a chimney is really a natural fan.  The power available can be directed in various ways: You could turn the energy into a "suction" on the fire and the air entrance (the preferred option). You could dissipate the energy creating a high velocity flow gases past the restrictive plate you are considering, slowing down the total flow.  Given any constant temperature in the chimney, the available energy could pull a lot more air quickly, or more slowly but having a high flow rate past the restriction point.  You may have a reason for wanting that.  You could use a small diameter chimney so the energy was dissipated along the whole pipe length limiting the flow to a certain desirable rate.  Usually that is a good idea.  The main point is there is energy available and you can choose were it is applied.  It might be at the secondary air entrance adding velocity (one of my favourite design ideas.)

Now for your main motivation:

>...also at the same time be a restriction that would allow soot to burn up completely (actually in a restriction that speeds it up, soot particles should shrink just on that).  

What you describe is a fire that is not burning cleanly, followed by some attempt to fiddle with the flow rate of the gases in order to reduce the smoke generated.  It is already too late. If the fire is not burning cleanly in the first place, it is far better to burn better than to try to clean up what should not be there. Slowing down the gas flow rate in the chimney is very unlikely to correct a bad combustor design.  That is not how things work.  Poor combustion has several classic causes so addressing them is a better approach.

>...but really burn up those soot particles and shrinking them too

Smoke particles don't "shrink".  They grow, rapidly.  You are quite correct that they are combustible. Smoke is almost entirely made up of unburned fuel and water vapour. A small amount of a typical stove's emissions is ash, not the products of incomplete combustion. Creating good operating conditions for combusting biomass requires meeting certain conditions.

One is an oxygen level of about 8% to 10% in the exhaust.  This is air which is not required to burn the fire.  Biomass is not as easy to burn as gaseous fuels which can tolerate very low excess air levels (even 1% or less O2). If you have 18% O2 in the exhaust, that is 600% excess air and it FAR too much to burn cleanly.  

The calculation is:  Measured Oxygen %/(21% minus measured Oxygen %)  The answer is the excess air factor, so multiple by 100 to get %.  
Note that it is not the total air demand, which is Excess air + 100% also called "Lambda".

All that unwanted excess air cools the combustion.  Slowing down the exhaust does not guarantee the O2 level will drop. It might, it might not.  It depends on the architecture of the stove.  But one thing for sure, it should not be more than 10% when running on high power. If you have a technically sophisticated burner, you can get it down to 6% but that is not for the ordinary hacker. Instrumentation is required.

You are correct that if you burn the smoke it will yield more heat.  However burning the CO gives far more heat than burning the smoke. C to CO yields about 8 MJ per kg of fuel. CO to CO2 gives more than 24 MJ/kg.  So if you lose a lot of energy to CO (bad combustion), you can get it back by burning the CO instead of carefully venting it outside. Emitted CO is a called a "chemical loss".

To keep CO burning needs about 820 C above the combustion zone. This is NOT provided by blowing harder on the air supply, which will just force more cold air though the chamber, cooling the fire. Blowing on a charcoal or coke fire like a blacksmith usually create a lot more heat, but huge amounts of CO.  Such a fire is not a good example of clean combustion at all.  Hot, yes, but not clean.

To get a clean, hot burn, your fuel load should match the grate area and a lot of other things.  Most stoves have:

too large a grate
too large a fire chamber for the typical fuel load
too much primary air
too large a chimney diameter
too little insulation around the combustion zone to maintain a hot fire needed to light the CO produced
too low an operating temperature
too little draft or
Too much draft without a barometric draft regulator

Putting an air control at the air entrance is how to control the fire intensity.
Secondary air (if supplied) should be approximately twice the primary air supply and where possible, preheated. If you want to burn wet wood, the primary air has to be preheated (big emissions reduction).

Most stoves have far too much primary air so any secondary air is just a waste of energy as the air goes in, is not used or needed, and carries heat up the chimney.

Very clean burns can be obtained without any grate - see Masonry Heaters available from the Masonry Heater's Association website. If the floor of the chamber is made from firebrick, effective combustion can be maintained for a long time. Recent developments in combustion include placing a layer of small stoves (20-30mm) over the whole fuel bed (still no grate).  This may not suit people burning 24/7 however, try it and see the difference.  It reduces smoke generation a lot in some cases.

Very high performance stoves (called HELE for high efficiency low emissions) have a surprisingly low chimney gas velocity of 150 to 250mm per second in a chimney that is about 1 square inch (6.5 cm^2) per kW of firepower. When you compare that with what is usually provided or "required" you may be surprised.

General rules are: burn first, clean and hot.  Then transfer heat to some surface, then vent what is needed to operate the chimney properly. Do not use a chimney as a heat exchanger save for the first few feet.  Once heat enters the chimney, keep it there to operate the draft into the stove properly. You gain nothing from a warm chimney after it departs the heated envelope, i.e. above the ceiling.

Good luck with your investigations. Modern HELE stoves can be see (drawings and all) in the Library of www.newdawnengineering.com under Library / Stoves, then by country.  One you might check out is the KG2.5 under Kyrgyzstan.  Have a look at the function of the "flame tube" which burns smoke and CO as it enters the heat exchanger. It is so effective that the top of the heat exchanger serves as a third cooking position.  The Kyrgyzstan project is quite interesting. You can read about the development of the main stoves here:

https://openknowledge.worldbank.org/handle/10986/31282
(click the download button)

A precis is available at https://openknowledge.worldbank.org/bitstream/handle/10986/31774/Beyond-the-Last-Mile-Piloting-High-Efficiency-Low-Emissions-Heating-Technologies-in-Central-Asia.pdf

And the dramatic impact it produced on people here:

https://www.nature.com/articles/s41533-019-0144-8.epdf

Stay well.
Crispin
4 years ago
The stove is indeed a coal stove, though that is not the only model we used. Altogether 4 different stoves were developed, initially in Tajikistan, of which 2 were specifically for biomass in any form (dung is a very important fuel at high altitude).  Now there are 6.  There had never been a stove in Central Asia before which could burn dung without the addition of some sticks and wood.  The oft-assumed unburnability of dung was shown to be incorrect. It can be used to heat a home at -30C and cook properly, if operated in a new manner (back lighting) and if there is a "flame tube" incorporated into the heat exchanger.

It was decided to report the KG4 series in this document because it highlighted that if a concerted effort was made to apply modern engineering, assessment and testing, it was possible to produce a coal burning stove that was about as clean as propane. We won't quibble about numbers, it is just important to show that profoundly clean coal combustion is possible and that people dependent on it should not be denied access to modern engineered solution. In short, a pro-poor policy of doing what we can with what they have, given that nothing else will be done that helps them. We are also attaching the false claim that all solid fuels are "inherently dirty" - a position promoted by those advocating gas and liquid fuels. It's nonsense.

Touring the Kyrgyz uplands last year in February was shocking in some ways. People are so poor it is tragic, and they have terrible living conditions because of the poor stove designs and condition. Everyone over 40 is said by the Chief pulmonologist to have COPD. Everyone with one of these KG4.3 stoves was so-o-o happy. In most cases the stove saved more fuel expenses than they received per month from government in welfare payments.  The stove saves enough fuel to pay for itself after 4 months. So the issue is access, not affordability. All the designs and drawings are available at my website (in the public domain) www.newdawnengineering.com in the Library/Stoves/Kyrgyzstan then folder KG4.3 or 4.4 (there is a small difference in the overall length of those two versions).

In principle, the same combustion system (cross draft gasification) could be used to burn wood but we are not there yet.
5 years ago
This needs a new Forum category: Domestic space heating and cooking.

There is a new technical paper in the World Bank’s Open Knowledge Repository:

“World Bank Group. 2019. Advancing Heating Services Beyond the Last Mile : Central Asia Pilot Experience with High-Efficiency, Low-Emissions Heating Technologies. ESMAP Paper; World Bank, Washington, DC. © World Bank.

Please ask readers to download a copy from the website as it counts the number, and that ultimately influence pro-poor policies.  This paper on HELE stoves is downloadable from the following webpage:
https://openknowledge.worldbank.org/handle/10986/31282 or http://hdl.handle.net/10986/31282

Please share the link widely.

The direct link to the PDF is
https://openknowledge.worldbank.org/bitstream/handle/10986/31282/134620-WBAHSWEB.pdf?sequence=1&isAllowed=y

The document provides a detailed description of how one of the cooking and heating stove technologies used in the Kyrgyzstan Winter Heating Pilot was developed.  It is a comprehensive discussion of the social and technical factors that contributed to the success of this Pilot, producing significant impacts on health, income and comfort of people living “beyond the last mile”. A link is provided to the full set of drawings and some photos archived in the ESMAP Library.

The point of saying “beyond the last mile” is that whatever are the current plans to extend modern heating and cooking services, there are a large number of people who will not be reached. This group of 500m people “beyond” are, now and in the medium term, dependent on burning solid fuels (biomass, dung and coal).  The question addressed is: What can we do for this group of low income, deeply rural and hardly accessible families which suffer all the negative consequences of chronic cold, poor combustion, indoor leakage of smoke, inconvenient drudgery and a dire lack of access to modern energy?  How can we bring modern science and engineering to these spatially and culturally diverse groups?  

The article proposes a comprehensive approach and describes how this was done in highland, rural areas of Kyrgyzstan. It covers in some detail how the KG4.3 crossdraft stove was developed over 9 years and the scientific cooperation between groups in several countries that led to the development of this HELE technology.

This document can be used to inform policy in multiple ways. If we are to eventually bring modern energy services to everyone, which will take time, there are highly beneficial interventions which can be made a low cost per person, even in poorly served regions using carefully crafted technology transfers. Apart from all the social and health benefits, the project also makes positive impacts on everything from local employment, the social status of women, emissions of CO2, Black Carbon and PM2.5.

Two further papers reporting the health benefits of the project have been submitted by the Dutch International Primary Care Respiratory Group to the WHO Bulletin and npjPCRM (Primary Care Respiratory Medicine) which conducted a Fresh Air-sponsored study of the impacts of the stove and low pressure boiler replacements.

Please circulate the links given above to anyone who you think is interested in these topics.  Stove designers will find a good deal of technical information about construction and principles of combustor operation, as well as guidance on how to interact with the communities in which it is intended to provide such modern heating and cooking services.  This crossdraft technology has already been replicated in China, Kyrgyzstan, Mongolia, Russia, Poland, South Africa and Tajikistan. A few photos are provided.

Forthcoming: Complete details on construction of three versions of the technology will be included in the final report from the World Bank-funded UB-CAP Project in Ulaanbaatar, Contract C-5039-MN/KLTA-01.

Best regards
Crispin
5 years ago