Biomass Stove Design

Effective cooking stoves share some key design principles. Here we hope to share those with you. Let us know if you find areas we have missed.

Use the design menu to narrow the list of stories to the topic specific to your interest and application.

Principles

  • GIZ HERA cooking energy compendium

    Christa Roth, January, 2012

    To the members of the list who don't know Energypedia yet: it is an online resource created as a Wiki by GIZ . After some years of development as company-interal resource, it was opened to the public energy community late last year. No registration needed to read.

  • TLUD Workshop in Seattle Friday Jan 27 9am-1pm before ETHOS

    TLUD Workshop being offered prior to ETHOS Conference
    Hosted by Hydrovolts

  • Dr. Reddy - Understanding Stoves

    Dr. N. Sai Bhaskar Reddy, CEO, GEO December, 2011
    http://e-geo.org

    See the attached pdf (about 150kb): Understanding Stoves
    it is an excellent brief summary that highlights the important aspects of stoves design and testing. e.g. fuels, fuel preparation, stove design, materials, use and testing.

  • GIZ HERA new publications

    Christa Roth, February, 2011

    Dear all, find below the links to new publications by GIZ HERA poverty-oriented basic energy services, among them the manual on Micro-gasification: Cooking with gas from biomass. For queries please refer to the respective authors or Michael Blunck from HERA.

    the HERA web site

    Micro-gasification: Cooking with gas from biomass
    http://www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf
    Micro-gasifiers: much more than „just another improved cook stove”. In this new HERA handbook, Christa Roth provides an introduction to the concept and the application of wood-gas burning technologies for cooking.

    Modern Energy Services for Modern Agriculture. A Review for Smallholder Farming in Developing Countries.
    http://www.gtz.de/de/dokumente/giz2011-en-energy-services-for-modern-agr...
    This publication provides an overview on energy inputs required in different steps of the agricultural production chain, such as production, post-harvest and storage, processing, and commercialization.

    Small-scale Electricity Generation from Biomass – Part III: Vegetable Oil
    http://www.gtz.de/de/dokumente/giz2011-en-small-scale-electricity-genera...
    In the third and final part of HERA’s paper series on power generation from biomass, GIZ and non-GIZ experience with electricity production from vegetable oils is compiled. While from a technology point-of-view, plant oils constitute a very viable option for off-grid power generation in developing countries, their sustainable application in daily operation for rural electrification projects still remains rare. The paper identifies remaining bottlenecks and provides recommendations for future electrification projects based on plant oil.

    Carbon Markets for Improved Cooking Stoves – Revised Edition: January 2011
    http://www.gtz.de/de/dokumente/giz2011-en-carbon-markets-for-improved-st...
    After receiving a lot of positive feedback for the 2010 edition of the carbon market guidebook for cooking stove projects, HERA has come up with a major revision for 2011. Besides a large number of minor corrections and updates, a new chapter on “Implementing a Carbon-funded Cooking Stove Project” with information on how to practically design a carbon-funded stove project has been added. The chapter includes information on stakeholders’ roles and responsibilities, the CDM-PoA approach, recommendations on the use of carbon revenues as well as an overview on expected costs and revenues from a stove project on the carbon market.

  • CERAMIC DEVELOPMENT FOR DOMESTIC STOVES 
    Crispin Pemberton‐Pigott October, 2008 Sustainable Energy Technology and Research Centre University of Johannesbrg  Programme for Basic Energy Conservation GTZ/ProBEC a SADC Regional Project  See the attached pdf: CERAMIC DEVELOPMENT FOR DOMESTIC STOVES  Also take a look at Crispin's very good ceramic stove image galleries. It is intended that this brief report describe in an accessible manner the results of some basic research into the performance of ceramic materials suitable for use to make modern, low‐cost improved charcoal stoves. The  theatre of investigation is the area around Maputo, Moçambique.   The information and ideas are assembled from a large number of tests and reports. If studied carefully an understanding can be gained of the  principle ingredients found in typical clays. It is hoped enough can also  be learned about what the tests show so as to interest the ‘stover’ in a  deeper study of this vast subject.   Some reasons why clay stoves and stove components typically have such a  short life are described and to a certain extent, what can be done about  it.    There is a great deal of material available on how to find, identify and  process clays such as pottery books and the internet. It is not repeated  here.  Unfortunately very little of the material available is geared to  the design of low cost ceramics stoves which have problems not encountered  in many industrial applications with far higher temperatures.   Ceramics are complex mixtures of many minerals so it is not possible to  give comprehensive explanations in such a brief text, however the novice  reader should learn enough to be able to deal with a laboratory and  understand some common terminology and the test results.  There have been  many technological advances in recent years making accessible tests and  analyses that were previously unaffordable to the ordinary potter.
  • Woodstove Compendium: Available online!

    On Appropedia.org

  • Stoves Design and Principles

    The stoves design and principles are explained with simple sketchs. Many stove designs are existing, but most common designs are presented here.

    Stoves evolution reddy geo ver1

  • Observations: Design Principles for Charcoal Stoves
    Christa Roth and Christoph Messinger, August 2010 Existing Charcoal Stove Existing Charcoal StoveImproved Charcoal Stove Improved Charcoal Stove Improving the Charcoal Stove for Haiti, Stove Camp 2010 (see the Stove Camp Summary for challenge details) Main points mentioned at the end of the Stove Camp Workshop
    1. We need a high turn down ratio.

      To bring water and foods fast to the boil, we need high power in the heat-up phase. However, thereafter we commonly need low power for simmering. The stove therefore needs to offer the opportunity to turn down the power output drastically. Options:

      1. Regulation of primary air supply (e.g. closing door)
      2. The gap between pot and charcoal is increasing over cooking time (shape of char container provides more depth = increased gap to the char)
      3. c) The amount of char available at the end of cooking is reducing (conical shape of char container = less char over time available)
    2. We need to reduce heat losses to the bottom and to the side of the stove.

      A char container radiates heat to all sides – not just to the pot. To reduce the amount of char used, it is important to reduce the heat losses to the other directions. Options:

      1. Bottom of stove: rebounding plate (with holes) in between primary air supply
      2. intake and charcoal container. Thus primary air is channeled through the
      3. heated rebounding plate, taking some heat back into the char container.
      4. Side of the stove: double wall with air in between for insulation.
    3. We need to maximize heat harvest from a given amount of charcoal.

      Charcoal burning is mainly influenced by the amount of air available in the char container. Options:

      1. A vertical spacer in the center of the charcoal container (Lanny Henson’s pig tail”) seemed to increase the availability of air for charcoal combustion.
      2. Additional draft (e.g. forced air) may increase heat generation per time unit. However, this may also increase CO emissions and reduce efficiency of char use.
      3. Secondary air to burn off the CO in a gap between the charcoal and the pot may provide additional heat. However, for this to be beneficial it may not impact on the surface area available for direct radiation from the charcoal to the pot and should not cool down the air in the gap (well preheated secondary air).
    4. We need to maximise heat transfer to the pot.

      Generating as much heat as possible out of a given amount of charcoal is one step. But another important step is to make sure that most of this heat actually is transferred into the cooking pot. Options:

      1. “Sunken pot” concept seems to provide best results in terms of heat transfer (Henson stove). Unfortunately, in real life this might not be possible in many work environments.
      2. Best heat transfer is NOT achieved if the pot rests on the char. Optimum is about 1inch away from the char, not closer than that. For Simmer, this could increase to 2-3 inches.
      3. A skirt is highly important to shield the gap area between the pot and the char against the influence of wind. The gap between pot and skirt should bedetermined.

    Christa’s Summary of the stove camp

    Observation and necessary actionDerived Design Principles
    Charcoal radiates heat to all sides: as much can radiate towards the bottom of the stoves as can radiate upwards towards the pot. Action: Avoid loss of radiating and conducting heat from charcoal that is not directed towards the pot.
    • Add space between the charcoal grate and other stove parts: Lift the charcoal grate slightly off the bottom of the stove and increase the space to the sides of the stove.
    • Limit the places where the hot grate can conduct heat to other stove parts.
    • Add a deflector plate between charcoal chamber and the stove bottom to radiate heat back upwards.
    • Insulate the stove bottom to prevent heat loss through the bottom.
    • Insulate sides of the stove.
    • Regain heat through air circulation (air cooling of stove) by passing air through heated stove parts thus preheating air entering the combustion system. This can be by passing primary air through the deflector plate below the grate and/or secondary air through a gap between double side walls of the stove.
    Charcoal combusts in function of the available oxygen. Thus heat generation is a function of air supply to the charcoal grate. Action: get the right amount of air to the charcoal grate. To little will choke the combustion, too much will cool the flue gases. If power of the stove is too low, increase air supply by
    • making more holes in the grate.
    • adding a ‘Henson pig-tail’ vertical air-pass through the charcoal bed.
    Do not pile the charcoal up too high, as this will restrict air flow through the charcoal bed (this is influenced as well by the shape and particle size of the charcoal chunks).
    The combustion of charcoal goes from oxidizing C to CO, then in a subsequent step from CO to CO2. CO is a toxic gas and has still considerable energy value. Ensuring a complete combustion will increase energy output and reduce toxic emissions. Action: avoid CO emissions.
    Charcoal radiates heat but there is also considerable convection of hot flue gases. Action: Optimize transfer of created heat into the pot. Avoid obstructions between the radiating charcoal bed and the bottom of the pot (increase the view factor of the charcoal seeing the pot).
  • Criteria for Selecting Good Stoves

    Paal Wendelobo, January 2010

    What I feel is strongly needed by NGO's and others dealing with Household Energy for Developing Countries; is a list of about top10 actual fuels to be used and top 10 actual types of stoves to be used.

    Wood

  • ASEAN-US Next Generation Stove Workshop

    A couple of the presentations from the ASEAN-US NEXT-GENERATION COOK STOVE WORKSHOP, November 19, 2009.

    One is a great study by Dr. Modi of Columbia University of several stoves in Tanzania, and the other is some useful info from Tami Bond. Kirk also gave a very useful presentation, but unfortunately it was not included in the proceedings.

  • Cookstove Matrix

    Paul Anderson, March, 2009 How many of each major type of cookstoves exist in the developing societies(functioning in 2009)? The attached "draft" Matrix gives you my guesses. Perhaps YOU have additional input. Maybe we should change the Matrix. More columns, more lines. Or do you agree with what content? What I am attempting is to get us all reasonably "on the same page", literally on the same single page. Please look carefully at the two Notes at the bottom. In the general rank ordering, any stove type (or specific stoves within a type) might be shifted one or two columns to the left or right. But the question is, are the notes and orderings reasonably correct? There is no right or wrong, best or worst. By sheer numbers of units, the 3-stove fire is "best." It literally is "the competition to beat" for all of the other stoves. The file is an active MS Word document ( .doc), so you can change it as you please, but please indicate that you have altered it. (I desire neither the glory nor the blame for what you contribute.) It is a very small file and might be distributed with this message.

  • Stove Safety Panel at ETHOS - Viewpoints from corporations, standards institutes, and small developers

    Hello stoves community,

    At ETHOS 2009 we held a panel on stove safety, bringing in viewpoints from corporate standards development, national standards certification, and small to medium scale developers. The team led by Nathan Johnson (Iowa State University) included Crispin Pemberton-Pigott (New Dawn Engineering), Casper Thijssen (Philips), and Karabi Dutta.

    The panel gave a comparative analysis of how different stove industries (multinational corporations, medium-scale companies, NGOs, small developers, etc.) addressed fundamental stove safety questions. These topics included:

    a) applicability of standards and regulation;
    b) incentives and benefits
    c) facilities and equipment availability
    d) cost vs. benefit
    e) resulting action

    We determined that each type of industry has a different perspective that influences their path or actions towards a safer stove. And that all sub-industries may not produce safer stoves given the same incentive mechanisms or policies. As such more than one path to safety may be needed to reach the greatest amount of end-users (and producers). The panel ended the discussion with an overview present work in stove safety with recommendations for next steps.

    Please view the attached file for more details. I will be leading a group in 2009 to work on the following: assemble database of injury data, b) analyze incentive mechanisms, cost/ benefit, c) development of lab testing procedures for different stove categories, d) publication of findings/ results, and e) look for partnerships with international agencies to support safer stove design and production.

    Please contact me if you have any questions. There will be more updates to follow. Best,
    Nathan Johnson
    atlas@iastate.edu
    PhD Candidate, Mechanical Engineering, International Development
    Iowa State University

  • Natural Draft Biomass Gasifier Stove

    Design and Development of a Natural Draft Biomass Gasifier
    R. Krishna Kumar February 28, 2009

    Naturl Draft Gasifier - KumarNatural Draft Gasifier - Kumar

    N D G - BASICS & PRINCIPLES

    • Operates under the principlle of “ Chimney Effectt ”
    • Natural draft caused by density difference

    UNIQUE FEATURES COMPARED TO CONVENTIONAL SYSTEMS

    • No blower is required for the operation
    • Automatically takes the required quantity of air for Gasification
    • Convey the Producer Gas formed by Gasification - Naturally
    • Reduced fuel consumption compared to traditional chulas

    More detail, schematic pictures and testing information are in the attached pdfs and in the 2004 discussion:
    http://www.repp.org/discussiongroups/resources/stoves/kumar/ndg.htm

  • USING BIOMASS IN KEROSENE STOVE

    This is an experiment using biomass in the KEROSENE WICK STOVE. http://e-kerbiostoveexp.blogspot.com/ (for more photographs) The stove was lit at the top using a little amount of biomass soaked in kerosene. The fine holes of 1 to 2 mm located all along the inner and outer frame are useful in achieving very good bluish flames. The flames continued for 30 to 45 minutes duration. Only at the end the performance was bad, the option was that, a lid was used to shut down safely. The fire was very high (Reasons I am not sure). If one does not have enough kerosene, and in emergency one can use the kerosene stoves too with fine wood shavings as fuel. The end product is very good biochar. I am thankful to TOM REED for explaining the functioning of a Kerosene stove, which was the motivation for doing this experiment. http://listserv.repp.org/pipermail/stoves_listserv.repp.org/2009-January...
    Also see http://e-woodgasstovemodified.blogspot.com/

  • Design

    Biomass Cookstove Design

    Design Principles and Types of Stoves and Food Warmers

    Design Principles

  • Ten Design Principles for Wood Burning Stoves

    Ten Stove Design Principles, Larry Winiarski, Dean Still, Aprovecho, August 2005

  • Design Principles for Wood Burning Cook Stoves

    Design Principles for Wood Burning Cook Stoves, Aprovecho Research Center, Partnership for Clean Indoor Air, Shell Foundation, June 2005 (1MB pdf)

  • Design Principles for Retained Heat Cookers

    Design Principles for Retained Heat Cookers
    Dean Still, Aprovecho Research Institute, March 2005

    Guesses at Design Principles for a Retained Heat Cooker

    1.) Air exchanges are more important than insulation

  • Stoves A to Z

    Stoves by Name With Links

    Key:Common name - Organization/Reference - Countries - Fuels

    3 Stone (3 pierre amélioré)

Retained Heat Cooker

  • Design Principles for Retained Heat Cookers

    Design Principles for Retained Heat Cookers
    Dean Still, Aprovecho Research Institute, March 2005

    Guesses at Design Principles for a Retained Heat Cooker

    1.) Air exchanges are more important than insulation

This list is pretty close to alphabetical. Use the design menu to restrict the list of stories to the particular topics you are interested in.