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− | [[File:GIZ HERA Cooking Energy Compendium small.png|left|831px|GIZ HERA Cooking Energy Compendium|alt=GIZ HERA Cooking Energy Compendium small.png|link=GIZ HERA Cooking Energy Compendium]]<br/> | + | |
| + | [[File:GIZ HERA Cooking Energy Compendium small.png|left|831px|GIZ HERA Cooking Energy Compendium|alt=GIZ HERA Cooking Energy Compendium small.png|link=GIZ HERA Cooking Energy Compendium]]<br/><br/><!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Cooking Energy System |'''[[GIZ HERA Cooking Energy Compendium#Cooking Energy Technologies and Practices|Cooking Energy System]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Cooking Energy Technologies and Practices|Cooking Energy System]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Basics |'''[[GIZ HERA Cooking Energy Compendium#Basics about Cooking Energy|Basics]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Basics about Cooking Energy|Basics]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Policy Advice |'''[[GIZ HERA Cooking Energy Compendium#Policy Advice on Cooking Energy|Policy Advice]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Policy Advice on Cooking Energy|Policy Advice]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Planning |'''[[GIZ HERA Cooking Energy Compendium#Planning Cooking Energy Interventions|Planning]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Planning Cooking Energy Interventions|Planning]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | ICS Supply |'''[[GIZ HERA Cooking Energy Compendium#Designing and Implementing Improved Cookstoves .28ICS.29 Supply Interventions|Designing and Implementing ICS Supply]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Designing and Implementing Improved Cookstoves .28ICS.29 Supply Interventions|Designing and Implementing ICS Supply]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Woodfuel Supply |'''[[GIZ HERA Cooking Energy Compendium#Designing and Implementing Woodfuel Supply Interventions|Designing and Implementing Woodfuel Supply]]''' {{!}} | [[GIZ HERA Cooking Energy Compendium#Designing and Implementing Woodfuel Supply Interventions|Designing and Implementing Woodfuel Supply]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Climate Change |'''[[GIZ HERA Cooking Energy Compendium#Climate Change Related Issues|Climate Change]]''' | [[GIZ HERA Cooking Energy Compendium#Climate Change Related Issues|Climate Change]] {{!}} | }} <!-- |
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| + | -->{{#ifeq: {{#show: {{PAGENAME}} |?Hera category}} | Extra |'''[[GIZ HERA Cooking Energy Compendium#Climate Change Related Issues|Extra]]''' | [[GIZ HERA Cooking Energy Compendium#Climate Change Related Issues|Extra]] }} |
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| = Main Principles<br/> = | | = Main Principles<br/> = |
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| <u>The main principles for efficient firewood management are:</u> | | <u>The main principles for efficient firewood management are:</u> |
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| #Remove the moisture out of the firewood; | | #Remove the moisture out of the firewood; |
| #Increase the surface of the firewood; | | #Increase the surface of the firewood; |
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| <p style="text-align: center">'''more firewood = more heat generation = faster cooking'''</p> | | <p style="text-align: center">'''more firewood = more heat generation = faster cooking'''</p> |
| However, in any kind of stove with enclosed combustion chamber one can observe a point where this equation does come to its limits. Instead of an increase of heat, one can suddenly observe more smoke, a darker flame colour and less heat. There are several effects which can contribute to this observation: | | However, in any kind of stove with enclosed combustion chamber one can observe a point where this equation does come to its limits. Instead of an increase of heat, one can suddenly observe more smoke, a darker flame colour and less heat. There are several effects which can contribute to this observation: |
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| *Fresh wood is much colder than the wood in the reactor. If a lot of fresh wood is added to the combustion chamber, it cools down the temperature of the reactor until it is heated up to the same level. | | *Fresh wood is much colder than the wood in the reactor. If a lot of fresh wood is added to the combustion chamber, it cools down the temperature of the reactor until it is heated up to the same level. |
| *Additional wood will be placed on top of the wood which is already in the reactor. Hence it might cover some part of the surface of the already heated wood, reducing the space for the reaction between the air and the wood. | | *Additional wood will be placed on top of the wood which is already in the reactor. Hence it might cover some part of the surface of the already heated wood, reducing the space for the reaction between the air and the wood. |
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| '''Recommendation:''' | | '''Recommendation:''' |
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| *In an improved firewood cook stove, it is sufficient to start the fire with three sticks of (small) wood only. | | *In an improved firewood cook stove, it is sufficient to start the fire with three sticks of (small) wood only. |
| *Once the fire is going, the heat can be regulated by the number of sticks. Do not go beyond 3 sticks at a time. | | *Once the fire is going, the heat can be regulated by the number of sticks. Do not go beyond 3 sticks at a time. |
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| |} | | |} |
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| <br/> | | <br/> |
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− | These are fuel-specific recommendations for firewood, but they apply as well for other processed types of solid biomass | + | These are fuel-specific recommendations for firewood, but they apply as well for other processed types of solid biomass. |
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− | -> [[Cooking with Non Timber Solid Biomass Fuels|Cooking With Non Timber Biomass Fuels]]
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| Find other recommendations on how to efficiently manage the cooking process | | Find other recommendations on how to efficiently manage the cooking process |
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| -> [[General Kitchen Management Practices|General Kitchen Management Practices]] | | -> [[General Kitchen Management Practices|General Kitchen Management Practices]] |
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| = Further Information<br/> = | | = Further Information<br/> = |
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− | '''Fact Sheet Firewood Management''' | + | '''Fact Sheet Firewood Management''' |
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| This fact sheet is a compilation of energy-saving practices and was developed by the Integrated Food Security Project in Malawi. Every practice is explained in detail and addition is provided regarding the reasons of fuelwood savings and additional benefits. | | This fact sheet is a compilation of energy-saving practices and was developed by the Integrated Food Security Project in Malawi. Every practice is explained in detail and addition is provided regarding the reasons of fuelwood savings and additional benefits. |
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| | [[File:GTZ 2a FS firewood management 2010.pdf|180px|RTENOTITLE]] | | | [[File:GTZ 2a FS firewood management 2010.pdf|180px|RTENOTITLE]] |
| |} | | |} |
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| = References<br/> = | | = References<br/> = |
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− | This article was originally published by [http://www.giz.de/Themen/en/12941.htm GIZ HERA]. It is basically based on experiences, lessons learned and information gathered by GIZ cook stove projects. You can find more information about the authors and experts of the original “Cooking Energy Compendium” in the [[Imprint - GIZ HERA Cooking Energy Compendium|Imprint]]. | + | This article was originally published by [http://www.giz.de/fachexpertise/html/2769.html GIZ HERA]. It is basically based on experiences, lessons learned and information gathered by GIZ cook stove projects. You can find more information about the authors and experts of the original “Cooking Energy Compendium” in the [[Imprint - GIZ HERA Cooking Energy Compendium|Imprint]]. |
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| <references /> | | <references /> |
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| [[GIZ HERA Cooking Energy Compendium|--> Back to Overview GIZ HERA Cooking Energy Compendium]] | | [[GIZ HERA Cooking Energy Compendium|--> Back to Overview GIZ HERA Cooking Energy Compendium]] |
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− | [[Category:Cooking_Energy]]
| + | {{#set: Hera category=Cooking Energy System}} |
− | [[Category:GIZ]]
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− | [[Category:Wood_Energy]]
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| [[Category:Cooking_Energy_Compendium_(GIZ_HERA)]] | | [[Category:Cooking_Energy_Compendium_(GIZ_HERA)]] |
| + | [[Category:Firewood]] |
| + | [[Category:Energy_Efficiency]] |
| + | [[Category:Wood_Energy]] |
| + | [[Category:Cooking_Energy]] |
Firewood is a valuable source of energy, whether it is collected or bought on the market. It involves financial or time resources of the household to obtain it. Even users of traditional cookstoves can save firewood by applying the following firewood management techniques. Clever firewood management can save approximately 20 - 30% of the total cooking fuel requirement.
Freshly collected firewood contains up to 50% water. This water not only has no heating value, it is also consuming 25 - 35% of the energy of the wood to remove the moisture within the cooking process. Hence, wet wood has a low power output and a low temperature. Smoke is the visible indication of this wasteful practice.
Firewood does not burn as such. It is the gasses generated in the process of its decomposition. For it to decompose, the wood has to be heated. Thick pieces of wood require a lot of heat to reach these temperatures. Hence, it takes a lot of time until the wood burns efficiently. Smoke is an indication that the decomposition of the firewood has not yet progressed sufficiently.
A wood-fire is fuel regulated. To increase the heat output, more fuel can be supplied to the combustion chamber. In short:
However, in any kind of stove with enclosed combustion chamber one can observe a point where this equation does come to its limits. Instead of an increase of heat, one can suddenly observe more smoke, a darker flame colour and less heat. There are several effects which can contribute to this observation:
In most cooking processes we can distinguish high-power phases (e.g. to bring a cold pot to boiling point) and low-power phases (e.g. for keeping a hot pot at the boiling point = simmering). Inexperienced cooks tend to use a lot of wood in the stove all the time, regulating the heat transfer through modification of the distance between the pot and the stove. This is a very wasteful practice.
It is a common observation that wood is still burning in a stove after the cooking has been completed. This wood should be extinguished once the fire is no longer needed. This applies as well for any burning wood which is removed from the fire e.g. at the start of the simmering phase.
These are fuel-specific recommendations for firewood, but they apply as well for other processed types of solid biomass.