Improved Cook Stove

Source: Center for Rural Technology, Nepal

improved cook stove

A cook stove is a device located in specific location where fuel is burnt for cooking purposes. The located space is known as kitchen. In Nepal, biomass energy: fuel wood, agro-residue and animal dung is used for cooking purpose. Use of traditional stoves such as “agenu” and “chulo” due to its low efficiency consumes more fuel increasing the burden on women. In Nepal women are mainly responsible for cooking and collection of biomass. Besides, use of biomass energy and low-grade biomass fuels leads to excessive levels of indoor air pollution. Women and children in particular are exposed to the smoke emission. This is one of the reasons for higher rates of infant mortality and morbidity. Release of incomplete carbon products in the atmosphere due to poor combustion of biomass fuels results in green house gas effect. More than 80% of the energy need of Nepal is met by fuel wood thus exerting immense pressure on the forest resources of the country.

What is a Traditional Cooking Stove?

Beehive Briquette – A Reliable Alternative Fuel

Presented by:

Dr. Krishna Raj Shrestha
Centre for Energy and Environment
Kathmandu, Nepal

Beehive briquette

Abstract: Biomass has been the prime source of fuel from time immemorial. About 85 percent of all energy consumed in Nepal at present is supplied by biomass. With the present crisis of fuel wood shortages, the rural population is depending more and more to the burning of loose agro-residues and cow dung for domestic cooking and other purposes. This is a highly polluting practice associated with health hazards. To solve the problem of fuel wood and associated deforestation, these agro-residues should be upgraded to convenient and smokeless fuels. In the present study a simple technology is developed for the production of beehive briquettes by the carbonization of the agro-forestry residues and mixing of the char with binders followed by briquetting. It provides smokeless domestic fuel easily ignitable with sustained uniform combustion. The test results and the tentative financial analysis are presented.

Keywords: Biomass, beehive briquette, agro-residues, briquetting, carbonization, char

Beehive briquette

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Crowd Power: The Latest In Renewable Energy

by Justin Thomas, Virginia

Vibrations from passing trucks, the rumbling of speeding trains and even the footfall of busy city commuters could be captured and converted into energy to light walkways and buildings, engineers say. A London-based architectural firm is working on a project that aims to harness the pulse of a city and use it as a renewable energy source.

Facility Architects director Clair Price says tens of thousands of people can pass through urban hubs like train stations during rush hour. “You don’t need to be a maths genius to realise that if you can harness that energy… you can actually generate a very useful power source that is currently being wasted,” she says. Price’s team has financial and technical support from several organisations for the proposal. “My first reaction when I saw it was wow, this is fantastic,” says Tony Bates, business development manager at Scott Wilson, an engineering consultancy firm based in the UK. “As an engineer of course, you can really see that this can really work.”

Bates and Price are now in the process of developing a joint partnership to make the idea a reality. The architectural team is working with university research groups to finish two vibration-harvesting prototypes by December. The first is a staircase that will contain hydraulic or piezoelectric technology in the risers. The technology will pick up kinetic energy from commuter footfalls and convert it into an electrical current.

Climbing stairs requires more force, which means there’s more energy to be tapped. Engineering experts from the University of Hull hope to develop a system that will convert at least 50% of the six to eight watts each person typically generates while walking. The current will be stored in a battery, which can be used to provide energy for lighting or electronic devices. The second prototype is a wireless lighting system that will use tiny generators with components designed to resonate at the same frequency as surrounding vibrations. The resonance will either move a magnet relative to a coil or put stress on a crystalline structure inside a generator to produce a current. Light-emitting diodes connected to such vibration harvesters could illuminate the underside of arches.

Via: Hugg and News In Science

 

Vibrations from passing trucks, the rumbling of speeding trains and even the footfall of busy city commuters could be captured and converted into energy to light walkways and buildings, engineers say. A London-based architectural firm is working on a project that aims to harness the pulse of a city and use it as a renewable energy source.

Facility Architects director Clair Price says tens of thousands of people can pass through urban hubs like train stations during rush hour. “You don’t need to be a maths genius to realise that if you can harness that energy… you can actually generate a very useful power source that is currently being wasted,” she says. Price’s team has financial and technical support from several organisations for the proposal. “My first reaction when I saw it was wow, this is fantastic,” says Tony Bates, business development manager at Scott Wilson, an engineering consultancy firm based in the UK. “As an engineer of course, you can really see that this can really work.”

Bates and Price are now in the process of developing a joint partnership to make the idea a reality. The architectural team is working with university research groups to finish two vibration-harvesting prototypes by December. The first is a staircase that will contain hydraulic or piezoelectric technology in the risers. The technology will pick up kinetic energy from commuter footfalls and convert it into an electrical current.

Climbing stairs requires more force, which means there’s more energy to be tapped. Engineering experts from the University of Hull hope to develop a system that will convert at least 50% of the six to eight watts each person typically generates while walking. The current will be stored in a battery, which can be used to provide energy for lighting or electronic devices. The second prototype is a wireless lighting system that will use tiny generators with components designed to resonate at the same frequency as surrounding vibrations. The resonance will either move a magnet relative to a coil or put stress on a crystalline structure inside a generator to produce a current. Light-emitting diodes connected to such vibration harvesters could illuminate the underside of arches.

Improved Cook Stove(ICS)

A cooking stove is a device in which fuel is burnt to cook food. Improved cooking stove is a device that is designed to consume less fuel and save cooking time, convenient in cooking process and creates smokeless environment in the kitchen.

ENERGY SCENARIO IN NEPAL

Total Energy Consumption	367.25 Million GJ (WECS, 2006)
Traditional Energy Sources	(322.105 mGJ)	87.71 %
Wood	(2386.96 mGJ)	78.78 %
Agri-residues	(13.964mGJ)	3.8 %
Animal Dung	(21.181 mGJ)	5.77%
Commercial	(43.195 mGJ)	11.76 %
Petroleum	(30.063 mGJ)	8.19 %
Coal	( 6.459 mGJ)	1.76 %
Renewables	(1.955 mGj)	0.58 %
Electricity	(6.673 mGJ)	1.82 %

Indoor air Pollution: 1.6 million people die each air because of indoor air pollution ( The World Health Report, WHO 2002).

Average Per capita Energy Consumption 15 GJ

Average Per capita Fuel wood consumption 559.5kg

Overall energy Demand is increasing by 3% per annum.

About 86 % of the total energy is used in domestic sector in which more than

90% is used for cooking purposes,

4.6% in industrial sector,

1.1% in trade sector,

3.9% in transport sector and agriculture sector accounts for 0.9% (Economic Survey, 2002).

Annually about 11 million tons of fuel wood are burnt for cooking alone and even with the low performance (11% fuel savings) estimates indicates that one ICS can save on average one metric ton of fuel wood annually (WECS, 1996).

During last five years, about 52,300 ICS have been installed in various parts of the country and the percentage of the rural households using ICS is still less than 10 % according to NLSS data.

Indoor air Pollution: 1.6 million people die each air because of indoor air pollution ( The World Health Report, WHO 2002)

Tree

A Tree living for 50 Years Generates –

Rs. 5.3 lakhs worth of Oxygen

Rs. 6.4 lakhs worth of soil Fertilizer

Rs. 6.4 lakhs worth of Soil Erosion Control

Rs. 10.5 lakhs worth of Air Pollution Control

Rs. 5.3 lakhs worth of shelter for Birds and Animals besides fruits and Vegetable

So When a Tree is Cut the net loss is worth more than Rs. 33 lakhs.[ Source: - Mucosol ]

.

Efficiency of Stove Net efficiency of a cooking stove depends upon various parameters and test conditions such as

• Altitude of test location
• Ambient temperature
• Atmospheric pressure
• Specific heat capacity of vessel taken for test
• Size of vessel
• Bottom and overall shape of vessel
• Weight of vessel and
• The amount of the cooking specimen (water) taken

Climate change factors

Climate change is any long-term significant change in the expected patterns of average weather of a specific region (or, more relevantly to contemporary socio-political concerns, of the Earth as a whole) over an appropriately significant period of time. Climate change reflects abnormal variations to the expected climate within the Earth’s atmosphere and subsequent effects on other parts of the Earth, such as in the ice caps over durations ranging from decades to millions of years.

In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate (see global warming). For information on temperature measurements over various periods, and the data sources available, see temperature record. For attribution of climate change over the past century, see attribution of recent climate change.

Climate change factors

Climate change is the result of a great many factors including the dynamic processes of the Earth itself, external forces including variations in sunlight intensity, and more recently by human activities. External factors that can shape climate are often called climate forcings and include such processes as variations in solar radiation, deviations in the Earth’s orbit, and the level of greenhouse gas concentrations. There are a variety of climate change feedbacks that will either amplify or diminish the initial forcing.

Most forms of internal variability in the climate system can be recognized as a form of hysteresis, where the current state of climate does not immediately reflect the inputs. Because the Earth’s climate system is so large, it moves slowly and has time-lags in its reaction to inputs. For example, a year of dry conditions may do no more than to cause lakes to shrink slightly or plains to dry marginally. In the following year however, these conditions may result in less rainfall, possibly leading to a drier year the next. When a critical point is reached after “x” number of years, the entire system may be altered inexorably. In this case, resulting in no rainfall at all. It is this hysteresis that has been mooted to be the possible progenitor of rapid and irreversible climate change.

Human Influence on Climate Change

Human industrial activities are believed to be adding to the amount of “greenhouse gases” naturally present in the atmosphere. There are mounting proofs that following the industrial revolution of the 18th and 19th centuries, which commenced in Britain and has expanded to several parts of the world, the amounts of of carbon dioxide, methane and other greenhouse gases in the atmosphere has increased somewhat. this leaves room for the suspicion that humans could have been contributing to Global Warming.

Based on scientific results and day-to-day physical evidences, global warming is no longer in dispute. With the the verdict of the fourth assessment report on climate change just released by the Intergovernmental Panel on Climate Change (IPCC), there is also very little contention that man contributes to the heating up of the Earth. However, the question that remains is: how much of the warming is caused by man?

Human activities that lead to production of GHGs are:

Agriculture: During agricultural practices, methane gas (a GHG) is produced when bacteria decomposes organic matter. It has been estimated that close to a quarter of methane gas from human activities result from livestock and the decomposition of animal manure. Paddy rice farming, land use and wetland changes are also agricultural processes that could contribute to the release of methane to the atmosphere. Use of fertilizers for agricultural activities also lead to higherNO2 concentrations.

Deforestation: With the growth of industrial activities has been worldwide deforestation. As part of the photosynthetic process, trees abstract carbon dioxide from the air and release oxygen back to the atmosphere. with deforestation, the number of trees available to take in CO2 from the atmosphere has greatly reduced, leading to more available CO2 and increased greenhouse effect. When forests are cleared, most of the carbon in the burned or decomposing trees escape back into the atmosphere

Fossil Fuels: Fossil fuels is widely used to power our modern day engines and locomotives. The burning of coals, natural gas and oil yields most of the energy used to produce electricity, heat houses, run automobiles and power factories. The burning of fossil fuels to obtain energy to drive these engines lead to production of tremendous amount of CO2 which is released to our environment and increasers the concentration of CO2 in the atmosphere. It is believed that CO2 generated from the burning of fossil fuel accounts for about three-quarters of the total CO2 emissions from human activities.

Refrigeration/Fire Suppression/Manufacturing: Establishments and Industries used to use chlorofluorocarbons (CFCs) in refrigeration systems, and CFCs and halons in fire suppression systems and manufacturing processes.

Other human factors leading to release of GHGs (particularly methane) to the atmosphere include pipeline losses, landfill emissions and septic systems that enhance and target the fermentation process also are major sources of atmospheric methane;

Indicators of the Influence of Human Activities on Climate Change:

Measurements of the concentrations of CO2, CH4, NO2 and other GHGs in the atmosphere over time suggests that these concentrations have been on the increase since the beginning of the industrial revolution that began in the 18th century. A couple of the graphical data is presented on this page to illustrate that man’s activities are possibly contributory to the heating up of our Earth.

Hydrogen fuel

Hydrogen fuel refers to use of hydrogen for its combustive qualities as a fuel and energy carrier. The hydrogen must first be broken out from its compound form with oxygen as water (H2O) using electrolysis or gathered by other means as it does not naturally occur by itself. Hydrogen cannot be mined or drilled as with fossil fuels and requires more energy input to produce it than is generated with its combustion.

Advocates of hydrogen fuel believe solar power, wind power or other renewable and environmentally friendly technologies can be used to make hydrogen fuel. The hydrogen can then be transported and used for various applications. This might have environmental advantages over burning fossil fuels for motive power and other uses.

Hydrogen is a potential fuel for motive power, including cars, boats and airplanes. It can also be used in smaller devices using fuel cells. Some environmentalists believe a hydrogen economy could greatly reduce the emission of carbon dioxide and therefore play a major role in tackling global warming. Countries without oil, but with renewable energy resources could use hydrogen as a clean burning energy store.

Advantages of hydrogen fuel

• When hydrogen is burned, the only emission it makes is water vapor, so a key advantage of hydrogen is that when burned, carbon dioxide (CO2) is not produced.
• Clearly, hydrogen is less of a pollutant in the air because it omits little tail pipe pollution.
• Hydrogen has the potential to run a fuel-cell engine with greater efficiency over an internal combustion engine.
• The same amount of hydrogen will take a fuel-cell car at least twice as far as a car running on gasoline.

Disadvantages of hydrogen fuel

• Currently, it still costs a considerable amount of money to run a hydrogen vehicle because it takes a large amount of energy to liquefy the fuel.
• Research shows that cars could store hydrogen in high pressure tanks like those used for compressed natural gas. It would need to be packed tightly into a car’s tank in order to avoid countless trips to the filling station every few miles.
• The Department of Energy’s goal is to produce hydrogen at $2 to $3 per gallon by 2015. Right now, the cost per gallon is between $6 and $8.

Fossil fuel and it’s impact on the environment

The technical definition of fossil fuels is “incompletely oxidized and decayed animal and vegetable materials, specifically coal, peat, lignite, petroleum and natural gas”. The technical definition of fuel is “material that can be burned or otherwise consumed to produce heat”. In our modernized world, fossil fuels provide vast luxurious importance. We retrieve these fossil fuels from the ground and under the sea and have them converted into electricity. Approximately 90% of the world’s electricity demand is generated from the use of fossil fuels.

There is a growing concern regarding the collaboration between fossil fuels and environmental pollution. Debates regarding this contamination have become commonplace in today’s effort to sustain the earth’s health. Fossil fuels are not considered a renewable energy source and aside from the environmental impact, the cost of retrieving and converting them is beginning to demand notice. Seemingly this issue has many different angles that need to be addressed in order to ensure future generations a sustainable living.

Environmental implications:

Environmental impacts of fossil fuel are coupled to a number of naturally irreversible factors that are detrimental both on local and global scale. They have been categorized and described individually in the following section:

a) The increase of green house effect; Global warming; Climate Change

Carbon dioxide (CO2) is a “greenhouse gas,” trapping heat in the lowest part of the earth’s atmosphere. This contributes to “global warming” – the average temperature of the earth slowly increases, affecting ecosystems across the globe. Climate change is responsible for huge economical consequences. Between the 1960s and the 1990s, the number of significant natural catastrophes such as floods and storms rose nine-fold, and the associated economic losses rose by a factor of nine. Figures indicate that the economical losses as a direct result of natural catastrophes over 5 years between 1954 and 1959 were US$35 billion while between 1995 and 1999 these losses were around US$340 billion [1]. Europe’s extreme summer heat wave was the biggest single event in the year 2003—costing more than $10 billion in agricultural losses alone and killing some 20,000 people [1].

Continuity of Flow

Matter is neither created nor destroyed. This principle conservation of mass can be applied to a flowing fluid.

Considering any fixed region the flow constituting a control volume.

Mass of fluid entering per unit time=  Mass of fluid leaving per unit time +   Increasing/decreasing of mass of fluid in the control volume per unit time

For steady flow, the mass of fluid in the control volume remains constant and relation reduces to

Mass of fluid entering per unit time = Mass of fluid leaving per unit time

Applying this principle to steady flow in a stream tube having a cross sectional area small enough for the velocity to be considered as constant over any given cross-section, for the region between sections I and 2, since there can be no flow through the walls of a stream tube;

Mass entering per unit time at section 1 = Mass leaving per unit time-at section 2

Suppose that at section 1 the area of the stream tube is δA₁, the velocity of the fluid u₁ and its density r₁while at section 2 the corresponding values are δA₂, u₂ and ρ₂while

Mass entering per unit time at 1 = δA₁ u₁ ρ₁

Mass leaving per unit time at 2 = δA₂ u₂ ρ₂

δA₁ u₁ ρ₁= δA₂ u₂ ρ_{2 =} Constant

This is the equation of continuity for the flow of a compressible fluid through a any fixed region in stream tube, u₁ and u₂ being the velocities measured at right angles to the cross-sectional areas δA₁ and δA₂.

For the flow of a real fluid through a pipe or other conduit, the velocity will vary from wall to wall.  However, using the mean velocity, the equation of continuity for steady flow can be written as

δA₁ u₁ ρ₁= δA₂ u₂ ρ_{2 =} m dot.

where δA₁ and δA2 are the cross-sectional areas and m is the mass rate of flow.

If the fluid can be considered as incompressible, so that ρ₁ =ρ₂ equation reduce to,

δA₁ u₁ = δA₂ u_{2 =} Q dot

The continuity equation can also be applied to determine the relation between the flows into and out of a junction. In Figure, for steady conditions,

Total inflow to junction = Total outflow from junction,

ρ₁Q₁ =ρ₂Q₂ +ρ₃Q₃

For an incompressible fluid,  ρ1 =ρ2 =ρ3 so that

Q₁ =Q₂ +Q₃

A₁`v<sub>1</sub>= A<sub>2</sub>`v₂+ A₃v₃

In general, if we consider flow towards the junction as positive and flow away from the junction as negative, then for steady flow at any junction the algebraic sum of all the mass flows must be zero:

∑ρQ=0