TRIBHUVAN UNIVERSITY

INSTITUTE OF ENGINEERING

PULCHOWK CAMPUS

A LABORATORY REPORT

ON

TRADITIONAL COOK STOVE (TCS)

SUBMITTED BY: SUBMITTED TO:

Gogan Bdr. Hamal Dr. Krishna Raj Shrestha

065/ MSREE/504

Date: 2066/04/08

Title: Testing of Efficiency of Traditional Cook Stoves (TCS) Objective:

To determine the efficiency of the Traditional Cook Stove. Apparatus: Mud Brick TCS Set-up Aluminium Pots (P1 and P2) Thermometers Weighing Balance Stop watch

Background Information:

A cook stove is a device located in specific location where fuel is burnt for cooking purposes. The located space is known as kitchen. Cook stoves are the most common way of cooking and heating food in developing countries. In Nepal, biomass energy: fuel wood, agri-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.

Many rural households use traditional cooking stoves (often only a hole in the ground) that use firewood, agro residues and cow dung as fuel. These stoves have certain inherent defects: ·

• They are less than 10 percent efficient (in using the energy store in wood); • The produced smoke stays in the kitchen due to absence of vent pipe and ill ventilation,

which is harmful to the health of users and their families; • Utensils and clothes are blackened by soot; • The open fire results in risk of accidents with children burn and/or household fire; • The stove needs regular blowing

A modified version of the traditional cooking stove is the Improved Cook Stove (ICS). Certain features have been modified to make them more efficient with respect to fuel wood consumption, make them convenient for cooking and much safer from a health point of view.

Besides the high expense, another problem of cooking over an open fire is the increased health problems brought on from the smoke, particularly lung and eye ailments, but also birth defects. Replacing the traditional cook stove with an improved one and venting the smoke out of the house through a chimney can dramatically improve a family’s health.

Deforestation and erosion are often the end result of harvesting wood for cooking fuel. The main goal of most improved cooking stoves is to reduce the pressure placed on local forests by reducing the amount of wood the stoves consume. Additionally, the money a family spends on wood or charcoal translates into less money being available to be spent on food, education, and medical care; so an improved cooking stove is seen as a way of boosting a family's income.

The study of Traditional Cooking Stoves(TCS) cannot be bypassed while emphasizing the importance of Improved Cook Stoves(ICS).The concept of ICS is grounded on traditional cook stoves which many of Nepalese community use even at present burning wood and charcoal in three-stone open fires. These simple stone-based stoves allow the fire, heat, smoke, and energy to escape around the sides. Similar stoves with mud-walls & coverings or circular earth space dug down-to certain depth use three-legged metallic support is widely in use. They are inefficient, unstable, and are the cause of multiple burns and smoke related illnesses.

Traditional Cook Stoves

Women and children are the victims of poisonous smoke that fill their houses every day, where they cook, play and study. Some of the burns seen in villages, caused by falling into the open fires, are horrendous and could have been prevented. The indoor air pollution caused by the release of carbon monoxide triggers nasty illnesses like Acute Respiratory Infection (ARI) including pneumonia; cor pulmonalae; conjunctivitis; adverse reproductive outcomes (low-birth weight and increased still-births); lung cancer; increased infant morbidity/mortality; depressed immune response; chronic obstructive lung diseases (COLD) - bronchitis, emphysema, asthma, and skin and eye infection.

With this backdrop, development and adoption of Improved Cook Stoves seems in the scenario. AEPC mentions: A history of ICS development program in Nepal dates back to 1950s with the introduction of some Indian models. Since then, a number of Improved Cooking Stove Programs (ICSPs) have been promoted in rural communities of Nepal. A variety of stove designs with different dissemination strategies are promoted both by the Government and the NGO's. During 1980s, interest and efforts were revived when the National Planning Commission included ICS in an attempt to address the pressing fuelwood problem. The government’s concern for fuelwood conservation was also reflected with the inclusion of ICS dissemination efforts as an important component of FAO assisted Community Forestry Development Project (CFDP) in 1981.

The ICS is extremely simple and straight forward, easy to build locally, and showing immediate effect, making it a very successful programme An improved cooking stove has a closed design, making the wood burn more effectively, and a chimney to lead the smoke out of the house. An improved cooking stove is a more effective and healthy way of using firewood compared to traditional stoves. "An improved cooking stove saves 20-30% of firewood. It also makes cooking faster"

 

Improved Cook Stoves

Another advantage of improved cooking stoves is the chimney that leads the smoke out of the kitchen, saving women and children from respiratory diseases that often go hand in hand with the traditional way of cooking.

The direct and indirect benefits of ICS includes: increased thermal efficiency, the conservation of forests by cutback in firewood consumption, reduction in women’s labour, reduction in indoor air pollution and hence smoke-released health disorders, prevention of fire hazards, reduction of cooking time.

Finally, it is necessary to know all the features of traditional cook stoves so that we can compare these with those of improved cook stoves and deduce further conclusions. So, an experiment of water boiling test must be performed in a TCS and determine its features such as efficiency, pollution index and others. Then, further analysis can only be done regarding the necessity of implementation of improved cook stove that will address the limitations and problems imposed by TCS.

Theory:

Water Boiling Test

The water-boiling test is a laboratory test, which can be used to compare the performance of two

or more stoves under similar controlled conditions, or the same stove under different conditions.

It simulates the boiling/simmering type of cooking to some extent only. As a result, it does not

necessarily reflect the actual stove performance, when food is cooked. A known quantity of

water is heated on a cook stove. The volume of water evaporated after complete burning of the

fuel is determined.

Heat Utilization (HU) Efficiency is calculated so as to check the performance of ICS. This is percentage of heat utilized to total heat supplied to the system.

Mathematically,

[Cw x mi (Tf-Ti) + (L x me)] HU efficiency = x 100%

[(Ef x Wf)/(1+0.01×β)]- (29000 x mc)]

Where,

Cw = Specific hat of water mi = Weight of water taken initially Tf = Final temperature of water Ti = Initial temperature of water L = Latent heat of water me = Weight of water evaporated Ef = Calorific value of firewood Wf = Firewood used mc = Mass of charcoal left β = moisture content on wood

Observations:

Standard data: Room temperature = 28°C Calorific value of firewood (heat value of fuel) (Ef) = 16.5 MJ/kg= 16500KJ/kg Calorific value of charcoal (heat value of kindling) = 29 MJ/kg Specific heat of water (Cw) = 4.18 KJ/kgK Latent heat of water at boiling (L) = 2256 KJ/kg Data from Experiment: Type of Stove : Traditional Cook Stove For Pot1:

Weight of fire-wood taken = 3.0 kg Moisture content of wood(β) = 15 % Weight of pot & lid = 0.9 kg Weight of pot, lid & water (initially) = 5.9 kg Weight of water taken (mi) = 5.9-0.9=5 kg Weight of pot, lid & water at the end = 5.85kg Weight of water at the end (mf) = 5.85-0.9 = 4.95 kg Weight of water evaporated at the end of test (me) = (mi- mf) = 0.05 kg Fire wood left = 0.7 kg Fire wood used (Wf) = 2.3 kg Coal left (mc) = 0.185 kg

Time-Temperature Data for WBT Time(min) Water Temperature for 1st Pot

(P1) (oC)

0 28

5 30

10 33

15 41

20 55

25 67

30 72

35 80

40 90

45 93

50 94

[Cw x mi (Tf-Ti) + (L x me)] HU efficiency = x 100%

[(Ef x Wf)/(1+0.01×β]- (29000 x mc)] [4.18×5× (94-28) +2256× 0.05] × 100 = [(16500×2.3)/(1+0.01×0.15)]-(29000×0.185)

1492.2 × 100

=

32528.16

= 4.5874 %

0102030405060708090100

0 10 20 30 40 50 60

Tempe

rature (oC)

Time (minutes)

Time  Temperature Plot for  Pot 1

For Pot 2: Weight of fire-wood taken = 3.0 kg Moisture content of wood(β) = 15 % Weight of pot & lid = 0.8 kg Weight of pot, lid & water (initially) = 5.8 kg Weight of water taken (mi) = 5.8-0.8=5 kg Weight of pot, lid & water at the end = 5.4 kg Weight of water at the end (mf) = 5.4-0.8=4.6 kg Weight of water evaporated at the end of test (me) = (mi- mf) = 0.4 kg Fire wood left = 0.7 kg Fire wood used (Wf) = 2.3 kg Coal left (mc) = 0.185 kg

Time-Temperature Data for WBT Time(min) Water Temperature for 2nd Pot

(P2) (oC)

0 28

5 30

10 35

15 49

20 60

25 73

30 81

35 90

40 94

45 94

50 94

[Cw x mi (Tf-Ti) + (L x me)] HU efficiency = x 100%

[(Ef x Wf)/(1+0.01×β]- (29000 x mc)] [4.18×5× (94-28) +2256× 0.4] × 100 = [(16500×2.3)/(1+0.01×0.15)]-(29000×0.185)

2281.8 × 100

=

32528.16

= 7.015 %

Graphical Representation of Time-Temperature Data:

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60

Temperature

Tempe

rature ( 

o C)

Time (minutes)

Temperature  Vs  Time  Plot

Hence,

Total HU efficiency for TCS= 4.5874 + 7.015 =11.6024 %

Analysis:

The experimental results are based on common data assumptions and are subjected to further analysis for more precision. The firewood used might not have exactly 16500KJ/Kg calorific value. It could be less, but for analysis purpose it has been considered so. This can be a reason for comparatively less efficiency calculated.

Another part to consider is its health-friendly performance which has substantially dropped the situations of health hazards and losses due to uncontrolled fire.

Conclusion:

Hence the heat utilization efficiency of the traditional cook stove was measured in lab with the help of water boiling test and found to be 11.6024 %.

Limitations:

Instruments used for the data recording are above the level of bad. This has acute effect on calculations. Also, whole the experiment was taken in rough calculation compromising certain level of inaccuracy however it was considered to be one of the analytical practical experiences.