Physics by yurtgc548



       Group 4 Project

      Done by Group 3
       Research Question

Investigating the best energy
sources for domestic use in rural
                             Why ?
Energy can neither be created nor destroyed, but it can be lost.
As we evolve technologically, one of the biggest challenges we
face is conserving energy. In our experiment, we will be
investigating the most feasible methods to supply energy to
village households – in this we will include present
methods used as well modern developments that have not
yet touched such grass root levels. The advantage to such an
analysis is that by considering the supply and use for
individual households we are looking at a relatively small
electric supply – this allows us to investigate sources that normally
cannot be implemented as larger scales have a whole different set of
The primary domestic energy uses are cooking and heating
brick kilns.
At present the fuels used are cow dung (gobbar), wood
 (kantada and kata - plants), and Liquefied Petroleum Gas
In our experiment we have tested the viability of these
and as possible future developments we have also tested the
viability of two renewable sources: solar power and wind
                          Subject Division
Our study involves two crucial factors.The first is the scientific compatibility of the energy sources
and the second, which is the crux of our evaluation, is the economic compatibility.

  Tested different bovine dung qualities to see highest fuel efficiency
  Investigated reasons for mixing dry grass with dung to see why there
    is an increase in its efficiency
  Investigated different wood types to see energy content
  Investigated the relationship between fodder and dung to see what
    type of fodder would give the most efficient dung
  Investigated feasibility of renewable sources: solar and wind power
           Domestic forms of energy such as manure and firewood are used as fuel in rural India.

Dung, being readily available for all farmers that own cows or bulls, becomes a regularly used fuel.

Firewood is the most traditional type of fuel used for domestic use. Hence, our aim was to find the

most efficient energy source from cow dung, dung from a bull and firewood, in Jamnagar.

           We learnt that cows in the village ‘goshala’ have a diet rich in carbohydrates, consisting

of jowar, corn and dry and green fodder as they are the primary source of milk for the villagers.

Bulls, used in the field for ploughing, are fed more proteins including grass, groundnut shoots and

dry fodder as they require more strength on the field.
We predicted that the cow dung from the ‘goshala’ would yield more energy than the
dung from the farm. This is because the cows in the cow shed are fed a rich
carbohydrate diet, keeping in mind that carbohydrates have a higher calorific value
than proteins. This means that if a carbohydrate and a protein of the same mass were
to be heated for the same amount of time, the substance heated by the
carbohydrates would create a higher net increase of temperature than that of a

We also expected wood to have give out the highest amount of heat, for the simple
reason that it is the most commonly used in households all around the world, and
hence must be a more effective fuel than dung, besides being more commonly
available around the world.
• Starting off, we brainstormed to decide which domestic fuels we should
  consider. On short listing two different types of cow dung and firewood,
  we planned an experiment that tested the most efficient fuel by analyzing
  which one increased the net temperature of 100 ml of water the most in
  an equal time span.
• Hence, we visited the goshala, to investigate the constituents of the cows’
  daily diet. We then collected a sample of the dung, along with some
  fodder. These cows were chosen by us because they are used for milking
  and are fed a high carbohydrate diet. We also collected samples of dried
  grass and an actual dung cake that is used by the villagers
• Then, we visited a farm to collect a sample of cow dung, from cows which
  are fed a high protein diet and are used in the field for ploughing.
• After we obtained all the required samples, we returned to the laboratory
  to carry out our experiments.

1.    Tripod stand
2.    Retort stand
3.    Conical flask
4.    Thermometer
5.    Evaporating dishes
6.    Wire gauze
7.    Bunsen burner
8.    Samples of cow dung
9.    Samples of fire wood
10.   Dry grass
1.    Measure 100 ml of water in a conical flask.
2.    If the fuel sample is wet dung, place it in an oven for 20 minutes (to dry).
3.    Take an amount of the fuel sample and mass it. If the fuel is such that it
      unfeasible to place it on the mesh, then:
         1.   Mass an evaporating dish.
         2.   Place the sample into the dish and mass it again.
4.    Mass the empty conical flask, and then mass the conical flask with the water
      inside it.
5.    Set up an apparatus where the conical flask is held, with a retort stand, 5 cm
      above a wire gauze supported by a tripod stand, under which is a bunsen
6.    Place the fuel sample directly below the conical flask and above the flame of the
      bunsen burner.
7.    Record the initial temperature using a thermometer.
8.    Heat the water for 90 seconds.
9.    After this record the final temperature of the water.
10.   Repeat the process with the other fuel samples.
                                           Raw Data:
 The following are the readings and values taken from the experimental procedures:

 Volume of water = 100ml             Time heated for = 90 sec

                           Dung                                                               Actual
                           from       Dung from            Thin         Thick         Dry    cowdung
                           field       cowshed          firewood      firewood       Grass     cake
    Temperature             43             45               31             32         32       42
    Temperature             50             58               37             43         41       52

Volume of water                                                                      100
                           100 ml        100 ml          100 ml         100 ml                100ml
   used (±1ml)                                                                        ml

 Mass of Conical
                           53.34         56.45            57.76          55.2        57.5     54.89
 Flask (±0.01g)

 Mass of Conical
   Flask+Water             149.63       148.23           152.49         148.94                150.23

    Mass of Fuel
                            14.5         11.07            12.21          21.19       4.91     11.61
Sample (±0.01g)
                        Data Processing:
c (of water) = 4.2 J/g°C

                   Dung     from       Thin      Thick             Actual
                   from    cowshe    firewoo   firewoo    Dry     cowdun
                   field      d          d         d     Grass     g cake

  Mass of Water
                   96.29    91.78     94.73     93.74    86.64     95.34
  (m) (±0.02g)

        Rise in
   Temperature      7        13        6         11        9        10
  (ΘR) (±2°C)

 Heat Given Out
                   2830.                       4330.78   3274.9
    = mcΘR (J)             5011.18   2387.19                      4004.28
                      92                            8        9
  (±0.04 g°C)

 Heat Given Out
  per unit mass    195.2
                           240.59    195.51    204.37    667.00   344.89
           (J/g)       4
                               Heat Given Out = mcΘR (J) (±0.04 g°C)

    5000                                       4330.788
    4000                                                   3274.99
             2830.92                                                        Heat Given Out = mcΘR (J)
    3000                            2387.19                                 (±0.04 g°C)


                                                           wd ss
        fi e





                                         fi r
                           f ir









The highest yield per mass of fuel was obtained from dry grass. Hence our hypothesis pertaining to
this was proved wrong. However, this does not have much bearing on dry grass’s usefulness as a fuel
because it gave out a lot of smoke and also burned far too quickly (a large quantity of grass was nearly
used up in 90 seconds), while the dung and the firewood remained largely unused.

The dung samples that we collected yielded low amounts of heat, as compared to that of an actual
dung cake. The reasons for this are:

•The dung we collected was fresh, and thus was wet.

•The dung cake is made by mixing dry grass in with it, thus improving it’s ability to burn and it’s yield.

There were large amounts of smoke released from the grass and the dung when being burnt, causing
us discomfort and suffocation. The firewood released very little smoke, and hence this could offer
another reason for its popularity as a domestic fuel when compared to the others.
We found there to be a relation between the cattle’s diet and the quality of its dung as
a fuel. The grass used to feed the cows in the cowshed is sorghum which is a high
protein, medium fiber feed containing fats, while the field cows are fed a diet of
50%high protein & high fiber feed and 50% groundnut shoots (high in protein, low

The presence of fiber allows the animal to use more of the energy that may be
obtained from the fuel. Proteins also have a lower yield of energy per unit mass than
carbohydrates or fats. Hence, the field cows were fed proteins to help them build up
the essential muscle mass and fiber to help them use as much of that energy as
possible, thus not allowing many energy providing foods to make it into the dung. It is
the opposite of the goshala cows: they were fed more carbohydrates and fats with
little fiber, thus allowing a fair amount of carbohydrates to make it into the dung.
                       Fair Test
We made sure that the dung sample was taken from an
  appropriate cow.
• We made sure that the conical flask was 5 cm above the wire
  gauze for each experiment
• We made sure that the water was heated for the same time
  span, using the different samples
• The initial and final mass of dung was weighed
• The fans were off at all times
• We used the same amount of water for each attempt
                              Error Evaluation
The systematic error value is quite negligible. However, there are a number of other
  sources of error which could have significantly altered our results.

• Random errors:

• One cannot be sure that the cow ate only the feed that was given to them and nothing
  else. The cows from the goshala were allowed to roam freely through the area, and
  hence may have consumed any number of other types of food.

• We did not take into consideration the water purity/ constituents in the different areas.

• The dung was not completely dry. Hence, a portion of the heat from the burner (which
  was intended to be burning the fuel) was used up in drying the water.
•   No dry grass was used in the dung for burning

•   The flame was not of the same intensity in all experiments

•   There was some amount of loss in the dung quantity as it was shifted from one container
    to the other

•   Due to time restraints, we were not able to wait for the water to cool down after it was
    heated for 90 sec. Instead, we continued the experiment from that temperature.

•   We were not able to account for how much of the temperature rise was caused by the
    bunsen burner. Hence, we do not know what percentage of the heat given out is purely
    from the fuel being burnt.

•   We recorded the temperature of the water rather than the fuel, the values of which are
    bound to be different due to the intermediate space.
• A more accurate result could be achieved by taking a cow that has been
  starved for around 48 hours (thus eliminating the food being digested in
  its stomachs) and then fed the desired diet exclusively for a period of 2-3
• The experiment would be better performed with more sophisticated
  equipment, such as an electronic thermometer which would have a much
  smaller error of uncertainty than a standard thermometer.
• The dung needs to be dried sufficiently, for more accurate readings
• Also, grass should be mixed in with the dung, to make a cake similar to
  what the villagers use
• The dung of a stray cow could have been used, to prove that the
  constituents of the food affects the calorific value of the dung.
• More samples of the dung could have been tested
                Village factsssssss
              Village surveyed: NanaKhaudi (pop. = 1200 houses)

LPG : Rs.400-500 per month (toooo expensive )
Dung and Wood: free 
1 dung cake is enough to heat 2 rotlas
(yummy traditional Gujarati staple bread)
Bio gas: transportation problems (scope here for an energy study
   next time)
Solar Power: people unaware of it / requires a big first time
Dung usage: 200 a month, thus approx. 7 a day
Approx. 2 capfulls of kerosene used to light wood and dung
Image Gallery
Image Gallery
To investigate the viability of the renewable sources - wind and solar power – for
domestic purposes in rural sectors.

Having done no previous experiments in this field we had no previous
experimental data on wind or solar power. Through background knowledge
however, we knew that these two renewable sources are difficult to implement due
to high costs and changing environmental conditions. Because of the problem the
latter creates we realized that we would not get one standard value for any factors
as they all change based on the time of the day, the season of the month, or other
environmental factors. However, having no knowledge on them, we could not
decide which of the two sources would give a greater power value, and hence did
not have a strong hypothesis.
                                   wInD pOwEr

To evaluate the use of wind power in Jamnagar by calculating the efficiency of an average
    wind turbine
We realised that the potential for wind energy existed in Jamnagar but was not being
    utilised. This led us on to think whether it would be feasible to construct wind turbines
    near the jetty where the wind speeds are relatively higher

 Advantages of wind energy:
• No damage is caused to the environment
• It is a renewable source of energy
• After the initial cost, it is a free source of energy

Disadvantages of wind energy
•   There are a lot of fluctuatons in the wind speeds,therefore the energy produced will not be consistent.
•   At night , wind blows from land to sea, therefore energy cannot be harnessed at night
•   There is an initial cost to setup the turbines which is expensive
• Anemometer

• Determine the wind direction.
• Use the anemometer to determine the wind
• Repeat this at different times in the day
            Data for wind velocity for the last one year
            obtained from the reliance control room.

Month            Maximum speed(m/s)          Minimum speed(m/s)         Averag(m/s)

January                               11.7                         0                   0

Febuary                               11.1                         0                   0

March                                 13.1                        1.2                 1.2

April                                 13.5                        2.4                 2.4

May                                   15.0                        4.7                 4.7

June                                  14.3                        1.4                 1.4

July                                  18.8                        1.7                 1.7

August                                17.7                        1.9                 1.9

September                             13.3                        0.2                 0.2

October                               12.7                         0                   0

November                               9.0                        0.5                 0.5

December                               7.0                         0                   0
• Radius of the anemometer was 36 cm.

• Density of air = 0.8 g/cm3 (at 30 )

• The average wind velocity for the whole year =
  8 m/s(±3m/s)
• The power generated per second by a wind
  turbine is given by the formula:
• 0.5 × A × p × v3
• A = area swept by the blades of the turbine
• P = air density
• V=wind velocity (m/s)
• Our data was compared to wind turbines produced by
  companies to help us to calculate the efficiency which
  depends on the model used.
• A wind turbine produced by Suzlon was used to obtain
  a value for the efficiency. However this model may not
  be the most appropriate one for Jamnagar and is used
  as all the details about wind turbines are not available.
• This specific wind turbine has a radius of 32 m and
  covers an area of 3217 m2. Therefore by using the
  formula mentioned above, the power input for this
  model can be calculated if it is to be placed at the jetty.
Power input = 0.5 × A × p ×

= 0.5 × 3217 × 0.8 × 83

= 658840 watt
The following graph shows the power output of
 this model with varying wind velocities:

 From the table it can be seen that the power output for wind with velocity 8m/s
 is 451.62 kW
  Efficiency = (451620 / 658840) × 100 = 68.5 %

• There were a lot of obstructions near the jetty like ships,
  the board of control and pipes which transported the crude
  oil. Due to this, the wind speeds were reduced by a
  considerable amount. Also as the jetty is where the crude
  oil is received, a lot of ships keep coming in to transport the
  crude oil, which reduces the wind velocity.
• Wind turbines are very noisy and this could disturb the
  processes which take place in the jetty.
• The jetty is quite far way from the villages and this could be
  a hindrance.
•    There are three parts to this experiment: finding the input power, finding a suitable
    photovoltaic cell to base a constant output on, and calculating the efficiency
•   To find the input power per m2 we found a tray of whose area we calculated. We then filled
    this tray with 2500ml of water and left it out in the sun to heat for 10 minutes and took
    readings every minute. We repeated this three times which gave us a total of 30 readings
•   Right beside the water tank place the lux meter to measure the light intensity
•   Using a digital thermometer we calculated the temperature change; using all these values
    and the formula for energy (mass x specific heat capacity x change in temperature) and
    dividing it by the time we found the power per m2
•   The standard model of the photovoltaic cell used gave us a maximum value of 120W
•   Using this and our input value calculations we were able to find a value of the efficiency
•   Efficiency = (output / input) x 100

•   Small water tank
•   Digital thermometer
•   Lux meter (light intensity)
•   Stop watch
•   2500 ml of water

Safety Precautions:

• Make sure the lux meter and the water tank receive the same light
• Do not stand close to it as shading the apparatus will reduce the light
                 Solar energy
Data collection:
• We calculated the light intensity at different
• 8 am – 30,000 lux
• 10 am – 50,000 lux
• 2 pm – 70,000 lux
• 1 lux = 1.46 × 10-3 watt/m2
• Therefore 50,000 lux = 730 watt/m2
• 70,000 lux = 1022 watt/m2
• 30,000 lux = 438 watt/m2
• The average value for the power input is 730 watt
• To calculate the efficiency, the specifications of an
  average solar panel can be compared with the
  values calculated by us. (this model used may not
  be the best one to install, and is used to give an
• This solar panel has an area of 1m2 and a
  maximum power output of 120 watt.

Efficiency = (120/ 730) x 100 = 17.8%
Limitations of the experiment:

• First method of using water tank was faulty
• Power output remains constant after a maximum input value for
  the photovoltaic cell is reached; even if the input power value, that
  is as the light intensity increases, the amount the cell can take does
  not increases. This makes the system itself limited.
• As the point where the maximum capacity of the cell is reached is
  not known we can only make an assumption that this will happen at
  a time of high light intensity – we assume this to be
• As we do not know exactly how the mechanism of the solar panel
  works, several things are unclear.
                                      Light intensity vs. time of the day


Light Intensity (Lux)







                            00:00   02:24     04:48       07:12      09:36      12:00   14:24   16:48   19:12

                                                      Time of the Day (24hrs)

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