All posts by bttraore

Solar Enrgy

Solar energy is the energy collected from the Sun’s radiation.  The energy provided by the Sun is comparable to total energy we use worldwide meaning that if we are able to harness this energy we will be able to produce enough energy for the world without any harmful emission (One megawatt hour of solar energy offsets about 0.75 to 1 tonne of CO2). The process of harnessing energy from the sun is done by using Photovoltaics cells (PV) or solar panels.

Photovoltaics (PV) enables us to directly convert sunlight into electricity by converting photons to electricity. Semiconductors materials are combine with the PV to enable the conversion through PV arrays. PV arrays are made of solar cells and come in different sizes and shapes. These PV are made up of a positive and negative Layer which allows to photons to be absorbed, which are used to power an electric device. Here is a video explaining the process:

Sola

 

 

 

 

 

https://joinmosaic.com/what-is-solar-energy/

http://www.seia.org/about/solar-energy

http://www.greenoughsolarfarm.com.au/solar-energy/what-solar-energy

http://pureenergies.com/us/blog/top-10-countries-using-solar-power/

Electricity Production

Electricity is most used form of energy we use nowadays. It is used to lights up our home, cook our food, power our computers, televevison, entertaining centers and other electronic devices. Electricity is made in different ways. Some of these ways are from coal, nuclear reaction and natural gas.

  • ELECTRICITY FROM COAL:

Electricity is made from burning coal. First the coal is ground into powder and put into a boiler where it is burnt at high temperature, this process convert chemical energy into heat energy. The process produce which is then converted into steam. This steam causes the turbine shaft to rotate at high speed. A generator made of carefully wire coils is mounted at one of these turbine to produce electricity.  After passing through the turbine, the steam is condensed and returned to the boiler to be heated once again thus repeating the process. Some of the water is lost during the process.  Here a video explaining the process:

 

  • ELECTRICITY FRO NATURAL GAS

The process of producing of electricity from natural gas is the same as using the coal, the only difference is that to create steam we use natural gas instead of coal. Here is a video explaining the process:

 

  • ELECTRICITY FROM NUCLEAR POWER PLANT

The electricity in this case is not made from burning an element but instead, it is made by using  a process called fission on an uranium fuel which contains solid ceramic pellets. The steam in this case is obtained by a physical process. Fission consist of splitting an atom of uranium. Here are videos explaining Fission and nuclear reactors:

 

 

Nuclear reaction:

 

 

 

 

 

 

 

 

 

 

 

 

http://www.energyquest.ca.gov/story/chapter02.html

http://www.edfenergy.com/energyfuture/coal-generation

http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/

http://www.edfenergy.com/energyfuture/generation-gas

http://www.world-nuclear.org/Nuclear-Basics/How-does-a-nuclear-reactor-make-electricity-/

http://www.nei.org/Knowledge-Center/How-Nuclear-Reactors-Work

Lego Mindstorm Experiment: Work

This lab experiment was to confirm and see how the Work, the Mass ,the Velocity, the Acceleration and the Energy of an object are related to each other and what will happen if they vary.

For accomplish the task at hand we were given a box of masses( these masses were .02Kg each)

IMG_20150206_142331

We then set up the a pulley using Lego-Robot such as:

IMG_20150206_142318

In the program, “http://web.cas.suffolk.edu/faculty/lshatz/Sustainability_class/Labview/Lab2_2.vi“. We first  entered a constant Force and keeping changing the Mass and observed how the acceleration reacts to it.

In the second part, the Mass was kept constant and the Force was changed and the results observed.

There were two was of recording the Data, The first one was to record directly the values from the program after each experiment or to open an excel file were the program automatically saves the values measured. We had to be careful because the excel file is not updated if it is open during the experiment.

End end result was:

Values

 

As a conclusion we can say that, when finding the Work done by an object the Force ( mass and acceleration) is very important. If the force is kept constant and the mass is increase or decrease the acceleration respectively decrease or increase. And if the mass is kept constant and the power is increased or decreased, the acceleration respectively increase or decrease. These three element are related by the formula: Force= Mass * Acceleration.

Frackin- Good or Bad

Fracking, another name of Hydraulic fracturing is a method use to drill wells of natural gases and oil from rock that lies deep under the surface. This has helped change the U.S energy need from a shortage state to an  abundance one.

The process of fracking is by drilling a mile of more below the surface before gradually turning horizontal and continuing several thousand feet or more. This helps access several wells which are sometimes align horizontally. After drilling, the well is cased and cemented. Small perforations are made in the horizontal portion of the well pipe, through which a mixture of water, sand and other chemical is s pumped at a high pressure to fracture the rock and release the oil or gas. The video bellow give a visual explanation of the process:

https://www.youtube.com/watch?v=lB3FOJjpy7s

 

The process is of fracking is problematic for the environment and our life style because it endangers our water and the health or the community. It is to be noted that fracking is exempt from major environmental laws, including the Safe Drinking Water act, and spills and accidents are too common. Some of the dangers of fracking are:

  • The fluids used for the process have not been publish to the public but traces of Formaldehyde, acetic acids, citric acids, boric acids, and in some cases diesel fuel were found on the drilling site. These fluids flow into the earth and may pollute water wells and the ground.
  • The water used in the process called “flowback water” or “produced water”, flows back to the surface. There is no known way to effectively dispose of it. Some of this water is pumped even deeper and according to DR. Bill Chameides of Duke University causes “an earthquake every now and again”.

 

Here is  that will give a summary on the subject and it’s potential risk:

 

 

http://www.what-is-fracking.com/what-is-hydraulic-fracking/

http://www.foodandwaterwatch.org/water/fracking/

http://www.cleanwateraction.org/page/fracking-dangers

http://hightimes.com/read/dangers-fracking

Measuring the error on the Distance using the Lego-car

For this part of the lesson, we run some test and recorded some measurement using the Lego car we built the previous week.

IMG_20150130_134812

 

Using the robot above we entered the value of the wheel diameter, the time during which the car should move (in second) and the power of each wheel in a program called ” wheel_rotation_straight.vi

IMG_20150130_134816

We then choose 3 different time and power and for each of this values, we run 3 test and recorded the value. We recorded the distance (in centimeters) from the starting point to the stop point and calculated the error using the distance value showed on the program.IMG_20150130_134829

 

We then made the following table:

Power Time (s) Distance measured (m) Distance Labview (m) velocity Labview (m/s) Velocity measured(m/s) Error% Distance
30 3 0.32 0.3 0.101 0.106666667 6.451612903
0.307 0.303 0.101 0.102333333 1.31147541
0.306 0.3 0.1 0.102 1.98019802
50 3 0.552 0.5409 0.1802 0.184 2.03129289
0.552 0.537 0.179 0.184 2.754820937
0.545 0.527 0.175 0.181666667 3.358208955
75 3 0.551 0.538 0.269 0.183666667 2.387511478
0.552 0.536 0.268 0.184 2.941176471
0.545 0.537 0.268 0.181666667 1.478743068

 

The table can be downloaded using this link: “labview for sci184 without velocity

 

Energy Grid

Energy Grid also known as grid energy storage is the set of methods used to store electricity on a large scale and distribute it to power companies.

grid display

The above image gives an idea of how the system works. The system is made of a power station where the electricity is produced and stored, power transformers that step down the voltage so that it will be able to travel through the electric cables. Depending on where the power is going to be used (commercial & industrial or residential consumers), the distributor might need the step down the voltage even more because too much voltage can cause a defect of devices or death.

One of the downside of conventional Energy Grid is that the distributors has to assume what the consumer consumption will be for the next day by analyzing previous data making it the method unreliable if the number of customer is by millions. One way to solve this problem is by making Smart Grid which basic idea is to set up a two way system between the distributor and the customer letting the distributor know exactly when the customer energy need are increasing and also increase the output.

Smart Grid have many more advantage. Some of them are listed in the video bellow:

 

 

 

 

 

 

Sources:

http://www.altenergymag.com/emagazine.php?issue_number=09.04.01&article=smartgrid

http://www.bloomberg.com/bw/articles/2013-08-22/homegrown-green-energy-is-making-power-utilities-irrelevant

https://www.smartgrid.gov/the_smart_grid/smart_grid