Muath Alqurashi

On Thursday, December 6, 2012, Michel, Fatumata and I want to O’Bryant High School in Roxbury to present an experiment we had been working on. In this experiment, we used lemons to generate electricity. The main goal of the experiment was to show the students how can we use clean and renewable energy sources to generate electricity.

The Experiment:

For this experiment you’ll need:

1- Two fresh lemons.

2- Two Pieces of Copper.

3- Two Pieces of Aluminum.

4- Two Wires.

5- Small battery-operated clock.

All you have to do is the following:

1- Gently squeeze each lemon without breaking the skin of the lemon in order to soften the lemons which would allow for internal release of more citric acid

2- Insert into each lemon a small piece of both metals being used. In this case insert a small piece of aluminum and copper into different areas of the lemon as to prevent them from touching.

3- Connect the aluminum from lemon 1 to the copper of lemon 2, then connect the aluminum from lemon 2 to the negative wire of the clock. Finally, connect the copper form lemon 1 to the positive wire of the clock.

When you do that, you should get the clock up and running.

What Happen? 

At the aluminum end, the aluminum is oxidized (or more commonly; “rusted”) by the acid in the lemon which creates a bunch of negatively charged electrons. Those electrons really want to zip over to the copper to balance things out, but they cannot flow through the lemon. Only when the aluminum is connected to the copper by a wire will the electrons be able to move across. Along the way they will provide electricity to the clock in its path.

Note: you can get approximately 0.6 Volts from each lemon. Also, if you connect two lemons in series, you can get 1.2 Volts.

Application:

“Malaysian scientists use tropical fruits to make batteries. They have discovered that bamboo, coconut shells and durian fruit skins can be converted into an activated form of carbon used to make the components of electric batteries known as ‘supercapacitors’.

Activated carbon is normally made from coal but now researchers say it could be sourced from a natural, renewable source, providing income to rural people.” (http://www.scidev.net).

In conclusion, using lemons to generate electricity was a fun experience for all of us. We also had fun explaining it to the students in O’Bryant High School.

In the hot days of summer, everybody turn on their air conditioner consuming massive amount of energy at the same time. This kind of usage puts the entire grid under the possibility of power outage. The reason behind black outs is that the demand of electricity exceeds the supply.

This graph illustrates the demand of electricity. When it is a really hot summer day, the utility won’t be able to meat the demand. They have three choices; operate extra power plants, buy electricity from another region, or demand response programs.

The first option, operating extra power plants, is not a great choice for many reasons; it is expensive, emits more CO2, and the technology at these power plants are outdated.

Purchasing electricity from another region increases the rates. It also creates tons of waste.

The third option, demand response programs, are the best solution to this problem. Participants in this program get a call from the electric supplier asking them lower their usage of electricity during peak demand events. After peak demand events, participants are allowed to turn back to their normal usage of electricity. For example, if the utility supplier expects a hot day tomorrow, it contacts some of its participants asking them to cool their rooms today prior to an expected peak demand event.

This method saves a lot of money and energy, and provide more stable electricity.

Sources:

http://www.youtube.com/watch?v=weNGPtx1StA

http://en.wikipedia.org/wiki/Demand_response

http://www.mpoweruk.com/electricity_demand.htm

Energy cannot be created or destroyed, only converted from one form to another.

One of the renewable energy sources we can convert to electrical energy is the solar energy. We convert the solar energy using a solar cell. When the sunlight hits the solar cell, the photons induce electrons to flow creating electrical energy.

In the lab, we did some experiment with this phenomenon. We were given a solar cell, a light source,three different frequency filters, a ruler, and a voltmeter that is connected to the computer.

There are two factors that affect the voltage generated by the solar cell, the distance between the cell and the light source, and the frequency of the light. The purpose of this lab was to observe these factors.

Distance vs. Voltage:

At the beginning, we measured the average voltage with no lights at all. Then, we put the light source right against the solar cell to get the maximum voltage. After that, we increased the distance between the light source and the cell to 10 cm. We recorded the voltage generated at that distance. Then, we increased the distance again to 20 cm and recorded the voltage.

The following table shows the relation between the distance and the voltage generated.

No light ………. 0.108478 V

Max light ……. 0.429228 V

10 cm ……… 0.243193 V

20 cm ……… 0.195722 V

From the table, the voltage is inversely proportional to the distance. That means, when we increased the distance, the voltage decreased.

Frequency vs. Voltage:

The other factor we observed was that different frequencies from the light affect the voltage converted by the cell.

We were given three different colored filters, purple, pink, and yellow. These filters allow specific frequency to go throw and block the others.

The following table shows the voltage generated when a filter is applied.

Purple ….. 0.252174 V

Pink ….. 0.304777 V

Yellow ….. 0.368927 V

No filter ….. 0.429228 V

From the table, the most voltage generated is when no filter is applied. The second most voltage generated is with the yellow filter. The third would be when the pink filter is applied. Lastly, the purple. It seems that the purple filter blocks a great amount of frequency.

The factors affecting the voltage generated by the cell are not limited to the above, but that was what we observed in the lab.

On Thursday, October 18, 2012, we were given a simple electrical generator that converts motion into electricity, a voltmeter, and a device that connects the voltmeter to the computer. The electrical generator is consisted of a non-movable ring of coil and a movable magnet that passes through the coil. Both of these components are contained in a cylindrical shaped plastic container.  When shaking the plastic container, the magnet passes through the coil generating electrical voltage. Both ends of the coil are connected to the voltmeter and the voltmeter is connected to the computer through a device.

The purpose of the experiment was to see the relation between the number of shakes and the voltage generated. So, we had to shake the generator for 30 seconds and counted the number of shakes. In the mean while, the computer took a reading from the voltmeter every second, then output the results to an Excel file.

We shaked the generator three times at different number of shakes. The following table shows the relation between the number of shakes and the total voltage generated.

0 shakes …….. 0.180625861 V

29 shakes ……….. 0.37242538 V

68 shakes …………. 75.32163037 V

As you can see from the table, the number of shakes is directly proportional to the voltage generated. That means, increasing the number of shakes increases the voltage.

Energy cannot be created or destroyed, only converted from one form to another. We needed energy to shake the generator, that energy got converted to electrical energy. That is the dilemma the world is facing. We need renewable energy sources so we can convert it to electrical energy.

Fukushima Daiichi is a Japanese term referring to a nuclear power plant. Fukushima is the name of the prefecture where the plant is located, and Daiichi means number one. Fukushima’s prefector is located on the northeaster cost of Japan. (See the map).

Fkushima Daiichi is one of the world’s largest nuclear power plant. It was started on 1971. Now, the capacity of this plant is 1,933 MW.

Huge Disaster:

Fukushima Daiichi nuclear power plant has 6 units of operation, and the japanese were planning to build two more but a huge disaster occurred.

On March 11, 2011, 02:45 PM  Japan Standard Time (GMT +09:00), an earthquake categorised as 9.0 MW stroke the northeastern coast of Japan where the nuclear plant is located. Before the earthquake happened, unites 4, 5, and 6 were out of service due to a regular maintenance. Unites 1, 2, and 3, however, were up an running. When the earthquake happened, units 1-3 where automatically shut-down and the fuel was being cooled down by the emergency generators which was designed for such accident. Every thing was running smoothly till the follow-up tsunami stroke the entire plant. The waves of the tsunami were about 14 meters high casing the cooling generators to stop. That led the reactors to overheat, then meltdown. The meltdown has caused a huge explosion which released a significant amount of radiation from the units exploded. The explosion spread a considerable amount of smoke and the government has evacuated the near by area. They evacuated residents who lives within 30-kilometer from the plant.

As of April 20, 2012, all the units where shutdown except for unites 5 and 6 because they were not running on the day of the disaster. They were under regular maintenance.

Due to this accidents, governments such as Germany has taken steps towards safe renewable energy. The question is, will they succeed and lead the entire globe to take the same step?

Sources:

http://en.wikipedia.org/wiki/List_of_nuclear_power_stations

http://www.noypi.ph/index.php/nation/3295-government-scientists-on-japan-nuke-meltdown-no-need-to-worry.html

http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant

Gas mileage is one of the most important features customers ask about when buying a car. It tells them how much gasoline does a car consume per mile. The unite of measure is Miles per gallon (MPG). According to Wikipedia, (MPG) means “the measures of fuel economy in automobiles, that is, how many miles a vehicle can travel on one gallon of fuel,”.

Driving fast, and loading your car can decrease your gas mileage. When you drive fast, your car consumes more energy because of the air resistance. And when you load your car, you consume energy. The energy required to move a not-loaded car is less than moving a loaded car. Auto manufacturers knew this fact and decreased some of the car’s weight by using  lighter materials for moving parts such as pistons, crankshaft, gears and alloy wheels.

There are many types of car that helps increasing gas mileage. For example, hybrids, electric vehicles (EV) and flex-fuel vehicles. These cars have a great gas mileage because they don’t mainly consume gasoline.

Hybrids:

Hybrid cars get the best of both electric and gasoline engines. They are combined to improve fuel economy, increase the power and many other things.

Technologies:

1- Regenerative Braking: The electric motor applies force into the braking system casing the wheels to slow down. Also, the energy from the wheels are preserved in the battery. The wheels turn the the motor which function as a generator preserving the wasted energy in the battery.

2- Electric Motor Drive/Assist: the electric motor supply extra power helping the engine in accelerating, passing, or hill climbing. Some cars uses the electric motor in slow speeding cases because it is more efficient than the internal combustion engines.

3- Automatic Start/Shutoff: the motor shuts off automatically when the car stops completely. And it starts again when the accelerator is pressed. This helps preventing wasted energy.

Electric Vehicles:

These type of cars move by an electric motor. They get the energy form a rechargeable battery packs.

Advantages:

Energy efficient:

EVs convert about 59–62% of the electrical energy from the grid to power at the wheels .

Environmentally friendly:

EVs does not produce any type of gas. However, the power plant providing the electricity may produce them.

Performance benefits:

These type of cars have silent and smooth operation. They do not require much maintenance and they have a powerful acceleration.

Flex-Fuel Vehicles:

Flexible fuel vehicles are made to function on either gasoline or a mix of about 85% ehtanol (E85). They are exactly the same as gasoline-only cars except for some fuel system differences. FFVs has also the same performance as the regular cars when it is filled with (E85). FFV’s gas mileage is less 25-30% than a regular car’s gas mileage because ethanol has less energy per volume than gasoline.

This type of cars have been around since the 80’s and they are available now in great numbers. They look so much like the regular cars. You might be driving one.

If you see one of the following images on a car, then know that this car run on ethanol.

These vehicles represent the most important ways auto industry use to increase gas mileage. I hope it was informative.

Sources:

http://www.fueleconomy.gov/feg/hybridtech.shtml

http://www.fueleconomy.gov/feg/hybridtech.shtml

http://www.fueleconomy.gov/feg/evtech.shtml

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles#cite_note-15

On Thursday, September 20, 2012, we were given an unassembled robotic car to do an experiment with it. The objectives of the experiment were to assemble the car, program it to run for a short period of time, and study the results of that command. It took most of us two class periods to achieve these objectives. Each period was seventy-five minutes. In the first period, we assembled the car. In the second one, we did the rest of the objectives.

Assembling the car was the most time-consuming task, not because it was difficult, but because it was my first time building such a car. When my partner and I, with some help from another student, finished building the car, we discovered that the the wheels were not in place properly. So, we had to spend some extra time fixing that. After assembling the car, we made a small test just to make sure that the car ran properly. It did ran properly.

Programming the car did not require as much time as assembling it. Though, we had to do some mathematical calculations in order to program it.

How Does the Car Work and How is it Programmed?

Users give instructions to the car through a program called Labviwe. The car is connected to the computer using a USB cable so all the instructions are transferred to the car via the cable. Although we had the instructions ready, we had to specify them with some numbers such as the duration we want it travel for, the circumference of the wheels, and the how fast we want it to move. When we specify that, we run the car. Once the car stops, Labviwe will output the distance the car traveled with some other information. We were to measure the actual distance it traveled and compare that with Labview’s output to see how accurate is the program.

Calculations:

Distance is measured by the number of turns the wheels make. That means, one turn = the circumference of the wheel * 1, two turns equal the circumference * 2 and so on. The calculation we had to make in order to program the car was to find the circumference of the wheels. That can be found by measuring the diameter of the wheels then plug it in the following equation:

C = circumference.

R = Radius = diameter/2.

The circumference of the car’s wheel was 15.71 cm. But since the program requires all measures to be in meters, we had to convert this number into meters which equals 0.1571 m.

Accuracy:

The accuracy of the program can be determined by the following formula:

We made several trials to see what is the percentage error of the program.

Trials:

Trial 1:

Actual distance = 62 cm = .62 m

Program’s output = .53 m

Percent Error = 14%

Trial 2:

Actual distance = 42 cm = .42 m

Program’s output = .24 m

Percent Error = 75%

In this trial we changed the power from 75 to 50. Maybe that is why the percent error is high.

Trial 3:

Actual distance = 45 cm = .45 m

Program’s output = .31 m

Percent Error = 31%

In this one, we increased the power 50 to 60

The average percent error = 40%

I really had fun building and programming the car. I had gain some experience in building such cars.

In 2000, Germany has forced a law that encourages and promotes the use of renewable energy sources. “This act enables any company or individual who meets the technical and legal requirements to sell renewable electricity into the power grid for a guaranteed, long-term price for each kilowatt-hour sold.” (worldwatch.org).

Current Status:

Wind turbines, hydroelectric plants, solar cells, and biogas digesters cover about 17% of the electricity in Germany. The German Ministry for the Environment and Reactor Safety states that these renewable sources has generated 100 TWh in 2010.

The following table shows how much does every source – conventional and renewable – generates in Germany.

Goals For the Future:

Germany’s government does not stop at that far. They have grater goals to achieve in the field of energy.

By the end of this decade, Germans target to increase the renewable share in total heat supply to 14%, and to 10% in final energy consumption in the transport sector.

“These targets will also help to lower greenhouse gas emissions in Germany by 40 percent by 2020 and by 80 to 95 percent by 2050 (compared to 1990). To this end, the government aims to reduce electricity consumption by 10 percent by 2020 and by 25 percent by 2050, while primary energy consumption is to fall by 20 percent by 2020 and 50 percent by 2050.” (Renewable Energy Sources in Figures 9).

Sources:

http://www.erneuerbare-energien.de/files/english/pdf/application/pdf/broschuere_ee_zahlen_en_bf.pdf

http://www.renewableenergyworld.com/rea/news/article/2011/03/new-record-for-german-renewable-energy-in-2010??cmpid=WNL-Wednesday-March30-2011

http://www.worldwatch.org/node/5430

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