Monthly Archives: March 2016

MOS Trip

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Introduction

Last Friday, my classmates and I had a chance to visit Museum of Science in Boston, where we did not go any time in 5 years since I came here. It is big and wonderful place where you should bring your kids and lead them learn more about science. The design of museum is suitable for kids because it does not look fancy as any art museums. Even though I am a college student, I am still bewitched by everything at this place. The professor asked us to visit Energized!, Catching the Wind, Conserve@Home, and Investigate because those places are relate to what we have learned in class. I looked at all of this, but there were so many kids so I could not have experience with some technologies. Nevertheless, there are three interesting places as three topics that I want to discuss about in this blog.

 

Catching The Wind Exhibit

 

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This exhibit focuses about wind energy and how it works. On the wall, there are so many information about power of the wind, turning wind into electricity or wind power in Massachusetts. Also, learned where the wind come from and how it measure by pictures and information on the wall. Wind id a form of solar energy when sunlight hitting the Earth heats the air unevenly. Moreover, wind power is measured in units called kilowatts (kW) which equal to one thousand watts, or in megawatts (mW) which equal to one million watts. It is measured by the total energy generated for one hour, as in a kilowatt-hour (kWh), or megawatts-hour (mWh). Also, I saw how a turbine is built a specific information and images. The picture below shows different parts of a turbine and their own job in producing wind power.

 

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Make Choices About Energy Source

 

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It takes a mix of energy sources to power our city, and each source has advantages and drawbacks. This place is where I could measure how much energy supplied and impact on environment. It is fun and easy experiment where I only need to mix any energy sources that I want and see how it can light up the skyline above. There are 4 steps:

  • I place a puck down a slot to make an energy choice.
  • Check the meters to see the effects of my choices.
  • Experiment with different energy combinations
  • Then, find an energy mix that makes the skyline above light up

Because I did not look at the guideline at the beginning so I only did a test on fossil fuels. I tool three bucks and the result was above the average. It means that fossil fuels has a high major contributor to air pollution and environmental impact. The picture below shows the similarities and differences of fossil fuels, hydropower, nuclear, solar, and wind which are based on 5 main factors: time to replenish, cost, amount of energy available, environment impacts, and limits. It is a great model for kids to learn how energy sources affect on environment, and know how to manage usage in their life.

 

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Solar Collector

Solar collector is a model showing how we use solar to produce energy. As what you can see in a video above, I was testing to see how gears could run when a mirror getting a light. There is a light on the top and three mirrors on a table which I could use my hand to control them. Also, there is a small mirror on the top of a gear machine which is used to collect light from opposite mirrors. When I move the big mirror, a small light will appear. Then, I moved the big mirror until the light is on the small mirror. Finally, gear machine would start to run. When I moved the light away, it will stop. It is interesting that I could experience with what I learned in class to understand deeply how the energy is produced by solar.

 

 

Outside the Course

 

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There is one thing that I was excited to see even though it does not relate to this course. It is dinosaur. Since I was born, I did not have any chance to see the real bonds of dinosaurs. Before the trip, I spent a little bit time to search about this museum, and I was really excited when I saw the bonds of dinosaurs in the review pictures. I learned about many different kind of dinosaurs such as Triceratops, Tyrannosaurs rex, or its footprint. Also, there is a picture that shows grouping of dinosaurs by shared traits. I am always curious about natural world and what happens around us. In some day, I will come back to Washington DC to visit the National Museum of Natural History.

 

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Conclusion

I am thankful with my professor who gave me a chance to explore what I did not know in science field. It was a wonderful experience that I will never forget in my life. Even though I am not good at science at all, I still want to learn more about natural history and space. It will be easy to understand a lesson if you have a chance to experience with it in your real life. Hopefully, when my have kids, I can bring them there and tell them what I learned in the past.

 

Pandora’s Promise Movie Reaction

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Background

Pandora’s Promise is a 87 minutes documentary film about nuclear power debate,  directed by Robert Stone. The central argument is that nuclear power, an energy source which still faces historical opposition from environmentalists, is a relatively safe and clean source which can help mitigate the serious problem of anthropogenic global warming. This movie includes those peoples whom were  once vehemently opposed to nuclear power but who now speak in favor of it,  Stewart Brand, Gwyneth Cravens, Mark Lynas, Richard Rhodes and Michael Shellenberger. They talked about nuclear disasters in the past and how they changed their mind through this 87 minutes film. Also, the total money was raised to finance this movie is $1.2 million (US).

This video below is an official trailer of Pandora’s Promise movie which shows a general idea about what would happen in this movie.

 

 

Is nuclear power safe? 

The answer is yes. Base on the evidence over six decades shows that nuclear power is a safe means of generating electricity. The risk of accidents in nuclear power plants is low and declining. Moreover, the radiological effects on people of any radioactive releases can be avoided. According to Gwyneth Cravens’s speech in this film, she mentions that, “Physician and anti-nuclear activist Helen Caldicott…calling the nuclear industry a ‘death industry’ and claiming that facilities from the 1986 Chernobyl nuclear plant disaster were upward of 1 million people. But several others in film, put the number at only around 50, or if you count some sick people who haven’t yet died, in the low thousands.” It means, the radiation did not affect dangerously to human lives as what we had seen on the news. Because of social media, we created an antipathy to this energy source without understand clearly about how it works and impacts. Also, there has not been a single death from operation of commercial nuclear reactors in the United States.

Nuclear power is greener and safer than coal. According to the information in this film, coal can kill 13,000 people every year in the United States with a few add up all fossil fuel combination. Peoples keep using coal in producing while they avoid nuclear power just because of the exposing of three nuclear power plants. They do not know that it would kill people.

 

Conclusion

After watching this documentary film, there are too much information in this movie and it made me confuse a little bit, and I could not get the main point in the first seen. However, everything is good and organized. Also, I have learned that no energy sources can be replace by another such as solar and nuclear power. We cannot replace nuclear power by solar. They have their own job to provide energy for human lives. Solar is not nuclear. You cannot turn on Sun in the winter to heat up your house. Instead of avoiding and looking for the other safe energy source, we should learn how to deal with the danger around us. As you can see, the picture below shows that if we take away nuclear power, the our planet is going to lose its balance.

 

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Reference

http://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx

https://en.wikipedia.org/wiki/Pandora%27s_Promise

https://www.youtube.com/watch?v=bDw3ET3zqxk

Nuclear Disasters

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Background

Nuclear disaster, as known as nuclear and radiation accident, is defined by the International Atomic Energy Agency as an event that has led to the significant consequences to human, environment or the facility. The impact of nuclear disasters has been a topic of debate since the first nuclear reactors which were constructed in 1954. Also, it became a key factor in public concern about nuclear facilities. There have been 99 accidents at nuclear power plants around the world. There were fifty-seven accidents have occurred since the Chernobyl disaster, and 57% of all nuclear related accidents have occurred in the United States. In this blog, I will discuss about two nuclear disasters: Chernobyl disaster (1986) and Fukushima disaster (2011)

Chernobyl Disaster (1986)

 

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Chernobyl Nuclear Power Plant locates in a town of Pripyat in  Ukraine, which was uder the direct jurisdiction of the central authorities of the Soviet Union. The picture above shows the power plant after the nuclear disaster in 1986.

 

What Happened and Why?

On April 26, 1986, a major accident occurred at Unite 4 of the nuclear power plant at Chernobyl, Ukraine, in the former USSR. The accident and the fire followed released massive amount of the radioactive material into the environment. While conduct the test, the reactor had to be powered down to 25% of its capacity. However, the procedure did not go according plan and the reactor power level fell to less than 1%. After 30 second, there was an unexpected power surge, and the reactor’s emergency shutdown failed. Because of the failure, there was a violent explosion which made the 1000-tonne sealing cap on the reactor building blowing off. Also, the fuel rods melted at the temperature over 2000°C. The graphite burned for nine days, churning a big quantities of radiation into the environment.

After the accident, officials closed off the area within 18 miles from the plant. There were 28 out of 600 workers were killed by the radiation effects in the first four months after the event. Also, there were 2 workers died within hours of the explosion from non-radiological cause.  The Soviet government evacuated about 115,000 people from the most heavily areas in 1986, and the other 220,000 people in subsequent years.

 

Fukushima Daiichi Disaster (2011)

 

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Fukushima Daiichi Nuclear Power Plant is located in Fukushima Prefecture, Japan. This station was operated by Tokyo Electric Power Company. The picture above shows the explosion in 2011

 

What Happened and Why?

On March 11, 2011, there was a larger earthquake and a 15-metre tsunami disabled the power supply and cooling of three Fukushima reactors which causes a nuclear accident. The accident was rated 7 on the International Nuclear Event (INES) Scale. Also, there were four reactors that were written off due the damage in the accident. After two weeks, the three reactors (units 1-3) were stable with water addition and they were being cooled by the recycled water for the new treatment plant. Nobody are killed or get sick from the nuclear accident, but over 100,000 people had to be evacuated from their homes to ensure this. Unfortunately, the official figures show that there have been well over 1000 deaths from the maintaining the evacuation.

 

Safety of Nuclear Power Reactors

In my opinion, we should have a stronger system to reduce the percentage of accident in the lowest rate. Also, we should build a strong power plant with an thick iron wall. Moreover, we should know how to face with the nuclear waste. It is hard to tell in a specific way because it is really hard to control a nuclear accident. It affects dangerously into human health. Otherwise, we can develop the clothes of workers in power plants station to help them reduce the danger from nuclear effects.

 

Conclusion

The two disasters in Chernobyl and Fukushima left a dangerous effect on human health and environment. The nuclear go to food, vegetable, and water. It impacts on human life hardly. Hopefully, we will have some strong power plants that can never be destroyed.

 

 

 

Geothermal Energy in Iceland

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Background

Iceland is a Nordic island country between the North Atlantic and the Arctic Ocean. This country has a special geological location with the high concentration of volcanoes. Also, the high concentration of volcanoes can be an advantage in the generation of geothermal energy, the heating and production of electricity. Iceland is a pioneer in the use of geothermal energy for space heating.

 

Geothermal Energy

Geothermal energy is the thermal energy generated and stored in the Earth. It is the energy that determines the temperature of matter. There are current 6 geothermal power plants in Iceland, and they are Hellisheiði Power Station, Nesjavellir Geothermal Power Station, Reykjanes Power Station, Svartsengi Power Station, Krafla Power Station, Bjarnarflag Power Station. Six geothermal major power plants exist Iceland and produced approximately 26.2% of the nation electricity in 2010. Hellisheiði Power Station is the third largest geothermal power station in the world. This station has a capacity of 303 MW of electricity and 400 MW of hot water. Nesjavellir Geothermal Power Station is the second largest geothermal station in Iceland which produced approximately 120 MW of electrical power 1,100 litres of hot water. As same as, the Reykjanes Power Station can produced 100 MW; Svartsengi Power Station produced 76.5 MW; Krafla Power Station produce 60 MW; and Bjarnarflag Power Station produced 3 MW.

 

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How is geothermal energy used in Iceland?

Fish Farming

Fish Farming in Iceland was mainly practised in shore-based plants. Usually, geothermal water is about at 20-50°C which is used to heat the fresh water in heat exchangers from 5 to 12°C. It requires a large consumption of both freshwater and seawater and it is expensive. However, this process is still commonly used.  The electrical consumption is reduced by injecting pure oxygen into the water. Overall, he total geothermal energy used in Iceland’s fish-farming sector is estimated to be 1,600 TJ per year and this project is expected to increase in the future.

 

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Bathing and Recreation

In Iceland, there are 169 recreational swimming centers and 138 of them are using geothermal heat. Based on the surface area, 90% of the pools are heated by geothermal sources, 8% by electricity, and 2% by burning oil and waste. For he geothermal heated swimming pools, there are 108 are public and 30 are located in schools. Swimming is very popular in Iceland so the number of pools is increasing by year. There are 17 public pools in Reykjavik area. Also, the largest pools is Laugardalslaug with a surface area of 2,750 m2 plus eight hot tubs. Usually, we need 220 m3 of water or 40,000 MJ of energy to heat up one m2 pool surface. It means if we want to heat up a pool, we have to use as much as hot water is need to heat about 80-100 single-family dwellings. The total annual water consumption of geothermally heated swimming pools in Iceland is estimated to be 6,9  million m3, which means we have to use 1,300 TJ per year.

 

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Conclusion

Icelanders are smart in using natural resources to produce energy and power. This country has many volcanoes but it does not mean that we cannot do anything with them. We can use the advantage of geography to earn benefit by building some wonderful project as what Iceland had done. Hopefully, these projects can be more successful in the future and we can apply them worldwide.

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Reference:

http://www.nea.is/geothermal/direct-utilization/fish-farming/

http://www.nea.is/geothermal/direct-utilization/bathing–recreation/

https://en.wikipedia.org/wiki/Geothermal_power_in_Iceland

 

 

Thermoelectric Devices

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Background

Thermoelectric device is made from thermoelectric modules. It creates voltage by the temperature of each side of the devices. One of the common device of thermoelectric is thermoelectric generator. Thermoelectric generation, as known as TEG, is a solid state device that can convert heat into electrical energy through a a form of thermoelectric effect called  the Seebeck effect. A thermoelectric generator is made of many pairs of p-type and n-type elements. The p-type elements are made of semiconductor materials which are positive (holes) and Seebeck coefficient is positive. The n-type elements are made of semiconductor material doped which are negative (electrons) and the Seebeck coefficient is negative. Also, it works without any need for moving parts like turbines.

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How do thermoelectric generators work?

  • Connect the p-type and n-type elements to create a voltage potential.
  • When the p-type and n-type elements are connected electrically, mobile holes in the p-type element will see the mobile electrons in the n-type element and migrate to the other side of the junction.
  • For every hole that p-type element migrate into n-type element, an electron from the n-type element will migrate into the p-type element
  • The mobile holes in the p-type and n-type elements are excited by the heat and move further into the element with the extra kinetic energy. Also, many of the holes pile up at the cold end of the p-type element and many of the electrons pile up at the cold end of the n-type element, thereby creating a voltage potential across the p-n junction.

 

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  • If you add a voltage potential from the cold end of the p-type element to the n-type element, the electrons from the n-type element will see all of the holes piled up at the end of the p-type element and hitch a ride along the wire into the p-type material.

 

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  • Then, a hole from the p-type element will see a vacancy in the n-type element and migrate in that direction
  • The end effect is current flow across a voltage potential from p-n junction, and electrical power is created.

 

Uses of thermoelectric devices

Thermoelectric devices are used for a large mechanical generation as a cooling unit. The BMW Group decided to develop a prototype vehicle with a thermoelectric generator  to investigate the interactions of this technology with the power train. BMW X6 is the newest model using thermoelectric device as cooling unit inside the vehicle. It allows a smaller alternator to reduce the roll friction, leading to an increase in fuel efficiency and reduced CO2 emissions.

 

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The second cool application for thermoelectric device is BioLite Kettlecharge. As how thermoelectric generator work, BioLite Kettlecharge use heat and cool water to provide the power for the charger. It can recharges smartphones, camp lights, GPS and the other USB devices by using 10  watt through USB. In the video below, the advertisement shows how handy this product is when our home has no electrical power or we are in the forest. We can use this product easily by using heat and water only.

 

 

Conclusion

Thermoelectric generators do a great job in providing power in this electrical generation. In the future, there will be more inventions using thermoelectric generators to convert temperature to energy. Hopefully, these products can also help to reduce the carbon dioxide and pollution in the future.

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Reference:

https://youtu.be/KJDX9TPImiA

http://www.marlow.com/resources/general-faq/7-how-do-thermoelectric-generators-tegs-work.html

http://www.crookedbrains.net/2015/08/essential-thermoelectric-generators.html