Museum of Science

As part of our class, we visited Boston’s museum of science in order to see some of the things we have been learning about in action. We collected information about various exhibits and spent the afternoon looking at related topics.

The first exhibit that was related to our syllabus was the “Catching Wind” exhibit about the use of wind energy and its productivity in the New England area. The exhibit first gives a quick introduction about how wind occurs in the first place (warm air rising and cold air moving to fill the space) and how the wind energy is measured (kilowatts).  The next section of the exhibit breaks down the parts of the turbine and how they actually produce energy when moved by the wind. It also shows a map of Massachusetts and where the wind turbines are located (there are only a few) due to the fact there are few open spaces large enough to house these turbines. The last panel in the exhibit gives pictures of each different kind of wind turbine and how much energy each prospective device generates. Some very clearly produce more than others but are also much larger and require higher wind power to use them.

 

The next exhibit that we viewed was titled “conserve at home” and was designed to teach the average consumer ways to save electricity and energy in and around their homes. One specific part of the exhibit explored the different lightbulbs options that people use within their homes and how much energy required to power each one. It required the participant to crank a generator until the lightbulb was powered on thus demonstrating which lightbulbs required more energy than others for the same amount of illumination. It concluded that LED lightbulbs only need 8 watts of energy, CFL lightbulbs only need 9 watts of energy, while incandescent lightbulbs need 40 watts of energy to produce the same 450 lumens. I liked this exhibit because you could clearly see how much more energy certain lightbulbs required over others when you had to power the generator yourselves.

 

Although we have been learning about solar energy through phovoltaics I found one exhibit interesting that explored the other ways we can harness solar energy. Solar collectors use mirrors to reflect all sunlight into one central point which generates enough heat to boil water and use the steam in the same way a coal or petroleum plant would. According to the exhibit, there are three collection methods: towers, troughs, and parabolic dishes.

Below is an example of how the sunlight is reflected to heat the water.

 

The last exhibit we saw that related to class was titled “Investigate!”. It featured many things relating to our everyday lives and demonstrated many things that you possibly knew about but never understood. For example, one of the parts of the exhibit explored why some foods grow mold quicker and greater than others? Another part of the exhibit (which unfortunately wasn’t up and running) was to investigate if styrofoam cups really your drinks hotter longer? My favorite part of the exhibit however was to investigate what happens when you put various objects in the microwave. I was already aware of what happens which you put marshmallows in the microwave since I have previously done it but what surprised me was what happens when you put soap in the microwave (a similar reaction) and when you put a lightbulb in the microwave (a subsequent energy surge).

 

This is what happens when you put soap in the microwave for all who wondered as well:

Nuclear Energy

Although nuclear energy has come a long way since it was first developed, the technologies we use are still never 100%. We have experienced multiple nuclear disasters in past decades and although some have been minor accidents others have been detrimental to the environment and the communities surrounding the affected areas.

The largest nuclear disaster in history was undoubtably Chernobyl in 1986. The meltdown was caused by plant operator error combined with a flaw in the design of the reactor. The meltdown was caused by an unexpected power surge, and when an emergency shutdown was attempted, an exponentially larger spike in power output occurred, which led to a reactor vessel rupture and a series of steam explosions. Eventually the reactor ignited when exposed to stored chemicals causing radioactive material to be expelled into the air.

The accident destroyed the Chernobyl 4 reactor, killing 30 operators and firemen within three months. One person was killed immediately and a second died in hospital soon after as a result of injuries received. Acute radiation syndrome (ARS) was originally diagnosed in 237 people on-site and involved with the clean-up and it was later confirmed in 134 cases. Of these, 28 people died as a result of ARS within a few weeks of the accident.

The explosion contaminated thousands of square miles reaching all the way from Russia to Belarus.

 

The second largest nuclear disaster in history happened in 2011 in Fukushima, Japan. The disaster was caused by a massive earthquake of magnitude 9.0 on March 11th 2011.  In Fukushima, when the victims had been working on cleaning up their surroundings after the earthquake and tsunami, a large explosion occurred at the Fukushima Daiichi nuclear power plant and the piping facility in the building, the facilities for the external power supply and backup power were destroyed. The next day, 12th in the early morning, the leakage of radioactive materials had been found in front of the main gate of the nuclear power plant. The steam was filled in the building by the core melt down caused by the dysfunction of the cooling system.

Lots of radioactive materials were scattered in the environment to reduce the internal pressure and the hydroponic explosions of the nuclear reactors. Based on the data from TEPCO, the amount of radioactive materials released into the air were 770,000 tera Bq until beginning of Apr.11,2011, and still going on with high risk. It is said that this amount is about 20% of the Chernobyl accident. On April 12th, 2011, Nuclear and Industrial Safety Agency raised the rate of the accident from level 5 to the level 7, the same level as Chernobyl.

The Map below shows the spread of the nuclear waste according to wind patterns and ocean currents.

The real question is: how can we make this growing energy source safer? There are clearly very dangerous repercussions if this energy is not managed correctly and many people are in favor of outlawing it entirely. There are many risk factors associated with nuclear energy use such as waste disposal and proper protection from radiation.

According to the International Atomic Energy Agency (IAEA), a nuclear security plan can be achieved through “prevention, detection of and response to malicious acts, and Information coordination and analysis.” There are very imporant aspects to consider when choosing nuclear energy. The first is the potential hazard to the local community and choosing appropriate geological locations to construct the power plants. Another is a strong regulatory infrastructure to promote harmonized safety standard. To increase the safety for not only those who work on the site but also live nearby a power plant must be responsible for the disposal of their nuclear waste – either to be buried in deep saline formations or be recycled back into the reactor as currently done by France and Japan

 

Resources:

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

http://fukushimaontheglobe.com/the-earthquake-and-the-nuclear-accident/whats-happened

http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/chernobyl-bg.html

 

 

Geothermal Energy: Going Green

Due to the island’s unique location and nature of formation, Iceland is the perfect country to lead the world in widespread geothermal energy use. The island is situated perfectly between the North American and Eurasian plates at a crack in the earth’s crust, and contains the two most important aspects of geothermal energy: enormous and continually renewed underground reservoirs, and shallow plumes of magma that heat the deepest sections of these reservoirs to upwards of 750 degrees Fahrenheit. On top of it all, the spreading of the seafloor below has become visible on land making Iceland one of the most geologically active countries on the planet.

Historically, Iceland has tapped into this geothermal energy as early as 1930 by straight piping hot water from the nearby springs into schools for heat. However, it wasn’t until the first oil shock of the 1970’s that truly made the country set out to make better use of this renewable and abundant energy source. By financing thermal and electric power plants throughout the country, as well as the infrastructure required to deliver hot water to homes, the Icelandic government not only eliminated the country’s dependence on fossil fuels for heating and electricity, but also jump-started an entire industry.

Geothermal energy works by tapping into water stored deep in the earth and using the steam generated from the heat of the earth’s core to power a steam turbine/generator which in turn generates electricity. The water is then pumped back down into the earth and reheated then reused.

Today, 99 percent of Iceland’s electricity is produced from renewable sources, 30 percent of which is geothermal (the rest is from hydroelectric), according to Iceland’s National Energy Authority. When transportation, heating and production of electricity are considered as a whole, geothermal provides half of all the primary energy used in Iceland. The capital, Reykjavik is home to the largest district heating system in the world, and it has been estimated that were Icelanders still dependent on oil, their heating costs would be five times as high. Across all of Iceland, 90 percent of households are connected to a district heating system, with just a few remote households getting their heat from fossil fuels such as propane.

 

Iceland is now the leading exporter of geothermal expertise to the rest of the world. Iceland’s third-largest bank, Glitnir, helped finance the world’s biggest geothermal district heating project in the city of Xianyang, China, and currently retains a staff of geologists to evaluate the potential of early stage drilling projects.

 

 

References:

http://iceland-times.com/section.php?id=167&id_art=184v

http://www.scientificamerican.com/article/iceland-geothermal-power/

http://www.nea.is/geothermal/

 

Thermoelectric Devices

Thermoelectric devices are in our everyday lives although many of us are not aware of their existence or how they actually function. All thermoelectric devices are powered through what is known as the thermoelectric effect.

This refers to the reaction caused when a difference in temperature creates an electric potential or vice versa. This specifically may be known as the Seebeck effect, the Peltier effect, or the Thomson effect, although each three laws have different specifics. For many materials, this effect is not productive or useful, but in certain materials that have a strong thermoelectric effect they can be used for things such as power generation and refrigeration.

Thermoelectrics generate the electricity from the movement of electrons within a metal.  Metals are good conductors because electrons can move freely within them, similar to a fluid in a pipe. Heating one end of a thermoelectric material causes the electrons to move away from the hot end toward the cold end.  When the electrons shift from one end to the other they cause an electrical current.

Below shows one generator prototype that uses thermoelectric energy

 

Although when many people think of thermoelectric devices the word heat comes to mind, thermoelectrics are also key in refrigeration and cooling devices. The Peltier effect was named after the man who discovered that when the electrons of a material are flowing from end to end, heat is absorbed at one end of the junction and released at the other.  This process forms the basis for thermoelectric cooling and temperature control, these are currently the widest applications of thermoelectric devices.  The device has two sides, and when DC electricity flows through the device, it brings heat from one side to the other, so that one side gets cooler while the other gets hotter. The “hot” side is attached to a heat sink so that it remains at ambient temperature, while the cool side goes below room temperature. In some applications, multiple coolers can be cascaded together for lower temperature.

 

 

 

Resources:

http://2.bp.blogspot.com/-oPUED7WQQao/UCaQ7BzkFlI/AAAAAAAAEF8/zL2YYsmYxkA/s1600/scheme_about_technology1b.jpg

https://powerpractical.com/pages/how-do-thermoelectrics-work

 

http://thermoelectrics.matsci.northwestern.edu/thermoelectrics/index.html