Types and Uses of Solar Energy

By: Stephanie Collinge, Joseph Trahan, and Wes Crochet

Advantages/Disadvantages

Advantages• Save money to operate• Reduce air pollution (99%

less)• Reduce dependence on

imported oil• Solar plants last as long as

nuclear or coal (30 to 40 years)

• New plants have low land use

• Backup and storage devices available

• Greatly reduce CO2 emissions.

Disadvantages• Making solar cells

produces toxic chemicals• Old solar cell plants take

up large land area• Can damage fragile desert

ecosystems• Need backup systems at

night and during cloudy/rainy days

• Solar plants costly to build

How does solar energy heat houses and water?

There are two main methods (passive and active). A passive solar heating system uses energy efficient windows, as well as green houses attached to the actual house, which face the sun to collect the heat and energy. The structure of the house must also be made of heat absorbing/retaining material (such as stone, brick, adobe, etc.) In an active solar heating system, a house or structure contains panels on the roof which acquire the heat. The heat energy is then transferred to the house and can be used immediately, or can be stored for later used.

How can we use solar heat for energy?

• Central receiver system – numerous mirrors surround a tower. The mirrors track the sun and reflect the energy onto the tower, which stores the energy.

• Distributed receiver system – many mirrors are spread out in rows in a field. The mirrors are all focused on oil filled pipes, which are heated and then used to power turbines and generate electricity.

• Nonimaging optical solar concentrator – a long tube traps solar energy, then intensifies it about 80,000 times.

• Solar cookers – on a smaller scale, these heat boxes acquire solar energy and heat food within the box.

How is electricity produced from solar energy?

Solar energy can either be stored as heat, or converted to electricity. In order to convert the energy to electricity, the energy must be converted to photovoltaic cells (commonly known as solar cells). Individually, the cells produce a tiny amount of energy. But when grouped together, the cells can produce electricity that can be stored in batteries, used to turn on and of lights, or complete other tasks that require conventional electricity.

Sun Facts • Currently, solar cells provide

less that 1% of the worlds commercial energy.

• According to Royal Dutch Shell International, renewable energy (including solar) could account for 50% of the worlds energy by 2050.

• In 2001, the European Union adopted a law requiring its countries to get 12% of their total energy and 22% of their electricity from renewable energy by 2010.

• With advances in technology, solar energy will continue to become cheaper and more common.

Solar Energy Model

Terms from Model• turbo-alternator -Device that uses steam to convert the mechanical force generated

by the rotation of the turbine into electricity. • electricity transmission network -Electricity is carried over vast distances by a

network of cables that extends from the power plant to consumers. • transformer -Device used to alter the electric voltage; the voltage is increased at the

plant outlet in order to carry the current over long distances. • condenser -Circuit that cools the steam from the turbine and condenses it into water,

which is reintroduced into the steam generator. • steam generator -Device that uses heat to convert water into steam to activate the

turbo-alternator. • cold coolant -After releasing its heat to the steam generator, the cold coolant returns

to the boiler. • hot coolant -The coolant extracts heat from the boiler and carries it to the steam

generator and turbine. • pump -Device that ensures that the cold coolant liquid flows to the boiler. • bank of heliostats -Heliostats: remote-controlled adjustable mirrors that follow the

Sun’s trajectory and concentrate solar radiation toward the boiler at the top of the tower.

Terms continued…• solar radiation -The Sun emits waves in the form of luminous radiation (41% visible

light, 52% infrared light and 7% ultraviolet light).

• solar ray reflected -Solar rays trapped by heliostats are sent to the boiler. •

coolant –Fluid (e.g., a mixture of melted salts) that traps the heat from concentrated solar radiation and carries it to the turbine.

• tower –Structure atop which the boiler sits and collects luminous energy; it can reach 325 ft in height.

• boiler -Enclosure in which the concentrated heat from the Sun’s rays raises the temperature of the coolant.

Test Questions

1. Why is Solar Energy not a more widely used form of energy?

2. What is Concentrating Solar Power?

3. The Sun emits waves in the form of______ radiation?

4. What is Solar Energy?

5. What is more environmentally friendly, Solar Energy, or fossil fuels?

Answers

1. Currently, it is very expensive to create new plants, and maintain plants. Also, the net energy and efficiency levers are too low for solar energy to be widely used.

2. This term refers to the method of solar energy production where mirrors are used to focus, or concentrate, the solar energy towards on large tower located in a central location, (known as a Solar Power Tower).

3. Shortwave radiation (UVA, UVB and Gamma)

4. The radiant energy emitted by the Sun, OR energy derived from the Sun's radiation.

5. SOLAR ENERGY!!!

Article Reviews• http://googleblog.blogspot.com/2006/10/corporate-solar-is-coming.html.

As solar energy becomes more advanced and more common, businesses and corporations are finding out that homes and power plants are not the only ones who can benefit and use solar energy. Leading the way, Google has now built solar panels on and near the headquarters in San Francisco, California in an attempt to become more energy efficient, as well as lead the way in switching over to renewable energy.

By Wes Crochet

• http://www.reuters.com/article/pressRelease/idUS179330+12-Jan-2009+BW20090112

On January 12, 2009, a leading nationwide commercial developer of distributed solar energy facilities (SEFs) announced that they had launched 19 new solar energy facilities. These facilities, located mainly in California, provide energy to several corporate clients, three universities, two healthcare facilities, a water district, a wastewater treatment facility, and a public school. The SEFs will produce enough clean renewable energy to offset 8,723 metric tons of carbon annually.

This is a big step for solar energy, and renewable energy use. Although acquiring solar energy is still high in price, this signifies the decline in price, and the raise in renewable energy awareness and use.

Article Reviews continued…http://topics.nytimes.com/top/news/business/energy-environment/solar-energy/index.html

  With the numerous harmful fuel sources used in the world today, solar power is an opportunity for a real environmentally friendly means of energy. While it only accounts for about one percent of energy in America, it is an increasingly popular source in European countries such as Spain and Germany, and we Americans need to follow in their footsteps. The most popular way to go about gathering solar power is called concentrating solar energy, which involves using mirrors to generate heat and turn the generators. The drawback to solar energy is that it is very expensive to produce and transfer.

By Joseph Trahan

http://www.sciencedaily.com/releases/2008/05/080508181259.htm

A group of students at Rowen University created a means of gathering solar power that is very cost efficient. Usually Solar panels consist of two dimensional panels of copper that gather and transfer the heat, but they have now created a three dimensional panel that they believe will be both more inexpensive and more efficient. It will cost between five and ten percent of what it costs now, and will be just as efficient.

By Joseph Trahan

 

Article Review continued…• Solar Energy

http://topics.nytimes.com/top/news/business/energy-environment/solar-energy/index.html

This article compares the U.S. use of solar energy to Europes. Only one percent of the U.S. uses solar energy, California using most of it, opposed to Europe where countries like Spain and Germany use it at a high price. The article also discusses different ways to convert the suns power to generate electricity, like concentrating solar power using mirrors which is shown in the picture above. Solar energy is also used to heat water and pools.

• Solar Power for Residential Homes

http://facts-about-solar-energy.com/solar-power-for-residential-homes.html

This article discusses the uses and costs of solar energy in your home. some houses have what are called solar photovoltaic panels. This type of solar panel is often used to heat pool water and provide some or all of the household's hot water needs. the most common household need is to heat water for the swimming pool. The solar power system required for this application is very simple and low cost. The basic idea of the article is you can get solar power for cheap if you install it yourself.

Some sunny jokes…

What do you call a silly old man? - A fossil fool!

What did the California wind farm say when it met Governor Arnold Schwarzenegger? - We're big fans of yours!