Passive+Solar+Power

=It's Getting Hot in Here: Passive Solar Power =  Brian P. Fehlau Passive solar power is the capture of the sun's light and heat rays with the purpose of heating objects directly - like a lizard sunning itself on a rock! Passive solar power is generally considered when constructing the windows, walls, and roofs of buildings [1].

This picture illustrates a house design that would take advantage of passive solar power. The roof has a long overhang that will block out the sun's rays during the summer months (when heat is not needed and the sun is directly overhead) but allow the sun's rays to enter the many windows during the winter (when the sun is at a lower angle) [2]. This picture illustrates a trombe wall. This type of wall is specially designed to absorb solar energy (only during the winter months) and to transfer this energy efficiently into the home [3].

media type="youtube" key="lzGaLw__kdk" height="385" width="480" This video, although looking a bit dated (and cheesy?), does a very good job describing how a solarium with a wall of south-facing glass can help to heat a home without the need for fossil fuels. It explains buildings that are considered to have "Zero Energy" design [4].

**Recent News Article: ** [|"Green Homes Face a Red Light"] This article explains that, while green technologies used in homes are energy-efficient, these technologies don't add much to the value of the homes. This makes it difficult for home-owners and/or builders to obtain the funds they need to make their homes more energy-efficient. **Advantages: **
 * This type of energy production takes advantage of the sun - a RENEWABLE and FREE resource! (Although, it does take money to build structures that take advantage of passive solar power).
 * Passive solar power is generally used to replace fossil fuel power, and passive solar power does not release any of the emissions that fossil fuel power releases.

**<span style="font-family: Georgia,serif; font-size: 17px;">Disadvantages: **
 * <span style="font-family: Georgia,serif;">This type of energy production relies on the sun shining without cloud cover. Regions that receive high level of precipitation may not take best advantage of passive solar power.
 * <span style="font-family: Georgia,serif;">Often, passive solar power takes advantage of changing sun angles throughout the year, so it is used most effectively at middle latitudes.

<span style="font-family: Georgia,serif;">**<span style="font-family: Georgia,serif; font-size: 17px;">Steps of Energy Production: ** <span style="font-family: Georgia,serif;"> <span style="font-family: Georgia,serif;">
 * 1) <span style="font-family: Georgia,serif;"><span style="font-family: Georgia,serif;">The sun is essentially a nuclear fusion reactor. During the nuclear fusion reactions, photons of light waves and heat waves are released [5]. These photons travel to the Earth.
 * 2) <span style="font-family: Georgia,serif;">When the photons hit objects on the Earth, they are either absorbed or reflected by the objects. In order for passive solar power to be harnessed, the objects involved must easily absorb the photons.
 * 3) <span style="font-family: Georgia,serif;">The objects that absorb the sun's photons increase in temperature, and heat conduction can be used to heat other objects using this increased temperature. This heat conduction is the goal of passive solar power.
 * 4) <span style="font-family: Georgia,serif;">Unlike other types of energy production, passive solar power does not result in the production of electricity.
 * <span style="font-family: Georgia,serif; font-size: 17px;">Conservation of Energy: **
 * 1) <span style="font-family: Georgia,serif;">The chemical potential energy in the atoms of the sun are transformed into the light energy and heat energy of the photons. These photons travel with kinetic energy to the Earth.
 * 2) <span style="font-family: Georgia,serif;">The light energy and heat energy of the photons are transformed into the heat energy of the objects that absorb the photons.
 * 3) <span style="font-family: Georgia,serif;">The heat energy of these objects is transferred to other objects.
 * 4) <span style="font-family: Georgia,serif;">No electrical energy is produced in this process.
 * <span style="font-family: Georgia,serif; font-size: 17px;">Relevant Vocabulary: **
 * <span style="font-family: Georgia,serif;">Chemical Reaction - the fusion reaction in the sun is an example of a chemical reaction
 * <span style="font-family: Georgia,serif;">Electromagnetic Spectrum - the spectrum include light waves and heat waves, two types of waves that are useful in passive solar power
 * <span style="font-family: Georgia,serif;">Heat Energy - this can be absorbed by objects on the Earth's surface, and this energy is easily transferred to other objects
 * <span style="font-family: Georgia,serif;"><span style="font-family: Georgia,serif;">Light Energy - visible light can be asborbed by objects on the Earth's surface
 * <span style="font-family: Georgia,serif;">Photon - the photons from the sun are absorbed during passive solar power generation
 * <span style="font-family: Georgia,serif;"><span style="font-family: Georgia,serif;">Trombe Wall - a type of wa ll that efficiently absorbs the sun rays and transfer heat energy into a home or building

<span style="font-family: Georgia,serif; font-size: 17px;">**Footnotes:**
 * 1) <span style="font-family: Georgia,serif;">__Passive Solar Energy__. 20 September 2008. AEoogle. 31 March 2010. <[]>.
 * 2) <span style="font-family: Georgia,serif;">Picture citation: http://farm3.static.flickr.com/2351/2077815149_707f43950f.jpg.
 * 3) <span style="font-family: Georgia,serif;">__Residential Buildings: Walls__. 5 June 2009. U.S. Department of Energy. 31 March 2010. <[]>. Picture citation: http://upload.wikimedia.org/wikipedia/commons/3/3d/Illust_passive_solar_d2_319pxW.gif.
 * 4) <span style="font-family: Georgia,serif;">__Passive Solar Energy - Glass is All You Need__. 8 March 2008. Zero Energy Design. 2 April 2010. <[]>.
 * 5) <span style="font-family: Georgia,serif;"><span style="font-family: Georgia,serif;">Layton, Julia and Freudenrich, Craig. How the Sun Works. 2010. HowStuffWorks, Inc. 1 April 2010. <[] >.