Solar power homes. Do they fill the need for free, clean, renewable, and eco- friendly energy?

They cannot fill the need for FREE energy, despite statements to that effect. Initial costs of solar power homes are too steep for the bank accounts of many. Once the photovoltaic (PV) panels and other elements of a solar home are installed, of course, the sunlight itself is free. But how many years will it take to recoup that initial investment? Will solar homes someday be within the scope of reality for everyone?

Solar Power Homes’ Initial Cost

The initial cost of solar power homes depends on a number of factors. How large is the solar home? Is the solar home being purpose built to that end, or is it being converted to a solar home? Is the landscaping oriented to solar power? Is the solar home to be in a good “solar” climate?

A house that is purpose built to be a solar home will initially cost a little more than a conventionally built house. The cost will be affected by your decision to have the solar home tied to the grid or off the grid. The list below is not all-inclusive, but gives an idea of items needed.

* Photovoltaic (PV) Panel System: Size of the system depends on your usage. An average, 3,000 watt grid-tie system we priced cost about $20,000 for everything - before installation. A 1080 watt off grid system for an average solar home was offered at $10,000 complete, before installation.

* Solar Water Heater System: A system to preheat water going into a standard water heater will cost about $3000 for the same solar home.

* Trombe Wall: Composed of masonry, this solar home wall is covered on the outside with glazing. Sunlight passes through the glazing, generating heat. The heat is conducted through the wall into the solar home for heating, out of the solar home for cooling. Costs will depend on size of wall, masonry, glazing, and labor.

* Solar Sun Room: This large room on the south-facing (in the northern hemisphere) side of the solar home has large expanses of un-shaded vertical glass to collect solar energy. The collected heat is stored or passed into the remainder of the house for winter heating. This means your solar home must have a large “extra” room that a conventional house would not have.

* Fluorescent Light: A solar home will not use conventional incandescent light bulbs. More costly compact fluorescent light bulbs will reduce the amount of solar energy needed.

* Appliances/Electronics: When selecting appliances and electronics for the solar home, you select energy-efficient over those that offer more “bells and whistles”. You select propane or natural gas appliances over electric.

A good place to begin if you are having a solar power home built ground up on your site is to choose a builder who is committed to building 100% ENERGY STAR qualified homes. Such homes are energy-efficient inside and out. The initial investment will be more than a conventional home, as already noted. The on-going savings, however, can be passed down to future generations.

This article is for those between ages 10 and 110. Children are discovering new information every day. Senior citizens are, too, and many do not understand solar panels. They have not had an opportunity to study the technology and learn how solar panels work. So this article is basic. It is simple. It is for all those, of any age, who are beginning to learn how solar panels work.

Solar Panel Defined

Solar panels are photovoltaic (PV) cells mounted in a frame. Solar cells are modular. Things that are modular have units that can be “plugged in” to increase the size. You can plug in more PV cells to increase the size of a solar panel.

The “photo” part of the word “photovoltaic” refers to light and the “voltaic” part refers to electricity. Solar panels collect sunlight and change it into electricity. Of course, this does not mean that sunlight can electrocute you as lightning might. Something must happen to it inside the solar panel.

So How Do Solar Panels Work?

A solar panel is a large, flat box filled with small cells, or compartments. Read the points below to see how solar panels work.

* Silicon: The cells of solar panels are made of very thin slices of silicon. Silicon is the same substance you find in sand. If you walk on a beach, you are walking on mostly silicon. There is more silicon on Earth than almost any other element.

* Cooking Silicon: To make the thin slices for solar panels, manufacturers must “cook” silicon at extremely high temperatures.

* Adding Chemicals: Chemicals are added to the silicon. Boron and phosphorous are the most common. Adding these chemicals makes the silicon “come apart” more easily. We say that it becomes unstable. It doesn’t hold its electrons as tightly after these chemicals have been added.

* Electrons: The electrons of silicon are very small particles - too small to be seen under a microscope. Electrons move around within the chemically changed silicon of a solar panel.

* Contacts and Wires: Metal contacts are placed on the tops and bottoms of the silicon cells. Electric fields are set up by the contacts. Wires are inserted to carry the electric produced.

* Photons: Sunlight that hits a solar panel contains “photons” - small bundles of electrical energy. When photons hit the silicon of a solar panel, the solar cells swallow some of them. We say the photons are absorbed. The energy of the absorbed photons knocks loose some of the silicon’s electrons.

* Electricity Produced: The loosened silicon electrons flow through the wires of the solar panel. Electric fields force them to flow in one direction. This flow of electrons is electricity.

Using the Electricity

Once your solar panels change the sunlight’s energy into electricity, you can use it just as you would use electricity from the power company. You can send the power to light bulbs, a television set, a computer, or even a satellite.

If you need more power, you connect more solar panels to your first solar panel. This is called a solar system or solar array. The more solar panels you add, the more electricity you can produce.

Summary

How do solar panels work? Almost like magic. Once you install a solar panel, there is very little you have to do. The silicon cells collect sunlight; photons in the sunlight knock loose silicon electrons; electrons flow through wire; and you get electricity.

Teachers need to educate rising generations in the nature and use of solar panels. Children reaching secondary levels should already have a basic understanding of both passive and active solar power. They should have read about solar panels, and they should have hands-on understanding as well. How can we accomplish that?

An experiment with solar panels and clouds will go far toward helping youngsters grasp necessary concepts. This experiment takes little in the way of materials or preparation. You will need a solar building kit, available from Scientifics Online and other science educational suppliers.

Before doing an experiment with solar panels and clouds in class, teachers themselves should work through the entire experiment so they will be able to direct it skillfully.

Experiment with Solar Panels and Clouds

To experiment with solar panels and clouds, you need the following supplies. Groups can share.

* The solar panel and motor from a solar building kit
* 2 pieces of clear plastic, each piece large enough to cover the solar panel
* 1 piece of colored plastic large enough to cover the solar panel
* 1 length of wax paper sufficient to cover the solar panel
* netting material, such as a cargo net, to cover the solar panel
* lightweight “see-through” cloth to cover the solar panel
* 1 light source, preferably sunlight

An experiment with solar panels and clouds should be preceded with a brief discussion of what might be expected to result. Students have a basic understanding of how solar panels can harness and convert the sun’s power. What happens, however, when clouds come between the sunlight and the solar panel? Will that reduce the amount of energy produced? By how much?

After discussion, divide your students into small groups. If you have enough solar building kits, divide into groups of 3 to 5 students.

Begin the experiment with solar panels and clouds by giving each group the following instructions:

1. Connect your solar panel to the motor.

2. Turn the solar panel so it faces the light source as directly as possible.

3. By listening to the motor, you can judge how rapidly energy is being produced. Make a note of how fast it sounds to you.

4. Create a “wispy cloud” by holding one piece of clear plastic between the solar panel and the light source. Listen to the motor again. Note any difference in how fast it is running. Would this amount of cloud cover be likely to affect the efficiency of solar panels?

5. Continue your experiment with solar panels and clouds, changing your “cloud” by placing both pieces of clear plastic together and holding them between the solar panel and light. Note any change in the speed of your motor. Would this type of cloud affect solar panels?

6. Change the “clouds” again by using the colored plastic, then each of the remaining materials in turn. Record carefully every change in the motor’s sound and speed.

When every group has completed the experiment with solar panels and clouds, compare notes. Discuss which materials let more solar power reach the solar panel, and which reduced the amount of solar power.

Have students write their conclusions.