A Guide to Solar Light, Heat, and Energyby: David Miller
When the sun is shining, it emits light and heat. This light and heat is a form of energy that is called solar energy. When it reaches the Earth, it can be used to create electricity. Because it comes from the sun, which is a constant, it is known as a renewable power source and can be used in the same ways as the energy created by using fossil fuels. The history of utilizing the sun dates back to Egyptians who created homes and other buildings that would retain the heat from the sun to keep people warm at night. In Rome, bath houses were known to have south-facing windows to help keep them heated. In the late 1800s it was discovered that sunlight could be used as a power source. Specifically, electricity could be produced by exposing a material called selenium to light. In modern times, the first silicon solar cell was discovered in the early 1950s. Unlike the solar cells of today, they were only able to power small devices. By the 1960s, solar cells were used to provide power to both United States and Soviet Union satellites. From the 1970s forward, the use of solar cells and panels has become increasingly more common both commercially and privately, although the cost for adding solar paneling to homes remains high. Today, greater numbers of people are looking to solar panels as a way to become energy independent and to help save the environment.
Harnessing Solar Energy
Solar energy has many uses and can be a renewable, alternative source for electrical lighting, heating, cooling, and other electrical needs. To use solar energy, it must first be harnessed. The methods to do this are classified as either active or passive. The use of photovoltaic cells is a common example of an active method. The sun may also be harnessed in a passive way. This is a method that people have both intentionally and unintentionally accomplished for centuries. How a home or building is designed, the materials that are used and even certain colors are classified as passive ways to harness solar energy. For example, the placement of a window or even a sky light can passively harness the heat of the sun to warm a room or a building. Passive solar energy is limited, however, in the amount of heating or cooling that is accomplished. Both methods have advantages and disadvantages. The most obvious advantage of harnessing solar energy is that it does not create greenhouse gases, which are harmful in terms of personal and environmental health. Another benefit is that it is renewable energy and won't use up natural resources. Unfortunately, the need for energy is constant, day and night, rain or shine. This is a problem when it comes to solar energy as the sun does not shine at night and during heavily clouded days. Storing electricity created from solar energy has not been perfected and continues to be problematic.
- Energy Information: Five Solar Energy Facts
- Washington State University - Solar PDF
- Energy Kids: Solar Basics
- Passive Solar Design: Heating and Cooling Using Natural Sunlight
- DTE Energy: Solar Power for Kids
- Tennessee Valley Authority: Solar Power
- Harness the Power of the Sun
- Northeastern University: An Introduction to Solar Energy
Photovoltaic cells, or solar cells, are made using an upper and lower layer of silicone or some other semi-conductive material. One of the layers is positive and the other is negative. Between the two layers, there is a space that separates them. When sunlight strikes the uppermost side, its energy is absorbed by the silicone, which knocks electrons loose so that they are free-flowing. The electrons are captured as an electric current by conductors that are attached to both the positive and negative layers. The electrical current is then used to power objects. Electricity can be created at higher voltages when individual cells are connected together in a frame to create a photovoltaic module. Wiring large numbers of modules together will create a photovoltaic array. The size of either the module or the array, and the amount of sun that comes into contact with them, will determine the amount of electricity that is created. Both create what is known as a direct current (DC) electricity.
Solar panels are another term for solar modules. These modules are typically made up of approximately 40 cells. When used to produce electricity, more than one panel is needed. For example, when mounting solar panels for a home, there may be up to 20 panels. They are generally placed on the roof where they have the most direct access to the sun; however, they may also be installed on the ground with panels directed towards the sun. Solar arrays are used when large amounts of electricity are needed. Depending on the need, hundreds of arrays may be connected to produce the maximum amount of electricity. Historically the popularity of solar panels has been hindered by cost. As panels and their installation become more affordable, solar panels become more popular. In addition to cost, more people turn to solar panels in efforts to have a renewable power source and to decrease their reliance on utility companies.
- Northwestern University: What Are Solar Panels?
- Energy Saving Trust - Solar Panels(PV)
- National Renewable Energy Laboratory: Solar Photovoltaic Technology Basics
- European Union - Energy Kids: Solar energy - Thermal and PV Installations
- Scientific American: How Does Solar Power Work?
- Miami University Ohio: What is Solar Power?
- Penn Electric Racing: How Solar Cells Work
- Colorado State University Extension: Harvesting Energy from the Sun: Solar Photovoltaic
- University of Central Florida: How PV Cells Work
- Government of Texas: Energy Home - Photovoltaic Cells
Solar Energy in the Home
A family can save money and energy by installing solar panels in their home. Panels can last for 30 years or longer, making them a good investment towards a goal of being more energy-efficient at home. When purchasing solar panels it is important that buyers check the efficiency of the panels before purchasing them. In addition, they should be installed properly, away from any shade and facing the correct direction, which is typically south. This will help ensure that a person is getting the best performance from his or her panels. In efforts to save money, a person can take additional steps, such as using solar water heaters. Solar water heaters are used to heat water for the home and even to cut the costs of heating a hot tub or swimming pool. Solar water heaters may be either active or passive in nature.
If solar panels are too expensive, passive methods may be used to become more energy-efficient and save money. When building or purchasing a home, attention to the placement of windows, the structure of the home and materials that are used to build it can save money in heating and cooling costs over time. Even with the assistance of solar energy in powering the home, there are steps that a person can take to become more energy-efficient. Caulking and otherwise sealing up areas that can cause a draft can assist in keeping excess cold or heat out of the home. The installation of insulation in one's home can also help it to be more efficient. Purchasing and using a renewable thermostat is also a way of improving one's energy efficiency. When buying appliances, check for the Energy Star label. Appliances with this label are designed to use less energy than products without the designation.
- Passive Solar Housing
- United States Environmental Protection Agency: Solar Energy At Home
- National Geographic: Pros and Cons of Solar-Powered Home Systems
- University of Florida: Solar Power System
- HGTV: Solar Power at Home
- University of Hartford: Investing in Photovoltaic Technology
- The History Channel: Solar-Energy System Installed At White House
- Save Money and More with Energy Star Qualified Solar Water Heaters
Solar Energy Fun
In many ways, educating children about solar energy is as important as educating adults. The earlier kids understand the need for renewable energy, the more comfortable they will be with using energy more wisely and with using alternative energy sources, such as solar energy. Teaching children about solar energy can be fun, and there are numerous resources available to help parents. In some cases, children may learn about energy efficiency and solar power while they are in school.
- Solar Town Kids: Activities, Games, and More!
- State of California - Energy Quest: Solar Energy Science Projects
- Hands on Books: Solar Energy with Kids
- Solar Is Future: Kids
- NASA: Play Power Up!
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