So you’ve decided it’s time to learn more about using the sun’s energy to power your home, but where do you start? How about figuring out the differences between the 4 most popular solar technologies?
Solar photo voltaic systems are the most common type of solar technology in use today. Photo voltaic cells are made of semi-conducting materials which take photons from the sun’s light and convert them into electricity. Unlike other renewable technologies, Solar PV systems have no moving parts, and last for about three decades, or longer, depending on the solar panels that are used, and the quality of the installation. The beauty of Solar PV is that the electricity it generates can be used for any of your electronics, and isn’t just restricted to heating your home (like transpired solar collectors), or heating your water (like solar water heaters).
Concentrated Solar Power
Concentrated Solar Power (CSP) systems, also known as solar thermal systems, use mirrors or other reflective surfaces to create heat in a concentrated spot. This concentrated heat is used to superheat water to create steam, and, ultimately, turn a turbine. CSP systems are usually only viable in large, commercial applications.
There are relatively new technologies which allow electricity from CSP systems to be generated 24 hours a day, because these systems use massive heat storage containers. Here’s how they work: Sunlight is reflected from each heliostat (which track the sun) onto a central receiver at the top of the tower. Sodium and Potassium Nitrate Salts are pumped from the “cold salts tank” up to the receiver where they absorb the concentrated solar thermal energy, reaching temperatures of up to 565 degrees Celsius (1049 F). The heated salts are then pumped to the “hot salts tank” where they can be stored in their molten state or be used to generate electricity using the heat engine. The molten salts can be used to generate electricity for 15 hours. It’s, fundamentally, still just a steam driven power plant. The southwest U.S. has many Concentrated Solar Power plants.
Solar Water Heating
Solar Water Heating Systems contain a solar collector that heats water for your home or your pool. There are both active and passive solar water heaters. Active water heaters have circulating pumps and controls whereas passive systems do not. In climates that are not prone to freezing, a direct active circulation system is your best choice, in which the water is heated directly. In climates that are prone to freezing, an anti-freeze type fluid is used along with a heat exchanger to transfer heat to the water. Solar water heating is often an attractive option just because the typical American Household spends $400-$600 on water heating per year. In fact, water heating accounts for 14% to 18% of your utility bills.
Transpired Solar Collectors
Transpired solar collectors use heat from the sun to preheat air that is then ventilated through the house. Here’s a quick explanation of how they work: Collector panels are installed several inches from a south facing wall. The sun heats the collector panels, and ventilation fans draw the heated air through the panel perforations. Heated outside air is distributed through the existing air distribution system. The air may be preheated an extra 30 to 70 degrees Fahrenheit in the winter. In the summer the hot air is vented away from the wall behind the collector panels, cooling the building.Transpired solar collectors may reduce heating costs by $3-10 per square foot of collector, yearly.
What’s right for your home?
While there are multiple solar technologies available, it’s important to assess your specific needs when choosing a renewable energy source. If you think Solar PV may be the right option for your home, learn more from the blog posts below: