Courtesy of SolarRoofs.com
Solar Water Heaters have always been the first step when "going solar" due to low cost and high power density. The weight of conventional collectors made the installation very difficult and expensive until the advent of SolarRoofs.com's patented and proprietary series of light weight, affordable Skyline® collectors. Our efficiently designed solar thermal systems will save you money on energy no matter what energy source (gas, electricity, propane, oil, etc.) you currently use to heat your water.
Understanding the difference between solar thermal energy and solar electric energy is very important. Solar Electric is more commonly referred to as Photovoltaic (PV), in which energy from the sun is converted to electric power. Solar Thermal energy, however, simply uses energy from the sun to heat water. Both PV and Solar Thermal technologies can be used together or separately. While PV is used to power the electric needs of an entire home or building, Solar Thermal is an excellent choice for solar water heating.
The revolutionary light weight, attractive design of the Skyline® Solar Water Heater makes solar water heating truly practical for everyone. The 30% Federal Tax Credit and fast rising fuel costs make now the time to install a solar water heating system! Domestic solar water heaters are a cost effective way to generate hot water for your home. Appropriate in any climate, the fuel these systems use is FREE from the sun!
On average, water heaters use as much energy as a medium-sized car uses in a year. Each installed solar water heater is comparable to increasing the fuel mileage on the family car by over 60%. Supplementing millions of existing water heaters with SolarRoofs.com’s advanced solar thermal water heaters frees up huge amounts of limited energy resources that can then be used to produce electricity.
How Does a Solar Water Heater Work?
Solar water heaters do three basic operations before the hot water comes out of your faucet:
1. Energy Collection: Sunlight, short wave energy, is collected and converted to heat which is long wave energy. The solar collector is mounted on or near your home facing south. As the sunlight passes through the collector’s plastic or glass "glazing," it strikes a metal or rubber absorbing material. This material converts the sunlight into long wave heat, and the glazing prevents the heat from escaping much like a greenhouse. It is like leaving a car parked in the sun with its windows rolled up. The temperature inside a glazed solar collector on your roof can easily reach 300°F when there is no heat transfer fluid flowing through it.
The most common types of solar collectors used in solar water heaters are glazed flat plate collectors. A glazed flat plate collector consists of a shallow rectangular box with a transparent plastic or glass “window” covering a flat black plate or selective "Chrome" coating. The black plate is attached to a series of parallel tubes or one serpentine tube through which water, or other heat transfer fluids pass.
2. Energy Transfer: Circulating fluids like water in an "Open Loop" or Propylene Glycol in a "Closed Loop" transfer the collected energy in the form of heat to a storage tank. Heat energy is transferred from the collector to the water storage tank. In some water heaters, hot fluid is pumped from the collector to the storage tank. The pump is powered by electricity that either comes from an electrical wall outlet or a small photovoltaic module located near the collector.
3. Energy Storage: Solar-heated water is stored in an insulated tank until you need it. Hot water is drawn off the tank when tap water is used, and cold make-up water enters at the bottom of the tank. If additional heat is needed, it is provided by electricity or fossil fuel energy by the conventional “backup” water-heating system.
Solar water heaters tend to have larger hot water storage capacity than conventional water heaters. This is because solar heat is available only during the day and sufficient hot water must be collected to meet evening and morning requirements.
How well an active solar energy system performs depends on effective siting, system design, location, and installation. Solar thermal water heating systems, which use the sun's energy rather than electricity or gas to heat water, can efficiently provide 50 to 90% of your hot water needs—without fuel cost or pollution and with minimal operation and maintenance expense.
Courtesy of http://www.solarroofs.com