Components of residential solar Electric system
A PV system components include PV modules (groups of PV cells), which are commonly called PV panels; one or more batteries; a charge regulator or controller for a stand-alone system; an inverter to covert solar power from direct current (DC) to the alternating current (AC) of the utility grid-connected system; wiring; and mounting hardware or a framework. A PV module arranges individual PV cells, and the modules are grouped together in an array. Some of the arrays are set on special tracking devices to follow sunlight all day long and improve system efficiency.
Solar panels are the most noticeable component of a residential solar electric system. Solar cells are small, square-shaped panel semiconductors made from silicon and other conductive materials, manufactured in thin film layers. When sunlight strikes a solar cell, chemical reactions release electrons, generating electric current. Solar cells are also called photovoltaic cells or “PV cells” and can be found on many small appliances such as calculators.
Solar Array Mounting Racks
Solar panels are joined into arrays and commonly mounted in one of three ways: on roofs; on poles in free standing arrays; or directly on the ground.
Roof mounted systems are the most common and may be required by zoning ordinances. This approach is aesthetic and efficient. The main drawback of roof mounting is maintenance. For high roofs, clearing snow or repairing the systems can be an issue. Panels do not usually require much maintenance, however.
Free standing, pole mounted arrays can be set at height that makes maintenance easy. The advantage of easy maintenance must be weighed against the additional space required for the arrays.
Ground systems are low and simple, but cannot be used in areas with regular accumulations of snow. Space is also a consideration with these array mounts.
Regardless of where you mount the arrays, mounts are either fixed or tracking. Fixed mounts are preset for height and angle and do not move. Since the angle of the sun changes throughout the year, the height and angle of fixed mount arrays are a compromise that trades optimum angle for a less expensive, less complex installation.
Tracking arrays move with the sun. Tracking array move east to west with the sun and adjust their angle to maintain the optimum as the sun moves.
Array DC Disconnect
The Array DC disconnect is used to disconnect the solar arrays from the home for maintenance. It is called a DC disconnect because the solar arrays produce DC (direct current) power.
Solar panels and batteries produce DC (direct current) power. Standard home appliances use AC (alternating current). An inverter converts the DC power produced by the solar panels and batteries to the AC power required by appliances.
Solar power systems produce electricity during the daytime, when the sun is shining. Your home demands electricity at night and on cloudy days – when the sun isn’t shining. To offset this mismatch, batteries can be added to the system.
Power Meter, Utility Meter, Kilowatt Meter
For systems that maintain a tie to the utility grid, the power meter measures the amount of power used from the grid. In systems designed to sell power the utility, the power meter also measures the amount of power the solar system sends to the grid.
For systems that are not tied to the utility grid, a backup generator is used to provide power during periods of low system output due to poor weather or high household demand. Homeowners concerned with the environmental impact of generators can install a generator that runs on alternative fuel such as biodiesel, rather than gasoline.
Breaker Panel, AC Panel, Circuit Breaker Panel
The breaker panel is where the power source is joined to the electrical circuits in your home. A circuit is a continuous route of connected wire that joins together outlets and lights in the electric system.
For each circuit there is a circuit breaker. Circuit breakers prevent the appliances on a circuit from drawing too much electricity and causing a fire hazard. When the appliances on a circuit demand too much electricity, the circuit breaker will switch off or trip, interrupting the flow of electricity.
The charge controller – also known as charge regulator – maintains the proper charging voltage for system batteries.
Batteries can be overcharged, if fed continuous voltage. The charge controller regulates the voltage, preventing overcharging and allowing charging when required. Not all systems have batteries: for more on the types of systems. (Cleanenergyauthority)
PV System Installation, Maintenance, and Longevity
You could install a photovoltaic (PV) or solar electric system yourself. But to avoid complications or injury, you will probably want to hire a reputable professional contractor @ www.vanpeux.com with experience installing solar systems. While they are sophisticated electric systems, PV systems have few moving parts, so they require little maintenance. The basic PV module (an interconnected, enclosed panel of PV cells) has no moving parts and can last more than 30 years while requiring little maintenance. The components are designed to meet strict dependability and durability to withstand the elements. The best way to ensure and extend the life and effectiveness of your PV system is by having it installed and maintained properly. Most PV system problems occur because of poor or sloppy system installation