Solar photovoltaic (PV) cells are semiconductor devices that create DC electricity from the sun. Because an individual cell produces very little current (about 0.5VDC) they are typically assembled into modules, which normally produce from 5 to 200W of DC electricity. These modules are configured into arrays, and with the appropriate conversion equipment can be used to power a wide range of electrical devices.
Common applications of PV power include residential, commercial, and remote industrial. Residential and commercial systems incorporate a grid-tied PV inverter that converts DC to AC electricity. When the home or business is using less electricity than the PV system is generating, the excess is sold into the electric grid, resulting in direct energy cost savings to the owner. If the utility grid fails, the PV inverter shuts down instantly, thus posing no safety hazard for grid-tied utility repair crews. Even homes with PV systems will be left in the dark during a power outage.
To keep the lights on, Alpha manufactures the Solaris 3500XP, the only product currently on the market that combines critical UPS functionality with the capability of selling solar-generated electricity back to the utility. Availability of PV generated power allows extended critical load runtime for long outages by recharging the batteries when the sun is shining.
For remote applications, solar power is often less expensive than extending utility lines for a grid connection. Alpha's fully integrated Solar Power Systems (SPS) incorporates PV modules, a battery charge controller, batteries, necessary fusing and surge protection, and any required electricity conversion equipment. The SPS is a freestanding power system that derives 100% of its energy from the sun, so every effort should be made to reduce the load's power draw and energy usage. Because the SPS is a DC system, it is preferred to eliminate unnecessary DC/AC conversions and provide DC directly to the load. Because the solar resource varies by geographic location, Alpha specifies the daily energy output of each SPS by region according to estimated solar radiation maps.
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