Photovoltaic and Thermal Solar Renewable Energy Sources

Solar energy is the heat and light radiated from the Sun that powers Earth's climate and supports life. Solar technologies allow controlled use of this energy resource. Solar power is a synonym of solar energy or refers specifically to the conversion of sunlight into electricity by photovoltaics or conversion in to thermal energy. EnergyXchange uses solar energy for both electricity and thermal heat.

Currently the EnergyXchange campus has an eight panel photovoltaic array with a tracking device that allows the array to move with the movement of the sun.  The array is producing electricity for our visitor center.  The arrangement EnergyXchange has with the power company is called ‘net metering’.  With net metering, the electricity being produced is used directly by the facility. EnergyXchange only draws electricity from the grid when more is needed then is being produced.  Another possible option between array owners and the power company is called “sell all.” For particular information on these agreements contact your local power company and visit www.ncgreenpower.org for information regarding tax credits.

In addition, EnergyXchange has ten thermal panels that provide heat for the aquaponics fish tanks.  Heated water and glycol are circulated from the thermal panels through coils in the fish tanks and back to the thermal panels. In this manner the water in the fish tanks is maintained above 60 degrees even in the Winter.

Photovoltaic (PV) Systems

Photovoltaic systems convert sunlight directly into electricity. Commonly known as "solar cells," these systems already power more than 1 billion handheld calculators, as well as millions of watches, portable lights and battery chargers. Larger, more complex systems provide electricity to pump water, power communications equipment, light homes and operate appliances.

The heart of a PV system is a solid-state cell made of semiconductor material like that used in microelectronics. It's usually silicon, the basic ingredient in common beach sand.  The cell's semiconductor "wafer" is specially treated to form a positive electric field on one side and a negative field on the other, and electrical conductors are attached to both sides.  When sunlight strikes the cell, it knocks loose electrons, which are captured in the form of electric current.

Thermal Systems

Thermal systems convert sunlight into thermal energy, most often providing heated water.  The overall process involves the use of solar collectors filled with water, or some other fluid, being place in a location with good access to direct sunlight.  The heated water is then piped to a location where the captured heat can be used to provide hot water for personal use or comfort heat.

For more information on solar energy, check out these links:
www.gosolarnc.org
http://www.ncsc.ncsu.edu/
http://www.ases.org/