IT’S TIME TO PUT YOUR ROOF WORK
Once the insulation and air-tightness of a house has been increased to a practical limit, it’s time to consider the use of renewable energy technologies to further reduce energy consumption and carbon emissions.
Solar energy is a popular choice of renewable energy for housing because it is discreet, requires no change in lifestyle by the occupier, and avoids locking the resident in to immature fuel supply chains. Houses are rarely inappropriate for solar energy – so long as the location is not shaded by other buildings or trees
If you have ever gotten in a warm car on a sunny winter day, you have experienced the thermal energy of the sun. The sun’s rays move through the glass of the car and warm the interior, although it may be quite chilly outside. Likewise, some people have actually baked cookies on the dashboard of their car on hot summer days. Again, thermal energy is being used.
In order to harness the energy from the sun and turn it into electricity, it is necessary to have solar cells to collect and transform solar energy into usable electricity. These cells are typically in the form of panels that face the direction of the sun to capture the most rays possible.
HOW A PV (photovoltaic) CELL MAKES ELECTRICITY
Under the sun, a photovoltaic cell acts as a photosensitive diode that instantaneously converts light – but not heat – into electricity.
A top, phosphorus-diffused silicon layer carries free electrons – un-anchored particles with negative charges. A thicker, boron doped bottom layer contains holes, or absences of electrons, that also can move freely. In effect, precise manufacturing has instilled an electronic imbalance between the two layers.
1. Photons bombard and penetrate the cell.
2. They activate electrons, knocking them loose in both silicon layers.
3. Some electrons in the bottom layer sling-shot to the top of the cell.
4. These electrons flow into metal contacts as electricity, moving into a circuit throughout a 60-cell module.
5. Electrons flow back into the cell via a solid contact layer at the bottom, creating a closed loop or circuit
POWERING HOMES & BUSINESSES WITH SOLAR
Current leaving a module, or array of modules, passes through a wire conduit leading to an inverter. This device, about the shape of a waffle iron, inverts direct current, which flows with a fixed current and voltage, into alternating current, which flows with oscillating current and voltage. Appliances worldwide operate on AC. From the inverter the solar-generated power feeds into circuitry of a household, business or power plant and onto the region’s electrical grid. A remote, or independent, power system also can form a self-contained circuit without connecting to the grid. The off-grid system, however, requires batteries to store power for times, such as night, when modules do not capture enough light energy from the sun.
THE UNITED SOLAR, INC.