With advancements in solar power, (which was the focus of the October Tech Talk), come the newer and better sun powered alternative energy called Photovoltaic. The old style solar panels or polycrystalline silicone cell, are the standard panels today taking the largest market share. However, they are only rated at 13% to 15% efficiency. The new monocrystalline silicone (photovoltaic) cell has a higher efficiency rating of 14-17%. Both are widely distributed and have a 25 year warranty. These panels are built to take a direct hit from a golf ball and can support a 180lb. man walking on its flat surface.
The newer Photovoltaic system requires a highly qualified person to design, as there are so many factors that must be incorporated into the system in order to achieve a successful outcome. Most residential PV systems are somewhere between one to four kilowatts (1,000w to 4,000w). This will require at least 100 to 400 square feet of roof space. Briefly, this system will take up a considerable amount of roof or ground space, and will require cooperation between a photovoltaic designer, your electrician, and your utility company. Keep in mind that your system only generates power when the sun is out, and usually is designed to supplement your normal incoming power. If you have a very low personal load, the electric power created can go back to the utility company for credit, which is the ideal situation. To save or store this electricity, a large, well ventilated room must be used to hold the deep cell batteries. Very expensive, and normally not used, the batteries have a short shelf life, and require a very large room to accommodate them.
For commercial application, the photovoltaic system works best, since the normally flat roof used with commercial construction can accommodate the needed number of panels required to be effective in reducing energy use.
Next time, Tech Talk will tackle Geo Thermal systems.
Steve Martin is the President of Steve Martin Ent. Inc., and specializes in the design and installation of alternative energy HVAC systems in Pawling, New York.
