<p>Solar (rev9sed (2013)</p><p>Photo voltaic, solar water heating, passive solar</p><p>Solar..."never play more than a supporting role in the alternative energy scenery" Other "experts claim the opposite. I think future energy generation will require multiple sources coupled with energy efficiency and sustainability practices. DG solar water heaters convert more of the spectrum into heat than PV into electricity solar strength varies, clouds, sun angle with peak sun usually at mid day the orbit and tilt of the sun influences solar strength sun's energy 35% reflected away from earth 43% absorbed as heat by atmosphere and surface 22% evaporates water 0.2% creates wind 0.02 used by plans</p><p>PV materials must be a uniform crystalline structure monocrystaline silicon best and most $ Poly crystalline lower efficiency but cheaper</p><p>About 16% efficient in converting solar to elect 30-40% is probably the top efficiency due to technical limitations with materials and limited spectrum conversion energy payback on embedded energy of production is about 3 years.</p><p>Pros & Cons Weather, hours of sun, pollution, dust solar currently generates 30 watts per square meter – New York uses 55 watts per meter, so the area needed to power New York is nearly twice the size of New York - pave Florida DG</p><p>1 Solar energy is expensive compared to current fossil, but less so if costs of pollution are considered, carbon tax. Again cheap natural gas is an issue here</p><p>Solar panels are visible green “Look at me. I’m green even when I fly off to a distant vacation!” Boy am I cynical. (DG) net metering = when you don't need electricity it goes back onto the grid, but at wholesale or retail costs? Time of use charges noon-6 can make solar more economical</p><p>Solar good for peak use times </p><p>Passive Solar building orientation (south) window placement, awnings, skylights, trees insulation and ventilation can save 70% of bills by incorporating solar features.</p><p>PV Solar Great uses run remote ag pumps road way signs roadside call boxes, buoys, electric fences power DC motors remote cabins</p><p>Using the power where it is generated saves money and energy losses resulting from the grid and costs associated with running wires to these remote locations.</p><p>Solar hot water black barrel sealed tubing systems little external power needed</p><p>Solar water purification to power evaporation of polluted water</p><p>2 Utility-grade power plants = big PV "farms" in the desert</p><p>Solar condenser power generators focused sun heats water for steam turbine operation costly, maintenance</p><p>Home solar</p><p>FIRST MAKE THE BUILDING OR PROCESS EFFICIENT BUILDING MODIFICATION, ENERGY MANGEMENT, BEHAVIOUR CHANGE</p><p>Richard Perez, founder of Home Power magazine, asserts that every dollar invested in energy efficiency saves $3 to $5 in the cost of a solar system." p 56</p><p>Start with an audit. And you know how to do an audit, right????? Reduce electrical use</p><p>Solar Process</p><p>Site Survey geographical, local conditions and global position shading building roof suitability or available land accessibility of the array for installation and maintenance proper mounting and angle of PV modules</p><p>ASSESSMENT OF ELECTRICAL USE AFTER EFFICIENCY MEASURES to determine the size of array needed</p><p>Types of systems Grid connected Grid tied the solar supplements traditional electrical delivery – excess generation goes into the grid MOST POPULAR</p><p>Grid connected Grid tied the solar supplements traditional electrical delivery – excess generation goes into batteries</p><p>3 Off Grid PV and other sources provides all electrical (often hybrid systems</p><p>Components</p><p>Array type of array – panels, shingles, films ???? efficiency vs costs roof mounted, part of the building (awnings) mounted away from building, solar car park angle of array, fixed, variable, or tracking thermal load on the roof – keeping the modules cool since efficiency goes down as the modules heat up wind loads and snow loads structural integrity of roof or building components grounding lighting protection permitting and inspection requirements</p><p>Batteries use deep cycle lead acid batteries need to be recharged promptly after deep discharging, do not leave at low charge for a long time need maintenance, keep warm 75 -80 perform more poorly when cold 50 -80° range if too cold loose efficiency, too hot makes hydrogen gas (boom) ensure ventilation (prevent boom) safety using tools (spark = boom, electrocution) keep batteries as fully charged as possible manage electrical use based on state of charge (off grid) check water level – use distilled water check electrolyte monthly keep batteries clean clean terminals</p><p>4 equalize = controlled overcharge to drive lead sulfite crystals off the plates so they won't flake off, stirs the electrolyte, brings all battery cells to the same voltage since a weak cell reduces overall voltage determine the frequency of equalizing by testing voltage to detect if a battery is at low voltage, or test electrolyte specific gravity, if large differences then equalize sealed batteries do not equalize or loose water (?) special caps to reduce moisture loss and capture hydrogen and oxygen</p><p>Charge controller prevents overcharging, diverts power to a reserve load like a heat strip to prevent overcharging Over discharge protection, disconnects loads if charge gets too low</p><p>Off grid needs wind and/or generator which requires maintenance</p><p>Inverters convert DC from modules to AC for use stand alone, off grid – will contain battery charger and controls plus and controls for operating the generator set high and low voltage controls interactive inverter when grid-tied since PV voltage must match grid voltage and frequency will disconnect when the grid goes down. multifunction inverter are grid tied with battery charging</p><p>Critical specifications input and out put voltage modified square wave (less efficient for loads and can damage loads like electronics) vs sine wave (grid tied) Surge capacity efficiency </p><p>Buy the best unit you can afford</p><p>5 Commissioning = starting and operating a system for the first time. transfer from contractor to owner, warranties start at that point installation conforms to system design documents conductors are correct type and size wring is correct, protected and secure connections are tight and identified equipment is securely mounted array mounting is secure roof/building penetrations are properly sealed safety features and operations and controls are functioning labels and warnings attached documentation complete initial startup- follow procedures in equipment manuals – usually start from the array all technical specifications must be correct learn maintenance and operating procedures</p><p>Maintenance</p><p>Modules inspect modules for damage or breakage, bent frames delaminating shade control – trees grow up soiling = accumulation of dust and dirt, birds, smoke, dust, moss clean carefully electrical shock remove debris like leaves inspect mounts for corrosion, attachments, sealing of penetrations inspect roof from below if possible tilt adjustment</p><p>Battery Maintenance requires most maintenance in system</p><p>6 open vent vs sealed batteries for maintenance battery mounts ventilation safety when using tools terminal inspection and cleaning, loose connections</p><p>Specific gravity looking for equal readings between cells, state of charge float type hygrometer refractive index hydrometer load testing to see if batteries will maintain voltage under load capacity testing a load test for a set period of time.</p><p>Resources</p><p>Photovoltaic Systems, Dunlop, J. P., American Technical Publishers</p><p>Very detailed for installation technician</p><p>Solar Electricity Basics, Dan Chiras, New Society Publishers</p><p>Excellent introduction especially for individual installations</p><p>Local Wind and Solar resources http://www.otherpower.com/otherpower_wind.shtml</p><p>Excellent, off the grid, alt energy folks. Seem really experienced and informed.</p><p>7</p>