Basic Electricity, Solar Orientation and Load Analysis
How To Design With Solar Panels Designing with solar panels starts with determining the size of the system based on how much sunlight you will receive and how much energy you plan to use. .
Solar Radiance To determine the size of the system, you will measure the daily electrical usage you need and divide it by your solar radiance. Solar Radiance is the amount of sunlight that hits a surface, which changes depending on the time of the year.Image credit: g2solarsolutions.com
July PV Solar Radiation Map(Flat Plate, Facing South, Latitude Tilt) Image: “Photovoltaic Systems” by James P. Dunlop
January PV Solar Radiation Map(Flat Plate, Facing South, Latitude Tilt)Image: “Photovoltaic Systems” by James P. Dunlop
South Facing Solar Array A South facing solar array is the best position to absorb the most sunlight for the northern hemisphere. The suns angle changes +15° in the summer and -15° in the winter.
Latitude and AngleImage: “Photovoltaic Systems” by James P. Dunlop The angle at which a solar array is set to face the southern sun varies based on your latitude. In the winter the angle should be 15° more and in summer 15° less or fixed at the location’s latitude. Austin’s latitude is 30° so the best winter angle is 45° and Summer angle is 15°.
Shade Obstacles Solar panels should be free of shade from trees, objects and buildings from 9am-3pm or their performance will be reduced significantly. Image: “Photovoltaic Systems” by James P. Dunlop
Solar Pathfinder A Solar Pathfinder device is used to analyze exactly where the shadows will be at different times of the day or year so that the solar array is placed inImage: livingindryden.org the best spot.
Radiant Energy Radiant Energy is electromagnetic energy that travels in waves, including visible light, radio waves, x-rays and gamma rays. Example: Sunshine is radiant energy, provides warmth and fuel that makes life on earth possible.
What is the solar radiance for Austin?• http://solarelectricityha • Which angle has the ndbook.com/solar- nest solar radiance for irradiance.html Austin?
Electrical EnergyElectrical Energy is thepresence and flow of anelectrical charge, often storedin a battery and usuallydelivered through a wire in theform of electrons.Example: Electrical energy isstored in a cell phone and in a Solar Power Mobile Phone Chargercar battery. It also travelsthough power lines and intoyour home.
Basic ElectricityElectricity has its own set of units. The three most basic inelectrical systems are Voltage, Amperage and Wattage.Voltage is the measure of the "push" of electric current. The higher thevoltage, the more force there is to push the currentthrough the wire.Amperage is a measure of the amount ofelectric charge passing a point per unit time.Wattage gives the rate at which work isdone or energy is used.Volts x Amps = Watts
Water Pipe Analogy Think of electricity like plumbing.The voltage is the waterpressure.The amperage is the ratethe water flows.The wattage is the sizeof the pipe.
CircuitsImage: “Photovoltaic Systems” by James P. DunlopElectricity travels in closed loops, or circuits. It must have acomplete path before the electrons can move. If a circuit isopen, the electrons cannot flow. When we flip on a lightswitch, we close a circuit. The electricity flows from an electricwire, through the light bulb, and back out another wire.
What is the difference betweenAC and DC electricity? Image: www.solarguys.com.au
Direct Current (DC) Thomas Edison discovered Direct Current (DC) where the flow of electricity is in one direction only and substantially constant in value. Direct current runs though battery powered devices, solar cells, and LED lights. Photo credit: good.is
Alternating Current (AC) Nikola Tesla discovered Alternating Current (AC) where the electric charge periodically reverses direction at regularly recurring intervals and is transmitted to customers by a transformer. Alternating current runs though car motors, radio signals and appliances.Photo credit: good.is
Electric Meter The electric meter measures the amount of energy consumed by a building. The watt is a unit of power The kilowatt (kW) = 1000 watts The kilowatt hour (kWh) is most commonly used in electric bills by the utility company
Load Analysis The first step in designing a solar array system for a building is to do a load analysis to find out how much energy your system will need to produce. The load is the amount of energy an electrical appliance consumes when operating and is usually written (in watts) on the back label. It is very import to use energy efficient appliances when sizing a building for solar energy to minimize the energy need and cost of the system.