Glossary
Alternating current (AC) - The flow of electricity that constantly changes direction between positive and negative sides.
Ampere (Amp) - The unit of measure that indicates how much electricity flows through a conductor. For example, a 1,200-watt, 120-volt hair dryer pulls 10 amperes of electricity current. (amps = watts/volts)
Azimuth Horizontal angle measured clockwise from true north; 180° is true south. Photovoltaic systems are typically mounted at an angle that accommodates both the high summer sun and the low winter sun, maximizing its efficiency at all times of year. While a photovoltaic system can operate without directly facing the path of solar energy, the closer it comes to meeting this path, the more efficiently it works. However, this efficiency is often traded off with the additional cost of certain mounting structures.
Balance of System - These components provide the interconnections and standard safety features required for any electrical power system. These include array combiner box, properly sized cabling, fuses, switches, circuit breakers and meters.
Battery Bank - The battery bank contains one or more deep-cycle batteries, connected in series and/or parallel depending on the voltage and current capacity needed. The batteries store the power produced by the solar array and discharge it when required. (battery information)
Circuit - One or more conductors through which electricity flows.
Controller - Prevents the batteries from overcharging, over discharging or other control functions. The charge controller may also monitor system operational status.
Converter - An apparatus that changes the quantity or quality of electrical energy.
Direct current (DC) - The flow of electricity that flows continuously in one direction.
Grid or Electric Grid –The electricity transmission and distribution system that links power plants to customers through high-power transmission line service, this will generally be your local gas & electric company. Are you connected? Can you sell back unused power? What is the net metering agreement?
Inverter - Device used to change direct current electricity to alternating current electricity.
Kilowatt (kW)1000 watts - A unit of measure of the amount of electricity needed to operate given equipment. For example, one kW is enough power to illuminate 10 light bulbs at 100 watts each. (volts x amps = watts)
Kilowatt-hour (kWh) - The amount of kW produced over a period of time, or one kilowatt of electricity supplied for one hour. For example, a one kW system, if operating at full capacity for 5 hours will produce 5 kWh of electricity.
LEED - LEED is a third party certification program and the nationally accepted benchmark for the design, construction and operation of high performance green buildings.
Main Fuse Box - Main breaker-box that connects to the circuits in our house.
Megawatt - One thousand kilowatts or one million watts. One megawatt is enough to power 1,000 average California homes per day.
Meter - Surplus AC power is recorded by the meter as it goes to your energy provider's grid.
PV (Photovoltaic)/Solar Modular Terms:
Note: Below instances where PV and Solar are interchangeable are shown as PV/Solar. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight, while the term photovoltaic cell is used when the source is unspecified. (See our page on pv/solar components/modules.)
Photovoltaic (PV) energy – Direct conversion from sunlight to electricity. PV systems have no moving parts, totally non-pollutant, require virtually no maintenance, and have cells that last for decades.
--From CELLS to Panels to Arrays--
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PV/Solar Cells is a device that converts light energy into electrical energy by the photovoltaic effect.
- PV/Solar Module – Packaged interconnected assembly of photovoltaic/solar cells is comprised of several individual photovoltaic cells connected in series or parallel with a metallic material.
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PV/Solar Panel: a collection of modules that are mechanically fastened together, wired, usually with a glass covering and a frame and backing made of metal, plastic or fiberglass, are known as a photovoltaic panel or solar panel.
- Photovoltaic Array/Solar Array is a linked collection of photovoltaic modules made of multiple interconnected solar cells. The modules are connected in series and/or parallel to provide the voltage and current levels to meet your needs. The array is usually mounted on a metal structure and tilted to face the sun.
Power Conditioners (Inverters) - The electrical equipment used to convert power from a photovoltaic array into a form suitable for subsequent use. Loosely, a collective term for inverter, transformer, voltage regulator and other power controls.
Solar Thermal A form of power generation using concentrated sunlight to heat water or other fluid that may then used to drive a motor or turbine.
Tilt The angle of inclination of a solar collector measured from the horizontal.
Watt (W) - Electric measurement of power at one point in time, as capacity or demand. For example, light bulbs are classified by wattage. (1000 watts = 1 kilowatt)
