Glossary
1. Active system
Solar heating system requiring external mechanical power to move the collected heat.
2. Antireflection Coating
A thin coating of a material applied to a solar cell surface that reduces the light reflection and increases light transmission.
3. Array
A set of photovoltaic panels connected together designed to produce a significant amount of electricity. A home solar electric system might include several arrays on different parts of the roof.
4. Azimuth
The direction a solar electric system faces (e.g. north, south, east, west).
5. Balance of system
All the parts of a solar electric system excluding the solar panels and the inverter. Balance of system usually includes items like racking, wires, conduit, and safety shut-offs.
6. Base load
The average amount of electric power that a utility must supply to meet the energy demand.
7. BTU
British Thermal Unit(s). A measure of energy output defined as the amount of heat needed to raise one pound of water 1°F from a starting point of 39.2°F. Common unit in measuring solar hot water performance and sizing gas-fired water heaters.
8. Building permit
Authorization from the local building inspection agency to construct or modify a building from an approved set of plans, usually required for solar energy installations.
9. Carbon dioxide (CO2)
The colorless and odorless gas, is a natural air component. It is, however, also created in huge quantities by the burning of fossil energy sources. Due to its excessive accumulation in the atmosphere, it has a greenhouse effect on the atmosphere and it is responsible in part for global warming.
10. Cell
The smallest part of a solar panel that converts light into solar electricity.
11. Closed loop system
Solar hot water system in which the fluid circulated throughout the solar thermal collectors is separate from the potable water. In a closed loop solar system, the solar heat is transferred to the potable water by way of a heat exchanger.
12. Closed-loop system
Solar hot water system in which the fluid circulated throughout the solar thermal collectors is separate from the potable water. In a closed loop solar system, the solar heat is transferred to the potable water by way of a heat exchanger.
13. Conductivity
A measure of the ability of a material to permit conduction of heat flow through it.
14. Conductor
A material that conducts or allows the flow of heat, electricity, or other forms of energy.
15. Conduit
A piping system that protects and routes electrical wiring.
16. Conversion efficiency
The percentage of the sunlight incident on a solar panel that is successfully passed to the system as current.
17. Data monitoring
These systems are installed after the solar electricity system and record the amount of electricity generated, thus providing information about the current operation of the installation. Today, monitoring is possible via Internet, cell phone or large-format displays.
18. Degradation
(1) The disintegration or deterioration of the parts or materials beyond a repairable condition, thus requiring replacement. (2) The loss of efficiency of solar cells over a long period of time.
19. Direct Current (DC)
A type of low voltage electrical current. DC electricity is produced by solar cells and must be converted, by the inverter, into AC before it's usable in a house.
20. Drainback system
A closed-loop solar hot water system that uses an atmospheric pressure drainback tank. In order to avoid freezing or overheating the water flowing through the collectors drains back into a storage tank when not being pumped. A coil-type heat exchanger in the tank then transfers the solar heat to the targeted fluid.
21. Electric current
A flow of electrons; electricity, amps.
22. Energy Audit
A survey that shows how much energy used in a home, which helps find ways to use less energy.
23. Expansion tank
A tank used in a hot water system or radiant heating system that provides space for the expansion of the heat transfer fluid.
24. Fixed tilt array
A photovoltaic array set in at a fixed angle with respect to horizontal.
25. Flat plate collector
A solar energy collection device in which sunlight is converted into heat using a metal plate, typically copper, over which the water flows. It typically consists of a metal frame, glazing (protective sheet of glass or plastic), energy absorbers (usually metal), and insulation and uses a pumped liquid as the heat-transfer medium.