A Very Abbreviated Glossary of Solar Terminology

• passive solar: A system that harvests the sun’s energy “passively”, without the use of other sources of power (such as electricity) or energy-consuming moving components. Typically, heat-absorbing systems which trap and/or hold the heat energy of sunlight.
• active solar: A system that harvests the sun’s energy using “active” moving or electrical components to capture energy from the sun - often pumps, fans or photovoltaic panels.
• photovoltaic (PV),
  also, solar electric system: A system that generates electricity from the sun’s electricity by direct conversion of light energy into electrical energy, by the use of a semiconductor device.
• battery-based
  or battery-less: Battery-based solar electric systems use a storage battery to store or ballast electricity until it is needed. Battery-less solar electric systems can only provide electricity during hours of sunlight, but can be much more efficient & require less maintenance than battery-based ones.
• grid-tied,
  grid-intertied,
  or standalone: A solar electric system may be standalone, having no connection to the utility grid (though it may still power isolated house circuits). Or it may be connected to the utility grid in some manner, being able to complement power supplied by the utility company: A grid-tied system has no batteries and is “tied to” - completely dependent on - the presence of the grid to generate and supply power, whereas a grid-intertied system can also supply power to buidling circuits from batteries.
• inverter: An electronic device which converts DC electricity, often from batteries or solar panels, into AC electricity, often for the purposes of powering standard household appliances, or feeding power back into the utility grid.
• roof mount,
  ground mount,
  or building-integrated: Descriptors indicating where/how a solar panel is mounted: on a building roof, on a rack mounted on the ground, or physically integrated into a roof or wall of a building. A “tracker” mount, often atop a pole, “tracks” the sun, moving the solar panels to follow the sun’s movement throughout the day.
• hot-water solar system: A solar system that utilizes the sun’s energy to heat water, usually to help meet domestic hot water (dhw) needs, though, in some cases, the water is also used for space heating (paticularly in conjunction with a “radiant-floor” heating system..
• hot-air solar system: A solar system that utilizes the sun’s energy to heat air, for direct circulation in a building, or to transfer the heat to another medium.
• heat recovery systems: Systems that “recover” heat that otherwise would be wasted for use in a building. An example is a drain pipe mechanism that is able to transfer some of the heat in warm water that is flushed down the drain to colder water that is coming into the building, warming the incoming water and reducing the amount of energy needed to heat it.
• crystalline
  or amorphous: Two common forms of photovoltaic material, each with its own characteristics of efficiency, fragility, heat sensitivity, costs of production, degradation, etc.