Glossary

Active Solar - Capturing the naturally occurring energy from the sun and using it to provide energy thermal or electrical energy to the house. Active systems consume some amount of energy from another source to make the machinery run. Typically, active solar systems have very low losses when the sun isn’t shining.

Hydronic Solar Collector – A solar collector that heats water. Water flowing through the collector is heated. The energy gathered depends on the insolation and collector type. The two main types of hydronic collectors are evacuated tube and flat plate.

• Evacuated Tube – A metal tube with a working fluid inside is suspended in a large test tube shaped glass container. The metal tube has some sort of fin or collector plate attached to maximize the amount of area used to gather solar energy. It is contained within the glass test tube because the glass test tube has a vacuum inside, aka has been evacuated of gas. This keeps the energy that strikes the collector plate and metal tube from being re-released into the air. Evacuated tube type collectors collect less heat than flat plate types per area and per purchase dollar in moderate outdoor air temperatures. However, at low outdoor temperatures, evacuated tube collectors output more heat.

• Flat Plate – A heat absorbing sheet of metal with fluid channels inside collects solar energy and heats the fluid. The absorber sheet is contained within an insulated box, the 4 sides and back are insulated, and the front is insulating glass that is designed to allow as much solar energy in as possible. In moderate outdoor temperatures, flat plate collectors gather the most energy per area and per purchase dollar, however, at low outdoor temperatures, the heat loss though the insulated box becomes large enough that the evacuated tube collectors have the higher output.

Passive Solar – Capturing the naturally occurring energy from the sun and using it directly to heat the house without using any other energy to make the system operate. Typically, active solar systems have high energy losses when the sun isn’t shining.

Solar, Active - see Active Solar

Solar, Passive – see Passive Solar

Solar Panel – See Solar Collector

Solar Collector – A device that converts the solar radiation that it is exposed to into some form of usable energy. There are 2 primary types:

• Hydronic – A solar collector that heats water. See Hydronic Solar Collector
• Photovoltaic – aka PV – A solar collector that produces DC electricity. See Photovoltaic Solar Collector