EGEE 102
Energy Conservation and Environmental Protection

Active Solar Heating Systems


Solar heating systems are classified as “active” or “passive” solar heating systems, or a combination of both. We will first look at active systems.

Active solar heating systems are comprised of collectors, a distribution system, and a storage device.

Instructions: Click on the hot spots in the image below to find out more about the main components of an active solar heating system.

Active solar heating systems operate as follows:

  • Flat plate collectors are usually placed on the roof or ground in the sunlight. The top or sunny side has a glass or plastic cover to let the solar energy in. The inside space is a black (absorbing) material to maximize the absorption of the solar energy.
  • Cold water is drawn from the storage tank by pump #1 and is pumped through the flat plate collector mounted on the roof of the house.
  • The water absorbs the solar energy and is returned back to the tank.
  • Warm water from the tank is pumped by pump #2 though the heating coil.
  • The fan blows air (from the room) over the heated coil, and the heated air then passes into the room and heats the room.
  • Cold air sinks to the bottom and is recirculated over the heating coil.

Note: The standby electric coil is automatically turned on and provides the heat when the water temperature to the heating coil drops because of consecutive cloudy days.

Instruction : Click the “play” button to observe the operation of an Active Solar Heating System:

Operation of an Active Solar Heating System

Click here to open a text description of the operation of an active solar heating system.

Operation of an Active Solar Heating System

Water from the storage tank is pumped up to the roof-mounted solar panels. The sun heats the water as it travels back to the water tank. The warm water from the tank is moved by a separate pump through a series of coils inside an air furnace. The furnace moves cool air past the coils to be heated and then distributed throughout the building.

Collector’s Efficiency is the ratio of solar radiation that is captured and transferred to the collector or heat transfer fluid.

The efficiency of a collector can be expressed as:

Collector's Efficiency=( Useful energy delivered Isolation on collector ) × 100%

Typical collector efficiencies range from 50–70 percent.

Diagram of the inside of a solar plate collector, showing the glazing, tubes, absorber plate, and insulation.
Solar Plate Collector