Solar thermal energy can be used for different building applications: direct or indirect space heating and domestic hot water production (DHW).The heart  of a solar thermal system is a “Collector”.The solar collectors absorb energy and transport it directly to the desired place or to the storage.Generally in active solar thermal systems, , two media are used to transport the heat: Liquid and air.

 ♦ Air Collector Solar Systems

The air collector solar systems use solar energy to preheat the outdoor fresh air for building ventilation and space heating. This is a low cost technology with low CO₂ emission while improving the air quality. It is most suitable technology for large applications like commercial and industrial buildings, where large amount of energy is needed for space heating and industrial process heating.Solar air collectors can be usually divided into two categories:

  • Glazed air solar collectors
  • Unglazed transpired air solar collectors

Glazed air Solar Collector

Unglazed Transpired air Solar Collector




♦ Hydraulic Systems

Hydraulic systems ,unlike air systems, can easily store the solar gain and are used suitably for producing domestic hot water (DHW) as well as for space heating. The medium of these systems is mainly water-charged with glycole in variable % ages,  according to the climate,in order to avoid freezing.Different solar thermal systems are avaiable and can be classified according to their technologies:

  1. Evacuated tube collectors >>>
  2. Glazed flat plate collectors >>>
  3. Unglazed flat plate collectors >>>



Several major factors must be considered when choosing, sizing and positioning a solar thermal system: ∙ Area availability on the different envelope parts ∙ Seasonal solar radiation on these surfaces ∙ Desired solar fraction (i.e. the portion of the building’s energy covered by the solar system), and available storage possibilities


See Also:

• Envelope Integration Possibilities »»

• Storage»»