Passive use of solar energy
Passive solar energy use describes the use of thermal radiation for the temperature control of a building without any additional aids than the building envelope itself. The greenhouse effect is used for this. Within the German Energy Saving Ordinance , the effect is z. B. by offsetting solar heat gains to reduce the heating energy requirement .
functionality
Sun rays hit the interior through the windows of a building and heat the components, which store the heat and release it again with a time delay. The air heated in the room by solar radiation can also lead the heat to components that are not directly illuminated and heat them up. The following have an optimizing effect on the passive use of solar energy for buildings: Long hours of sunshine during the heating season, south-facing glazing, size of glazing, light transmission capacity of glazing (g-value), freedom from shading of glazing, storage capacity of internal and directly irradiated components, absorption capacity ( black surface) of the irradiated components.
Structural requirements
A building envelope that is as well insulated as possible, including a passive house , in order not to lose the recovered energy again immediately, and a movable or rigid shade option to prevent the inside of the building from overheating in the event of strong and persistent solar radiation. Direct sunlight is effective; But diffuse light radiation ( global radiation ) is also effective and can also reach windows on the side facing away from the sun and lead to energy input. In principle, transparent components other than windows also let light into the interior. The transparent thermal insulation should be mentioned here, but not further explained.
The contradiction in the requirement for the glazing itself must be taken into account. On the one hand, a high degree of energy transmission (g value) of the pane is required, which, however, is accompanied by a high heat transfer coefficient (U value) of the pane. The glasses with high thermal insulation properties let in little solar radiation. A glass with a medium U-value, medium g-value and additional temporary thermal insulation, such as B. a thermally insulated sliding or folding shutter for the night.
literature
- Martin Kaltschmitt , Wolfgang Streicher, Andreas Wiese (eds.): Renewable energies. System technology, economy, environmental aspects . Springer Vieweg, Berlin / Heidelberg 2013, ISBN 978-3-642-03248-6 .
Individual evidence
- ↑ Solar heat gains Qs . In: enev-weka.de .