What is solar radiation?
Solar radiation is a short-wave, extremely energy-rich radiation consisting of:
Name |
Approx. distribution |
UV-light |
5% |
Visible light |
53% |
IR |
42% |
Table: showing the wavelength distribution of sunlight - 320nm-2500nm
Graph of the light intensity for the different wavelengths of sunlight
The importance of daylight
We often want to have as much daylight as possible in a room as it has positive effects on the wellbeing of humans. In the illustration above, daylight is the same as visible light. Effective solar protection glass removes more or less all UV and IR, but a major disadvantage is that much of that longed-for daylight also disappears. As a window is a fixed installation, you cannot control the amount of light in the room.
Solar variations over the year
The height of the sun changes throughout the year, which means that different demands are made on the same sun blinds in summer and winter.
Summertime
In summer, excess temperature due to solar radiation streaming in is the biggest problem. As the sun is high in the sky, the problem of glare is not an issue. Instead, the function of the sunblind is to prevent the rays of the sun from being turned into heat in the room.
Wintertime
In winter, allowing the sun to stream in is instead an advantage as it heats the room, but the working environment can be impaired by this.
As the sun is low in the sky during the winter, it shines straight in through the window and causes problems with glare. As our solar control collection is a flexible solution, you can alter your sunblind depending on what you need on any particular day. A number of newly built houses have what is known as roof projections which project out a short way above the window and thereby shade the window from the rays of the sun. This system works well in summer, but it can be problematic in winter as the sun is so low in the sky that the projection does not help, which causes major problems with glare.