Solar gain is the increase in temperature of a space, object or structure as a result of solar radiation.
The amount of solar gain increases with the strength of the sun, but can be reduced by intervening materials with the ability resist the radiation. Objects struck by sunlight absorb the short-wave radiation from the light and re-radiate the heat at longer infrared wavelengths.
Where there is a material or substance between the sun and the objects struck that is more transparent to the shorter wavelengths than the longer, then when the sun is shining the net result is an increase in temperature – solar gain.
Solar Radiation is radiant energy emitted by the sun from a nuclear fusion reaction that creates electromagnetic energy.
Whilst the term radiation conjures up negative thoughts, and prolonged human long exposure to UV radiation can be harmful, solar energy as a whole provides essential daylight and warmth that should be embraced and harnessed by any intelligent building design.
Insolation is the measurement of solar radiation on a surface. It is the amount of solar energy received over a given area in a given time. It is commonly expressed as watts per square meter (W/m2).
Solar Load is the amount of radiation passing through a vision area relative top the floor area of the space. The Solar Load is used to show the comfort level for the building occupant.
Horizontal Projecting Shading is where there are a series of blades projecting directly out from the façade. This configuration works best on South, South-East or South-West facing elevations, although there can be some benefit on other orientations, dependant on the projection.
Generally a greater projection blocks more radiation, although for a South facing elevation, there is very little additional benefit by increasing the projection more than 0.8 times the window height.
For windows that are tall and narrow, increasing the width of the shading beyond the jambs of the window is more effective than increasing the projection of the shading.
For other elevations they are less effective unless a large projection is used.
Horizontal Parallel Shading is where a series of horizontal blades are mounted above one another and connect directly to vertical façade.
This configuration is the most effective at blocking radiation, although the amount of transmittance will depend on the angle and the set-out of the blades, as well as the amount of reflectance afforded by the colour. It can also block out a lot of day light too.
For South West and South East elevations, a blade angle of 0° will block out most of the incoming solar gain, whilst allowing for some view out too. On other elevations the blades will require a greater degree of tilt in order to block out solar gains.
Vertical Parallel Shading is where vertical blades project out either side of a window, or connected directly to the transoms on a vertical façade. For window applications, the blades should extend well beyond the top of the frame for the best results.
This configuration is most effective on the North elevation where the blades can block out most of the sunlight, but it also makes a useful contribution on the North-East and North-West.
Horizontal Projecting Shading
Horizontal Parallel Shading
Vertical Parallel Shading