Facade Engineering

Solar gain when the air is the warmest in summer increases energy consumption and has a great influence on the indoor environment. Methods to decrease the effect of direct solar radiation are to slope the exterior south-facing wall and to set solar shading on the wall etc. Therefore we recommend a method for designing the facade with consideration for reducing annual energy consumption. We introduce 16 cases of system simulation where the angle of the sun from vertical is from 0 to 30 degrees, and solar shading length (L) is from 0 to 1.5 meters. They are as follows:

  

This is the relationship between solar altitude angle and primary energy consumed where L=0 to 1.5m. Primary energy consumption can be reduced as much by solar shading as by designing the external wall at an angle from the vertical.

 

This is the relationship between the angle of the sun from vertical (θ) and annual energy cost where L=1.5m. angle of the sun from vertical of 0 to 30 degrees can reduce annual running costs by 3 to 7%.

  

Cooling or Heating

This is the relationship between the angle of the sun from vertical (θ) and energy for cooling or heating where L=1.5m. Increasing the angle of the sun from vertical (θ) decreases the energy required for cooling and increases the energy for heating. Solar radiation has a heating effect on the indoor environment in summer and winter. In other words, blocking solar radiation reduces heat gain in summer but increases energy requirements for heating in winter. In Japan energy consumption is reduced by employing this method, since cooling loads in general are considerably greater than heating loads.
It is obviously important when designing a facade to consider both architectural design (e.g. site planning etc.) and annual energy consumption.