Improving building energy efficiency and daylight performance through the use of adaptive shading and the reflector light shelf (SRL)‎

Abstract EN

Highly glazed building facades have been increasingly built for aesthetics, daylight, and attempt to achieve green building ratings such as LEED.

Typically, as window areas increase, building energy consumption rises because of the excessive heat transfer through fenestration areas.

Fixed shading devices can effectively control solar heat gain; however, they considerably reduce daylight in the space.

This research provides a method to increase window areas to improve daylight performance without compromising building enCTgy efficiency.

The adaptive overhangs/fins are external automated shading devices that refract or extend according to the monthly profile angle of the sun in order to provide the minimum depth required to shade window areas.

The Selective Reflector Light shelf (SRL) was developed by the author in order to increase daylight performance while preventing the consequent rise of cooling loads in hot arid regions.

According to simulation results, the adaptive overhangs/fins system yielded in 24.8% savings in annual energy consumption.

At the same time, this system improved daylight admission during summer time.

When the SRL is incorporated, cooling loads were reduced by 7%, compared to a conventional light shelf.

Utilizing adaptive overhangs/fins and the SRL, window areas were enlarged from 30% to 50% of the wall area with only a o.lkbtu/ft2 annual increase and with significant improvements in illuminance levels.