REVIEW OF BUILT ENVIRONMENT IMPACTS: DAY LIGHTING

DAY LIGHTING

The day lighting design is not just how to provide enough daylight to an occupied space, but how to do so without any undesirable side effects. Beyond adding windows or skylights to a space, it involves carefully balancing heat gain and loss, glare control, and variations in daylight availability. A building should orient to south-north for maximum day lighting. Deviation from due south should not exceed 15° in either direction for best solar access and ease of control.

A successful day lighting design shall make use of the exterior shading and control devices. In hot climates, Exterior shading devices often work well to reduce head gain and diffuse natural light before entering the building. Examples of such devices include light shelves, overhangs, horizontal louvers, vertical louvers, and dynamic tracking of reflecting systems.

EMBODIED ENERGY THROUGH BUILDING MATERIALS

In building design processes, specifying materials of construction is one of the vital parameter. Large amounts of energy is spent on the manufacturing of the materials and for their transport. Conservation of energy through building materials is very important in limiting GHG emissions. Researches show that less energy intensive building materials like for various building components are as follows:
1. Roofing-Filler Slabs
2. Terracing-Mud Phuska
3. Super structure-Ashlar Masonry with cement mortar
4. Foundation-Fly ash bricks

Not only these but there are vernacular materials available locally which can prove not only cost effective but also less energy intensive.

ENERGY EFFICIENT LIGHTING

Electric lighting is a major energy consumer. Using less electric lighting reduces heat gain thus saving air conditioning loads and improving thermal comfort. By installing new lighting technologies, buildings can reduce the electricity consumed. The following are few examples of energy saving opportunities with efficient lighting.

1. Installation of CFL,s in place of Incandescent lamps
2. Use of energy efficient Fluorescent lamps in place of conventional CFL,s
3. Installation of LED,s in place of CFL,s in offices/show rooms
4. Installation of sensors
5. Adding lighting controls and photo sensors

In addition to daylight controls, other electric lighting control strategies should be incorporated where they are cost effective, including the use of:
Occupancy controls: Using infrared, ultrasonic, or micro-wave technology, occupancy sensors respond to movement or object surface temperature and automatically turn off or dim down luminaries when rooms are left unoccupied. Typical savings have been reported to be in the 10% to 50% range depending on the application.
Timers: These devices are simply time clocks that are scheduled to turn lamps or lighting off on a set schedule. If spaces are known to be unoccupied during certain periods of time, timers are extremely cost-effective devices

It is proven by Siemens that every building on an average has the potential to improve the energy efficiency by 25-30%(www.simmons.com). This can be achieved by optimizing the Building management systems, lighting, heating , cooling systems and water and energy distribution system(Griggs,2009)