Ashutosh Jha, LEED Expert and Senior Architect at Mohamed Salahuddin Consulting Engineering Bureau in Bahrain, talks about the importance of integrating daylight into design.
There has been a lot of discussion regarding sustainable development and green building techniques, how to conceive and how to design. I strongly believe that green buildings are the only logical way forward for the architecture and design community. For the next 50 years the focus should be on sustainable design and energy conservation while optimisation for any building should be at the top of any designer’s agenda.
The Middle East has huge amounts of sunlight and it makes perfect sense to use this resource effectively by incorporating it early in the design process. It is very important to understand the concept of daylight and its effective use in interior space. It has potential to reduce the energy consumption of any building and it works with all projects such as offices, hotels, hospitals and residential communities.
I believe that the following design guidelines, if adopted early in the process, can give excellent results regarding energy conservation.
UNDERSTANDING DAYLIGHT – Daylighting is the practice of placing windows and reflective surfaces to control the admission of natural light in order to provide effective internal lighting during daylight hours in order to maximise visual comfort and reduce energy use.
SUN PATH, MOVEMENT AND SOLAR POSITION – The first thing to understand is the sun’s path across the horizon at any given location. A building designed with careful consideration of these elements can take advantage of natural daylighting, passive heating, photovoltaic energy generation and even natural ventilation. However, careful consideration is necessary to ensure these potential advantages don’t work against building efficiency by producing glare or overheating.
ORIENTING THE BUILDING ON SITE – The term ‘orientation of a building’ usually implies the direction that the facades face. Irrespective of climate, there are advantages for the main façade to face north or south, rather than east or west. This is because the sun is low in the sky in east and west, even in summer, which makes shading difficult. On the other hand, north facing windows receive direct sunlight only in high summer, while a south facing façade can be easily shaded by small overhangs, due to the high angle of the sun.
DESIGN ELEMENTS AND TECHNIQUES – Various design elements and techniques can be adopted to maximise the usage of natural light, ranging from light-wells, light shelves, external reflectors, light ducts, atriums and reflective blinds. All these elements and techniques have the potential to create a signature design element for architects and designers and also promote sustainability and lesser energy consumption.
UNDERSTANDING THE DEPTH OF BUILDING – It is commonly accepted that the depth of the daylight penetration is about 2.5 times the distance between the top of a window and the window sill. If a designer can place a most regularly occupied part of the room in this zone, the use of artificial light during daytime can be minimised.
DAYLIGHT HARVESTING – This is an energy management technique to reduce overhead lighting utilising the available ambient light, both natural and artificial, in any given space. It works by dimming or switching off lighting when sufficient ambient light is present or when a space is unoccupied.
BUILDING ENVELOPE – An effective building envelope conserves more energy and the wall-window ratio is key to effective building design. A 60:40% wall-window ratio gives a greater result. Also, designers can conserve a greater amount of energy by having effective thermal insulation, both on inside and outside wall surfaces, and appropriate selection of high-performance glass.