Design with the sun in mind
The building plan must work with the sunlight, and locate spaces accordingly.
Recently the Jantar Mantar, a solar and astronomical observatory at Jaipur built by Sawai Man Singh, made news by getting into the UNESCO World Heritage Sites list. Many parts of the ancient world boast of historic structures designed to calculate climatic data, wherein the sun dial finds a place. Even today, some science students prepare sun dials for annual school exhibitions. The elderly in a village predict the time of the day nearly correct without any wrist watch. Local and vernacular houses never opened a window to certain directions, and where possible the village streets followed specific orientations to ensure that the majority of houses faced fewer directions.
We are discussing a traditional knowledge system, centred around the Sun – a system which resulted in mind-boggling applications ranging from rituals to rhythms; cosmic studies to cultivation; design matters to social philosophy. There are many temples where sunlight is brought into the core of the structure on certain days of the year, calculated so precisely hundreds of years ago. People realised how to understand sunlight, and invite it or avoid it accordingly. With no mechanical or artificial modes, they evolved shelters which stayed cool during summers and warm during winters.
Well, the point here is not to simply praise our past, but to wonder where we have lost that knowledge. With a wealth of buildings behind us, why are we building such that we get roasted inside during the summers? The answer is simple – we have ignored designing with the Sun.
India being a tropical country gets a great share of sunlight, which can be directed judiciously into the building to get all the daylight we require. Nowadays there are many computer softwares like ‘ecotect’ that advice about sunlights and shades, while in the past there were climatic data tables with sun chart diagrams and solar angles. One can apply the simple formulae using the solar positions called as altitudes and azimuths to know the direct solar incidence on a window. According to such computerised or manual calculations, one can decide the location and type of shading required.
Our elders have already researched about summer solstice of June 21 and winter solstice of December 21 to enumerate how one fixed window or shading device does not work best round the year. As such the challenge is to ensure the building plan works with the sunlight, i.e. locating spaces accordingly. Rooms requiring light face the solar directions, while those which need less light are kept away. Also, rooms that can block the heat gain are placed to cut the unwanted solar light.
However, planning alone cannot provide all solutions of letting in light without heat. Shading becomes an essential mode of designing for sunlight, a mode that demands more of our attention.