Ar. Yatin Pandya of Footprints E.A.R.T.H writes about how conventional wisdom can help in resolving architectural fallacies and energy conservation.
A sustainable design focuses on minimising the negative environmental impact of buildings by efficiency and by making optimum use of materials, energy and development space. In the recent past the definition of green building has undergone a drastic change. With urbanisation and growing population, today major energy requirement of modern buildings are fulfilled by technological advancements, which in turn is resulting in maximum utilisation of energy resources instead of conservation. Ironically, India ranks fifth in the energy requirements, of which buildings account for nearly 40% (residences 23.4%, commercial buildings 6.6%, industries follow next with 36.5% and agriculture 30.7%). In terms of utilisation of energy, during the daytime a building utilises 92% of energy, which is spent in cooling (60%) and day lighting (32%). On the other hand, residential buildings consume 64% of energy. This makes it quite logical for us to prioritise cooling and day lighting to be prerequisite of sustainable designs.
We look at technological advancements as key to comfort but we often forget to address energy-intensive technologies. To resolve this, we must resort to conventional wisdom which not only helps in conserving energies but also fulfils the energy requirements in a sustainable manner.
The traces of conventional wisdom can be found in past, when there were full wall openings or undeterred views which was resolved either by perforated jaali walls in Rajput or during Islamic regime or a stained glass opening as observed during colonial phase. These techniques discouraged ingress of heat and provided extended views from inside out while offering privacy. Smaller apertures of jaali create microclimate features to induce velocity of air and cooling of air particle throughVentury and Bernoulli’s principle respectively.
Six basic architectural resolutions
The following resolutions play a key role alongside conventional wisdom to resolve architectural fallacies.
Seating and location: This has severe implication through orientation, exposure and impact of natural forces. In western hot arid zones of India orienting building with its longer faces to North-South compared to East-West can reduce solar radiation and exposure and thereby the energy demands to nearly half.
Form and Mass: This has potential for confronting natural forces as well as to benefit from mutual shading and scaling. As a thumb rule, exposure levels and thereby energy demands can be reduced in a building in hot-arid zone up to ten percent by optimising on volumes of the building in areas such as passages, verandas, toilets, alcoves etc. By adding a floor with reduced radiation from the top it gets reduced to about 20%. It is nearly halved by attaching the building from sides as well as stacking floors above.
Space organisation: This governs the extroversion or introversion, compactness or fragmentation, along with directionality and exposure value of the architecture. For example traditional buildings from hot arid regions have been compact, stacked and attached in their form, and have been interspersed with multiple yet small scale courtyards to reduce heat gain.
Elements of Space making: This forms the essential syntax of the architecture and thereby its interactivity with external conditions. For example pavilion-like structure with prominence of inclined roof form versus lightness-often absence of wall is the syntax of hot-humid climate. Conversely predominance of wall and subjugation of roof is the grammar of hot-arid climate zone.
Material and Construction techniques: This is vital in setting forth the chemistry of building with external elements through its thermal coefficient, material properties and dynamics of its physics. If sunburnt clay block is taken as a unit of energy demand of material, cement is nearly ten times energy intensive, steel thirty times, PVC 120 times and aluminium 160 times.
Finishes and surface articulation: Although seemingly micro, the skin rendering turns out to be the first aspect of building to negotiate with environmental conditions. As the first line soldier it takes the maximum brunt of the vagaries of nature. Dark versus white or very light colour rendering with glossier surface can create up to five degree temperature difference within its high reflectance value.
Case Study -1
The best example can cited of my project The Environmental Sanitation Institute in Gujarat which involves application of conventional wisdom to conserve energy. The project combines solar passive as well as solar active strategies and accommodates ventilated cavity wall construction for active insulation, ferrocement shell roofs for optimisation of structural stresses and reduced material consumption, vaulted roof forms for volume optimisation within. Along with this, over two million litres of rain water harvesting in cistern, percolating well as well as an open pond, recycling of waste through natural plant based root zone system, generation of methane gas through bio-gas digesters attached to the toilet waste, use of low water sanitary pans, fertilising of the compost, saving of finishing material and maintenance through exposed brick external surfaces, frameless fenestrations, louvered-glazed and perforated window combinations for light-view and ventilation, interactive courtyard and terraces for outdoor use, solar active applications as water heater, solar cooking (100 persons), solar photovoltaic panels producing electricity are some of the nuances applied at the institute that provides training in the areas of alternative low-cost solutions for rural sanitation.
Case Study -2
Another example can be taken of Manavsadhna Activity Centre which is a very different interpretation of sustainability. A community centre in a squatter settlement, it uses the building components recycled from the domestic and municipal waste. The entire building is the demonstrative application of waste recycled products indigenously developed. Recycling the waste answers the call of environment through reduced pollution, empowers and employs the poor through value addition processes, and helps towards affordable and durable housing. The building uses fly ash bricks, dump fill, site waste, residue bricks, stabilised soil blocks, wood crate panels, glass bottles and waste filled plastic bottles etc. for walling options. It uses cement bonded sheets with clay tiles, stone slabs, glass-plastic bottle filled filler slabs etc. for the roofing, wrapping waste reinforced F.R.P., oil tin container panelling, wood crate panelling etc. for the doors and windows and in parts waste-fly ash-china mosaic tiles and blocks for flooring. These become live demonstrations for the urban poor to emulate in their homes.