SUSTAINABLE SITE RESPONSIVE ARCHITECTURE

INTRODUCTION As we all understand, sustainability is about being able to

continue with the current ways of doing things, consumption patterns, and lifestyle etc. without compromising on similar future needs.

However, sustainability is not really an original idea; it’s like old wine in a new bottle.

Along the journey in time, established ideas have got diluted or lost somewhere. Moreover through the changing eras, a lot of new issues have been thrown up and it is necessary to respond to those as well. The major impact is that of depleting resources as against the increasing needs and the consequent ecological footprint that is getting threateningly large and completely unmanageable.

That is why we have to embark on this active agenda of pushing sustainable practices.

APPROACHES Sustainability could have two basic approaches:

o Naturalistic or the passive or o Active or artificial.

The latter is energy driven; and can be seen largely as what could be termed as “second level” or sometimes even as remedial measures. Whereas the earlier one, is simply smart design, planning and detailing; more importantly, done at the right stage.

THE INDIAN CONTEXT:

As Indians, we have a sustainable outlook towards life in general; we have been living sustainable lives since generations. This bank of wisdom is our legacy today and the onus is on us to see how it can be taken forward.

This outlook has embraced all walks of life, be it alternative medicine, social sustainability or sustainability of the built environment.

RICH AND DIVERSE VERNACULAR TRADITIONS:

Our rich vernacular tradition actually starts from the natural settings of the site/city, and responds to metaphysical concerns, climate, local skills/materials and appropriate technology.

More importantly, it is a passive approach and thus less energy intensive; these are proven technologies and often scalable.

Pictures of jalli wall, courtyard houses, water tanks, orientation

THE VERNACULAR…… IS IT SUSTAINABLE ………? The “vernacular architecture” could be understood as the

building traditions which have been developed by people over generations and often built by themselves.

These are tried and tested practices which have actually sustained the ravages of time; they have been handed down through generations. They rely on passive measures, by and large and respond to the context.

Basically, it is “architecture without architects”. The basis of vernacular is that it responds to several

contextual aspects: o Climate, Place, Culture, Materials, Local skills and

also

o Maintenance, Durability and Metaphysical aspects

The premise is that the vernacular tradition was extremely sustainable in every sense of the word… let us see how through some examples

ENERGY AND ITS ASPECTS: LIGHT AND VENTILATION

Light: Most of our buildings had grills etc and fenestration/façade engineering done to control and manipulate light by means of devices like jalis or double windows with wooden louvers etc.

A lot of religious buildings like temples and masjids also used similar strategies to control light and air movement.

Water: More lavish buildings like palaces and forts made ingenious use of water to cool the building envelope; the walls would have water pipes embedded inside to cool down the masonry walls; the water was cooled naturally

by making it run over surfaces and exposing it to the atmosphere.

Ventilation: Wind scoops also allowed the entry of breeze into the hot desert zones; micro climatic modifications include the introduction of dripping water by installing a pot at the top of the scoop.

COURTYARD ARCHITECTURE

Courtyard architecture: The courtyard home was the prevailing Indian planning model before the advent of western ones. It was very versatile; as a climatic device, as an outdoor cooking/dining, sleeping/living area and for festivities etc.

It was adaptable to any climate across Indian cultures and geographies. That explains its survival.

Proportions: A hot humid zone should have courtyards with more length and breadth compared to height where the basic climatic strategy is to cut out heat and provide air movement. A hot dry climate needs more height to provide shade. It allows cool air to settle down in the summer and allow outdoor living in the sunnier parts of the courtyard in winters.

LEARNINGS… Learnings from the vernacular that can be used in contemporary architecture

Make use of passive measures: Use planning devices like courtyards, suitable orientation, envelope design and appropriate detail elements like jalis, water bodies with responsive roof and fenestration design.

Make use of local materials without major modifications in their naturally occurring organic states to “complete the loop” along with the use of local crafts and skills.

Build to create structures that are largely durable and maintenance free.

Ensure resource optimization: Go for water harvesting and recycling, energy optimization by ensuring good daylight and ventilation, (using natural currents, with wind scoops, solar chimneys etc) space cooling/heating (using passive measures like geothermal energy or earth sheltered buildings)

Limitations: This architecture cannot be replicated the way it was built by our ancestors for the current population’s numbers nor for the urban high rise typology. However, its strength is that, it is adaptable to change; that probably explains how it has survived to date.

CONTEMPORARY SUSTAINABLE BUILDINGS

The Golconde, Pondicherry:

It is the first sustainable rcc building in modern India and perhaps the earliest one in the world as well. (1945) it is planned on vernacular traditions like climate sensitivity and radical economy by minimal resource consumption and uncompromising construction standards to get a durable, maintenance free building.

Passive strategies: The building allows air flow across the north south long facades; through the louvered external wall and the screened internal wall partitions of the residential quarters and out through its windows. The east and west have minimal exposure minimizing the solar gain.

Modern interpretations of the courtyard

SUSTAINABLE PLANNING

The sustainable planning could be classified under three broad sectors and sub-sectors within as follows.

Energy and indoor comfort-energy, comfort Water and wastewater—water, sewage, storm water Quality of built environment— solid waste,

pollution,ecology and geology, building material

ENERGYThe prime intent for sustainable planning is to enable the reduction of energy consumed by buildings, through proper transport planning in large neighbourhoods, site planning, and adopting climate-responsive design for buildings, in addition to using efficient lighting and space cooling.The three fundamental strategies adopted to optimize energy performance in a building.

Reducing energy demand Maximizing system efficiency Optimizing the usage of renewable energy

Integrated Green Design (IGD) approachThe Integrated Green Design (IGD) approach looks at a building in stages of its planning and design from the broader issues to the details. Each stage within the IGD approach fulfils one or more of the five ‘Green’ building imperatives.

STAGES OF PLANNING & DESIGNSustainable Site Planning

The IGD approach starts not from the site layout but from site selection. While not possible in all cases, wherever possible efforts must be made to choose an appropriate site for the proposed use of the building. This would result in less damage of virgin land and less energy expenditure in ‘developing’ a site. For buildings within large campuses, selecting an appropriate plot within is equally important.

AVOID NATURALDRAINAGE LINES- Especially important in sloped sites.Obstructing natural drainage lines would involve energy use to drain out storm water or risk site flooding

READY ACCESS TOEXISTING INFRASTRUCTURE- Electricity supply- Water supply- Public transportHelps reduce need for new infrastructure

Bank

Shops

COMPACT CLUSTER PLANNINGCluster based planning of the building blocks within campuses results in more compact utilities network, reduces damage to existing environment and promotes walkability. Sharing spaces, services and creating a medium-rise, high density development complements this.

LAYOUT AND DESIGN OF BUILDINGS SHOULD BE AS PER SOLAR GEOMETRY

Longer dimensions of buildings should face north and south (with a maximum deviation of 5º off north) and shorter dimensions should face east and west.

The southern sides of the plots should be shaded by deciduous trees. In case of high-rise structures, windows or façade should be shaded by in-built shading devices.

The east and west façades should be protected by using shading devices, vegetation or buffer spaces.

Courtyards should be oriented along east–west axis to capture maximum wind. To create cooler microclimate conditions, water elements should be provided along the wind paths.

One block shades the other

ORIENTATION OF BUILDINGS A building can be laid out and designed on the basis of sun

path and wind direction. A building designed according to solar path remains

comparatively cool in summers and warm in winters, thus obviating the need for artificial heating or cooling.

If oriented properly, a building receives comparatively less radiation, which results in lesser heat gains.

This reduces overall air conditioning requirement, which, in turn, saves energy.

Solar angle and altitude with respect to a particular surface vary with time, following a distinct geometry. This geometry can be followed while designing a building.

Proper layout and design of a building ensure that the building benefits the maximum from the wind so that there is no need for artificial ventilation and cooling.

Planned layout and design of a building make the building get just enough sunlight, without any glare.

Incorporation of shading devices can be planned in the initial stages of layout and design, which will lead to energy efficiency and add to the aesthetic appeal of the building.

High sun angle in summer on the south side. Hence easy to shade

Exposure variation summer / winter

Minimum radiation on the north side allowing large windows for excellent day lighting

Low sun angle in winter allows welcome solar access

Low sun angle, on east and west. Difficult to shade in summer

N

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June 21

Dec 21

As the sun moves from east to west and sun path is more inclined towards south, the north façades of the building do not receive direct radiation.

Solar angles are low in east and west, while high in south. In efficient buildings, the longer façade faces north and

south, while the smaller façade faces east and west. The radiation can be cut-off by using shading devices. Shading devices protect the building by obstructing the

vertical shadow angle and horizontal shadow angle, which are calculated from sun path diagram.

DESIGNING A SOLAR PASSIVE BUILDINGSolar passive architecture design strategies

Landscaping: Micro climate of a place can be altered by growing trees and vegetation. Roof gardens also reduce heat load.

Water bodies: Water has a moderating effect on air temperature. It has a high thermal storage capacity. Water evaporation has a cooling effect on surroundings.

Orientation: The amount of solar radiation falling on a surface varies with orientation.

Building form: Building form affects solar access and wind exposure as well as the rate of heat gain and loss through the external envelope.

Building materials and construction techniques: The energy content of a building can be reduced by using building materials that use low energy in manufacturing.

Building envelope: Building envelope components like walls, roof, windows, floor, and surface finishes are the key determinants of the amount of heat gain or loss and wind entering the building.

Thermal storage/thermal capacity: The heat storing capacity of building materials helps to moderate

Cooled wind is welcome

Wind for night ventilation is welcome

fluctuation in the indoor temperature by providing a time delay.

Thermal insulation: Insulation should be placed on the external side of wall and roof composition. Heat gain through roofs could be reduced by external insulation, green roof or use of high reflective material on roof top.

PASSIVE TECHNIQUES AND FEATURESThe first step to achieve passive cooling in a building is to reduce unnecessary thermal loads that might enter it. Usually, there are two types of thermal loads

(1) Exterior loads due to the climate. (2) Internal loads due to people, appliances, cooking, bathing, lights etc.

Proper zoning of different components and local ventilation of major heat sources can reduce the overall impact of internally generated heat loads. Table 1, summarises the basic cooling strategies that can be considered in a building design.

Depending on the weather, the thermal load enters into a building in three major ways:

(1) Penetration of direct beam sunlight.(2) Conduction of heat through walls, roofs etc.(3) Infiltration of outside air.

Passive cooling strategies need to be incorporated at the design initiation stage based on the planed organization of spaces in the building. This will ensure minimum HVAC loads

even if any active cooling systems are desired.

EVAPORATIVE COOLINGEvaporative cooling works well in the hot-dry climate as humidity is low in this zone. But water availability needs to be

checked

Water bodies outside or in courtyard, for cooling the air. Water bodies should be shaded to minimize evaporation losses.

Central wind tower system, with water spray on top. Useful for cooling double loaded corridors.Very acceptable method as humidity is welcome. Water availability needs to be checked.

Wind catcher

Usable space

Water spray

EARTH AIR TUNNEL SYSTEMThis system is viable if the ground below has good thermal capacity, for. E.g. soil with adequate water content. The design basics generally followed are (from various existing systems):- Pipe depth 4m- Pipe diameter 0.3 to 0.7m- Distance between pipes 3m centre-to centre- Pipe length

NIGHT VENTILATIONNight ventilation works well in this climatic zone as diurnal variations are high. In this process, buildings are ventilated at night when ambient temperatures are lower to resist heat build-up.

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Fresh air inlet Cool air into building

Day-time building heat gain

Night-time ventilation removes the heat gained during the day.

THERMAL MASS

LANDSCAPING FOR IMPROVING OCCUPANT COMFORT

PLANNING PLANTATION

Reducing water demand: Water demand for a landscape can be reduced, by planting, native and low water consuming plants. This is called xeriscape.Xeriscape design: Xeriscape landscaping incorporates seven basic principles, which help in water saving and conservation.Planning and design: A good design should be considered keeping existing structures, plants, budget, water requirement, and other factors in mind.Soil analysis and preparation: Before undertaking planting, soil of the area should be analysed. Organic matter should be added, if required.Appropriate plant selection: Native and drought-tolerant plants thrive the best in any given landscape. Growth rate and size of the plants, and light, water, and temperature needs should also be considered when designing the landscape.Mulching: A layer of non-living matter, or mulch, on the soil conserves water, reduces weed population, prevents soil compaction, and keeps soil temperature moderate.Watering: The greatest waste of water is applying too much too often. The key to watering lawns is to apply water infrequently, yet thoroughly.Efficient irrigation system: A combination of drip and sprinkler irrigation methods should be used for watering plants in a landscape.

DAY NIGHT

A building envelope with higher thermal mass will retard heat transfer from the exterior to the interior during the day. When temperatures fall at night, the walls re-radiate the thermal energy back into the night sky. Extensively used in traditional buildings in the region

REDUCING URBAN HEAT ISLAND EFFECT (UHIE) TO COOLBUILDINGS & SURROUNDINGS

Less trees on the north to let in daylight. More trees to the NW and NE to cut off summer radiation

Trees close to building on the west and closely spaced for shading

Trees prevent infiltration of dust laden hot summer winds

Preserve existing vegetation as they are a ‘free’ micro-climate modifier. Promote native species needing less water

Deciduous trees on the south side for shading in summer and solar access in winter

Trees act as noise and dust barrier

Roof surfaces absorb the highest heat

Paved surfaces absorb heat and the reflected heat is absorbed by surrounding building surfaces thus increasing heat gain

PROMOTING GROUNDWATER RECHARGEReducing paved areas and using pervious paving reduces UHI effect and improves groundwater recharge. Such paving can be used in walkways, pavements, vehicular roads within the site, ramps, etc.

Disadvantages of hard paving

Hard paving decreases infiltration of water during rains, increasing storm water run-off and causing water logging in low-lying areas.

Hard paved surfaces are generally coated with asphalt and concrete, which absorb solar radiation and raise the temperature of the surroundings. This leads to ‘heat-islands’ in built-up areas, increasing the use of air conditioners and power consumption in general.

….IGD 29 to 31….

Use roof finishes with high albedo

Shade parking area & pavements, through pergola, vegetation, photovoltaic’s etc.

Trees for noise & dust buffering

Increase soft paved area

Light colored wall surfaces will absorb less heat

Concrete grid paver

Sand compact sub-base

Gravel

Compact sub-soil base

Pervious paving