CLIMATE CHANGE - A PHENOMENON CLIMATE “A change in climate which is attributed directly or indirectly to Region with certain conditions of human activities that alters thetemperature, dryness, wind composition of the global , light etc. atmosphere and which is in addition to natural climate variability observed overTROPICAL CLIMATE comparable time periods.” Heat is the dominant problem. Annual mean It implies that climatic change is temperature is not less attributed to human activities than 25 degree C directly or indirectly.
CLIMATIC ZONES HOT-ARID ZONE • High diurnal variation WARM • High seasonal HOT ARID variations with HUMID extremely hot summers and cold winters • High insolationTEMPERATE COLD • Low rainfall and water scarcity ZONE • Bright cloudless sky Summer winterClimatic variable time mean maximum mean maximumAir temp(deg.C) Day 43-49 58 27-32 - night 24-32 10-18RelativeHumidity (%) 10-55 -precipitation 50-155 -
CLIMATIC PARAMETERS HUMIDITY ANDAIR TEMPERATURE PRECIPITATIONSOLAR RADIATIONAND INFLUENCE AIR MOVEMENTOF SKYCONDITIONS
VULNERABILITY OF SETTLEMENTS TO CLIMATE CHANGEI. Housing & shelter Sectors attributed directly toII. The surrounding community,neighbourhood,villag human settlements and e or relevant social unit in which vulnerable to climatic change individuals live,III. The supporting physical • Health infrastructure (e.g. water & • Changes in social and sanitations services physical environment &communication links) • Loss of biomassIV. social &cultural services (e.g. • Drought or water storages Health services,education,police • Floods protection,recreational services • Tropical cyclones etc.,) • Sea level rise
SITE ASSESSMENT SITE SELECTION SITE ANALYSIS SITE DEVELOPMENT
SITE SELECTIONIt is governed by adjacent land uses, access to publicinfrastructure, approval and permitting requirements, cost ofland & construction, microclimate, ecological patterns andresources. BASIC RESOURCES THAT MAY BE DOCUMENTED AT COMMUNITY LEVEL • Wetlands • Floodplains • Moderate &steep slopes • Groundwater resources and aquifer recharge areas • Woodlands • Productive farmlands • Significant wildlife habitats • Historic, archaeological & cultural features • Scenic view sheds
Where the proposed use of the site isAnalysis of the building site which predetermined, and site analysis and siteincludes the assessment of its planning arc concerned withbetter features as well as itsconstraints and liabilities determining, how best the proposed use can be fitted to the siteLand planning projects in mountainregions require data on topographic SITEslope, elevation & aspect whereasthis attribute may be insignificant on ANALYSISa level terrain Whenever a site is to be developed for aIt may entail different kinds of particular building program, two sets ofevaluation i.e., information factors have to be considered.contained in site’s physical, SITE FACTORS - those relating tobiological and cultural attributes. the characteristics of the siteThese attributes influence the USE FACTORS - those relating tosuitability of a site for the proposed the proposed use of the site, i.e. theuses. building program
SITE INVENTORYPhysical attributesThe purpose of site inventory is the quick assessment of the site to: • Identify potentially significant site assets & liabilities • Develop a base map for land planning & design Physical AttributesTopography Soil Climate Precipitation Temperature Wind Elevation Slope Aspect
Site inventory characteristics Building design elements Site design elementsGeographical latitude and • Building layout for solar • Location of green andmicroclimatic factors such as orientation paved areaswind loads • Location of windows , • Selection of vegetation and entrances, and loading integration with the native docks landscape • Location of air inlets • Bio-diversity • Architectural elevations • Use of landscape elements • Surface to volume ratios such as buffer zonesTopography and adjacent land • Building proportions • Gravity fed sewer linesforms • Wind loads • Land fillings • Architectural elevations • Natural site features for • Drainage strategies rain/storm water drainage • Location of groundwater detention pondsSolar access • Building position for day • Location of energy efficient lighting , photovoltaic and features such as solar solar passive techniques ponds • Construction of walls • Placement of selective • Selection of building species of trees such as materials and finishes deciduous trees n the south side
Site inventory characteristics Building design elements Site design elementsGeologic and seismic data • Foundation type Structural considerations for • Structural specifications site landscaping , such as retaining walls , fixed seating, etc.,Air movement patterns • Placement of wind towers Site layout of building • Location of fenestration on structures to trap wind for the basis of pressure ventilation differentials , passive solar cooling designSoil types , textures and load • Foundation design and • Site grading proceduresbearing capacity location that minimize erosion • Plant selections as per soil typeParcel shape and access with Planning for the capacity to Making the potential accessadjacent land uses and accommodate the proposed points , which do not burdenbuildings development the lower density or adjacent land useNeighboring or proposed Design flexibility for future Location of utility andfuture developments extension infrastructure for future extension.
SITE DEVELOPMENT• Excavation and grading keep to an SLOPES (Earth Cut Or Fill) • Do not exceed the angle of repose of the absolute minimum. soils being graded or placed (the steepest• Balance the on-site cut and fill. Off- angle at which the slope remains stable). • A slope of 1on 2 maximum (I foot vertical site borrow or disposition is rise for 2 feet of horizontal distance) is recom-mended for mulched or planted expensive. embankments.• Protect trees and established • A slope of 1on 3 maximum is preferred for lawn areas to facilitate mowing. ground covers. Remove and • Place fill material in uniform layers of 6 to 8 inches of loose material. stockpile the topsoil. • Allow for soil shrinkage (or swelling in some• Avoid working the soil when it is instances); 3 to 5 percent shrinkage is normal in compacted fills. wet, powder - dry, or frozen. • Provide mechanical compaction. Natural• Provide positive surface drainage compaction by the eventual settlement of loosely placed soils is seldom uniform or away from buildings to swales, complete. • All fills should be compacted fills, placed on gutters, drain inlets, or outfalls. prepared benches cut through topsoil and• Re-establish ground covers without overburden. • Thrust benches and positive drainage must delay. Unprotected soils cause be provided at the base of major fills. erosion and siltation.
Sun-orientation• The orientation of a building is influenced by the amount of solar radiation falling on different sides at different times.• Buildings are best arranged in clusters for heat absorption, shading opportunities and protection from east and west exposures.• The larger building dimension should face north and south (generally, west orientation is the worst: high air temperature combined with strong solar radiation) .• The optimum orientation for any given location has to be determined in order to achieve the most satisfactory distribution of total heat gain and loss in all seasons. At high altitude enough heat gain for passive heating should be possible.
ROADS AND DRIVEWAYS PARKINGIn planning the approach drive orroadway consider: • Sight distance: provide sufficient • Allow a normal stall width of 8 feet 6 horizontal and vertical sight distance inches minimum to 12 feet to give 10 second minimum maximum; 10 feet is a comfortable observation time at permitted approach speed. average. • All-weather and nighttime • Stall marking: While a single divider drivability, stripe will suffice, two 3-inch lines, • Economical length and minimum 12 to 16 inches on cen-ter with a half landscape disruption circle at the aisle end, is recom-mended. • For an approximate parking compound capacity calculation, allow 300 square feet of paved parking area per standard car, plus approach ramps, distributor loops, planting medians. turnabouts, collector walks, and buffer areas.
DESIGN FOR HOT-ARID ZONES• Minimal sun-exposure in summer is necessary and therefore compactness and shade are the main principals for building in hot-arid zones.• compact planning for groups of buildings is required in order to give shade to each other and reduce the surface area exposed to solar radiation.• Arcades, colonnades, cantilevered buildings or building components, membranes and small enclosed courtyards are traditional responses to the climate.• Air circulation can be improved through wind channelling in shaded narrow streets in the direction of the main wind.• The grouping of buildings and alleys or lanes should allow for proper ventilation or even increase the airflow.• The location near a water source and the incorporation of vegetation is most important.
1. Grid diagonal to east-west axis 2. Narrow, zigzagging alleys• The grid pattern maximizes radiation throughout its straight streets, but by • Winding or zigzagging narrow alleys orienting the grid pattern diagonally to receive minimum radiation, reduce the the east-west axis, the sun exposure and effect of stormy winds, establish shade is better distributed on the streets; shaded spaces throughout the day such a grid still supports the dynamic which provide a cool and comfortable movement of air. More important, microclimate and also stay relatively however, is the form of alleys and warm during cold nights and in winter. buildings.
BLOCKED STREETS AND ALLEYSStreet orientation and housing patterns are significant and must beplanned carefully. Straight and parallel streets open the city to windventilation. Storm effects can be reduced by blocking streets. Two-story buildings with closed patios open to the sky will maximizeshade, minimize radiation, yet still retain ventilation and reduce theeffects of stormy winds. Buildings should be attached (cluster) toreduce exposed surfaces.
URBAN HEAT ISLAND Heat island refers to any area which is hotter than the surrounding area. CAUSE SOLUTIONS TO REDUCE UHIE• Improper planning of the site creates “heat island effect”.• main cause of the urban heat island is • Limit the area of hard surfaces modification of the land surface by urban like paved roads etc. development which uses materials (such • Shading of paved areas using as asphalt, tar etc)which effectively • green cover retain heat and also by the waste heat • Use of Light colour concrete produced by the buildings and vehicles.• Effects of UHI • surfaces• Decreases air quality by producing air • Open grid pavement pollutants like ozone • Materials with high reflectance• Decreases water quality as warmer water effects the ecosystem.
HARVESTING ENERGY FROM ASPHALT PAVEMENTS AND REDUCING THE HEAT ISLAND EFFECT This is a concept of using a piping network below the surface of asphalt pavements to flow an appropriate fluid, to reduce the temperature of the asphalt pavement,reduce Urban Heat Island Effect, and use the heated fluid for different end applications such as heating, power generation or refrigeration. The reduced temperature will extend the life of the pavement, while the reduced temperature of the near surface air will lead to savings in energy consumption of adjacent buildings and improvement in air quality.
WIND SHADOW EFFECTWind when meeting an obstruction in itspath creates pressure on windward andsuction on leeward path ..as a resultbuildings on leeward path faces poorventilation so they are placed instaggered forms or at six times theiractual heights.If buildings are laid out on a regular grid, thebenefit of wind may be lost altogether. If buildingsare staggered, and preferably spaced apart, thenthe flow of air may bemaintained, and the wind shadow reduced.
Landscape Elements for Microclimate Control General landscape treatment to create• Landscaping can be used to comfortable micro climate • . control several aspects of the microclimate. The climatic variables that can be regulated include solar radiation (sol-air temperature), air temperature, wind speed and direction, relative humidity and glare.• Landscaping elements can be grouped into hard landscaping elements and soft landscaping elements
HARD LANDSCAPE ELEMENTS Steps and pavingAir crossing hard reflective or absorptive surfaces like parking lots and sidewalks is warmed.The choice of the surface finishing, material and construction of steps and paving can play asignificant role in the reduction of ground temperature. Walls and fences• Walls are used to deflect the wind, and they can be used to channel the wind. Walls are usually solid, while fences are made from stakes, rails, wire, netting, et c. Fences thus allow some wind to flow through them, even when they have climbers. Slopes and barriersThe use of slopes and barriers to direct airflow can be very effective on sites with significantvariations in the topography. Stones and boulders Stones and boulders can be arranged to direct airflow and to provide shade. SOFT LANDSCAPE ELEMENTS Trees and shrubs• Trees and shrubs are the most significant in the provision of shade and the control of relative humidity and air movement.• They contribute thermal comfort than any other element.• Ventilation is affected by plant materials.• air passing through trees and plants will be cooled.
HOT-ARID REGIONS TRELLIS• In these regions landscape elements should equalize temperature by avoiding hot winds and to retain existing moisture.• Southern exposure should be treated with landscaping to block rays of sun.• Tall high crown trees such as palm ,eucalyptus are used as sun screens• Use of trellis on south facing structures also causes shading and cool winds.SOUTH FACING TREES BLOCKTHE DIRECT SUN RAYS ANDPROVIDE SHADE TO ADJACENTSTRUCTURES
• Western exposures are vulnerable to harsh glare so groundcovers cut reflection and cool ground air.• Eastern faces can be controlled by planting bushes or low trees are preferred.GROUND COVER IN CHECK BOARD PATTERN USESNONREFLECTANCE MATERIALS SUCH AS WOOD,CHIPS ETC.ITADDS COLOUR AND DESIGN,DOES NOT REFLECT HEAT ANDLIGHT, CONSERVES MOISTURE AND ELIMINATES DESERT LIKELANDSACPE.
POOLS AND PONDS A good example is the Bahai Temple at New Delhi. This is a complex concrete shell structure which is a place of assembly, but does not utilise air-conditioning, even though a hot dry wind blows through the area. The wind is funnelled over embankments over standing water which is below natural ground level. It then passes through the openings around the base of the dome, and rises up through the interior.water bodies are used forhumidification and evaporativecooling.cool pools, if large enough, canhave a significant effect. If movingair can be funnelled through thesepools which is out of the directsun, it will lose some of its heatbefore reaching the building.
“ All architecture is shelter, all great architecture is the design of space that contains, cuddles, exalts, or stimulates the persons in that space” Philip Johnson • Chaitanya korra 090-158 • Rachana 090 -160 • Ravali 090-172 • Mehar kumar 090-176 • Manogna 090-175