COLD CLIMATIC ZONE

COLD CLIMATIC ZONECompiled byHamza javed 031Harpreet kaur 034Himanshi gupta 124Praneet r.M. Singh 067Tshering CHODEN 118

PASSIVE DESIGNPassive design is design that does not require mechanical heating or cooling. Buildings that are passively designed take advantage of natural energy flows to maintain thermal comfort.When sunlight strikes a building, the building materials can reflect, transmit, or absorb the solar radiation. Additionally, the heat produced by the sun causes air movement that can be predictable in designed spaces. These basic responses to solar heat lead to design elements, material choices and placements that can provide heating and cooling effects in a building.

Passive heatingTwo primary elements of passive solar heating are - South facing glassThermal mass to absorb, store, and distribute heat There are three approaches to passive systemsdirect gain, indirect gain (trombe wall)isolated gain.

Passive CoolingPassive solar cooling can reduce or even eliminate the need for air conditioning in homes. Cross VentilationWing WallsThermal ChimneyOther Ventilating Strategies

Shimla- cold climatic regionThe Shimla weather during summers are very enjoyable as the weather remains mild and one needs to wear light cotton garments and light woollen clothes.The Shimla climate during the winter is very chilling where the temperature swings between a maximum of 8C to a minimum of 0C and may even dip down below that level too.It extends from December to February. The climate of Shimla in winter ishighly dominated by the cold winds from the Himalayas. Snowfall takes placeduring the end of December when the cold becomes unbearable.

CASE STUDIESHIMURJA BUILDING ,SHIMLAMLA HOSTEL, SHIMLA

HIMURJA BUILDINGLocated at Shimla at an altitude of about 2000metres above mean sea level in the middle Himalayas.The sharp sloping site provides a classical situation in a hilly urban context for a building within a large commercial complex that thus suits against the mountain for the lower three floors and inevitably has a deep plan.

DESIGN FEATURESThe climate requires building to be heated almost throughout the year.DAYLIGHT AND HEATINGAir heating panelsINSULATION AND WINDOW DESIGNDouble glazed windowsSolar chimneysolariumRENEWABLE ENERGY SYSTEMSSolar water heating systemSolar photovoltaic system

DAYLIGHT AND HEATING

Both the plan and the 3d form of the building allows maximum penetration of sun, maximizing both solar heat gain and daylight.Air heating panels designed as an integral part of the southern wall panels provide effective heat gain through a close connective loop.

Air heating panelsDistribution of heat gain in the entire building is achieved through a connective loop utilizing the stairwell as a means of distributing heated air through the principle of buoyancy.Since solar heat gain raises the internal ambient temperature above the comfort range in summers even though the outside conditions are quite comfortable, ventilation is an effective strategy for summers for dissipating internal heat build up.To optimize ventilation, the connective loop is coupled with solar chimneys designed as an integral part of the roof.Specifically designed solarium (sun space) is built as integral part of the southern wall to maximize the heat gain.

Insulation and window designGood insulation of 5cm thick glass-wool and minimum fenestration (only in toilets) on northern exposure prevents heat loss.Infiltration losses are minimized through weather-proofed (with no thermal bridges) hard plastic windows.Double glazing heat loss from glazing without creating any internal condensation.

Renewable energy systemsThe photovoltaic system of 1.5kWp meets the energy demand for lighting whenever required. Artificial lighting is seldom required ( except during dark sky conditions sometimes in winters) in the south oriented spaces, which are well day lit during working hours.Roof mounted solar hot water system has been used in the building. The water is circulated through radiators for space heating specially in the northern spaces.

MLA HOSTELThe MLA (Member of Legislative Assembly) Hostel is located in the cold and cloudy climatic zone, the design has to primarily cater to the difficult winter months. Heating and day lighting have been considered while designing. Use of certain energy-efficient and renewable energy devices has also been suggested to increase the overall efficiency of the building.The whole complex comprises four blocks. The blocks are regular RCC-framed structures with brick in-fill walls. The blocks are oriented south.

Key Sustainable FeaturesSolar orientationAirlock after staircase landing to prevent heat loss and infiltrationEnhanced thickness of external wallHeavy curtains and carpeted floors to add to thermal comfortAdequately sized overhangs to maximize solar access in winterRoof and wall insulationTrombe wall and sunspaces at appropriate locationsAppropriately sized and detailed glazing systemGlazed atrium over staircaseInnovative heating systems using solar water and air heatersBetter weather stripping to reduce infiltrationIntegrated food warmer with the structureRoof mounted solar water heaterLow wattage electric radiating panels for back-up heating

Revised layout

The buildings are oriented due south +15 degrees for direct solar gain. They are spaced apart so as to eliminate shadows of one building falling over the other., even for the longer winter shadows.It was proposed that all bedrooms be south-facing to avail of the benefit of south exposure.Separate air locks would have prevented heat loss, and decreased the rate of infiltration. This suggestion could not be accommodated due to lack of space at the entrance.

Thickening of external wallThe thickness of the existing external wall was changed to at least 9 or 12 of stone as the existing 4.5 brick wall was inadequate for weather proofing.

Overlapping curtainsWell sealed heavy curtains were used to act as a thermal mass and to prevent heat loss.Carpeted floorsCarpeted floors provide insulation and improve the general level of comfort. They should preferably be dark in colour when adjacent to south windows.

Small overhangsSmall overhangs helped to increase the amount of sunshine entering the building, while ensuring that no summer overheating took place.The primary purpose of the shades was rain protection.A 23cm overhang can adequately protect a 1.2m high south facing window in peak summer while providing adequate rain protection.

Roof insulationRoof insulation helped to preserve temperatures inside the building and prevented heat loss from the top floor.Rockwool insulation was provided above false ceiling.

Wall insulationWall insulation could be either insulation or a cavity wall and would help in roof insulation. Eventually, a Rockwool blanket/thermacol sheet was used in the walls behind the paneling.Insulation was suggested on all walls except south because it was found out that the north, east, and west walls are net loser of heat.

SunspaceThe existing balcony can be made into a sunspace resulting in increased heating especially during the winter months. This suggestion could not be incorporated in blocks 1 and 2 because of prior structural limitations, but has been introduced in blocks 3 and 4.

Reduction in north glazingSince solar heat gain through north facing windows is negligible, glazing on the north increases heat loss to the ambient.This is rectified by reducing the amount of glazing in the north, and providing double glazing in the essential windows.

Plastic/ timber framesSince plastic and timber have a lower conductivity than steel it is advisable to use them for joinery to reduce conductive heat loss to the outside.

Steel would aid heat transfer and would work against attempts to retain heat inside the building.

Remote heating of north bedroomThis idea was proposed to trap heat on the south wall and transport it to the north bedrooms.Small Trombe walls below and on the sides of the kitchen window trap the heat which is conveyed through a duct to the northern bedrooms.A small fan can be used to assist air movement. Better weather proofingThese measures at the openings helped to reduce infiltration.Rubber stripping at the junctions of shutters and frames and below doors helped in sealing the cracks.Keeping windows closed, and immediately replacing broken panels especially during winter months would help reduce infiltration considerably.

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