High Performance Buildings in Cold Climates

8/2/2019 High Performance Buildings in Cold Climates

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SUBMITTED BY-

PRATISHTHA SHARM

086451378

GUIDED BY-

MR. JATISH BAG



Introduction

Objective

Scope

Approach Methodology:

Literature Review

Case study

Conclusion Timeline

References

5/12/2011 1High Performance Buildings In Cold Climate

Solar Passive Design Building, Himachal PradeshState Government Secretariat, Shimla






Buildings, as they are designed and used today, contribute to seriousenvironmental problems because of excessive consumption of energy and other natural resources. The close connection between energy usein buildings and environmental damage arises because energy

intensive solutions sought to construct a building and meet its demandfor heating, cooling, ventilation, and lighting cause severe depletion of invaluable environmental resources.

However, buildings can be designed to meet the occupant’s need for

thermal and visual comfort at reduced levels of energy and resourcesconsumption. Energy resource efficiency in new constructions can beeffected by adopting an integrated approach to building design.




Construction sector contributes to nearly 10% of India’s GDP and growing at about9 -10%.

Energy demand increasing (30% of totalelectricity consumption is inresidential/commercial sector).

Domestic water consumption is 30 billionm3 and projected increase to 111 billion

m3 by 2050.

Construction and building wastes poseserious environmental threats.




To understand the need for energy efficient buildings.

To achieve a practical approach to highperformance/ energy efficientbuildings.

To understand the methodology anddifferent ways of achieving a highperformance building in cold climates.

To understand the importance of highperformance buildings in these times

when the natural resources are gettingextinct.


Himurja, Shimla



To find further resources andtechniques that add to the efficiency of a high performance building.

To use building envelope and

orientation for increasing the energy efficiency of a building.

To let people understand the need of the high performance building.


MLA Hostel, Shimla



The primary steps are as follows:

Incorporate solar passive techniques in a building design to minimize load onconventional systems (heating, cooling, ventilation, and lighting).

Design energy-efficient lighting and HVAC (heating, ventilation and air-conditioning) systems.

Use renewable energy systems (solar photovoltaic systems / solar water heatingsystems) to meet a part of building load.

Use low energy materials and methods of construction and reducetransportation energy.







LITERATUREREVIEW




Architects can achieve energy efficiency in the buildings they design by studyingthe macro and microclimate of the site, applying bioclimatic architecturalprinciples to combat the adverse conditions, and taking advantage of the desirableconditions. A few common design elements that directly or indirectly affectthermal comfort conditions and thereby the energy consumption in a building are

listed below: Landscaping

Ratio of built form to open spaces

Location of water bodies

Orientation

Planform

Building envelope and fenestration


Tabo Monastary Rest House



Building orientation is a significant design consideration, mainly withregard to solar radiation and wind.

In predominantly cold regions, buildings should be oriented tomaximize solar gain; the reverse is advisable for hot regions.

In regions where seasonal changes are very pronounced, both thesituations may arise periodically.

For a cold climate, an orientation slightly east of south is favored(especially 15° east of south), as this exposes the unit to more morningthan afternoon sun and enables the house to begin to heat during the

day. This has been amply demonstrated in the MLA hostel building at

Shimla.







The volume of space inside a building that needs to be heated or cooled and

its relationship with the area of the envelope enclosing the volume affects the

thermal performance of the building.

This parameter, known as the S/V (surface-to-volume) ratio, is determined by thebuilding form. For any given

building volume, the more compact the shape, the less wasteful it is in gaining/

losing heat. Hence, in hot, dry, regions and cold climates, buildings are

compact in form with a low S/V ratio to reduce heat gain and losses respectively.

Also, the building form determines the airflow pattern a round the

building, directly affecting its ventilation. The depth of a building also determines

the requirements for artificial lighting - greater more the depth, higher

the need for artificial lighting.




The building envelope and its components are key determinants of the

amount of heat gain and loss and wind that enters inside. The primary elements

affecting the performance of a building envelope are

(a) Materials and construction techniques,

(b) Roof,

(c) Walls,

(d) Fenestration and shading, and(e) Finishes.




Walls are a major part of the buildingenvelope and receive large amounts of solar radiation. The heat storagecapacity and heat conductionproperty of walls are key to meetingdesired thermal comfort conditions.

The wall thickness,material, and finishes can be chosenbased on the heating and coolingneeds of the building.

Appropriate thermal insulation andair cavities in walls reduce heattransmission into the building, whichis the primary aim in a hot region.


230mm brick wall with 12.5mm plasteron both the sides

Conventional Building, Shimla



North facing glazing is ideal for cooltemperate climates. It allows maximumsolar access in winter and can be easily shaded in summer.

In cool temperate climates: Maximize north facing glazing with solar

exposure (especially in living areas). [See:Passive Solar Heating]

Minimize east & west facing glazing.

Use adjustable shading. Minimize south facing glazing.

Use insulating glass and frames and/orsnug fitting insulating drapes with sealedpelmets.


Insulating glass unit with low-e



A trombe wall is a thermally massive wall

with vents provided at the top and bottom.It may be made of concrete, masonry,adobe, and is usually located on thesouthern side (in the northernhemisphere) of a building in order tomaximize solar gains.

The outer surface of the wall is usually painted black for maximizing absorptionand the wall is directly placed behindglazing with an air gap in between.

Solar radiation is absorbed by the wall

during the day and stored as sensible heat.The air in the space between the glazingand the wall gets heated up and enters theliving spaces by convection through the vents.


•Cool air from the rooms replacesthis air, thus setting up a convectioncurrent. The vents are closed duringnight, and heat stored in the wallduring the day heats up the livingspace by conduction and radiation.



Trombe walls have been extensively used in the cold regions of Leh.

• It is noteworthy that in buildings with thermal storage walls,indoor temperature can be maintained at about 15 oC when theoutside temperature is as low as -11 oC.

• Generally, thickness of the storage wall is between 200 mm and450 mm, the air gap between the wall and glazing is 50-150mm,and the total area of each row of vent is about 1% of the storage

wall area.

• The trombe wall should be adequately shaded for reducingsummer gains.




In this technique, incident solarradiation is trapped by the roof and isused for heating interior spaces.

In the Northern Hemisphere, the systemusually consists of an inclined south-facing glazing and a north-slopinginsulated surface on the roof. Betweenthe roof and the insulation, an air pocketis formed, which is heated by solar

radiation.

A moveable insulation can be used toreduce heat loss through glazed panesduring nights.

There can be variations in the detailingof the roof air heating systems.

In the Himachal Pradesh StateCooperative Bank building, the southglazing is in the form of solar collectors warming the air and a blower fancirculating the air to the interior spaces.


Roof base air heating system for winter heating in HimachalPradesh State Cooperative Building.



Water walls are based on the same principle as that for trombe walls, except

that they employ water as the thermal storage material.

A water wall is a thermal storage wall made up of drums of water stacked up behindglazing. It is usually painted black to increase heat absorption.

It is more effective in reducing temperature swings, but the time lag is less.

Heat transfer through water walls is much faster than that for trombe

walls.

Therefore, distribution of heat needs to be controlled

if it is not immediately required for heating the building.

Buildings that work during the daytime, such as schools

and offices, benefit from the rapid heat transfer in the

water wall.

Overheating during summer may be prevented by

using suitable shading devices.




A sun space or solarium is the combination of direct and indirect gain systems.

The solar radiation heats up the sun

space directly, which in turn heatsup the living space (separated from the

sun space by a mass wall) by convection

and conduction through the mass wall.

In the northern hemisphere, the

basic requirements of buildings heated by

sun space are

(a)a glazed south facing collector space

attached yet separated from the building

(b) Living space separated from the sun space

by a thermal storage wall. Sunspaces may be used as winter gardens adjacent to the living space.

The Himurja building in Shimla has well designed solarium as integral part of south wall to maximisesolar gain.




CASE STUDY




General Information:

Client: Himachal Pradesh StateGovernment Secretariat

City: Shimla

Climate: Cold

Operational schedule – 7 hours,6 working days in a week




Longer Facades: NE-SW

NE façade gets a certain amount of daylight and solar heat due early in

the mornings. SW facade has more optimum

amount of daylight and solar heatin winter months.


Walls

Walls of air-conditioned zones in all

blocks – 230mm brick with 12.5mm

plaster .

Roof

150mm concrete slab with

cement tile.



6 mm clear single glazed windows.

Clear glass helps in receivingrequired amount of solar heatgain in early mornings and wintermonths which is required in coldclimate of Shimla.




Lighting system accounts for 29.7%(indoor: 95kW).

Luminaries used: mostly open typeluminaries in office spaces, CFLs withelectronic ballasts in corridors and

florescent lamps in storages, electricaland mechanical rooms.

The electronic ballasts saves approx 20-30% in energy consumption over the

standard ballasts.

Good natural light available in officespaces.




Central heating plant withcapacity of 1470kW.

Block1: 630kW, Block2:840kW

COP: 1 (rated)




Lighting Energy Performanceof the Building


• Annual Consumption (lighting) – 356044KWh•Lighting Performance Index – 28KWh/Sqmt/annum

Space Conditioning Energy Performance of the Building

• Annual Consumption (A/C) – 518208KWh•HVAC Performance Index – 41KWh/Sqmt/annum



ParametersSolar passive Case (Existing

Building) features

Conventional Case

(Building features)

Building orientationBuilding longer facades are facing SW-NE Building Longer East-west orientation

No roof and wall shading No roof and wall shading

Building Envelope

No insulation on wall and roof.

U value for Wall -1.92 W/m2/K

U Value for Roof-2.74W/m2/K

No insulation on wall and roof.

U value for Wall -2.7 W/m2/K

U Value for Roof-2.68 W/m2/K

Single Glazed windows (U value of glass - 5.8

W/m2/K and Shading coefficient - 0.87)

WWR – 50%

Single Glazed windows (U value of glass -

4.3 W/m2/K and Shading coefficient -

0.89)

WWR – 28%

Energy performance

Index (KWh/m2/yr) 70 237





MONTH JANUARY FEBRUARY MARCH APRIL MAY

LITERATURE STUDY

SURVEY ANDDOCUMENTATION

ANALYSIS OF DATA

CONCLUSION/SUMMARY



While achieving extra value from sustainable attributesmay involve more innovative approaches to assetmanagement, the use of advanced sustainableapproaches is not necessarily complex. As

governments move to increase price messaging (taxesand credits) to encourage sustainability, this willincreasingly affect net value of existing assets andimprove investment performance for buildingsadapted or adaptable to these goals. It will also

increasingly encourage owners to consider lesstraditional solutions to enhancing asset performanceand value.




Uses of landscaping for energy conservation

Giani, Florida: Department of Physical Sciences, Florida InternationalUniversity

Manual on solar passive architecture: energy systems engineering IIT Delhi and

Solar Energy Centre, Ministry of Non-conventional Energy Sources,

Government of India, New Delhi)

Bansal N K, Hauser G, Minke G. Passive building design: A handbook of Natural climatic control.

Nayak J K, Hazra R. Development of design guidelines by laws.




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High Performance Buildings in Cold Climates