Retrofitting of vikas minar facade design final

RETROFITTING VIKAS MINARFAÇADE TREATMENT“WAYS TO REDUCE ENERGY CONSUMTION OF A BUILDING THROUGH FAÇADE TREATMENT”

DEEPAK BOHRAGYANENDITA SHAILYSANKET VATSSUDEEP V. ZUMBRE

FAÇADE• OPENINGS• WALL

OPENINGONE OF THE MAIN FUNCTION OF OPENINGS IS NATURAL DAYLIGHTING.NATURAL DAYLIGHTING, ENERGY SAVING IN THE RANGE OF 60 % IN TERMS OF LIGHTING LOAD CAN BE ACHIVED THROUGH GOOD DESIGN

NATURAL DAYLIGHTING1. Allow NO direct sunlight penetration,

except in circulation spaces.WHY DIRECT SUNLIGHT IS NOT GOOD?• Too bright, causing contrast and visual comfort

problems.• Significant infrared radiation causes local thermal

discomfort.• Does not diffuse the light, making use of electric

lighting necessary and increasing the cooling load.

DEVICES FOR SHADING CONTROL• Movable opaque• Louvers• Fixed overhangs

2. Shades: design to prevent glare and reflect daylight deeper into building space.

3. Glazing: select for high visual light transmittance without increasing heat gain.Visible Light TransmittanceThe percentage of visible light (380 - 780 nm) that is transmitted through the glass.

Solar Heat Gain Coefficient (SHGC)The portion of directly transmitted and absorbed solar energy that enters into the building's interior. The higher the SHGC, the higher the heat gain.U VALUEA measure of heat gain or heat loss through glass due to the differences between indoor and outdoor temperatures.

Single Glazed Unit (6mm thick, coating face 2)

Light Factors

Solar Radiation

Ashrae Values

Colour Shade

Code Transmission

Reflection Transmission

Reflectance

Absorbtion

U value U ValueSummer

U Value Winter

RelativeHeat Gain

Ext. Int. W/sqmK W/sqmK W/sqmK W/Sqm Moonshine

KT 155 46 17 10 25 18 57 1.7 1.69 1.88 256

Icy Menthol

KT 140 36 23 12 18 22 64 1.7 1.66 1.84 203

Misty BlueKT 755 30 10 10 15 9 82 1.7 1.69 1.89 183 Twilight Blue

KT740 24 12 11 11 10 89 1.7 1.66 1.86 153

Olive KT 455 39 13 10 18 10 77 1.7 1.69 1.89 205 Tropca Green KT 440 31 18 12 14 12 84 1.7 1.66 1.85 169

Source: http://in.saint-gobain-glass.com/b2c/default.asp?nav1=pr&nav2=single%20pane&id=22628

4. Integrated electric lighting: ensure appropriate dimming controls; account for electric and cooling load reductions.

5. Interior materials: select finishes and colours to maximize surface reflectance.

WALLIn a composite climatic condition where temperature gets very high in summer and very low in winters wall play significant role in energy consumption of the building due to heat gain in summer and heat loss in winter through it.WAYS TO REDUCE HEAT GAIN THROUGH WALL• USING THERMAL INSULATING MATERIALS.• USING TECHNIQUES WHICH INCREASES

INSULATING CAPACITY OF WALL (FOR EXAMPLE; RAT TRAP BOND)

• LIGHT COLOUR FINSHING TO MINIMIZE SOLAR HEAT ABSORPTION.

Building Integrated Photovoltaics (BIPV)

A Building Integrated Photovoltaics (BIPV) system consists of integrating photovoltaics modules into the building envelope, such as the roof or the façade. By simultaneously serving as building envelope material and power generator, BIPV systems can provide savings in materials and electricity costs, reduce use of fossil fuels and emission of ozone depleting gases, and add architectural interest to the building.

A PV skylight entryway (Courtesy of DOE/NREL)Advantages : • While the majority of BIPV systems

are interfaced with the available utility grid, BIPV may also be used in stand-alone, off-grid systems.

• One of the benefits of grid-tied BIPV systems is that, with a cooperative utility policy, the storage system is essentially free.

• It is also 100% efficient and unlimited in capacity.

• Both the building owner and the utility benefit with grid-tied BIPV.

• The on-site production of solar electricity is typically greatest at or near the time of a building's and the utility's peak loads.

http://www.wbdg.org/resources/bipv.php

http://www.nrel.gov/

Photovoltaics (PV) Technologies• Crystalline Silicon ModulesCrystalline-type modules are generally the most common, most efficient, and the most expensive of the commercially available technologies. Although photovoltaic modules degrade over time, crystalline-type modules are typically guaranteed through warranties to produce at least 80% of their original power after 20 to 25 years. Crystalline-type modules have a lifespan in the 25 to 30 year range but can keep producing energy beyond this range. Typical overall efficiency of crystalline solar panels is between 12% and 15% (the percentage of the solar energy they convert to electricity).Typical installed cost of a federal roof-mounted system is Rs. 350 to Rs. 440 per watt .• Thin-Film ModulesSecond-generation solar cells are known as thin-film solar cells. They are flexible and frequently used in building-integrated photovoltaic (BIPV) applications such as roof shingles, tiles, building facades, or the glazing for skylights. These new materials allow for cheaper resources and production, so the cost of the system—as a function of its output—is reduced. The efficiency of thin-film solar cells is generally lower than crystalline cells—typically in the range of 6% to 8%. As such, thin-film technologies require more space to produce the same amount of electricity as a crystalline-type module. Where space is not an issue, these types of modules can be a more cost-effective option. Typical installed cost of a large-scale ground-mounted system is Rs. 165 to Rs. 220 per watt.

Team Germany's surPLUShome is covered with thin-film copper indium diselenide photovoltaic panels on all sides

Installation of crystalline-type modules


Concentrating Photovoltaic ModulesConcentrating photovoltaic modules use plastic lenses or mirrors to concentrate sunlight onto a very small piece of high-efficiency photovoltaic material. As a result, very little of the costly photovoltaic cells are used and can reach cell efficiency much higher than flat-plate systems. Concentrating photovoltaic systems are becoming a more cost-effective option for utilities and industry. Furthermore, system efficiency can be as high as 30%.

Emerging TechnologiesThird-generation solar cells are being made from a variety of new materials besides silicon, including solar inks, conventional printing press technologies, solar dyes, and conductive plastics. These options are technically attractive because they are made of low-cost materials. Manufacturing could also be significantly less expensive than older solid-state cell designs. However, the efficiency of these technologies is expected to be a lot lower than the typical thin film.


APPLICATIONS• Photovoltaics may be integrated into many different assemblies within a building

envelope:• Solar cells can be incorporated into the façade of a building, complementing or

replacing traditional view or spandrel glass. Often, these installations are vertical, reducing access to available solar resources, but the large surface area of buildings can help compensate for the reduced power.

• Photovoltaics may be incorporated into awnings and saw-tooth designs on a building façade. These increase access to direct sunlight while providing additional architectural benefits such as passive shading.

• The use of PV in roofing systems can provide a direct replacement for batten and seam metal roofing and traditional 3-tab asphalt shingles.

• Using PV for skylight systems can be both an economical use of PV and an exciting design feature.

Left to right: APS Factory in Fairfield, CA and Intercultural Center, Georgetown University in Washington, DC

Design Considerations:

The sun-path in the northern hemisphere moves through the South sky.Hence ideal orientation for fixing of SPV modules is on South façade, horizontal elements (atriums, skylights etc) or ideally fixed with tilt facing the south sky.

http://www.konarksolar.com/tata/TBP-BIPV.pdf]

Forms of integration in buildingsThere are many alternatives for integrating photovoltaic into buildings. Generally there are three areas of the building where photovoltaic-modules can easily be integrated:• The roof • The façade • The sun screening components

http://pvcert.gr/assets/media/PDF/Publications/Other%20Publications/39.BIPV%20BEST%20PRACTICES.pdf

There are three different alternatives for installing solar-modules on a roof.

I. The most common way is not to integrate them into the building but to add them to the surface of the roof.


II. Another possibility is to integrate them directly into the roof.

III. The third and most fully integrated solution involves making the PV-modules act as the roof itself.


Fixing of Standard Solar Modules on Building Roofs or Open Ground:

Standard Solar PV Modules are available in two sizes:80Wp ~ 1.2 m x 0.55 m and 160Wp ~ 1.6m x 0.8m• They are mounted on a ‘module mounting structure’ (as shown above) with a tilt equal

to the latitude of the site.• These modules can be placed in any location that is shadow free such building roof top,

car-parks, integrated into landscape design or boundary walls.• Consultants/architects can find the total no. of modules that can fit onto the available

roof area as shown below.• Total solar power plant capacity in kW = no. of modules X 80 or 160 (as per module of

choice) http://www.konarksolar.com/tata/TBP-BIPV.pdf]

Spacing between modules can be reduced from given lengths.

Layout for 160Wp Solar Module Layout for 80Wp Solar Module

http://www.konarksolar.com/tata/TBP-BIPV.pdf]

The Façade

Like roofs, there three options for integrating solar modules into façades:

Modern façades have different functions, for example:• Heat protection• Insulation glass• Sun protection• Noise protectionUsing a solar glass-glass module you can achieve all of these features with the added advantage of• Environmental friendly energy production!

The solar cells can be integrated in a cold façade like a curtain wall façade or in warm façades.

Example for a warm façade. Example for a cold façade


The power connectionThe picture below shows an example of two modules can be connected. The glass-glass modules have a very easy-to-handle electricity connecting system. With these types of electrical connection it is possible to hide the cables inside the substructure to achieve a uniform, aesthetically appealing result with no distracting cableways.


Examples of façade constructions

The modules can be integrated directly into the construction of the façade. Because they are made of glass, they can be handled like a normal glass pane.

Solar modules integrated in the construction

There are different ways of integrating modules into the construction. For example

you can use a façade with an ordinary construction.

Photovoltaic modules integrated in an ordinaryconstruction


Estimated efficiencies of PV module

Parameters 200 Wp c-Si 230 Wp c-Si 340 Wp thin film

380 Wp thin film

Type of Module Crystalline Silicon Thin Film

Power Rating 200 230 340 380

Area (m2) 1.646 5.72

Wp/m2 121.51 139.73 59.44 66.43

Efficiency 12.15% 13.97% 5.94% 6.64%

It is evident from the data in the above table that for the given area, the module with the higher peak power rating is more efficient. On the other hand, if the 200 Wp module is 13.97% efficient, it will have an area of 1.43 m2 (lesser than 1.646 m2 mentioned in the table). This explains inverse relationship of the area with the efficiency .i.e. more efficient the module, lesser is the area required to accomplish given peak rating.

Parameters c-Si Low c-Si High Thin Low

Thin High

Efficiency 12.15% 13.97% 5.94% 6.64%

Average Daily Solar Radiation (kWh/m2-day) 5.5 ( or 5.5 hours of 1000 W/m2)

Electricity generated (kWh/m2-day) 0.6683 0.7684 0.3267 0.3652

Estimated electricity generation on per unit area basis from PV modules of different efficiencies.

http://www.ncpre.iitb.ac.in/page.php?pageid=51

Country/Tariff Roof-Top Ground-Based BIPV TermIndia Rs. 21.05/kWh Rs. 21.05/kWh Rs. 21.05/kWh 20 years

By Nilima Choudhury - 11 January 2012, 13:27 http://www.pv-tech.org/tariff_watch/india

http://www.ncpre.iitb.ac.in/page.php?pageid=51

mailto:[email protected]



Shading of RoofShading of roof through design features like pergolas or solar photovoltaic panels helps in reducing the incident direct solar radiation on the roof surface. This in turn helps to reduce the air temperature of the roof and conduction gains in the space below. For ex: The figure on the right side shows the fully shaded roof of Centre for Environment, IIT Kanpur through Pergolas and Solar PV panels.Impact of shaded roof It is observed in air conditioned buildings, adopting ECBC envelope in building has high energy saving potential. However, shaded roof has similar energy saving potential as that of ECBC compliant roof. Shading of roof could can be done by designing pergolas, trellis on roof or by installation of solar panels. Fully shaded roof of Research lab in IIT, Kanpur through pergolas

& Solar PV panels

Cool Roof: Along with shading of roof, solar passive design also recommends cool roof. Cool roofs are roofs covered with a reflective coating that has high emissivity property which is very effective in reflecting the sun‘s energy away from the roof surface. This quality greatly helps in reducing the cooling load that needs to be met by the HVAC system. Combination of insulated roof with cool roof has high saving energy potential.

http://high-performancebuildings.org/pdf/ECM1/ECM1_Technical_information_Composite.pdf

Impact of Orientation and Shaded Envelope Impact of passive design strategies/ low energy design strategies have been studied in this climate for the combined impact of orientation and shaded envelope. It is observed that with N-W orientation (longer facades) and shaded envelope results in 19.2% reduction in the EPI. The following graph shows the impact of these strategies on the building coil load and electrical load in composite climate.

External shading for windows as an effective means of shading Horizontal fins as an external shading device

http://high-performancebuildings.org/pdf/ECM1/ECM1_Technical_information_Composite.pdf

Horizontal & vertical fins as an external shading device

Adjustable and Movable types of louvers (www. fsec.ucf.edu)

Fixed types of louvers (www.wbdg.org)

GREEN WALLOther than producing oxygen, vertical greenery has

the benefit of reducing heat transmittance and lessening the effect of Urban Heat Islands . Green walls, or vertical gardens as they are commonly known, are an important application of the green roof benefits to building walls. A green wall is a wall, either free-standing or part of a building, that is partially or completely covered with vegetation and, in some cases, soil or an inorganic growing medium.

Advantages of green façade systems are:• Bigger spaces can be cover with little maintenance.

• Improvement of the microclimate (reducing temperature, maintain air humidity).

• Prevention of overheating, They help reduce the room temperature , thus saving on electricity.

• Plants also reduce the amount of electrostatic pollution released by computers and other appliances.

• Dust filtration

• They help in Water conservation.

• Water can be reused.

• They act as sound buffers.

• Long life.Source-http://builditbackgreen.org/bushfires/interactive-green-building-guide.aspx

STRUCTURAL DETAIL-

Reduced Energy 0.029 kWh/ft2

AC efficiency 500W/1000W

Electricity Rates 7 Rs/ kWh

Total Savings = 10 Rs/ ft2day

They can reduce the surface temperature of walls by as much as 10 ⁰C which results in significant air-conditioning savings.

ENERGY SAVING

Total Area = 1087 ft2

Total Saving = 1087x10x30 = 326087 Rs/month

Source-http://hortibiotech.com/wpcontent/uploads/2012/03/Vertical_green_wall

THE DOUBLE SKIN FACADE

An insulated wall and a second shading or sheltering layer, are used so that the inner wall is shielded from weather.

• The windows in the inner wall are operable and sometimes computer controlled to maximize natural ventilation.

• A variety of technologies are being used for the outer façade including louvers, woven mesh, perforated screens and green (plant) screens. They may actively change with varying conditions or remain passively fixed.

• The outer façade can transform the appearance of lower cost new buildings or revitalize outdated existing facades at a much more reasonable cost than a more elaborate curtain wall. This makes them a cost effective aesthetic choice for renovation or new construction.

Development of a Double-Skin Façade for SustainableRenovation of Old Buildings- 7th International Symposium on Sustainable Healthy Buildings, Seoul, Korea (18 May 2012)

The intermediate cavity space can be natural solar collectors and a buffer to prevent overheating with properly-operated ventilation.

The results indicate that a double skin facade system with single clear glazing as the inner pane and double reflective glazing as the outer pane can provide an annual saving of around 26% in building cooling energy, as compared to a conventional single skin facade with single absorptive glazing.

Active Second Façade Systems

• These systems employ an operable shading system over the insulated glass façade, which maybe between inner and outer glass layers or be the outermost wall.

• The two layers can be from 0.2 to 2 m (0.7 to 6.6 ft) apart, and incorporate integrated sunshades and natural ventilation.

• All that have computer-controlled mechanical operating systems that work with the building’s heating and cooling systems, making it possible for them to respond dynamically to varying conditions.

• By adjusting to match the sun’s trajectory, they maximize the benefits of solar radiation while minimizing heat gain.

• Energy is necessary to operate these assemblies, and maintenance of the mechanical and sensing systems is required so they are not suitable for all applications.

These active motorized sunshade systems have moveable triangular, square and trapezoidal fins are automatically adjusted with changing conditions to save energy. Used in combination with natural ventilation, the system eliminated the need for air conditioning.ThyssenKrupp AG headquartersPhotos: Courtesy of ThyssenKrupp AG

Transformative Passive Systems• Unlike tensile supported systems that parallel the insulated wall,

lightweight framing supports for woven mesh or perforated panels allow the distance between the inner insulated skin and exterior hybrid second skin to vary making seamless curving, geometric and other shapes possible.

• This can dramatically change the appearance of a new or existing building at a much lower cost than installing an undulating insulated curtain wall.

• Passive screens avoid the maintenance requirements of automated systems and are suitable for any environment.The curves on the exterior were

created by a stainless steel mesh metal panel system.

• The design eliminated the need for air-conditioning in common spaces which substantially reduced energy requirements.

• The woven mesh maximizes natural light inside the building, while creating a distinctive identity and enhancing energy savings and sustainability.

Guangzhou, China’s second Children’s Activity CenterPhoto: Steffian Bradley Architects

The case with a 60cm-wide cavity offers a cut down of annual cooling energy of 37%.

For 90cm-wide cavity, its annual cooling energy is 40% less than the original case.The percentage of cooling energy saving from double-skin facade case with a 120cm-wide cavity (21%) is not significantly higher than the case with 90cm-wide (40%), even though the cavity becomes much wider.

With appropriate design with 90cm-wide cavity, a total energy of 38% can be saved in annual heating, as compared to a base case building.

ANALYSIS

INTERMEDIATE CAVITY WIDTH OPTIONSTotal Energy Saving is 91200 kWh per Year.

ANNUAL COOLING AND HEATING LOAD BY CHANGING CAVITY DIMENSION

Cut down in annual cooling energy, ranging from 3% (30cm) to 40% (90cm).

Heating energy saving range from 2% (30cm) up to 43% (120cm).

A simulation design study for the façade renovation Of an office building- Canadian Solar Buildings Conference Montreal, August 20-24, 2004 Refereed Paper

• During heating season, the shading system should horizontal: A large amount of solar radiation can pass through the facade because the low altitude of the sun above the horizon allows a direct gain, together with an indirect contribution linked to multiple reflections of the slat surface constituting the shading system.

• In cooling season, to avoid overheating and discomfort, the shading device should be adjusted with a high tilt angle, stopping the solar radiation.

SHADING IN THE DSF

• Cut down in annual cooling energy, ranges from 46% (10cm) to 47% (30cm). Heating energy saving was found ranging from 23% (10cm) up to 26% (30cm).

• Comparing the 90cm-wide double-skin case without shading device, annual saving in cooling energy of 10%, 11% and 13% were resulted from the cases of 10cm-wide, 20cm-wide and 30cm-wide louver, respectively.


Total Energy Saving is 1,04,700 kWh per Year.

SHAPE OF DOUBLE SKIN CAVITY

A functional shape to activate more amount of natural ventilation is the effective option in managing the interaction between the outdoors and the internal spaces.A traditional shape of DSF has a water leak problem when it rains. As a solution, a rectangular shaped cavity is suggested which is called scooped.

PILOTED CLOSED SCOOPED SHADED OPENED

http://www.imoa.info/moly_uses/moly_grade_stainless_steels/architecture/bioclimatic_facades.php

• The heating energy demand is about 7% lower for the single-skin facade with the closed alternative configuration of DSF solution compared to the traditional double-skin facade.

• For the case with the scoop, up to 3% saving in cooling energy can be achieved.

• Saving percentages from 1% in cooling up to 4% in heating are obtained from this scoop case.


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