ENERGY PRODUCIN

G BUILDINGS

Submitted By- Rohit AroraM.Tech Structural Engineering

NIT PatnaRoll No-1523019

SeminarOn:

INTRODUCTIONIn today's energy hungry world where the

concepts of zero energy buildings and green buildings are coming up which reduces the energy consumption to bare minimum, a new concept of energy producing building can be introduced. Energy producing buildings not only consume less energy but also they produces energy on their own.In this lecture,

Buildings integrated with wind turbines Glass panels with photovoltaic cellsWill be discussed.

BUILDINGS INTEGRATED WITH WIND TURBINES

Bahrain World Trade Centre, Bahrain City.

Apartment Building- “Strata-E1” or “Razor” at Elephant and Castle, Southwark, London with 3 turbines integrated up at top.

INTRODUCTION At the present time the debates and discussion are being held about viability of wind. Wind turbines are cost effective and efficient if they are placed on high poles, or integrated with a facility in combination with any renewable energy source. Wind speed increases with height so engineers came to the idea of installing wind turbines on top of buildings.

Rooftop wind farm at Oklahoma Medical Research Foundation, Oklahoma City, Ohio, USA.

WIND TURBINE IN URBAN ENVIRONMENT

Wind follows the path of minimum resistance by going around obstacles such as hills, mountain passes and buildings. If a wind turbine is capable to use this increase in speed and density its energy production can be up to two times higher than when standing in an undistrubed flow.

However, placed on the leeward side of a large obstacle, the output will be reduced to half of the yield normally expected. Since wind turbines designed for urban areas are small, averaging does not diminish the phenomena that describes the power yield.

REQUIREMENTS OF WIND TURBINE IN URBAN ENVIRONMENT

High conversion efficiency and low initial cost.

Good performance in complex winds. Safe operation in the urban

environment. Low noise level. Simple, rugged design. Minimised maintenance. Aesthetic appearance.

LOCATION OF WIND TURBINE

Locating between diffuser shaped buildings

In this case buildings are positioned in such a way that they act as a diffuser for the wind turbine. Many tests were carried out on horizontal axes wind turbines in ring shaped diffusers. This combination results in a high aerodynamic efficiency compared to other possibilities. The diffuser needs to be long in order to generate an appreciable gain in aerodynamic efficiency. The common shape of the diffuser augmented wind turbine is not very suitable for the built environment. Because of that a combination of “diffuser” and “ duct” is often applied.

Fig- The two towers of Bahrain World Trade Centre are not in same vertical plane. The inclination generates diffusion effect thus concentrating wind force towards the central wind turbines. This increases the efficiency of building integrated wind turbines.

Fig-Wind Simulation on Bahrain World Trade Centre. The red part shows high wind intensity and the blue colour shows low wind intensity areas

Pearl River Tower is a 71-story, 309.6 m, clean technology neofuturistic skyscraper at the junction of Jinsui Road/Zhujiang Avenue West, Tianhe District, Guangzhou, China.

Locating wind turbines in building facades (Along edges of

building)

Several designers have created building integrated wind turbines that fuses magnificent sculpture-like facades to augment wind flows onto turbines and generate more energy than is traditionally possible. Simultaneously, these artistic wind generating facades overcome some of the traditional problems with this type of dynamic facade, like noise and vibration.

Many of these building integrated wind energy systems use the concept of Wind Assisted Rotor Platform (WARP). These consist of small wind turbines mounted to the exterior of an aerodynamically shaped building. The saddle ridge shaped modules swirl around the building to channel and amplify the flows of wind

Fig- Wind turbines integrated along the edges into a Chicago parking.

Kinetica Apartments, Dalston building, London

Locating on the building rooftop

For locating on the roof it has to be kept in mind that the flow separates at the leading roof edge and has an angle of about 30-40 degrees to the horizontal roof. For a Darrieus turbine this effect will be less important. For common tip speeds the blades will experience an almost horizontal flow. On a HAWT the tilt will have a larger influence. The airfoils will stall, the aerodynamic efficiency will decrease and the rotor load will be non-uniform. So the Darrieus turbine seems preferable for locating on the roof of buildings.

Fig- Darrieus Turbine

Fig- Strata E1 “Razor”

PROBLEMS WITH SUCH BUILDINGS The first building integrated with wind turbine-

Bahrain WTC has low efficiency and a large payback time. It fulfils around 15% of the electricity needs.

noise that turbines make[2].The wind flow creates noise that can be uncomfortable no matter of the frequency.

The structures with integrated wind turbines are unoccupied around the floors where they are placed.

Rotation of turbine generates a centrifugal thrust on the building.

Vibrations causes dynamic loadings on the structure.

High initial cost. Tricky designing of structures. Hazards due to heavy rotating machinery.

ADVANTAGES Makes buildings self sufficient. Reduces dependence on fossil fuels. Reduces the carbon emission content of the

buildings. Uses renewable source of energy. Long term savings. A wind turbine between two towers such as

in Bahrain WTC is 25% more efficient than free standing wind turbine.

Acts as a landmark, tourists visits such buildings, and gets educated and knowledge about the need of such structures.

UPCOMING/PROPOSED STRUCTURES

“COR” Building, Miami, USA

Fig- Freedom Tower, New York

Fig- Proposed Wind Turbines under a road bridge between Italy and Scilla.

GLASS WITH PV CELLS

Window/Facade glasses with PV cells is not a new phenomena. But, earlier these glasses came in different colors, gave uneasy feeling to the residents.

Now transparent glass panels with photovoltaic cells have been developed.

Thus such glass panels can replace our orthodox glass panels with no transparency what-so-ever and these produces electricity too.

Such glass is not completely transparent.

Pearl Tower- China. World’s First Zero energy Building, most energy efficient building of the world, incorporates glass panels with PV cells.

WORKING OF PV CELLS

Compared to how solar energy has functioned through PV cells, the method used by the transparent solar cell is somewhat counterintuitive. In the most basic terms, solar PV cells capture the photons and convert those pockets of light into electricity. By contrast, a transparent cell would allow the light to pass directly through, without capturing the photons.

Fig- Glass panels with PV cells. Reduced transparency.

Glass with PV cells at Pfizer company’s building at Granada, Spain

ADVANTAGES Produces electricity with the help of sunlight.

Reduces dependence on fossil fuels. Solar cell farms requires large cover land. So,

glass with PV cells can save such use of land. Low maintenance. Transparent glass with PV cells absorbs only

the harmful UV and infrared rays of sun and allows visible light to pass through.

It reflects most of the heat. Therefore, in summers inside temp of building doesn’t escalates high. Thus, reducing the cooling energy required, and vice versa in summers.

CONCLUSIONThe renewable sources of energy can be accommodated on the structures to reduce the dependence of structures on fossil fuels.The lesser use of fossil fuels means lesser carbon footprint of the building. To harness wind energy and solar energy large farms have to be set up.Such farms requires large surface area to be set up.So, even though a little high initial investment is required to set up such turbines and glass with PV cells, it reduces the overall energy cost over a long period of time and also results to a greener planet.

REFERENCES[1] http://www.treehugger.com/renewable-energy/worlds-first-building-integrated-wind-turbines.html

[2] http://www.treehugger.com/renewable-energy/does-building-integrated-wind-power-work.html

[3]http://www.awea.org/learnabout/publications/upload/awea_and_canwea_sound_white_paper.pdf

[4] http://www.som.com/content.cfm/www_projects?sort_by=FW

[5] http://en.wikipedia.org/wiki/Strata_SE1

[6]http://www.buildinggreen.com/auth/article.cfm/2009/4/29/The-Folly-of-Building-Integrated-Wind

[7] http://www.solaripedia.com/13/93/folly_of_building-integrated_wind.html

[8]Mladen Bošnjaković, senior lecturer, MSc, renewable energy, programming of CNC machines

[9] http://planetsave.com/2015/09/05/solar-power-windows-ready-for-production.html

[10] http://www.extremetech.com/extreme/188667-a-fully-transparent-solar-cell-that-could-make-every-window-and-screen-a-power-source.html

[11] http://inhabitat.com/revolutionary-transparent-solar-cells-could-produce-50-times-more-energy-than-conventional-solar.html

THANK YOU