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Institute of Technology & Management, Maharajganj

Presented by: Saroj Khadka

4th year, Civil Engg.

1047200059

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Contents

Net Zero Energy Buildings

Classify ZEBs by RenewableEnergy supply

Zero Energy Buildings inWorld

Design strategies for low andnet zero energy buildings

Sustainable system included inbuilding

Solar array system on roofs

Advantages of Zero energybuildings

Disadvantages of Zero energybuildings 3

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Net Zero Energy buildings(NzEb)

Net Zero Energy buildings means the buildings generate as much energy and power as it consumes on annual basis.

NZEB is a grid-connected and energy-efficient building that balances its totalannual energy needs by on-sitegeneration.

Main concept of ZEB, 100 % ofenergy it requires come from lowcost, locally available, non polluting,renewable energy sources, even ofenergy is generated off the site.

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Four well-documented definitions:

Net Zero Site Energy (site ZEB) :

Amount of energy provided by on-site renewable energy sources isequal to the amount of energy used by the building.

Net off-site zero energy (off-site ZEB):

Similar to previous one, but consider purchasing of energy off-site from100% renewable energy sources

Net zero energy costs (cost ZEB):

The cost of purchasing energy is balanced by income from sales ofelectricity to the grid of electricity generated on-site.

Net zero energy emissions:

Zero carbon building or zero emission building

The carbon emissions generated from the on-site or off-site fossil fueluse are balanced by the amount of on-site renewable energyproduction.

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Classifying ZEBs by Renewable Energy Supply

ZEB Classification

ZEB Supply-Side Options

A Use renewable energy sources available within the building’s footprint and dedicated to the building(Examples: Photovoltaic, solar hot water and wind located on the building.)

B Use renewable energy sources as described in ZEB:A And/or Use renewable energy sources available at the building site and dedicated to the building (Examples: Photovoltaic, solar hot water, low-impact hydroelectric, and wind located on parking lots, adjacent open space, but not physically mounted on the building.)

C Use renewable energy sources as described in ZEB:A; and/or ZEB:B And Use renewable energy sources available off site to generate energy on site and dedicated to the building (Examples: Biomass, wood pellets, ethanol, or biodiesel that can be imported from off site, or collected from waste streams from on-site processes that can be used on site to generate electricity and heat.)

D Use renewable energy sources as described in ZEB:A, ZEB:B, and /or ZEB:C And Purchase recently added off-site renewable energy sources, as certified from Green-E (2009) or other equivalent renewable energy certification programs. Continue to purchase the generation from this new resource to maintain ZEB status. (Examples: Utility-based wind, photovoltaic, emissions credits, or other “green” purchasing options. All off-site purchases must be certified as recently added renewable energy )

On-Site Supply Options

Off-Site Supply Options

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Zero energy buildings

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Design strategies of low & net zero energy buildings

1) Building System Performance Design Good design practices reduce overall electrical energy demands

THERMOMASS Insulation Building System/TEX-COTE cool wall Highly insulated roof system Day lighting, fenestration minimized on south wall/max on north

wall

centralized mechanical/electrical rooms Energy efficient insulated window system HVAC and electrical system

2) Systems incorporated into the design as bid options. Solar Photovoltaic Wind Turbine

Rainwater harvesting

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Other Sustainable Systems Included in the

Building

Sustainable Systems Mechanical/plumbing

Split DX HVAC with energy recovery technology

HVAC system

Rainwater harvesting, recovery and recycling, reuse in toilets and urinals

Water conserving fixtures, low flow, dual flush

Electrical

Day lighting controls and occupancy sensors

Nighttime illumination with fluorescent & LED lighting

Building is +42% more efficient than traditional buildings

Photovoltaic System 10

Solar Array Installed on Roofs

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Solar Array System PV Crystalline Panel System

PV Crystalline modules, utilizingthe most efficient panel at thetime of construction

2.5’x5’ panel at 235 watts perpanel, 78,960 watts of power

336 panels located on buildingroofs

Life expectancy of panels is 25years on power output at 80%

Expected payback period is 7 years

Photovoltaic System located onthe roof act as an umbrella

Panels protect the roof fromenvironmental damage

Panels keep the roof cooler aidingin smaller cooling demands

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Grid connectedwind energysystems

Grid connectedPV systems

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Zero Energy Office (ZEO) Building in Malaysia

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Zero energy office building in Guangdong, China

(Pearl River Tower, for Guangdong Tobacco

Company)

(completed in 2009)

Main features:- Orientation of the building- Low-E-glass- Double-layer curtain-wall- Chilled slab concrete ceilings- Lighting efficiency- Geothermal heat sink- Energy storage- Wind-Integrated photovoltaics- Microturbines

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Singapore zero energy building –Building and

Construction Authority (BCA) Academy

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Energy design features:- Triple glazed- High thermal insulation- 777 m² of solar panels- Co-generation- District heating & electricity

Beddington Zero Energy Development (BedZED), UK

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Self-sufficient solar house in Freiburg, Germany

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Zero Energy Buildings

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The 1,700-sf Science House (at center in photo) features an 8.8 kW photovoltaic array and ground-source heat pumps. 20

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1) Low ventilation intake

2) High ventilation exhaust

3 ) Spectrally selective glazing

in thermally broken frame

4) Day lighting in internal

hallway

5) Operable skylight

6) Peel-n-stick photo voltaic

7) 30 kW transformer

connected to electrical grid

8) Radiant slab heating

toilets

pump

cistern

transformer

grid

Chartwell School NZEB Strategies

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Section of a new office building, now under construction, for the David and Lucile Packard Foundation, Los Altos, Calif. The49,000-sf facility, which will house 120 employees, will use chilled beams, a high-performance envelope, plug load reductions,and a 285 kW photovoltaic system to achieve net-zero energy status and LEED Platinum certification.

1) PV panels supply 100% of renewable energy2) Solar hot water panels3) 40-foot width maximizes day lightingand natural ventilation4) Dynamic exterior blinds lower with direct sun5) Layered shading strategies6) Triple-glazed, highly insulating windows7) Chilled beams with 100% fresh airCourtyard

Alley

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Advantages:

Increased comfort due to more uniform interior temperatures.

Improved reliability- Photovoltaic systems have 25 yrs warranties, seldom failed during weather problems

e.g:Photovoltaic system on the Walt Disney World EPCOT Energy Pavilion are still working fine till today after going through 3 recent hurricanes.

Reduce carbon emissions

Reduce dependence on fossil fuels

Reduce energy consumption and costs

Value of ZEB Building relative to similar conventional building should increase every time energy costs increase.

Free from carbon emission taxes/ penalties and other future legislative restrictions.

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Disadvantages:

High initial cost.

Few designers or builders have necessary skills or experience to build ZEBS.

Value of Photovoltaic solar cells equipment technology price has been falling at roughly 17% per year- it may lessen the value of capital invested in solar electric system.

Solar energy capture using house envelope only works in locations unobstructed from south.

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Conclusion

NZEBs are vital to the nation’s energy-efficient future.

To design and build an NZEB, energy efficiency and renewable energy generation must be requirements from the beginning.

A cost-effective NZEB is a realistic possibility that uses today’s technologies combined with an integrated design process.

For NZEBs, every watt counts, as saving a single continuous watt with energy efficiency equates to avoiding $33 in PV capital costs.

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bibliography

http://www.nibs.org/

http://www.nrel.gov/

Building Envelope (http://www.ornl.gov/sci/ees/etsd/btric/)

Solar Energy Technologies (http://www.ornl.gov/sci/eere/research_solar.shtml)

Cooling, Heating and Power (http://www.ornl.gov/sci/engineering_science_technology/cooling_heating_power/)

Whole-Building & Community Integration Residential, Commercial & Industrial Energy Efficiency (http://www.ornl.gov/sci/ees/etsd/btric/residential.shtml

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