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