Net-Zero Energy for Buildings – ASHRAE Engineering Design and Construction

Integration: Net-zero energy design

ASHRAE has a goal: net-zero energy for all new buildings by 2030. What do engineers need to know to achieve this goal on their projects?

Source: www.csemag.com

>”As net-zero energy and low-energy design projects become more prevalent, engineers must be prepared to collaborate with all members of a project team including architects, energy specialists, lighting designers, builders, and owners in order to accomplish net-zero energy goals with little to no cost premium. Is this possible today or will it take another 10 or more years to get there?

There are many examples of completed projects demonstrating that not only is this possible, but it has been done in all regions of the country using readily available building products and common construction methods. So what’s the secret? It’s all about the design.

Net-zero energy defined

The term “net-zero energy” is abundantly used, but a single universally accepted definition does not exist. In general terms, a net-zero energy building (NZEB) has greatly reduced energy needs achieved through design and energy efficiency, with the balance of energy supplied by renewable energy. In an effort to clarify the issue, the National Renewable Energy Laboratory (NREL) published a paper in June 2006 titled “Zero Energy Buildings: A Critical Look at the Definition,” in which it defined the following four types of NZEBs:

Net Zero Site Energy: A site NZEB produces at least as much renewable energy as it uses in a year, when accounted for at the site.Net Zero Source Energy: A source NZEB produces (or purchases) at least as much renewable energy as it uses in a year, when accounted for at the source. Source energy refers to the primary energy used to extract, process, generate, and deliver the energy to the site. To calculate a building’s total source energy, imported and exported energy is multiplied by the appropriate site-to-source conversion multipliers based on the utility’s source energy type.Net Zero Energy Costs: In a cost NZEB, the amount of money the utility pays the building owner for the renewable energy the building exports to the grid is at least equal to the amount the owner pays the utility for the energy services and energy used over the year.Net Zero Energy Emissions: A net-zero emissions building produces (or purchases) enough emissions-free renewable energy to offset emissions from all energy used in the building annually. Carbon, nitrogen oxides, and sulfur oxides are common emissions that zero-energy buildings offset. To calculate a building’s total emissions, imported and exported energy is multiplied by the appropriate emission multipliers based on the utility’s emissions and on-site generation emissions (if there are any).

A subsequent paper was published by NREL in June 2010 titled “Net-Zero Energy Buildings: A Classification System Based on Renewable Energy Supply Options,” where four classifications of NZEBs were defined:

NZEB:A: Building generates and uses energy through a combination of energy efficiency and renewable energy (RE) collected within the building footprint.NZEB:B: Building generates and uses energy through a combination of energy efficiency, RE generated within the footprint, and RE generated within the site.NZEB:C: Building generates and uses energy through a combination of energy efficiency, RE generated within the footprint, RE generated within the site, and off-site renewable resources that are brought on site to produce energy.NZEB:D: Building uses the energy strategies described for NZEB:A, NZEB:B, and/or NZEB:C buildings, and also purchases certified off-site RE such as Renewable Energy Certificates (RECs) from certified sources. […]

Integrated building design

Integrated building design is a process that promotes holistic collaboration of a project team during all phases of the project delivery and discourages the traditional sequential philosophy. According to ASHRAE, the purpose of the integrated design process is to use a collaborative team effort to prepare design and construction documents that result in an optimized project system solution that is responsive to the objectives defined for the project. […]

Commissioning is an important part of every project, and for NZEB projects the commissioning authority should be a member of the design team and involved throughout the design process. […]”<

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India’s First LEED’s Green Building targets “Net Zero” with High Efficiency Solar Power

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New Delhi, India (SPX) Sep 19, 2013 – SunPower has announced that Swadeshi Civil Infrastructure has completed the installation of a 930-kilowatt (kW) SunPower solar system on the rooftop of the Indira Paryavaran Bhavan building…

Duane Tilden‘s insight:

>The state-of-the art landmark will be India’s first net zero energy building. Its design emphasizes conservation featuring trees to reduce adverse environmental impact, adequate natural light and shaded landscaped areas to reduce ambient temperature.

The building is targeted to achieve Platinum from the Leadership in Energy and Environmental Design green building rating system, known as LEED INDIA. It also is expected to receive a five star Green Rating for Integrated Habitat Assessment from the rating system developed by the Energy and Resource Institute and supported by the Ministry of New and Renewable Energy, the nodal ministry of Indian government.<

See on www.solardaily.com

Quantitative Analysis of Factors Contributing to Urban Heat Island Intensity

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Ryu, Young-Hee, Jong-Jin Baik, 2012: Quantitative Analysis of Factors Contributing to Urban Heat Island Intensity. J. Appl. Meteor. Climatol., 51, 842–854.

Duane Tilden‘s insight:

>This study identifies causative factors of the urban heat island (UHI) and quantifies their relative contributions to the daytime and nighttime UHI intensities using a mesoscale atmospheric model that includes a single-layer urban canopy model. A midlatitude city and summertime conditions are considered. Three main causative factors are identified: anthropogenic heat, impervious surfaces, and three-dimensional (3D) urban geometry. Furthermore, the 3D urban geometry factor is subdivided into three subfactors: additional heat stored in vertical walls, radiation trapping, and wind speed reduction. To separate the contributions of the factors and interactions between the factors, a factor separation analysis is performed. In the daytime, the impervious surfaces contribute most to the UHI intensity. The anthropogenic heat contributes positively to the UHI intensity, whereas the 3D urban geometry contributes negatively. In the nighttime, the anthropogenic heat itself contributes most to the UHI intensity, although it interacts strongly with other factors. The factor that contributes the second most is the impervious-surfaces factor. The 3D urban geometry contributes positively to the nighttime UHI intensity. Among the 3D urban geometry subfactors, the additional heat stored in vertical walls contributes most to both the daytime and nighttime UHI intensities. Extensive sensitivity experiments to anthropogenic heat intensity and urban surface parameters show that the relative importance and ranking order of the contributions are similar to those in the control experiment.

Keywords: Urban meteorology

Received: May 7, 2011;<

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NASA – Ecosystem, Vegetation Affect Intensity of Urban Heat Island Effect

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NASA researchers studying have found that the intensity of the “heat island” created by a city depends on the ecosystem it replaced and on the regional climate.

Duane Tilden‘s insight:

I have measured the heat island effect in the Greater Vancouver area, specifically Metrotown, Burnaby to be in the order of 6 deg C, during a late summer evening.

>”The placement and structure of cities — and what was there before — really does matter,” said Marc Imhoff, biologist and remote sensing specialist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The amount of the heat differential between the city and the surrounding environment depends on how much of the ground is covered by trees and vegetation. Understanding urban heating will be important for building new cities and retrofitting existing ones.”

Goddard researchers including Imhoff, Lahouari Bounoua, Ping Zhang, and Robert Wolfe presented their findings on Dec. 16 in San Francisco at the Fall Meeting of the American Geophysical Union.

Scientists first discovered the heat island effect in the 1800s when they observed cities growing warmer than surrounding rural areas, particularly in summer. Urban surfaces of asphalt, concrete, and other materials — also referred to as “impervious surfaces” — absorb more solar radiation by day. At night, much of that heat is given up to the urban air, creating a warm bubble over a city that can be as much as 1 to 3°C (2 to 5°F) higher than temperatures in surrounding rural areas.

The impervious surfaces of cities also lead to faster runoff from land, reducing the natural cooling effects of water on the landscape. More importantly, the lack of trees and other vegetation means less evapotranspiration — the process by which trees “exhale” water. Trees also provide shade, a secondary cooling effect in urban landscapes.

Using instruments from NASA’s Terra and Aqua satellites, as well as the joint U.S. Geological Survey-NASA satellite Landsat, researchers created land-use maps distinguishing urban surfaces from vegetation. The team then used computer models to assess the impact of urbanized land on energy, water, and carbon balances at Earth’s surface. <

See on www.nasa.gov

Integration: Net-zero energy design | Consulting-Specifying Engineer

See on Scoop.itGreen Building Design – Architecture & Engineering

-ASHRAE has a goal: net-zero energy for all new buildings by 2030. What do engineers need to know to achieve this goal on their projects?

Duane Tilden‘s insight:

>As net-zero energy and low-energy design projects become more prevalent, engineers must be prepared to collaborate with all members of a project team including architects, energy specialists, lighting designers, builders, and owners in order to accomplish net-zero energy goals with little to no cost premium. Is this possible today or will it take another 10 or more years to get there?

There are many examples of completed projects demonstrating that not only is this possible, but it has been done in all regions of the country using readily available building products and common construction methods. So what’s the secret? It’s all about the design.<

See on www.csemag.com

Scientists Adding Color to Solar Panels

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If you have noticed the design and layout of solar panels around, you would have thought a minute or two about its aesthetics. Though not too bad, the dark

Duane Tilden‘s insight:

>The Institute is developing a SIS (semiconductor-insulator-semiconductor) variety solar panel. The package consists of a silicon substrate which absorbs light and converts it into electricity.[…]

The change in color does not make solar cells less efficient. The cell’s working is also not affected by the thickness of the conductive oxide layer. The SIS cell has the same simulated efficiency of around 20%.

The technology might later on use a type of inkjet printing that deposits the oxide layer with more flexibility, which would allow complex designs too. With this, solar cells could turn out to be part of beautiful architectural designs in future.<

See on www.greenpacks.org

The 21st century data center: You’re doing it wrong | ZDNet

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Outdated designs are keeping data centers from reaching their full potential.

Duane Tilden‘s insight:

>One example of this are data centers that use raised floors for cooling. Many IT pundits have discredited this method of cooling as wasteful, including Schneider Electric’s territory manager for the Federal government and the ACT, Olaf Moon.

[…]

Cappuccio notes that engineering firms that are consulted to build data centers know about the newer and more efficient ways to do things. But rather than try something new, they prefer the stock standard cookie-cutter approach to creating data centers because it’s fast and easy, he said.

[…]

“I’ve seen a lot of data centers being built that are too big,” says Cappuccio. “We’re finding people with data centers that are three to four years old when they realise they have far too much space, and are still providing air conditioning to those areas. So they begin to shrink them, putting up walls, bringing down the ceiling so they don’t air condition the extra space.”

See on www.zdnet.com