ENERGY RETROFIT OF ORTLIEB’S BOTTLING HOUSE

HPB_Fall2018_Bates_p1smaller-8377a361 The Henry F. Ortlieb Bottling House built in 1948, was once part of the Ortlieb’s Brewing Company complex, a dense residential and commercial district north of Center City Philadelphia. © MICHAEL MORAN/OTTO

When architecture and research firm KieranTimberlake began the search for its own building in 2013, its partners were drawn to a former bottling house in Philadelphia’s Northern Liberties neighborhood. Constructed in 1948, the bottling house was part of a suite of historic buildings, most of which had been demolished to make way for new condos. The firm saw an opportunity to both save a piece of neighborhood history and design an imaginative, ambitiously sustainable retrofit.The building had been left to the elements for some time, but despite its state of disrepair the structure and envelope were intact and most of the renovation centered on replacing the roof and windows to make the building more efficient. Through life-cycle analysis, the firm found that adapting the existing structure significantly reduced environmental impacts when compared to constructing a new building.In addition to reusing the historic structure, the retrofit doubled down on the original design’s energy reducing strategies, including passive heating and cooling to maintain a comfortable work environment with a low energy profile. Two years after the move, occupants were comfortable and the building’s energy use was less than half that of a comparably sized office.

HPB_Fall 2018_Bates_p6 The large daylit studio is designed to support a flexible collaborative culture while incorporating original features and new systems.
© MICHAEL MORAN/OTTO

The building relies primarily on passive cooling to the point of the firm initially foregoing air conditioning during summer months. Such an ambitious strategy, especially in the face of Philadelphia’s hot and muggy summers, demonstrated the importance of post-occupancy evaluation and real-time tuning of mechanical systems. In search of a way to quickly, conveniently, and inexpensively generate user data to inform and improve building operations, the firm developed a custom comfort survey application, administering daily surveys to staff, which have proved key to running the building.The simple premise of creating a modern facility while maintaining the factory’s original aesthetic and structure, served as a consistent guide during the restoration. The result is a thoroughly modern and sustainable building that would be instantly recognizable to its original occupants.

Read more about this retrofit…

Figure 1 screenshot


Article reposted from: High Performing Buildings Magazine, Ortlieb’s Bottling House, by Roderick Bates.

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INTERNATIONAL ENERGY EFFICIENCY AT A CROSSROADS

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More than ever before, energy efficiency is central to the achievement of a range of policy goals, including energy security, economic growth and environmental sustainability.

Strong efficiency gains, despite the recent fall in energy prices, have had a significant impact on global energy demand, reducing consumers’ energy bills, holding back emissions growth and making energy systems more secure.

However, global progress has become dependent on yesterday’s policies, with the implementation of new policies slowing. If the world is to transition to a clean energy future, a pipeline of new efficiency policies needs to be coming into force. Instead, the current low rate of implementation risks a backward step.

The energy intensity of the global economy continues to fall

Global energy intensity – measured as the amount of primary energy demand needed to produce one unit of gross domestic product (GDP) – fell by 1.8% in 2016. Since 2010, intensity has declined at an average rate of 2.1% per year, which is a significant increase from the average rate of 1.3% between 1970 and 2010.

Take a look at the Changes in Global Energy Intensity Chart.

Energy efficiency is helping to reshape the entire energy system

In 2016, the world would have used 12% more energy had it not been for energy efficiency improvements since 2000 – equivalent to adding another European Union in the global energy market.

Among IEA member countries, efficiency improvements led to a peak in total energy use in 2007, and a subsequent fall to levels not seen since the 1990s.

Energy efficiency is bolstering energy security

Efficiency improvements since 2000 avoided $50 billion in additional spending on energy imports in IEA member countries in 2016. In Japan, for example, oil imports would have been 20% higher in 2016 and gas imports 23% higher had those efficiency gains not occurred.

The impact of efficiency on gas imports has been particularly pronounced in Europe. In Germany and the United Kingdom, Europe’s largest gas markets, energy efficiency improvements since 2000 resulted in gas savings in 2015 equivalent to 30% of Europe’s total imports from Russia.

Efficiency has also improved short-term energy security by reducing peak daily gas demand. Without energy efficiency improvements over the same period, the United Kingdom and France would have needed access to an additional 240 million cubic metres of daily gas supply during periods of peak demand.

Improved energy efficiency has reduced household expenditure on energy

Energy efficiency gains since 2000 helped households in several major economies avoid nearly $300 billion in additional spending on energy in 2016. For example, in Germany, France and the United Kingdom, household energy bills in 2016 were on average over $400 per capita lower than they would have been had energy efficiency not improved as it did since 2000.

Savings are also being made in large emerging economies, where demand for energy services is growing. For example, on average Chinese households would have spent 25% more on energy in 2016 if not for efficiency.

Policy implementation slowed in 2016, putting future energy efficiency gains at risk

The share of world final energy use covered by policies that mandate energy efficiency improvements grew to nearly 32% in 2016 – an increase of 1.4 percentage points on 2015, but still leaving 68% of global energy use uncovered.

In stark contrast with previous years, nearly all the 2016 increase in coverage was due to the continuing impact of existing policies, as old energy-using equipment was replaced. Just 1% of the increase was due to new policies, an historic low.

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This is the slowest policy progress since 2009. The IEA Efficiency Policy Progress Index (EPPI), which measures changes in the coverage and strength of mandatory energy efficiency policies since 2000, increased by half a point to 6.3 globally in 2016, compared with average increases of around 0.75 since 2010.

The slowdown in the EPPI was largely due to fewer new policies coming into force, a trend that continued in the first half of 2017. China, with an EPPI of 10.9 in 2016, has been the global leader in implementing mandatory efficiency policies in recent years, accounting for 70% of the increase between 2000 and 2016, mainly due to policies in the industrial sector.

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Stronger policy development and implementation is essential if the current level of efficiency gains is to be maintained or accelerated.If stated policy ambitions are to be met, governments must recognise the importance of developing and putting into force new and more ambitious policies.

Buildings

The energy efficiency of buildings has improved, but far more is possible

Energy efficiency in buildings continues to improve, thanks to policy action and technological advances. Policies have focused primarily on the building envelope, rather than heating and cooling equipment. There is considerable potential to achieve further energy savings by establishing standards.

Efficiency improvements of 10% to 20% are possible in most countries from appliances, equipment and lighting products that are already commercially available. There is strong global momentum towards more efficient lighting; by 2022, 90% of indoor lighting worldwide is expected to be provided by compact fluorescent lamps (CFLs) and light-emitting diodes (LEDs).

The future of energy efficiency

The global energy efficiency market continued to expand in 2016

Global investment in energy efficiency continued to grow in 2016, increasing by 9% to $231 billion. The rate of growth was strongest in China at 24%, though Europe is still responsible for the largest share of global investment.

Among end-use sectors, buildings still dominate energy efficiency investment, accounting for 58% of the world total in 2016, with most investment in that sector going to building envelopes, appliances and lighting.

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In addition, energy efficiency has become a tradeable commodity in several countries. In 2016, changes in policy drove up the market value of energy savings substantially in France and Italy, the world’s two biggest markets where savings, in the form of white certificates, are traded between energy providers that face obligations to achieve specified amounts of savings. Digital technology is expected to enhance the ability for energy efficiency to participate in electricity markets.

The deployment of connected devices is growing, which will impact energy efficiency

The number of household connected devices in use is growing rapidly.

These devices, which can be connected to networks and other devices, provide new opportunities for energy savings through more accurate control of consumption. By the end of 2016, half a billion smart meters, which track and display electricity use in real time, had been or were contracted to be installed. Among other benefits, smart meters can complement connected devices, allowing consumers to adjust energy use in response to changes in energy price.

Read the full report…

 


Repost from International Energy Agency, Energy Efficiency 2017, October 2017.

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ENERGY EFFICIENCY IN COMMERCIAL DEMAND-SIDE MANAGEMENT

commercial-hvac-clouds

Energy efficiency can enhance human health by reducing greenhouse gas emissions, improving indoor and outdoor air quality, and decreasing acid rain. The energy needed to run commercial and industrial buildings in the United States produces 19 percent of U.S. carbon dioxide emissions, 12 percent of nitrogen oxides, and 25 percent of sulfur dioxide, at a cost of $110 billion a year.

The commercial sector is in need of cost effective solutions to address the rising cost of energy and the health implications of energy use.  Once a facility has developed an energy baseline by tracking and measuring its energy use, it can begin to zero in on key areas of inefficiency and review potential energy reduction strategies with an eye for what will work given the financial resources of the organization. Improving the efficiency of energy end uses reduces both energy cost and greenhouse gas emissions – and is often called ‘demand-side management’.  A robust energy efficiency program is the foundation for a business to take its next step towards a cleaner energy portfolio – and is often called ‘supply-side management’.  Displacing the use of conventional energy with clean, renewable energy reduces GHG emissions and contributes to softening price volatility associated with oil, natural gas, coal and electricity generated from these fuels. Learn more about supply-side management.

Demand-Side Management

Demand-side management is a facilities management approach that involves ways to reduce the need for energy.  The key in demand-side management is conservation through system-wide energy conservation programs. These types of programs identify cost-effective procedures that reduce energy consumption and develop systematic programs of energy system efficiency improvements. Commercial facilities examine and analyze energy use to determine where it could be possible to cut back.

There are several key areas a commercial facility can target when looking for energy efficiencies. The following areas are the energy use categories laid out by EnergyStar and provide a useful framework for assessing opportunities for energy reduction:

Retrocommissioning

Commissioning involves ensuring that mechanical systems are designed, installed, functionally tested, and capable of being operated and maintained according to the hospital’s operational needs. Commissioning usually takes place when the building goes into service. Retrocommissioning involves the same process of reviewing systems alignment and optimization, but takes place at a later point in the building’s lifecycle—and can recalibrate systems to function more efficiently and effectively—reducing energy and improving operations.

Lighting

Lighting consumes close to 35 percent of the electricity used in commercial buildings in the United States and affects other building systems through its electrical requirements and the waste heat that it produces. Upgrading lighting systems with efficient light sources, fixtures, and controls can reduce lighting energy use, improve the visual environment, and affect the sizing of HVAC and electrical systems. Looking at the intensity of lighting in different areas—i.e. what levels of illuminance are appropriate for a clinical area vs. a supply closet—may also identify opportunities for modifications and greater efficiencies.

Supplemental Load Reduction

Supplemental load sources are secondary load contributors to energy consumption in buildings—typically people, computers, lights, and the building itself. These loads can adversely affect heating, cooling, and electric loads. However, the effect of supplemental loads can be controlled and reduced through strategic planning and implementing energy-efficient upgrades. With careful analysis of these sources and their interactions with HVAC systems, equipment size and upgrade costs can be reduced. These upgrades can increase HVAC energy savings and reduce wasted energy.The best ways to reduce supplemental loads include:

  • Reducing equipment energy use
  • Upgrading the building envelope by improving insulation, fenestration, and roofing

Air Distribution Systems

On average, the fans that move conditioned air through healthcare institutions account for about 8 percent of the total energy consumed by these buildings, so reductions in fan consumption can result in significant energy savings. A U.S. Environmental Protection Agency (EPA) study found that almost 60 percent of building fan systems were oversized by at least 10 percent, with an average oversizing of 60 percent. “Rightsizing” a fan system, or better matching fan capacity to the requirements of the load, is an excellent way to save energy in air distribution systems. There are also opportunities for energy-saving improvements to the air distribution system in four other categories:

  • Adjusting ventilation to conform with code requirements or occupant needs,
  • Implementing energy-saving controls,
  • Taking advantage of free cooling where possible, and
  • Optimizing the efficiency of distribution system components.

Heating and Cooling Upgrades

Heating and cooling systems account for a significant portion of a building’s energy use—typically about a quarter. However, it is possible to lessen this impact in both central and unitary systems by increasing their efficiency. Cooling systems generally have higher space-conditioning capacities than heating systems because waste heat from people, lighting, and office equipment supplies a large portion of a building’s heating requirement. Although their higher capacities often translate into more opportunities for savings from cooling systems, significant savings can still be had from heating systems.Many existing systems are oversized to begin with, so it may now be possible to justify replacing the current system with a properly sized one—or retrofitting it to operate more efficiently. When replacing system components, it is extremely important to size the equipment properly to meet current loads. Besides saving energy, proper sizing will likely reduce noise, lower first costs for equipment, and optimize equipment operation, which in turn reduces maintenance costs and extends equipment lifetime.

**The material above comes directly from Energy Star’s Building Upgrade Manual

A Staged Approach

Energy Star recommends a staged approach to energy efficiency, meaning that an organization would want to look at the efficiency mechanism categories above in sequential order. Energy Star points to the fact that many of these strategies build upon each other and can increase efficiencies in later strategies if the early strategies are completed first.

Purchase of Energy Efficient Products & Equipment

The US Department of Energy provides several energy efficiency fact sheets on buying energy efficient equipment including:

 


Resources

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FUTURECAST: GOODBYE WIFI, HELLO LIFI

We have all heard of WIFI, the wireless method of transferring data that has revolutionized the way we work, watch TV and play games, but what is LIFI? Light fidelity (LIFI) is likely to be the next stage in the natural evolution of in-home wireless internet technology.

Billed as the super-fast, secure and energy efficient successor to WIFI, LIFI uses light to transmit data wirelessly at speeds up to 100 times faster than WIFI. Invented by Harald Haas, professor of mobile communications at the University of Edinburgh, LIFI transmits data over the visible light spectrum, rather than the radio waves that are currently used by WIFI.

LIFI uses light to send wireless data embedded in its beam. A LIFI enabled device converts the beam of light into an electrical signal. The signal is then converted back into data. The device sends back data using invisible light. LIFI is high speed bi-directional and fully networked light communications.”

haas_LIFI

Above: Harald Hass the inventor of LIFI (image courtesy of Harald Haas / University of Edinburgh ).

As this spectrum is 10,000 times larger, LIFI is not only faster but also has the potential to transfer much larger volumes of data. As radio bandwidths become cluttered with ever increasing amount of data being transferred, this capacity could become vital.

Conceptually similar to morse code, LIFI works using standard off-the-shelf LEDs, meaning that every light source in every office or home has the potential to transfer data. While standard LED bulbs are controlled by a driver-circuit that can either switch the light off and on, for a LIFI system the driver-circuit encodes data and transmits it by switching the LED off and on at rates that are undetectable to the human eye. An optical sensor on your laptop or phone receives the data, which is then decoded.

Office_LIFI

Above: Every light source in every office or home has the potential to transfer data ( image courtesy of Sean Airhart).

Although this system requires LEDs to be turned on, it is possible to dim them below human visibility and still emit enough light to transmit data. Although this will utilise energy, overall combining the transfer of light and data in one system is a sustainable solution.

As light can’t travel through walls, the flow of data can be closely controlled on an optical network, meaning that LIFI could be more secure than WIFI, which can be vulnerable to attack. LIFI doesn’t cause electromagnetic interference, meaning it can be used in sensitive areas such as hospitals, airplanes and nuclear power plants, which is another advantage of the system.

Optical sensor_LIFI

Above: LIFI technology is available now (image courtesy of Pure LIFI ).

Whilst LIFI may sound futuristic, the technology is available now. Since Professor Haas first demonstrated a working prototype in 2011 LIFI has developed rapidly. The first LIFI bulb is now commercially available with the system set to installed in an office in Paris later this year.

Despite the potential benefits, LIFI’s adoption is currently restricted by its high cost in comparison to WIFI, as the technology is still in its infancy. However, as demand rises, it is expected that the cost of LIFI will fall and its adoption will increase.

Skyline_whatisLifi

Above: Buildings could be built with one optical network that provides both light and data.

For the construction industry the impact may be sizeable as buildings could be built with one optical network providing both light and data reducing cost and installation time. The technology may also impact the shape of buildings as offices and homes are designed to best take advantage of optical data transfer.

 


Repost from The B1M, What is LIFI?, April 2017, with some modifications.

 

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WHAT IS KINETIC PAVING?

Photo courtesy of pavegen.com

Kinetic paving draws usable energy from footsteps. One of the companies leading the kinetic pavers charge, London-based Pavegen, said the technology works using electromagnetic induction generators, which vertically displace from the weight of human footsteps. That displacement motion creates the energy, which is then fed to generators as usable electricity. A single footstep can power an LED street lamp for 30 seconds, according to CNN.

All motion generates kinetic energy, and until recently that energy outputted by the countless billions of human footsteps taken every day has gone to waste. The technology to harvest that energy on a large scale has potentially world-changing implications, opening the possibility of generating electricity using one of the cleanest and most plentiful energy sources on the planet. The technology has been proven viable through installations in more than 100 sites worldwide.

Pavegenhas developed this special energy-harvesting tile – made from 95% recycled tires – that flexes by 5mm when stepped on, resulting in up to 8 watts of kinetic energy over the duration of the footstep. Every step is good for about 3 joules of energy, which could light a LED streetlamp for 30 seconds. Enough tiles and enough footsteps can create enough energy to be stored in batteries, or help power electrical items.

Each tile boasts unique wireless communications technology too. It uses only 1% of its power to transmit data about the number of footfalls and energy generated. This means city officials and business types can see how many people are passing through an area, and then make smart decisions about the way the extra power is used.

Dubbed the ‘world’s first smart street’, the tiles now power London’s Bird Street– aptly providing birdsong by day, and light at night. The paving here sports a new triangular tile, providing 20 times more powerthan Pavegen’s early versions.

The tech has already appeared at some pretty big events – Pavegen partnered up with Google for Berlin’s 2017 Festival of Lights, creating an installation to convert footsteps into off-grid energy. The effect was a synchronised lighting display across a record-breaking 26-square metres. The footfall lit up 176 light panels embedded in its walls and generated over 100,000 joules of energywithin the first 3 days.

And 12 tiles were installed along the walking route to the Olympic Park in 2012. Pavegen estimated over the course of the Games the tiles harvested energy from more than 12m footsteps, generating 72m joules of energy – enough to charge 10,000 mobile phones for an hour! The electricity was put to more communally beneficial use though, powering the lights in nearby West Ham tube station for 5 hours each night.

The tiles were also installed over a 25-metre distance at the start point of the Paris Marathon, as well as other key points en route. During the race, runners and bystanders generated nearly 5 kilowatts of electricity, enough to power a laptop for 52 hours, drive an electric car for 15 miles or light up a village in a developing nation for an entire day.

Another example is the installation under a football pitch in Rio de Janeiro, powering the floodlights. Pavegen aligned with the Shell #makethefuture campaign, to create a world’s first viral project that inspires an entire community through sport, by supporting bright energy ideas.

Ultimately, Pavegen hopes to make the tiles as affordable as regular floor tiles, and see them installed in offices, schools and public spaces around the world. The technology has come under some criticism because, well, it’s not as powerful as conventional electricity sources. The average person will walk 150 million steps in their lifetime, so in theory, that’s only enough to power the average family home for 3 weeks. But…combine all the steps of all the people on the planet, and we’re talking about a serious contribution to sustainable energy.

 


Sources

OVO Energy, What is Kinetic Pavement?

The B1M, 3 Awesome Construction Materials Innovations.

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SMOG-EATING BUILDINGS

domus-11-padiglione-italia

According to the World Health Organisation (WHO), air pollution is responsible for some 6.5 million deaths worldwide, mostly in and around major cities. And while steps are being taken to tackle the pollution at its source, “smog-eating” facades containing compounds that neutralise pollutants are one way in which the built environment can help mitigate the crisis.

Palazzo Italia (pictured left, click to enlarge), which debuted at the 2015 World’s Fair in Milan, is the first building made of concrete that’s designed to clear the air. The facade, a mixture of cement and titanium dioxide, captures nitrogen-oxide pollution and converts it into a harmless salt that easily rinses off the walls when it rains.

Palazzo Italia also consumes 40 percent less energy than a conventional building of its size, and emits zero air pollution. “We wanted the building to be an osmotic organism,” says lead architect Michele Molè—like a tree that breathes in carbon dioxide and exhales oxygen.

 

In addition to Italy, this has also been done in Mexico, The Netherlands, and in Britain. However, this approach can only be effective if it is widely adopted

In addition to buildings like Palazzo Italia, air-clearing concrete could pave sidewalks, highways, or other places with heavy pollution.

There are even proposals for “catalytic clothing,” in which nano-particles added to laundry detergent would turn people’s clothes into air cleaning surfaces.

Smart Home Security
Smart Home Security
The “smog-eating” installation at Mexico City’s Manuel Gea González Hospital (right image courtesy of Elegant Embellishments).

Resources:

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DAYLIGHTING & SUSTAINABLE DESIGN

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Daylighting is the controlled admission of natural light, direct sunlight, and diffused-skylight into a building to reduce electric lighting and saving energy. By providing a direct link to the dynamic and perpetually evolving patterns of outdoor illumination, daylighting helps create a visually stimulating and productive environment for building occupants, while reducing as much as one-third of total building energy costs.

A daylighting system is comprised not just of daylight apertures, such as skylights and windows, but is coupled with a daylight-responsive lighting control system. When there is adequate ambient lighting provided from daylight alone, this system has the capability to reduce electric lighting power. Further, the fenestration, or location of windows in a building, must be designed in such a way as to avoid the admittance of direct sun on task surfaces or into occupants’ eyes. Alternatively, suitable glare remediation devices such as blinds or shades must be made available.

Implementing daylighting on a project goes beyond simply listing the components to be gathered and installed. Daylighting requires an integrated design approach to be successful, because it can involve decisions about the building form, siting, climate, building components (such as windows and skylights), lighting controls, and lighting design criteria.

Description

The science of daylighting design is not just how to provide enough daylight to an occupied space, but how to do so without any undesirable side effects. Beyond adding windows or skylights to a space, it involves carefully balancing heat gain and loss, glare control, and variations in daylight availability. For example, successful daylighting designs will carefully consider the use of shading devices to reduce glare and excess contrast in the workspace. Additionally, window size and spacing, glass selection, the reflectance of interior finishes, and the location of any interior partitions must all be evaluated.

A daylighting system consists of systems, technologies, and architecture. While not all of these components are required for every daylighting system or design, one or more of the following are typically present:

  • Daylight-optimized building footprint
  • Climate-responsive window-to-wall area ratio
  • High-performance glazing
  • Daylighting-optimized fenestration design
  • Skylights (passive or active)
  • Tubular daylight devices
  • Daylight redirection devices
  • Solar shading devices
  • Daylight-responsive electric lighting controls
  • Daylight-optimized interior design (such as furniture design, space planning, and room surface finishes).

Since daylighting components are normally integrated with the original building design, it may not be possible to consider them for a retrofit project.

If possible, the building footprint should be optimized for daylighting. This is only possible for new construction projects and does not apply to retrofits. If the project allows, consider a building footprint that maximizes south and north exposures, and minimizes east and west exposures. A floor depth of no more than 60 ft., 0 in. from south to north has been shown to be viable for daylighting. A maximum facade facing due south is the optimal orientation. Deviation from due south should not exceed 15° in either direction for best solar access and ease of control.

With the building sited properly, the next consideration is to develop a climate-responsive window-to-wall area ratio. As even high-performance glazings do not have insulation ratings close to those of wall constructions, the window area needs to be a careful balance between admission of daylight and thermal issues such as wintertime heat loss and summertime heat gain. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) offers guidance on these ratios per climate zone in their Standard 90.1 energy code, but these are primarily minimal for thermal performance and do not consider admission of daylight.

A high-performance glazing system will generally admit more light and less heat than a typical window, allowing for daylighting without negatively impacting the building cooling load in the summer. This is typically achieved through spectrally-selective films. These glazings are typically configured as a double pane insulated glazing unit, with two 0.25 in. (6 mm) thick panes of glass that are separated by a 0.50 in. (12 mm) air gap. This construction gives the insulated glazing unit a relatively high insulation rating, or R-value, as compared to single pane glass. A low-emissivity coating is also often part of these high-performance glazing units, which further improves the R-value of the unit.

Types of Technology

Daylighting is an energy-efficient strategy that incorporates many technologies and design philosophies. It is not a simple line item, and can vary tremendously in scope and cost. Many elements of a daylighting implementation will likely already be part of a building design or retrofit (e.g. windows and light fixtures), but a successful daylighting system will make use of the following technology types and construction methods:

  • Exterior shading and control devices. In hot climates, exterior shading devices often work well to both reduce head gain and diffuse natural light before entering the work space. Examples of such devices include light shelves, overhangs, horizontal louvers, vertical louvers, and dynamic tracking of reflecting systems.
Illustration of visible transmittance: Glazing material is represented by a verticle line, there is a small arrow curved to the top right labeled absorbed and a large that begins on the top left and then breaks off into to ends as it hits the glazing material it then either keeps going through and is labeled transmitted or bounces off and is labeled reflective.
  • Glazing materials. The simplest method to maximize daylight within a space is to increase the glazing area. However, three glass characteristics need to be understood in order to optimize a fenestration system:
    • U-value: represents the rate of heat transfer due to temperature difference through a particular glazing material.
    • Shading coefficient: a ratio of solar heat gain of a given glazing assembly compared to double-strength, single glazing. (A related term, solar heat gain coefficient, is beginning to replace the term shading coefficient.)
    • Visible transmittance: a measure of how much visible light is transmitted through a given glazing material.

    Glazings can be easily and inexpensively altered to increase both thermal and optical performance. Glazing manufacturers have a wide variety of tints, metallic and low-emissivity coatings, and fritting available. Multi-paned lites of glass are also readily available with inert-gas fills, such as argon or krypton, which improve U-values. For daylighting in large buildings in most climates, consider the use of glass with a moderate-to-low shading coefficient and relatively high visible transmittance.

  • Aperture location. Simple sidelighting strategies allow daylight to enter a space and can also serve to facilitate views and ventilation. Typically, the depth of daylight penetration is about two and one-half times the distance between the top of a window and the sill.
  • Reflectances of room surfaces. Reflectance values from room surfaces will significantly impact daylight performance and should be kept as high as possible. It is desirable to keep ceiling reflectances over 80%, walls over 50%, and floors around 20%. Of the various room surfaces, floor reflectance has the least impact on daylighting penetration.
  • Integration with electric lighting controls. A successful daylighting design not only optimizes architectural features, but is also integrated with the electric lighting system. With advanced lighting controls, it is now possible to adjust the level of electric light when sufficient daylight is available. Three types of controls are commercially available:
    • Switching controls: on-and-off controls that simply turn the electric lights off when there is ample daylight.
    • Stepped controls: control individual lamps within a luminary to provide intermediate levels of electric lighting.
    • Dimming controls: continuously adjust electric lighting by modulating the power input to lamps to complement the illumination level provided by daylight.

    Any of these control strategies can, and should, be integrated with a building management system to take advantage of the system’s built-in control capacity. To take full advantage of available daylight and avoid dark zones, it is critical that the lighting designer plan lighting circuits and switching schemes in relation to fenestration.

Daylighting can be a viable, energy-efficient strategy in almost any climate, including traditionally overcast climates such as those found in parts of the Pacific Northwest. The technology can work in all building types as well, including commercial office buildings, most spaces within a school (i.e. classrooms, gymnasiums, media centers, cafeterias, and offices), retail stores, hospitals, libraries, warehouses, and maintenance facilities. A viable option for most building types and locations, it is important to consider that the architectural response to daylighting differs by building type, climate, and glare tolerability. Daylighting also has the potential to provide significant cost savings.

Read the full report…

 

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