Volume 50, Issue 2 - February 2015
From Envelope to Electrical
SageGlass supplied dynamic glazing for the Butler County Health Care Center in David City, Neb., helping provide an abundance of natural light.
What Is An
An integrated façade essentially is one that aims to maximize the usefulness of natural daylighting.
In her presentation at the GlassCon Global Conference in July 2014 (see the August 2014 USGlass, page 46), Helen Sanders, vice president of technical business development for SAGE Electrochromics Inc. defined integrated façades as a building design that has:
1. Effective daylighting design;
2. Energy efficient fenestration with a low U-factor (as appropriate for the climate zone) and dynamic solar control, including thermal comfort for occupants;
3. Dimmable lighting control;
4. Dynamic response for glare.
Today it may seem that the responsibility of integrated facades must rest in the designer’s hands. However, fabricators and glazing contractors that want to see today’s trend toward larger expanses of glass continue—even as energy codes grow more stringent—would be doing themselves a service by serving as a resource for designers even beyond the selection of the right glass.
“To me, the idea of integrated façade is the way you’re going to get more glass into buildings,” Sanders says. “When you integrate façades into lighting controls, for example, you have an energy store that can get you to net-zero without eliminating windows in buildings.”
Dynamic glass when tinted (below) can help control cooling costs during peak energy load periods. In its clear state (above), it allows for the transmission of natural light inside.
The Energy-Saving Driver
Glass may be the cladding of choice today, and net-zero buildings may still seem far off, but the future may tell a different story. Energy codes are becoming more stringent each cycle and more popular among building developers who tend to hold onto buildings (and their resulting energy costs) longer than they did a decade ago.
“Daylighting requirements have decisively grown in bellwether standards/rating systems such as Title 24 and LEED v4,” notes Brandon Tinianov, senior director of business development for View Inc. in Milpitas, Calif. “Further, quality daylighting and views are a key requirement in new standards such as the WELL Building Standard … We are in the very early days of the explosion of daylighting as a theme in building design.”
For the model building codes, glass and lighting are inextricably tied to one another. They recognize, as Sanders explains, that “as soon as you start to increase the window area, you start to increase the amount of daylight that comes into the space, so you can start to turn the lights off if you put lighting controls in a building. The energy used in the building actually goes down as you increase window area until you get to an optimum point … Then additional window area doesn’t help you; all it does is contribute to the heating and/or cooling load.”
Where in years past standards-writers have tried to limit the amount of glass in the wall, today the codes are focusing more on managing the light coming through that glass wall.
View Glass and the W Hotel partnered to showcase dynamic glass in the lobby/lounge area of the hotel to enhance guest experience and feature new technology to meet sustainability objectives. The glass was retrofitted into existing framing and set on an automated schedule that tinted the glass to various levels throughout the day.
“The model building codes require you to have lighting controls in a lot more spaces now,” Sanders says. California’s Title 24, she notes, is requiring lighting controls even in small private offices now. “Lighting controls basically reduce the intensity of the light when there’s enough daylight entering into a space. These controls read how much light is coming in and then turn down the lights appropriately.” Sanders adds that these code requirements are an open acknowledgement that glass can help buildings save energy—but only when part of a managed system. “If you don’t use dimmable lights, you’re not using that free energy [from daylight]. No one’s just going to get up and turn the lights off. It has to be automated.”
However, lighting controls aren’t the only method for “managing” usable daylight.
Take, for example, daylight redirecting film. 3M’s recently introduced film utilizes micro-replication to redirect light that would have originally hit the floor a few feet from the window up onto the ceiling, helping to light the room as deep as 40 feet from the window. The term “micro-replication” refers to microscopic structures that are able to redirect as much as 80 percent of light up onto the ceiling, providing more natural light.
Jon Mansheim, marketing manager for the 3M Renewable Energy Division, points out that the film can have a dramatic impact on a building’s use of natural light without requiring any additional work on the part of the installer or other systems.
“There are a variety of other technologies that require structural support,” Mansheim says. “The daylight redirecting film is a simpler technology that does not require structural elements to the curtainwall design ... so it can be easily integrated into new construction as well as retrofit.”
Daylight redirecting film from 3M is designed to move excess light close to the window and redirect it deeper into the building to increase the daylighting
The Automated Package
Integrated design is not just about lighting control. Glare control and shading are other important components. The key for all of these areas, however, is automation. And this automation is becoming more common as building-automation systems become more widely used.
“There’s always this trade-off between energy savings and human comfort,” Sanders says. “If you think about glare control, for example, the blinds come down, but that is intruding visual comfort. If you draw the blinds in winter, it’s blocking the path to solar heat gain. It’s also reducing the amount of daylight that comes in other times of year, so you’re going to put the lights on. There’s always a competition between optimum energy performance and performance for comfort.”
It’s one reason “lighting and glass have been almost fighting each other for the last 100 years,” says Rick Devine, technical support with Green Ballast, a Memphis-based manufacturer of lighting products that include daylight harvesting technology. As he explains, “We see the sun come up and the blinds go down when they should be wide open as daylight is essential to learning, production and to provide light. Now with all of the advancements in technology we are finally opening the shades and letting in the light, so now we have too much light. Daylight harvesting is the solution to that and can be achieved very simply and cost effectively.”
Finally, as Sanders explains, “An integrated façade also has to have high-performance fenestration because an integrated façade is not just about energy but also about creating a comfortable environment.”
When all of these conditions are met, the results can be dramatic.
“Daylighting a building correctly can reduce energy consumption for lighting loads by as much as 50 percent. In areas where the climate remains warmer, the reduction in heat load from lighting dramatically effects HVAC consumption as well,” says Devine. “It can be a very good and cost-effective way to decrease cost and save energy while reducing your carbon footprint as well.”
"Truly at the beginning, we should all be working together
Contractors Fit In
But as mentioned above, the site orientation, the specification of lighting controls, even the decision to use high-performance glazing all rest largely in the hands of the designer. What can the glass industry do to ensure that high-performance glass is used to its maximum potential as one part of an integrated system?
“…Glazing contractors can educate themselves on daylight design and managing the quantity of daylight,” Sanders says. “It’s not enough to put a lot of glass in the building and call it daylight. You certainly will get a lot of daylight but you won’t get good managed daylight; people will be too hot and there will be too much glare. You’ve got to figure how you’ll deal with glare and heat gain.”
Sanders says this can be as simple as being able to look at a drawing and asking “How are you going to deal with glare there? How are you going to manage that daylight?’ Or, “If you put in dimmable lighting controls, you can actually save some energy there.”
Not that architects may be receptive to the suggestions at first.
“Typically, the architect has already determined with the owner that they will be creating shade controls or harvesting daylighting concepts for the structure,” says Alana Sunness Griffith, FCSI, CCPR, vice president of Empirehouse Inc. in Mounds View, Minn. “With ideas and images from all over the Internet, and access to countless suppliers online, many designers seek these sources first so they can have the most advanced or unique designs for their buildings. They incorporate these ideas into their schematic drawings and then call us for advice and guidance on tested products and installation methods that can meet these needs.”
Today, more glazing contractors are brought in by designers for help with heat control than daylight management.
“More often we’re brought in for thermal performance than lighting, so it’s really going to require the architects to become aware that glazing contractors do have experience in lighting, even mechanical,” says Steve Landry, CEO of glazing contractor Custom Engineered Openings in Chula Vista, Calif. “Truly at the beginning, we should all be working together to come up with integrated systems that work well together as a process.”
Tinianov suggests that glazing contractors who focus on a more integrated delivery approach could get a competitive edge as daylight harvesting becomes more of a focus. “Glazing contractors can both promote their business and stay competitive in the market by having an in-house expert who understands low voltage networks and sensors,” he says. “While they traditionally worked only with glass alarms and door assists, now they also touch dynamic glass and lighting. With that expertise, glaziers can be a key member of the integrated envelope team.”
By keeping an eye toward the building systems that manage the impact of natural daylight glazing contractors might find they can influence the way buildings are designed—and maximize the amount of glass being used.
Megan Headley is special projects editor for USGlass magazine.
She can be reached at firstname.lastname@example.org.
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