Energy efficiency: The heat is on

Glass rainscreens and channel glass can help improve the energy efficiency of the building envelope. Photo © Said Elieh, Bendheim
Glass rainscreens and channel glass can help improve the energy efficiency of the building envelope.
Photo © Said Elieh, Bendheim

Rainscreens

Another method to help reduce energy dependency is through the use of rainscreens. A rainscreen system’s primary objective is to protect the envelope and deter rainwater from falling into a building’s exterior wall. By preserving the integrity of the structures, rainscreens safeguard their embedded carbon energy. They are also effective in managing air infiltration and heat transfer.

The rainscreen promotes energy savings due to the air cavity between the cladding and the exterior façade of the building, allowing for continuous ventilation. The enhanced ventilation improves the durability of the structure, as it remains dry. It also prevents heat buildup behind the cladding, making cooling the building easier in summer months.

Inova Schar Cancer Institute in Fairfax, Virginia, has a vertically and horizontally shingled glass rainscreen system. The rainscreen has an aesthetic and lighting role, but the shingled glass system acts as a permanent moisture shield.

The cladding’s continuous horizontal steel substructure sits atop a layer of rigid insulation, and has the ability to stop more than 90 percent of wind-driven rain from reaching the air and vapor barrier of the building. It also doubles as an anchor for the light-emitting diode (LED) lighting cable.

The shingled glass was engineered with a structural interlayer to use relatively lightweight 10-mm (3/8-in.) glass for large, 1.5 x 1.8-m (5 x 6-ft) cladding panels. The interlayer reinforces the glass so it can span under the imposed wind loads. The vertically and horizontally shingled panels are held in patented compression fittings, independent of each other, for ease and speed of installation.

Designing an energy-efficient building envelope requires extreme integration that accounts for sun positioning, building materials, climate, and the quality of construction. The envelope is just one part of the overall equation. While it may be a starting point in most projects, the ultimate efficiency is captured by the meshing of a wide range of products and components.

“An integrative, holistic approach is the best way to make sure the building is designed for maximum energy efficiency,” Overbey said. “When you look at everything, even the massing, we can get a sense of how it is going to be.”

All in

More and more architects are now embracing energy-efficient design. Forty-one percent of all U.S. architecture firms have committed to zero-carbon design by 2030.

Architects are not the only ones. The U.S. Green Building Council (USGBC), National Governors Association (NGA), and others have adopted the goals of the 2030 Challenge. Even the United States government now requires new federal buildings and major renovations to meet 2030 Challenge standards.

There are still challenges ahead. In the world of energy-efficient construction and building materials, manufacturers are just scratching the surface of what is needed for a permanent and complete overhaul. Energy savings must improve dramatically, and there is also a need for more diverse sources of energy efficiency.

Measurement is also essential. In 2013, the University of California Davis (UC-Davis) pledged to reduce its net GHG emissions for its physical plant and vehicle fleet to zero by 2025. The university monitors 200,000 data points that show how efficiently energy is being consumed. The details will help UC-Davis make strategic decisions for new energy systems and future purchasing decisions.

Perhaps the most pressing challenge, however, is the need to pivot quickly. The environmental impact on the planet has been well-documented, and the time is at hand where solutions need to be found and installed quickly. The planet is asking for a swift reversal in the way the global population goes about using its precious resources. Architects are on the frontline in ensuring that occurs.

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