I can remember 30 years ago receiving samples of the latest, greatest phase-change material. As I recall, it was a eutectic salt product that came packaged in sealed, black cans, ready for installation in passive solar buildings. While a great idea, these products were expensive and didn’t hold up well. Phase Change Energy Solutions appears to be changing those equations with its biobased, biodegradable BioPCM mats.

Phase-change materials (PCMs) use a quirk of physics to aid in thermal storage. When you warm up a solid material (like ice), its temperature rises steadily until it nears the melting point. At that point, the temperature remains roughly the same as the material continues to absorb heat; the process of changing phase from solid to liquid absorbs a lot of energy, called latent heat. Once the material is entirely melted, its temperature resumes rising. When you cool down and freeze a liquid, the same process happens in reverse, releasing stored energy.

EBN’s recent feature article, “LEDs: The Future Is Here,” we covered the long lifespan and impressive energy efficiency of LED lighting while also discussing the challenges LEDs still pose. LEDs are particularly strong in outdoor area lighting, however, an area where LED luminaires such as EvoLucia Lighting’s SCH Cobra Head provide energy savings and may even provide superior light quality over alternatives.

Outdoor LED area lighting is used primarily for safety and security on parking lots and walkways. Its most common competitors are high-pressure sodium (HPS) and metal halide (MH), but HPS with its orange glow is falling out of favor, while LEDs are gaining market share. Quality LED luminaires can provide a more efficacious, directed, uniform light, capable of being controlled by dimmers and motion detectors, which is important because these lights are on continuously night after night. The energy required to run these lights can be close to a third of a building’s electrical lighting load, according to Nancy Clanton, founder of the lighting design firm Clanton & Associates.

The Powerhouse shingle is designed to be installed by roofers and integrate seamlessly into a typical asphalt-shingle roof. For the foreseeable future, the systems will be available only through handpicked homebuilders and authorized dealers—primarily roofing companies.

By Peter Yost & Martin Solomon

We ask even more of our doors than we do our windows; we use them more, slam them more, load their thresholds with feet (human, pet, and even piano…), and typically secure them at just one point (the lockset) along their longest dimension. We expect sustained performance and security, and we would like them to have good insulation value and keep drafts out as well.

BuildingGreen announced its tenth annual Top-10 Green Building Products during the 2011 Greenbuild conference in Toronto. The award highlights the most forward-looking products reviewed in EBN and featured in GreenSpec throughout the year.

According to David Roberts, director of marketing at Cypress Envirosystems, about 70% of existing commercial buildings have pneumatic thermostats. These thermostats contain a metal strip that bends one way when cold and another when hot, changing the air pressure in the system, which then opens and closes dampers in the mechanical system to let in conditioned air as needed. Though it is a reliable, proven technology that has been used for more than 100 years, pneumatic thermostats have a significant limitation: they are manual. “If you have an office or conference room that is not used after 4 p.m. but other people work until 8 p.m., you have to leave the entire building on,” said Roberts.

Direct digital controls (DDC) for HVAC are installed during construction in most new buildings, when access to walls and wiring is easier. Retrofitting digital controls into older buildings that contain pneumatic thermostats—which includes most buildings constructed prior to the mid-1990s—involves shutting down the building and tearing into the walls and ceilings to install the wiring and equipment. This can be impractical and expensive, particularly if asbestos is discovered during the process. With Cypress’s WPT system, facilities can simply take the old thermostat off the wall, remove the air pipes, reattach the pipes to the new thermostat, reinstall it, and calibrate the WPT. Then you set up the wireless network, which includes repeaters, controller, and hub (one wireless network can support up to 225 WPTs). Total installation time per WPT: 20–30 minutes.

By Evan DickNew lightweight drywall products have become widely available in the U.S. and Canada in the last year as major drywall manufacturers have entered the market. These products weigh 1.2–1.4 pounds per inch for 1⁄2" panels—a 25%–30% weight reduction from standard drywall.

The weight reduction is a significant advance for drywall installers, allowing for easier installation and less fatigue. Manufacturers have also been hinting that the product, which typically sells at a 5%–10% retail premium, is greener due to reduced transportation energy. According to the U.S. Geological Survey, the average American home contains eight tons of drywall. Assuming for the sake of illustration that the drywall for an average home travels 500 miles by truck, a 30% reduction in drywall weight—2.4 tons— would avoid the release of 424 pounds of carbon per home—the equivalent of burning 21 gallons of gasoline. That could start to add up if more of the 15 million tons of drywall produced and shipped every year in the U.S. switches to lightweight.

The pavers can be tinted with EnvironOxide pigment, an iron-oxide-based byproduct of soil remediation in areas with excessive runoff from abandoned coal mines. According to Lampus’s vice president for marketing, Bob Welling, “We also have the ability to use some percentage of recycled materials as an aggregate constituent, in place of sand and gravel.” Welling said that standard concrete pavers cost about $4/ft

2; including blast-furnace slag in the mix could add roughly 10%–20%. Including slag and custom-ordered recycled content might add as much as 30% to the cost, but it varies.

The heart of the Ritter XL system is the company’s evacuated tube. While similar to evacuated tubes made by other companies, the tubes used in the XL system are a larger diameter and are made specifically for large-scale use. Ritter increases their performance further by using a unique heat-transfer plate that works in tandem with a parabolic mirror behind the tube to capture sunlight and focus it back onto the collectors at a perpendicular angle—simulating mid-day conditions.

The tubes come preassembled into panels (most evacuated tubes are shipped separately) that put out an impressive Solar Rating and Certification Corporation (SRCC) OG-100-rated 55,000 Btu per day. These panels are modular, so they can be installed in a series of five before going parallel. According to Michael DiPaolo, president of Regasol USA, the company’s real-world collector efficiency should be even higher when compared to other collectors, since SRCC collector testing is done with water and not propylene glycol. Yet in the real world, other large-scale collectors most often use glycol and not water.

On a Renzo Piano-designed renovation and expansion for Harvard Art Museums, the University and the general contractor, Skanska USA, paid attention to something that all too often gets ignored, even on green projects: inefficient jobsite lighting. By replacing the typical incandescent light strings and metal halide lamps with a new low-voltage LED system from Clear-Vu, they expect to reduce lighting energy use by nearly 90%, saving $350,000 in electricity costs during the period of construction.

Energy is not the only savings opportunity: on a large construction job, it’s not unusual to have one or more licensed electricians doing nothing but changing light bulbs all day, every day. For this Harvard job the electrical contractor was able to reduce its budget for maintaining the jobsite lighting, translating into additional savings for the University, according to Paul Davey, MEP manager for Skanska.