Tag Archives: building technology

Five Cutting-Edge Building Materials to Watch

The following materials technologies are making significant headway this year. This motley collection of innovations, which includes clothing made from synthesized spider threads, consumer products bio-engineered from discarded shrimp shells, and a bridge built entirely by robots, represents the culmination of years—sometimes decades—of research.

Solar-Thermal Cladding
The Solar Activated Façade, a cladding system that combines wood louvers and back-vented glazing, is particularly appealing. Designed as a thermal storage device for use in colder climates, the system consists of prefabricated panels that can be installed onsite via an aluminum cladding mounting system. The wood slats are angled to deflect the summer sun while inviting the winter sun’s radiant energy into an interior cavity, storing diurnal winter heat long into the night to reduce heat loss from interior spaces. Depending on the type of insulated backing used, the Solar Activated Façade can lead to R-values ranging from 65 to 150. The system was originally developed by Switzerland-based architect Giuseppe Fent, and has been commercially available in that country for approximately 15 years as Lucido Solar AG.

Synthetic Spider Thread
One of the most captivating arguments in Janine Benyus’ celebrated book Biomimicry: Innovation Inspired by Nature (HarperCollins, 1997) concerned her aspiration for modern industry to create materials as strong, elegant, and versatile as spider silk. Since then, Spiber, Inc. has since taken the reins in creating a synthetic spider thread it calls Qmonos (based on kumonosu, the Japanese term for a spider web). The fibroin protein that imparts Qmonos with its dragline, silk-like quality is not made from goats’ milk, but rather bio-engineered bacteria and recombinant DNA.

Structural 3D Printing
Originally scheduled to start construction late last year, the Dutch designer Joris Laarman’s MX3D Bridge should begin taking shape this year. As the world’s first 3D-printed bridge, the highly anticipated steel structure will be built using the Netherlands–based MX3D’s multi-axis metal-printing technology. This process is driven by industrial robots fitted with welding machines that can print lines of various metals in mid-air, starting from an anchored surface—similar to drawing a structure in space—by incrementally fusing molten metal in short lengths and allowing it to cool. Working in collaboration with Autodesk and European construction company Heijmans, Laarman has long been developing plans for the autonomously constructed pedestrian bridge, which will span the Oudezijds Achterburgwal canal, one of Amsterdam’s oldest man-made waterways.

Self-Healing Concrete
Also undergoing testing is a collection of self-healing concrete technologies. Through a project called Materials for Life (M4L), researchers from the School of Engineering at the University of Cardiff, in Wales, are conducting the first major trial of these materials in the U.K. The team, which also includes scientists from the University of Bath and the University of Cambridge, both in England, will evaluate the viability of three types of self-healing concrete: one with shape-memory polymers activated by electrical current, one with healing agents made from organic and inorganic compounds, and one with capsules containing bacteria and healing agents. M4L’s goal is autonomous infrastructure—roads, tunnels, bridges, and buildings—that can repair themselves without human intervention. The team’s goal is to “create sustainable and resilient systems that continually monitor, regulate, adapt, and repair themselves without the need for human intervention,” said Cardiff professor and M4L principal investigator Bob Lark in a press release. This is especially important given the estimated 40 billion pounds ($57.8 billion) spent annually on the concrete-intensive maintenance and repair of these structures in the U.K., the team says. The M4L trial is underway at a road-construction site near the A465 highway in South Wales, where the researchers can view the performance under real-world conditions.

Finally, research continues to bring us closer to tomorrow’s plastic. Scientists at Harvard University’s Wyss Institute for Biologically Inspired Engineering have developed a new bioplastic made from discarded shrimp shells. Using the remarkably tough yet flexible natural chitin, or insect cuticle, Wyss founding director Don Ingber and postdoctoral fellow Javier Fernandez have created thin films with the same structure and composition as chitin. Made using the processed derivative chitosan from shrimp shells, the new plastic matches aluminum in strength at only half the weight. It is also biocompatible, biodegradable, inexpensive, and may be molded to a variety of 3D shapes. The researchers are optimistic about the material’s ability to replace fossil fuel–based plastics in consumer and medical applications. This is critical given the proliferation of non-biodegradable plastic waste discarded every year, much of which is polluting the world’s oceans.

Architectural Acoustics

Architectural acoustics (also known as room acoustics and building acoustics) is the science and engineering of achieving a good sound within a building and is a branch of acoustical engineering. The first application of modern scientific methods to architectural acoustics was carried out by Wallace Sabine in the Fogg Museum lecture room who then applied his new found knowledge to the design of Symphony Hall, Boston. Continue reading

What is Aerogel Insulation?

Aerogel is a low density solid state material derived from gel in which the liquid component of the gel has been replaced with gas. The result is an extremely low density solid with several remarkable properties, most notably its effectiveness as thermal insulation. Continue reading

Top Five Green Building Mistakes

How to avoid the five most common errors builders make when it comes to energy, health, and resource efficiency.

While green building technology continues to improve and new green products continue to evolve, they’re only “lipstick on a pig” if the home isn’t also energy efficient, built to last, healthy, safe, and affordable to maintain. Continue reading

Glass Block Makes a Comeback

Glass unit masonry has been used more frequently in the last few years for several good reasons. It offers various levels of light transmission into buildings and, depending on the pattern or color in the glass block, can also provide more privacy than conventional windows. Glass block are low maintenance, durable and provide energy efficiency comparable to double pane windows. Continue reading

Duct Insulation Primer

Insulation is applied to ductwork to enhance thermal performance and prevent condensation and dripping. Duct thermal performance needs enhancement since air transported through a supply duct is at a temperature different than that of the surroundings. Insulation reduces the rate of thermal loss to those surroundings. Without insulation, the air would need extra heating or cooling in order to arrive at the design supply air temperature. Return air ducts only need to be insulated if they pass through environments that adversely affect the return air temperature. Exhaust air ducts normally do not need insulation. Supply air ducts may be left un-insulated if they run exposed through the space being conditioned; this arrangement also reduces system first cost.

Insulation prevents condensation and dripping from ducts. Un-insulated cold air ducts very often have surface temperatures below the local dew point. At this temperature, condensate will form and eventually drip off, causing an uncontrolled accumulation of moisture on the outside surface of the duct. Duct insulation eliminates the formation of condensate and consequently prevents rusting and staining.

Extra heating (or cooling) energy required to compensate for reduced thermal performance of un-insulated duct has a negative effect on the HVAC system’s life-cycle cost. Therefore, duct insulation always presents an optimization problem. Since insulated duct costs much more than un-insulated, the recommended air velocity becomes a key factor in optimization. For instance, a higher air velocity reduces duct surface area and thus insulation cost.

Because of the relatively small temperature differences between supply air ducts and the spaces through which they ductwork are routed, a one-inch-thick fiberglass blanket is almost always sufficient. Insulation should be wrapped around the duct’s exterior. A protective cover with a vapor barrier such as an aluminum foil, referred to as FKS, should be included in insulation specifications. Care must be exercised to protect exterior insulation integrity where insulation comes in contact with hangers, supports, and other structural members. Interior duct insulation (lining) should not be used in laboratory or cleanroom applications because the insulation tends to entrain microscopic particles into the airflow.

Special consideration must be given to ducts exposed to weather. Lagging materials or heavy metal covers over the insulation are commonly used to protect ductwork. A life-cycle cost analysis may be necessary to determine optimum insulation thickness when ducts encounter temperature extremes.

All About Lighting Controls

Use lighting controls to automatically turn lights on and off as needed, and save energy. Of course you can save energy by turning off lights when they’re not needed, but sometimes we forget or don’t notice that we’ve left them on.

The most common types of lighting controls include:

  • Dimmers
  • Motion, occupancy, and photosensors
  • Timers.

Before purchasing and using any lighting controls, it’s a good idea to understand basic lighting terms and principles. Also, it helps to explore your indoor and outdoor lighting design options if you haven’t already. This will help narrow your selection.

Dimmer Controls

Dimmer controls provide variable indoor lighting. When you dim light bulbs, it reduces their wattage and output, which helps save energy.

Dimmers are inexpensive and provide some energy savings when lights are used at a reduced level. They also increase the service life of lightbulbs significantly. However, dimming reduces an incandescent bulb’s lumen output more than its wattage. This makes the bulbs less efficient as they are dimmed.

Dimmers and CFLs

Unlike incandescents, compact fluorescent lamps (CFLs) do not lose their efficiency with dimming. Some CFLs are compatible with standard dimmers, which will be indicated on the package. Others require special dimming ballasts and bulb holders. Fluorescent dimmers are dedicated fixtures and bulbs that provide even greater energy savings than a regular fluorescent bulb. Dimming a CFL that is not designed to work with a dimmer switch is not recommended, as this can shorten its life significantly.

You can change the lightbulbs and ballasts in fluorescent lighting fixtures rather than replace them.

Dimmers and LEDs

Some light-emitting diode (LED) lightbulbs can be used with dimmers. LED bulbs and fixtures must be designed for dimming, and you may need to replace existing dimmer switches with ones that are compatible with an LED lighting product. The packaging or accompanying instructions will indicate if the product is dimmable and which dimmer products are compatible. Fully compatible LED dimmers are expected to become more common as the LED industry expands.

Motion Sensor Controls

Motion sensors automatically turn outdoor lights on when they detect motion and turn them off a short while later. They are very useful for outdoor security and utility lighting.

Because utility lights and some security lights are needed only when it is dark and people are present, the best way to control might be a combination of a motion sensor and photosensor.

Incandescent flood lights with a photosensor and motion sensor may actually use less energy than pole-mounted high-intensity discharge (HID) security lights controlled by a photosensor. Even though HID lights are more efficient than incandescents, they are turned on for a much longer period of time than incandescents using these dual controls.

HID lightbulbs don’t work well with just a motion sensor, as they can take up to ten minutes to produce light.

Occupancy Sensor Controls

Occupancy sensors detect indoor activity within a certain area. They provide convenience by turning lights on automatically when someone enters a room, and save energy by turning lights off soon after the last occupant has left the room. Occupancy sensors must be located where they will detect occupants or occupant activity in all parts of the room.

There are two types of occupancy sensors: ultrasonic and infrared. Ultrasonic sensors detect sound, while infrared sensors detect heat and motion. In addition to controlling ambient lighting in a room, they are useful for task lighting applications such as over kitchen counters. In such applications, task lights are turned on by the motion of a person washing dishes, for instance, and automatically turn off a few minutes after the person leaves the area.

Photosensor Controls

You can use photosensors to prevent outdoor lights from operating during daylight hours. This can help save energy because you don’t have to remember to turn off your outdoor lights.

Photosensors sense ambient light conditions, making them useful for all types of outdoor lighting. These light-sensitive controls are less effective inside the home because lighting needs vary with occupant activity rather than ambient lighting levels. Many LED nightlights, however, have this feature built in which makes them effective and easy to use.

Timer Controls

Timers can be used to turn on and off outdoor and indoor lights at specific times. There are two types of timers: manual timers, which plug into an electrical outlet for controlling objects such as lamps or light strings; and in-wall programmable digital timers (which look like digital thermostats), which automate indoor or outdoor lighting.

Programmable timers are not often used alone for outdoor lighting because the timer may have to be reset often with the seasonal variation in the length of night. However, they can be used effectively in combinations with other controls. For example, the best combination for aesthetic  lighting may be a photosensor that turns lights on in the evening and a timer that turns the lights off at a certain hour of the night (such as 11 p.m.).

For indoor lighting, timers are useful to give an unoccupied house a lived-in look. However, they are ineffective for an occupied home because they do not respond to changes in occupant behavior, like occupancy sensors.

Using Timers with CFL and LED Lighting

Timing controls work well with CFL and LED lightbulbs, as they do not interrupt the circuitry. This is especially true with manual timers that use pins for setting the on and off times.

  • Manual timers: compatible with LED, CFL, and incandescent lighting
  • Programmable digital timers: check the package label to be sure it is compatible with the type of lighting you want to use.