Photovoltaic Systems

Despite the fact that we are now living in the 21st century, aerogel insulation seems like a material out of science-fiction. It is the lightest solid known, although by volume it is 99% air. It is breathable, but it doesn’t absorb water. It is incredibly strong for its weight. But most importantly, it is a fantastic insulator.

Some specialty insulation companies are now producing aerogel products that can be used for building insulation, although the largest market
for the material is still in industry. Aerogel insulation is also
exciting because it provides good benefit with a thin profile. For
instance, shipping-containers, which have a narrow width to begin with,
can be insulated without giving up too much valuable space to attaching
insulation to the walls.

A couple products are now available on the market, although their use is still constrained because of the relatively high cost of the material. Aspen Aerogels makes an aerogel blanket called Spaceloft, and Thermablok produces narrow strips of aerogel that may be a more cost-effective way of utilizing aerogel insulation without breaking the bank.

Aerogel is such a good insulator that a blowtorch on one side cannot light a match on the opposite side. While that is an extreme case, it demonstrates the effectiveness of the material. (And if you are a numbers geek, a typical aerogel insulation blanket has a thermal conductivity of 0.091 BTU-in/hr-sq.ft.-F at an ambient temperature of 32 degrees Fahrenheit, corresponding to an R-value of more than R-10 per inch. That’s nearly double the insulation value of the best rigid insulation boards currently available.)

Aspen Aerogels’ Spaceloft Insulation,
is a 57-inch wide roll of aerogel material available in 0.20 in. and
0.40 in. thickness. Spaceloft is a useful product for insulating
existing walls in retrofit situations where it is important to minimize
the amount of floor area lost to building up wall insulation. An old
brick building can be a beautiful thing, but brick makes a poor
insulator. Instead of building a new insulated wall against the
existing wall that would be 4″ thick (or more), a Spaceloft blanket
covered by drywall can achieve similar energy-efficiency in a wall
covering that is less than an inch thick.

According to Martin LaMonica of CNET, Spaceloft blankets have been used by the Rhode Island Housing Authority to retrofit a 50-unit housing complex that was built with no insulation in the 1940s.

Thermablok manufactures aerogel in 1-1/2″ wide strips rather than broad sheets. In stud wall construction, the cavity between the studs is filled with insulation, but the studs themselves can conduct heat and cold, a process known as “thermal bridging,” which reduces the thermal performance of the wall. By covering the studs with strips of aerogel insulation before the interior drywall or exterior sheathing is applied, the thermal bridging is broken, and the thermal performance of the wall can increase by 30% or more. This can be an efficient use of aerogel material in a cost-effective way.

Thermablok strips can be installed on the exterior of the studs during new construction, or can be applied on the interior during remodeling as well as new construction. This makes it suitable for energy efficiency retrofits. As with Spaceloft blankets, because Thermablok is so thin (about 1/4″ once installed), it can be used to improve performance without taking away great amounts of space from inside the building.

Thermablok strips have been used in the Solar Decathlon house from the California College of the Arts and the University of Santa Clara, California (also known as the Refract House shown above). Suggested retail price for Thermablok tape is $1.99/ft.

Photo credits: Thermablok, Aspen Aerogels, DOE.

Water efficiency is an important measure in green building everywhere, but in Australia — one of the driest countries in the world — water conservation is more widely practiced and water awareness is generally higher than it is in North America.  In addition to pioneering water efficiency, Australians have discovered some problems due to the use of efficient, low-flow fixtures.  One is the potential problem of “dry drains,” however, a new invention called the Drainwave aims to solve the problem. 

“Dry drains” is the term given for plumbing problems arising from the use of newer, more water efficient fixtures and facilities. Plumbing pipes have generally been designed and installed to transport solids with a flow of water. As low-flow fixtures have become more common, problems with plumbing systems have sometimes arisen.

Australian construction reporter Hartley Henderson noted in an article for Facilities Management, “Continual reductions of water flows in the plumbing systems of buildings, however, can result in ‘dry drains,’ whereby flows may be insufficient to effectively flush toilet discharges through the piping system. The situation is further compounded with a trend to extract greywater from plumbing systems for reuse.”  

Enter, the Drainwave. 

The Drainwave was featured on the Australian television show “The New Inventors,” where it won a People’s Choice award. The Drainwave is simply an inline accumulator that collects blackwater (sewage and wastes) and greywater (from sink drains) and discharges it through the sewer only when there is enough of a volume to propel the waste as needed.

According to the Drainwave website, “Using two inlet ports, the Drainwave collects greywater from general household use (sink, shower, washing machine, etc) and combines this outside the house with black water from the toilet. The combined waste water leaves the Drainwave and surges through the pipe network to the main sewer line to minimize blockages.“ 

Once 9.5 liters (2.5 gallons) have accumulated in the Drainwave, it automatically empties itself with enough volume to keep drain pipes from becoming blocked.

The Drainwave accomplishes its goal without use of additional water, which preserves the efficiency of low flow fixtures and other measures, while also allowing existing piping and infrastructure to continue to function as it was initially designed and built.  It’s not a pretty thing, it’s something meant to be hidden out of sight.  But it has the potential to avert a lot of unpleasant problems, particularly for water efficient buildings.

With the increasing adoption of LEED in green building, and the now mandatory water use reduction called for under LEED 2009 (and points available for water use reduction targets of 40% better than baseline), water efficiency is becoming more commonplace in the US. Similarly, European standards are also including water use efficiency as part of green building programs.

The Drainwave can be installed underground outside the house, making it possible to use in retrofit installations, or can be installed in uninhabited parts of the house.  Although this device is aimed at the residential market, versions to serve the commercial market can easily be anticipated.

[+] Video on the Drainwave website.

This year’s Innovation Pipeline at West Coast Green was relatively small.  In part this may reflect the state of the economy, which has lead to decreased investments in new building technologies.  Despite that, there are a few interesting technologies that have been brought to market recently or will hopefully be available soon.  Here’s a look at several products that may just change the future of this industry. 

1. H2Orb

The H2Orb from AquaOne Technologies is a small sphere with a display that connects to the water supply line and two remote sensors.  It detects leaks or overflows, and then sounds an alarm or shuts off the water or both.  At $125 it’s more expensive than low-end toilets, so why would a homeowner spend that kind of money?  It makes more sense to replace an old, leaky toilet with a new, low gallon-per-flush model. But the H2Orb was inspired by the needs of assisted living facilities and other institutional buildings where a leak or an overflow might go unnoticed for long periods.  Multiply a small leak by dozens or hundreds of toilets over days or weeks, and staggering amounts of water can be wasted.  It can also protect against damage by shutting off the water in the event of an overflow.  AquaOne says it can be installed in 7 minutes.

2. IceCold

Designed for large HVAC systems, IceCold is like anti-cholesterol medicine for refrigerant.  It works by reducing oil fouling in the coils and thereby increasing system efficiency.  It’s expensive, but it’s a one-time application, and they promise a 10% or better improvement by measuring efficiency before and after application.

3. SolarClover

Uniquely shaped solar panels from Armageddon Energy, the SolarClover is designed to be lighter, more flexible, and easier to install than traditional solar panels. The SolarClover system uses micro inverters on each cluster instead of a single inverter for the whole array (similar to the Solar in a Box system).  That means the home run is AC at lower voltages than a DC home run would be, and the overall system efficiency is less impacted by shading of a few panels.  Look for it on the market during 2010.

4. Stak Blocks

A new twist on straw bale construction, Oryzatech compresses rice straw (an agricultural waste product) into interlocking blocks.  Walls are bolted to the foundation with threaded rods running top to bottom through holes, which also provide vertical chases for electrical.  The resulting walls are R-50, fire-resistant, and provide better shear strength than a traditional sheathed 2×4 wall.  The blocks are about 30 pounds each, and easily cut with a saw.  There are still some problems to sort out, including horizontal runs of electrical and plumbing, but it’s an exciting product idea.  Oryzatech is currently looking for investors, so there’s no announced release date.

5. BrightSpark

Using wireless technology, BrightSpark from Econetix is a plug-and-play home energy management system.  There will be a DIY starter kit for $250 that includes a B&W touchscreen (which also serves as a programmable thermostat), 3 light sockets, a wall outlet, and a 6 outlet power strip, and a larger Retrofit / New Construction Kit and color touchscreen.  The system gives you a dashboard showing energy consumption of individual fixtures, but can also be programmed to quickly put the entire house into “sleep mode.”  The company is in talks with PG&E to get access to smart meters as those are rolled out, so BrightSpark can also show real-time energy usage of the entire house.

6. EcoBatts

Not from the Innovation Pipeline, and only new in the U.S., EcoBatts is an interesting “new” product nonetheless.  As with other fiberglass insulation, it’s made ultimately from sand, but Knauf also uses recycled glass.  Its bio-based ECOSE binder also means there’s no phenol or formaldehyde.  The result is a batt that costs the same as other traditional fiberglass batts, but is GreenGuard certified for Children & Schools.

Photo credits: Gene Anderson.