Recent Innovations - Residential

New materials/process’s/laws to keep buildings green

Green buildings continue to gain attention as many recent innovations have surfaced in the Residential space of which I will discuss the following:

• Solar Power
• EcoSeal
• BIPV windows from Tropiglas
• Climate Wizard Evaporative Air Conditioner
• Foamglas
• A high R-value coating with Silica Aerogel
• Drainline Heat Exchangers

Solar Power incorporated into commercial buildings

Solar power has historically been very expensive, holding back its wide use. It is about three times more expensive than electricity produced by natural gas, according to estimates by the Energy Information Administration.

But the financial barriers are falling fast. “Solar panel prices have plunged by two-thirds since 2008, making it easier for installers to market solar's financial benefits, and not simply its environmental ones” according to USA today.

“Exelon and NextEra Energy, each acquired a large California solar power farm in the early stages of development. Another utility, NRG Energy, has announced a plan with Bank of America and the real estate firm Prologis to spend $1.4 billion to install solar systems on 750 commercial rooftops” according to GTM Research.

http://clarysolarpanel.wordpress.com/2010/05/28/commercial-solar/

Cost analysis of electricity use is pertinent when commercial buildings are deciding whether or not to use solar power as a form of electricity. Many commercial buildings benefit from different types of energy upgrades including solar

The Database of State Incentives for Renewable Energy (DSIRE) www.dsireusa.org has current incentives for Texas

“For year 2013, the Federal Government is allowing companies bonus depreciation of 50% of the adjusted basis of the system. 5 Year rapid MACRS depreciation as well as the 30% Tax Credit” according to gleanpower.com

According to gleanpower “Typical rooftop installations can be done with minimal impact to business operations. Length of time from start to finish is about 4-9 weeks. This is everything from evaluation to flipping the switch.”

EcoSeal: A New System for Air Sealing Homes

Knauf EcoSeal, a sprayable caulk installed prior to cavity-fill insulation, can provide a significant reduction in air leakage.EcoSeal is an acrylic product that is applied using high-pressure paint-spraying equipment. It is installed with two 5-gallons buckets of the acrylic material which is the consistency of very thick paint. The system comes with a long, 200-foot hose, so the pump and bucket can stay in one place in the house while the work proceeds.

EcoSeal doesn’t expand as it is installed (as do foam sealants), and it takes up to day to fully cure. The cure time depends significantly on the environmental conditions — temperature, humidity, etc. The material can span up to about a 3/8-inch gap, according to Knauf, and it remains flexible.

EcoSeal was used in a building in Vermont to seal up cracks and gaps in walls and floors, here are the findings: 

When the project manager started using EcoSeal installation, the blower door was showing 950 cfm of air leakage at 50 pascals (cfm50). During the course of about four hours of work on the air sealing, that air leakage rate dropped to 640 cfm50. That’s an improvement of a third. That would significantly lower the amount of energy a building would need to heat and cool itself down !!

http://www.greenbuildingadvisor.com/blogs/dept/energy-solutions/ecoseal-new-system-air-sealing-homes

Making Healthier, Greener Foam Insulation

The downsides of foam insulation include the blowing agents used in extruded polystyrene (XPS) and most closed-cell spray polyurethane foam and the flame retardants that are added to all foam-plastic insulation to impart some level of fire resistance.

Now there’s an effort afoot to change building codes in a way that would allow manufacturers to remove the hazardous flame retardants. This is the subject of a just-published feature article in Environmental Building News 

This is a significant energy issue, because layers of foam insulation provide the easiest way to achieve the level of energy performance needed to approach net-zero-energy performance.

Nobody wants insulation materials to catch fire, so it is logical to add flame retardant (FR) chemicals to these materials if it will prevent them from catching fire. That’s the reason HBCD (hexabromocyclododecane) is added by all polystyrene insulation and TCPP (Tris (1-chloro-2-propyl) phosphate) is added to most polyisocyanurate and spray polyurethane foam insulation. These are both halogenated flame retardants—the first using bromine, the second chlorine.

The problem with these halogenated FRs is that they have significant health and environmental risks. The HBCD that is used in all polystyrene (both extruded and expanded) is being targeted for international phase-out by the Stockholm Convention on Persistent Organic Pollutants. It is highly persistent in the environment and bioaccumulative in the food chain; it is believed to cause reproductive, developmental, and neurological impacts. Less is known about the TCPP used in spray polyurethane foam and polyisocyanurate, but there is significant concern in the health and environmental community.

Building codes require that foam-plastic insulation meet a very specific flammability standards. But building codes also require—for most applications—that foam insulation has to be separated from living space by thermal barriers, such as gypsum drywall.

The efficacy of flame retardants compared with thermal barriers

Combustion studies that were done in the 1970s showed that if the insulation is not protected with a thermal barrier, there is no correlation between the presence of FR and the extent of the resultant fire. Thus, the inclusion of a FR does not seem to appreciably increase the fire resistance of foam insulation, according to a peer-reviewed technical paper recently published in the journalBuilding Research and Information.

However, thermal barriers like half-inch drywall work extremely well at containing fires. The 15-minute protection provided by half-inch drywall gives occupants time to escape a fire. In other words, of the two measures used to impart fire safety to a building assembly (FRs in foam insulation and thermal barriers) almost all of the fire safety benefit is provided by the thermal barrier.

BIPV windows from Tropiglas

Tropiglas was displaying its building-integrated photovoltaic (BIPV) window technology, which uses a polymer layer sandwiched between two panes of glass. When sunlight passes through the first pane, it is captured by the inner layer and directed to the edge of the glass (similar to how optical fibers work), where standard monocrystalline PV cells convert the light to electricity.

The glass is free of visible cells, unlike most current BIPV glazing options, whose cells block part of the view. But the efficiency is only around 4% (35 watts/m², 80% transparency, 90% IR blocking,SHGC< 0.41). The company claims the manufacturing process is similar to that of low-e coatings, so it shouldn’t cost much more to manufacture, but of course, you still have to contend with the other PV components and wiring.

Tropiglas is still looking for glazing partners but expects to have product on the market in 2013.

     Climate Wizard Evaporative Air Conditioner

Climate Wizard (see it in GreenSpec here), from the Australian company Seeley International and distributed in the U.S. by L&H Airco, is a refrigerant-free indirect evaporative air conditioner similar to the Coolerado we list in GreenSpec and reviewed for EBN back in 2008.

The Climate Wizard uses fans with energy-efficient electronically commutated motors (ECM) to move air through a heat exchanger that contains both wet and dry channels.

Climate Wizard is a refrigerant-free evaporative air conditioner that provides cool, dry, fresh air along with energy savings.Heat is transferred across the membrane from the dry to the moist channel, where it is vented into the atmosphere.

The cool, dry, fresh air then passes into the building to provide cooling. Climate Wizard uses 6.6 gallons of water an hour for the 10 kW model (about 2.8 tons cooling); a 15 kW (4.3 tons) version is also available.

Climate Wizard is used primarily in commercial applications.

Foamglas

Foamglas is a cellular glass insulation material. Foamglas is water-resistant so can be used below-grade; it has high compressive strength so can be used beneath a concrete slab floor; it insulates very well (R-5 per inch); and it’s inexpensive. These properties make XPS the nearly universal choice for sub-slab and exterior foundation insulation today.

Extruded polystyrene is what is in the mainstream as of today. Relative to performance, extruded polystyrene (XPS) is a great product. It is water-resistant so can be used below-grade; it has high compressive strength so can be used beneath a concrete slab floor; it insulates very well (R-5 per inch); and it’s inexpensive.

These properties make XPS the nearly universal choice for sub-slab and exterior foundation insulation today. But along with these benefits are some significant downsides. All XPS today (as well as expanded polystyrene, EPS) is made with the brominated flame retardant HBCD that has recently been added to the Stockholm list of Persistent Organic Pollutants (POPs) and is being banned in much of the world. HBCD provides some level of fire protection, though some studies suggest that its benefits are greatly exaggerated—and that that protection, if real, is irrelevant below grade. In addition, XPS is currently made with the blowing agent HFC-134a, which is a potent greenhouse gas that contributes to global warming. And some of the petrochemical-derived raw materials, including benzene and styrene monomer, are carcinogenic—though once converted into polystyrene, that carcinogenicity is not present.

Foamglas is a cellular glass, rigid boardstock insulation material. It has high compressive strength, excellent moisture resistance, and tremendous fire resistance without the use of flame retardants. It is moderately well-insulating at R-3.4 per inch (32% lower than XPS), and it’s made without environmentally damaging blowing agents. It is also about the only insulation material that is totally impervious to wood-boring insects—a useful property for below-grade applications—particularly in a warming planet with termites extending their ranges north.

Foamglas has actually been around a long time—since Pittsburgh Corning introduced it in the 1930s—but it is used primarily for high-temperature industrial applications, such as insulating steam pipes and furnaces. It’s use as an insulation material for buildings remains very uncommon, though this use is increasing in Europe.

Even though Foamglas is significantly more expensive than XPS and its per-inch insulating value is lower, the environmental and health benefits made me want to try it out on our own home.

A high-R-value coating with Silica Aerogel

Silica aerogel is a bizarre material. Aerogel is the lowest-density solid known. It transmits light and insulates extremely well, owing to its molecular structure. For the past decade, the Cabot Corporation has produced silica aerogel granules under the brand name Lumira (previously Nanogel) that are used in daylighting panels that provide diffused light even while offering remarkably high insulating value (about R-20 in a 2-1/2" panel), and the material is also incorporated into a felt-like mat that can be used in roofing fabrics. Find Lumira in GreenSpechere.

At Greenbuild the company introduced a new formulation of silica aerogel.  Enova, which can be added to paint to provide a thin, insulating coating.  A very effective demonstration in the booth used a piece of aluminum that was half painted with this 2 mm-thick coating and half uncoated with a refrigerated space behind.  You could feel dramatic difference in temperature since the aerogel coating significantly reduced heat flow through the material.  A key benefit will be preventing condensation.

http://www.americanbuildingtechnologies.com/weatherization/insulation/nanogel-higest-R-Value-insulation/

Drainline Heat Exchangers

This simple system for recovering heat from wastewater makes a lot of sense—especially for families and commercial buildings that produce a lot of hot water.

A special section of copper drainpipe is installed beneath a shower (typically the largest hot water use in a home) or other hot wastewater source. This section of drainpipe has smaller-diameter copper piping wrapped tightly around it. The cold-water supply pipe leading into the water heater is diverted so that it flows through the small-diameter copper pipe.

When hot water is being pulled from the water heater to supply the shower, the water going into the water heater is preheated by the wastewater going down the shower drain. If it’s a tankless—rather than storage—water heater, the incoming water temperature will be higher, so less energy will be required to get it up to the needed delivery temperature—thus saving energy (though the tankless water heater has to be thermostatically controlled and, thus, able to deal with inlet water of varying temperature.

The man who invented the drainwater heater exchanger, Carmine Vasile, called the product a GFX, for “gravity-film exchange,” recognizing that water going down a vertical pipe forms a film that clings to the inner walls of the pipe where the heat can effectively be transferred through the copper to the supply water.

No moving parts, nothing to wear out

The beauty of drainline heat exchangers is that there are no moving parts, nothing the wear out, and nothing to get clogged. Only fresh water goes through the small-diameter supply pipes; any hair or other materials pass through a standard, smooth drain pipe. 

Maximizing recovery efficiency

According to an article in Environmental Building News, heat recovery efficiency can be as high as 60%—which can effectively double the water heating efficiency. Just how much benefit a drainline heat exchanger will provide will depend on usage patterns and how the plumbing in a house is configured.

 http://www2.buildinggreen.com/blogs/drainline-heat-exchangers

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