Thermal Bridges, Passive Houses in the UK, and Spray Foam

On the fence
Chain link fence (get it?) - (image by James Jordan, CC 2.0 licensed)

As I’ve been surfing green building sites and articles over the last week, I ran across these interesting items. I hope you find them useful.

Thermal bridging occurs wherever assembly components with low R-values relative to surrounding materials span from the inside to the outside of a building assembly.

  • What’s the UK doing about energy efficient building, you ask? They have a zero net energy homes initiative, where all new homes in the UK are supposed to be zero net energy by 2016. Probably not going to happen on schedule, according to an article from NewStart magazine, described on the Barefoot & Gilles site. (H/T to Sue Butcher for the link, via Twitter.)

Flaws in the government’s zero-carbon vision have forced ministers back to the drawing board. Is there a realistic way forward?

One wall design that is sure to become more popular utilizes 2×4 studs, 2″ foam board as a thermal break, 7/16 OSB or other structural sheeting using 3.5″ screws for fasteners. Then the 2×4 stud cavities are sprayed with 2″ of closed cell foam. The total wall thickness ends up to be 6-9/16″, standard for window and door jambs. The R-Value of this quiet and comfortable energy wall is 24!

There are still questions about the GHG impact of making and spraying the foam, although The Foam Man also points out that all insulation techniques involve tradeoffs, and some spray foams have a high quantity of soy-based content, which lessens their footprint vs. petrochemical-based foams.

Let me know your thoughts in the comments.

High Tech Innovations Vs. Low Tech

Bamboo thicket
Bamboo - Fast Growing CO2 Sequestration (Image by Joi, CC 2.0 licensed)

I read Technology Review for the latest innovations and breakthroughs in fuel cell technology, transparent solar cells, exotic new batteries and things like that. But there are tons of much lower tech innovations happening all the time. I happened to meet a guy the other night who’s working on a new startup related to building construction.

They’ve developed a new structural component – basically a really strong sheet of plywood – and some connectors, and they think based on their current testing results that they can build houses for 70% of the cost of regular 2×4 stud construction, much faster. They have almost no waste on the job site, and the waste in their factory is all reused. The system is fairly green as well – the feedstock for their plywood is bamboo, one of the best plants for taking up CO2 – and they use non-toxic glues and finishes. And their construction method will work very well for [intlink id=”393″ type=”post”]passive houses[/intlink] as [intlink id=”368″ type=”post” target=”_blank”]discussed elsewhere[/intlink] on “Keeping The Lights On”.

But just like the fuel cell breakthroughs, these low-tech innovations have a tough road to travel to success. For a new building process, you have to convince builders that it’s a better alternative, and that they’ll make more money faster. You also have to certify that the houses will stand up in an earthquake, weather a big storm (or ten of them, over the years), and do all the normal things that houses do in their lifetime. You can be sure that other innovators are coming up with competitive building technologies, all trying to accomplish the same thing as you – displace the old way. So not only do you have to deal with differentiation and other competitive marketing activities, but this also means the air around the head of your prospects is blue with pitches from every direction about “revolutionizing the industry” and “lower cost, faster” and “extremely green.”

If you accomplish all those things, and get a good competitive position, then you have to actually make the new materials and all the fittings, making sure you can address the trickier needs of real houses – which are not just square walls and right angle corners.

I think the new plywood-based approach I saw can address all these issues, but my point is that just because it’s good, it’s still going to be a difficult journey. That’s true of any new innovation.

I hope to do an interview in March with the “plywood people” and put it up on the blog, and I’ll be asking them how they plan to address all these issues as they ramp up. It should be interesting to watch them and other innovations in the building trades, especially in this time of massive investment in green building and energy efficiency.

Green Shopping For DIYers

Main Street #6 (Superior Appliances)
Are They Energy Star Certified? (Image by kevindooley, CC 2.0 licensed)

In the national consciousness “green is the new black.” But what if you want to do a little work around the house – paint the kitchen, retrofit with some compact fluorescent lights, build some shelves? How much of a challenge is getting materials and advice for a green DIY or remodeling project? My friend Rich Wingerter decided to find out a few weeks ago, and went on a little shopping trip. He recounts his experience with Green Shopping on his blog The Greens.

“My take is that many green products are within hailing distance of their traditional (let’s say “polluting” cousins). If you can do a remodel with green materials and spend no more than, say, 5% above what you would have spent anyway, then you will probably profit from the results. Are there enough green options comparable in price to reasonably do a green remodel in the Silicon Valley area? To find out, I went shopping. I wanted to find out what kinds of green building materials I could buy and not blow my (theoretical) budget. “

Some highlights:

At Orchard Supply Hardware (a California chain) he asked about sustainable lumber:

I was told that they don’t sell this kind of lumber, and that they didn’t know anything about it. They directed me to the commercial desk, on the theory that maybe they had something for contractors.

At Orchard’s commercial desk he asked about green materials in general:

(Explaining, of course, that I was talking about eco-friendly products, not objects painted green). Blank stare. Crickets.

Rich fared better at Kelly Moore Paints and Lowe’s. Did Kelly-Moore have green products?

Yes, they did, and they didn’t go blank when I asked. … They had an option with a zero-VOC, as well, and gave me pricing so I could compare with the default versions. In addition, they carried Yolo Colorhouse® paints, which are zero-VOC base.

How about Lowe’s?

Joe Roche, a Regional Commercial Sales manager, understood what I was looking for. Joe was good enough to walk through part of the store with me. We went to the lumber section and looked for certified lumber. We didn’t immediately spot any, but Joe said that they often have it even if it’s not marked. He said that they had done a LEED-certified project, and they had to special order the lumber so that it all came stamped.

Rich went on to find some low-e windows and a number of Energy Star appliances at Lowes. In his post he also compares the prices of traditional and green materials, such as the paint at Kelly Moore and some of the Energy Star vs. non-Energy Star appliances.

Rich’s conclusion is:

While companies are trying to market green building materials, and in many cases probably have them in stock, the word hasn’t really filtered down to the sales floor.

Rich’s focus on this blog and on his site Green Making is green building in the San Francisco Bay Area. He is building not only an information base, but also a community site for builders and buyers who want to build green. It’s a great resource for everyone interested in green building and zero net energy homes, especially those of us in the Bay Area. I recommend taking a surf through and putting it on your bookmarks.

Have you had a “green shopping” experience? Have you been able to get good advice on a green DIY project from a local or chain hardware or building supply store? How about bad advice? Please share your stories in the comments – we’d love to hear them! – A New Biomimicry Resource and Social Networking Site

Spider silk has desirable technical properties that manmade materials cannot replicate yet
Spider silk has desirable technical properties that manmade materials cannot replicate yet

I just visited, [url corrected] a new resource and social site for people interested in understanding how nature has solved various design problems – such as energy conservation, water collection, and energy generation – and how we can use those solutions as inspiration for our own technology.

AskNature is a bio-inspiration website where innovators can learn from nature’s solutions, biologists can find a whole new audience for their research, students can be inspired through science, and collaborators from different disciplines can work together to create innovative, sustainable, bio-inspired designs.

Currently on their home page they link to articles on the three topics I mentioned above – conservation, water, and energy generation. The articles feature an overview of the topic and how nature has addressed it, an example organism that’s solved the problem in an interesting way, and then one or more technology solutions that are based on nature’s approach – often contrasted with technologies for the same problem that are not inspired by nature.

Nature solves problems for organisms using evolution, using millions of experiments over tremendous time to optimize the solution under the constraints of very low energy inputs, ability to build the solution from basic materials using a digital program (genes), and only generating waste that can be used by other organisms. When nature’s solutions can be repurposed to solve technological problems, those same constraints are additional benefits – reducing the energy required for the solution, making the process digital, and eliminating waste.

The site is a project of Janine BenyusBiomimicry Institute, a not-for-profit whose mission is to nurture and grow a global community of people who are learning from, emulating, and conserving life’s genius to create a healthier, more sustainable planet.

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A Note From The Fuel Cell Research Front

Methanol fuel cell.
Methanol fuel cell. Image via Wikipedia

I plan to do an in-depth post or series on fuel cells soon, because there is so much breakthrough work going on in this research area. Fuel cells are interesting on so many fronts – for example, they’re probably the best way to use the hydrogen generated by Daniel Nocera’s new hydrogen splitting method, announced in mid-August. And just since August, researchers have announced big improvements or cost reductions in every component of the fuel cell – membrane, catalyst, and electrodes.

This latest story from Technology Review covers a new membrane improvement for methanol fuel cells. As the article points out, methanol fuel cells have some key benefits compared to hydrogen cells, in particular that methanol is a liquid at normal temperatures, but they also have technical challenges. Paula Hammond and her team are addressing one of these:

In her lab at MIT, chemical-engineering professor Paula Hammond pinches a sliver of what looks like thick Saran wrap between tweezers. Though it appears un­remarkable, this polymer membrane can significantly increase the power output of a methanol fuel cell, which could make that technology suitable as a lighter, longer-­lasting, and more environmentally friendly alternative to batteries in consumer electronics such as cell phones and laptops.

Do you have questions about fuel cells that you’d like me to find answers to as I research my upcoming series? Let me know in the comments.

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Carbon Fiber May Not Be Necessary

Inlay with nacre tesserae; Bagdad pavilion; th...Image via Wikipedia

Looked at one way, carbon fiber composites are just our simplistic human analog of natural nano-featured composites like those that make up mussel and abalone shells. Mollusks use a “digital” process for creating their shells – a digital process controlled by a computer running DNA as its code. What if we could make composites like those little molluscs – stronger and more resilient than some random fibers jammed into some plastic?

Now researchers at the Swiss Federal Institute of Technology in Zurich, following on work done at Michigan and MIT, have created a new bio-inspired material that combines the strength of ceramics with the stretchiness of polymers. Consisting of ceramic platelets in a polymer matrix, like bricks in mortar, the material is both light and strong – approximately four times as strong as steel.

In designing the material, the researchers carefully studied the mechanical structure of nacre, the shiny layer on the inside of seashells, and tried to improve it. Nacre has platelets made of calcium carbonate arranged in layers inside a protein-based polymer. “There’s something very special about the size of these platelets,” Studart says. “Nacre uses specific platelet length and thickness to achieve the high strength and [stretchability] that you see in metals.”

This type of biomimicry is the next major frontier of materials science. Sea shell, or nacre, has long been a target for researchers in the emerging field of biomimetics – literally “copying life” – along with artificial photosynthesis for gathering sunlight as energy, multiple other materials such as spider silk, and a whole host of behaviors and capabilities that the natural world has evolved over hundreds of millions, or even billions, of years.

The combination of nature’s techniques, such as creating nacre with a digital process, and Man’s inventiveness is ushering an era of materials with amazing properties – just in time to address some of the most significant problems we’re facing, including global climate change and sustainable energy.

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