The Weekly Carboholic: Green construction does not always mean "natural"

Posted on November 19, 2008



The R-value for a 2×4 pine wall stud in a wood frame constructed residence is about 4.38. The R-value for the fiberglass batt insulation that fills the cavity between the wall studs is between 11 and 15 (source). In an exterior wall that’s constructed with studs at 16 inches on center, that means that roughly 9% of the wall has an R value that’s less than half that of the insulation. It also illustrates why green buildings are not necessarily going to be constructed of all-natural, renewable materials. Sometimes the natural materials just aren’t as good.

While the American Chemical Society Chemical and Engineering News story linked above occasionally reads like a product brochure for Dow Chemical, BASF, 3M, et al, it provides some interesting information. The article proposes that buildings that last, need minimal maintenance, are energy efficient are the greenest buildings, especially with the inclusion of high tech products manufactured using green chemistry. Obviously, if you’re going to lose significant heat through the natural pine wall studs, then an argument could be made that the natural solution (softwood studs) isn’t necessarily “green.” But maybe replacing standard gypsum wallboard and external plywood siding with structural polyurethane panels is enough to compensate for the losses due to the studs. The trick with polyurethane foam panels, according to the article, is to find some that are expanded with air instead of fluorocarbons (which are powerful greenhouse gases and can leak from the panels over time).

The article describes a number of other interesting new technologies. Small wax capsules embedded in flooring and wall panels are being used to help reduce temperature variability in offices. As the building heats up during, the wax eventually starts to melt, absorbing a significant energy as it changes phase from solid to liquid. In the evenings, the wax capsules gradually release their energy back into the building as the wax re-solidifies. These phase changes reduce the amount of cooling (and heating) that the building’s HVAC system must produce. And a form of voltage-controlled window shading that is coated on the window glass itself enables a simple controller to adjust how much light penetrates the building’s interior, from nearly all of the sunlight to as little as 2%.

But while it’s hardly as “sexy” as new green buildings, the most important green building is not the new home made with structural polyurethane panels, wax capsule wallboard, and so on – it’s the building being retrofit from an energy waster to a highly energy efficient structure. As the article points out, little of the building is thrown away and a building that used to throw away energy doesn’t any more.

Perhaps the most important point made in the entire CEN article was made by green homeowner Jean Merritt in the second paragraph: “There was a lot of disagreement within the community about what is green. You have to sift through people’s motivation. Are they just trying to sell you a product?”

Given all the times that specific chemical companies and their products were mentioned in this article, that’s a reasonable question to ask of Chemical and Engineering News too.


Skeptic Magazine’s blog debunks Global Warming Petition Project
Michael Shermer founded and publishes Skeptic Magazine, has written 11 books, and writes a column for Scientific American, the magazine where I first encountered his work. Skeptic also publishes an online enewsletter known as eSkeptic, and on November 12, eSkeptic ran a guest post by Gary J. Whittenberger Ph.D. titled Misleading by Petition – Just What is the Consensus on Global Warming?. In it, Whittenberger disassembles one of the memes that came out earlier this year from the denier camp, namely that an online petition signed by over 30,000 so-called scientists could possibly disrupt the claim that the experts nearly all agree that climate disruption is largely driven by human emissions of carbon dioxide (CO2).

The petition in question is known as the Global Warming Petition Project, and it is organized by the Oregon Institute of Science and Medicine, a group out of rural Oregon that has ties to global warming denier groups and, through its support of home schooling, a number of conservative Christian and Catholic groups as well. The website claims that the petition “signed by over 31,000 American scientists.” But what Whittenberger found is that this is hardly the case. As he says in the eSkeptic piece:

[OISM principle Arthur Robinson] even seems to think that persons with Bachelors degrees in mathematics and engineering are relevant and qualified experts on the issue. This seems to make about as much sense as considering electricians to be experts on plumbing because they have certificates from trade school just as plumbers do.

As someone who has spent some time investigating the OISM myself, I have to agree with Whittenberger’s conclusions – that the OISM’s petition “solicited the opinions of the wrong group of people in the wrong way and drawn the wrong conclusions”. Similarly, any climate disruption skeptic or denier who relies on this petition to prove their point is relying on the wrong source.

h/t: Mike “Random” Pecaut


UNESCO’s aquifer map a guide to future water conflict?
Water is a dwindling resource. Glaciers are melting. Droughts are becoming more common and harsher. And an increasing global population is stressing what water remains more and more. And so water conflicts are expected to increase in both frequency and severity. A few weeks ago, UNESCO released a global map that shows all the major aquifers and sources of groundwater and how they intersect international borders. The purpose for this map, as reported by New Scientist, is to push the international community to develop a treaty regarding how water resources are shared across national borders.

The problem is this – if one nation pumps water out of an aquifer (especially from a fossil aquifer that isn’t being refilled by seasonal rains), then that nation’s neighbors have less water, and that could lead to armed conflict. This is essentially the problem that the Colorado River Compact mostly solved between the eight states that use the Colorado River in the U.S. Southwest in the 1930s, but writ large with actual warfare as a possible outcome. And as with the eight parties to the Colorado River Compact, the more nations that are involved in drawing from a single aquifer, the more difficult multi-lateral treaties over that water will be, and the more important an international, UN-developed global treaty becomes. And it appears from a detailed look at the map that there are significant portions of Africa, Europe, and Asia where ten or more nations could all be drawing from a single aquifer, increasing the likelihood of conflict.

This map is relatively general, and the article says that a more detailed map of the world’s aquifers will be released in spring, 2009. But the map is good enough to illustrate something else – merely agreeing on how aquifer water will be extracted won’t be enough. Without a significant amount of scientific knowledge of how the aquifers are recharged, and an understanding of how recharging is expected to change in the future as a result of anthropogenic climate disruption, international laws may not be enough to prevent water conflicts among so many interested parties drawing on a common resource. If your people are dying of starvation because you’re not allowed to pump enough water out of the ground to grow your crops, you’ll almost certainly ignore the “agreement” that limits your pumping. And if/when that happens, all the agreements in the world won’t prevent open warfare.

h/t: Lex


New data on charcoal in soil raises carbon questions
Soil researchers from the U.S. and Australia have published new data that raises questions about how much carbon soils can sequester, and how much carbon is released into the atmosphere when land use changes. According to the ABC Science article linked above, the authors of the paper suggest that climate models are underestimating the amount of carbon that is sequestered in soil.

This new data needs to be understood in case it does, as Dr. Evelyn Krull suggests, make climate disruption “look worse than it actually would be”. I look forward to reading more about this new data, and how it affects the climate model predictions. More accurate models are always a good thing.


Wave and tidal energy growing pains
In the second Weekly Carboholic, I introduced readers to Finavera Renewables, a company who was placing a prototype wave power generation bouy off the coast of the Olympic Peninsula for a trial run on how wave energy could be tapped along the Pacific coast. The Seattle Times ran an article last week that provides an update on Finavera’s pilot program as well as a number of other wave and tidal energy programs in the Pacific Northwest.

Finavera remains the only company who actually has an approved permit for an ocean pilot program, but they’re not alone in being interested in the potential for ocean-based energy. Another company is looking at large emplacements of water turbines to take advantage of the significant tidal flow through Admiralty Inlet, the main water inlet into Puget Sound from the Strait of Juan de Fuca. But at this point no-one has put any generation buoys or turbines into the water. Concerns about fishing grounds, a marine sanctuary, and the effect of electric cables on marine life have held up many of the dozens of programs the article claims are in some stage of development.

It’s probably only a matter of time before some project developer actually puts something in the water, but it’s good to see that environmental concerns aren’t being pushed aside in favor of energy – and that the economics of ocean energy (currently estimated at about 20 cents per kWh, as compared to 4 cents from wind turbines) isn’t being ignored in favor of the latest energy fad.


Update on hybrid vehicle technology
Today’s Green, Inc. blog at the NYTimes has two articles that talk about new developments in hybrid vehicle technology. The first is about the use of ultracapacitors as a temporary energy storage system in order to lengthen the life of hybrid batteries and the second is about making hybrid heavy trucks.

Batteries don’t like sudden surges of energy, either coming into the battery while charging or going out of battery while discharging. Large swings in current tend to degrade the battery life as the current heats up the battery and, in extreme cases, could cause the battery to over heat and burst into flame. In standard electronic systems, this energy flow problem is handled with storage devices called capacitors. Capacitors store energy in an electric field and provide the high frequency currents that modern electronics need, leaving batteries to provide the more-or-less constant base current that feeds the overall power consumption of the electronics. Capacitors that are large enough to provide the same basic functionality for a hybrid car as it accelerates or brakes hard (with regenerative braking) have been extremely rare and expensive due to their size and energy storage requirements. But now AFS Trinity Power may have developed a high energy density, high voltage, and relatively inexpensive ultracapacitor to do the job. Green Inc reports that when an independent lab tested the capacitor/battery combination and compared it to a battery-only option, the battery lifetime increased by 7.6x, from 500 cycles to 3800 cycles. In terms of a car lifetime, that’s an increase from less than 2 years between battery replacements to over 12 years.

Large trucks cannot be propelled by electricity alone, but a large truck’s efficiency can be improved by the addition of a hybrid system, according to the second Green Inc article. The same basic technology that is currently in use in buses and delivery trucks is being redeveloped for use in large trucks such as semis and utility vehicles. While I don’t know exactly how it works, one of the main advantages that electric motors have over combustion engines is in low-speed torque, so I can easily imagine that a hybrid system could be utilized to reduce the overall horsepower required for an equivalently sized vehicle as the electric motor aids the diesel engine at low speeds or as the vehicle is moving over steep or rough terrain.

And let’s not forget – there have been “hybrid” diesel-electric train locomotives since they were invented – in 1917. Cars and trucks are just a little behind the curve.

Image credits:
Heartland Builders, LLC
WIRED Underwire blog

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