Just got wind of The Archimedes ‘Liam’ turbine (oh, yeah, you knew I was going there). This thing is wicked cool looking. It’s loosely based on Archimedes screw principle, which is based on the nautilus shell, which is totally fractalian (damn, I wish I had made that word up) in my books.
The Liam F1: 1.5 meters wide, 75 Kg of quiet, energy production for your urban installation. Most turbines operate below 60% (theoretical) maximum efficiency. The Liam operates (theoretically) 80%. This is the big 1500W version. The little one is 200W, .75m across, and 32 kg.
I first saw this as a post on FB, and a friend wondered what the lifespan would have to be ’til the wee turbine paid for itself. So, being the wonk that I am, I did the napkin calculation. The article used the rated power production at 5m/s wind speed (25W) and calculated a miserable 1500kWh annual production. With a cost of $5450 US, that’s hard to justify: 1500kWh * $0.136/kWh (Nova Scotia Power) = $204/yr savings on electricity. Over 20 years, that’s $4,080 at today’s energy prices. As the average wind speed in Halifax is 15m/s, we can assume that annual production would be higher, but I don’t have algorhithm for the production curve on this beastie, so can’t say what that would be. But, given that NSP is going to continue to increase kWh price, and production would likely be higher, we can guestimate that the Liam would have to have a lifespan of 20 years to make back the price tag (big assumption: minimal maintenance).
But that’s not the #1 reason why people buy into renewables. Capital cost aside, anything that doesn’t cost you to operate yet provides you with energy is still profitable, when you put it in context of a fuel-dependent energy source, which always costs you to operate…
OK, so because I’m a complete wonk, I dove in further. There are 2 models. The one whose production is quoted in the article is the 200W unit, but the one that’s described (and shown in the picture) is the 1500W unit.
The 5m/s wind speed is at the very bottom of the performance curve, just after the turbine cuts in at 2m/s (see performance curve for the 200W unit below). It’s rated at 12m/s and our average wind speed is 15m/s, but let’s say we get 10m/s average in a less than optimum installation. It’s rated to generate 125W at that wind speed (vs 25W at 5m/s). That is wildly better production…just over 7,500 kWh annual production. That’s an annual saving of $1,020 at today’s NSP rates. Now we’re talking. Even accounting for cut-out at +25m/s for 20% of the year, potential production is over 6,000 kWh ($816 in savings). And on top of that, the Archimedes comes in perfect whirligig colours. Very appealing.
Deep Energy Retrofits , Energy Efficient Stuff , Indoor Air Quality , Stuff that makes me crazy
Damp basement season. It’s coming
What are you going to do about it? Hopefully not install an exhaust only system to pull more humid air into your humid basement.
Don’t. Do. It.
I’ve been discouraging these systems forever, here in Nova Scotia. They don’t reduce humidity levels in basements, but that’s what the marketing infers. What they do is exhaust the humid air from the basement while bringing in humid air from the outside. There is no way to reduce relative humidity levels and stop condensation without a) increasing the ambient air temperature so that it can carry more moisture while at the same time increasing the temperature of all exposed (or first condensing) surfaces or b) stripping moisture out of the ambient air (that’s what a dehumidifier does — oh, wait, that’s the market these exhaust only systems are muscling in on). In reality, the best way to deal with humid basements is to #1 Find the moisture source(s), and #2 Eliminate them. That’s the straight up, bottom line, end of story.
Moisture sources like open sumps are the problem — sealing this off before doing anything else will go a long way to reducing the moisture level in your basement or crawlspace. Note the white efflorescence on the wall — that’s salt crystals left behind from moisture migrating through the wall.
Open sumps, cracks in concrete that allow bulk water into the basement, these are pretty obvious sources. Less obvious sources include crappy drainage at the foundation, damaged or non-existent drainpipe leaders, high water tables.
Then there’s the fact that cooler surfaces cause moisture to condense out of warm, humid air. Concrete or masonry, present in most basements, are terrific first condensing surfaces. Insulating concrete and masonry can help to reduce the extent of condensation. But only if all moisture sources are dealt with so there’s trapping of more moisture in the basement…so back to #1 above.
Read this blog post by Allison Bailes at Energy Vanguard if you want more details about the pitfalls of exhaust-only systems and a fantastic in-depth explanation of why they won’t, don’t, can’t work in basements. Although he references New Orleans specifically, the physics that lead to problems with humid air and cold surfaces, along with the need to eliminate moisture sources in basements and crawlspaces are the same everywhere. The severity of the problem is related to the climate zone and the condition of the basement.
Oy vey.
We are so beyond the theoretical concept of energy-producing houses. The first generation of NZE builders are now at the dial-it-in phase. What worked, what didn’t work, how to improve performance…minimal thermal breaks, maximum thermal envelope, simplified and small mechanical systems.
Somehow I expected that an article pitched and purchased by the Smithsonian would have a little more oomph and research to it.
Just had a convo with a cold climate builder who said he has had concerns about the viability of the continuity of the air/vapour barrier created by using high-density foam in frame walls where budget dictates non-kiln-dried framing materials. Once the foam has set, and the wood starts to dry out, he has seen the studs twist and cup and significant cracks develop at the junction between the studs and the foam, and in some cases throughout the foam itself.
Although he didn’t tell me if he’d done a before/after blower door test to see what the delta, his concern was enough to make him change products. He now uses high density foam on all non-framed walls where there is no issue with movement or shrinkage and the more flexible low density foam on framed walls. He’s willing to take the hit on the lower insulation value and the additional vapour barrier requirement.
I hadn’t bumped into this issue before and wonder if there are more people who have experienced this problem, and if so, is there any documentation, and if not, do you think there should be?
edit to original post:
…apart from installation issues, I mean. Have asked a few questions of one Net Zero builder who is using high-density foam and he pointed to installation QA/QC problems with +2″ layers being sprayed, or layers are being sprayed without enough setting time between them if pulling and cracking are issues. He noted one incidence where a crap installation at the rim joists resulted in shrinkage and pulling that left gaps of 1 to 1.5 inches!
He didn’t see much of an issue with air barrier being compromised, because spray foam would be in contact with sheathing and that is stable. I have a few phone calls with other Net Zero/Low Energy builders this week that are unrelated to this topic, but I know they have experience with high density foam, so I’ll ask some more questions and report back on what I find.
According to a recent article, spring, when it finally crawls its way up the continent, will bring with it a rotten allergy season. On top of the usual pollen and mold growth, allergy sufferers will be combatting the effects of rapid changes in temperature and moisture in the air. People who have asthma will be feeling the strain now — more so as the temperatures start to ping-pong. Good news is such a cold winter likely killed off more pathogens than the last few winters. Bad news is a wet warm spring could bring higher mold spore counts. Ugh. As a person who deals with both asthma and allergies, I’m already feeling the drag on my energy and there’s a brand new 3 inch layer of snow in my neck of the woods.
Prepare for it, prepare your clients for it:
- Clean and replace all filters – furnace, HRV, A/C
- Keep mold at bay by keeping humidity levels down in the house – run the bathroom fan religiously, use a dehumidifier in damp basement areas
- Keep windows closed early in the morning – tree pollen counts are highest then
- Take your shoes off at the door to stop tracking pollen all over the house
- Pets can bring pollen into the house too – keep them off upholstered furniture and carpets/rugs, or vacuum frequently, even daily (ya, right, that’ll happen at my house…)
- An air purifier with a HEPA filter can help reduce pollen counts, these can be add-ons to ventilation systems or stand alone plug-in units for individual rooms
NREL has this cool database (that needs populating!!).
It’s called the Technology Performance Exchange. You sign in as a user or a contributor, and you have access to performance data for 17 different types of technologies, from lamp ballasts to inverters, with more categories to come.
If you’re a user, you get to search through and compare energy performance data on up to 4 different products in the category, allowing you to evaluate energy and cost savings in energy simulations. Manufacturers, third party verifiers and ‘contributing evaluators’ are allowed to populate the database.
It’s a little spotty now, in terms of data available in all categories, but my quick wheel through it showed up a very well-populated PV category: 10,780 entries. I was able to narrow the search results by system or module, then by module efficiency, rated power, cell material, total # of cells, nominal operating temp and three different performance coefficients.
Other categories, like ‘boilers’ have lots of placeholder entries (ie, brand, product line and model numbers), but have yet to be fully populated with performance data.
This is a big project, and will be über-useful when more completely populated. Spread the word!
Energy Efficient Stuff , Stuff that makes me crazy
Sir, Ma’am: Step Away From the Foil Faced Bubble Wrap!
So Martin Holladay at Green Building Advisor blogged about foil faced bubble wrap last week. Will that stuff and the ridiculous claims around it in regards to insulation ever ever ever go away?
And here’s a recent 4-pager from NAIMA
I see that Allison Bailes at Energy Vanguard also blogged about it back in 201o.
And here’s a bunch of info I posted in October 2007. Note that even then, I couldn’t believe that it was **still** something that had such bandwidth. This was posted on the old Green Building Listserve…but the whole article is available as a pdf here.
There’s a good discussion going on in the LinkedIN RESNET BPI – Energy Audit & Home Performance Group, instigated by Chris Laumer-Giddens.
One comment sums it up: “The fact that Mr. Holladay felt compelled to write this article is troublesome because it just goes to show how many unqualified, willfully ignorant contractors are out there. Not only do these people offer their clients little return on their investment, it’s likely they diverge from code and protocol, causing property damage and potentially endangering lives.”
The stuff of nightmares…litigation and very unhappy householders.
More excellent discussion has come up today, courtesy Arlene Zavocki Stewart in regards to the issue of ‘effective’ R-values. R-value, U-factor = measurement of conduction. Building envelope materials all have properties that impact heat transfer via convection and radiation as well as conduction, but mere mortals using standard issue energy modelling software acceptable to home performance, DSM, and other incentive/funding programs, can only measure or model the conduction portion with any vigor. Engineers, physicists and fans of complex spreadsheet building (she raises her hand sheepishly) may be able to do otherwise, but it doesn’t count for your client if you can’t plug it into the modelling program and have it make sense with what’s already being calculated. I have bumped into this challenge in terms of modelling thermal mass for cold climate passive solar design, but it’s the same issue: how much heat gain does a material or assembly absorb or reflect from a radiant source, and how much does that contribute to the heating or cooling regime of the building?
Arlene brings a great point to the discussion: “Codes allow ‘cutting edge’ products but our ways of measurement and communication on their features often can’t be quantified in existing conventions. Developing accurate ones is very expensive and takes years for widespread adoption, a funding line item that investors just don’t seem to account for.”
In the meantime, we have ‘snake foil’ salespeople out there, talking up effective R-values that defy all the laws of thermodynamics. I will stop short of banging my head against the wall now.
Deep Energy Retrofits , Energy Efficient Stuff , Low Energy Housing
Invited to present at WREN (World Renewable Energy Network) conference
The WREN Conference invitation came because I was invited to write a chapter in a book on Sustainable Buildings back in 2012. The book (Sustainability, Energy and Architecture: Case Studies in Realizing Green Buildings) was published last year (http://bit.ly/OXVl0k). The chapter I wrote was ‘Deep Green and Comfortable’, focussing on energy savings to be had by carrying out deep energy retrofits on existing houses.
The paper I’m writing for the conference expands somewhat on that idea, and looks at the missing part in many discussions that I’ve had in the field, with clients, renovators, lenders and other stakeholders: proving the value of deep energy retrofits. Not just for the current homeowner, but for future homeowners and for the municipality/community.
The idea came out of one particularly frustrating discussion with a potential contractor for one of my renovation clients. Note that this was a contractor who was bidding on a job that had already been specified. The client wanted to stay in the 100 year old house (location was spectacular, structure was sound, a phased deep energy retrofit was completely reasonable option). We were recapping the details of phase 1, when the contractor put down his pen and calmly told (my) client that renovating was not the right option. That the cost was likely to be more than 30% of the appraised value of the house, and therefore not a good economic decision.
Then he continued, telling (my) client that their best bet was to go out to the suburbs and buy/build new.
This, I thought, was not cool. The client’s preference — to stay in the house, and the strategy we had landed on — to phase the retrofit over 5 years, was clearly articulated, with modelled energy reductions, projected fuel costs (they were on oil, we were looking at a heat pump after major envelope work) and rough order costings showing payback and ROI. Apparently that didn’t make much of a dint in the contractor’s view, even though he had been briefed on the project and asked to review the design program and ask me any questions before the meeting.
I wondered where he pulled the 30% figure from, politely. It was a ‘rule of thumb’, he told me. I didn’t ask where his thumb had been, but I did ask him to back up the rule of thumb with some concrete information, which never came — neither did the quote.
So then I started thinking about the inherent value of established neighbourhoods with infrastructure vs the cost of greenfield development, and then I started mashing that together with the value of the resources tied up in an existing house, and the cost of retrofit vs. the cost of new construction and I got all jumped up about research and proving the case for deep energy retrofits.
For your entertainment, I’ll be blogging bits and pieces on this over the next few months…WREN conference is in August.
Blue House Energy , Energy Efficient Stuff
Special Offer on Building Science Basics, Canadian Version
The Canadian version of Blue House Energy (our sister company) Building Science Basics is $100 off the regular fee from now until the end of March. Catch a good deal and learn the fundamentals of building science at your own pace! Follow this link to the course description and shopping cart thingy.
Was rummaging around in a bunch of market research when I came across this item, from April 2013, which makes me shed many tears. Here’s the headline (go read the article if you want to cry, too):
Shelton Group Study Shows Decline in Energy-Efficient Product Purchases and Home Improvements.
I’m not weeping in angst because energy-saving habits have declined in the last three years. I’m weeping in frustration that the extent of what counts as ‘energy efficiency’ is so focused on minimal impact issues like replacing light bulbs and purchasing high-efficiency appliances, unplugging chargers and un-used appliances. Let’s look at the impact those ‘energy efficiency measures’ have on a relatively standard issue household.
I like the idea of LEDs and high-efficiency appliances and shutting off stuff you’re not using. Of course I do!!!!! So I’ve posted a bunch of info about energy efficient lighting options in the last few weeks. But those are band-aid solutions to real energy savings. It doesn’t change the amount of energy used in the house in a significant manner. It doesn’t change the financial load for the homeowner or renter. The telling part of the article is this statement: “and more than 40 percent of those who’ve actually done something are frustrated because they aren’t seeing the reduction they expected on their utility bills.”
No kidding.
In Canada, electronics and lighting account for 4 percent of overall household energy use. Appliances account for about 14 percent. Space and water heating account for 80 percent of the overall energy use. Eight-Oh. Four-fifths. Mostly All.
In the US, with a mixed bag of climate zones and space conditioning needs, appliances and lighting account for anywhere from 20 to 30 percent of the overall energy use. Space heating and cooling, and water heating accounts for 70 to 80 percent of the overall energy use. Still Mostly All, if you ask me.
What stands in the way of significant reductions in energy used for space conditioning and hot water usage? Like 50 to 90 percent reductions.
Off the top of my head…
- Not a silver bullet option offered at a big-box store
- Not easily packaged in a direct install program
- More expensive than a few cups of coffee
Simplistic, I know. The primary stumbling blocks are always cost and complexity. Low cost, simple measures are thought to be easier to accomplish. But are they? What if we took another look at measures that take the whole house into consideration and put big savings in small affordable phases? I’ll give some examples of what we’ve been looking at with our clients in the next few blog entries.
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