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.
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