[Greenbuilding] Collective wisdom over the last quarter century of renewable energy/e-efficiency?

[wmdorsett at sbcglobal.net]

   We are writing a grant to repair and update a passive solar greenhouse that was funded by DOE as a demonstration project twenty five years ago. It has a large beadwall, earth tubes, large Kalwall water tubes and stone thermal mass, active water heat storage and a defunct solar water heater, and very good insulation. All things considered, it has performed quite well. The characteristic common to several of the failed components is the lack of convenience. A Clevis Maltrum composting toilet required too much maintenance and so was the first to go. Thermal shutters were forgotten to close, even the beadwall was neglected much of the time. As interest and the requisite skills dispersed, new people didn't know to add glycerin to the bead tank to get rid of the static cling between beads. So one of the things we've learned is that unless it is convenient as in putting the beadwall on a timer, effort overcomes people's interest. The insulating panels remain under the bed.

   The grant will update to today's technology. however aside from the water heater and maintenance, the structure is largely current. Thermal mass and good insulation matched to the amount of glazing is still as good as twenty years ago. After all we're still pointing to the cliff dwellings four hundred years later. 

   So what major advances have we made in the past twenty years? Can you name the last twenty years' top five innovations in building related renewable energy and how about another five in energy efficiency? I'll throw in some crumbs of my own:

PV balance of system hardware has clearly leaped forward with sine wave inverters instead of square or semi-square ware, maximum power tracking charge controllers, largely dispensing with batteries for grid connection. The modules are still fairly evenly divided between multi-crystalline and thin film. Poly junction amorphous is only ten or fifteen years old. I think the jury is still out on PV shingles due to cost and labor. The industry seems to be moving away from 12V modules to much higher voltages more adaptable to grid connections than stand-alone systems. I am afraid this focuses heavily on the needs of industrial countries and neglects technical advances needed for developing ones to leap frog past our aging grid.

Solar water heaters? I think in much of the US, it is still hard to beat the simplicity of batch water heaters...tank in a box such as Cornel's. They fail from corrosion inside so a lifetime stainless tank and fittings would be a huge impovement. 

Load efficiency has undeniably improved. Refrigerators, microwave ovens and CFL lighting with electronic ballast's, variable speed and DC motors, washers and dryers (though none approach a clothes line). Remote pumping hasn't changed all that much in twenty years.  The Italian pump which seemed a lot like Grundfos' SQ Flex was a maintenance head ache. We're still choosing between high voltage/high powered centrifugal and small diaphragm pumps. The point of failure is the diaphragm for which the best material to my knowledge is Santaprene. I suspect the SQ Flex will suffer similar wear points. 
   
The selective surface metal roof coatings mentioned by Alison Kinn and Eva Wong, and the new low-E glazing films which exclude solar heat gain but allow high visible light transmission are major advances. 

   As they've called it for two decades, solid smoke, aerogel has been suggested for insulating between the panes of double pane glass for an R10/inch. I am concerned that the gel is fragile enough that nearby passing traffic would vibrate the gel into dust. Are there any manufacturers who actually are offering windows with aerogel? Are there other glazing systems which perform dramatically better than triple and quad glazing with argon and non-conducting edge spacers? From my experience the frame material and weather stripping is a weak point. Even clad windows dryrot when the weather stripping fails with drying and flexing, so I think the maintenance free-est choices are fiberglass and foam filled vinyl frames. If it is used for 7000 hours of flexing in pumps Santaprene ought to be the best lasting weather stripping. Loewen is perhaps only one window manufacturer which uses it. 

Our understanding of moisture transmission in walls and ceiling structures has dramatically changed. no longer are we wrapping interiors with visqueen. Blown in insulation, cellulose and perhaps fiberglass BIBS


What wisdom has all your collective experience given us over the last twenty five years?