On Saturday, I attended a Solar & Wind Expo, which was held about three stops away on light rail. At the Timonium Fair Grounds stop, there was no sign that anything was happening. I walked past the empty entrance kiosks, and saw a truck with a horse trailer backing up to the mostly empty livestock sheds. I continued past the empty cow palace, and eventually saw some balloons tied to two tiny cars in front of a nondescript concrete block building. The cars were Think City EVs. A small banner announced that the expo was inside.

I was a bit early and when I tried to pay the $10 entry fee with my debit card, one of the cashiers went to a table and pulled a cardswipe machine out of a box. She fiddled with it and asked, "Do you have any cash?" I had eight dollars, so she took that and let me in. That worked out about right because I was supposed to get two dollars off for arriving by light rail.

It wasn't a huge expo. The floor plan showed 70 booths, but there were actually about two or three dozen exhibitors. The more experienced reps quickly asked if I owned my own home because they were selling installs of solar PV, solar water panels, wind masts, geothermal and the like—and looking for live customers. They were polite when I told them I was an architect, and quietly ready to wave me on when I told them I mostly did institutional work. The fellow selling Leaf Filter gutters just handed me a card and said to call him when I needed work.

At the first booth were two fellows promoting Radiaflect Reflective Insulation which is two layers of perforated aluminum foil with a bit of recycled plastic foam between. They claim about R-5 for it, which sounded high, but its real purpose is to be a radiant barrier (RB) rather than a thermal barrier. Their demonstration box had two parabolic light bulbs shining down in each compartment, one above batt insulation, the other above the Radiaflect. Thermometers indicated that it was around forty degrees cooler beneath the radiant barrier. I asked if this was primarily for the South, but they claimed RBs would work well in colder climates, too. They even said you could place the RB beneath shingles, or behind siding. That sounded wrong, so I did some research when I got home.

According to the feds, and a few discussion boards, RBs are effective in reducing cooling load, so you might drape one between or under the roof joists if you live in a hot climate with more than 4500 cooling degree days per year, and have air cooling ductwork in the attic. But RBs sitting on top of your attic floor insulation can trap moisture, even when perforated. Also, RBs need an air space on at least one side to provide any benefit. If the RB is placed tight between sheathing and shingles, or sheathing and siding, heat will conduct through the foil. If you have the currently recommended R-38 batts of attic insulation in a cool climate, or R-49 batts in a very cool climate, an RB won't do that much for you.

Another guy was selling retrofit foam insulation. I designed a new school and a new library with open cell foam (soy-based) in the cavities and closed cell on the sheathing, but his stuff was a mix of closed and open cell intended for retrofitting poorly insulated residential cavity walls. They cut holes in the outside wall, between each stud, and pump in the foam. He had a video of it gradually flattening out the batt insulation against the inner layer of gypsum board. I've heard a lot of stories about gaps left behind, though, and not found until demolition years later.

Naturally there were a lot of companies looking to sell analysis, design and installation of PV or solar hot water panels, I only spoke to two at any length. A fellow from 21st Century Power Solutions made it clear that they were selling the best of the older, more reliable technology because the newer sort of tech was too expensive. Before I could even ask about Solyndra he said they were doing that very thin, almost painted-on PV that went under when the Chinese had forced everyone to drop their prices. I asked about the security of rooftop panels, and he wasn't aware of any special theft deterrence, that they were insured under homeowners, and that most people who bought PV were in secure neighborhoods anyway.

I also talked to a fellow from American Sentry Solar, who had a Velux solar water panel set up. It was a clean-looking unit. I asked if he had seen the Green Building Advisor claim that it was often cheaper to heat water with PV generated power than to use solar hot water systems.

In the northern half of the U.S. — and even much of the South — installing a residential solar hot water system doesn’t make any sense. It’s time to rethink traditional advice about installing a solar hot water system, because it’s now cheaper to heat water with a photovoltaic (PV) array than solar thermal collectors.

In short, unless you’re building a laundromat or college dorm, solar thermal is dead.

He hadn't, but he said that PV could be more generally useful for the money invested.

Ultra Solar and Wind Solutions had several wind displays. I first looked at the three bladed turbine, 46" in diameter, but they said that the 13 lb Air Breeze, generating 160W at 28mph of wind, was usually used to recharge batteries on sailboats or offshore platforms. Marilyn, a vertical axis, omni-directional rotor looks like a sheet dangling from three points. Marilyn models vary from 3 to 7 feet in diameter, generate 500W, 2.5kW or 3.3 kW depending on the size, require only about 6 or 7 mph in wind speed and are claimed to be avian-friendly. You can mount one above the ridge of your roof line.

The Marilyn rotor has the advantage of a larger power coefficient at the same wind speed over other rotors of similar size. Rotor movement begins at a wind speed of 2-3 m/s. At high wind speeds of more than 20 m/s, its geometrical construction provides a hydraulic self-brake limiting rotor revolutions to 150 rpm. This feature ensures protection for mechanical and electrical elements at high wind speeds without mounting brakes or electronic safety systems.

Ground Loop Heating & Air Conditioning had a display of geothermal exchange solutions featuring a three ton Water-Furnace unit and diagrams of horizontal, vertical and pond loop geothermal fields. With my small house and yard, I'd need a two ton unit and a vertical loop to a depth of maybe 100 feet, and the fellow threw out a number of maybe $30,000. I've heard quotes of $20K for larger systems, but obviously I wasn't going to get a serious price without an analysis.

Ground Loop also had a mockup of three methods of running underfloor hot water radiant heating—which is something we want to do in our house. One method requires that the fluid lines run in grooves that are routed into a plywood subfloor. Another has a few inches of gypcrete poured around plastic tubing above the subfloor or sheathing. Since we want to keep our heart pine floors, the easiest retrofit for us would be to run plastic tubing below the floor sheathing, between the floor joists.

There were about five more Think City cars inside the building, and someone was maneuvering a Leaf and two Volts into spots nearby. EuroStar Auto Gallery, a nearby dealer, was discounting them from the list price of $36,495 to about $22,500, and advertising them as costing $15,000 after the federal rebate—plus tags and title. The Think is a two seater about the same size as a Smart car, and has a skin of recycled plastic. (Later I asked a young man what he thought of the Think. He said it would be odd to own a car that felt like a trash can lid.)

Think claims 50-75 mile range in winter, 75 miles on the highway with AC and 110 miles in the city. The speedometer goes to 120 mph, but the top speed listed is 70 mph. The dealer pointed to the door edge to show off the solid construction. It wasn't nearly as tinny as the Chinese-made Electrovaya EV I rode in a few years ago, but it wasn't nearly as solid as a Leaf or Volt, either. I asked him if they were still made in Norway. He seemed surprised and said that the parts were made there, but were assembled in the US. Think! has gone bankrupt several times, and I had thought they were finally defunct, but Autoblog reports that they were bought out by a Russian investor in March 2012.

The Leaf and Volts were personal cars, immediately plugged in to extension cords. Dave Goldstein, President Emeritus of the Electric Vehicle Association of Greater DC (EVADC) owned one of the Volts, and was preaching to a retired fellow about how much he loved his Volt after 30K miles, how it was really a luxury car despite the Chevy badge, how people shouldn't be saying bad things about it on the internet, and that everyone should see Revenge of the Electric Car. He asked me what kind of car I drove and I told him, "a bike" but that I had seen the Volt at the car show, and liked it. He said he rented from Enterprise when he needed to make a long trip. We briefly discussed the idea of people sharing their personal cars with strangers, which has been an insurance nightmare for one owner, but he thought it would get worked out by the insurance companies.

I sat in on a seminar, Electric Vehicles Explained by Doron Shalvi, who is the current President of EVADC and was the owner of the Leaf recharging nearby, and Dave Goldstein. They handed out this fact sheet PDF. There wasn't a lot I hadn't heard before.

Michael Hindle, of both INDRAlogic Architecture and Chesapeake Passive House, and the Acting Chair of the Mid-Atlantic Passive House Alliance, preached fire, brimstone and climate change about the importance of designing your house to meet Passive House standards from the get-go— rather than letting some architect or builder try to "add green" too late into the design process. Despite using the word architecture in one of his company names, Hindle is not an architect; he is a Certified Passive House Consultant per the PHIUS.

Hindle didn't surprise me by pointing out that LEED was a poor measure of a building's energy efficiency, LEED basically follows ASHRAE, but he did surprise me by complaining that Watershed, last year's Solar Decathlon winner, was a climate change loser because of the long carbon payback time of the types of foam insulation they used.





Hindle showed the charts above, from Building Green, which work together—all the insulation types in the lower chart are lumped together at the bottom of the upper chart. Hence the payback years of the closed cell Sprayed Polyurethane Foam (ccSPF) and Extruded Polystyrene Foam (XPF or XPS) are far above any other sort of insulations. And these were used at Watershed.

He did however like Self-Reliance which both my wife and I thought was very successful. Apparently Hindle's wife was urging him to tone it down, but I thought his talk was a good counterbalance to the naked capitalism of the rest of the show.