Totally Tubular

You see them everywhere in China, ungainly water tanks jutting above the roof lines of homes and apartment buildings, the mark of a developing country where indoor plumbing has been slow to arrive. Or at least this is what I initially thought.

But solar hot water collectors, or evacuated-tube collectors in particular, are a fabulous solution to rising electricity costs, where hot water is responsible for as much as 30% of a domestic utility bill.

You see this thermosiphon version (above) of ET solar all over China, but particularly around Shanghai and south to Shenzhen along coastal China. There must be hundreds of ET solar hot water factories making these units, serving the large demand within China and now for the export market.

I took a factory tour once of a joint venture company, Sino-British, that made a basic unit for approximately the equivalent of $900. It couldn’t possibly supply enough hot water for an American family of four in a temperate climate like that in Shanghai. But in a clime as hot and with as much insolation as south Florida it probably could.

((For scientific verification of average solar resource by location go to: http://www.nrel.gov/rrdc/pvwatts/))

Flat-plate collectors are more familiar in south Florida for their simplicity and lower cost as a pool heating source. But evacuated-tube collectors, thought to be best for mild climates, are going to eat into market share as they get out into the marketplace, even though they cost more.

How ET technology works is simple: those long tubes are double-glazed glass (tube within a tube), at the very center of which is a black absorber plate and tube which carries a heat-transfer fluid into a manifold at the top. The insulation provided by a vacuum between the two tubes gives ET a greater efficiency curve, meaning that the difference between inlet temperature and ambient temperature causes less heat loss and thus greater efficiency in the ET over the flat-plate.

The ET may be easier to install than a flat-plate, all things being equal, because the tubes can be inserted last. And especially good for south Florida, they can be removed before an advancing hurricane.

The biggest problem I foresee with ET is the residential aesthetics: ET systems are ugly, no less in the U.S. than in China. All the better if the water tank can be burrowed within the envelope of the house, but shiny tubes are still not as pleasing to the eye as the dark sheen of a plate.

Countering Green Conventional Wisdom

A great piece in Foreign Policy, a favorite journal of mine, confronts head-on several common assumptions about renewable energy that hold greater sway over policy debate than they should.

While a couple of the 7 myths are straw men intended to frame the discussion, several others are so spot on it's hard to believe anybody promoting these orthodoxies about renewables is still getting a pass.

http://www.npr.org/templates/story/story.php?storyId=112327040

For example, the myth that we should be doing everything possible to promote alternative energy is ridiculous on its face, because panicky and ill-thought-out responses aggravate the disease they purport to cure.

Case in point is the biofuels movement, which Congress rammed through under pressure from the farm lobby. As if the pervasiveness of subsidized corn in our food diets isn't enough, we are pressing corn into action to power our fleets. Not to say that cleaner fuels aren't desirable, but there are probably cheaper and more efficient feedstocks (switchgrass from Montana, sugar cane from Brazil) than corn.

Add to this the fact that a lot of petroleum (fertilizers, tractors) is consumed harvesting corn, to say nothing of the carbon emissions resulting from such effort.

Another related myth is that biofuel mandates will evolve and we'll get better resolving these contradictions in the future. The author quite correctly points out that so long as agriculture-for-fuel's footprint grows, displacing valuable forest cover, we are hardly out of the woods, and may in fact be increasing emissions over the long term and doing greater harm.

The logic of all this may be too compelling for even the most powerful vested interests in biomass and biofuels to stop: that it may be wiser to mandate lower fossil fuel consumption and carbon emissions through aggressive auto fuel economy standards, carbon sequestration, and other energy efficiency measures than ravage the world's forests.

"Deforestation accounts for 20 percent of global emissions, so unless the world can eliminate emissions from all other sources--cars, coal, factories, cows--it needs to back off forests."

Bottom line, says the author, and most non-PC, is that we'll still need gas and oil and coal for some time to come, we just need to use a lot less of it. It seems unorthodox, even today, to suggest that Jimmy Carter was right, we need to change our behavior, and that while energy efficiency can do great things, conservation may be even better.

So, turn down the thermostat, put on a sweater, car pool to work, or better yet, ride a bicycle.

Breaking News: BEETLE INVADES NEW JERSEY!

It is not the most high-profile of environmental causes, but eradication of non-native plants gets some play in New Jersey ecology circles these days as a noxious weed is threatening to take over the Garden State's lower third.

With help of an imported Chinese beetle called Rhinoncomimus latipes, state agriculture officials are taking on Mile-a-minute, an appropriately named herbaceous nuisance that is literally strangling Christmas tree seedlings and other plants with economic value to the state.

This plant is a threat because it grows an astonishing six inches a day and spreads unchecked, first through railroad and power line easements, then along highways and into farm lands.

It's not quite as epic a struggle as locusts and Pharoahs, but the non-native weevils are loosed upon the non-native weed, pitting a Chinese bug against a Japanese import. Mile-a-minute was brought to nurseries from Japan sometime last century and, like Godzilla, it busted out to terrorize the local populace. Alright, so I exaggerate just a little.

The research station housing the weevils is the Phillip Alampi Beneficial Insect Rearing Laboratory, built in 1985 for biological pest control. It seems herbicides after Rachel Carson are as popular as kool aid after Jim Jones.

I met one of the young researchers at a gathering of environmentalists and was fascinated to learn that Chinese entomologists had collaborated insofar as identifying the species and where it might be gotten in the country of origin. I still don't know from which provinces the beetle hails from in China.

But it was a match made in heaven (or hell in the case of the plant): that is, the Chinese weevil thrives on Mile-a-minute and not a single other plant species in New Jersey. Once it devours all the noxious MAM in its habitat it effectively dies off.