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Conserving the differences

As I write these words, smoke is rising from burning oil storage tanks at Ras Lanuf, one of Libya’s main oil ports and a battle zone in what Western media are still trying not to admit has long since crossed the line into civil war. The price of Brent crude oil, the international benchmark grade, is currently on the upside of US$115 a barrel, ticking nervously upwards whenever anybody in the industrial world remembers that this Friday has been announced on anonymous websites as a day for mass protest in Saudi Arabia. What was that old joke about living in interesting times?

I suppose it’s probably unnecessary to point out that this is the sort of thing that happens when a civilization runs up against the limits of its resource base. About 1.3 million barrels of oil per day that usually flow into the global economy from Libyan fields is shut in at the moment, due to the fighting; that sounds like a lot, and of course in objective terms it is, but it’s less than 2% of the world’s total daily oil production. Not that long ago, a 1.3 million barrel a day shortfall would have been a minor issue for the world’s economies, easily covered the moment one of the world’s other oil-producing nations decides to cash in by turning open the tap a bit further. This time, it’s driving a drastic price spike and sending gaggles of panicked US congresscritters to the nearest microphone in order to insist that the US ought to draw down its, ahem, Strategic Petroleum Reserve.

The difference, of course, is that since 2004 global oil production has flatlined but demand has continued to grow, and at this point there’s very little slack left. You can draw your own conclusions about what’s likely to happen when global oil production begins to decline, as it will within the current decade. It’s not likely to be pretty.

That, again, brings us back to the need to use energy less extravagantly than we’ve been encouraged to do by the rock-bottom prices and purblind optimism of the last thirty years or so. It’s useful to keep the wider context in mind, because this week we’re going to talk about one of those cheap, simple, grubby tasks that most people know they ought to have done a long time ago, and a surprisingly large number of people never get around to doing: wrapping your pipes and ducts.

Here’s how it works. Most American homes have a furnace and a water heater stashed away somewhere out of sight. Hot water from the water heater flows through pipes to wherever it’s wanted, which may be on the far end of the house; depending on your heating system, there are most likely either pipes taking hot water from a boiler to radiators, or ducts taking hot air from the furnace to registers, and either way they’re going all through the house. That’s straightforward enough.

Look at it from the point of view of thermodynamics, though, and it’s a little less simple. You’re trying to get a certain amount of heat from the water heater to the taps, and from the furnace to the rooms you want to keep warm in winter. To do it, you’re sending a heated fluid, either water or air, through pipes or ducts which, for a variety of reasons, are normally made of substances that transfer heat very readily. If there’s a heat differential between the fluid inside the pipes and the air outside them, in other words, you lose heat.

The standard approach to dealing with this in conventional American housing is to get the working fluid of your system hot enough so that, even after it flows through those cold metal pipes or ducts and gets to wherever it’s going, you still get enough heat out the business end. That’s the way Americans have learned to think about energy: the solution to every problem is to crank up the thermostat and burn more fuel. That might be a plausible approach if you’ve got so much concentrated energy sources that you don’t know what to do with them all, and there was admittedly a time when that was more or less the case here in America, but nowadays? Hardly.

Nowadays, in a world where energy is no longer cheap and abundant, and is going to get a lot less cheap and abundant over the decades and centuries to come, we need to learn a new way to think about energy. Recognizing that energy is scarce and expensive is a good start, but it’s possible to go a bit further than that, and recognize that what you need to do if you want to work with energy – especially scarce, expensive energy – is to conserve differences in energy concentration.

Your hot water pipes make a good example of this principle. The water that flows out of your water heater into your pipes is at 120° F, let’s say. The air in the basement where your water heater is located is around 50° F. The second law of thermodynamics says that heat always flows from a hotter substance (i.e., a higher concentration of heat) to a cooler substance (i.e., a lower concentration), and the rate of flow depends partly on how easily the materials in question transmit heat, and partly on the temperature differential between the two substances. In other words, when hot water flows through a cold basement, what you tend to get is lukewarm water and a basement that isn’t quite so chilly. You haven’t conserved the difference between the two, and the result is a chilly shower.

Insulation is one of the standard ways to conserve the difference. Wrap your hot water pipes in a good thick layer of insulation, and the heat in your hot water has a much harder time moving from the water to the air in your basement. That means, of course, that you get your hot shower. It also means that you can get the same temperature in the water coming out of the tap while using a smaller amount of energy to heat the water in the first place. That’s valuable when it’s a matter of decreasing the amount of fossil fuels you use, as it is for most people nowadays; it’s absolutely crucial once we’re talking about renewable heat sources.

As I’ve mentioned here repeatedly, one major difference between the energy you get from fossil fuels and the energy you get from renewable resources is concentration. Lukewarm sunlight simply doesn’t pack as much punch as burning coal. You can heat water with sunlight, but the process is never going to be as efficient as heating water with fossil fuels or electricity because the heat you get from sunlight is much more diffuse. Of course there’s the additional problem that it’s a bit difficult to turn up the sun twenty degrees or so to give yourself a hotter shower!

This is why “weatherize before you solarize” was one of the mantras of the 1970s-era energy conservation scene. Inefficiencies you can shrug off when you’ve got plenty of concentrated fossil fuel energy will cripple your attempts to make use of the diffuse heat that you can get from the sun; fix the inefficiencies first – that is to say, conserve the differences – and you’re in a much better position to begin using renewable sources. You may also save enough on your energy bills to make a solar water heater a bit more affordable.

The same logic can be applied in other ways. We’ve already talked about weatherstripping, caulking, and various kinds of insulation, all of which are ways of conserving the difference between the temperature inside the house and the temperature outside. Equally, if you live in a climate with hot summers and appreciate a cool shower now and then, insulate your cold water pipes as well. If you go down into the soil more than a couple of feet you get a relatively stable, cool temperature year round; water pipes that run underground keep the water fairly close to that temperature, and if you can conserve the difference between the place your water pipe comes out of the ground and the place where it connects to your shower head. you get cold water out of the tap at, say, 60° F. rather than 80°, which on a sticky July day on the nether side of the Mason-Dixon line makes all the difference in the world.

Still, it’s possible to take conserving the differences in a much broader sense, and when you do so, some very interesting possibilities unfold. Information, to return to Gregory Bateson’s useful definition, is a difference that makes a difference. The capacity for energy to do work is also a function of difference – differences in temperature, pressure, electrical potential, or what have you – and so, in yet another sense, is the capacity of material substances to fill their various roles in the biochemistry of a living thing, the nutrient cycles of an ecosystem, the exchanges of goods in an economy, or the equivalent processes in any other system. In all these cases, the conservation of difference plays a crucial role, and there’s a sense in which the degree of conservation of the various kinds of difference is a measure of the health of the whole system.

This is all the more interesting in that for some decades now, modern industrial civilization – and in particular its American expression – has become very poor at conserving differences. To cite only one example, American farmers used to be legendary for the facility with which they bred new varieties of any crop you care to name, specially suited to local conditions or to particular purposes. These days, by contrast, American industrial agriculture is more notable for its obsessive use of a very small number of varieties of any given crop. Plenty of factors feed into that flattening out of differences, to be sure, but that’s exactly the point – the structures that shape everyday life in contemporary America do not conserve difference. Thinking over other examples of civilizations in decline, it occurs to me that a case could be made that the failure to conserve difference may just be a useful sign that a society has started to unravel in a serious way.

All this is grist for the speculative mill, and might be worth following out in detail. In the meantime, though, if you haven’t started conserving difference in your own home hot water and heating systems, get busy and wrap your pipes! Your local hardware store can provide you with a variety of materials, from foam tubes slit down one side that you can pop over your hot water lines, through fiberglas wrap that will do a good job on pressurized hot water heating system pipes, to the slightly more expensive but very effective rolls of foil-backed foam, which you can use on pipes or ducts equally well and will save you a chunk of heat. None of it’s that costly, all of it can be installed by unskilled labor, and any of it will cut into your energy bills and make your home a good deal more suited to the renewable energy projects we’ll be discussing in the weeks immediately ahead.

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