If you've been reading for a while, you might want to swallow and put down the coffee cup. I've posted several times about technological progress and have been favorable to it. And it's correct to think that I'm favorable to technological improvements and expect more to come.
But not all uses of technology represent progress. And not all things can be cured by technology.
I first recognized over-optimism about technology when I was taking physics in college. We had gotten to discussing how particle accelerators work. The professor noted that a certain design (the cyclotron, if I remember right) was limited in how fast it could accelerate particles because eventually you couldn't switch the electric field fast enough. You were limited by the speed of light in this. One of my classmates promptly suggested that there was no problem -- just have a computer do the switching. ... er, computers are also limited by the speed of light. But 'computers can solve all problems' was a popular idea even back then.
This weekend, I encountered a reminder about what I'll call technological regress. For progress, the new technology lets you do old things better/cheaper/faster. At least two of those. I was at a small road race. Small enough that the traditional old technologies would have worked fine -- stand someone at the finish line with a stopwatch, clipboard, and pen to take times and order, and another person with popsicle sticks or pieces of paper (numbered) and a pen to take names. Zero set up time, and almost no more time after the end of the race to have complete results. Plus, you have partial results available at any time.
The regress was to get a computer involved. Higher tech, but poorly suited to the job. The computer required data entry before the start of the race, which delayed things by about 15 minutes. And it can produce no results until after the last runner finishes and you feed the electronic timer (much more expensive than a stopwatch) results in to the computer. First runner finished in about 17 minutes, last in 51. That's a long time to wait if you don't have to. And, with only 20-30 runners, you shouldn't have to. (I've done the low-tech version myself for races up to about 150 runners. I wouldn't want to go past that, but up to about 100 is no problem.)
I'll leave off here and invite comments as to technologies regarding climate change prevention, mitigation, or adaptation, and your thoughts -- and reasons for thinking so -- as to whether it's overoptimistic to expect them to work (as cheaply as advertised, at least), and whether some might be technological regresses. Conversely, what technologies show some serious promise to provide real progress regarding climate change prevention, mitigation, or adaptation?
09 March 2010
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13 comments:
Where I live, rooftop solar should be a requirement with its panels cooled by heating the water for the household and pool. To store the solar-generated power, I imagine a chimneylike structure attached to every house that contains a weight on a geared, racheting mechanism that hoists the weight using power from the solar panels (hopefully, the structure won't worsen the earthquake hazard). Then, the utility company can detect which are loaded and turn them on via smart meters to meet peak loads.
I'm also intrigued by seasalt-based aerosols that enhance existing marine cloud albedo using more of natural aerosol.
Fun topic.
jg
What's with PC Timer? It's the same but you can also manipulate the preliminary results in real-time.
The comment by jg reminded me of an example of technological regress. Several decades ago, "rooftop solar" meant water warmers. Recently we find less of them. We depend more on natural gas or electricity when we want warm water.
As jg suggested, heat generated at photovoltaic cells can be considered as by-product rather than waste if there is needs of warm water. This is co-generation of power and heat, and it seems to be a good thing when both are available on site.
I also agree wigh jg that storage of solar energy is a very important issue where we need technological development, though I do not understand his particular idea precisely.
By the way, co-generation is perhaps a bad thing if it involves deliverly of heat (perhaps as steam). An engineering scientist recommends that power stations should strive for efficiency in generation of electric power, and that consumers should use electric heat pumps when they need heat.
One very destructive regress is when people choose to take the car for distances where it would be just as fast or even faster to walk. Sometimes this is encouraged by city planning that makes walking difficult.
Thomas:
I've seen some articles here about the design of newer (than 1940s) suburbs. One can pretty well match when the suburb was built with how much people walk -- the newer the area, the less they walk. My area has many gaps where there is no sidewalk and no shoulder. So, though most of the distance between me and the post office, convenience store, high schools, ... has sidewalk or at least a shoulder, I can't walk or bike to any of them without it being a life-threatening experience. (For the same reason, it messes up my running opportunities.) Arrgh! And, as walking around is a good contributor to health, you can also map health issues against age of area's development.
Kooiti:
Could you ask your engineer friends about this? Or maybe you know yourself. Heat pumps are, let's say, 40% efficient at turning electricity in to home heating. A furnace is upwards of 95% efficient at turning fuel in to home heating. The thing is, if the electricity is produced by burning the same sort of fuel as the furnace, electrical production itself is something like 40% energy efficient. Fuel -> electricity -> heat pump -> heating, then, looks to me to be about 16% efficient, versus the 95% of burning the fuel yourself.
The CO2 savings would be if the electricity came from something other than fossil fuels. But my electricity, for instance, is generated almost solely by fossil fuel. It'd be, I think, a big step backwards on CO2 emissions for someone in my area to use a heat pump rather than burn the fuel themselves.
What am I missing that leads your engineer friends to their conclusion?
Heat pumps can take heat from outside air, so it can give more energy than electricity it consumes. So it is much more energy resource saving than turning electricity into heat. This idea is promoted in a book written (in Japanese) by T. Hamamatsu, an engineering scientist who was behind development of a new type of heat pump for households which uses carbon dioxide in supercritical state (no distinction between liquid and gas) as the working fluid (so it does not use CFC).
180 channels and nothing's on!
Banking fees for ATMs.
Wonder cars that get the same mileage as cars of 30 years ago.
Graphing calculators in the classroom.
stainless steel knives (vs carbon steel).
(pet peeve) clothes irons!
Condiments in squeeze bottles (hard to use + they waste).
Plastic milk jugs that dribble.
To elaborate on Kooiti's response, a heat pump typically produce 3-4 times as much heat as you'd get from using an electric heater directly. Even with losses in generating the electricity this is more efficient than burning the fuel locally for heat. To what extent cogeneration is profitable is a more tricky question. My impression is that it makes sense if you can use the heat reasonably close to the power plant, but there is a lot of optimizing in calculating what mix of heat and electricity maximizes total efficiency.
Regarding Kooiti's comment that he's not sure that he understands my idea. Let me elaborate. I was offering the suggestion as something with potentional. Excess solar energy would be stored as potential energy in a weight. (I guess it's my answer to a flywheel. For some reason the speed of a flywheel and the tendancy for it to rotate as the earth turns unnerves me.) I wonder if a weight can capture as much energy as a flywheel.
Power companies now set up arrangements with consumers so that the power company can turn off household air conditioners for 1/2 hour periods at times of peak demand. Same means could detect the position of a weight and then turn on a small falling-weight-powered generator.
My next assumption is that if solar panels can trickle their power onto the grid, a weight-powered one could do as well.
Capturing excess solar power by hoisting a weight was inspired by a pumped storage proposal near my community. The pumped storaged would return 80% of what went in (while destroying a riparian canyon and losing money), so I thought a small motor, weight, racket and gearing mechanism could be that efficient turning a crank rather than pumping water to a reservoir where there are losses through evaporation. Also, the household weight generators could be turned on as fast as the pumped storage generators (it's one valid asset, I think).
If this is flawed, I'll happily relabel it as a regress.
jg
jg, try to do the math! You need an impractically large weight to store any useful amount of energy. A flywheel is a lot more realistic if you want mechanical storage.
Kooiti and Thomas:
Thanks for the further information. I was applying carnot efficiency considerations -- how much mechanical work you could extract from a heat engine. But, after I found a description of the coefficient of performance, see that the ideal heat pump -- using mechanical work to move heat -- has the inverse (ideal) efficiency. So, the heat pump's efficiency can indeed make up for the loss of energy from electrical generation and distribution.
jg: I've had the same idea as you, and then did the math Thomas suggests. Consider 1 kg of water. It will take 4000 Joules to heat it by 1 C. If I raise it 1 meter, however, it stores only 10 Joules of gravitational potential energy. That 400:1 factor makes lifting weights an enormously inefficient way to store energy. If I move the mass instead, the energy stored is equal to the 1 C heating once I've got the mass moving about 90 m/s (200 mph). Seriously high speed flywheels do that, but last (3-5 years ago) I saw, they weren't ready for industrial scale use.
Thank you, Thomas and Bob, for your criticisms. I enjoy this blog largely because I don't know where to start with most of the math. The answer leaves me wondering about pumped storage projects. If moving mass uphill is really so inefficient on the small scale I suggested, why do I have to fight so hard to prevent a large scale project from being built?
thanks,
jg
I understand jg's idea and I agree that we should pursue potential energy as a possible way to store energy. If we want mechanical energy or electricity, it is inefficient to store intermediate energy as heat. I said warming water is also useful, but it is only if part of our final demand is heat.
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