The Mechanical Transmission of Power – Jerker Line Systems
lowtechmagazine.com
lowtechmagazine.com
> Why do this instead of powering each device individually? One: you save three electric motors. Two: there is no need to provide batteries or electric outlets at any of the locations. Three: you can balance the system so that one device helps power the other, saving a considerable amount of energy.
Pairing rocking machines like this is a real efficiency improvement, especially with IC and steam engines where you don't really have the option of capturing the return stroke's energy directly. Even with an electrical system, where this is possible, it would add a whole lot of complexity.
> In these cases, you can distribute mechanical energy without conversion losses.
Without conversion losses, maybe. However, you are going to lose a lot of energy to friction (especially if you have a lot of the rocking posts, friction posts, hold-downs and so on). Also, unless the rods connecting the machines are perfectly elastic you're going to lose a bunch of energy to heating the rods themselves.
You can have all the "Doubts on progress and technology" you want, but if you only count one kind of loss (electrical conversion) and not another (mechanical friction and inelastic fraction) you're going to end up with a non-realistic bias in favor of mechanical systems every time.
I've been wondering for a while whether anyone's trying to re-capture some of the "lost" energy from household electrical systems. I wonder why my fridge, aircon, and stove aren't "pre heating" the cold water going into my hot water heater? I even wonder why all my "fixed electronics" - I'm looking at the TV, Playstation, audio gear, media center PC, home networking gear - have all got heatsinks and fans "disposing" of "waste heat" (which I sometimes then spend more money dealing with by cooling the room down with aircon).
Is there _really_ no good way to capture all that "waste heat" and use it to offset the energy I consume having a hot shower every day?
(I'm guessing I'm not the first to ever have these thoughts, and that the answer right now is "power is so cheap that the payback time for any available technology that could do this is way longer than practical". Which satisfies the pragmatist in me, but still makes the tree-hugger in me slightly melancholy.)
This is also the reason why low-energy light bulbs are less profitable in certain countries.
I guess that your comment probably reveals another reason why this idea isn't currently economically feasible - the "richest market" where the pre-conditions for it to work (households with significant amounts of "waste heat generating electronics" running permanently or close to), is surely the USA and the 2nd richest market is probably western Europe. Both regions where for a large part of their population, the climate is cold enough for significant parts of the year for your simple solution to be "good enough". A market the size of Australia (~20million people) probably isn't anything like big enough to get the economy of scale to work.
Now my tree-hugger side is even more melancholy...
Check out "The Plan" for the larger scale objectives.
The economic equivalent would be:
You: "Hey Bob, those are expensive fishing trips. Think of the opportunity cost!"
Bob: "Thanks, you've saved me a bundle. I'll go quit my job immediately!"
(The effect you're citing is real, but the explanation is more basic: at low energy costs, efficient goods have longer payoffs. This happens regardless of what heating method people use.)
First, heat pumps were very uncommon until only a few years ago, since no one needs A/C in this cold climate. A heat pump can have a 10-year payoff with our electricity costs, although this has gotten better in recent years. There is no gas infrastucture. And it makes no sense to switch to high-energy appliances untli you're switched to more efficient heating.
I asked the CEO of SunFrost (who make super-efficient fridges for solar houses) whether he had examined the possibility of a water-cooled refrigerator. He said that people didn't want to pay a plumber to install and remove their refrigerator, and that the lifetime savings doesn't really pay for the extra time and hardware.
Also I think some old customs were really ecological just because of being used to scarce resources. For example - my grandpa have old ceramic stove for cooking in the kitchen. It has pipes with water inside - additionaly heating water for washing, when you cook. I've always thought it's a great idea.
My grandma also had big plastic bucket in the tube in the bathroom, when you washed your hands during the day you did it over that bucket. When you needed to flush the toilet, you first used the water from that bucket, only if it was empty you used built-in "flusher".
These things weren't really needed anymore, but that generation got used to not waste anything.
According to my father, my grandfather would go to the central hub and grab hold of one of the lines for a few moments, then to the next and the next. He could tell by the way the line was moving and felt if there was a problem down field he needed to attend to.
I never quite "got" what he was talking about in my mind, and my father was very young when he saw them in action so I never really had a great explanation of what these "lines" were.
Great post and finally fills in a gap in my father's childhood stories.
[1] - they looked something like this https://www.youtube.com/watch?feature=endscreen&NR=1&...
> The technology, which still operates in a handful of small oil fields, could also work with renewable energy sources, and shows great potential for efficient small-scale energy use.
It looks like the modern version of this technology can be useful today. My guess is that the energy is more efficiently transmitted by electricity (electric resistance vs. mechanical friction), but it's more expensive to put and maintain a electrical motor in each final node. But I don't have enough information, I'd like to see some real numbers.
Low-Tech Magazine has, surprise!, a pro- low-tech bias.
Over short distances we already use mechanical energy transfer all the time (drive shaft in cars, chains in bikes, etc.), this takes the same idea and extends it to a longer distance.
My hunch is that while it would still work in theory, electrical systems would win out because of construction costs and maintenance. Motors and generators are widely available, wire gets laid once and works for decades, and contractors know how to deal with all of it. A jerker line needs more frequent lubrication, has custom parts that wear out, and when they do you can't just say "I need a new NEMA 6 motor" and have it in a day.
EDIT: Also worth noting that the high efficiency numbers for the electrical system are going to be at peak load, if you run it at partial they'll drop. The frictional losses on a jerker line are probably a bigger percent of the total at part load as well, but I don't know whether they'd be more or less significant than a generators'.
Regarding replacement, I suspect that in an oilfield in the back of beyond in the late-19th/early-20th century, many of the replacement parts for these systems would be made on-site with a saw or a farrier's anvil.
For multi-legged robots, a bit of smart geometry can pretty much do this already - see these things: http://www.strandbeest.com/
I suspect using some computer-adjustable versions of the "multipliers" from the article would allow you to build something like a strandbeest which you could steer while only losing a little of the efficiency.
Well not so smart in itself but very cleverly used.
First steam-powered cable-car systems were also at the end of the 1800s.