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Old 17-01-2017, 10:02   #46
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Re: Turn calories into electricity?

WWII radios were likely orders of magnitude less efficient than today's radio's.
However, I bet they were well less than 1 watt and relied on efficient antennas and not brute power to get through, gotta think part of that may be a low power station is more difficult to DF?
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Old 17-01-2017, 10:21   #47
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Re: Turn calories into electricity?

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Originally Posted by boatman61 View Post
15 minutes to trim sails after a tack.. what are you sailing a brigantine..???
A 40m solo trimaran named Spindrift 2.
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Old 17-01-2017, 10:35   #48
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Re: Turn calories into electricity?

Kinesiologists agree, I believe, that a fit man can generate 1/10 horsepower in spurts, and about half of that over prolonged periods, i.e. for some few hours at a time.


Some fundamentals:


  1. Garbage in —> garbage out.
  2. Power in – losses = power out
  3. Volts x Amperes = Watts
  4. 1 HP = 750 W (appr.)


So: .05 HP = (750 * .05) W = 38 W (appr). At 12V, 38W = 12 * A, i.e. (38/12) A or a shade over 3 A. So 3 amps or thereabouts is all that a fit man, pedalling a 12V generator like fury and doing NOTHING else, can provide over a prolonged period. And that's BEFORE you even think about the losses in the system.


To open, and keep open, the solenoid valve on my propane supply for the galley and to keep the dome light over the stove lit at the same time requires 4 amps according to my ammeter.


And that's why keeping a 120V 75W incandescent light bulb lit for even five minutes knocks the wind out of you.


I'd love to know how many KWhs are “sequestered” in TrentePieds' hull – frozen snot made from crude oil – and in her sails – Dacron, also made from crude oil. Not to mention in the steel in her engine, steel that was smelted using coal or oil depending on just where it was made. And in smelting the beauxite from which her spars are made. Aluminum manufacture is a NOTORIOUS energy hog, and we may thank the Military Industrial Complex for its existence. I would also love to know how many KWhs will be consumed in destroying my toy when her time comes.


I think it's appropriate in any discussion of “alternate energy” in respect of yots to acknowledge that the “greenest” approach of all is not to make them in the first place. I'm not likely to find many acolytes for that position :-)!


But perhaps I'm barking up the wrong tree. I understand that places like Scranton PA are to be “made great again”?


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Old 17-01-2017, 10:47   #49
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Re: Turn calories into electricity?

Quote:
Originally Posted by Dennis.G View Post
No fair! He had to heat both sides
of the toaster but only make one
slice.. They should have shut down
the other side of the toater and he
would only have to create half the
power. Why aren't these things
taken into consideration when
experiments are undertaken?
See how hard it is? Ridiculous.
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Old 17-01-2017, 10:59   #50
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Re: Turn calories into electricity?

I know that was in jest, the take away is look at that guy, and it was all he could do to make 700W for less I believe than 1 min, and it took all he had.
It should make us appreciate the enormous power that is in our battery banks, how big a job an alternator or Solar has in replenishing them, and just how much power there is in a teaspoon of Diesel fuel.
The four Solar panels I have put out more power than that guy on the Video can, when you think of that, its impressive how much power those things harness, just sitting there.
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Old 17-01-2017, 11:24   #51
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Re: Turn calories into electricity?

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Originally Posted by jongleur View Post
They should have shut down the other side of the toaster and he would only have to create half the power.
Gotta admit I had the same thoughts. They could have cut it down to a single slice toaster and not had 1 empty slot burning energy for nothing. Or they could have dropped in 2 slices and given him twice the reward for the same energy spent.

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Old 17-01-2017, 11:30   #52
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Re: Turn calories into electricity?

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I know that was in jest, the take away is look at that guy, and it was all he could do to make 700W for less I believe than 1 min, and it took all he had..
True, but I bet he could output 350W for several hours. That's a lot of toast with a one-slice toaster.

Mere humans will have cold toast, but charging a cell-phone and juice to run LED lamps is well within reach (Most of my overnight needs). But the fact remains that installing a bike trainer on a small boat like mine will be quite impractical - there's a reason my bike remains folded while onboard.
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Old 17-01-2017, 11:47   #53
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Re: Turn calories into electricity?

If you have all the bread, you could have the toast brought in by helicopter. Funny how these "discussions" deteriorate. I was reading one segment, where the nays simply increased the power needs to show that a bicycle type generator would not work. The bottom line remains, if it adds to your electric supply, if you can find out at what level, and if you are willing and able (able being a very operative word in many ways), you get to decide what you do, not some rusty, semi-impaired old fart like me or some young, fit person like _____ (fill in name).
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Old 17-01-2017, 11:50   #54
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Re: Turn calories into electricity?

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True, but I bet he could output 350W for several hours.
He could, very likely. Could most of us? I don't think so. I feel real sure a single 100W Solar panel would whip me on a daily basis.

I used to be what I considered a bicyclist, rode a Lightspeed Ultimate and did regular Centuries, rode regular 200 mile weeks. Rode with a small bike club in the hill country of Tx in 92 I think it was, but they ate my lunch, I couldn't keep up even wheel sucking. When I left Tx and was transferred to Germany, I bought a set of rollers so I could ride during the Winter. I quickly discovered two things, first just how incredibly hot and sweaty I got in even a cold house, you have to have a fan or you will die of heat.
Secondly just how incredibly boring riding rollers is, and how tough they are, they are like riding into the wind, or a hill that never ends.
If you can grind out a couple of hundred Watts for a couple of hours, you have my respect, and I think you would smoke Joe average cyclist
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Old 17-01-2017, 12:44   #55
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Re: Turn calories into electricity?

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Originally Posted by foufou View Post
While many of us are past our prime the possibility of generating a third of a horsepower is far from impossible. When I was younger I once hiked up a mountain side and just based on foot pounds per hour; ie my weight x change in elevation X time, I produced a third of a horsepower. Friends at the time could do likewise. So while our geriatric cruisers might not achieve these numbers it is still a way to get exercise and produce some electrical energy
/ time
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Old 17-01-2017, 15:46   #56
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Re: Turn calories into electricity?

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It takes 300 to 400 watts to sustain Human powered flight, and there are very few people that can do that. I'm talking kids who are Pro athletes. I know compared to my prime, physically I am a joke. I'd bet few of us could sustain 100 W, its harder than you think. I have pedaled a bike set up as a demonstration running a small portable TV that pulled I think about 60W, and had to pedal my butt off, I could not have sustained it for too long, and that was when I was younger.
It's one of the things that really impressed me at just how much power there is in things that generate heat. You would likely work yourself nearly to death to generate enough heat for a cup of tea.
Lets assume your cup = 250 ml
Ambient temperature = 20 °
So if you want to use boiling water to make your tea, you need to generate 250 * 80 = 20k calories of heat = 1163 Wh.

Assume 80% efficiency of generator/heating coil that's getting close to 1.5kWh.

So if you can sustain your 100W, it will only take you 15 hours to make your cup of tea. Or to put it another way, that cup of tea takes at least as much energy as is expended by a top TDF rider riding a full stage.
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Old 17-01-2017, 16:27   #57
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Re: Turn calories into electricity?

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Lets assume your cup = 250 ml
Ambient temperature = 20 °
So if you want to use boiling water to make your tea, you need to generate 250 * 80 = 20k calories of heat = 1163 Wh.
It's not like you to be 2 orders of magnitude out ... 20000cal = 84000J = 84000/3600 = 23.3Whr

The tea should be ready in 20 minutes (assuming no heat loss).
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Old 17-01-2017, 16:29   #58
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Re: Turn calories into electricity?

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Originally Posted by a64pilot View Post
He could, very likely. Could most of us? I don't think so. I feel real sure a single 100W Solar panel would whip me on a daily basis.

I used to be what I considered a bicyclist, rode a Lightspeed Ultimate and did regular Centuries, rode regular 200 mile weeks. Rode with a small bike club in the hill country of Tx in 92 I think it was, but they ate my lunch, I couldn't keep up even wheel sucking. When I left Tx and was transferred to Germany, I bought a set of rollers so I could ride during the Winter. I quickly discovered two things, first just how incredibly hot and sweaty I got in even a cold house, you have to have a fan or you will die of heat.
Secondly just how incredibly boring riding rollers is, and how tough they are, they are like riding into the wind, or a hill that never ends.
If you can grind out a couple of hundred Watts for a couple of hours, you have my respect, and I think you would smoke Joe average cyclist
Um, a 100w panel would kick the stones out of Lance Armstrong when he was juicing.

Let's assume a normal human during a 1hr work out routine generates 100wh on average. In the tropics with 6.5hr of sunlight you would need a 15.4w panel to generate the Sam evidence amount. This pretty much works out to the largish end of those 'folding' panels they sell to keep the batteries charges on your car while you are on vacation.

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Old 17-01-2017, 17:50   #59
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Re: Turn calories into electricity?

Why bother with generating electricity? Get one of these:

https://www.roadtechmarine.com.au/fr...board/p/MMC230


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Old 17-01-2017, 18:16   #60
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Re: Turn calories into electricity?

Quote:
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It's not like you to be 2 orders of magnitude out ... 20000cal = 84000J = 84000/3600 = 23.3Whr

The tea should be ready in 20 minutes (assuming no heat loss).
Doh!

(Mixed up cals and kcals doing the conversion.)

I've asked the mods to delete my post so that incorrect info doesn't hang around
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