Free Power Generation- Whats Wrong With My Idea?
Discussion
As I was taking off from Heathrow earlier I started thinking about airships and how much more interesting flying on one of these would be than a packed airbus A319.
My idea was for something like an airship to take off from the ground floating upwards using helium. It carries with it a cable which is attached to a reel on the ground attached to a generator. The resistance of the generator/reel is such that when released the airship will climb slowly taking the cable and turning a generator. When the airship reaches say 1km altitude an on-board compressor partially reduces the helium volume so it starts to lose altitude. The reel is decoupled from the generator so the cable can be wound in without the resistance from turning a generator. When it gets to the ground it repeats the process (assume no wind so it lands in same place)
I know there is no such thing as a perpetual motion machine so what is wrong with this idea?
My idea was for something like an airship to take off from the ground floating upwards using helium. It carries with it a cable which is attached to a reel on the ground attached to a generator. The resistance of the generator/reel is such that when released the airship will climb slowly taking the cable and turning a generator. When the airship reaches say 1km altitude an on-board compressor partially reduces the helium volume so it starts to lose altitude. The reel is decoupled from the generator so the cable can be wound in without the resistance from turning a generator. When it gets to the ground it repeats the process (assume no wind so it lands in same place)
I know there is no such thing as a perpetual motion machine so what is wrong with this idea?
Mr Pointy said:
Where do you get the energy from to run the compressor & winch?
Would the energy required to reel the cable back in as the airship descended under gravity and the energy required to compress a volume of the helium to get the airship to descend be greater than the energy generated from the ascent? bunchofkeys said:
Where does the helium come from, and how much energy is needed to produce it, pump it into the airship?
That would surely negate any gains from what is made with your configuration?
I don't know how much energy it takes to produce the helium however I don't think helium would be used in the process overall once the airship had been initially filled (except for leaks).That would surely negate any gains from what is made with your configuration?
Tim330 said:
I don't know how much energy it takes to produce the helium however I don't think helium would be used in the process overall once the airship had been initially filled (except for leaks).
You could do sort of the same thing in negative with a 'submarine', without faffing about with rare and leak-prone gasses like helium.But I suspect that since in both cases, you're using the change in volume of the gas to provide the working 'lift', you'd find that the energy required to compress the gas + pumping efficiency > than the amount of energy you'd gain in lift.
All energy generation is "free"
The only thing that matters is the cost to extract a unit of electricity and the rate at which electricity can be extracted.
For example, nobody pays the sun to shine. But to leverage solar energy we have to make solar panels, inverters, wire them up, mount them somewhere, repair them when they break, replace them when they are worn out. Same with coal. Coal is free, you litterally just dig it out of the ground. What costs money is the mine, the diggers, the miners, the graders, the transport systems etc etc etc Same with wind power (the wind blows for free) same with etc etc etc
Your airship idea has actually being trialed with kites, where the net power comes from being able to orient to create lift on the kite to pull the winch as it climbs, and then re-orient it to kill the lift so it descends.
The issue is that the actual amount of energy you get out is relatively speaking tiny, and currently the system does not scale very well. Things like wind turbines and even coal fired power stations are most cost effective the bigger they get, and it's the same with kites / airships.
The only thing that matters is the cost to extract a unit of electricity and the rate at which electricity can be extracted.
For example, nobody pays the sun to shine. But to leverage solar energy we have to make solar panels, inverters, wire them up, mount them somewhere, repair them when they break, replace them when they are worn out. Same with coal. Coal is free, you litterally just dig it out of the ground. What costs money is the mine, the diggers, the miners, the graders, the transport systems etc etc etc Same with wind power (the wind blows for free) same with etc etc etc
Your airship idea has actually being trialed with kites, where the net power comes from being able to orient to create lift on the kite to pull the winch as it climbs, and then re-orient it to kill the lift so it descends.
The issue is that the actual amount of energy you get out is relatively speaking tiny, and currently the system does not scale very well. Things like wind turbines and even coal fired power stations are most cost effective the bigger they get, and it's the same with kites / airships.
Max_Torque said:
Your airship idea has actually being trialed with kites, where the net power comes from being able to orient to create lift on the kite to pull the winch as it climbs, and then re-orient it to kill the lift so it descends.
Not really the same thing at all: kites are exploiting wind power (and we all know that there are easier ways to do that with rotating turbines). The airship idea relies upon a cycle of displacement and compression of gases.Equus said:
Not really the same thing at all: kites are exploiting wind power (and we all know that there are easier ways to do that with rotating turbines). The airship idea relies upon a cycle of displacement and compression of gases.
Airships generate part of their lift from their shape. In the case of the Airlander 10, it may be as much as 1/3, hence the term for it of 'Hybrid Air Vehicle'.As no wind at all is quite rare, Tim330's idea would work with an airship (or kite balloon in this case, to be pedantic) simply by changing the incidence of the airship relative to the winch line. It is unlikely to be the cheapest way of developing this power though.
These things do have their issues though. I stayed in digs in Acocks Green, Birmingham, for a while, and reading about the wartime history of the place, apart from a couple of stray bombs aimed at the Rover tank engine factory, which destroyed a couple of houses, the bulk of the damage was caused by a barrage balloon in a strong wind which took most of the chimneys off the houses in the street!
[i] 10th August 1940
While we were having a peaceful night's sleep last night people near us were having a very trying time, for “Janet” our balloon ran wild during the early hours of the morning – broke branches from trees, swept chimney pots and chimneys from the roofs of houses from here to just beyond the Swan at Yardley. Five houses were damaged down Augusta Road, and nearly all the houses down Wynford Road suffered damage. Then the cable swept across and removed chimneys from houses opposite the cemetery, and then had its final fling at the Swan Hotel and some shops near it, and across the road where the chemists at the corner sustained a deal of damage. [/i]
Acocks Green Wartime Diary
Edited by GliderRider on Tuesday 22 January 11:04
Edited by GliderRider on Tuesday 22 January 11:06
Tim330 said:
I don't know how much energy it takes to produce the helium however I don't think helium would be used in the process overall once the airship had been initially filled (except for leaks).
1) You're going to leak like a sieve. Helium is really hard to contain because it's such a small molecule.2) Compressing the helium to lower its volume sufficiently that it becomes denser than air will take more energy than the lift generates.
3) There isn't much helium around and we're pissing it away into space at a fair rate. Short of fetching it down from the moon, when we run out of terrestrial helium we are pretty much stuck.
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