Generating power through displacement.

AI Thread Summary
Generating renewable energy through displacement using pressure differences is theoretically interesting but practically unfeasible. The concept involves using a submerged cylinder to displace water and drive a turbine, but the energy produced will never exceed the energy required to remove the water. The law of conservation of energy dictates that energy can only be transferred, not created or destroyed. In ideal conditions, energy output could equal input, but real-world efficiencies drop this to about 20-30% of the input work. Ultimately, the proposed method is not a viable source of renewable energy.
Mulith
Messages
1
Reaction score
0
Hi there.

I've been looking at whether it's possible to create renewable energy though the use of diplacement and taking advantage of pressure differences. Let me explain.

Lets say you had a cylinder 100m x 50m. At the bottom of this cylinder you had multiple inlet pipes. The cylinder is then dragged down into the water using a weight of some kind so as to displace the water. The pressure at that depth, if I'm not mistaken would be 145.304 psi. The water is then allowed to pass through the inlet pipes to drive a turbine which then pumps the water out and over the edge of the cylinder. What I want to know is whether the energy created is likely to be greater than the energy required to remove the water from the cylinder?
 
Engineering news on Phys.org
I think you may already know the answer to the question: The law of conservation of energy applies.
 
Mulith said:
What I want to know is whether the energy created is likely to be greater than the energy required to remove the water from the cylinder?

No it definitely won't be greater. At the very best, it would be the same if the machine had an efficiency of unity.

CS
 
Energy Can Neither Be Created Nor Destroyed; Can Just Be Transferred From One Form To Another.
This Idea Is An Illusion Like Perpetual Motion Machines.
 
i remember when i used to get out of the box ideas in school and i thought i was a genious ;))
 
Mulith said:
What I want to know is whether the energy created is likely to be greater than the energy required to remove the water from the cylinder?

No. In theory and an idealistic situation, it will be exactly equal. In practice, it will always be less.. less by around 20-30%.
 
It's much, much less than that. You might get a turbine efficiency of 65%, then a generator efficiency of 95%, then a motor efficiency of 95%, then a pump efficiency of 65%. That's an overall efficiency of 38%.
 
russ_watters said:
It's much, much less than that. You might get a turbine efficiency of 65%, then a generator efficiency of 95%, then a motor efficiency of 95%, then a pump efficiency of 65%. That's an overall efficiency of 38%.

oops.. i stated it wrong.. What i was meaning to say is, "Output energy is 20-30% of input work".
 
Back
Top