Transfer of electrical energy and transfer of air energy

  • I
  • Thread starter sam286
  • Start date
  • #1
sam286
10
3
Is there a way to know what is the amount of energy a wire can transport and know what is the amount of energy transported by moving air at a certain psi.
 

Answers and Replies

  • #2
russ_watters
Mentor
22,054
9,151
Is there a way to know what is the amount of energy a wire can transport and know what is the amount of energy transported by moving air at a certain psi.
Welcome to PF. Those seem like two mostly unrelated questions:
1. Electrical energy (power) carrying capacity in a wire is a function of wire size (which dictates amperage) and voltage. There is no single maximum for a given wire.
2. Energy transport by moving air is a function of both flow rate and pressure. But you didn't say anything about how the air is being moved, so I can't be any more specific than that.
 
  • #3
sam286
10
3
Welcome to PF. Those seem like two mostly unrelated questions:
1. Electrical energy (power) carrying capacity in a wire is a function of wire size (which dictates amperage) and voltage. There is no single maximum for a given wire.
2. Energy transport by moving air is a function of both flow rate and pressure. But you didn't say anything about how the air is being moved, so I can't be any more specific than that.
Yes I now realize that my question was not precise enough so I will explain to you the hole problem and I hope it will be more clear if not fell free to ask for clarification





I would like to transfer energy from a point A to point B and all the weight need to be at the point B the energy is produce and process at the point B and point A transport, receive and use the energy. I was thinking of a small wire whit the highest voltage as possible (without hover heating the wire) to reduce the size of the wire and whit that the weight and a transformer at point A to adjust the power to be use. But my problem is that if I want more energy, I need more wire and the more wire the weight, the more weight more power needed, the more wire, you see the problem here. Also, the more distanced the to point are the more wire and more weight and we have the same problem again.




I also think about a pressured air line whit the highest pressure as possible and a generator at point A to transform the air pressure energy into work energy. I know the more pressure the stronger the air line needs to be and the further the heavier. But the air in the tube ways significantly less that the copper in the wire.


So I would like to found a way to calculate the potential energy transfer versus the weight.
 
  • #4
russ_watters
Mentor
22,054
9,151
I would like to transfer energy from a point A to point B
How much and how far?
and all the weight
Weight of what?
But my problem is that if I want more energy, I need more wire and the more wire the weight, the more weight more power needed, the more wire, you see the problem here. Also, the more distanced the to point are the more wire and more weight and we have the same problem again.
No, larger wires don't require more energy. I'm not even sure what exactly you might mean by that.
I also think about a pressured air line whit the highest pressure as possible and a generator at point A to transform the air pressure energy into work energy. I know the more pressure the stronger the air line needs to be and the further the heavier. But the air in the tube ways significantly less that the copper in the wire.
A wire can carry more electrical power than a tube/pipe of the same weight carries air power. And more efficiently.
So I would like to found a way to calculate the potential energy transfer versus the weight.
You'll still need to be more specific about the scenario, but there's tables of wire size and ampacity and I'm sure you could do the same for pipe size and flow.
 
  • #5
russ_watters
Mentor
22,054
9,151
Here's a sample: A 12 gauge wire at 120V carries up to 20A in normal conditions, or 2,400W and weighs 0.028 lb/ft.
 
  • #6
sam286
10
3
How much and how far?
Weight of what?

No, larger wires don't require more energy. I'm not even sure what exactly you might mean by that.

A wire can carry more electrical power than a tube/pipe of the same weight carries air power. And more efficiently.

You'll still need to be more specific about the scenario, but there's tables of wire size and ampacity and I'm sure you could do the same for pipe size and flow.
I understend the part of the wire sample

I will give you a crazy example to explain my self imagine a infinitely long road whit a electric car driving on it the electric car has no battery so you need to give it power from a wire. At the start you have infinite energy and power. The wire is tie to the car and the car start going forward the wire provide the car whit the power it need to go forward at the biggening the car pull it self and a small portion of wire and the further it goes the more wire it need to pull so the more power need to go through the wire so the wire need to be bigger. Now do you understand the wire size/power and weight part.
 
  • #7
russ_watters
Mentor
22,054
9,151
I understend the part of the wire sample

I will give you a crazy example to explain my self imagine a infinitely long road whit a electric car driving on it the electric car has no battery so you need to give it power from a wire. At the start you have infinite energy and power. The wire is tie to the car and the car start going forward the wire provide the car whit the power it need to go forward at the biggening the car pull it self and a small portion of wire and the further it goes the more wire it need to pull so the more power need to go through the wire so the wire need to be bigger. Now do you understand the wire size/power and weight part.
Fair enough. But I can't guess the details so I hope I've helped but I'm afraid I've given all the help I can at this point.
 
  • #8
sam286
10
3
Fair enough. But I can't guess the details so I hope I've helped but I'm afraid I've given all the help I can at this point.
Thanks for your help, I understand that whiteout a situation it’s hard to help it was just a question that came up in my mind and I try to explain my thinking and find a answers
 
  • #9
berkeman
Mentor
64,131
15,340
I understend the part of the wire sample

I will give you a crazy example to explain my self imagine a infinitely long road whit a electric car driving on it the electric car has no battery so you need to give it power from a wire. At the start you have infinite energy and power. The wire is tie to the car and the car start going forward the wire provide the car whit the power it need to go forward at the biggening the car pull it self and a small portion of wire and the further it goes the more wire it need to pull so the more power need to go through the wire so the wire need to be bigger. Now do you understand the wire size/power and weight part.
I initially assumed that there was a big language barrier in your posts in this thread, but now that I check your IP address, I see that you are basically in North America. Is there a reason that you are posting like English is not one of your two native languages?

I would like to reply to try to help, but I'm suspecting trolling on your part, so I'd appreciate hearing your response...
 
  • Like
Likes Bystander, russ_watters, dlgoff and 1 other person
  • #10
sam286
10
3
I initially assumed that there was a big language barrier in your posts in this thread, but now that I check your IP address, I see that you are basically in North America. Is there a reason that you are posting like English is not one of your two native languages?

I would like to reply to try to help, but I'm suspecting trolling on your part, so I'd appreciate hearing your response...
Its not a troll It was the first forums I find about general physics so its the one I use
 
  • #11
berkeman
Mentor
64,131
15,340
Its not a troll It was the first forums I find about general physics so its the one I use
Hmm, fair enough.

imagine a infinitely long road whit a electric car driving on it the electric car has no battery so you need to give it power from a wire. At the start you have infinite energy and power. The wire is tie to the car and the car start going forward the wire provide the car whit the power it need to go forward at the biggening the car pull it self and a small portion of wire and the further it goes the more wire it need to pull so the more power need to go through the wire so the wire need to be bigger. Now do you understand the wire size/power and weight part.
It's best not to think in terms of an "infinite power source" to provide power to the wired connection to the car. You can have a power source of some output voltage with a low source resistance, so it can supply a lot of current at that source point.

The limitation in getting power to the remote car is the resistance of the wire(s) connecting to the car. You can calculate that by knowing the Resistance of the wire per unit length (resistivity) ##\rho##, and as you say you can use larger diameter wire to get a lower Resistance per unit length in order to deliver more power to the remote car.

One very key point about powering a remote device is that if the remote device uses a switching power supply of some kind (which is the most efficient way to use the power delivered to it), there is an important limitation in how low the voltage on the wires can droop. Since the consumer of that delivered power (the switching power supply) is a "constant power converter", it turns out that it can operate in two different modes to deliver power from the wires to the load: (a) High Input Voltage and Low Input Current, or (b) Low Input Voltage and High Input Current.

When the car is close to the power source there will be little voltage drop across the wires, and the switching power supply will be operating in mode (a). But as you get farther away from the power source, the input voltage to the car droops, and it turns out that when it droops to half of the source voltage, the switching power supply snaps into mode (b) which is bad. It causes the voltage on the wires to drop out, and the device stops running.

So delivering power to very remote devices is more complicated than you might think... :smile:
 
Last edited:
  • #12
Lnewqban
Homework Helper
Gold Member
2,624
1,422
... I also think about a pressured air line whit the highest pressure as possible and a generator at point A to transform the air pressure energy into work energy. I know the more pressure the stronger the air line needs to be and the further the heavier. But the air in the tube ways significantly less that the copper in the wire.
If you can accumulate air, or water slowly, and then use as much of it when you need it, the tubes could have a very small diameter (which can resist higher pressures) and little weight.
 
  • #13
sam286
10
3
Hmm, fair enough.


It's best not to think in terms of an "infinite power source" to provide power to the wired connection to the car. You can have a power source of some output voltage with a low source resistance, so it can supply a lot of current at that source point.

The limitation in getting power to the remote car is the resistance of the wire(s) connecting to the car. You can calculate that by knowing the Resistance of the wire per unit length (resistivity) ##\rho##, and as you say you can use larger diameter wire to get a lower Resistance per unit length in order to deliver more power to the remote car.

One very key point about powering a remote device is that if the remote device uses a switching power supply of some kind (which is the most efficient way to use the power delivered to it), there is an important limitation in how low the voltage on the wires can droop. Since the consumer of that delivered power (the switching power supply) is a "constant power converter", it turns out that it can operate in two different modes: (a) High Input Voltage and Low Input Current, or (b) Low Input Voltage and High Input Current.

When the car is close to the power source there will be little voltage drop across the wires, and the switching power supply will be operating in mode (a). But as you get farther away from the power source, the input voltage to the car droops, and it turns out that when it droops to half of the source voltage, the switching power supply snaps into mode (b) which is bad. It causes the voltage on the wires to drop out, and the device stops running.

So delivering power to very remote devices is more complicated than you might think... :smile:
Thanks for your help now I understand more the situation. Its was what I thought, its complicate to transfer remote power. A part from using a wire is there a better way to transfer power in this situation.
 
  • #14
berkeman
Mentor
64,131
15,340
A part from using a wire is there a better way to transfer power in this situation.
It depends on the specifics of the situation. Many times it's better/easier to carry your energy source with you on the vehicle (gasoline for a combustion engine or charged batteries for an electric vehicle). Or if it's a sunny day, you could maybe use solar cells to tap the energy of the Sun for the vehicle.

If the vehicle is in space, you could use laser power for moving (slowly) near the Earth...

https://en.wikipedia.org/wiki/Laser_propulsion
 
  • #15
sam286
10
3
If you can accumulate air, or water slowly, and then use as much of it when you need it, the tubes could have a very small diameter (which can resist higher pressures) and little weight.
Yes that was my idea but will it be more efficient because you still have the weight of the water and in the case of air, (I think) pressure air is kind of heavy for the amount energy it can transport. You need to consider energy loss to because a air turbine or motor have (I think) is less efficiency than electricity. A other option I thought about is to use a gas mix like in rocket to make a combustion engine or a rocket propultion in this case I don’t now if it is better to transport the gas like oxygen and hydrogen in gas form or liquid form
 
  • #16
sam286
10
3
It depends on the specifics of the situation. Many times it's better/easier to carry your energy source with you on the vehicle (gasoline for a combustion engine or charged batteries for an electric vehicle). Or if it's a sunny day, you could maybe use solar cells to tap the energy of the Sun for the vehicle.

If the vehicle is in space, you could use laser power for moving (slowly) near the Earth...

https://en.wikipedia.org/wiki/Laser_propulsion
Thanks that is one more option that I can lock in to
 
  • #17
berkeman
Mentor
64,131
15,340
other option I thought about is to use a gas mix like in rocket to make a combustion engine or a rocket propultion in this case I don’t now if it is better to transport the gas like oxygen and hydrogen in gas form or liquid form
If your vehicle is in the Earth's atmosphere, you don't have to carry your own source of Oxygen with you (unless you need liquid Oxygen for some reason)... :wink:
 
  • #18
sam286
10
3
If your vehicle is in the Earth's atmosphere, you don't have to carry your own source of Oxygen with you (unless you need liquid Oxygen for some reason)... :wink:
That a very good point every way of propulsion have its benefit depending on the environment your in. Thanks making me realize that.
 
  • #19
Lnewqban
Homework Helper
Gold Member
2,624
1,422
Yes that was my idea but will it be more efficient because you still have the weight of the water and in the case of air, (I think) pressure air is kind of heavy for the amount energy it can transport. You need to consider energy loss to because a air turbine or motor have (I think) is less efficiency than electricity. A other option I thought about is to use a gas mix like in rocket to make a combustion engine or a rocket propultion in this case I don’t now if it is better to transport the gas like oxygen and hydrogen in gas form or liquid form
What I meant is that for certain power that you need (energy per unit of time), you could accumulate that energy (slowly flowing through a tube) during a long period of time.
Once you have certain volume of fluid accumulated above the required pressure, you can release it for your mechanical needs.

In other words: efficient generation, low power transmission, high power usage.

Both gasses that you have mentioned are explosive; nitrogen is normally used in similar cases.
 
  • #20
sam286
10
3
What I meant is that for certain power that you need (energy per unit of time), you could accumulate that energy (slowly flowing through a tube) during a long period of time.
Once you have certain volume of fluid accumulated above the required pressure, you can release it for your mechanical needs.

In other words: efficient generation, low power transmission, high power usage.

Both gasses that you have mentioned are explosive; nitrogen is normally used in similar cases.
Ok, now I understand what you meant and its a very good way to see the problem
 

Suggested for: Transfer of electrical energy and transfer of air energy

Replies
34
Views
603
Replies
5
Views
426
Replies
7
Views
676
Replies
30
Views
565
  • Last Post
Replies
2
Views
338
  • Last Post
Replies
2
Views
365
Replies
4
Views
312
Replies
1
Views
229
Replies
8
Views
422
Replies
4
Views
281
Top