Author Topic: Recover energy from temperature (Read 26577 times)

MarkE · « **Reply #30 on:** January 23, 2014, 07:26:34 PM »

rc4 this looks like a gear pump. Are you thinking that somehow this pump will run itself to increase the pressure difference? The external forces will operate so as to attempt to equalize the pressures.

rc4 · « **Reply #31 on:** January 23, 2014, 08:20:49 PM »

Look at images please, it's not a gear pump, gear don't press gas. I use gears only for prevent the gas at 1 bar to move inside vacuum. Gas press volume, and I recover energy inside vacuum recipient. If you see a torque somewhere I will be ok, but here I don't find a torque, so where is lost energy ? The only energy I can see it's lost is the small space between teeth when gears are in action. It can be very low:

http://commons.wikimedia.org/wiki/File:Involute_wheel.gif

You can imagine big radius for wheel, like that the volume lost for each volume is very low. There are gaskets inside teeth of gears.

g5 image: W = win energy, L = lost energy. If I consider gear/gear move in => lost energy, the sum is 0 and is I consider gear/gear move out => lost energy, the sum is 0 too. Look at direction of gears.

MarkE · « **Reply #32 on:** January 24, 2014, 12:56:05 AM »

Quote from: rc4 on January 23, 2014, 08:20:49 PM

Look at images please, it's not a gear pump, gear don't press gas. I use gears only for prevent the gas at 1 bar to move inside vacuum. Gas press volume, and I recover energy inside vacuum recipient. If you see a torque somewhere I will be ok, but here I don't find a torque, so where is lost energy ? The only energy I can see it's lost is the small space between teeth when gears are in action. It can be very low:

http://commons.wikimedia.org/wiki/File:Involute_wheel.gif

You can imagine big radius for wheel, like that the volume lost for each volume is very low. There are gaskets inside teeth of gears.

g5 image: W = win energy, L = lost energy. If I consider gear/gear move in => lost energy, the sum is 0 and is I consider gear/gear move out => lost energy, the sum is 0 too. Look at direction of gears.

If your mating gear tooth faces are not gas tight then it just leaks. If they are gas tight then it is an air pump. In either case as air pressure changes there will be loss to heating / cooling. This machine like the last one is subject to the Second Law of Thermodynamics like all others.

rc4 · « **Reply #33 on:** January 24, 2014, 01:07:32 AM »

There is no gas inside between tooth, it's not an air pump. But, if energy is not lost here, where is it ? I can pass volume with 1 bar (look at 4 images please) inside vacuum container without need energy and I can pass volume of 0.5 bar inside container of 1 bar without energy. Could you help me to find the error ?

MarkE · « **Reply #34 on:** January 24, 2014, 02:10:51 AM »

rc4 if the gears rotate then volume between any pair of teeth on one gear and the meshing tooth of the other gear varies as the two gears rotate relative to one another.

rc4 · « **Reply #35 on:** January 24, 2014, 10:33:55 AM »

Yes, I understood the torque is not the same, one part act on small radius for one gear and one part act on big radius for another gear.

But here, in the image, if I cancel pressure when the tooth is inside pressure = 0, all the time gas act for 4 surfaces so no torque, and for cancel pressure of this small volume of gas I lost less energy no ? Could you explain please ?

MarkE · « **Reply #36 on:** January 24, 2014, 06:10:06 PM »

Quote from: rc4 on January 24, 2014, 10:33:55 AM

Yes, I understood the torque is not the same, one part act on small radius for one gear and one part act on big radius for another gear.

But here, in the image, if I cancel pressure when the tooth is inside pressure = 0, all the time gas act for 4 surfaces so no torque, and for cancel pressure of this small volume of gas I lost less energy no ? Could you explain please ?

Your illustration shows operation of a gear pump. If the lower gear rotates CCW gas is being pumped to the lower left. If the lower gear rotates CW, gas is being pumped towards the upper right.

rc4 · « **Reply #37 on:** January 24, 2014, 06:24:28 PM »

No, it's not a pump, look at images, where tooth are one inside other, I don't pump gas, I use gears like gasket. Each tooth has a valve, this valve recover PdV for each step. The only place I can loose energy is at the middle, but if the volume between teeth (at the middle) is near 0 (image big radius for gears), I don't lost PdV.

rc4 · « **Reply #38 on:** January 25, 2014, 02:24:37 PM »

I understood, it's because gaskets are usefull for one gear, this not works for second. So I lost that I won : 2 PdV

Now if I put the gasket in the center of blue arrow:

http://commons.wikimedia.org/wiki/File:Involute_wheel.gif

I compute torque, it must be the same energy than 2 PdV.

R1 = small radius of gear
R2 = big radius of gear
P = 100 000 Pa

I found the result in the second image, so 1/6 of PdV, where is the error please ?

rc4 · « **Reply #39 on:** January 31, 2014, 09:09:23 PM »

Another idea:

Take a screw (worm drive) with N starts (increase lead). The thread is used for move out vacuum objects and recover energy from temperature. The torque I need to give of the screw is T/N with N the number of starts and T the torque I need with one start. In one turn I can move out the same volume of vacuum object than with one start (The slope change when N increase) but here the torque is lower and divided by N. I drawn an image with 3 starts for example. Imagine walls of threads like very (very) thin for put N very high.

The part of thread inside vacuum: add wall for full the thread to obtain a cylinder (a perfect cylinder). Like the screw turn, all object with vacuum in it move up. I need to give a torque for turn the screw, but I recover N times I need to give.

Second image: multiple starts, but imagine thin of thread very thin (where the is solid on the thread)

Third image: I need to give a torque of the slope of one start only, but the lead so the volume of vacuum move out is multiplied by 2. The energy needed fot the torque is C*Θ, Θ = 2pi for one turn. C is the torque for one slope, but the lead is multiplied by 2 so the volume of vacuum object is pi(R2²-R1²)*lead.

rc4 · « **Reply #40 on:** February 01, 2014, 10:05:57 AM »

The thickness of worm drive thread is equal to thickness of gear. When I turn one turn I move up a tooth to one pitch, but the thickness of thread increase the distance. I move to 2 teeth. A gear give PV for tooth/notooth (a pitch), so here the sum of energy is 0, but if thickness of thread is near 0, in one turn of worm drive I move up one tooth, the next turn too, but gear give/recover energy only for one tooth, after it's a blank.

PiCéd · « **Reply #41 on:** February 01, 2014, 03:31:41 PM »

Quote

P = 100 000 Pa

Ok 100 000 Pa, but if the volume is too litle 0.000001 m³ or lesser it will be almost nothing. How many anions or cations are produced with this?

rc4 · « **Reply #42 on:** February 03, 2014, 11:20:29 PM »

Another idea:

All under pressure P.

Roll up a full solid on a screw. The screw turn only. S1>S2.

rc4 · « **Reply #43 on:** February 08, 2014, 12:10:46 PM »

If I take a cycle like that ?

rc4 · « **Reply #44 on:** February 11, 2014, 08:28:42 PM »

Surface S1 = Surface S2 but direction are not the same, so the torque are not the same too, no ?

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