Idea of "SMA SunMill"

[Khwartz]

SMA Mill / Hairs / Recalled / Gravity / Mass×4:+7 cm & Faster


Using gravity to recall the SMA (nitinol) "hair", at the cooling phase.

● Mass is near quadruple compare to 2 video before:

Power been proportional to the mass, we have: M3[kg] / M1[kg] = 4, thus +300 % of increase of power transfer.

● + 7 cm of radius increase for initial 1.5 cm radius: 7 [cm] / 1.5 [cm] = 4.6, thus + 360 % (to compare to +20% two videos before):

Power been proportional to the radius, we have: 4.6 / 1.2 = 3.8 , thus + 280 % of increase of power transfer.

● The change of shape is 2 times % faster:

Power been proportional to the frequency (1/T), we have +100 % of increase of power transfer.

● The increases of power transfer multiplying each other we get: 4.0 × 4.6 × 2 = 36, thus 3,500 % more power transfer (36 times more powerful under the same thermal power input).


■ Real mechanical power transferred (raw estimate):

Let's say screws are 10 g.

Power [W] = energy [J] / time

= (weight [N]. lift [m]) / time

= ((mass [kg] * gravitation [m.s^-2]). lift [m]) / t

= ((0.010 [kg] * 10 [m.s^-2]) * 0.10 [m]) / 10

= 0.001 [W]


■ Area of cylinder needed to obtain 1 kW:

○ nitinol wire diameter: 0.5 mm

○ area of the scare in which we inscribe the wire section at the "foot" of the "hair" (SMA wire): 0.5^2 = 0.25 mm2

○ number of hairs needed to obtain 1 kW:

• 1,000 W / 0.001 W/hair = 1,000,000 hairs.

○ 1,000,000 hairs × 0.25 mm2
= 250.000 mm2
= 25 m2.

Which would be still pretty much for an only 1 kW heat motor.


Note: the masses of the screws are 2 orders of magnitude heavier than the nitinol wire (in the range of an hundred times heavier, maybe 50 to 150 times more, should measure and calculate later).

https://youtu.be/EcI8OIyuoYc

[Khwartz]

Hello SoManyWires! Thanks for your post and pictures, it helps me much to have them to understand what is written ^_^

I know these stuff.

Don't see for now how I could use it for my project but why not!

Oh, yes, it remembers me a configuration of solar dilatation mill, but the round shape looks to not be optimal in this kind of use, pure cylinder shape, and of course with axis horizontal, looks to me the best geometry.

The purpose of these "SMA mills" is just to make a heat motor to produce, hopefully, usable clean energy based, by use of the gravity while we unbalance continually the cylinder, by use of differential temperature to run the actuator (the parts which change of shape to move masses), by SMA to make the actuators working with the temperature differential.

Regards,
Didier.

[Khwartz]

SMA Mill / Hairs / Recalled / Gravity / Mass×4:+7 cm & Faster


Using gravity to recall the SMA (nitinol) "hair", at the cooling phase.

● Mass is near quadruple compare to 2 video before:

Power been proportional to the mass, we have: M3[kg] / M1[kg] = 4, thus +300 % of increase of power transfer.

● + 7 cm of radius increase for initial 1.5 cm radius: 7 [cm] / 1.5 [cm] = 4.6, thus + 360 % (to compare to +20% two videos before):

Power been proportional to the radius, we have: 4.6 / 1.2 = 3.8 , thus + 280 % of increase of power transfer.

● The change of shape is 2 times % faster:

Power been proportional to the frequency (1/T), we have +100 % of increase of power transfer.

● The increases of power transfer multiplying each other we get: 4.0 × 4.6 × 2 = 36, thus 3,500 % more power transfer (36 times more powerful under the same thermal power input).


■ Real mechanical power transferred (raw estimate):

Let's say screws are 10 g.

Power [W] = energy [J] / time

= (weight [N]. lift [m]) / time

= ((mass [kg] * gravitation [m.s^-2]). lift [m]) / t

= ((0.010 [kg] * 10 [m.s^-2]) * 0.10 [m]) / 10

= 0.001 [W]


■ Area of cylinder needed to obtain 1 kW:

○ nitinol wire diameter: 0.5 mm

○ area of the scare in which we inscribe the wire section at the "foot" of the "hair" (SMA wire): 0.5^2 = 0.25 mm2

○ number of hairs needed to obtain 1 kW:

• 1,000 W / 0.001 W/hair = 1,000,000 hairs.

○ 1,000,000 hairs × 0.25 mm2
= 250.000 mm2
= 25 m2.

Which would be still pretty much for an only 1 kW heat motor.


Note: the masses of the screws are 2 orders of magnitude heavier than the nitinol wire (in the range of an hundred times heavier, maybe 50 to 150 times more, should measure and calculate later).

https://youtu.be/EcI8OIyuoYc

You may be shocked by the number of hairs, and ask yourself what would be the projected cost of the hairs for 1kW ?

With these numbers, but with industrial price, only nitinol, would be something like:

Total length of wire: 1,000,000 hairs * 0.1 m = 100,000 m

Section of wire: (0.0005 m / 2)^2 * Pi = 2*10^-7 m²

Volume of wire: 100,000 m * 2*10^-7 m² = 0.02 m3

Mass of wire: 0.020 m3 * 6,500 kg/m3 = 130 Kg

Investment in wire: 130 Kg * 200 $/kg = 26 000 $

But 1 kW solar panel is 20 $ from the same kind of sourcing ("made in China"), thus we are 3 orders of magnitude of cost to high.



We need to divide by 1 thousand the estimate of cost.


With global and hard heating on the full length of wire (it was only progressive along the hair so it took much more time to heat it all along), we may be possibly able to achieve:


SMA Mill / Hairs / Recalled / Gravity / 10 g:+7 cm & 1 s


■ Real mechanical power transferred (raw estimate):

Let's say a lifting mass is 10 g.

Power [W] = energy [J] / time

= (weight [N]. lift [m]) / time

= ((mass [kg] * gravitation [m.s^-2]). lift [m]) / t

= ((0.010 [kg] * 10 [m.s^-2]) * 0.10 [m]) / 1

= 0.01 [W]


■ Area of cylinder needed to obtain 1 kW:

○ nitinol wire diameter: 0.5 mm

○ area of the scare in which we inscribe the wire section at the "foot" of the "hair" (SMA wire): 0.5^2 = 0.25 mm2

○ number of hairs needed to obtain 1 kW:

• 1,000 W / 0.01 W/hair = 100,000 hairs.

○ 100,000 hairs × 0.25 mm2
= 25.000 mm2
= 2.5 m2.

But still 2 orders of magnitude to high...


To make it, we should have for example:

Power [W] = energy [J] / time  = 1 kW

= (weight [N] * lift [m]) / time = 1 kW

= ((mass [kg] * gravitation [m.s^-2]) * lift [m]) / t = 1,000 W

= ((100 [kg] * 10 [m.s^-2]) * 1 [m]) / 1 = 1,000 W


How much mass of hairs we should need, if proportional to the mass lifted:

■ Mass of a hair?

○  Length of a hair: 0.1 m

○  Section of hair: (0.0005 m / 2)^2 * Pi = 2*10^-7 m²

○  Volume of a hair: 0.1 m * 2*10^-7 m² = 2*10^-8 m3

○  Mass of a hair: 2*10^-8 m3 * 6,500 kg/m3 = 1.3*10^-4 Kg

○ Mass lift by a 10 cm hair: 10 g

○  Number of hairs needed: 100 kg / 0.01 kg = 10,000 hairs

○  Total mass of hairs:  10,000 hairs * 1.3*10^-4 Kg = 1.3 Kg

○  Investment in wire: 1.3 Kg * 200 $/kg = 260 $


Maybe I have confused in my first calculations when I got 130 kg, between the total mass lifted and the total mass of hairs needed.

This later time I have taken in account the two different quantities but not the courage for now to check my previous calculations of total nitinol mass needed. If you want to check yourself and indicate the correction, don't hesitate, the publication of these calculations is made for.


We are still 1 order of magnitude too high in the best case, and with 20 $ for 1 kW solar panel China sourcing like for nitinol sourcing, looks to me it will be hard to be cheaper with this kind of system.

Didier

[Khwartz]

Hi All Of You (even if I don't know if anybody else than Peter - he will recognize himself - follows this thread ^_^ )!

After many tries, many attempts, I didn't succeed to get a TWO WAYS MEMORY-SHAPE EFFECT sufficient for our use with the nitinol wires I have received few weeks ago, only few percents of self returning to martensite shape when cooled.

I have asked estimates to suppliers in US and China of 1 kg of all kind of diameters of nitinol wires and thickness of nitinol sheets, with the martensite and austenite temperatures we are looking for (not 10-50°C but 40-70°C at least) but none of them sent me back a price.

Other problem: 1 kW photovoltaic solar panel, while sourced in China for example, is only 20 € (if I have not mistaken, of course, by hundreds of meters-scare), while nitinol whith the very same sourcing is between 100 to 400 € a kilogram. By my raw calculations you should check their rightness by yourself, it would need kilograms to acheive this kW of power. Thus, it looks like

it is not economically relevant.


An other problem again: I think

that would be not an ecological apparatus

because of the very probable not clean industrial process to produce nitinol alloys (but should need to be checked if it's true).


Thus, that idea of SMA Unbalanced Mill,

unless we get SMA Alloys in the correct range of change temperatures shapes and ecological enough SMA alloys

looks to me a deadlock,

sorry, but thanks for your possible interest.

Regards,
Didier