Gravity and thermodynamics-driven generator idea

[aleks]

The idea:

1. Have a tube filled with gas, with a piston inserted into it from top. Piston imposes pressure on the gas inside the tube due to gravity pull.
2. Have an array of heaters inside the tube heat the gas.
3. Have several 'oven doors' attached to tube's sides that open thermodynamical contact of gas with thermo-electric generator panels (Seebeck effect).
4. Have a system that periodically heats the gas, opens the 'oven doors' and closes them.
5. Have a multi-phase system built from such tubes drive the turbine.

a) This will work given the COP of thermo-electric generator is high. As far as I know, there are devices that give 80% COP if the gas has a high temperature (due to Carnot's formulation).
b) Tube should be thermally insulated from the surrounding air. Tube should be ventilated with outdoor air to ensure low temperature of outer side of the thermo-electric panel.
c) Output of thermo-electric panel of a given tube is fed to heat gas in surrounding tubes.

The principle is simple: when gas is heated, it will push the piston up; when 'oven doors' are opened, this will decrease temperature of the gas while giving electrical output; when gas' temperature is lowered, piston goes down due to gravity pull. Energy is lost in the thermo-electric generator only. It is actually gained from gravity pull.

[aleks]

Just to give you a better perspective of this idea, if COP of thermoelectric conversion is 100%, this device is probably infinitely efficient: the amount of free energy it produces is fully scalable.

[tinu]

http://www.varmaraf.is/engl/faqgen.htm
"3. What is the efficiency of Thermoelectric Generators?
The efficiency is about proportional to the temperature difference between the hot and cold fluids. With 70?C difference the efficiency is about 3%."

Comments:
1. Thermoelectric Generators obey Carnot. (Figures like 80%-90+% are given most probably in respect to Carnot maximum theoretical efficiency.)
2. Oven doors are not necessarily needed; one can use adiabatic heating.

Cheers,
Tinu

[aleks]

1. Thermoelectric Generators obey Carnot. (Figures like 80%-90+% are given most probably in respect to Carnot maximum theoretical efficiency.)

www.powerchips.gi

And I've also read that some Russian engineers have done it just about a year ago (80% or so thermoelectrical conversion efficiency from burning natural gas achieved - it's not just a Carnot efficiency).

This is probably the same as JTEC: http://www.johnsonems.com/ - 60% COP at 600 degree C difference.

Please update your notes.

Also, if you know, when temperature difference is 1500 degrees C, Carnot maximum is about 85%. So, in the worst case the overall efficiency will be around 65% - this may be enough for the idea to work if scaled properly. Not sure about 1500 degrees C difference - looks a bit steep, but I'm just showing the idea.

[aleks]

2. Oven doors are not necessarily needed; one can use adiabatic heating.

Not sure how this'll help to engage thermoelectric electricity generation (AND temperature dropping) at the required moment only.