Overunity from Heating and Cooling

  • Context: Graduate 
  • Thread starter Thread starter etherist
  • Start date Start date
  • Tags Tags
    Cooling Heating
Click For Summary

Discussion Overview

The discussion revolves around the concept of overunity in the context of heating and cooling gas, specifically steam. Participants explore the kinetic energy of gas molecules and the implications of cooling steam to achieve what is suggested to be an overunity effect, raising questions about energy conservation and the validity of the calculations presented.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant presents a calculation of the kinetic energy of steam and suggests that cooling it results in an overunity effect, questioning the assumptions behind this conclusion.
  • Another participant clarifies that the kinetic energy formula used is based on average kinetic energy derived from the Maxwell-Boltzmann distribution.
  • There is a discussion about the definition of overunity, with one participant explaining it as achieving greater output than input, which raises concerns about violating the law of conservation of energy.
  • Some participants express skepticism about the feasibility of overunity processes, noting that they are considered fringe topics within the forum.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the validity of the original claim regarding overunity. There is a general agreement that overunity processes are controversial and often dismissed, but the specific calculations and assumptions remain contested.

Contextual Notes

Limitations include potential misunderstandings of kinetic energy calculations, the assumptions made in deriving the overunity claim, and the implications of energy conservation laws that are not fully resolved in the discussion.

Who May Find This Useful

Readers interested in thermodynamics, energy conservation, and the theoretical implications of overunity concepts may find this discussion relevant.

etherist
Messages
16
Reaction score
0
The kinetic energy of gas molecules or atoms is: (3/2)kTN/M where k is Boltzmann constant, T is absolute temperature, N is avogadros number and M is molecular weight. The formula is derived from http://en.wikipedia.org/wiki/Kinetic_theory.
Assume that the gas is steam with M = 18 kg/mol at 373K, it is equivalent to approximately 260 J/kg but suppose i cool the steam up to 40C based on Cdt + Lf (C is specific heat, dt is change in temperature and Lf is latent heat of vaporization), it becomes an overunity of 10420 more effective. From what assumption or derivation I am wrong? or if I'm right where does the excess energy came from?
 
Last edited:
Science news on Phys.org
That is the AVERAGE kinetic energy! It is a statistical ensemble derived via Maxwell-Boltzmann distribution!

Zz.
 
  • Like
Likes   Reactions: 1 person
yes i compute the average kinetic energy of the molecules and then i multiply it with the total number of molecules using avogadros number and molecular weight so i computed the total kinetic energy1 kg steam of approximately 260 J, which is very small.
 
I actually computed the total kinetic energy since the average kinetic energy is only equal to kT/2.
 
Last edited:
etherist said:
The kinetic energy of gas molecules or atoms is: (3/2)kTN/M where k is Boltzmann constant, T is absolute temperature, N is avogadros number and M is molecular weight. The formula is derived from http://en.wikipedia.org/wiki/Kinetic_theory.
Assume that the gas is steam with M = 18 kg/mol at 373K, it is equivalent to approximately 260 J/kg but suppose i cool the steam up to 40C based on Cdt + Lf (C is specific heat, dt is change in temperature and Lf is latent heat of vaporization), it becomes an overunity of 10420 more effective. From what assumption or derivation I am wrong? or if I'm right where does the excess energy came from?
What is overunity? I've never heard the term before.
 
It means that efficiency is greater than 1 or 100%, there is a gain of energy which violates law of conservation of energy.
 
Chestermiller said:
What is overunity? I've never heard the term before.

It's when you get more out than you put in - so very near the fringe of what's acceptable on PF.

Suffice to say that someone with the time and inclination could find the flaw in the OP but there are better things to do with your time than chase things like that.
 
Yes, overunity processes are on the banned topics list of the PF. Thread is closed.
 

Similar threads

Undergrad Calculating Cooling Effect in Gas Cylinder Expansion
  • · Replies 5 ·
Replies
5
Views
5K
Graduate Help setting up heat transfer equation
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Energy balance over a methanol reformer
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Adiabatic gas cooling/heating: Explaining Conceptually
  • · Replies 2 ·
Replies
2
Views
2K
High School What causes the drop of latent heat at lower temperatures in liquid helium?
  • · Replies 2 ·
Replies
2
Views
3K
I have a few questions about refrigeration and AC units
  • · Replies 1 ·
Replies
1
Views
3K
Graduate Joule Expansion: Cooling Effects & Kinetic Energy
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Find amount of H20 needed to cool Steel
  • · Replies 8 ·
Replies
8
Views
3K
Graduate Thermo: Calculating the temperature drop from gas leaving a system
  • · Replies 11 ·
Replies
11
Views
10K
How does humidity affect air cooling?
  • · Replies 11 ·
Replies
11
Views
3K