Helmholtz Free Energy

Helmholtz Free Energy

In thermodynamics, the Helmholtz free energy is a thermodynamic potential that is defined as the internal energy of the system minus the product of the temperature times the entropy of the system. it measures the “useful” work obtainable from a closed thermodynamic system at a constant volume and pressure.The Helmhotz free energy is defined as:

Helmhotz free energy - equation

The internal energy, U, has an exact physical meaning, it is the sum of all the kinetic and potential energies of all the particles in the system. The second term is the amount of spontaneous energy transfer, TS, where S is the final entropy of the system. For a constant temperature process the Helmholtz free energy gives all the reversible work. When a physicists say “free energy” without indicating Helmholtz or Gibbs, they usually means Helmholtz free energy, on the other hand, when a chemists say “free energy” they almost always means Gibbs free energy.

thermodynamic potentials - enthalpy
Thermodynamic Potentials; the term Ts represents the energy you can get from the system’s environment by heating; the term pV represents the expansion work.
 
References:
Nuclear and Reactor Physics:
  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. W.S.C. Williams. Nuclear and Particle Physics. Clarendon Press; 1 edition, 1991, ISBN: 978-0198520467
  6. G.R.Keepin. Physics of Nuclear Kinetics. Addison-Wesley Pub. Co; 1st edition, 1965
  7. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.
  8. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.

Advanced Reactor Physics:

  1. K. O. Ott, W. A. Bezella, Introductory Nuclear Reactor Statics, American Nuclear Society, Revised edition (1989), 1989, ISBN: 0-894-48033-2.
  2. K. O. Ott, R. J. Neuhold, Introductory Nuclear Reactor Dynamics, American Nuclear Society, 1985, ISBN: 0-894-48029-4.
  3. D. L. Hetrick, Dynamics of Nuclear Reactors, American Nuclear Society, 1993, ISBN: 0-894-48453-2. 
  4. E. E. Lewis, W. F. Miller, Computational Methods of Neutron Transport, American Nuclear Society, 1993, ISBN: 0-894-48452-4.

See above:

Energy