energy balance equation

Thermodynamic potentials can be derived from the energy balance equation applied to a thermodynamic system.

Anything that passes across the boundary that effects a change in the internal energy needs to be accounted for in the energy balance equation.

Below is the energy balance equation of the rate of energy lost of a solar balloon when drawing the boundary line around the balloon.

Moreover, the Gibbs free energy equation, in modified form, can be utilized for open systems when chemical potential terms are included in the energy balance equation.

ECLIPSE uses the finite volume method to solve material and energy balance equations modelling a subsurface petroleum reservoir.

On the other hand, the HD method solves the DD scheme with the energy balance equations obtained from the moments of the Boltzmann Transport Equation (BTE).

For well-understood processes these approximations can be very accurate (e.g. using mass & energy balance equations) while for other processes precise physical models do not exist and the used approximations can be quite crude.