Availability and Dissipativity in Networks: Foundations of Process Control

We use the second law of thermodynamics to derive conditions under which an irreversible system has actions which satisfy the dissipation inequality. These actions have an inner product structure due to superlinearity of the entropy. A link between classical, non‐equilibrium thermodynamics and the input‐output passivity theory of nonlinear control is then established. The paper represents a step towards developing a passivity based approach for control and inversion of highly distributed chemical process systems. The theory is illustrated by applying it to a (Hamiltonian) molecular dynamics system with a thermostat.