Energy dissipation bounds for autonomous thermodynamic cycles
Samuel J Bryant1, Benjamin B Machta1,2
1Department of Physics, Yale University, New Haven, CT 06520; samuel.bryant@yale.edu benjamin.machta@yale.edu.
Abstract:
How much free energy is irreversibly lost during a thermodynamic process? For deterministic protocols, lower bounds on energy dissipation arise from the thermodynamic friction associated with pushing a system out of equilibrium in finite time. Recent work has also bounded the cost of precisely moving a single degree of freedom. Using stochastic thermodynamics, we compute the total energy cost of an autonomously controlled system by considering both thermodynamic friction and the entropic cost of precisely directing a single control parameter. Our result suggests a challenge to the usual understanding of the adiabatic limit: Here, even infinitely slow protocols are energetically irreversible.
Related Concept Videos
The Carnot Cycle
What could be the theoretical limit to the efficiency of a heat engine? The...
The Carnot Cycle and the Second Law of Thermodynamics
Since the individual steps in a Carnot cycle can be reversed, the entire cycle is, thus, reversible. If a Carnot cycle is reversed, it becomes a Carnot refrigerator. It extracts heat Qc from a cold reservoir at...
Efficiency of The Carnot Cycle
Entropy Change in Reversible Processes
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
Entropy
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
Entropy


