title: Efficiency at maximum power of a chemical engine.
abstract: A cyclically operating chemical engine is considered that converts chemical energy into mechanical work. The working fluid is a gas of finite-sized spherical particles interacting through elastic hard collisions. For a generic transport law for particle uptake and release, the efficiency at maximum power η(mp) [corrected] takes the form 1/2+cΔμ+O(Δμ(2)), with 1∕2 a universal constant and Δμ the chemical potential difference between the particle reservoirs. The linear coefficient c is zero for engines featuring a so-called left/right symmetry or particle fluxes that are antisymmetric in the applied chemical potential difference. Remarkably, the leading constant in η(mp) [corrected] is non-universal with respect to an exceptional modification of the transport law. For a nonlinear transport model, we obtain η(mp) = 1/(θ + 1) [corrected], with θ > 0 the power of Δμ in the transport equation.
authors.affiliation: Instituut voor Theoretische Fysica, KU Leuven, B-3001 Leuven, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Hooyberghs
authors.forename: Bart
authors.initials: B
authors.lastname: Cleuren
authors.forename: Alberto
authors.initials: A
authors.lastname: Salazar
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Indekeu
authors.forename: Christian
authors.initials: C
authors.lastname: Van den Broeck