  Geometrothermodynamics is a geometric theory which combines thermodynamics
with contact and Riemannian geometry. In this work we use the formalism of
geometrothermodynamics to infer cosmological models which predict the observed
speed up. As a relevant consequence, our simple model shows dynamical
properties which seem to fairly well describe the late time universe dynamics.
To do so, we use geometric considerations about constant thermodynamic
curvature and derive the model of a fluid which is expected to \emph{naturally}
reproduce the dark energy effects. In particular, our approach reduces to the
$\Lambda$CDM model in the limiting case of small redshift, providing however
significative departures from $\Lambda$CDM as the universe expands. The main
goal consists in interpreting our \emph{geometrothermodynamic fluid} as an
energetic source and to explain the dark energy effects as emerging from the
interplay between geometry and thermodynamics, providing a new interpretation
of the observed positive acceleration.
