  The hydrodynamic equation governing the homogeneous time evolution of the
temperature in a model of confined granular gas is studied by means of the
Enskog equation. The existence of a normal solution of the kinetic equation is
assumed as a condition for hydrodynamics. Dimensional analysis implies a
scaling of the distribution function that is used to determine it in the first
Sonine approximation, with a coefficient that evolves in time through its
dependence on the temperature. The theoretical predictions are compared with
numerical results obtained by the direct simulation Monte Carlo method, and a
good agreement is found. The relevance of the normal homogeneous distribution
function to derive inhomogeneous hydrodynamic equations, for instance using the
Champan-Enskog algorithm, is indicated.
