  Turbulent convection models treat stellar convection more physically than
standard mixing-length theory by including non-local effects. We recently
successfully applied the Kuhfuss version to convective cores in main sequence
stars. Its usefulness for convective envelopes remains to be tested. The solar
convective envelope constitutes a viable test bed for investigating the
usefulness of the 1-equation Kuhfuss turbulent convection model. We used the
one-dimensional stellar evolution code GARSTEC to calculate a standard solar
model with the 1-equation Kuhfuss turbulent convection model, and compared it
to helioseismic measurements and a solar model using standard mixing-length
theory. Additionally, we investigated the influence of the additional free
parameters of the convection model on the solar structure. The 1-equation
Kuhfuss model reproduces the sound-speed profile and the lower boundary of the
convective region less well than the mixing-length model, because the inherent
non-local effects overestimate the amount of convective penetration below the
Schwarzschild boundary. We trace this back to the coupling of the temperature
gradient to the convective flux in the 1-equation version of the Kuhfuss
theory. The temperature stratification of the solar convective envelope is not
well modelled by the 1-equation Kuhfuss turbulent convection model, and the
more complex 3-equation version is needed to improve the modelling of
convection in the envelopes of 1D stellar evolution models.
