In this paper we develop a theoretical thermal study of optical fibres tran
smitting concentrated solar energy. An energy equation for simultaneous con
duction and radiation of heat through optical fibres is obtained. To transm
it concentrated solar energy an optical fibre tip is placed in the focus of
a small paraboloidal mirror. The role of aluminium and silver as the refle
ctive surface on the mirror that allows one to concentrate the solar energy
is studied. The power supply is estimated to be 26 W at the end of a 10 m
long fibre with 88%, transmission efficiency. The thermal study considers a
wavelength-dependent absorption coefficient of the optical fibre core in o
rder to obtain the radiative heat Bur in the fibre. The time evolution of t
he temperature distribution is obtained by a finite-difference method. With
this result we predict that the fibre can be used 6 h.