  Radiant spherical suspensions have an $\veps$-periodic distribution in a
tridimensional incompressible viscous fluid governed by the Stokes-Boussinesq
system. We perform the homogenization procedure when the radius of the solid
spheres is of order $\veps^3$ (the critical size of perforations for the
Navier-Stokes system) and when the ratio of the fluid/solid conductivities is
of order $\veps^6$, the order of the total volume of suspensions. Adapting the
methods used in the study of small inclusions, we prove that the macroscopic
behavior is described by a Brinkman-Boussinesq type law and two coupled heat
equations, where certain capacities of the suspensions and of the radiant
sources appear.
