A two-dimensional ground heat loss model is used to investigate the ef
fect of bottom reflectivity on ground heat losses for solar ponds. In
the model, convection boundary conditions are used between water and g
round. The convection heat transfer coefficient is estimated using the
correlations given for heated or cooled flat plates. The local rate o
f absorption of the solar radiation in the pond is determined for the
direct and diffuse components by the exact treatment of the radiation
problem. The fractions of heat adsorbed by the pond bottom that is tra
nsferred to soil and to water are investigated for different bottom re
flectivities.