In this work, an analysis of the thermophysical processes taking place inside a specially designed chamber with a geometry different from other works was carried out. This process is designed in COMSOL Multiphysics software. Boundary conditions were investigated for ambient temperature of 293.15 K and solar radiation of 1000 W/m2. The process was taken as natural convection. In this case, the flow of air with high humidity inside the solar water heater was analyzed. It can be seen that the air temperature rises to 450 K. At the same time, the speed of moist air inside the chamber, heat flow and other thermophysical quantities were determined and analyzed.