A simple configuration is described for harnessing solar energy using natural convection. A solar collector and warm air store of modest height generate a buoyancy force which draws ambient air through the configuration. Incoming air is required to pass through a convergent-divergent nozzle where it is accelerated to high velocity. A turbine sited at the throat of the nozzle intercepts this kinetic energy of airflow generating electricity. A laboratory model (1 x 1 x 1.5m) is described for which earlier CFD studies gave promising results. Readers are asked to build an apparatus for experiment to improve on earlier results and to develop the model. If such work is successful, theoretical calculations are presented for a field scale prototype (solar collector 10 x 10m) and for a large scale Modular Unit (100 x 100m). Such Modular Units could be built in repeat patterns on desert or arid land in hot climates to generate an average of over 80MW/square kilometer.