We propose an extended model for the climatization of an ecological building. Solar radiation is the main energy source. The theoretical approach includes models for: (i) generating meteorological data; (ii) generating solar radiation data; (iii) optimum operation of a photovoltaic array; (iv) thermal interactions between building and ambient; (v) operation of the climatization system; and (vi) operation of the refrigeration system. Preliminary results show that the photovoltaic array provides all of the energy required to drive the climatization system in midsummer on clear days. The Romanian standard STAS 6648/1-82 overestimates the thermal load of the climatization system. The development of more sophisticated computing procedures is desirable. We show the influence of the type of day (with clear or covered sky) and of solar-cell quality on both the thermal load and the power delivered by the photovoltaic array.