On the Evaluation of Solar Greenhouse Efficiency in Building Simulation during the Heating Period

Among solar passive systems integrated in buildings, sunspaces or solargreenhouses represent a very interesting solution. A sunspace is a closed, southboundvolume, constituted by transparent surfaces, adjacent to a building, which reduces winterenergy demand thanks to the use of solar gains. The effect of a typical solar greenhouse onthe energy balance of a building was evaluated during the heating period with twostationary procedures (Method 5000 and EN ISO 13790) and with a dynamic tool(TRNSYS). After the analysis of the greenhouse alone, the behavior of an entire house wassimulated; a flat equipped with a sunspace, recently built thanks to public contributionsprovided by the Umbria Region in Italy to widespread bio-climatic architecture, was usedas case-study. Simulations were carried out for the examined flat, both with a steady-statetool and with a dynamic one; the contribution of the sunspace was estimated thanks to thevarious methods previously mentioned. Finally, the simulated data were satisfactorilycompared with the real energy consumptions (natural gas for heating) of the flat; thesunspace allows a reduction of winter energy demand of the flat of about 20%.