Climate optimised building parameters for low energy summer comfort under a discomfort index

An in-dept analysis of a large office building built in the 60s (occupied by the Italian Ministry for the Environment, chosen for its representa- tivity of buildings built in the 50Ks and 60Ks) has been performed. A software model of the build- ing has been created and used to simulate its be- haviour in the climate zone of Rome, using a dynamic simulation software. Then a building with the same geometry and same internal gains but with higher storage mass (m > 350 kg/m2, calculated with the method of Heindl T ISO 13786, 1994), selective glazing (U value of windows < 1,8 W/m2K), movable ex- ternal blinds (solar factor: g < 0,15) and a sim- ple night ventilation strategy has been simulated and optimized to achieve good comfort condi- tions at low or no energy consumption for me- chanical cooling. Blinds have been designed and simulated to obtain required shading without penalizing daylighting. We calculate the values of the thermo- physical parameters which minimise a discom- fort index. elaborated starting from the PMV scale of Fanger. Comparison of the coriginal buildingsd to the coptimized buildingsd shows: - a 85% reduction of discomfort index suppos- ing the buildings are not air-conditioned; - a 30% to 80% reduction in energy consump- tion for cooling supposing the buildings are air-conditioned. A consequent reduction of greenhouse gases emission up to 70÷100 tCO2-eq/year. The analysis leads to a proposal for munici- pal building codes optimized to the climate zone, where the installation of air conditioning is allowed, in new buildings or large retrofits, only if certain target values are achieved by the building envelope and structure.