Passive cooling strategies in refurbishment of Mediterranean buildings: simulation analysis of thermal mass and natural ventilation combination

This paper aims to analyse in existing building refurbishments the complex relation between natural ventilation systems (single sided and cross ventilation, thermal chimney, evaporative cooling tower and earth pipes) and thermal inertia (medium-light and heavy) in the Mediterrean climate represented by three locations, Rome, Naples and Messina. Results show that, assuming equal comfort, the energy reduction potential is 67.7% with single-sided ventilation, 76.5% with cross ventilation, 30.2 with a thermal chimney, 20.1% with a cooling tower and 95.5% with earth pipes (where the consumption is due to the fan). In combination with the above-mentioned cooling strategies, the 30 cm thick wall maintains its role of thermal flywheel, while the 18 cm thick wall shows an excessive reactivity to climatic stresses, resulting in an average of 2.8% greater energy consumption. The scenario in Rome reaches the highest average energy consumption reduction for all the analysed systems (88.0%). Naples follows (83.1%) because of poor performance of the cool tower system (- 23.4%), while the scenario in Messina is last (71.4%) because of the low thermal range that limits the efficiency of all the systems without the pre-treatment of the outside air (-37.4%).