Evaporative Cooling and Ventilation Control Strategies for a Kindergarten in Mediterranean Climate

Aim of this work has been to determine the effectiveness of evaporative cooling and ventilation control strategies on a case study to ensure an adequate combination between energy efficiency and high levels of indoor comfort. The case study has been a kindergarten, situated in the context of the climate continental Mediterranean area (Cerignola, Italy, 41°16'00"N, 15°54'00"E, 120 m asl), oriented on an east/west axis, classrooms south faced, and the services zone to north. Several strategies for passive and hybrid cooling of the classrooms have been simulated in order to reduce the overheating in the summer season and to reach high levels of air quality. Different solutions have been simulated to evaluate the optimum operative conditions, through the TRNSYS simulation software. The first design strategy have regarded a night hybrid ventilation (from 10 p.m to 6 a.m.). The thermal comfort analysis, according to the adaptive thermal comfort (EN 15251-2007), have shown the reduction of overheating and the need to introduce a control logic, in relation to the outdoor temperature, to reduce the undercooling in the early hours of occupancy. It has been necessary to provide a ventilative cooling strategy also during daytime in order to obtain a significant reduction of overheating. The second design strategy has involved the adoption of a direct evaporative cooling system. The simulation have concerned different combinations of evaporation efficiency and air flow rates. The results have shown the optimal air flow rate for different evaporation efficiencies. Analysis on relative humidity levels have shown that the evaporative cooling system did not significantly alter the levels of relative humidity and there was a positive increase in the minimum levels of relative humidity. This study have underlined that passive cooling systems, operated by a suitable control logic, can provide performance levels almost comparable with those of an air conditioning system, ensuring a significant reduction of energy consumption.