Climate resilience strategies for schools in mediterranean areas: is it feasible to condition air merely with ventilation?

Abstract

Managing energy costs in school buildings across Italy poses a significant challenge. Over time, various directives have aimed to reduce energy consumption and improve indoor air quality to enhance student and teacher performance. This study offers an innovative analysis of the thermal behavior of a school in a typical Mediterranean climate. The building envelope is designed to meet legal standards for thermal transmittance specific to its Italian climate zone. Using Termolog Epix 15 software, the study conducts dynamic annual and hourly simulations to assess operative temperature and relative humidity in classrooms, with the heating system turned off and varying air exchange rates. The results suggest that optimizing the building envelope can be more effective than installing traditional HVAC systems (heating, ventilation, and air conditioning) in warm climates, demonstrating the effectiveness of a mechanical ventilation system without heating or cooling. By analyzing the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indices, the study demonstrates that it is possible to maintain acceptable thermo-hygrometric comfort through the only ventilation. During winter, with air changes per hour ranging from 1 to 5, classrooms can maintain temperatures between 21 °C and 23 °C, ensuring thermal comfort without heating. Typically, a heating system would operate for approximately 1071 h annually, excluding holidays. However, an effective ventilation system could eliminate the need for heating entirely. While maintaining optimal temperatures in the intermediate months (spring/autumn) and summer is more challenging, this concern is mitigated by the fact that schools are closed during summer holidays.