Abstract
This doctoral research is set in the Italian context where the enhancement of the energy performance of the built environment has been a priority for the past decades and has become even more urgent since winter 2022, with the hiking fuel and electricity prices. Indeed, large part of the local building stock dates back to the XX century and shows poor energy performance and suboptimal indoor environmental quality IEQ. Specifically, the urgency of enhancing buildings energy performance and IEQ is particularly evident in the school building stock: although being intended to guarantee thermal comfort in the heating season, school buildings often exhibit inadequate thermal environment conditions in the fall–winter months, leading to widespread thermal discomfort both in dated and recently constructed schools. Furthermore, in the latest years, they have been used with growing frequency to host summer school activities in the summer months from June to September, and, due the warmer temperature conditions and heat waves occurring in the spring–summer season, indoor thermal discomfort is often experienced, impacting negatively on occupants’ task performance. In this context, faced with the rising energy prices and the widespread poor IEQ conditions in the local building stock both in the fall-winter season and in the spring-summer months, the revalorization of the local built environment and the definition of energy refurbishment plans for both public and private buildings have become of primary importance for local public authorities. Given these considerations, it is relevant to note that, as several researchers pointed out, public buildings refurbishment should act as optimal model to guide retrofit interventions for the entire built environment and specifically school buildings should play the role of exemplary guiding refurbishment plans for the local building stock. Based on the points previously made and the state-of-the-art in the field, this doctoral research aims at the definition of solutions and strategies for the energy performance enhancement of public school buildings, with the final goal to provide recommendations and guidelines to the public administration for developing effective energy management and retrofit plans for the local building stock. To achieve the main research objective, this research is structured around four milestones: first (I Objective), the assessment of the effectiveness and the impacts on IEQ of the energy-saving operation measures for buildings HVAC systems recommended by local public administrations in the heating season 2022-2023 to face the rising energy prices. Then, the evaluation of whether, after the lifting of the energy-saving measures recommended in 2022-2023 for public buildings, any best practice for an efficient operation of buildings energy systems has been maintained and the assessment of the following impacts on indoor thermal comfort, air quality and occupants’ task performance. Secondly (II Objective), the study of the applicability of the proposed heating systems operation control measures in both dated and recently constructed public schools based on the assessment of the energy savings extent and the building capability to maintain acceptable indoor thermal comfort conditions. In a third phase (III Objective), the analysis of solutions and strategies to simultaneously optimize the indoor thermal environment and the energy performance of schools in the spring–summer months. Lastly (IV Objective), the assessment of different ventilation solutions in public school buildings, and specifically in classrooms, in the heating season to define effective strategies to optimize the energy performance and guarantee adequate levels of IEQ and students’ learning performance at the same time. To carry out the whole work, the methodology implemented is based on the analysis of a set of four representative case-study school buildings in the municipality of Bolzano. Specifically, to reach the I Objective, the assessment of the fuel consumption data for heating systems operation and of the IEQ, based on the indoor environmental data collected during the monitoring campaigns conducted in the case-study buildings from the fall-winter 2022-2023 to October 2024, was performed via spreadsheet and python programming. On the other hand, to satisfy the II, III and IV Objectives, the energy performance simulation of the case-study buildings was carried out via EnergyPlus software. Furthermore, to satisfy the IV Objective, the detailed modelling of ventilation strategies was done combining EnergyPlus software with custom python scripts to expand the software modelling capabilities. Results of this work confirmed some findings from previous studies and highlighted the importance of considering buildings specific features when defining both deep energy retrofit interventions and simple energy efficiency operation measures. Furthermore, it allowed to gain an insight into the way buildings of relatively dated and recent construction and with different features respond to different energy performance enhancement strategies, from basic operation control measures to ventilation solutions for the heating season, as well as strategies from passive to active ones for the warm season.