An Evaluation of the Environmental Payback Times and Economic Convenience in an Energy Requalification of a School

Francesco Asdrubali,Luca Evangelisti,Paolo Matteucci,Daniela Venanzi,Gianluca Grazieschi,Claudia Guattari,Marta Roncone

doi:10.3390/buildings11010012

Abstract

The majority of Italian schools (70%) were built in the absence of any legislation related to energy efficiency, and therefore have very low energy performance due to aging or poor quality of construction. An energy retrofit of this building stock is needed to meet the current European goals on greenhouse gas emission reduction. The retrofit is also needed in order to guarantee adequate comfort levels in indoor spaces and good conditions for learning and educational activities, that are often not reached in poor quality constructions. This work presents the results of an interdisciplinary study related to the energy requalification of a school located in Ostia, near Rome in Italy, built in the 1960s with a steel structure and Eternit infill. The scope of the analysis is to verify the economic and environmental effectiveness of four proposed retrofit interventions concerning the replacement of fixtures and the installation of an insulating coat. The current thermal transmittance of the walls was evaluated through thermofluximetric measurements conducted in situ; dynamic simulations were performed to determine the current energy performance and the energy performances following the four proposed retrofit scenarios. Energy and carbon payback times were evaluated (by means of the life cycle analysis (LCA) approach) and the economic value was determined for each of the four proposed retrofits, using a probabilistic approach. The results show that the replacement of windows is the most convenient intervention from all points of view. The study provides evidence that an assessment of schools’ energy retrofits should include both economic and life cycle aspects.

Highlights

The construction sector is responsible for around 40% of final energy consumption and 36% of greenhouse gas emissions in Europe
The database of the Italian Ministry of Education (MIUR) accounts for about 59,000 buildings, 70% of which were built in the absence of any legislation related to energy efficiency [2], and they were built before 1976, when the first law on this topic was promulgated in Italy
The paper is organized as follows: In Section 2, we describe the materials and methodologies used for the energy, economic, and life cycle analysis; in Section 3, we introduce the case study; in Section 4, we report the results of the study; while in Section 5, we provide the conclusions

Summary

Introduction

The construction sector is responsible for around 40% of final energy consumption and 36% of greenhouse gas emissions in Europe. Public buildings represent an important opportunity to promote energy efficiency and reduce consumption and climate-altering emissions. Due to aging or because of their poor construction quality, are in critical condition, and their energy systems are quite old and inefficient. Zomorodian et al [3] showed that adequate levels of ventilation were fundamental to guarantee good indoor air quality in classrooms and that students’ thermal preferences could not be in the comfort range provided by the standards. Since a comfortable environment increases concentration and learning [5], indoor comfort levels in school buildings, as well as their consequent energy performance, are of primary importance

Methods

Results

Conclusion