Multi-Energy School System for Seasonal Use in the Mediterranean Area

Abstract

School buildings represent an energy-consuming sector of real estate where different efficiency actions are necessary. The literature shows how the design of a multi-energy system offers numerous advantages, however, there are problems related to the integration of cogeneration units with renewable energy sources due to the low flexibility of the first one and the high degree of uncertainty of the latter. The authors provide an alternative solution through the analysis of a case study consisting of a multiple energy system in three Sicilian schools, focusing on the system’s operational strategy, on the design and sizing of components and trying to exploit the energy needs complementarity of buildings instead of integrating the conventional energy storage systems. Not considering school activities in summer, it was decided to install a cogeneration unit sized on winter thermal loads, whereas the electricity demand not covered was reduced with photovoltaic systems designed to maximize production for seasonal use and with loads concentrated in the morning hours. The effectiveness of this idea, which can be replicated for similar users and areas, is proved by a payback time of less than 11 years and a reduction of 31.77% of the CO2 emissions.

Comment on Pietrapertosa et al. How to Prioritize Energy Efficiency Intervention in Municipal Public Buildings to Decrease CO2 Emissions? A Case Study from Italy. Int. J. Environ. Res. Public Health 2020, 17, 4434

“…of inert gas, methane combustion stoichiometry and CO 2 to methane molar mass ratio of 2.75, results in a more realistic NG emission factor of around 180 g of CO 2 per kWh higher heating value, or of around 200 g of CO 2 per kWh lower heating value. This complies with the NG emission factor applied by D Amico et al [6].…”

“…Specific cost of CO 2 emissions reduction, SC CO2 (€/t), relates the economics and the associated environmental benefit of applying individual measures. It is calculated by Equation (6), where an average 25-year lifetime period of energy saving measures is assumed and emission factors EF en of 180 kg/kWh for natural gas and 400 kg/kWh for electricity are adopted. SC CO2,i,j = I i,j AS i,j .EF en .25 (6) Values of A h,j , AS i,j , WH j , I i,j , and n j were extracted from data Tables A1-A3 in Appendix A.…”