Renovating primary school buildings in Malta to achieve cost-optimal energy performance and comfort levels

Abstract

The Energy Efficiency Directive requires that 3% of the floor area occupied by public buildings be renovated each year to meet the Minimum Energy Performance Requirements (MEPRS) based on the Cost Optimal Methodology (COMet) as defined by the EPBD. The MEPRS for the retrofitting of schools in Malta still have not been defined. In this study, an innovative and energy efficient COMet approach for the retrofitting or Public Primary School Buildings (PPSBs) in Malta has been applied. All current PPSBs are naturally ventilated and have diverse footprints and envelope constructions. This prompted us to move away from the commonly adopted COMet approach, which assumes that one or two Reference Buildings (RBs) are sufficient for defining the MEPRS for all schools and that the building is assumed to be mechanically ventilated with active heating/cooling sources to reach comfort defined by pre-determined temperature set-points. In contrast, this paper aims to achieve comfort using the EN 15251 adaptive thermal comfort approach for naturally ventilated buildings and provides an Excel tool that calculates the MEPRS based on the actual building construction and orientation. Results have shown that for summer, the PPSB can attain adaptive comfort if its glazing is externally shaded and night purging is applied.