Introduction The European legislation has established ambitious targets for achieving high energy performances, with the aim for new buildings to reach nearly zero-energy use (NZEBs) by the end of 2020. Universities, playing... [ view full abstract ]
Introduction
The European legislation has established ambitious targets for achieving high energy performances, with the aim for new buildings to reach nearly zero-energy use (NZEBs) by the end of 2020. Universities, playing an exemplary role in modern societies, should take the lead in analysing energy efficiency and proposing retrofit measures in their own buildings, targeting NZEB.
This study analyses 20 buildings of 4 campuses in the University of Lleida, in terms of building operational and geometric data, energy use, renewable production and current gap to NZEB targets.
Methods
The following steps have been applied: 1) compiling building data, renewable energy production and energy consumption; 2) performing overall and detailed analysis ; 3) assessing the actual gap between university building energy performance and Spanish NZEB goals.
Results and Discussion
Fig. 1 shows annual gas and electricity use per floor area. The two Health Sciences buildings E19 and E20 are highlighted as the major consumers. The rest of the buildings are in the range 50-175 kWh/m2·year, comparable to the values reported by the UPC, which are between 40 and 200 kWh/m2·year.
Fig. 2 shows the historical evolution of the annual renewable energy production in the two campuses with installed PV systems. Note that the two campuses have a decreasing trend in PV output production, with about 3% reduction per year. This efficiency drop per year is higher than the typical 1% drop given by many PV manufacturers and should be studied in more detail.
In Fig. 3 shows the calculated total primary energy consumption. The horizontal red lines correspond to the maximum threshold range. The buildings E2, E6, E12, E13, E15 and E18 have primary energy consumptions close to the maximum thresholds. Buildings E19 and E20 are very far from the NZEB concept. The non-HVAC services, such as specific labs, have a critical impact over the energy performance of these two buildings. The other 12 buildings have values around 2.5-3 times higher than the maximum thresholds, indicating that many improvements should be implemented to reduce this gap.
