Assessing the nearly zero-energy building gap in university campuses with a feature extraction methodology applied to a case study in Spain

Marc Medrano,Mohammed Farid,Jordi Cipriano,Gerard Mor,Josep Maria Martí,Lídia Rincón

doi:10.1007/s40095-018-0264-x

Abstract

Public universities face the challenge of retrofitting the actual campus buildings into nearly zero-energy buildings (NZEB). In this study, a novel methodology for evaluating historical energy use and renewable energy production for all the buildings of a university, including hourly, daily and monthly data assessments is presented. This analysis is useful as a baseline for comparisons with future energy retrofits and enables determining the current gap between actual energy indicators at building and campus levels and the established limits for NZEB non-residential buildings in the European Union. The methodology is applied to a case study at the University of Lleida, a typical average-size university in Spain. Results show a wide variation in energy use among campus buildings, ranging between 50 and 470 kWh/m2 year. Constant or slightly increasing energy use and decreasing trends in renewable energy generation are observed. The daily electricity profiles have shown similar patterns among buildings and substantial potential energy savings during unoccupied periods. In the NZEB analysis, the average non-renewable primary energy use is about 4 times higher than the maximum estimated Spanish threshold range of 45–55 kWh/m2 year. Deep energy renovation strategies are, thus, needed for universities to meet EU NZEB targets.

Highlights

The building sector is the main contributor to the total energy use in the European Union (40%) and accounts for 36% of the associated C O2 emissions [1]
The Energy Performance of Building Directive (EPBD) of the EU has established a broad definition for nearly zero-energy buildings (NZEB), i.e., “a building that has a very high energy performance
As an example of a Member State that has been able to give detailed figures for the broad framework of EU NZEB definition, Denmark has established a primary energy consumption limit for non-residential buildings to be below 25 kWh/m2 year by

Summary

Introduction

The building sector is the main contributor to the total energy use in the European Union (40%) and accounts for 36% of the associated C O2 emissions [1]. The European legislation (Directive 2010/31/EU on energy performance of building, EPBD) 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 [2, 3]. An international agreement for defining and evaluating the performance of NZEB is difficult, as discussed elsewhere [6, 7]. In this context, the EPBD of the EU has established a broad definition for NZEB, i.e., “a building that has a very high energy performance. As an example of a Member State that has been able to give detailed figures for the broad framework of EU NZEB definition, Denmark has established a primary energy consumption limit for non-residential buildings to be below 25 kWh/m2 year by

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