FROM NEARLY ZERO ENERGY BUILDING (NZEB) TO ZERO-EMISSION BUILDING (ZEB) - CONCEPT ISSUES EMPHASIZED THROUGH A PARADOXICAL CASE STUDY

A case study for a public library which aim to become nearly Zero Energy Building (nZEB) is presented. Due to buildings location in the city center of a medium sized municipality from Romania, important site limits have to be considered, as well as other pre-existent conditions. These conditions significantly limit the technological options that can be implemented to ensure nZEB compliance. Also, the destination itself of the building (library with free access to the shelves), imposes a specific energy profile (considering the intrinsic energy demand for its normal operation) and is limiting the inclusion into a very specific nZEB benchmark. Between obligations and possibilities, a cutting-edge package of technical solutions is detailed, which allows the building in operation to produce final energy almost as much as it consumes. However, a paradoxical situation is identified, in the sense that the building does not fit into the nZEB benchmarks, nor into the outlined ZEB benchmarks if the total primary energy is considered (both from conventional and renewable sources), although the implementation of the technical solutions actually lead the building to inclusion towards a CO2 zero-emission building (with a calculated value for the CO2 emissions of 5,26 kgCO2/m2.year and significantly reduced final energy consumption). Thus, a structural problem in the nZEB and ZEB concepts (as defined in the EU framework) is identified, especially in the context of making these concepts mandatory in the EU member states.