Realisation of energy performance targets of an old apartment building renovated to nZEB

Anti Hamburg, Kalle Kuusk, Alo Mikola and Targo Kalamees

Energy, 2020, vol. 194, issue C

Abstract: Energy performance of buildings directive sets a goal to achieve a highly energy efficient and decarbonised building stock by 2050. In this study, a pilot nZEB (nearly zero energy building) renovation of an existing apartment building is analysed. nZEB criteria of new apartment buildings was set as the energy performance target in designing renovation solutions. The whole building envelope was additionally insulated with prefabricated modular panels and new service systems were installed. Measured energy consumption after the renovation showed that the pilot building fulfilled the minimum energy performance requirements for new apartment buildings, but nZEB target was not achieved. Measured heating energy consumption is 1.6 times higher (mainly because of the higher indoor temperature, supply air temperature, window airing, and higher ventilation airflow rates which methodology for heating energy calculations are not taken into account) and measured energy need for DHW is 4.4 times higher (mainly because of the real use profiles as well unexpected performance of solar collector and sewerage heat recovery system) than expected in building design. Results show that in renovation projects (also in new projects), occupant behaviour and the real use of building should be used as more realistic input parameters for designing energy performance. Distribution and circulation losses of air handling units, heating coils and DHW (domestic hot water) systems should be taken into account in the national energy calculation methodologies as service system heat losses can be a significant part of energy consumption at nZEB levels. If the renovated building would be used according to design methodology, the nZEB target can be achieved.

Keywords: Deep energy renovation; Energy performance; Performance gap; nZEB (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (15)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:194:y:2020:i:c:s0360544219325691

DOI: 10.1016/j.energy.2019.116874

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