A dynamic energy performance-driven approach for assessment of buildings energy Renovation—Danish case studies

Abstract

In this study, four buildings in Aarhus, Denmark are considered for energy renovation analysis and assessment aiming to enhance their energy performance. A systematic and dynamic energy performance-driven methodology for buildings energy modelling, simulation and renovation was developed and implemented based on an overall technical, economic and environmental assessment. Detailed dynamic energy performance models were developed for the buildings considering various specifications, envelope characteristics and energy supply systems configurations. The models were calibrated using actual energy consumption data and occupancy schedules. Buildings primary energy consumption in the range of 158–192kWh/m2 of indoor heated area was reported, highlighting large potential for energy performance improvement. Based on field visits, systems and components inspections, technical managers interviews and users feedback, various energy renovation measures and packages were prioritized and investigated employing a holistic approach and considering the technical, economic and environmental impacts of each package. It was found that a renovation package comprising LED lights, efficient equipment, heating circulation pump replacement and ventilation system upgrade is favourable allowing average energy savings of 27.7% with a payback period less than 4 years and average CO2 emissions reduction of 5.1t/year in the four buildings. However, considering indoor air quality and thermal comfort along with the Danish building energy standards and requirements, a deep energy retrofit package was recommended through improving energy supply systems efficiency and upgrading the buildings envelope. Average energy savings of around 50% were reported with an estimated payback period of 11 years. Moreover, the option of including a 4kWpPV system along with the deep energy retrofit package was investigated and was found to save up to 71% on the primary energy consumption with average reduction of 115kWh/m2, allowing the four buildings to be classified as BR15 Renovation Class 1, the highest class for renovated buildings in Denmark.