The effect of building refurbishment and changing occupancy on the district heating consumption of multifamily buildings: Case study of Miskolc, Hungary

Abstract

Present paper aims at identifying the effect of a business-as-usual refurbishment of multifamily buildings and the increased occupancy in the dwellings on the heating energy consumption. For the study data from the district heating provider of the city of Miskolc, Hungary was used. For the study two types of data was analysed: monthly heating consumption data for 619 buildings for the time period of 2015-2020 and 10-min data for 64 district heating substations for the time period of 2018-2022. From the monthly heating consumption data, the effect of building renovations were assessed using energy signature diagrams and energy performance gap analysis. The examined 619 buildings were sorted in 7 building types and the data for the insulated and uninsulated buildings were compared. To evaluate the effectiveness of the refurbishments the energy performance gap was calculated based on the measured data and was obtained from dynamic building simulations as well. From the simulations the business as usual refurbishment for deep renovation showed 71–76 % decrease in energy consumption, while the measured energy consumption decrease was only between 37 and 58 %, which translates to a 17–39 % energy performance gap. From the high-resolution consumption data the effect of the increased occupancy presence due to the COVID pandemic was examined. A total of 5622 daily profiles were analysed using the k-means clustering method for 4 different periods. Despite the expectations the results showed that the pandemic had not changed the daily district heating consumption profiles of the examined buildings.