Decarbonisation of the building sector is a vital task to cut greenhouse gas emissions and reach Europe’s climate targets. This paper presents a novel refurbishment concept which allows the substitution of a fossil-fuelled heating system with a heat pump solution via the addition of a retrofitted thermal activation of the façade for buildings dating from the 1950s and 1960s that can be implemented in full operation of the building. Furthermore, monitoring data from the heating season 2024/25 is used to establish the temporal behaviour of the heat generation system (air-to-water heat pumps), to describe the energy fluxes between various components of the heating system (heat generation, distribution and release), and to evaluate the efficiency of the heating system. The monitoring data used consists of temperature measurement data of the indoor and outdoor environment as well as the heating water flow and return temperatures and façade core temperatures. Additionally, heat meter data for various points in the heating system is used as well as electricity meter data of the heat pumps. Calculated values for amounts of heat generated are cross-validated using heat meter data where available. Results show that in comparison to the available heat meter data, the modelling approach for the thermal power quantification of the heat pumps results in overestimation which would need to be fixed by obtaining more data on the heat pumps’ actual efficiency behaviour (COP) for various operating parameters. Finally, the SPF of the heat pumps was established for an observation period of approximately three weeks in January/February 2025 and was found to amount to 3.9.
Rzihacek et al. (Thu,) studied this question.