Is it possible to supply Norwegian apartment blocks with 4th generation district heating?
4th generation district heating represents the new generation of district heating systems. It reduces heat loss from the grid, enables better use of surplus heat and renewable energy sources, in addition to reducing the strain on the electricity grid. In short, 4th generation district heating is a sustainable solution for supplying heat to Zero Emission Neighbourhoods.
However, there are technical challenges that must be solved before it is introduced. One of them is to determine how low the supply temperature can be in different types of buildings so that we can identify the minimum district heating supply temperature. In our research, we evaluated the minimum supply temperature in Norwegian apartment blocks by improving the thermal envelope and reducing the temperature levels for the heating system. Our analysis focuses on whether the reduced supply temperature guarantees thermal comfort in the building.
Our project implied developing a database of building models representative of Norwegian apartment blocks. The building models consisted of eight age groups and three levels of energy performance. We performed simulations with two different temperature levels for the radiators typical for Norwegian buildings: 80/60 and 60/40 °C.
We found that reducing the supply temperature to the radiators from 80 to 60 °C is possible for buildings newer than from 1970, even for non-renovated buildings. For older buildings, an intermediate renovation, i.e. upgrading the windows, is necessary to maintain temperatures above the minimum acceptable temperature of 19 °C. Still, we highly recommend to perform a more ambitious renovation for these buildings to reduce the number of hours with significantly reduced indoor temperature compared to the setpoint temperature of 22 °C. In addition to reduce the heating demand and thus achieve energy savings, this will also ensure that the occupants are satisfied with their thermal environment.
The results can be used by district heating companies, building owners, contractors and consulting companies, in order to evaluate the introduction of 4th generation district heating in Norwegian apartment blocks. The models and Excel sheets with hourly results for energy need are available for partners and researchers within FME ZEN, so that they could be used for other purposes as well.
By Øystein Rønneseth
Energies, 12 (5), https://doi.org/10.3390/en12050941