Municipal heating plan for Kiel: Potential analysis for air source heat pumps
As part of the municipal heat planning (KWP: “Kommunale Wärmeplanung”) of the state capital Kiel, we conducted a potential analysis for decentralized air source heat pumps. Using our building-specific models, we can determine for each individual building in the entire Kiel city area whether an air source heat pump can be installed on the site in compliance with legal requirements for noise protection.
Motivation
According to the “Klimaschutzgesetz”, Germany must achieve a climate-neutral heat supply by 2045. With the “Wärmeplanungsgesetz” (WPG) coming into force in January 2024, municipalities were obliged to implement a KWP. In Schleswig-Holstein, the KWP is regulated by the “Energiewende- und Klimaschutzgesetz“ (EWKG). This law obliges certain municipalities, including upper and middle centers, to draw up heat plans by the end of 2024, which is earlier than the WPG at the federal level. As an upper center, the city of Kiel is subject to this regulation.
Project Objectives
A KWP includes the steps of status analysis, potential analysis, target scenario, and implementation strategy. As part of the potential analysis, the potential for technologies for heat supply based on renewable energies is determined. Decentralized heat pumps play an important role in this. Air source heat pumps currently account for the largest share of decentralized heat pumps in Germany and are expected to continue to do so in the future. The aim of the FfE’s work as part of Kiel’s heat planning was to make small-scale assessments of the basic feasibility of air source heat pumps while complying with legal requirements for noise protection. This is because air source heat pumps cause noise emissions. A key aspect is therefore the distance between potential installation sites for air source heat pumps and neighboring residential buildings. The methodology described below was used to analyze where in the Kiel urban area the conditions for the suitability of air source heat pumps prevail.
Methodology
Whether an air source heat pump can be installed and operated depends, in addition to the existing heating system (radiators, pipe system), mainly on whether legal noise protection limits can be complied with. The models developed as part of the “Wärmepumpen-Ampel” project to determine the decentralized potential for air source heat pumps, taking sound insulation into account, were further developed in this and other KWP projects and applied to individual building data in Kiel. In order to quantify the potential, the following three questions need to be answered:
How loud are air source heat pumps? (Noise emissions)
The noise emissions of air source heat pumps were taken from an analysis of manufacturer data on a good 100 systems from the Heat Pump Traffic Light project.
How loud can the noise from air source heat pumps be at the immission location (neighboring residential buildings)?
Using geodata from the land-use plan (“Flächennutzungsplan”), specific immission limits were assigned to the buildings according to area category (see TA Lärm, BImSchG [1]).
Where are air source heat pumps located and how far are they from the immission location?
For each individual building, potential installation sites and their distance from neighboring residential buildings were determined using GIS analysis. Figure 1 shows a schematic representation of the GIS analysis process used to determine the limiting distance between installation sites and neighboring residential buildings.
Based on the applicable noise protection limits, the emissions of the devices, and the limiting distances between the installation site and neighbors, a heat supply potential was determined for each building and compared with the heat requirements from the status analysis. This allowed us to deduce which buildings could potentially be supplied with air source heat pumps and which could not.
A detailed description of the methodology is included in the final report on Kiel’s heat planning.
Results
The analysis shows that around 68% of buildings in Kiel can be supplied with air source heat pumps from a sound insulation perspective. The proportion is particularly high in areas that require decentralized supply. Figure 2 shows the results at the building block level.
In certain areas, it is not suitable for a heating network and also has low potential for air source heat pumps. These areas have been designated as decentralized supply areas with special advisory services. These are areas where, due to dense building development, the legal regulations on sound insulation cannot be complied with in all buildings. A detailed analysis of terraced houses was carried out in these areas. Middle terraced houses in particular have relative low potential due to limited installation options and the short distances to neighboring buildings. As part of the detailed analysis, it was examined whether the potential would increase if terraced house complexes were supplied collectively via a central air heat pump at one end of the complex instead of each individual house supplying itself. This increased the potential for the terraced houses examined in the decentralized areas with special advisory services from 47% to 68%. The exact technical implementation (piping, placement of indoor units, etc.) and specific regulations, taking into account the interests of various building owners in such building networks, must be investigated in practice.
The results are incorporated into Kiel’s spatial heating plan, which divides the city into areas that are either suitable for district heating expansion, where local heating networks are a suitable option, or where a decentralized individual solution for buildings is possible.
Project Partners
The potential analysis was carried out on behalf of Averdung Ingenieure & Berater for the City of Kiel. Other institutions involved in the KWP Kiel project were ZEBAU (Zentrum für Energie, Bauen, Architektur und Umwelt) and Prognos.
More Information
- Kommunale Wärmeplanung in Kiel
- EE-Wärmepotenzialstudie im Rahmen der Kommunalen Wärmeplanung Hamburg
- Wärmepumpen-Ampel
Literature
[1] Sechste Allgemeine Verwaltungsvorschrift zum Bundes-Immissionsschutzgesetz (Technische Anleitung zum Schutz gegen Lärm – TA Lärm). Ausgefertigt am 26.8.1998, Version vom 1.6.2017; Bonn: Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit, 2017.