Building Network (Local Heating Network)
The term building network (in German "Gebäudenetz") is a type of local heating network that supplies up to 16 buildings and a maximum of 100 residential units from a central heat source. It plays a crucial role in the German subsidy program BEW, particularly for sustainable heat supply using renewable energies or 5GDHC networks. This article explains the exact definition according to German GEG law, its advantages, and the funding options for building networks.
Definition: What is a Building Network?
A building network is defined in §3 Paragraph 1 No. 9a of the Building Energy Act (GEG) as a heating network exclusively supplying heat and cold for at least two and up to 16 buildings (residential or non-residential) and up to 100 residential units.
Building Network vs. Traditional Local Heating Network
| Feature | Building Network | Traditional Local Heating Network |
|---|---|---|
| Supply Size | 2–16 buildings, max. 100 residential units | Larger districts & municipalities |
| Heat Sources | Heat pumps, solar thermal energy, waste heat | CHP, biomass, geothermal energy |
| Temperature Range | Low temperature (5GDHC network possible) | 50–120°C |
Funding for Building Networks
Under the Federal Funding for Efficient Heating Networks (BEW), the construction of heating networks is subsidized if at least 75% of the heat comes from renewable energies or waste heat. For building networks supplying at least two and up to 16 buildings, a funding requirement of at least 65% renewable energy or unavoidable waste heat applies. The promotion of systems like "5GDHC network," which operates at low temperatures and uses decentralized heat pumps, is particularly attractive as such systems typically utilize a high proportion of renewable energy.
5GDHC network as Part of a Building Network
5GDHC network is an efficient and sustainable technology for building networks. It utilizes low temperatures (0–20 °C) from natural or technical sources, which are then raised to the required level using decentralized heat pumps.
Possible Energy Sources for 5GDHC network:
- Wastewater & sewer networks
- Wastewater treatment plants
- Inland waters (lakes, rivers)
- Deep boreholes & well drilling
- Ground collectors, trench collectors & geothermal baskets
- Ice storage & underground/water storage
- Ice fences
- Source networks for heat pumps
Cost Allocation for Building Networks with 5GDHC network
The BEW funding practice outlines a specific cost allocation for building networks using 5GDHC network:
- Costs for deep drilling, ice storage, and local heating pipelines are distributed among all connected existing buildings.
- Costs for decentralized heat pumps are assigned to the respective buildings.
- In business parks or large corporate sites, deep drilling, heat exchangers, and heat pumps can be consolidated in a central non-residential building (NRB).
Conclusion
Building networks offer an efficient and sustainable alternative to individual heating systems. In particular, 5GDHC networks provide a future-proof solution for climate-friendly heat supply. Thanks to BEG and BEW funding, these networks are economically attractive and a key technology for the heat transition.
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