Decarbonized energy supply of the building stock through system-serving bidirectional cold local heating networks

Focus topic:	Resource efficiency
Type of funding:	Project funding programmes
Programme:	CZS Transfer
Funded institution:	Hochschule Karlsruhe – Technik und Wirtschaft

The aim of the project is to decarbonize the heat supply of existing buildings and thus dispense with fossil natural gas. To achieve this, cold local heating networks are designed bidirectionally and solar heat from the summer is stored seasonally in the ground and used in the winter.

Goals

The Federal Climate Protection Act envisages a reduction in CO2 emissions in the building sector of around 45 % compared with 2019. By 2045, the entire building stock is to be virtually climate-neutral. To achieve these goals, there must be a move away from fossil fuels for energy supply (decarbonization).

The energy-efficient use of heat pumps in existing buildings represents a key step in this process. Through "bidirectional cold local heating networks" (bkN), heat pumps can also be used energy-efficiently in winter because of the seasonal storage of solar heat in the ground. Buildings that cannot supply themselves with sufficient solar heat are co-supplied by other buildings. In addition, the flexibility of the system is used by increasing the use of heat pumps when a lot of renewable electricity is fed into the power grid and the price of electricity is low as a result. In this way, they have a system-serving effect, i. e., they support the integration of renewable energies.

By taking into account the findings from projects on bkNs in new buildings, the project will develop methods for identifying cost-efficient structures and control strategies. The methods will be developed based on an existing existing area, which will become a lighthouse project for the implementation of bkNs.