At first, the term “cold local heating” sounds like a contradiction in terms. But in fact, cold heating networks are similar to conventional heating networks in their basic function. Water circulates in a pipe system as a heat transfer medium and transports the heat from a central heat source to the connected buildings. The key difference is the temperature level: while conventional heating networks are operated with flow temperatures of over 70 degrees Celsius, the temperatures in cold local heating networks are significantly lower - usually in the region of 10 degrees Celsius.

Due to these low temperatures in the local heating network, the heat energy circulating in the pipes is not sufficient to heat living spaces directly. Instead, decentralized water-to-water heat pumps are used in each connected building. These highly efficient systems raise the temperature level in the local heating network to the flow temperature required for heating the building. We have explained exactly how a heat pump works in more detail in a separate article.

The combination of cold local heating and a decentralized heat pump offers numerous advantages over conventional heating systems or a classic heating network.

Important advantages

• Provision of heating and cooling possible
• No insulated pipes necessary, as only low heat loss
• In addition to geothermal energy, waste water and groundwater heat, ambient air or solar thermal energy can be used as energy sources
• Low maintenance and servicing costs
• Coupling the heat and electricity sectors
• Grid-friendly operation thanks to flexible system control and heat pump control

But there are also potential disadvantages

• Property owners have a comparatively higher initial investment due to the transfer station with heat pump
• Implementation in existing neighborhoods requires a comparatively high level of effort, as the decentralized heat pumps have to be integrated into the existing buildings
• Larger pipe diameters due to the higher volume flows
• Additional fallow water heat pump required in every household

Using a variety of different heat sources requires more complex planning and control of the overall system

ENERGY EFFICIENCY AND COST SAVINGS

Due to the low temperature level, there is virtually no heat loss to the ground in cold local heating networks. This makes it possible to use inexpensive, uninsulated plastic pipes instead of thermally insulated pipes. In addition, the pipe network acts as a geothermal collector at operating temperatures below the ground temperature and thus absorbs additional heat from the ground.

COOLING AND AIR CONDITIONING INCLUDED

Another decisive advantage of cold heating networks is their ability to provide not only heat but also cooling - and to do so extremely energy-efficiently. The low network temperatures enable passive cooling of the connected buildings via heat exchangers. This type of air conditioning is not only invisible and noiseless, but also significantly more energy-efficient than conventional air conditioning systems.

VARIOUS HEAT SOURCES CAN BE USED

Cold heat networks can be fed from a variety of heat sources, including natural sources such as geothermal energy, solar energy, ambient air, groundwater and river water. However, anthropogenic heat sources such as industrial process and waste heat, waste heat from sewers, data centers or commercial cooling and refrigeration systems can also be integrated into the system. This flexibility enables precise adaptation to local conditions and efficient use of existing resources.

The potential of low-temperature sources is far from exhausted. By combining different sources, larger networks can be supplied and expanded. Technical progress, for example in the development of seasonal storage systems, is expanding the possible applications for heat pumps.

The exact number of cold local heating networks in Germany is difficult to quantify as there are no comprehensive statistics to date. But one thing is certain: the number is increasing. alpha innotec has already supplied heat pumps for various cold local heating networks. A number of district solutions are in the planning stage. You can always find current examples on our reference page.

The potential of this innovative heat supply solution is enormous - both for new development areas and for the renovation of existing neighborhoods. While cold local heating networks are already being used more frequently in new-build districts, they are still the exception rather than the rule in existing buildings. But here, too, they offer a promising alternative to decentralized heat pump solutions, especially when it comes to renovating entire districts.

The optimum solution for local heat supply always depends on the boundary conditions. If, for example, a waste heat source at a high temperature level is available, conventional heating networks may be the better choice. In areas with a very low heat demand density, decentralized heat pump solutions are often superior.

However, cold local heating networks offer an extremely attractive alternative for entire districts that are to be converted to a sustainable heating and cooling supply. They enable efficient and cost-effective conversion of a large number of buildings in one go, particularly in the case of district refurbishment.

HEAT PUMPS IN THE COLD LOCAL HEATING NETWORK CAN BE COUPLED DIRECTLY TO THE DYNAMIC SPOT MARKET

The ait Group has played a key role in the development of a new, AI-based energy management system specifically for heat pump operating grids. It can provide the power with watt precision to match the electricity load and connected energy generators such as heat pumps and PV systems participate in the spot market. It is assumed that the heat pump operating network, in conjunction with the innovative home energy management system, will significantly reduce the heating costs for buildings connected to the cold heating network compared to a gas condensing boiler, even at current energy prices. The target is 25 to 30 percent.

Are you interested in this topic? Contact us here and we will put you in touch with our local heating department.

Several factors of the innovative energy management system contribute to the improved efficiency and profitability of the cold heating network. Firstly, the appliances in the operating network can be controlled and regulated to the exact wattage, meaning that the power is always provided to match the electricity load. Secondly, they participate directly in the dynamic electricity market. This means that electricity is primarily purchased when it is cheapest - or even when it has fallen into negative territory. It goes without saying that the heat pumps can also be controlled by the distribution grid operator to serve the grid.

Despite all the planning challenges, cold local heating networks in combination with heat pumps offer enormous potential for a sustainable and efficient heat supply. They can be a sensible alternative to decentralized heat pump solutions, particularly in densely populated areas where a large number of buildings need to be supplied.

However, the expansion of cold heating networks depends not only on technological aspects, but also on political framework conditions and strategic planning at municipal level. Municipal heating planning that takes the advantages of cold local heating networks into account can make an important contribution to achieving climate neutrality targets.

Only through close coordination between municipalities, energy suppliers, planners and property owners can the advantages of cold local heating networks be optimally utilized and integrated into a holistic strategy for the municipal heating transition.

For local authorities, housing associations and property owners, cold local heating networks represent a future-proof investment in a sustainable heat supply. By combining various renewable heat sources and the possibility of efficient cooling, they offer a long-term solution that meets both ecological and economic requirements.

Although the planning and implementation of such projects require a certain amount of initial outlay, the investment pays for itself in the medium term thanks to the low operating costs and independence from fossil fuels. Last but not least, cold local heating networks help to achieve ambitious climate protection targets and preserve an environment worth living in for future generations.

Just get in touch with us. Together with experienced industry partners, we will create the right energy concept for a climate-neutral heat supply in new or existing buildings. In many cases, this will be a sustainable cold local heating network in conjunction with sustainable and reliable heat pumps.